An Investigation into Player Compliance and Level of Protection Afforded by Mouthguards worn by Children Playing Sport in Ireland
A thesis submitted in partial fulfilment of the requirements for the degree of Doctorate in Dental Surgery (D.Ch.Dent.) in Paediatric Dentistry
2020
Elaine Philippa Shore
Supervisor: Dr. Anne O’Connell
Division of Public and Child Dental Health Dublin Dental University Hospital Trinity College, The University of Dublin
Declaration
I declare that this thesis has not been submitted as an exercise for a degree at this or any other university and it is entirely my own work.
I agree to deposit this thesis in the University’s open access institutional repository or allow the Library to do so on my behalf, subject to Irish Copyright
Legislation and Trinity College Library conditions of use and acknowledgement.
I consent to the examiner retaining a copy of the thesis beyond the examining period, should they so wish (EU GDPR May 2018).
______
Elaine Philippa Shore
I Glossary of Terms
TDI Traumatic dental injury
SRDI Sports-related dental injury
MG Mouthguard
MFMG Mouth-formed mouthguard (“boil and bite” type)
CMG Custom mouthguard
EVA Ethylene vinyl acetate
SD Standard deviation
IQR Interquartile range
PIL Participant information leaflet
II Summary
Background: Dental trauma is a significant global public health issue, affecting
1 billion people worldwide. Up to 40% of dental injuries are sports related and preventable through the use of mouthguards. In Ireland, the Gaelic Athletic
Association (GAA) introduced rules requiring the use of “properly fitted” mouthguards by players of all levels in 2014.
Aims: This study aimed to investigate compliance with GAA mouthguard rules among children playing Gaelic football in Ireland, and to establish the types and quality of mouthguards being worn. Knowledge, attitudes and behaviours of children and parents on dental trauma and mouthguard use were investigated.
Materials and methods: An observational cross-sectional cohort study was carried out using a convenience sample of 9-16-year-old boys and girls and their parents recruited from 4 Gaelic football teams from across Dublin city. Child and parent knowledge and attitudes regarding mouthguard use were established using questionnaires. Trained calibrated examiners examined the children’s dentition and mouthguards. Data were analysed using descriptive statistics, binary logistic regression analysis, and linear regression analysis.
Results: One hundred and twenty-one children with 118 parents participated in the study. The median age of the sample was 12 years (interquartile range = 10-
13) and there were slightly more males (56.67%) than females (43.33%). It was a highly active population with most children playing multiple sports. There was poor agreement between child (17.5%) and parent (6.84%) reports of past dental trauma and dentist-observed signs of dental injury (11.66%).
III Mouthguard use was greater for Gaelic football matches (99.17%) than for training (80.8%); binary logistic regression analysis concluded that older children are less likely to comply with mouthguard rules for training (OR = 0.18, p < .001).
Most children were only wearing their mouthguard for Gaelic football.
Most children (N = 87, 72.50%) reported that they liked their MG with few reported difficulties with wear (e.g. breathing, ability to speak). Knowledge of both parents and children regarding mouthguard hygiene was poor. Parents were willing to pay a median price of €35.00 (IQR = €20.00 - €50.00) for a custom mouthguard.
Mouth-formed mouthguards were the most popular type in this study; only 4 children (3.77%) had custom mouthguards. Most mouthguards (>80%) had inadequate retention and labial extension. Mean labial and occlusal thicknesses were greater than those recommended in the literature. Mouth-formed mouthguards were significantly thicker than both stock and custom mouthguards.
Conclusion: Mouthguards are routinely worn by children playing Gaelic football, with greater compliance during competition than during training. Compliance with mouthguard rules during training reduced as children grew older. Children and parents displayed favourable attitudes towards the use of mouthguards, though knowledge of hygiene measures was lacking. Most children were wearing mouth- formed mouthguards with poor retention and inadequate labial extension.
The quality and fit of the majority of mouthguards worn by children in this study was poor. There is a need for dentists to liaise with GAA clubs, players and parents to educate them on what constitutes a properly fitted mouthguard and how to care for these devices.
IV Acknowledgements There are many people without whom this research study would not have been possible, and I wish to take this opportunity to extend my thanks to each of them. To Ms Isabel Fleischmann, DDUH Librarian, for her help with constructing the search terms for the literature review. To Mr Glen Reid, DDUH laboratory technician, for fabricating the calibration mouthguards, and to Ardagh Dental, for sourcing and supplying the necessary EVA blanks for the calibration mouthguards. To Mr Noel Shore, for helping with modification and calibration of the callipers for data collection. To Dr Advan Moorthy, for being a willing volunteer for the calibration exercise. To Mr Gearóid Devitt and Mr Brendan Connolly and the Gaelic Athletic Association, and Ms Paula Prunty and the Ladies’ Gaelic Football Association, for their support and endorsement of this research being carried out in their member clubs. To those who facilitated contact with the GAA, LGFA, and individual clubs: Dr Sinead O’Sullivan, Mr Ryan Casey, Ms Marie Brady, Dr Joe Hennessy, Dr Frances O’Callaghan, and Ms Carol Maguire. To the executive committees, participants, and parents from Clanna Gael Fontenoy, St Vincent’s, Ballymun Kickhams, and Good Counsel GAA Clubs. To those who gave up their evenings after work to help with data collection: Dr Charlotte McCarra, Dr Emily Crossan, Dr Anne O’Connell, Dr Rona Leith, Dr Jennifer Maguire, Dr Hadeel Khraishi, Dr Niamh O’Kelly-Lynch and Dr Michael Donnelly. To Dr Maria van Harten and Dr Isabel Olegário da Costa for their guidance with the statistical analysis for this study. To Dr Anne O’Connell, my supervisor, for her time, encouragement and guidance throughout the past 3 years: I am truly grateful for everything. To Emily and Charlotte, for their support and friendship through the peaks and troughs of postgraduate life. To my sisters, Úna and MaryRose: Thank you for being great friends as well as wonderful sisters. To my husband, Conor – thank you for all the love, support and understanding, especially over the past 3 years, and for always being the voice of reason. Finally, to my parents: To my father, Philip, who encourages and supports me in working towards my ambitions, and makes sure my sense of humour stays intact; and to my late mother, Sheelagh, who was always so proud of my achievements, however small, and is dearly missed every day. I wouldn’t be where I am today without their example, their love and their encouragement.
V Table of Contents
Declaration ...... I
Glossary of Terms ...... II
Summary ...... III
Acknowledgements ...... V
Table of Contents ...... VI
List of Tables ...... XI
Table of Figures ...... XII
1 Chapter 1 Literature Review ...... 1 1.1 Background – Dental Trauma...... 1 1.1.1 Epidemiology of Dental Trauma ...... 1 1.1.2 Sports-Related Dental Injuries ...... 4 1.1.3 Consequences of Dental Trauma ...... 6 1.2 Prevention of Traumatic Dental Injuries ...... 7 1.3 Mouthguards ...... 9 1.3.1 History of Mouthguards in Sport ...... 9 1.3.2 Mode of Action: How Mouthguards Prevent Traumatic Dental Injuries ...... 10 1.4 Effectiveness of Mouthguards in Prevention of Traumatic Dental Injuries ...... 11 1.5 Mouthguards and Concussion ...... 12 1.6 Mouthguard Policies in Sport Worldwide ...... 13 1.6.1 Mouthguards in Sport: The Irish Context ...... 14 1.7 Knowledge and Attitudes Regarding the Management and Prevention of Traumatic Dental Injuries ...... 15 1.7.1 Knowledge and Awareness of Players Relating to Dental Trauma ...... 16 1.7.2 Players’ Knowledge of Trauma Prevention (Mouthguards) and Rates of Wear (Compliance) ...... 16 1.7.3 Coaches’ and Teachers’ Knowledge and Attitudes Relating to Dental Trauma Management and Prevention ...... 22 1.7.4 Parents’ Knowledge and Attitudes Relating to Dental Trauma Management and Prevention ...... 24 1.8 Knowledge of Irish Parents of Sports-Related Dental Injuries and Attitudes to Mouthguard Use ...... 26 1.9 Mouthguard Types ...... 29 1.10 Mouthguard Requirements ...... 31 1.10.1 Thickness and Extension of Labial Flange of Mouthguards ...... 32 1.10.2 Thickness and Extension of Palatal Flange of Mouthguards ...... 33 1.10.3 Occlusal Thickness and Balanced Occlusion ...... 33
VI 1.11 The Influence of Mouthguards on Normal Physiological Functions and Sports Performance ...... 34 1.11.1 Psychosocial Effects of Mouthguard Use in Sports ...... 36 1.12 Requirements for Mouthguard Materials ...... 37 1.12.1 Protective Qualities ...... 37 1.13 Materials used in the Fabrication of Mouthguards ...... 39 1.14 Materials Science: Stock and Mouth-formed Mouthguards ...... 39 1.15 Materials Science: Custom Mouthguards ...... 40 1.15.1 Custom Mouthguard Fabrication Techniques ...... 41 1.15.2 Machine Characteristics: Vacuum Forming ...... 42 1.15.3 Machine Characteristics: Pressure Forming ...... 43 1.15.4 Vacuum Forming vs. Pressure Forming: The Evidence ...... 43 1.15.5 Working Model Characteristics...... 44 1.15.6 Characteristics of EVA blanks ...... 46 1.15.7 Modifications to Optimise Thickness and Retention of EVA Custom Mouthguards 48 1.15.8 Modifications to Optimise Shock Absorption Performance of EVA Custom Mouthguards ...... 50 1.16 Mouthguard Deformation Over Time ...... 51 1.17 Mouthguards: Microbiological and Hygiene Considerations ...... 52 1.18 Orthodontic Patients, Children in the Mixed Dentition, and Mouthguards ...... 54 1.19 Which Mouthguard is best? – The Evidence...... 57 1.20 Concluding Remarks ...... 59 1.21 Introduction to current research study ...... 60 1.21.1 Aims ...... 60 1.21.2 Objectives ...... 60 1.21.3 Hypotheses...... 61
2 Chapter 2 Materials and Methods ...... 62 2.1 Ethical Approval and Relevant Permissions ...... 62 2.2 Study Design ...... 62 2.3 Study Population ...... 62 2.3.1 Inclusion and Exclusion Criteria ...... 62 2.3.2 Recruitment and Sampling ...... 63 2.4 Consent ...... 64 2.5 Parent and Child Questionnaires ...... 64 2.5.1 Pilot Parent Questionnaires...... 65 2.5.2 Completion of Parent and Child Questionnaires during Data Collection ...... 65 2.6 Assessment of Child’s Mouthguard and Dentition ...... 65 2.7 Equipment ...... 68 2.8 Training and Calibration Exercise ...... 69 2.9 Cross-Infection Control Procedures ...... 71 2.10 Data Collection Workflow ...... 72 2.10.1 Examiner Teams ...... 73
VII 2.10.2 Examining Stations ...... 73 2.11 Statistical Analysis ...... 76 2.11.1 Calibration ...... 77 2.11.2 Descriptive analysis ...... 77
3 Chapter 3 Results ...... 79 3.1 Calibration ...... 79 3.2 Characteristics of the sample ...... 80 3.2.1 Age ...... 81 3.2.2 Reported past trauma experience ...... 82 3.2.3 Signs of trauma...... 83 3.2.4 Incisal Overjet ...... 84 3.3 Sports participation, knowledge and behaviours in relation to mouthguard use ...... 84 3.3.1 Reported level of participation in sports ...... 84 3.3.2 Parent and child knowledge of mouthguard rules in sports besides Gaelic football 85 3.4 Player compliance with GAA mouthguard rules ...... 86 3.4.1 Parent-reported child compliance with rules ...... 86 3.4.2 Child-reported compliance with GAA mouthguard rules ...... 86 3.4.3 Factors influencing the rate of compliance with mouthguard wear for Gaelic football training ...... 87 3.5 Patterns of mouthguard wear for other sports ...... 91 3.6 Child and parent attitudes and behaviours in relation to mouthguard use ...... 92 3.6.1 Child attitudes and experiences ...... 92 3.6.2 Parent attitudes towards mouthguards ...... 94 3.6.3 Age of mouthguards being worn by the children ...... 96 3.6.4 Mouthguard hygiene: storage and cleaning ...... 97 3.7 Characteristics of Mouthguards worn by sample ...... 100 3.7.1 Types of mouthguards worn by participants ...... 100 3.7.2 Quality of mouthguards: Mouthguard Fit ...... 103 3.7.3 Quality of mouthguards worn: mouthguard thickness ...... 107
4 Chapter 4 Discussion ...... 111 4.1 Study Setting ...... 111 4.2 Methods and Calibration ...... 113 4.3 Sample Size...... 113 4.4 Questionnaires ...... 115 4.5 Characteristics of the sample ...... 116 4.6 Self-reported trauma experience ...... 117 4.7 Observed signs of traumatic dental injuries ...... 119 4.8 Incisal Overjet and Trauma ...... 120 4.9 Sports Participation ...... 120 4.10 Mouthguard rules and use in sports besides Gaelic football ...... 121 4.11 GAA Mouthguard Rules: Awareness and Compliance ...... 123
VIII 4.12 Child/Player Attitudes to the Use of Mouthguards in Sport ...... 128 4.13 Parent Knowledge and Attitudes to the Use of Mouthguards in Sports ...... 131 4.14 Mouthguard Care and Hygiene ...... 134 4.14.1 Mouthguard Storage ...... 134 4.14.2 Mouthguard Hygiene ...... 135 4.14.3 Mouthguard Age ...... 136 4.15 Mouthguard Quality Assessment ...... 137 4.15.1 Types of Mouthguards Worn by Children in this Sample ...... 137 4.15.2 Quality of Mouthguards Worn in a Sample of Children Playing Sport in Ireland: Mouthguard Fit ...... 139 4.15.3 Quality of Mouthguards Being Worn by Children Playing Sport in Ireland: Mouthguard Thickness ...... 144 4.16 Limitations of the study ...... 147 4.17 Conclusions ...... 153 4.17.1 Experience of Traumatic Dental Injuries Among Children in this Sample ...... 153 4.17.2 Compliance with GAA Mouthguard Rules ...... 153 4.17.3 Knowledge and Attitudes Relating to Mouthguard Use Among Parents and Children in this Sample ...... 154 4.17.4 Quality of Mouthguards worn by Children in this Sample ...... 154 4.17.5 Recommendations and Future Directions ...... 155
5 References ...... 157
6 Appendices ...... 174 6.1 Appendix 1: Letter of Ethical Approval ...... 174 6.2 Appendix 2: Letter of invitation to GAA & LGFA ...... 175 6.3 Appendix 3: Letter of Approval from GAA ...... 177 6.4 Appendix 4: LGFA Letter of Approval ...... 178 6.5 Appendix 5: Letter of Invitation to Individual GAA Clubs ...... 179 6.6 Appendix 6: Participant Information Leaflet – Parent ...... 181 6.7 Appendix 7: Participant Information Leaflet – Child ...... 184 6.8 Appendix 8: Consent Form – Parent ...... 186 6.9 Appendix 9: Consent Form – Child Participation ...... 187 6.10 Appendix 10: Parent Questionnaire ...... 189 6.11 Appendix 11: Child Questionnaire ...... 191 6.12 Appendix 12: Dentist Examination Sheet ...... 193 6.13 Appendix 13: Mouthguard Photographs...... 194 1. Stock MG – not fitting teeth; not covering labial surface of teeth; poor retention – need to bite to keep in place...... 194 2. Mouth formed MG. Bulky with ramp posteriorly. Unable to close lips...... 194 3. Stock MG: Surface roughness, poor hygiene ...... 194 4. Stock MG; Not fitting dentition; insufficient labial extension, poor retention, obvious deformation on right side, sharp borders with labial gingival blanching at tooth 22...... 194 5. Well adapted mouth-formed MG ...... 195
IX 6. Mouth formed MG – not adapted to fit teeth; surface integrity compromised - separation of layers; poor hygiene ...... 195 7. Mouth-formed MG – not adapted to teeth; not fitting dentition, not covering anterior teeth; poor retention and unable to close lips while in situ...... 195
X List of Tables
Table 1.1 Types of traumatic dental injuries ...... 3 Table 1.2 Frequencies of orofacial trauma in different sports ...... 5 Table 1.3 Mode of action of MG in preventing TDI (Sigurdsson and Cohenca, 2018) . 11 Table 1.4 Player knowledge of need for MG versus actual MG wear, per sport ...... 17 Table 1.5 Player-reported reasons for not wearing MG...... 22 Table 1.6 Findings of O’Malley et al. (2012) and Evans and O’Malley (2018) in relation to sports-related dental injuries (%) ...... 27 Table 1.7 Criteria for ideal mouthguard fabrication...... 31 Table 1.8 Variables affecting MG fabrication ...... 42 Table 2.1 Inclusion and exclusion criteria ...... 62 Table 2.2 Measurement locations on mouthguards ...... 66 Table 2.3 Mouthguards used for calibration exercise...... 69 Table 2.4 Detailed description of data collection workflow and data management ...... 75 Table 3.1 Inter-rater reliability for mouthguard thickness measurements ...... 79 Table 3.2 Intra-rater reliability measurements for labial and occlusal mouthguard thickness ...... 80 Table 3.3 Description of sample distribution, by club ...... 81 Table 3.4 Child and parent reports of past episodes of trauma to permanent teeth ... 82 Table 3.5 Child-reported signs of trauma compared to dentist-observed signs of trauma...... 83 Table 3.6 Level of sports participation among the sample ...... 84 Table 3.7 Level of sports participation, as a percentage of the total sample...... 85 Table 3.8 Proportion of players wearing and not wearing MG during Gaelic football training, according to age and gender ...... 87 Table 3.9 Binary logistic regression analysis investigating factors influencing player compliance with MG rules during Gaelic football training sessions...... 89 Table 3.10 Comparison of parent and child reports of MG wear for some versus all sports...... 91 Table 3.11 Chi-square analysis of association between mouthguard type, ability to speak and ability to breathe with whether the child likes or dislikes their MG...... 93 Table 3.12 Distribution of parents’ opinion on the protection afforded by various types of MG...... 94 Table 3.13 Linear Regression Analysis: Variables Influencing Price Parents Willing to Pay for Custom Mouthguard ...... 96 Table 3.14 Agreement between child- and parent-reported MG age ...... 97 Table 3.15 Agreement (훋) between parent and child answers relating to MG storage & hygiene ...... 100 Table 3.16 Parent report of mouthguard types worn by children compared to dentist identification of mouthguard type ...... 103 Table 3.17 Frequencies of fit-related characteristics of MG ...... 104 Table 3.18 Relationship between MG type and fit characteristics ...... 106 Table 3.19 Association between MG colour and MG retention...... 107 Table 3.20 Summary of MG thickness, per site (mean, median, standard deviation, interquartile range (IQR), and range) ...... 109 Table 3.21 Association between MG type and thickness ...... 110
XI
Table of Figures
Figure 1 Measurement locations on mouthguards ...... 67 Figure 2 Callipers used in this study ...... 68 Figure 3 Demonstration of calliper calibration using gauge block ...... 68 Figure 4 Laboratory prescription for inadequate mouthguards ...... 70 Figure 5 Calibration Mouthguards. (a) Ideal custom MG. (b) Non-ideal, dark custom MG. (c) Transparent custom MG. (d) Stock MG. (e) Mouth-formed MG...... 70 Figure 6 Equipment needed for data collection ...... 74 Figure 7 Data collection set up at GAA club ...... 74 Figure 8 Age distribution of study participants ...... 81 Figure 9 Boxplot of the data for the price parents were willing to pay for a custom mouthguard...... 95 Figure 10 Types of MG worn by participants as identified by dentists ...... 101 Figure 11 Distribution of who chose MG (%) ...... 101 Figure 12 Identification of MG type worn by children: dentist and parent reports (N) 103 Figure 13 Chart showing proportion of MG with fit-related features which are inadequate (brown) vs. adequate (light blue) ...... 105 Figure 14 Proportion of MG with adequate/inadequate retention, according to MG colour ...... 107 Figure 15 Boxplot showing range of MG thicknesses at each site ...... 110
XII 1 Chapter 1 Literature Review
1.1 Background – Dental Trauma
Dental trauma results in damage to teeth and other oral hard and soft tissues following an impact injury. These events may occur through falls in the home, impact injuries in road traffic accidents, violence, or through participation in contact sports (Andersson, 2013; Glendor, 2009; Lam, 2016). Dental trauma usually occurs suddenly and accidentally, is normally painful, and requires emergency dental management (Lam, 2016).
Traumatic dental injuries (TDI) do not allow for preparation of patients or dental staff and can therefore be upsetting and disruptive both for patients and the dental team (Lam, 2016). Future outcomes following TDI may be unpredictable at the time of initial presentation (Abbott and Salgado, 2014). Potential sequelae include pulp necrosis, inflammatory or replacement root resorption, and loss of the tooth
(Andreasen et al., 2006). These consequences can present many years post- trauma and frequently require extensive and costly treatment (Andersson, 2013).
1.1.1 Epidemiology of Dental Trauma
The oral cavity comprises just 1% of the total body area but injuries to the oral cavity make up 5% of traumatic injuries to the body as a whole (Andersson,
2013). Of these injuries, 92% are dental injuries, with 28% of these including injuries to the oral soft tissues (Andersson, 2013). Fractures to the maxilla or mandible occur in 5% of injuries to the head and neck (Andersson, 2013). Soft tissue injuries frequently coincide with injuries to the teeth (Andersson, 2013).
1 Dental injuries may occur in isolation or in combination, depending on the aetiology (Andersson, 2013).
Globally, it is estimated that over 1 billion people worldwide have suffered a TDI
(Petti et al., 2018). The prevalence of TDI is reported to be 6%-59% in the total population (Lam, 2016). Prevalence of TDI in the permanent dentition is approximately 15-20% among children and adolescents, with higher prevalence rates being reported in studies including adults (Andersson, 2013; Petti et al.,
2018). There are signs of incisor trauma in 25% of adults (Kaste et al., 1996).
Signs of TDI have also been observed in 25% of children (Qudeimat et al., 2019).
In Ireland, the last epidemiological survey of child oral health reported that signs of dental injury were observed in 19-22% of 12-15-year-olds (Whelton et al.,
2006). These trends have remained stable over many decades (Marcenes and
Murray, 2002).
The incidence of TDI is estimated as being 2.82 events per 100 people annually
(2.82%), with no significant difference between the primary and permanent dentitions (Petti et al., 2018). Males are more likely than females to suffer a TDI
(Petti et al., 2018).
There are many types of TDIs, varying in severity depending on the tissues involved and the type of injury sustained (Table 1.1) in both primary and permanent dentitions. Uncomplicated crown fractures are the most common injuries sustained in the permanent dentition (Andrade et al., 2010; Lam, 2016).
Unlike bony and soft tissue injuries, dental hard tissues cannot repair or regenerate themselves; up to three-quarters of dental injuries represent a permanent loss of dental hard tissue structure, thus requiring restoration (Lam,
2 2016). Luxation and avulsion injuries are rarer (Andrade et al., 2010); these involve injury to the pulp and supporting periodontal tissues.
Table 1.1 Types of traumatic dental injuries
Fractures Luxation injuries
Enamel fracture Concussion Enamel-dentine fracture (uncomplicated crown fracture) Subluxation Enamel-dentine-pulp fracture Lateral luxation (labial/palatal) (complicated crown fracture) Intrusive luxation (intrusion) Crown-root fracture Extrusive luxation (extrusion) Root fracture Avulsion Alveolar fracture
The maxillary central incisors are most commonly affected by TDI in both primary and permanent dentitions (Lam, 2016). An increased overjet is a risk factor for trauma in both primary and permanent dentitions (Born et al., 2019; Norton and
O’Connell, 2012). In the permanent dentition, incisal overjet measurements of greater than 6mm have been reported to be associated with greater risk of trauma
(Årtun et al., 2005; Brin et al., 2000; Burden, 1995; Sgan-Cohen et al., 2005).
Silva Oliveira et al. (2018) reported a significant association between overjet measurements of 3.0mm or greater and TDI. Artun et al. (2005) reported that children with incisor overjet measurements of greater than 9.5mm were 3.7 times more likely to suffer incisor trauma compared to children with normal overjet; similarly, children with overjet measurements of 6.5-9.5mm were 2.8 times more likely to suffer incisor trauma. An association between incompetent lips and greater risk of trauma has also been reported as a significant predictive factor for
3 TDI risk; this may be due to its relationship with increased overjet (Årtun et al.,
2005; Burden, 1995).
A previous history of trauma is also a risk indicator. Ramos-Jorge et al. (2008) reported that adolescents who had previously sustained dental trauma were 4.85 times more likely to experience further dental trauma in comparison to a control group of adolescents who had not experienced trauma before.
1.1.2 Sports-Related Dental Injuries
Participation in sports is an important means of enhancing overall health and wellbeing. However, injuries can happen, particularly through participation in contact sports. The US Surgeon General’s report on oral health described sports as a leading cause of injuries to the craniofacial complex (U.S. Department of
Health and Human Services, 2000). Sports-related dental injuries (SRDI) represent 10-39% of all dental injuries in children (Newsome et al., 2001). An audit carried out in an emergency dental department in Ireland found that 23% of all children attending with trauma had sustained their injuries whilst playing sports
(Stewart et al., 2011).
The frequency of dental trauma reportedly varies among different sports (Table
1.2). Trauma to the orofacial structures while playing sports may occur due to collision with another player or a piece of sporting equipment or may be caused by a fall (Delilbasi et al., 2004).
4 Table 1.2 Frequencies of orofacial trauma in different sports
Sport Rate of dental injuries Football 67 injuries/10,000 players over 2 years Sane (1988) Handball 50.2 injuries/10,000 players over 7 years Soccer 19.4 injuries/10,000 players Australia 42.3% prevalence Chapman and Ireland 26.9% prevalence Rugby Nasser (1993) Scotland 50% prevalence Wales 54.2% prevalence Yamada et al. Soccer 32.3% prevalence (1998) Rugby 56.5% prevalence Cumulative incidence: Pieter and Taekwondo 6.1 injuries/1000 men Zemper (1999) 4.55 injuries/1000 women Maladière et al. Soccer 25% (2001) Rugby 15% Ice Hockey 11.5% prevalence Handball 37.1% Ferrari et al. Martial arts 32.1% (2002) Soccer 23.1% Basketball 6.4% Incidence over 1 year: Labella et al. Basketball 1.2 injuries/10,000 players wearing MG (2002) 6.7 injuries/10,000 players not wearing MG Girls’ field hockey 3.9 injuries/100,000 athletic exposures (AE) Collins et al. Boys’ basketball 2.6 injuries/100,000 AE (2016) Boys’ baseball 1.5 injuries/100,000 AE Boys’ wrestling 1.4 injuries/100,000 AE Water polo 10.2% prevalence Galic et al. Karate 6.9% prevalence (2018) Taekwondo 3.5% prevalence Handball 9.1% prevalence Qudeimat et al. Soccer 11% prevalence (2019) Bruggesser et Judo 42.9% prevalence of orofacial injuries al. (2020) Polmann et al. 30% pooled prevalence among combat sports, (2020) Combat Sports with jiu-jitsu displaying the highest prevalence of trauma (52.9%)
5 1.1.3 Consequences of Dental Trauma 1.1.3.1 Quality of Life: Psychosocial Impact of Traumatic Dental Injuries
Traumatic dental injuries and their management can cause pain and anxiety and there may be considerable functional and aesthetic concerns, particularly if the injury has resulted in pulp necrosis, replacement root resorption and tooth infraposition, or loss of a permanent anterior tooth (Zaror et al., 2018).
A recent systematic review examined the quality of life effects of TDI on children aged between 1 and 15 years (Zaror et al., 2018). Though there is some heterogeneity in the literature, following meta-analysis, it was reported that school-aged children who have suffered a TDI were found to be 31% more likely to report a negative impact on OHRQoL compared with children with no previous history of a TDI (Zaror et al., 2018). The same study reported an association between greater severity of TDI and greater negative impact on OHRQoL among school children (Zaror et al., 2018). The emotional and social well-being domains of OHRQoL have been found to be particularly affected among schoolchildren who suffered severe TDI (Freire-Maia et al., 2015; Zaror et al., 2018).
There seems to be an association between TDI and reduced OHRQoL in preschool aged children, according to two recent systematic reviews (Borges et al., 2017; Zaror et al., 2018). Similar to school-aged children, complex TDI have
53% greater chance of impacting OHRQoL than uncomplicated TDI, and 58% greater chance of affecting OHRQoL than controls (Borges et al., 2017).
1.1.3.2 Economics of Traumatic Dental Injuries
Treatment of teeth affected by TDI may be needed throughout the individual’s lifetime; TDI may be associated with a lifetime economic burden (Nguyen et al.,
6 2004). Management of TDI therefore represents a significant public dental health cost.
Studies investigating the direct and indirect costs associated with TDI identify that the main predictors of cost are TDI severity and access to care, with complicated
TDI’s being more expensive in the long-term (Bani‐Hani et al., 2020; Glendor et al., 2008). Bani-Hani et al. (2020) reported that the average cost of treating a complex dental injury within the first year alone was €1613.30. Prevention of dental injuries could result in notable reduction in costs to public dental services, insurance companies, and individuals.
1.2 Prevention of Traumatic Dental Injuries
Given the prevalence of dental trauma and the associated psychological, aesthetic, social and financial implications, it is prudent to consider means of preventing such injuries, where possible. Principles for prevention of TDI encompass education, early correction of increased overjet, and the use of protective devices (Sigurdsson and Cohenca, 2018).
Early orthodontic treatment to reduce incisal overjet greater than 6.5mm may decrease the overall risk of trauma for these children; this may also have the added benefit of correcting any lip incompetence (Brin et al., 2000; Burden, 1995;
Cohenca et al., 2007). Early orthodontic treatment may not be appropriate for a variety of reasons, including financial limitations (Sgan-Cohen et al., 2005)
Injury prevention through educating individuals in personal protection is common in society, for example through the use of child safety seats in cars, or the use of bicycle helmets during cycling. Several contact sports worldwide are leading the field in protection against TDI through the use of protective devices such as
7 mouthguards or facemasks to prevent sports-related traumatic dental injuries
(Ferrari et al., 2002). Education of patients, parents, teachers and sports coaches on the risks of TDI, as well as immediate emergency management measures, may help to prevent TDI and to improve the prognosis of any TDI which do occur
(Sigurdsson and Cohenca, 2018). Not all TDI can be prevented, as some are caused by falls, road traffic accidents and interpersonal violence (Lam, 2016).
The dental community have an important public dental health role to play in raising awareness on these issues among parents, players, coaches and other medical professionals (Al Sari et al., 2019; Bracho Pacheco et al., 2018; Levin and Zadik, 2012; Razeghi et al., 2019). The International Association for Dental
Traumatology (IADT) supports dental professionals in this role through their
“Save A Tooth” poster campaign as well as the publicly-available free “Tooth
SOS” mobile application available for Android, iOS and through the IADT website at https://www.iadt-dentaltrauma.org (International Association for Dental
Traumatology, 2020).
High-risk contact sports organisations have responded to the high level of injuries by mandating use of personal protective equipment such as face shields and mouthguards to prevent oral injuries (Sigurdsson, 2013). Face shields consist of a metal cage with a clear plastic shield attached to a helmet, and are worn in contact sports such as ice hockey to protect the player from injury to their facial bones and soft tissues (Sigurdsson and Cohenca, 2018).
Mouthguards are the most widely used personal protective equipment in sports and are always recommended after a TDI to prevent re-injury. For the purposes of this study, this literature review will focus on the use of mouthguards in sporting activities for the prevention of TDI in permanent dentition.
8 1.3 Mouthguards
A mouthguard is “a resilient device or appliance placed inside the mouth to reduce oral injuries, particularly to teeth and surrounding structures” (Newsome et al., 2001). Mouthguards (MG) are typically made for the maxillary arch because the maxillary central incisors are the teeth at greatest risk of TDI (Takeda et al.,
2008). Mandibular and bimaxillary MG have also been described but are far less frequently utilised (Milward and Jagger, 1995; Takeda et al., 2014).
There are 3 types of MG available. Stock MG (SMG) are available in several predetermined sizes and cannot be adjusted to fit (Sigurdsson, 2013). Mouth- formed MG (MFMG) are made of a thermoplastic material which can be heated in boiling water and moulded to fit the individual’s dentition (Sigurdsson, 2013).
Custom MG (CMG) are fabricated from a cast model of an impression of the person’s teeth made by a dentist (Sigurdsson, 2013).
1.3.1 History of Mouthguards in Sport
A 2013 review publication has summarised the history of MG use in sports
(Sigurdsson, 2013). The earliest documented use of tooth protection in sports was in the late 19th and early 20th centuries among boxers, where strips of gutta percha were placed against the teeth to protect them from injury (Sigurdsson,
2013). Reusable MG made from vella rubber were developed in the early 20th century and were first allowed in boxing matches in 1928. In the aftermath of
World War II, articles in the dental literature began to appear in relation to injuries sustained in American football; rules regarding the use of headgear and MG in high school American football first appeared in 1962 and were eventually adopted for college football in 1974 by the NCAA. At the time, a 48% reduction in trauma
9 incidence was reported in this sport; however, it was difficult to establish if this was due to the use of MG because better helmets and face guards were introduced at the same time as well as more stringent rules in relation to inter- player contact (Sigurdsson, 2013).
From the initial introduction of MG rules for American football to the present day, more and more professional and amateur sporting organisations across the world have implemented mandatory MG rules. Mouthguards are also recommended by countless professional dental organisations (including but not limited to the
International Association of Dental Traumatology, American Dental Association,
American Academy of Pediatric Dentistry, British Dental Association, and
International Academy of Sports Dentistry).
1.3.2 Mode of Action: How Mouthguards Prevent Traumatic Dental Injuries
Dental injuries are caused by pressure exerted by an applied force on the dental hard and soft tissues, and extent of damage is proportional to the force and direction of impact (Andersson et al., 2019). Mouthguards covering the teeth and gingivae increase the surface area over which the impact force of the injury may be applied, thus dissipating the forces and reducing the pressure exerted on any one tooth (Hoffmann et al., 1999). While MG cannot completely prevent any traumatic injuries, they do mitigate some of the force applied to the teeth (Table 1.3).
10 Table 1.3 Mode of action of MG in preventing TDI (Sigurdsson and Cohenca, 2018)
Trauma type Mechanism of protection by MG
Tooth luxation and fracture Separate maxillary and mandibular arches
Absorb and redistribute impact force(s)
Soft tissue bruising and laceration Separate teeth and soft tissues
Absorb and redistribute impact force(s)
Mandibular fracture Absorb and redistribute impact force(s)
Stabilisation of mandible during traumatic jaw closure
Concussion Absorb and redistribute impact force(s) to prevent transmission through cranium to brain
1.4 Effectiveness of Mouthguards in Prevention of Traumatic
Dental Injuries
Research objectively measuring MG effectiveness would require in vivo research with live subjects; such research would be unethical by exposing participants to the real risk of TDI (Knapik et al., 2007). To date, there are no randomised clinical trials investigating the effectiveness of the various different MG types in preventing TDI. Much of the evidence relating to the effectiveness of MG in actual
TDI prevention through shock absorption comes from in vitro research using artificial or cadaver skulls and tooth models in laboratory impact studies
(Bemelmanns and Pfeiffer, 2001; Greasley et al., 1998; Knapik et al., 2007).
These studies frequently display significant variation in methodology.
The findings of a laboratory impact study suggest that, by wearing MG, players would be expected to experience lower numbers of fractured teeth than if they were not wearing a MG (Greasley and Karet, 1997). A study carried out using
11 sheep maxillae reported that a greater force would be needed to actually fracture teeth in the event of a TDI when wearing a MG than if there were no MG
(Johnston and Messer, 1996),
The extent of protection afforded by MG has been reported in various sports.
Cohenca et al. (2007) compared the rate of TDI between basketball players (not required to wear MG) and American football players (required to wear MG) and reported that basketball players had a five times greater risk of sustaining a TDI.
Labella et al. (2002) reported that, among college basketball players, MG users experienced significantly lower rates of TDI and required fewer dental visits than non-users. A recent systematic review and meta-analysis found that sportspeople who wear a MG are 93% less likely to suffer TDI (Fernandes et al., 2019); however, the significant heterogeneity of included studies was a limitation of this analysis. Knapik et al. (2019) concluded through their meta-analysis that MG
“offer significant protection from orofacial injuries", Overall, the literature indicates that there is a reduction in incidence and severity of TDI through the use of MG
(Fernandes et al., 2019; Knapik et al., 2019, 2007; Labella et al., 2002).
1.5 Mouthguards and Concussion
Concussion is defined as “a subset of mild traumatic brain injury (TBI) which is a complex pathophysiological process affecting the brain, induced by biomechanical forces” (McCrory et al., 2013). There has been some in vitro evidence that MG allow for a reduction in cranial bone deformation, intracranial pressure and head acceleration, thus reducing the risk of concussion (Hickey et al., 1967; Takeda et al., 2005). Benson et al. (2009) postulate that, while wearing
MG may not provide a significant difference in the incidence of concussion, it may
12 reduce severity of symptoms. Emery et al. (2017) reported an 86% increase in concussion risk amongst those who do not wear MG, but this finding was not statistically significant. The role of MG in protecting against or preventing concussion in contact sports is controversial and needs further investigation.
1.6 Mouthguard Policies in Sport Worldwide
Several sporting organisations around the world have policies and rules for the wearing of MG. In the USA, MG have been mandatory in high school football since the 1960s (Sigurdsson, 2013). In high school sports, “properly fitted” MG are required for lacrosse, football, ice hockey, field hockey, and for wrestlers wearing orthodontic appliances (National Federation of State High School
Associations Sports Medicine Advisory Committee, 2018). A “properly fitted mouthguard” is defined for high schools as one that covers all maxillary teeth, separating the maxillary and mandibular teeth, and protecting the teeth and supporting bone and soft tissues (National Federation of State High School
Associations Sports Medicine Advisory Committee, 2018). Custom MG and
MFMG are said to fulfil the criteria of appropriate fit (National Federation of State
High School Associations Sports Medicine Advisory Committee, 2018).
At college level, the National Collegiate Athletic Association (NCAA) has implemented rules for mandatory MG use for all those playing lacrosse and football, and for wrestlers who have orthodontic appliances in place (National
Collegiate Athletic Association, 2019a, 2019b, 2019c, 2018). Penalties such as a
“time-out” result from non-compliance with these rules. Mouthguards are
“recommended” by the NCAA for ice hockey, but are not mandatory according to their rule book (National Collegiate Athletic Association, 2019d). The NCAA does
13 not have any rules for the use of MG in any other sports under their governance
(basketball, baseball, bowling, water polo, soccer and volleyball) (National
Collegiate Athletic Association, 2020). Field hockey is governed by the
International Hockey Federation (FIH); in their rules, it is “recommended to wear shin, ankle and mouth protection”, but this is not mandatory (The International
Hockey Federation, 2018). At a professional level, MG are not required for either ice hockey or football in the USA.
Rugby is a contact sport which carries significant risk of injury to the head and neck. According to the laws of rugby, players are “permitted” wear a protective
MG, but it is not required (World Rugby, 2020). New Zealand is the only country that has mandatory MG rules (Broad and Welbury, 2015). There are no rules for the use of MG in soccer (Fédération Interationale de Football Association, 2015).
Boxing is another high-impact contact sport; however, the rules of boxing state that a “properly fitted gumshield” is not only mandatory, but participants must bring two such appliances to each contest (British Boxing Board of Control,
2020). Mouthguards are also required in the practice of mixed martial arts
(Association of Boxing Commissions and Combative Sports, 2018). No regulations on the use of MG could be found for other grappling sports such as judo or jiu jitsu.
1.6.1 Mouthguards in Sport: The Irish Context
The Irish Dental Association (IDA) issued a position statement in 2013 recommending that MG be worn in “organized activities that carry a risk of orofacial injury”. Mouthguards should fit properly and, in the case of growing children especially, should be checked periodically and have the fit adjusted as needed to ensure appropriate protection (Irish Dental Association, 2013).
14 In 2014, the Gaelic Athletic Association (GAA) issued mandatory rules requiring the use of MG for players of all levels during training sessions and matches (Rule
4.3, Gaelic Athletic Association, 2019). The Ladies’ Gaelic Football Association is also covered by these rules (Ladies Gaelic Football Association, 2013). Their policy states that is the player’s responsibility to ensure they wear their MG; in the case of minors, it is the parent’s responsibility (Gaelic Athletic Association,
2016). Failure to wear a MG is said to result in the player in question being sent off in a game (Gaelic Athletic Association, 2016). Additionally, should a player suffer a dental injury whilst playing without a MG, they are not eligible for cover under the GAA Injury Benefit Scheme (Gaelic Athletic Association, 2016).
The GAA require MG to be “properly fitted”, and state that CMG are most likely to fulfil this criterion. Nevertheless, the choice of MG is left to player preference, as long as the device chosen carries the CE mark for quality assurance, and the player feels that the MG fits properly (Gaelic Athletic Association, 2016).
Since the introduction of these rules, the GAA have reported a reduction of 37% in claims to the GAA Injury Benefit Fund relating to dental injuries among minor age groups, and a reduction of 39% in adult grades (Gaelic Athletic Association,
2016).
1.7 Knowledge and Attitudes Regarding the Management and
Prevention of Traumatic Dental Injuries
Individual behaviour is influenced by a person’s knowledge and attitudes, particularly in relation to the use of protective equipment in sports (Braham et al.,
2004).
15 1.7.1 Knowledge and Awareness of Players Relating to Dental Trauma
The level of knowledge in relation to dental trauma varies among players, and between different sports. Galic et al. (2018) reported that, though 98.7% of players were aware of the risk of dental trauma, over half of the athletes studied in four different sports (water polo, karate, taekwondo and handball) were “poorly informed” in relation to emergency management of such injuries. Only one-third of their sample were aware that an avulsed tooth could be replanted (Galic et al.,
2018). Similarly, a cross-sectional study of adult amateur soccer players showed that only 19% of players knew what to do immediately after an avulsion injury
(Dursun et al., 2015). Ilia et al. (2014) reported that, in spite of a high prevalence of orofacial injury among rugby union players, over half of injured players did not seek any assessment after injury, and only 20% sought treatment from a dentist.
In taekwondo athletes, 83% of participants were aware of the risk of dental injury and 90% of them were aware of a need for prompt management of such injuries
(Aljohani et al., 2017). Despite this high level of knowledge, the study reported that only half of those who had sustained orofacial injuries had sought treatment, and only 12% knew that an avulsed tooth could be replanted (Aljohani et al.,
2017).
1.7.2 Players’ Knowledge of Trauma Prevention (Mouthguards) and Rates
of Wear (Compliance)
Frequently, a disparity exists between the level of awareness and the level of wear (Table 1.4); while players know MG protect against dental injury, they do not necessarily put this into practice (Frontera et al., 2011).
16 Table 1.4 Player knowledge of need for MG versus actual MG wear, per sport
Awareness Rate of MG Author Sport(s) studied of MG (%) wear (%)
Çaglar et al (2005) 62% 24% Ice hockey
Aljohani et al (2017) 81% 56% Taekwondo
Tulunoglu and 100% 97.8% Boxing Özbek (2006) 71% 35.7% Taekwondo
Water polo, karate, taekwondo, Galic et al (2018) 97.3% 41% handball
Bergman et al 67% 28% Handball (2017)
Collins et al (2015) 77% 12.3% Basketball, baseball, softball
Frontera et al (2011) 65% 7% Basketball
Dursun et al (2015) 22% 2.9% Amateur soccer
Ilia et al (2014) 97% 76.9% Rugby (Australia)
Liew et al (2014) 88% 9.2% Rugby (Malaysia)
Attitudes towards and use of MG appears to be influenced by several factors.
1.7.2.1 Past History of Dental Trauma
Those who have suffered a previous dental injury have been reported to be more likely to wear a MG while playing sports (Çaglar et al., 2005; Frontera et al., 2011;
Galic et al., 2018; Ilia et al., 2014; Vucic et al., 2016b). Çaglar et al. (2005) reported that adult ice hockey players with a past history of dental injury were over twice as likely to wear a MG than their injury-free counterparts (36.5% (N =
4/11) versus 15.3% (N = 4/26) respectively). It is unclear whether those with a history of TDI were advised to wear MG by their dentist after the injury; Çaglar et al. (2005) reported that only 4 subjects stated that they had received advice on injury prevention, but did not specify whether these were the same 4 players that had suffered TDI in the past.
17 Galic et al. (2018) reported that ten times more players with no past history of trauma believed that MG were unnecessary for prevention of TDI, than those with a history of trauma (44.4% versus 4.4% respectively). Despite this, only 41% of their total sample reported actually wearing MG regularly; rates of MG wear among those with and without a history of TDI were not reported (Galic et al.,
2018).
1.7.2.2 Competitive Level and Mouthguard Use
The level at which the team is playing (i.e. juvenile, amateur, elite) also appears to influence the likelihood of wearing MG (Banky and McCrory, 1999; Hawn et al., 2002; Vucic et al., 2016b). Banky and McCrory (1999) found that the level of
MG use was consistently lower among junior rugby players than both sub-elite and elite players, for matches and at training. Elite rugby players had the highest compliance rates in MG wear (Banky and McCrory, 1999). Conversely, studies in both ice hockey and field hockey have reported different outcomes. Hawn et al. (2002) found that, according to a survey of NCAA ice hockey coaches, elite players (Division I) were significantly less likely to wear their MG than players in
Division II or III. Similar trends were observed among field hockey players. Vucic et al. (2016b) reported that 55.4% of elite field hockey players felt MG were unnecessary, compared to 33.9% of non-elite players, implying that non-elite players had more positive attitudes towards MG.
1.7.2.3 Mouthguard Rules and Compliance
Implementation of rules for MG wear in sport, with penalties for non-use, has been reported to improve rates of wear (Collins et al., 2015). Regulations requiring the use of MG for players at all levels during matches were implemented for rugby in New Zealand in 1997-1998 (Quarrie et al., 2005). Introduction of
18 these rules resulted in a significant increase in the use of MG in rugby players in
New Zealand, from 67% in 1993 to 95% (during competition) in 2003 (Quarrie et al., 2005).
1.7.2.4 Mouthguard Use for Training versus Competition
It has also been widely reported that rates of MG wear differ greatly between training days and competition days. In general, players tend to be less likely to wear MG during training sessions, and these differences tend to be significant
(Banky and McCrory, 1999; Braham et al., 2004; Ilia et al., 2014; Kroon et al.,
2016). Ilia et al. (2014) reported that, while 76.9% of their total sample of 225
Australian rugby union players wore MG, 57% of them wore them during competition only, and 41.6% wore them for both training sessions and matches.
Another study conducted among Australian rugby players also found a similar rate of MG wear during games of 49.75% (Kroon et al., 2016). This may be due to a perception of training sessions involving a possible lower risk of injury due to a lower contact level, despite spending a larger proportion of time in training compared to in competition (Ilia et al., 2014).
1.7.2.5 Player Age and Mouthguard Use
Age appears to influence compliance with MG wear. Younger children are less likely to wear MG compared to adolescents and adult sportspeople (Banky and
McCrory, 1999; Boffano et al., 2012; Kroon et al., 2016; Liew et al., 2014; Matalon et al., 2008; Zamora-Olave et al., 2018). Among a sample of junior rugby players,
54.5% of those under age 8 were found to be wearing MG compared to 73.9% of those under age 15 (Kroon et al., 2016). Boffano et al. (2012) reported that younger rugby players (under 22 years) were 3.5 times less likely to wear MG than those over the age of 22, and this association was statistically significant.
19 Matalon et al. (2008) conducted a research study among children attending a student clinic at a university dental hospital in a diverse population with no common background in a specific sport. They reported a significant correlation between younger age and loss of MG at one year. Males were significantly more likely to wear MG than females (Matalon et al., 2008).
1.7.2.6 Personality Trait Characteristics and Mouthguard Use
Intrinsic personality traits may also play a role in the likelihood of a person wearing a MG for sports. Collins et al. (2015) conducted a large study of 1636 high school (adolescent) athletes playing basketball and baseball/softball whereby their MG use was investigated in relation to characteristics of impulsivity
(impulsive delay discounting) and precaution adoption process modelling. They reported that players who were more impulsive were less likely to wear MG and concluded that rules and penalties would be the only way to ensure a high level of adolescent compliance with MG rules (Collins et al., 2015).
1.7.2.7 The Effect of Dental Professional Advice and Mouthguard Use
Dental professional advice on the need for MG during sports activities has been found to significantly increase the rate of MG wear (Bergman et al., 2017;
Frontera et al., 2011). Bergman et al. (2017) reported that, of the percentage of handballers who were wearing MG, over three-quarters (76.9%) of these had been advised to do so by a dental health professional. A similar finding was observed by Frontera et al. (2011), with 74.1% of those wearing MG for basketball having been told to do by their dentist. Additionally, 47.4% of the total sample had been educated by their dentist about MG, and on what to do in the event of a dental traumatic injury (Frontera et al., 2011). These findings serve to highlight the important role dental professionals have in raising awareness and educating
20 sportspeople and their parents and coaches on how to prevent dental injury, especially through the use of MG. It is also usual for dentists to provide specific advice regarding the need for wearing MG after incidents of TDI, so that their patients are aware that MG will help protect their teeth in the event of a future injury.
1.7.2.8 Player-Reported Reasons for Not Wearing Mouthguards
There are numerous reasons reported by players for not wearing MG in spite of relatively high levels of awareness in relation to the benefits (Table 1.5). The most commonly reported reasons are perceived absence of a need for MG, discomfort associated with wearing MG, and difficulty with normal oral functions such as speech and swallowing (Table 1.5). These are all self-reported subjective measures. Additionally, players frequently wear MG only for the sports which have rules and policies requiring the use of MG, and do not wear them for other contact sports where MG use is optional (Collins et al., 2016).
21 Table 1.5 Player-reported reasons for not wearing MG.
Reason Supporting evidence
Aljohani et al. (2017), Bergman et al. (2017), Braham et al. Not necessary/not required (2003), Collins et al. (2015), Galic et al. (2018), Kroon et al. (2016), Razzak et al. (2019)
Aljohani et al. (2017), Bergman et al. (2017), Braham et al. Discomfort (2003), Galic et al. (2018), Lee et al. (2013), Matalon et al. (2008), Walker et al. (2002)
Boffano et al. (2012), Braham et al. (2003), Collins et al. Speech problems (2015), Ilia et al. (2014), Lee et al. (2013), Walker et al. (2002)
Boffano et al. (2012), Braham et al. (2003), Collins et al. Breathing problems (2015), Galic et al. (2018), Ilia et al. (2014), Lee et al. (2013), Tanaka et al. (2015), Walker et al. (2002)
Lack of information/not Aljohani et al. (2017), Bergman et al. (2017) being told to
Swallowing problems Boffano et al. (2012), Lee et al. (2013),
Poor fit Boffano et al. (2012), Ilia et al. (2014), Walker et al. (2002)
Braham et al. (2003), Razzak et al. (2019), Walker et al. Dislike wearing it (2002)
Perceived restricted Braham et al. (2003), Lee et al. (2013), Walker et al. (2002) athletic performance
Gagging/nausea Ilia et al. (2014), Lee et al. (2013)
Cost Kroon et al. (2016), Zamora-Olave et al. (2018)
Embarrassment Matalon et al. (2008)
1.7.3 Coaches’ and Teachers’ Knowledge and Attitudes Relating to
Dental Trauma Management and Prevention
It appears, from the literature, that sports coaches’ knowledge with regard to dental trauma management needs improvement. In a survey-based study, only half of basketball coaches knew that avulsed teeth could be replanted, but the majority knew that emergency dental treatment would be needed for traumatised teeth (Perunski et al., 2005). Similar trends were reported among rugby coaches, with only 40.6% of coaches being aware of the time-dependent urgency of
22 replanting an avulsed tooth, and 43.8% reporting that this could only be done by a dentist (Kroon et al., 2016).
It appears that the majority of coaches are aware of the importance of wearing
MG to prevent dental injury (Hawn et al., 2002; Kroon et al., 2016). Additionally, three out of four coaches reported that they had someone on their team whose responsibility was to ensure that MG rules were enforced, though few penalties for non-compliance were actually issued during games (Hawn et al., 2002). Kroon et al. (2016) reported that 93.7% of junior rugby league coaches promoted the use of MG and 75% of these recommended CMG. A qualitative study which included trainers among focus groups highlighted their role in conveying the importance of MG to young participants (Glendor, 2013; Glendor and Göransson,
2013).
Children spend a lot of their time at school and injuries frequently happen in the playground or during school sporting activities (Tewari et al., 2020). Baseline teachers’ knowledge relating to TDI has been reportedly low (Arikan and
Sönmez, 2012; Feldens et al., 2010; Marcano-Caldera et al., 2018; Young et al.,
2013). A recent systematic review identified that much of the research in this area has been carried out in developing countries; results may not be fully generalisable to Western societies (Tewari et al., 2020). It has been reported that the majority of teachers have not had any training in dental first aid (Feldens et al., 2010; Marcano-Caldera et al., 2018; Tewari et al., 2020). Most teachers are reportedly not confident in how to manage a TDI (Feldens et al., 2010; Marcano-
Caldera et al., 2018; Tewari et al., 2020). However, despite a low level of knowledge, a willingness among teachers to undergo dental first aid training has been reported (Marcano-Caldera et al., 2018). Educating teachers on
23 management and prevention of TDI through the use of leaflets and posters improves knowledge levels (Arikan and Sönmez, 2012; Young et al., 2013).
1.7.4 Parents’ Knowledge and Attitudes Relating to Dental Trauma
Management and Prevention
Knowledge and awareness of the management and prevention of TDI in the community is variable, especially among parents. The International Association for Dental Traumatology (IADT) have recognised this gap in knowledge and have provided free resources globally targeted to lay persons (parents, sports coaches and teachers) to improve knowledge and awareness of dental trauma via the
“Save a Tooth” poster (available in 21 languages) and the free “Tooth SOS” mobile application available on both Android and iOS operating systems
(www.iadt-dentaltrauma.org (International Association for Dental Traumatology,
2020)).
The setting of studies investigating parent knowledge may be influenced by cultural and societal factors and results may not be generalisable. Hegde et al.
(2010) reported that 68.2% of their sample of mothers in India were aware of how to manage a dental injury, independent of whether or not the mother worked outside the home. Working mothers were significantly more aware of the need for MG than non-working mothers (Hegde et al., 2010). In Iraq, 90% of mothers had little to no knowledge of dental trauma management, independent of any sociodemographic factors or maternal educational level (Yassen et al., 2013).
Only 9% of the sample were aware of the need for MG for trauma prevention; those with a higher level of education and/or mothers in employment demonstrated a greater awareness of trauma prevention through the use of MG
(Yassen et al., 2013).
24 An American study reported that 47% of participating parents knew an avulsed tooth could be replanted; only 40% would transport such a tooth in liquid and 25% would transport it in milk (Vergotine and Koerber, 2010). Parents of children attending on recall visits was significantly better than parents of first attenders, thus emphasising the importance of dentists educating parents and the general public regarding TDI (Vergotine and Koerber, 2010). In Italy, half of parents surveyed stated that they knew what to do if their child suffered a TDI; awareness that avulsed teeth could be replanted was high, and most stated that emergency dental treatment is required within 30 minutes (Quaranta et al., 2016). Improved knowledge was observed among participants with higher education levels
(Quaranta et al., 2016). Mouthguard use was also investigated and 62.9% of parents reported that their child was using a MG (Quaranta et al., 2016), which was greater than awareness of MG use among mothers in Iraq (Yassen et al.,
2013).
1.7.4.1 Cost of Mouthguards
Cost may be a barrier to MG provision. Matalon et al. (2008) reported that 20.8% of parents had not given their child a MG before the study due to the expense.
Cost was also reported by parents surveyed by O’Malley et al. (2012) as a reason for their children not having a MG.
The price that parents were willing to pay for a CMG was investigated by several studies. Khodaee et al. (2011) reported that parents were willing to spend on average $50.00 on safety equipment, yet there was only moderate parent support
(53.8%) for mandatory MG rules in soccer. Only 55.5% of parents would ensure their child used MG if it were supplied free-of-charge by the soccer league, even though 80% of parents believed that MG protect against dental injury (Khodaee
25 et al., 2011). Similarly, another study found that all included parents believed that
MG should be worn for any activity where there would be a risk of trauma; despite this, none of them were willing to pay more than $25.00 for a dentist-made CMG
(Walker et al., 2002). Less than a quarter of the sample would pay as much as
$25.00; most of them wanted to pay less than that for a CMG (Walker et al.,
2002). These findings highlight the fact that cost of MG is likely to be a significant factor for parents in deciding whether to buy a MG for their children, and which type they would invest in. It may also influence their attitude to MG replacement when damaged or no longer fitting appropriately in actively growing children.
1.8 Knowledge of Irish Parents of Sports-Related Dental
Injuries and Attitudes to Mouthguard Use
Evidence relating to Irish parents’ knowledge of SRDI and the use of MG comes from two cross-sectional questionnaire-based studies carried out among parents of 9-13-year-old primary school students in the West of Ireland (Table 1.6). Both studies utilised a convenience sampling method whereby a series of primary schools across 10 counties were randomly selected, and questionnaires were sent home from school with all children in fourth, fifth and sixth classes (the three oldest classes) for their parents to complete. The questionnaires comprised questions relating to child sports participation, MG wear during sports, and any history of trauma over the previous year (Evans and O’Malley, 2018; O’Malley et al., 2012).
O’Malley et al. (2012) reported a response rate of 45.45% (1,111 questionnaires were sent home from school to parents, and 505 were returned). The results were reported using descriptive and comparative statistics; no regression analyses
26 were performed. The response rate was not reported by Evans & O’Malley
(2018); 298 parents returned completed questionnaires for completion in the study. Results were presented as descriptive statistics only, with no comparative or regression analyses completed.
In 2012 it was reported that 10% of children in their sample (5-17-year-olds) had suffered some type of injury while playing sports; 52% of these were reported to be dental injuries, corresponding to 5.2% of the entire sample (O’Malley et al.,
2012). A follow up study carried out in a similar population reported a lower annual incidence of dental injuries (15% overall, with 15% of these relating to sports) (Evans and O’Malley, 2018). The authors theorise that this is due to a greater uptake of MG wear among the sample than the earlier study (Evans and
O’Malley, 2018; O’Malley et al., 2012).
Table 1.6 Findings of O’Malley et al. (2012) and Evans and O’Malley (2018) in relation to sports-related dental injuries (%)
Evans and O’Malley O’Malley et al. (2012) (2018)
Sample size N = 505 N = 298
Gender
• Male 53% 54%
• Female 47% 46%
Injured while playing sports in past year 10% 15%
Proportion with injuries involving teeth 52% (5.2% overall) 15% (2.25% overall) Proportion of injuries involving permanent 87% (4.52% overall) 63% (9.45% overall) incisors Dental treatment sought for permanent 100% tooth injuries 75% (reported overall) Dental treatment sought for primary tooth 50% injuries Visited dentist ≤2 hours after the injury 72% Not reported Cost of emergency dental treatment €214.23 Not reported (average)
27
According to O’Malley et al. (2012), 19% of parents did not know which type of
MG their children wore. The majority of parents reported that their children were wearing MFMG (64%), with only 4% wearing a CMG (“a mouthguard from the dentist”) and 12% wearing some other, undefined MG type (O’Malley et al.,
2012). Of note, O’Malley et al. (2012) published a selection of the questions from their questionnaire in their paper. The responses to the question on MG type were phrased as follows: “sports shop brand; dentist; other; don’t know”. They did not differentiate between SMG and MFMG in their questions, though the authors reported the proportion of the population wearing MFMG; therefore, the reliability of this data is questionable.
In 2012 the vast majority (78%) of children were not wearing MG for sports; the reasons parents gave for this included the cost of MG, a lack of knowledge about
MG and their benefits, and a lack of policies in schools and clubs for the use of
MG (O’Malley et al., 2012). By 2018, the proportion of children wearing MG for sports in an Irish cohort had increased to 68% (Evans and O’Malley, 2018). The majority of children were again wearing MFMG (64%), with 14% wearing “other”
MG types (Evans and O’Malley, 2018). Evans and O’Malley (2018) did not report which type of MG the remaining 20% of the sample were wearing. Only 2% of the study population were wearing CMG, yet 40% of parents surveyed reported that
CMG were the safer type of MG available (Evans and O’Malley, 2018).
These studies by O’Malley et al. (2012) and Evans and O’Malley (2018) are the only prior work examining the use of MG among sportspeople of any age in
Ireland. There were some significant limitations of these studies. The studies were school based, as opposed to being linked to sports organisations, which
28 may have influenced the results. Neither study did any further statistical analysis beyond descriptive statistics despite having relatively large sample sizes, so it was not possible to establish factors influencing MG wear or trauma experience from these studies. The studies did not survey the children themselves, nor did they examine the MG being worn. Therefore, the data must be interpreted with caution, as parents were a proxy for their children in both studies. Parent recall has been shown to be an imprecise measure of behaviour (Poulain et al., 2020) and past trauma experience (Cummings et al., 2005) in young children.
Nevertheless, despite these limitations, these studies give a valuable insight into patterns of MG use among primary school children in Ireland.
1.9 Mouthguard Types
Three types of MG are available: stock MG, mouth-formed (“boil-and-bite”) MG, and custom-made MG.
Stock MG (SMG) are available to buy over the counter in a variety of predetermined sizes and are the most inexpensive type of MG on the market
(Scott et al., 1994; Sigurdsson, 2013). It is not possible to customise these MG to fit the individual in any way; they tend to fit very loosely and therefore normally need to be kept in position by clenching to retain them in the mouth (Gawlak et al., 2014; Scott et al., 1994; Sigurdsson, 2013). This renders it difficult to speak or breathe properly while wearing SMG (Gawlak et al., 2014; Patrick et al., 2005;
Scott et al., 1994). Stock MG may also be easily dislodged from the teeth; they are considered to be the least protective of all MG types in spite of a lack of definitive scientific evidence to confirm this (Patrick et al., 2005; Sigurdsson,
2013). For this reason, SMG are generally not recommended.
29 Mouth-formed MG (MFMG) are also known as thermoformed or “boil-and-bite”
MG. These are fabricated from a thermoplastic material which allows them to be adapted to fit the individual by heating the MG in hot water and moulding it in the oral cavity through a combination of soft tissue pressures with the cheeks and tongue, and biting (Patrick et al., 2005; Sigurdsson, 2013). These are the most commonly used type of MG as they are relatively inexpensive, widely available, and more comfortable than SMG (O’Malley et al., 2012). Fit and retention of
MFMG tends to be better than SMG (Sigurdsson, 2013). Proper adaptation to the teeth and soft tissues can be challenging, however, as the temperatures needed to achieve a close fit are high so this may not be tolerated by the wearer, resulting in a poorly adapted MG (Guérard et al., 2017; Sigurdsson, 2013). It has been shown that coverage of the posterior teeth by MFMG is inadequate in 85% of adult players (Kuebker et al., 1986). Mouth-formed MG also tend to be relatively thin over occlusal and labial tooth surfaces (Patrick et al., 2005).
Custom-made MG (CMG) are made to fit the individual using dental impressions, models and either vacuum- or pressure-forming techniques
(American Academy of Pediatric Dentistry, 2016; Sigurdsson, 2013). They are generally believed to be the best-available MG, by being less bulky (Gawlak et al., 2014), more comfortable and more acceptable to sportspeople (Gawlak et al.,
2015; Greasley et al., 1998; Patrick et al., 2005; Scott et al., 1994). Custom MG have been shown to exhibit the best fit of all MG types (Scott et al., 1994), and are also associated with greater ability to speak and breathe during wear (Gawlak et al., 2016). There is little evidence to confirm that CMG provide greater protection against TDI – in vivo studies into this matter tend to have small sample sizes and poor study design (Sigurdsson, 2013).
30 1.10 Mouthguard Requirements
To be effective in reducing the risk of injury to the oral hard and soft tissues, a
MG must fit properly and be well-retained during play (Ferreira et al., 2019; Scott et al., 1994). The device should be comfortable to wear, with smooth rounded borders, and should be fabricated from a non-irritant material that is easily cleaned (Scott et al., 1994). It should effectively dissipate impact forces to minimize their effects on the teeth (Westerman et al., 2002c), while at the same time having no detrimental effect on the player’s ability to breathe (Collares et al.,
2014; Maeda et al., 2006).
The performance of a MG depends on its design and on the materials used in the fabrication process (Grewal et al., 2015). The thickness of a MG is proportional to its capacity to reduce stress and strain on the dentition, and hence reduce the likelihood of dental injury (Tribst et al., 2018). Criteria for the parameters of the ideal MG are outlined in Table 1.7.
Table 1.7 Criteria for ideal mouthguard fabrication.
Coverage Cover all maxillary teeth to the distal aspect of the second permanent molars (Scott et al., 1994) Thickness • Labial surface central incisors: 3–4 mm (Gialain et al., 2016; M. Maeda et al., 2008; Verissimo et al., 2016; Westerman et al., 2002a; Yamada et al., 2006) • Occlusal surface of posterior teeth: 2–3 mm (M. Maeda et al., 2008; Murakami et al., 2008) • Incisal edge of anterior teeth: 4 mm (Westerman et al., 2002a) • Palatal: 1mm (Scott et al., 1994) Labial 2mm short of vestibular reflection, rounded in cross section extension (McClelland et al., 1999) Palatal Just beyond the cervical margin of the palatal surface of the teeth, extension tapered in cross section (Karaganeva et al., 2019; Maeda et al., 2006)
Occlusion Balanced occlusion (McClelland et al., 1999; Takeda et al., 2008, 2004b; Veríssimo et al., 2017)
31
1.10.1 Thickness and Extension of Labial Flange of Mouthguards
The efficiency of a MG in absorbing and dissipating an impact force successfully to minimise injury to the dentoalveolar and soft tissues is related to the MG thickness in the area of impact (Barou et al., 2011). Much research has been undertaken to investigate the optimal MG thickness, taking into account the need for a balance between optimal impact absorption and comfort and wearability.
Scott et al. (1994) suggested a minimal thickness of 3mm labially to prevent injury to the maxillary anterior teeth. Since then, several in vitro investigations have been carried out regarding the optimal thickness of a MG. Westerman et al.
(2002a) found that increasing the labial thickness of a MG greater than 4mm did not provide any significant further benefit in terms of impact absorption; they reported that players were unlikely to tolerate such a bulky MG. Maeda et al.
(2008) also found that a thickness of 4mm labially would be optimal, but that wearing MG of such thickness may reduce player compliance and may prevent proper closure of the lips with the MG in situ. In more recent times, two studies using finite element analyses reported that the thickness of a MG should be 3-
4mm for optimal impact absorption and wearability (Gialain et al., 2016;
Verissimo et al., 2016). There are no clinical studies to confirm this as it would be unethical to put subjects at risk of dentoalveolar injury.
The labial MG flange should extend to within 2mm of the vestibular reflection and should be rounded in cross section, to cover the teeth and supporting tissues properly while also allowing for comfort and free movement of the soft tissues
(McClelland et al., 1999).
32 1.10.2 Thickness and Extension of Palatal Flange of Mouthguards
The palatal thickness of a MG is thought to be less relevant in terms of dentoalveolar protection, and more significant for comfort and wearability by influencing breathing, speaking and swallowing (Maeda et al., 2006). Players are less likely to wear a MG that they find uncomfortable. Scott et al. (1994) suggested that the palatal flange of the MG should be 1mm thick, with a tapered cross-section, and should extend to 10mm beyond the gingival margin. The tapered cross-section has been reported to be particularly important for minimizing the degree to which the MG impedes normal tongue position during wear (McClelland et al., 1999).
It has been reported that, if a MG has been made to fit correctly, a long palatal flange is less important for tooth protection and for MG retention (Gómez-Gimeno et al., 2019; Maeda et al., 2006; Yamada et al., 2006). Thus, its extension may be reduced to terminate at the cervical area of the teeth palatally without compromising protection, retention or fit, but maximising comfort for the player
(Gómez-Gimeno et al., 2019; Maeda et al., 2006; Yamada et al., 2006). Once the
MG properly engages the cervical undercut area, this has been found to be sufficient for MG retention (Maeda et al., 2009b).
1.10.3 Occlusal Thickness and Balanced Occlusion
Any MG should be thick enough occlusally to protect against vertical impact forces, without impinging on the normal freeway space of 2 – 3 mm in the mandibular rest position (M. Maeda et al., 2008; Murakami et al., 2008). Wearing
MG that are greater than 3mm thick occlusally at the posterior teeth can result in temporomandibular joint derangements (Murakami et al., 2008), as well as being uncomfortable and difficult for the player to tolerate (M. Maeda et al., 2008). A
33 thickness of 4mm incisally is necessary anteriorly as this is the high-risk area for trauma (Westerman et al., 2002a).
Balanced occlusion on the MG, especially anteriorly, has been shown in vitro to reduce the risk of dental injury and bony fractures (Takeda et al., 2004a). This is because anterior occlusion helps to improve impact absorption and force dissipation compared to scenarios where there is either no MG or one with insufficient anterior occlusion (Takeda et al., 2008). The lower anterior teeth are important for supporting the MG in impact absorption (Takeda et al., 2008). In practical terms, to achieve balanced occlusion on a MG, maxillary and mandibular impressions along with an accurate interocclusal record must be supplied to the dental laboratory; alternatively, the use of digital scanning techniques may facilitate balanced occlusion (Li et al., 2020).
A non-linear finite element analysis examining the influence of antagonist tooth contact on the MG with regard to protection against dental injury found that there was a reduction in internal stresses and strains in dental hard tissues in response to an external force in the presence of a MG, with or without anterior tooth contact
(Veríssimo et al., 2017). However, anterior tooth contact on MG seemed to reduce the likelihood of MG displacement due to impact forces, thus preventing injury to the teeth (Veríssimo et al., 2017).
1.11 The Influence of Mouthguards on Normal Physiological
Functions and Sports Performance
There has been much investigation into the impact of MG on athletic performance and normal physiological functions (breathing, swallowing, speech). Difficulties
34 with breathing and speech while wearing MG are mostly self-reported by players
(Duarte-Pereira et al., 2008; Duddy et al., 2012; Gawlak et al., 2016).
In terms of athletic performance, it has been proposed that wearing and clenching on a MG may increase total-body strength through generalised activation of muscles throughout the body (Busca et al., 2016). Again, evidence is conflicting and there is significant heterogeneity among studies. A small study by Busca et al. (2016) investigated the effect of a CMG fabricated in a protrusive position of the mandible and found a significant increase in upper body strength compared to no MG. Hanson et al. (2018) found no significant difference in athletic performance between a normal MFMG and a vented MFMG. It is difficult to draw a conclusion based on this available evidence.
The influence of MG on cardiorespiratory parameters such as maximal oxygen uptake (VO2 max), minute ventilation (VE) and heart rate (HR) have been extensively investigated. While the level of evidence is generally low (Ferreira et al., 2019), overall, it appears that wearing a MG has no significant measurable negative effects on cardiorespiratory parameters (Collares et al., 2014; Duarte-
Pereira et al., 2008; Gebauer et al., 2011; Green et al., 2018).
There is conflicting evidence as to whether the type of MG worn has any bearing on outcomes. There appears to be a trend for CMG being less detrimental to normal physiological functions during exercise than MFMG (Duarte-Pereira et al.,
2008; Duddy et al., 2012). Vented MFMG have been developed in an effort to overcome breathing issues; however, there has been no evidence of a significant respiratory improvement by wearing these in comparison to regular MFMG
(Bailey et al., 2015; Hanson et al., 2018).
35 1.11.1 Psychosocial Effects of Mouthguard Use in Sports
Authors have suggested that the use of a MG may be associated with a heightened perception of security and protection, leading players to take greater risks in contact sports (McGuine et al., 2014; Patrick et al., 2005). Patrick et al.
(2005) noted that this may be especially dangerous where an ill-fitting MG is worn, conferring a false sense of security on players, potentially increasing their overall risk of injury.
A cross-sectional study of a cohort of high school football players in Wisconsin,
USA investigated the risk of sports-related concussion relating to the protective equipment worn (helmet, MG) and player characteristics such as age, competition level, and previous history of concussion (McGuine et al., 2014). It was reported that players who wore a CMG had a 60% greater chance of suffering a concussion compared to those who wore a MFMG (McGuine et al.,
2014). The authors suggested that this may have been because players wearing a CMG felt that this MG afforded them greater protection against injuries, therefore they may have played "with less regard or fear of sustaining injury"
(McGuine et al., 2014). However, players were not asked about their level of risk- taking, and the proportion of participants wearing CMG was only 8.7% of the overall study population, so this finding may not be representative of all players wearing CMG (McGuine et al., 2014).
36 1.12 Requirements for Mouthguard Materials
1.12.1 Protective Qualities
Shock absorption, hardness and stiffness of a material confer its protective properties. Shock absorption refers to the MG material’s ability to reduce the transmission of impact energy to underlying dentoalveolar structures (Knapik et al., 2007; M. Maeda et al., 2008). This can be experimentally measured either by assessing the degree of rebound of the material following an impact, or by direct measurement of force on a transducer under the material (Knapik et al., 2007). If a MG material has high shock absorption values, this means it will transfer lower forces to the underlying structures and therefore be more protective for the teeth and surrounding structures (Knapik et al., 2007).
Hardness is “the resistance of a material to penetration with a load applied”
(Knapik et al., 2007). The hardness of MG materials is usually measured using the Shore A scale. A device with an indenter which applies a specific load to the material is used to assess the hardness. If the indenter penetrates the material completely, the “A” value is 0, and if there is no penetration the “A” value is 100
(Knapik et al., 2007).
Stiffness refers to the material’s ability to withstand deflection by an impact force and is measured by Young’s modulus (N/m2); it relates to the material’s hardness.
With increasing hardness, the material becomes stiffer (Knapik et al., 2007). Most
MG materials are elastic in nature; therefore, deformation will be proportional to load (Knapik et al., 2007). The material will revert to its original configuration once the applied force is removed. If stiffness values are low, the material will deform more under applied force, resulting in greater force transmission to underlying
37 structures (Knapik et al., 2007). Greater stiffness values mean less deformation of the material and hence allow for force distribution over a wider area (Knapik et al., 2007).
From the above definitions, it would appear that for a MG to be sufficiently protective, the material used in MG fabrication must be able to sufficiently absorb an impact force and reduce the forces transmitted to the underlying tissues.
Additionally, moderate levels of both hardness and stiffness are required to strike a balance between permanent deformation and force distribution over a larger area.
1.12.1.1 Durability
Durability of a MG material relates to its tear strength and tensile strength (Knapik et al., 2007). Tear strength is a material’s ability to resist tearing forces, and is measured in N/cm (Knapik et al., 2007). Tensile strength is the ability to withstand a pulling force (N/cm2) (Knapik et al., 2007). A MG needs appropriate tear and tensile strength to resist biting and chewing forces of its user (Knapik et al., 2007).
1.12.1.2 Stability in the Oral Environment
Water absorption is the amount of water (or saliva, in the case of a MG) taken up by a material over time (Knapik et al., 2007). Low water absorbency is preferable for MG stability to reduce the retention of saliva and oral bacteria within the MG
(Knapik et al., 2007). It can be measured by the amount of water absorbed per cm2, or as a percentage of the original weight, after being in water for a given time or temperature (Knapik et al., 2007).
38 1.13 Materials used in the Fabrication of Mouthguards
A variety of materials have been used to fabricate MG. These include ethylene vinyl acetate, polyolefin, acrylic resin, latex rubber, polyurethane, polyvinylchloride and silicon rubber (Green, 2017; Suzuki et al., 2007).
Currently, the most popular material for MG is ethylene vinyl acetate (EVA)
(Westerman et al., 2002a). It is widely available, affordable, and easily manipulated (Maeda et al., 2009a). It is available as either square or round blanks
(Takahashi et al., 2014a) in a variety of colours (Gould et al., 2009a). The physical properties of EVA can be altered by changing the ratio of ethylene to vinyl acetate
(Green, 2017; Westerman et al., 2002a). It has been found that a proportion of
18% vinyl acetate provides optimal shock absorption (Bishop et al., 1985). This increases MG flexibility, toughness, softness, shock absorption and water absorbency, all of which are favourable properties (Park et al., 1994). However,
18% vinyl acetate is associated with a reduction in tear strength and hardness; this is considered acceptable given the overall balance of positive characteristics
(Green, 2017).
1.14 Materials Science: Stock and Mouth-formed Mouthguards
Stock MG are fabricated from either EVA or polyurethane (Patrick et al., 2005).
Formerly, polyvinylchloride was used to make these MG; however, this is no longer permitted under EU legislation (Patrick et al., 2005).
Mouth-formed MG (MFMG) are normally fabricated from EVA. To achieve an appropriate fit, the core temperature of the MFMG must exceed the melting point of the material used when placed intraorally to enable optimal adaptation to the teeth and soft tissues, yet the surface temperature must be low enough to avoid
39 soft tissue burns (Guérard et al., 2014). Equally, the biting time must be long enough to allow the material to reach its crystallisation temperature and harden, thus ensuring that the form of the dentition has been appropriately replicated in the MFMG (Guérard et al., 2014).
These conditions are difficult to achieve. Normally, MFMG are heated in boiling water to soften them, before being cooled to a temperature at which they may be sufficiently tolerated in the oral cavity to be moulded without causing soft tissue burns, normally at around 60°C (Grewal et al., 2015; Guérard et al., 2014). This means that, by the time the MFMG is fitted intraorally, the core temperature has fallen beneath the melting temperature, and the crystallisation temperature of
EVA is reached, resulting in a poor MFMG fit (Guérard et al., 2017, 2014;
Hoffmann et al., 1999; Patrick et al., 2005).
The melting temperature of EVA is influenced by the percentage of vinyl acetate in the EVA polymer; this varies between MFMGs, which in turn creates variable thermal properties (Guérard et al., 2014). It is unclear as to whether the manufacturers of MFMG allow for the specific thermal properties of each material when providing guidance in relation to characteristic times and temperatures
(Guérard et al., 2014).
1.15 Materials Science: Custom Mouthguards
Custom MG (CMG) are made by heating an EVA sheet and shaping it to the working model using either pressure or vacuum moulding in a process called thermoforming (Maeda et al., 2009a). Accuracy of MG fit and the final thickness are affected by several variables within this process (Table 1.8), including the fabrication technique chosen, working model characteristics and position, and
40 conditions relating to the EVA sheet itself (Maeda et al., 2009a). Evidence to date comes from laboratory studies; there is a lack of clinical evidence in this area for ethical reasons.
1.15.1 Custom Mouthguard Fabrication Techniques
Thermoforming machines consist of a base with a platform on which the working model is positioned, a heating element at the top of a post attached to the base, and a sheet frame to hold the EVA sheet (Takahashi and Araie, 2017). The sheet frame is heated above the model and, once it has reached the appropriate temperature, the frame is pulled down over the model to fabricate the MG
(Takahashi and Araie, 2017).
41 Table 1.8 Variables affecting MG fabrication
Vacuum-forming Fabrication technique Pressure-forming Moisture content Working model Temperature characteristics Position within thermoforming machine Angulation and incisor-molar height Stretching and thinning when heated Core temperature of sheet Temperature discrepancy between surfaces Characteristics inherent Distance from heater to EVA material Sagging distance from baseline position in sheet frame holder Colour Shape Holding pattern Notches/grooves within sheet Lamination of multiple sheets Adaptations/modifications Inclusions within EVA sheet: • Hard material • Air cells • Foam cells
1.15.2 Machine Characteristics: Vacuum Forming
Application of a vacuum force creates a negative pressure between the working model and the internal surface of the heated EVA sheet for approximately 10 seconds, allowing EVA adaptation around the working model (Mizuhashi et al.,
2016b; Takahashi and Bando, 2019a). Vacuum-forming machines are most commonly used for MG formation because they are relatively affordable and easy to use (Mizuhashi et al., 2016b; Yonehata et al., 2003). They generally have
42 quadrangular sheet holders, but may be fitted with circular sheet holders
(Takahashi et al., 2014a, 2014b). It is unclear as to whether it is better for final
MG fit and thickness to apply the vacuum before or after pulling the material down on to the model, with directly opposing views in the literature (Mizuhashi et al.,
2016c, 2013).
1.15.3 Machine Characteristics: Pressure Forming
Pressure-forming involves application of pressure on the external surface of the heated EVA sheet, pressing it against the model typically for several minutes
(Takahashi and Bando, 2019a). This technique is less-commonly used, being more technique-sensitive and costly (Mizuhashi et al., 2016b). Pressure-formers have circular sheet holders (Takahashi et al., 2014b).
1.15.4 Vacuum Forming vs. Pressure Forming: The Evidence
There is some evidence that pressure-formed MG display improved EVA adaptation and therefore better MG fit, retention and dimensional stability when compared to vacuum-formed MG (Mizuhashi and Koide, 2017a; Waked et al.,
2002). The difference in final MG thickness between the two techniques is less clear, with conflicting reports in the literature (Mizuhashi et al., 2016b; Mizuhashi and Koide, 2017a). A combined technique has been developed, whereby the vacuum is applied first followed by pressure application. There is some evidence that thicker MG are formed by this technique in comparison to vacuum or pressure formation alone; however, the level of evidence is low (Mizuhashi et al.,
2015a).
The results from these laboratory studies have not been verified in vivo; therefore, though statistical differences have been reported, it is not known whether there
43 would be a clinically observable difference in MG fit and retention between techniques.
1.15.5 Working Model Characteristics
The evidence in the literature relating to the working model’s effect on the final
MG is all based on research based on cast models poured from impressions made of the player’s teeth. Newer techniques of working model fabrication involving digital intraoral scanners and 3D printers are emerging; it is unclear what influence, if any, these new conditions may have on the fabrication of CMG.
1.15.5.1 Dry Working Model
Residual moisture in the working cast prevents the escape of air trapped between the EVA sheet and the model, creating air pockets which limits adaptation of the
EVA sheet to the working model (Yonehata et al., 2003). There is a greater accuracy of MG fit when fabricated on a dry working model compared to a wet one (Maeda et al., 2009b; Yonehata et al., 2003).
1.15.5.2 Heated Working Model
Heating the working model reduces the temperature differential between the heated and non-heated surface of the EVA sheet. This allows a more uniform heat distribution within the sheet, resulting in closer adaptation to the model during thermoforming & improved final MG fit (Yonehata et al., 2003).
1.15.5.3 Position Within Forming Machine
The closer the incisal edge (of the central incisors) of the working model is to the anterior edge of the sheet holder, the thinner the labial surface of the MG will be because the EVA sheet must stretch further to cover the anterior surface of the model (Takahashi et al., 2017). For pressure forming, it has been reported that
44 the incisal edge of the model should be placed in the centre of the former, as the
EVA sheet is thickest in the centre when heated (Mizuhashi et al., 2016a).
Position within the forming machine appears to be more important for pressure- formed MG than for vacuum-formed MG (Takahashi et al., 2017).
Labial MG thickness may be improved if the model is centred in the machine and the EVA sheet is heated as normal, before being lowered to contact the model; the model is then pushed forward by 20mm and the vacuum or pressure is then applied (Takahashi and Bando, 2019a, 2019b). This reduces the stretching and thinning on the anterior portion of the EVA sheet during forming (Takahashi and
Bando, 2019a, 2019b).
1.15.5.4 Working Model Angle
An acute (<90°) angle between the labial surface of the central incisors and the base of the model improves final MG thickness (Farrington et al., 2016; Mizuhashi et al., 2017; Takahashi et al., 2014c). This can be achieved by trimming the model so that the incisor height is greater than the molar height, thus ensuring there is no undercut at the incisors (Takahashi et al., 2014c). Excessively increasing incisal height may reduce labial MG thickness by increasing the distance over which the softened EVA sheet would have to stretch (Del Rossi and Leyte-Vidal,
2007). An incisor height of 20mm and molar height of 15mm is most appropriate for uniform overall MG thickness (Del Rossi and Leyte-Vidal, 2007; Takahashi et al., 2014c).
45 1.15.6 Characteristics of EVA blanks
1.15.6.1 Release of Internal Distortions
Ethylene vinyl acetate is fabricated by extrusion moulding. A consequence of this technique is the generation of internal distortions within the final EVA product, resulting in unpredictable heating patterns and overall thermal shrinkage of approximately 5% over the entire sheet when heated (Takahashi et al., 2016a,
2013). For the final MG, this produces a loss of thickness, especially when stretching during formation is taken into account (Del Rossi and Leyte-Vidal,
2007; Geary and Kinirons, 2008; Takahashi et al., 2016a; Tunc et al., 2013). Del
Rossi and Leyte-Vidal (2007) reported an average EVA thinning rate of 46% at the occlusal surface of the molars, and of 47-60% at the labial/buccal surface of the canines and first molars respectively. Thinning rates of 52%-72% were reported by Geary and Kinirons (2008), with greater degrees of thinning occurring at incisal edges and cusp tips compared to elsewhere (Geary and Kinirons,
2008). Similarly, Tunc et al. (2013) reported incisal edge thinning of 53-59% at the central incisors, and labial thinning of 42-46% at the same teeth post- thermoforming.
1.15.6.2 Thinning During Adaptation to Working Model
Further thinning of EVA occurs during adaptation of the MG material on the cast
(Takahashi et al., 2013). This is due to pressures exerted during either vacuum- or pressure-forming, and to the inherent anatomical form of the dentition. The heated EVA sheet contacts the relatively sharp incisal edges and cusp tips first, and stretches downwards and outwards to cover the remainder of the model (Del
Rossi and Leyte-Vidal, 2007). This stretching is believed to be partially responsible for consistent reduction in incisal and cuspal MG thickness compared
46 to that at the cervical margin of MG, regardless of forming method (Mizuhashi et al., 2013).
1.15.6.3 Sagging Distance and Heating Temperature
Heated EVA sheets sag under their own weight, so the central portion is thicker and the stretched peripheral portion is thinner (Mizuhashi et al., 2016a;
Takahashi et al., 2016a). The optimal sagging distance that a heated EVA sheet should reach before either pressure- or vacuum-forming a MG is 15mm below the level of the sheet holder, to maximise final MG thickness (Takahashi et al.,
2016b). The optimal heating temperature for EVA has been reported to be 120°C to maintain final MG thickness, for both vacuum- and pressure-forming
(Mizuhashi et al., 2018; Mizuhashi and Koide, 2017b).
1.15.6.4 Differential Heating of EVA Sheet
During heat softening of the EVA, the top of the sheet is heated more than the bottom of the sheet due to its closer proximity to the heat source (Takahashi and
Araie, 2017). This creates a temperature discrepancy and uneven softening of the sheet, with greater thinning occurring especially over incisal edges and occlusal cusp tips (Takahashi and Araie, 2017). Several techniques have been suggested to mitigate this effect.
Partially heating the EVA sheet, before rotating the frame and heating the other side reportedly improves MG fit, but no significant improvement in thickness has been achieved with this technique (Mizuhashi et al., 2014a). Lowering the frame away from the heat source to allow even, slow heating of the EVA sheet has also been advocated (Takahashi et al., 2015; Takahashi and Koide, 2016). This has improved final MG thickness without a compromise in MG fit (Takahashi and
47 Koide, 2016). Switching off the heat source once the sheet has sagged 10mm from the neutral level and allowing it to sag to 15mm before moulding it to the cast has been successful in reducing the rate of EVA thinning (Takahashi et al.,
2015). Nevertheless, the temperature differential still renders it difficult to achieve a satisfactory MG fit unless the core temperature of the EVA has reached its melting temperature (Guérard et al., 2017).
1.15.6.5 Colour of EVA Material
The colour of the EVA blank may affect overall the properties of the final MG.
Light or transparent materials reflect energy, while darker materials absorb energy. Therefore, it is postulated that darker materials may achieve higher temperatures through greater absorption of infrared energy during thermoforming, and hence result in an improved MG fit compared to lighter or transparent materials (Del Rossi et al., 2008). It is unclear, however, what the influence of colour on MG thickness is; while there may be colour-dependent differences in MG thickness, it may be influenced by the type of pigment incorporated into the material, and therefore may not be as simple as differentiating between light and dark colours (Takahashi et al., 2012).
1.15.7 Modifications to Optimise Thickness and Retention of EVA Custom
Mouthguards
Mouthguards made from single sheets of EVA tend to be less than 3.0mm thick
(Mizuhashi and Koide, 2017a). It has been calculated that, to achieve a final MG thickness of 3.0mm, a single EVA blank thickness of 5.6mm would be needed to account for the average reduction in thickness after thermoforming (Mizuhashi et al., 2014b). Square EVA blanks appear to result in thicker MG post-fabrication than circular sheets (Takahashi et al., 2014a). Using circular sheet frames may
48 improve MG fit and retention, especially when used to secure square EVA sheets
(Takahashi et al., 2014a).
Laminating two EVA layers together by either vacuum- or pressure-forming creates a MG which is closer to the ideal thickness (de Wet et al., 1999; Geary and Kinirons, 2008; Mizuhashi et al., 2016b; Mizuhashi and Koide, 2020; Tunc et al., 2013). The initial layer is formed over the working model as normal, before the second sheet is formed over the first layer (Mizuhashi et al., 2016b; Mizuhashi and Koide, 2020). Mizuhashi and Koide (2020) reported that the final labial thickness at the central incisors was greater for pressure-formed MG when the initial layer (3mm) was thicker than the second layer (2mm). However, while lamination may improve final MG thickness, there is still an overall loss of thickness of approximately 30%, similar to that for single-layer MG (Tunc et al.,
2013).
Fabricating a single-layer EVA MG with optimal dimensions and protective ability would be ideal in terms of time and cost. Modifications to the EVA sheet itself through the use of grooves or notches, especially anteriorly, to relieve the strain associated with stretching during thermoforming have been tested with some success in maintaining thickness of EVA post-thermoforming (Mizuhashi et al.,
2015b; Mizuhashi and Koide, 2019, 2018; Takahashi et al., 2014c, 2013).
However, these techniques are technique-sensitive and time consuming and are not commonly used; fabrication of laminated MG is more predictable.
49 1.15.8 Modifications to Optimise Shock Absorption Performance of EVA
Custom Mouthguards
Modifications to EVA to enhance the protective ability of the material itself have been investigated. Such inherent modifications would improve protection while minimizing MG thickness, thereby improving wearer comfort (Westerman et al.,
2002b). Including air cells within the EVA material has been shown to reduce impact forces transmitted to the teeth by up to 32% (Westerman et al., 2002b,
1997). The same research group investigated including foam cells within the EVA material, but found no significant improvement in protective ability (Westerman et al., 2002c).
Fabricating laminated MG with a layer of a harder material between the EVA layers has been examined by several authors. It has been reported that a hard insert performs better than a softer silicone insert in laboratory impact tests
(Bemelmanns and Pfeiffer, 2001). Takeda et al. (2006) compared the performance of a conventional laminated EVA MG with that of a MG constructed from two layers of EVA with a hard acrylic layer in between. Including the hard acrylic layer significantly improved shock absorption and reduced tooth deflection
(Takeda et al., 2006). The protective effect was even greater for MG fabricated with the hard insertion and a space between the MG and the anterior teeth
(Takeda et al., 2006). The authors theorised that the space may have allowed some bending of the MG in response to applied force, dissipating energy before the impact force reached the teeth (Takeda et al., 2006).
Other novel techniques investigated to improve EVA shock absorption include using metal reinforcers within the MG material, such as an orthodontic arch wire or a titanium strip (Kataoka et al., 2014), inserting a sponge layer (de Wet et al.,
50 1999), and inserting a layer of a visco-elastic polyurethane called Sorbothane
(Bulsara and Matthew, 1998) among the layers of EVA in a laminated MG. These have had variable results and are not used in practice.
1.16 Mouthguard Deformation Over Time
Dimensional stability of an EVA MG is desirable to provide protection to the wearer, while at the same time remaining comfortable to wear (Waked et al.,
2002). With continued wear over time, the average MG is subjected to repeated episodes of heating in intraoral temperatures and cooling at room temperature, as well as repeated wet-dry cycles between being bathed in saliva during wear, to being stored often in dry environments (Gould et al., 2009a, 2009b; Waked et al., 2002). It has also been observed that players may engage in inappropriate chewing on their MG as a habit (Del Rossi et al., 2007).
These aging-related conditions cause notable changes in MG thickness and fit over time, mostly in the anterior part of the MG (Del Rossi et al., 2007; Waked et al., 2002). A study investigating dimensional change in laminated CMG provided to 15 high school football players found significant reductions in labial and occlusal MG thickness over the course of a 12-week sports season (Del Rossi et al., 2007). An older study by Chaconas et al. (1985) compared dimensional stability of clear EVA, laminate EVA and polyurethane CMG. At the labial incisor surface, clear materials demonstrated the greatest dimensional change and laminated demonstrated the least; therefore, laminated materials were the most stable over time (Chaconas et al., 1985).
Repeated heating and cooling of EVA may alter the mechanical properties of the material, increasing the likelihood of deformation by approaching its melting
51 temperature at intraoral temperatures (Gould et al., 2009a, 2009b). Pressure- laminated MG appear to be associated with the least dimensional change over time (Waked et al., 2002); therefore, this technique may be preferable for MG fabrication.
The literature search did not reveal any studies reporting on dimensional stability of MFMG. Nevertheless, regardless of MG type, all players must be educated in care for their MG in terms of avoidance of chewing habits, MG hygiene, and appropriate storage to reduce the likelihood of iatrogenic MG damage and prolong the life span of their appliance (Del Rossi et al., 2007).
1.17 Mouthguards: Microbiological and Hygiene Considerations
Mouthguards are a foreign surface in the oral cavity on which micro-organisms can establish colonies. If MG surface is rough, this can increase the potential for microbial attachment, increasing the microbial load intraorally which may lead to increased risk of periodontal disease and dental caries (Almeida et al., 2018).
It has been found that non-polished EVA is the smoothest possible surface with the least potential for microbial colonization (Almeida et al., 2018). Some polishing of CMG borders is always needed, however, after the MG has been cut from the EVA sheet after thermoforming (Almeida et al., 2018). This polishing should be carried out by rotary instruments in conjunction with a hot-air burner, as this technique has been found to be associated with lower surface roughness
(Almeida et al., 2018).
There has been little investigation into level of knowledge around MG hygiene. A small questionnaire-based study of 22 athletes found that only 2 players (9%) of the sample had received advice in relation to cleaning their MG, and less than
52 half were always or sometimes cleaning their MG (Namba et al., 2013). Glass et al. (2011) examined microbial colonization in MG worn by football players over one season and found that MG which were not disinfected were heavily contaminated after use over time. Salivary streptococci have been found to survive on moist surfaces if kept in non-ventilated conditions (Ogawa et al.,
2012). An in vitro study found that Enterococcus faecalis, normal salivary bacteria and Candida albicans also grow well on EVA (D’Ercole et al., 2020). There is, therefore, a significant need for clear protocols in relation to MG cleaning and storage to be formulated, and for players, parents and coaches to be educated appropriately.
It has been found to be difficult, if not impossible, to completely eliminate microbial colonization from MG (D’Ercole et al., 2020). Water is ineffective in killing bacteria, but may help to reduce bacterial load by reducing the strength of initial microbial colonization on the MG surface (D’Ercole et al., 2020; Ogawa et al., 2012). Using fluoride toothpaste is abrasive and leaves behind small particles to which microbes can attach (D’Ercole et al., 2020). Hydrogen peroxide (H2O2) and 5% sodium hypochlorite (NaOCl) have both been found to significantly reduce microbial load on EVA surfaces in an in vitro study; however, NaOCl may increase the surface roughness of the material and should be used with caution
(D’Ercole et al., 2020). Mouthguards should also be stored in ventilated conditions such as a perforated box, and away from direct sunlight or other heat sources which may result in deformation of the MG material (D’Ercole et al.,
2020).
Mouthguards have been found to be associated with oral lesions, such as ulcerations and frictional keratosis (Glass et al., 2009). This is particularly the
53 case when MG are distorted or develop sharp edges due to wear and tear over the course of wearing MG for a season of sports, and it is possible that this may lead to non-compliance with MG. Glass et al. (2009) found that the prevalence of soft tissue lesions among 62 players wearing MG for a season of sports increased from 75.8% at the beginning of the season to 96% at the end of the season.
Therefore, players should be advised to replace their MG when it becomes distorted, if any sharp edges develop, and if there are any ulcerations or other lesions in the mouth which develop in association with MG wear (Glass et al.,
2009).
1.18 Orthodontic Patients, Children in the Mixed Dentition, and
Mouthguards
Patients wearing fixed orthodontic appliances are at greater risk of TDI; teeth undergoing orthodontic movement are more mobile, and the presence of appliances is a risk for soft tissue injuries (Newsome et al., 2001). Orthodontic treatment also tends to be carried out in late childhood and early adolescence; this is a period during which there is a greater risk of trauma overall, with the majority of dental injuries occurring before age 20 (Andersson et al., 2019). It has been reported that many orthodontic patients do not routinely wear MG for sporting activities (Croll and Castaldi, 1996).
Orthodontic appliances present a unique set of challenges for the fabrication of a
MG. Brackets fixed to the teeth along with their accompanying arch wires need to be accommodated within the MG, without the MG material being too closely adapted to them, as this would increase the risk of brackets debonding during placement and removal of the MG (Salam and Caldwell, 2008). The position of
54 teeth can change rapidly once fixed appliances are fitted; this change in configuration must also be allowed for (Salam and Caldwell, 2008). This means
CMG fabricated without accommodating these scenarios may not fit properly soon after fabrication, and require frequent replacement, which would quickly become very costly.
Children in the mixed dentition phase of dental development also require additional considerations due to the exfoliation and gradual eruption of primary and permanent teeth respectively (Croll and Castaldi, 2004). Custom MG fabricated without allowing for changes in the dentition of a growing child would require regular replacement – a significant financial burden on parents (Croll and
Castaldi, 2004). For this reason, children in the mixed dentition may be more likely to be wearing MFMG. Survey-based studies have reported that children mostly wear these MG (Evans and O’Malley, 2018; Kroon et al., 2016; O’Malley et al., 2012), though the reasons for choosing these MG have not been reported.
Developing ways to modify CMG to accommodate future changes in the dentition would allow these devices to be useful and usable for a longer period of time for children in the mixed dentition and for those in fixed orthodontic treatment (Croll and Castaldi, 2004). Several authors have proposed fabrication methods to overcome the issues presented by orthodontic appliances.
Croll and Castaldi (2004) recommend placing wax on orthodontic brackets to block them out, before taking an alginate impression and pouring a stone model of the patient’s dentition. Areas on the model with brackets and wires, as well as areas of projected tooth movement, are then blocked out on the model, and an
EVA MG fabricated on the resulting model as normal (Croll and Castaldi, 2004).
55 A similar proposed method involves taking alginate impression and pouring a stone model, before applying a cut catheter tube to the brackets and arch wires on the teeth (Y. Maeda et al., 2008). An EVA MG may be formed over the model with the tube in place; once fabricated, the tube can be removed from the fitting surface of the MG as it does not fuse to EVA, providing space for the arch wire
(Y. Maeda et al., 2008). This method would require ongoing review and adjustment of the MG to accommodate new tooth positions as orthodontic treatment progresses (Y. Maeda et al., 2008). It must be noted that there is no evidence on the performance of these adapted MG in terms of protective ability and prevention of dentoalveolar trauma.
There are several types of mouth-formed and stock MG available on the market targeted specifically at orthodontic patients (“Shock Doctor Braces”, Shock
Doctor, Inc., 3650 Annapolis Lane, Suite 115, Plymouth, MN, USA; “Masel
Double Mouthguard”, Masel, 2701 Bartram Road, Bristol, PA, USA). They are likely less retentive and may need to be frequently replaced (Meade, 2018).
There is little evidence to determine their suitability in terms of dentoalveolar protection in this population (Meade, 2018; Salam and Caldwell, 2008).
A survey of orthodontic consultants working in the NHS orthodontic service revealed variations in recommendations for MG use (Bussell and Barreto, 2014).
Almost three-quarters of those surveyed routinely advise use of MG during contact sports; however, only 9% recommend MG use for all contact sports
(Bussell and Barreto, 2014). The vast majority recommended MG use for rugby
(94%), boxing (91%), and hockey (90%); MFMG were recommended by 61% of the sample (Bussell and Barreto, 2014). Mouth-formed MG were also
56 recommended by the majority of orthodontists in a more recent study, yet the majority of their patients reported wearing a SMG (Bastian et al., 2020).
There is no clear evidence for which type of MG is best for orthodontic patients or for children in the mixed dentition (Salam and Caldwell, 2008). Guidance from the British Orthodontic Society (2019) states that a MG should be used to reduce risk of dental trauma, and that a CMG will provide the best dentoalveolar protection. However, it is stated that “all of the three types of mouthguard may be used” (British Orthodontic Society, 2019). An individualised approach is likely to be best, therefore, taking into account the child’s level of sports participation and their likely compliance, as well as their family circumstances in terms of affordability of MG requiring more frequent replacement (Salam and Caldwell,
2008). A modified CMG is believed to be the ideal appliance in these situations.
1.19 Which Mouthguard is best? – The Evidence
“The most effective MG is one that limits the force transmitted to the maxillary dental arch” (Guérard et al., 2017).
The above quote defines what is meant by the “best” MG. Limiting force transmission may be achieved through optimal thickness, shock absorption, and retention.
Fit and retention are important parameters in considering whether a MG is suitable or not. Guérard et al. (2017) concluded that a poorly-fitting MFMG can result in excessive space between the MG and the teeth. This can increase the likelihood of MFMG displacement under impact force (McCrory et al., 2013), as well as making the MFMG less comfortable to wear (Guérard et al., 2017). Poor
57 MFMG fit also leads to complaints of nausea, looseness and discomfort from players (DeYoung et al., 1994).
It has been reported that a reduction of occlusal thickness of 70%-99% occurs during MFMG fabrication due to excessive uncontrolled biting forces (Park et al.,
1994). Additionally, occlusal coverage of MFMG was found to be inadequate in
85% of college basketball players, possibly due to difficulties in proper self- positioning of MG during moulding (Kuebker et al., 1986). Insufficient occlusal protection in MFMG is reportedly associated with an increased risk of mandibular fracture (Takeda et al., 2004a). Labial thicknesses less than the recommended
3mm have also been reported post-thermoforming in MFMG (Guérard et al.,
2017).
In impact tests, it has been shown that MFMG are less protective than CMG in terms of shock absorptive ability (Bemelmanns and Pfeiffer, 2001). Greasley et al. (1998) compared MFMG and CMG performance in an in vitro impact study.
An average of 6 teeth were fractured when there was no MG, 4.5 teeth fractured with MFMG and only 0.5 teeth fractured with CMG, leading the authors to recommend against the use of MFMG in favour of CMG (Greasley et al., 1998).
There is a wealth of evidence from in vitro studies as to why and how CMG are better than MFMG for prevention and protection against dental injury, though evidence from clinical studies is lacking. There is improved occlusal stability and fit with CMG (Gawlak et al., 2015; Hoffmann et al., 1999; Patrick et al., 2005).
Custom MG are associated with lower rates of thinning during fabrication (25-
50%) compared to over 70% for MFMG (Park et al., 1994). Energy absorption of
58 CMG is significantly better than MFMG which translates to fewer dentoalveolar fractures, especially in the case of laminated MG (Greasley et al., 1998).
There is limited evidence that MFMG fabricated from polyolefin as opposed to
EVA may provide sufficient dentoalveolar protection if adapted to the dentition by a dentist, as polyolefin has a wider working temperature than EVA (80-230ºC for polyolefin vs 80-120°C for EVA) thus increasing the working time (Grewal et al.,
2015). This was only a small study, however, so further investigation into this is warranted.
On balance, considering the currently available evidence, a well-fabricated laminated custom EVA MG of sufficient extension, retention and thickness with balanced occlusion will offer improved protection and comfort than MFMG. Stock
MG should not be recommended as it can be expected that they will fail to provide appropriate protection for the dentition.
1.20 Concluding Remarks
There is a wealth of evidence regarding the desirable characteristics of a MG from materials science in vitro research, mostly relating to CMG, with a scarcity of evidence relating to MFMG. There is very little information relating to compliance of children playing sports with MG rules, MG preferences, and the characteristics (retention, extension, thickness) of the existing MG being worn by these children. A lack of evidence with regard to parent MG knowledge has also been identified, particularly in relation to care of MG. This highlights the need for further investigation in this arena.
59 1.21 Introduction to current research study
A policy of mandatory MG use has been in place for 6 years in the GAA for Gaelic football players at all levels. This study sought to investigate compliance rates with the GAA’s requirement for MG to be worn while participating in Gaelic football, both during training sessions and matches, in a sample of 9-16-year-old boys and girls in a number of clubs based around Dublin city.
In addition to measuring compliance, this study sought to establish the types of
MG being worn, and whether the MGs being worn could be considered protective of the dentition of the wearer (fit for their intended purpose).
The study also sought to investigate and compare the knowledge, attitudes and behaviours of the children and their parents in relation to the use of MG in sports.
1.21.1 Aims
1. To investigate whether a sample of children playing Gaelic football are
wearing MG for both training sessions and matches, as mandated by the
Gaelic Athletic Association (GAA);
2. To establish whether the MG worn meet recommendations for adequate
dentoalveolar protection, as outlined in materials science literature;
3. To ascertain parent and child knowledge on MG types, and care and use
of MG.
1.21.2 Objectives
1. To examine a sample of children (boys and girls) who play Gaelic
football and assess their MG for fit, retention, coverage and thickness;
60 2. To survey children and parents using separate questionnaires to
establish their knowledge and opinions with regard to the wearing of MG
for sports.
1.21.3 Hypotheses
1. MG are routinely worn by children playing Gaelic football for training
sessions and matches.
2. Numerous MG types are being worn; the majority of MG are expected to
be mouth-formed.
3. Children and their parents are aware of the need for wearing MG during
training and matches. Parents know which type of MG their child is
wearing. Children like their MG and do not have any difficulties in
wearing them.
61 2 Chapter 2 Materials and Methods
2.1 Ethical Approval and Relevant Permissions
Ethical approval for this research was obtained from the Trinity College Dublin
Faculty of Health Sciences Research Ethics Committee (2nd November 2018, reference 180901 (Appendix 1)).
The Gaelic Athletic Association (GAA) and Ladies’ Gaelic Football Association
(LGFA) were contacted by letter (Appendix 2) to seek their support and endorsement for this research to be conducted among Gaelic football players.
Permission was granted by both organisations (Appendix 3; Appendix 4).
2.2 Study Design
A cross-sectional observational cohort study design has been employed for this study. Gaelic football teams were chosen as the target population because the
GAA introduced mandatory mouthguard (MG) rules in 2014 for players of all levels (Gaelic Athletic Association, 2017).
2.3 Study Population
2.3.1 Inclusion and Exclusion Criteria
Table 2.1 Inclusion and exclusion criteria
Inclusion Criteria Exclusion Criteria
Gaelic football players (boys and girls) No signed consent form from parents
Willing to participate Child unwilling to participate
Age: 9 – 16 years (2003 – 2010) Hurling/camogie players
Signed consent form from parents
62 2.3.2 Recruitment and Sampling
A convenience sample of boys and girls aged between 9 and 16 years of age
(born between 2003 and 2010), playing Gaelic football, was recruited via their
Gaelic football team for participation in this study along with their parents. The
GAA club contacted players and parents via email, text or social media to make them aware of the study. Posters were put up around each club on the night of data collection to generate awareness of the study. Players and parents presented themselves for participation. This may have led to sampling bias, whereby those children who were wearing their MG may have been more likely to present for participation in the study.
During the literature search, no other studies were found exploring both the compliance of children playing sports with MG rules and the characteristics
(retention, thickness, etc) of the existing MG worn by those children. A power calculation and sample size could not therefore be completed. The aim was to include as many children as possible, who were able to attend for a MG assessment along with their parents for consent purposes.
Fourteen GAA clubs were contacted to invite their players in the relevant age group to participate. Dates were agreed upon for club visits by the research team.
The goal was originally to examine 20 children per club. Responses were received from four clubs who agreed to participate. The goal was then adjusted to examine 30-50 children per club, depending on uptake.
63 2.4 Consent
A gatekeeper at each club (the Public Relations Officer (PRO)) shared participant information leaflets (PILs) (Appendix 6; Appendix 7) and consent forms
(Appendix 8; Appendix 9) with parents and players via email the week before the appointed date for club visit. There was a one-week cooling-off period between receiving the information and consent forms and data collection dates.
Two consent forms were signed by each parent; one for child participation and one for parent participation.
2.5 Parent and Child Questionnaires
The parent questionnaire (Appendix 10) was formulated based on a questionnaire published by a previous Irish study investigating attitudes to MG use in Ireland (O’Malley et al., 2012). This questionnaire was modified to include additional questions in relation to MG hygiene and how much parents would be prepared to pay for a MG to protect their child’s teeth. In total, there were 17 items on the parent questionnaire, with a combination of multiple choice and open- ended questions.
The child questionnaire (Appendix 11) was also based on the questionnaire from the same study (O’Malley et al., 2012). Questions were added to determine how each child felt about wearing their MG (i.e. comfort, ability to speak, ability to breathe) and how MG hygiene was achieved. There were 21 items on the child questionnaire, with a combination of multiple choice and open-ended questions.
64 2.5.1 Pilot Parent Questionnaires
Permission was obtained from the Executive Committee of the Dublin Dental
University Hospital to conduct a pilot survey of parents attending with their children for treatment on the undergraduate and postgraduate paediatric dentistry clinics in September 2019. This was to assess the language used for the questions and ensure that the questionnaire was understandable.
Minor language and format adjustments were made to ensure clarity of the questionnaire before beginning data collection.
2.5.2 Completion of Parent and Child Questionnaires during Data
Collection
Parents were given hard copies of the parent questionnaire to completed themselves whilst the children were being examined. The time taken to complete the questionnaire was approximately 5 minutes.
The “recorder” from the examiner team verbally asked each child the questions from the child questionnaire after the MG assessment was completed, and the recorder transcribed the child’s answers on to a hard copy of the child questionnaire. The time taken to complete this survey was approximately 5 minutes.
2.6 Assessment of Child’s Mouthguard and Dentition
The permanent anterior teeth for each child were examined visually to assess for any signs of previous dental injury (fractures, craze lines, discolouration, restorations, infraposition or missing tooth). The incisal overjet was visually estimated and recorded as being reduced, normal (average), or increased.
65 The criteria for the MG assessment were based on the findings from the literature as presented in Table 1.7 of the literature review. An examination sheet was formulated to facilitate recording of the findings of the dentist examination
(Appendix 12).
As a field study, and in the absence of a previous field assessment of MG quality, the principles of the retention assessment for the MG in this study were drawn from well-established complete denture retention assessment techniques, specifically regarding the relationship of denture flanges with oral soft tissue structures (vestibular reflection, frenal attachments). Children were asked to open their mouth with the MG in place, and if it fell down this was a clear indication of inadequate retention. If it remained in place, the buccal and labial soft tissues were manipulated in the same movements as for denture border moulding to assess whether or not the flanges of the MG were impinging on the soft tissues.
If they were, the MG would fall down, and this would indicate inadequate retention.
Thickness measurements were performed on the labial surfaces of the right and left canine and permanent incisor teeth, and on the occlusal surfaces of the right and left first permanent molar, canine and central incisor teeth (Table 2.2; Figure
1).
Table 2.2 Measurement locations on mouthguards
Thickness Teeth measured
Occlusal 16 13 11 21 23 26
Labial - 13 11 21 23 -
66
Figure 1 Measurement locations on mouthguards
Mouthguard surface integrity was assessed by checking for obvious perforations, as well as assessing for smooth rounded borders and for any obvious deformations in the form of the MG. Occlusion was assessed by asking the child to bite on their MG while it was in situ, with a visual assessment of whether there was simultaneous, balanced occlusion on both sides of the MG, as well as occlusion of the lower anterior teeth against the anterior surface of the MG.
Mouthguard colour was assessed as being dark, light or transparent (clear). This was not a precise measurement and was dependent on individual examiner judgement of the colour. Examples of dark colours were dark blue, dark green, black, brown; light colours were those such as white, yellow, red, light blue, light green.
The time taken for the assessment of the child’s dentition and their MG was approximately 5 minutes.
67 2.7 Equipment
The callipers used to measure the MG in this study was an external gauge digital callipers correct to 0.1mm (IGaging® 8” Digital Outside Callipers, California, USA;
Figure 2). The tip of these callipers was thinned on one side using a lathe to ensure precision of measurement within the MG.
Figure 2 Callipers used in this study
The callipers were each calibrated before and after this adjustment using a 25mm gauge block (Micrometer Setting standard 167-101, Mitutoyo Corporation,
Kawasaki, Japan; Figure 3) to ensure accuracy and reproducibility of measurement.
Figure 3 Demonstration of calliper calibration using gauge block
68 2.8 Training and Calibration Exercise
Training and calibration exercises were carried out at the Dublin Dental University
Hospital, with a three-month break between calibration measurements. A male adult volunteer agreed to have stock (SMG) and mouth-formed (MFMG) mouthguards purchased to fit him, and to have alginate impressions made to facilitate fabrication of a selection of custom MG (CMG) (Table 2.3).
Table 2.3 Mouthguards used for calibration exercise.
Mouthguard Trade name Further information type Stock OPRO® Snap-Fit Junior Moulded to fit according to Mouth-formed Shock Doctor V2 Gel Max manufacturer instructions
Erkoflex 4.0mm dark blue EVA Custom 1 (Erkodent®, Germany) Single-layer vacuum-formed mouthguards with intentional Erkoflex 4.0mm transparent deficiencies Custom 2 EVA (Erkodent®, Germany)
Bilayer vacuum-formed Erkoflex 4.0mm dark blue EVA Custom 3 mouthguard fabricated according (Erkodent®, Germany) to “ideal” criteria
Three CMG were fabricated according to specific prescriptions to the dental laboratory. One “ideal” and two “inadequate” MG were requested. The “ideal”
CMG (Table 1.7 (Chapter 1), Figure 5(a)) was fabricated via a double-layered vacuum-forming technique, using Erkoflex® 4.0mm dark blue ethylene vinyl acetate (EVA) blanks (Erkodent®, Germany). The other, “inadequate”, CMG were fabricated using the vacuum-forming technique, with intentional deficiencies
(Figure 4). One of these was made with the same dark blue EVA blank as the
“ideal” MG, but in a single layer (Figure 5(b)). The other was made using a transparent EVA blank, again in a single layer (Figure 5(c)). Stock and MFMG used are seen in Figures 5(d) and 5(e).
69
Figure 4 Laboratory prescription for inadequate mouthguards
Figure 5 Calibration Mouthguards. (a) Ideal custom MG. (b) Non-ideal, dark custom MG. (c) Transparent custom MG. (d) Stock MG. (e) Mouth-formed MG.
Five examiners were trained in examining a subject’s dentition for signs of trauma. Training was provided using a PowerPoint presentation with a variety of images of different traumatic injuries and their sequelae. Examiners were assessed and calibrated for agreement on correctly identifying signs of injury.
70 Examiners were familiarised with the proposed flow of the club visit from arrival to departure, completion of the consent forms and questionnaires, and in the cross-infection control procedures (section 2.8).
Examiners were trained to carry out the MG examination: assessing type, fit, retention and colour of each MG. The examiners were also trained in the use of the callipers using the gauge block. They were trained in how to use the digital display, especially in how to zero the reading in between each measurement.
Examiners were trained on correct location points to measure on each MG (table
2.2; figure 1). Measurements were corrected to 0.1mm.
Mouthguards fabricated or modified for the purposes of the calibration exercise were numbered from 1-5. Examiners were assessed in identifying traumatic injuries from slides; and in assessing and measuring the thickness of each MG.
Three examiners were selected to carry out the assessment and measurement of MG due to examiner availability for each data collection visit. The initial training exercise took place in June 2019. The first calibration exercise was undertaken in September 2019, with a repeat calibration exercise in January 2020. Statistical tests to establish intra- and inter-examiner agreement (Cohen’s kappa (훋), intraclass correlation coefficient) were carried out.
2.9 Cross-Infection Control Procedures
Examinations were performed on GAA club premises. To ensure compliance with universal precautions, personal protective equipment was utilised by the examiners. Disposable nitrile gloves (Transform® 100 Nitrile Powder Free
Gloves) were brought to the club and used for each subject. The tips of the
71 callipers were covered with PTFE tape as a physical barrier and these were changed in between each subject. The callipers were thoroughly disinfected using Clinell® Universal Wipes after each use. Clean and contaminated zones were kept separate; contaminated zones were designated through the use of a blue bib. Clinical waste (used gloves, Clinell® wipes, bibs and PTFE tape) was collected at each session and subsequently disposed of through the clinical waste disposal process at the Dublin Dental University Hospital. Alcohol hand gel was used to disinfect examiners’ hands in between each participant, and before and after carrying out cross-infection control procedures.
2.10 Data Collection Workflow
Data were collected on the premises of each participating GAA club. Examiners were covered under the Clinical Indemnity Scheme of the Dublin Dental
University Hospital and under each respective club’s public liability insurance.
The entire data collection workflow has been summarised and presented in Table
2.4.
At each club, consent forms and PILs were distributed electronically by the club
PRO and mentors among team members and their parents one week before the research team attended for data collection.
Data packs were prepared for each participant. These comprised a hard copy of the parent and child PIL and consent forms, the parent questionnaire, dentist examination sheet and child questionnaire. These were clipped together with paperclips and kept on clipboards along with a coloured card to denote which examining team they were to see. Once data collection was complete, the examining team placed coloured stickers on the data sheets to correspond with
72 their designated team colour to facilitate later coding of the data sheets. The parent questionnaire, child questionnaire and dentist examination sheet for each participant were stapled together and placed in a box of completed records.
Consent forms were placed separately in a sealed envelope.
2.10.1 Examiner Teams
Examiners worked in teams of two. One person examined the child, measured
MG thickness, and carried out cross-infection control procedures. The other person checked that consent forms were properly completed, provided the parent questionnaire to the accompanying parent to complete, recorded the findings of the examiner on the dentist examination sheet, and completed the child survey with the child.
Each team was assigned a colour (i.e. blue team, green team, orange team). This was designated with a coloured sign on the wall beside their examining station.
Participants were given a coloured card along with their data packs on arrival at the data collection location corresponding with the examining team that would see them. This was to keep the system organised and efficient.
2.10.2 Examining Stations
Each examiner had a station (Figure 6) set up with 3 chairs, a table, a bin with a yellow “contaminated” bin and the supplies necessary for data collection (Figure
7): box of gloves, disinfectant wipes (Universal Sanitising Wipes, Clinell®, GAMA
Healthcare Ltd., Hertfordshire, UK), alcohol hand gel (PURELL® Advanced
Hygienic Hand Rub, GOJO Industries, Frankfurt, Germany), PTFE tape, blue bibs to denote the contaminated zone and callipers (IGaging® 8” Digital Outside
Callipers, California, USA).
73
Figure 6 Equipment needed for data collection
Figure 7 Data collection set up at GAA club
74 Table 2.4 Detailed description of data collection workflow and data management
1 week prior to data collection
GAA club shared participant information leaflets with parents and children via email ± follow- up reminders via text, WhatsApp, or social media (Twitter, Facebook, Instagram)
At the time of data collection
Preparation Examining teams set up 2 examining stations in location at the GAA club agreed upon with each Club Child Safety Officer and Public Relations Officer.
Each team had an “examiner” – examined child, assessed mouthguard, and carried out cross infection control – and a “recorder”, who recorded findings/measurements called out by examiner, and asked the child the questions from the child questionnaire.
Stations were colour coded to allow organisation of the data collection system.
Posters were put up around the club house and grounds to remind players and parents of the study.
Players’ and Players & parents presented themselves for participation in the study parent’s arrival Each pair was handed a clipboard with:
• Parent and child participant information leaflets • Parent and child consent forms • Parent and child questionnaires • Dentist examination sheets • Coloured card to denote the team to attend for examination
Players & parents queued to be seen by exam team.
Upon seating Parents given parent questionnaire – self completed hard copy of at examination questionnaire. station Child sat with the team for examination.
Examination sequence:
1. Child asked to open mouth 2. Examiner assessed dentition stage, incisal overjet using visual estimation, signs of trauma 3. Child asked to put mouthguard in mouth. 4. Examiner assessed mouthguard type, retention, labial and palatal extension, occlusal coverage, and occlusion. 5. Child asked to remove mouthguard. 6. Examiner assessed mouthguard surface for damage, colour and deformations. 7. Examiner measured mouthguard thickness at designated sites & gave mouthguard back to child. Whilst the examiner performed cross infection control, the recorder asked the child the questions on the child questionnaire.
75 After Cross infection control verified. completion of examination Consent forms placed in sealed envelope. and Remaining paperwork pertaining to the player-parent pair (dentist questionnaires examination and child & parent questionnaires) stapled together and a coloured sticker placed on each page to denote the examining team to facilitate later coding.
Data sheets coded according to the name of the club, the name of the examiner, and a number in sequence e.g. CGES01 = Clanna Gael Fontenoy, Elaine Shore, Player #1
After Data Collection
Data input - Child and parent questionnaires formatted in SurveyMonkey. questionnaires Responses to surveys manually input into SurveyMonkey by principal investigator (E. Shore) after each data collection session.
Data input double-checked on summary of each questionnaire on SurveyMonkey to verify accuracy before moving on to the next questionnaire.
Once all data collection was finished, the results collated in Survey Monkey were exported as Excel spreadsheet files.
Data input – Data from each dentist examination sheet was manually tabulated in an dentist Excel spreadsheet after each data collection session by the principal examination investigator (E. Shore). sheets Data input double-checked at the end of each line in the spreadsheet to verify accuracy before moving on to the next examination sheet.
Preparation of All 3 spreadsheets were merged into 1 spreadsheet using the participant data for coding as a means of linking together the player questionnaire, parent statistical questionnaire and dentist examination sheet for each participant. analysis Data were coded where necessary (e.g. 0 = no, 1 = yes) to facilitate input to SPSS for statistical analysis.
2.11 Statistical Analysis
Both calibration and clinical data collected during this study were tabulated in a spreadsheet using Excel (Microsoft Corporation, 2018). This data was then exported from Excel into SPSS (Statistical Package for Social Sciences (SPSS) version 26 (IBM Corp., Chicago IL, USA), where it was then analysed. Missing data (i.e. missed answers) were excluded from the data analysis; this was done
76 automatically by SPSS. The remaining data were included in all other analyses and no subject was excluded on the basis of missing data in questionnaires.
2.11.1 Calibration
Data for each examiner was recorded on calibration sheets and analysed using
SPSS. Inter- and intra-examiner agreement was calculated using intraclass correlation coefficient (ICC) for quantitative variables, and Cohen’s Kappa coefficient (훋) was calculated for qualitative variables.
2.11.2 Descriptive analysis
Variables relating to MG, children and their parents were analysed. The total number and percentages were calculated for each categorical variable.
Quantitative data were tested for normality using the Kolmogorov-Smirnov test.
For quantitative data with a normal distribution, the mean and standard deviation were established and reported. For quantitative data which were not normally distributed, the median and interquartile range were established and reported.
The nature of the distribution of the data determined whether parametric or non- parametric statistical tests were used.
Statistical tests were also chosen based on whether it was a comparison of independent variables or paired samples such as comparing answers provided by parents and children to the same or similar questions. For comparisons involving two independent variables, the Student t test was used for parametric variables and Mann-Whitney U test for non-parametric variables. For comparisons involving greater than 2 independent variables, one-way ANOVA
77 was used for parametric variables and Kruskal-Wallis test for non-parametric variables.
Agreement between participant responses to similar questions was calculated using kappa analysis. Chi square analysis was performed to investigate the influence of MG characteristics on MG retention.
Binary logistic regression analysis was performed to analyse the association between the dependent variables (player compliance with GAA MG rules during training sessions) and independent variables (age, gender, MG type, labial and palatal extension, retention, balanced occlusion, average labial thickness, average posterior occlusal thickness, number of sports played, number of sports for which MG is worn, ability to talk and breathe while wearing MG, whether or not the taste of their MG was satisfactory, whether they liked or disliked their MG, who chose their MG, how old their MG was, and any self-reported history of dental trauma). Variables which displayed an association with a significance level of p < .20 in the univariate analysis were brought forward for inclusion in the adjusted analysis. The adjusted model was a forward stepwise binary logistic regression analysis.
Linear regression analysis was performed to evaluate the association between the price parents were willing to pay for a CMG, and both parent-reported independent variables (whether the MG is worn for some or all sports, number of sports with MG rules according to parents, whether or not their child wears the
MG for Gaelic football training, and which type of MG the parent believes will best protect their child’s teeth) and child characteristics (age, gender).
78 3 Chapter 3 Results
3.1 Calibration
Following the calibration sessions, inter-rater agreement for qualitative variables
(identifying signs of dental trauma, assessing retention and extension of mouthguard (MG)) was high (훋 > 0.8). Inter-rater agreement for MG thickness was also high, measured by the intraclass correlation coefficient estimate based on a mean-ranking (k=3), absolute agreement, one-way random effects model
(Table 3.1) (Koo and Li, 2016).
Table 3.1 Inter-rater reliability for mouthguard thickness measurements
Intraclass 95% confidence p-value correlation interval coefficient
Labial thickness 0.953 0.905-0.980 <.001 measurements
Occlusal 0.861 0.763-0.926 <.001 thickness measurements
Intra-rater reliability was also measured using the intraclass correlation coefficient estimate based on a mean-ranking (k=3), absolute agreement, one-way random effects model (Table 3.2) (Koo and Li, 2016). Reliability was high (> 80%) for labial measurements; in the case of occlusal thickness measurements, reliability was high for examiners 1 and 2 (≥ 80%) but was only 47.5% for examiner 3 (table
3.2).
79 Table 3.2 Intra-rater reliability measurements for labial and occlusal mouthguard thickness
Thickness Intraclass correlation 95% confidence p-value measurements coefficient interval
Examiner 1
Labial 0.908 0.783-0.963 <.001
Occlusal 0.799 0.620-0.899 <.001
Examiner 2
Labial 0.918 0.804-0.983 <.001
Occlusal 0.926 0.850-0.964 <.001
Examiner 3
Labial 0.819 0.598-0.924 <.001
Occlusal 0.475 0.144-0.719 .003
3.2 Characteristics of the sample
Fourteen Gaelic football teams were invited to participate in the study. Four clubs agreed to take part (Table 3.3). Each club provided the lead investigator with a date and time which was most convenient for them to facilitate data collection at the club. The sample was therefore influenced by the teams which were training on that particular night. Data collection was completed between September 2019 and January 2020.
Parental consent for participation in the study was granted for a total of 121 children aged between 9 and 16 years playing Gaelic football across the four clubs. All 121 participants presented for the oral examination. Parental questionnaires were not completed for 3 participants, and 1 child did not fully complete the child questionnaire. This incomplete data was excluded from the analysis of the respective questionnaires, but the data from all examinations were retained for inclusion in the analysis.
80 Table 3.3 Description of sample distribution, by club
Club Visit Date(s) Participants (N)
Clanna Gael Fontenoy, Ringsend, Dublin September 2019 x2 N = 40 4
St. Vincent’s, Marino, Dublin 3 October 2019 x2 N = 46
Ballymun Kickhams, Ballymun, Dublin 9 November 2019 x1 N = 16
Good Counsel, Drimnagh, Dublin 12 January 2020 x1 N = 19
3.2.1 Age
The age range of the participants was 9-16 years old. The mean age was 11.99 years (median age 12 years; interquartile range (IQR) = 10-13). The distribution of participant ages was not normally distributed (Kolmogorov-Smirnov test, p =
<.001; Figure 8). There were slightly more males (N = 68, 56.67%) than females
(N = 52, 43.33%).
Figure 8 Age distribution of study participants
81 3.2.2 Reported past trauma experience
Using the questionnaire, children and their parents were each asked if they recalled any previous incident when there was an injury to the child’s permanent teeth (Table 3.4). Twenty-one children (17.5%) reported at least one past injury to their permanent teeth. Of these, 12 (57.14%) reported that this injury had happened while playing sports, which corresponds to 9.9% of the entire sample.
The majority of these children (N=10, 83.33%) reported wearing a MG at the time of injury. The reported mean age at the time of the trauma was 9.53 ± 1.98 years.
Only eight parents (6.78%) reported a past trauma to their child’s teeth, with 3 of these (37.5%) reportedly having suffered the injury while playing sports, none of whom were reported to be wearing their MG at the time (Table 3.4).
Agreement between parent and child responses was poor in relation to any past history of trauma, and this was significant (훋 = 0.445, p < .001). While there was also a difference in reports relating to trauma during sports, this was not statistically significant (훋 = 0.417, p = .270; Table 3.4).
Table 3.4 Child and parent reports of past episodes of trauma to permanent teeth
Children Parents 훋 p
Reported trauma to permanent teeth, 21 (17.5) 8 (6.78) 0.445 < .001* N(%)
Trauma during sports 12 (54.5) 3 (37.5) 0.417 0.27 (SRDI), N(%)
N(%) of total sample 12 (9.9) 3 (2.54) - - reporting SRDI
N(%) wearing MG at 10 (83.3) 0 (0.00) - - time of injury
82 3.2.3 Signs of trauma
During the oral examination, there were signs of trauma observed in 12.4% of the sample (15 children). Ten of these had enamel fractures, which represented two- thirds of those with signs of trauma (66.67%). One participant had an unrepaired enamel-dentine fracture, three had class IV composite restorations on at least one of their front teeth, and one participant had an upper central incisor which appeared to be extruded relative to the adjacent teeth. There were no missing anterior teeth due to trauma in this sample.
There was a significant difference between the child-reported trauma history with the dentist-observed signs of trauma in the participant’s teeth. The agreement between child-reported history of trauma and dentist-observed signs of trauma was low at only 23.6% (훋 = 0.236, p = .008). One of the children in whom signs of trauma were observed over the course of the examination did not complete the child questionnaire (N=14). Agreement between parent-reported trauma history and dentist-observed clinical signs of trauma was poor but this did not reach statistical significance (훋 = 0.093, p = .286; Table 3.5).
Table 3.5 Child-reported signs of trauma compared to dentist-observed signs of trauma.
Dentist-observed clinical signs of trauma
No N (%) Yes N (%) Total N (%) 훋 p
Child- No N (%) 91 (91.9) 8 (8.1) 99 (100) reported history of Yes N (%) 15 (71.4) 6 (28.6) 21 (100) 0.236 .008* dental trauma Total N (%) 106 (88.3) 14a (11.7) 120 (100)
Parent- No (N, %) 96 (88.1) 13 (11.9) 109 (100) reported history of Yes (N, %) 6 (75.0) 2 (25.0) 8 (100) 0.093 .286 dental trauma Total 102 (87.2) 15 (12.8) 117 (100)
83 3.2.4 Incisal Overjet
Forty-seven percent of the sample had an average (normal) incisal overjet
(defined as an overjet of 1-3mm). A similar proportion (44.6%) had an increased overjet, while only 8.3% had a reduced overjet. The majority of the signs of trauma were in those participants with increased overjet (10 participants;
66.67%); 8 of these had enamel fractures, and 2 of these had class IV composite restorations. Due to the small number of participants involved, a statistical conclusion could not be drawn.
3.3 Sports participation, knowledge and behaviours in relation
to mouthguard use
3.3.1 Reported level of participation in sports
The vast majority of the sample (93.6%) reported playing more than 1 sport, with
62.9% of the sample (almost two-thirds) reporting participating in 2-3 sports.
Similarly, the majority (90.9%) reported playing more than 1 contact sport; 80.2% play 2-3 contact sports (Table 3.6).
Table 3.6 Level of sports participation among the sample
Number of sports played Number of contact sports played
Mean 3.07 2.43
Median 3.00 2.00
Std. Deviation 1.367 0.805
Range 6 4
Every participant played Gaelic Football and two-thirds of the sample also played hurling or camogie; this is unsurprising as these sports are also under the
84 auspices of the Gaelic Athletic Association. Soccer (23.97%), hockey (22.31%), swimming (20.66%) and basketball (19.00%) were also popular sports. Only eight participants (6.61%) reported playing rugby. Other sports undertaken by participants included athletics, equestrian sports and gymnastics (in “other” category, 24.79%). This is illustrated in Table 3.7.
Table 3.7 Level of sports participation, as a percentage of the total sample.
Number of children (% of total Sport played sample)
Gaelic football 121 (100%)
Hurling/Camogie 81 (66.94%)
Soccer 29 (23.97%)
Hockey 27 (22.31%)
Rugby 8 (6.61%)
Basketball 23 (19.00%)
Boxing/Martial Arts 5 (4.13%)
Tennis 17 (14.04%)
Swimming 25 (20.66%)
Other 30 (24.79%)
3.3.2 Parent and child knowledge of mouthguard rules in sports besides
Gaelic football
For those children playing hockey (N=27), the majority of parents (N=23/27,
85.19%) and all but one of the children (N=26/27, 96.3%) reported the existence of rules for MG use in hockey. High rates were also observed in rugby for parent
(N=7/8, 87.5%) and child (N=7/8, 87.5%) report of MG rules for that sport. It was reported that 5 children participated in boxing/martial arts. Three of the parents
85 (60%) and 2 of the children (40%) reported that MG were required for these sports.
3.4 Player compliance with GAA mouthguard rules
3.4.1 Parent-reported child compliance with rules
All parents reported that their child wears a MG for sports. The parent questionnaire asked, in one single question, if their children wore their MG for
Gaelic football training only, for training and matches, or for matches only. The majority of parents who participated in the questionnaire (N = 105/118, 91.53%) reported that their children were wearing their MG for Gaelic football training and matches; i.e. full compliance with GAA MG rules. Twelve parents (10.17%) reported that their child wore the MG for Gaelic football matches only. There were no reports of children wearing their MG for training only.
3.4.2 Child-reported compliance with GAA mouthguard rules
Children were asked if they wore their MG for training and for matches as two separate questions. One child did not respond to this question. One hundred and nineteen children (99.17%) reported wearing their MG for Gaelic football matches. For Gaelic football training, ninety-seven players (80.83%) reported that they wear their MG routinely. This is a reduction in compliance of 18.34%% compared to the compliance rate for Gaelic football matches. Table 3.8 describes the distribution of players according to age and gender, and whether or not they wear their MG during Gaelic football training.
86 Table 3.8 Proportion of players wearing and not wearing MG during Gaelic football training, according to age and gender
Age 9-10 years Age 11-12 years Age 13-14 years Age 15-16 years
Male Female Male Female Male Female Male Female
Wearing 16 20 9 23 17 6 4 1 MG (N%) (100.0%) (100.0%) (90.00%) (100.00%) (85.00%) (100.00%) (18.18%) (50.00%)
Not 0 0 1 0 3 0 18 1 wearing (0.00%) (0.00%) (10.00%) (0.00%) (15.00%) (0.00%) (81.82%) (50.00%) MG (N%)
Total (N) 16 20 10 23 20 6 22 2
36 33 26 24
3.4.3 Factors influencing the rate of compliance with mouthguard wear for
Gaelic football training
A binary logistic regression analysis was completed to investigate if the reduction in compliance during training compared to matches was influenced by player- or
MG-related factors (Table 3.9). The dependent variable (outcome) was compliance with GAA MG rules during training sessions, as determined by answers from the child questionnaire. The univariate analysis included the following independent variables: child age, child gender, MG type (stock, mouth- formed, custom), labial extension, palatal extension, retention, balanced occlusion, average labial thickness, average posterior occlusal thickness, the number of sports played, the number of sports for which a MG is worn, ability to speak with MG in place, ability to breathe with MG in place, taste of MG, whether they liked or disliked their MG, who chose their MG, MG age and self-reported past history of dental trauma.
In the univariate analysis, there was an association between several factors and compliance with MG wear for training (Table 3.9). Older children were less likely to comply with MG rules during training (OR = 0.23, p < .001). Females were 11
87 times more likely to comply with MG rules during Gaelic football training sessions, when compared to males (p = .002). Children who participated in greater numbers of sports were more likely to wear their MG during training (OR = 1.85, p = .009). Children whose MG had inadequate palatal extension in the MG assessment were 88% more likely to wear their MG during training compared to those with adequate palatal extension (OR = 0.12, p = .047). Children whose MG were thicker in the region of the first permanent molars were more likely to comply with GAA rules for MG wear during training (OR = 1.53, p = .036). If they could speak with their MG in place, they were almost 4 times more likely to wear their
MG during training (OR = 3.81, p = .006), and compliance was similarly greater for those who felt they could breathe properly with their MG in situ (OR = 5.11, p
= .017). Children who felt that their MG tasted “okay” were more likely to wear their MG during training than those who did not (OR = 3.07, p = .053). Overall, children who reported disliking their MG were almost 4 times less likely to comply with GAA MG rules during training (OR = 3.95, p = .005).
An adjusted model was compiled using the factors which had associations with compliance in the univariate analysis (age, gender, palatal extension, average occlusal thickness posteriorly, ability to speak and breathe with MG in place, taste of MG, who chose the MG, number of sports played, like/dislike MG; Table 3.9).
In this model, age was the only factor to retain its association with MG compliance
(OR = 0.18, p < .001). Therefore, older children are less likely to comply with MG rules for training, with a reduction in compliance of 82% with each increase in age by one year. The Hosmer and Lemeshow goodness-of-fit test was non-significant
(p = .668) and Nagelkerke’s pseudo R2 was 0.683, indicating that age is a moderate predictor of compliance.
88 Table 3.9 Binary logistic regression analysis investigating factors influencing player compliance with MG rules during Gaelic football training sessions.
Not OR OR Wearing Total Variable wearing Univariate p Adjusted p N (%) (N) N (%) (95% CI) (95% CI) Age of child Continuous – 14.87 11.27 0.23 .000* 0.18 .000* Mean (SD) (0.92) (1.81) (0.13-0.41) (0.08-0.44) Gender Male (ref) 21 (31.3) 46 (68.7) 67 - - - - Female 2 (3.8) 50 (96.2) 52 11.41 .002* 2.49 .344 (2.54-51.39) (0.38-16.51) MG Type Stock (ref) 2 (6.5) 29 (93.5) 31 - .546 - - Mouth-formed 9 (12.9) 61 (87.1) 70 0.47 .350 - - (0.1-2.30) Custom 1 (20.0) 4 (80.0) 5 0.28 .335 - - (0.20-3.78) Labial extension Inadequate 10 (11.4) 78 (88.6) 88 0.96 .962 - - (ref) (0.19-4.84) Adequate 2 (11.4) 15 (88.2) 17 Palatal extension Inadequate 1 (2.4) 40 (97.6) 41 - - - - (ref) Adequate 11 (17.2) 52 (82.8) 64 0.12 .047* 0.1 .132 (0.02-0.97) (0.01-2.01) Retention Inadequate 9 (10.6) 76 (89.4) 85 - - - - (ref) Adequate 3 (15.0) 17 (85.0) 20 0.67 .579 - - (0.16-2.74) Balanced occlusion Inadequate 4 (7.1) 52 (92.9) 56 - - - - (ref) Adequate 8 (17.0) 39 (83.0) 47 0.38 .130 - - (0.11-1.34) Average labial thickness Continuous – 4.24 (0.91) 4.18 0.96 .882 - - Mean (SD) (1.15) (0.57-1.63) Average occlusal thickness posteriorly Continuous – 3.45 (1.93) 4.79 1.53 .036* 1.23 .453 Mean (SD) (1.93) (1.03-2.28) (0.71-2.14)
89 Number of sports played Continuous – 2.39 (1.12) 3.25 1.85 .009* 1.21 .531 Mean (SD) (1.34) (1.17-2.93) (0.66-2.23) Number of sports where mouthguard is worn Continuous – 1.22 (0.52) 1.43 2.10 .117 1.27 .741 Mean (SD) (0.59) (0.83-5.31) (0.31-5.31) Ability to talk while wearing mouthguard No (ref) 15 (31.9) 32 (68.1) 47 - - - - Yes 8 (11.0) 65 (89.0) 73 3.81 .006* 2.95 .146 (1.46-9.92) (0.69-12.68) Ability to breathe while wearing mouthguard No (ref) 5 (50.0) 5 (50.0) 10 - - - - Yes 18 (16.5) 92 (83.6) 110 5.11 .017* 0.63 .597 (1.34-19.5) (0.11-3.48) Does the mouthguard taste okay? No (ref) 6 (37.5) 10 (62.5) 16 - - - - Yes 17 (16.3) 87 (83.7) 104 3.07 .053* 3.52 .202 (0.98-9.58) (0.51-24.29) Like/dislike mouthguard Dislike (ref) 12 (36.4) 21 (63.6) 33 - - - - Like 11 (12.6) 76 (87.4) 87 3.95 .005* 2.03 .333 (1.53-10.21) (0.48-8.56) Person who chose mouthguard Player (ref) 16 (29.1) 39 (70.9) 55 - .033* - .378 Parent 5 (9.8) 46 (90.2) 51 3.77 .017* 1.7 .530 (1.27-11.24) (0.33-8.87) Other 1 (8.3) 11 (91.7) 12 4.51 .165 7.55 .189 (0.54 – (0.37- 37.91) 153.63) Age of mouthguard 0-6 months 10 (14.5) 59 (85.5) 69 - .317 - - (ref) 7-12 months 5 (23.8) 16 (76.2) 21 0.54 .321 - - (0.16-1.81) >12 months 8 (26.7) 22 (73.3) 30 0.47 .154 - - (0.16-1.33) Self-reported history of previous dental trauma No (ref) 21 (21.2) 78 (78.8) 99 - - - - Yes 2 (9.5) 19 (90.5) 21 2.56 .230 - - (0.55-11.87)
90 3.5 Patterns of mouthguard wear for other sports
Children and their parents were surveyed in relation to the wearing of MG in sports besides Gaelic football. All parents answered this question (N = 118).
Thirty-two parents (27.11%) reported that their children wear their MG for all sports. Only 17 children (14.05%) reported that they wear their MG for all sports.
Agreement between child and parent reports of MG wear for other sports was low
(훋 = 0.271, p = .001) and there was a significant difference between parent and child answers for this question (Mc Nemar’s test, 훘2 = 6.76, p = .009; Table 3.10).
The majority of children (n = 104; 86%) are wearing MG for a mean number of
1.40 ± 0.58 sports.
Table 3.10 Comparison of parent and child reports of MG wear for some versus all sports.
Child: Wearing MG for some
vs all sports
Some N (%) All N (%) Total N (%)
Parent: Some N (%) 79 (78.2) 7 (41.2) 86 (72.9) Wearing MG for some vs All N (%) 22 (21.8) 10 (58.8) 32 (27.1) all sports Total 101 (100) 17 (100) 118 (100)
Mouthguards are generally worn for hockey, rugby, and boxing/martial arts in
Ireland. Among hockey players, 27 children reported playing the sport and 21 of these (77.78%) reported wearing MG for hockey. For rugby, 7 out of the 8 children playing this sport reported wearing MG (87.5%). However, for martial arts, only 2 of the children (40%) reported that they were wearing MG.
91 Of those who reported only wearing their MG for some sports (N = 104), just over half reported that this was because MG were not required for those sports (N =
55, 52.88%). Thirty-five children who played hurling/camogie reported that a MG was not required as they wear a helmet for this sport. Other reasons supplied by the other twelve children (11.54%) included “not a contact sport” (N = 6, 5.76%), an inability to wear the MG at any time due to discomfort (N=1), “not allowed” to wear it for other sports (N=1), and “don’t know” (N=2). No answers for this question were given by the final 2 participants.
Those who stated they did not wear MG for other sports because they were either non-contact sports, or there were no rules for MG wear in those sports, included children who did play contact sports. Of the 29 children who reported playing soccer, only 3 children (10.34%) reported wearing their MG for this sport.
Similarly, only 1 child reported wearing a MG for basketball out of a total of 23 children playing that sport (4.35%).
3.6 Child and parent attitudes and behaviours in relation to
mouthguard use
3.6.1 Child attitudes and experiences
One hundred and twenty children responded to the questions relating to their attitudes and experiences of wearing a MG; one child declined to complete these questions. The majority of children stated that they had no issues with breathing while wearing the MG (N=110, 91.67%) and that they had not experienced a poor taste from their MG (N=104, 86.67%). Forty-seven children (39.17%) reported that they had difficulty speaking while wearing their MG.
92 Overall, when asked whether they liked or disliked their MG, almost three quarters of the children reported that they liked their MG (N = 87, 72.50%). This was unrelated to the type of MG worn (훘2= 1.628, p = .443; Table 3.11). However, the association between their ability to breathe while wearing their MG and their affinity for the MG was significant (훘2 = 15.081, p < 0.001; Table 3.11). There was also a significant association between their ability to speak while wearing the MG and whether or not they liked it (훘2= 8.781, p = .003; Table 3.11).
Table 3.11 Chi-square analysis of association between mouthguard type, ability to speak and ability to breathe with whether the child likes or dislikes their MG.
Child: Like/Dislike MG 훘2 p Total N No N (%) Yes N (%) (%)
Stock 9 (29.0) 22 (71.0) 31 (100.0)
Mouth- 17 (24.3) 53 (75.7) 70 (100.0) MG formed Type 1.628 .443 Custom 0 (0.0) 4 (100.0) 4 (100.0)
105 Totala 26 (24.8) 79 (75.2) (100.0)
No 20 (42.6) 27 (57.4) 47 (100.0) Ability to speak while Yes 13 (17.8) 60 (82.2) 73 (100.0) 8.781 .003* wearing MG 120 Total 22 (27.5) 87 (72.5) (100.0)
Ability No 8 (80.0) 2 (20.0) 10 (100.0) to breathe 110 Yes 25 (22.7) 85 (77.3) 15.081 <.001* while (100.0) wearing 120 MG Total 33 (27.5) 87 (72.5) (100.0) aTotal = 105 for this comparison because only 105 of the children surveyed had brought their MG for assessment.
93 3.6.2 Parent attitudes towards mouthguards
Parents were asked which types of MG they believed would sufficiently protect their children’s teeth in the event of a sports-related dental injury (Table 3.12).
Many parents indicated more than one type of MG as their response to this question. The majority (N = 87, 74.36%) believed that CMG would protect their child’s teeth (Table 3.12).
Table 3.12 Distribution of parents’ opinion on the protection afforded by various types of MG.
Frequency (N, % of parent Mouthguard type questionnaires)
Stock 10/118 (8.47%)
Boil and bite 49/118 (41.53%)
Custom 87/118 (73.73%)
Parents indicating 2 types of MG 17/118 (14.41%)
Parents indicating all 3 types 5/118 (4.24%)
Parents were also asked to indicate by making a mark along the length of a 10cm line how much they would be willing to pay (between €0 and €100) for a CMG for their child. The distance along the line from 0 (€0.00) to the point indicated was measured using a 15cm ruler, and the distance in centimetres was calculated as a percentage of 10cm (€100.00). This data was not normally distributed (p <
0.001). The results show that parents would be willing to pay a median price of
€35.00 (IQR = €20.00 - €50.00) for such a MG (Figure 9).
94
Figure 9 Boxplot of the data for the price parents were willing to pay for a custom mouthguard.
A linear regression analysis was carried out to investigate which factors, if any, influenced the price parents were willing to pay for a CMG (Table 3.13). The data for the price was not normally distributed, so it was transformed to the normal score of price using Blom’s formula. This normalised price was used for the linear regression analysis.
The independent variables in the univariate analysis were child age, gender, whether the child wore their MG for some or all sports, number of sports with MG rules, level of compliance with GAA MG rules, and any past history of injury to their child’s teeth.
It seems that parents were willing to pay almost 50% more for a CMG if their child was wearing it for all sports, compared to when children were wearing MG for only some sports. This was a very weak predictor of the price parents would pay for a CMG (R = 0.232, R square = 0.054). The linear relationship between these
95 variables was very weak (R2 = 0.084) so these results need to be interpreted with caution. A multivariate analysis was not possible with the current data.
Table 3.13 Linear Regression Analysis: Variables Influencing Price Parents Willing to Pay for Custom Mouthguard
휷-regression Cost willing to pay￥ Variable coefficient p- value Mean, SD (€) 95% CI Age of child￥ 0.099 Continuous Mean of sample .307 (-0.092 – 0.289) Gender Male (ref) 35.73 ± 14.48 - - 0.197 Female 43.63 ± 26.77 .269 (-0.154 – 0.548) Do they wear MG for some or all sports? Some (ref) 35.32 ± 16.28 - - 0.487 All 48.75 ± 27.61 .012* (0.109 – 0.864) Number of sports requiring MG￥ 0.207 Continuous Mean of sample .081 (-0.206 – 0.440) When do they wear MG for Gaelic football? Matches only (ref) 33.00 ± 14.23 - - -0.264 Training and matches 39.68 ± 21.34 .359 (-0.832 – 0.304) Past history of injury to permanent teeth? 0.440 Yes 48.50 ± 26.64 .203 (-0.241 – 1.121) No (ref) 38.29 ± 20.26 - - ￥Normalised equivalent of these variables using Blom’s formula used in the linear regression analysis.
3.6.3 Age of mouthguards being worn by the children
Parents and children were each asked a question in relation to the age of the MG
– that is, how long it had been since they first started using that particular MG.
One child did not answer this question. Seventy-seven parents (65.25%) and 69 children (57.5%) reported that their MG was 6 months old or less. Just under one quarter of parents (N = 27, 22.88%) reported that the MG was 7-12 months old,
96 compared to 17.5% of children (N = 21). Half as many parents as children reported that the MG was greater than 12 months old (Parents: N = 14, 11.86%;
Children: N = 30, 25.0%). Children and their parents agreed upon the age of the
MG just 58.6% of the time (훋 = 0.586, p < .001; Table 3.14).
Table 3.14 Agreement between child- and parent-reported MG age
Parent-reported
mouthguard age Total 훋 p 0-6 7-12 >12
months months months
0-6 59 67 Child- 7 (10.4) 1 (1.5) months (88.1) (100.0) reported 7-12 5 2 20 mouthguard 13 (65.0) months (25.0) (10.0) (100.0) age 0.586 <.001* >12 5 17 30 8 (26.7) months (16.7) (56.7) (100.0) 69 20 117 Total 28 (23.9) (59.0) (17.1) (100.0)
3.6.4 Mouthguard hygiene: storage and cleaning
Children and their parents were asked several questions to establish their level of knowledge in relation to MG hygiene (Table 3.15). One child did not complete these questions, but all parents completed these questions. Seventy-seven parents (65.25%) and 85 children (70.83%) reported that the MG was stored in a specific box when not in use. Of the remainder of the parents, 27 (22.88%) said the MG was kept loose in the gear bag, and 14 (11.9%) reported other locations such as various places in the home. Compared to the parent responses to the same questions relating to MG storage, 21 children (17.5%) reported keeping their MG loose in their gear bag, but a similar proportion reported keeping their
MG in “other” locations such as gloves or socks in between uses (N = 14,
11.67%). Parents and children were in agreement 56.3% of the time as to where the MG was stored when not in use (훋 = .563, p < .001; Table 3.15).
97 The response rate for questions in relation to MG cleaning was lower for the parent questionnaires than for the children’s questionnaires. Twenty parents
(16.5% of the total sample) did not answer the question in relation to how the MG was cleaned, and 13 (10.7% of the total sample) skipped the question in relation to the frequency of MG cleaning. One child did not answer the corresponding questions in the child survey. Assumptions cannot be made as to the nature of the missing data; for the purposes of the statistical analysis, subjects with missing data for these questions were excluded.
The question in relation to frequency of MG cleaning was asked as an open- ended question to avoid leading answers. The responses were coded into
“frequently” – corresponding to anywhere between “each use” to “monthly”, and
“rarely/never” – corresponding to anything less frequent than monthly, or those who stated they never clean the MG.
Of the parents who answered this question, less than two thirds (N = 68, 60.18%) reported that the MG is frequently cleaned, with 45 parents (39.82%) reporting it is rarely or never cleaned. Sixty-five children (54.16%) reported frequently cleaning their MG, while 55 children (45.83%) reported rarely or never cleaning it. Among the parent-child dyads for whom there were corresponding data
(N=112), there was agreement between parent and child responses only 41.4% of the time (훋 = .414, p < .001; Table 3.15).
An open-ended question was also asked to establish how MG were cleaned.
These responses were coded and grouped into categories (cold water, warm water, and other) according to the most common answers given by parents and
98 children. The “other” category included any use of soap or disinfectant such as household bleach, and use of toothbrush to clean the MG.
Of the 102 parents who answered this question, 63 parents (61.76%) reported that the MG is cleaned using cold water. Sixty-five of the 82 children who reported that they clean their MG (79.27%) also stated that they use cold water. Warm water was reportedly used to clean MG by 24 parents (23.53%) and by 10 children (12.50%). Sixteen parents (15.20%) reported using other methods besides water, including toothbrushes, toothpaste, soap, washing up liquid, and household bleach. Seven children (8.54%) described other methods of cleaning, including toothpaste and soap. Statistical analysis based on parent-child dyads for whom there were corresponding data showed that there was a significant difference between the parent and child answers for this question, with both parties in agreement on cleaning methods only 25.8% of the time (훋 = 0.258, p =
.001; Table 3.15).
99 Table 3.15 Agreement (훋) between parent and child answers relating to MG storage & hygiene
Parent Total 훋 p Child
Mouthguard Storage Mouthguard Loose in gear Other
Box N (%) bag N (%) N (%) Mouthguard box 68 (82.9) 12 (14.6) 2 (2.4) 82 (100) N (%) Loose in gear 5 (23.8) 14 (66.7) 2 (9.5) 21 (100) .563 <.001* bag N (%) Other N (%) 3 (21.4) 1 (7.1) 10 (71.4) 14 (100)
Total 76 (65.0) 27 (23.1) 14 (12.0) 117
Frequency of MG cleaning Frequently Rarely/Never - N (%) N (%) Frequently 49 (77.8) 14 (22.2) - 63 (100) N (%) .414 <.001* Rarely/Never 18 (36.7) 31 (63.3) - 49 (100) N (%) Total 67 (59.8) 45 (40.2) 112
Method of MG cleaning Cold water Warm Water Other
N (%) N (%) N (%) Cold water 43 (69.4) 9 (14.5) 10 (16.1) 62 (100) N (%) Warm Water 1 (14.3) 5 (71.4) 1 (14.3) 7 (100) .258 .001* N (%) Other N (%) 3 (50.0) 1 (16.7) 2 (33.3) 6 (100)
Total 47 15 13 75 3.7 Characteristics of Mouthguards worn by sample
3.7.1 Types of mouthguards worn by participants
The majority of participants (N = 106, 87.6%) had their MG with them on the day of training for assessment. Of these, the most popular type of MG was the MFMG, worn by two-thirds of the total sample (N = 71, 66.98%; Figure 11). Thirty-one participants (29.25%) wore SMG, while only 4 participants (3.77%) wore CMG
(Figure 10).
100
Figure 10 Types of MG worn by participants as identified by dentists
Children were asked who chose the MG they were wearing as part of their questionnaire (Figure 11). This was an open-ended question but answers broadly fell into one of three categories: the player themselves, one of their parents, and other (dental professionals, friends and other family members). Approximately the same proportion of MG were chosen by the players themselves (N = 55,
46.61%) and their parents (N = 51, 43.22%; Figure 11).
Figure 11 Distribution of who chose MG (%)
101 Parents were asked which type of MG their children wore as part of the parent questionnaire (Figure 12). Fifteen parents (12.71%) reported that their child was wearing a SMG (“shop bought, ready to wear”). Ninety-four parents (79.66%) reported that their child was wearing a MFMG (“shop bought, boil and bite”). Nine parents (7.63%) reported that their child was wearing a CMG (“made by dentist”).
Parent reports of MG type were then compared to the MG type observed by the dentist at the oral examination, for those participants who brought their MG with them (Figure 12; Table 3.16). Statistical comparison showed a low level of agreement between the MG type reported by parents and the actual MG type observed by the examining dentist (훋 = 0.47, p < .001). When children were wearing MFMG as determined by dentists, only three-quarters of parents (N =
64, 77.1%) correctly identified the MG type worn by their children. Twelve parents
(80.0%) correctly identified that their child was wearing a SMG. All parents of children wearing CMG correctly identified these MG, with one parent incorrectly identifying their child’s MFMG as a CMG. Three of the subjects whose parents reported they were wearing a CMG could not be verified as those children did not bring their MG for assessment. The results are presented in Figure 12 and Table
3.16.
102 4 9 Dentist-…
1 7
1 3
5 1 9 4
Stock Mouth-formed Custom
Figure 12 Identification of MG type worn by children: dentist and parent reports
(N)
Table 3.16 Parent report of mouthguard types worn by children compared to dentist identification of mouthguard type
Parent-reported MG type Total Stock Mouth- Custom N (%) 훘2 p N (%) formed N (%)
N (%) Stock N 12 19 (22.9) 0 (0.0) 31 Dentist- (%) (80.0) (30.1) reported Mouth- 3 (20.0) 64 (77.1) 1 (20.0) 68 MG type formed N (66.0) (%) 101.71 <.001* Custom N 0 (0.0) 0 (0.0) 4 (80.0) 4 (3.9) (%) Total 15 83 (100) 5 (100) 103 (100)
3.7.2 Quality of mouthguards: Mouthguard Fit
Mouthguards present on the day of data collection were assessed for characteristics relating to fit and thickness as a measure of their protective ability
(N = 106/121; 87.6% of the total sample). The results for this assessment are
103 presented as a proportion of those MG present and not as a proportion of the entire study population.
The characteristics of the MG worn in terms of MG fit are summarised in table
3.17 and graphically demonstrated in Figure 13. Of note, 86 MG (81.13%) were deemed to have inadequate intraoral retention and 89 MG (83.96%) had inadequate labial extension. Palatal extension was adequate in 64 MG (60.37%).
Approximately half of the MG had appropriate occlusal coverage (N = 57,
53.77%), satisfactory balanced occlusion (N = 47, 45.19) and an intact MG surface (N = 54, 50.94%). Deformation of MG shape was recorded for 47 MG
(44.34%).
Table 3.17 Frequencies of fit-related characteristics of MG
Adequate (N, %) Inadequate (N, %) Total
Retention 20 (18.87%) 86 (81.13%) 106
Labial extension 17 (17.04%) 89 (83.96%) 106
Palatal extension 64 (60.37%) 42 (39.62%) 106
Occlusal coverage 57 (53.77%) 49 (46.23%) 106
Balanced occlusiona 47 (45.19%) 57 (54.81%) 104
Border Smoothnessb 45 (46.88%) 51 (53.13%) 96
Mouthguard surface 54 (50.94%) 52 (49.06%) 106 a Balanced occlusion: missing data for 2 subjects, excluded from analysis. b Borders: missing data for 10 subjects. Excluded from analysis.
104
Figure 13 Chart showing proportion of MG with fit-related features which are inadequate (brown) vs. adequate (light blue)
A chi-square analysis was completed to investigate the influence, if any, of MG type on fit characteristics (table 3.18). The association between MG fit (as defined by MG retention) and MG type was significant (훘2 = 18.10, p < .001).
Cross-tabulation revealed that 87.1% of SMG and 83.1% of MFMG have inadequate retention, while 100% of CMG have adequate retention (table 3.18).
This needs to be interpreted with caution, however, given the fact that only 4 players brought CMG with them for assessment. No significant relationship was established for other variables relating to MG fit and type (table 3.18).
105 Table 3.18 Relationship between MG type and fit characteristics
Variable Mouthguard Type Mouth Total Stock MG Custom 훘2 p formed N N (%) N (%) N (%) (%) Retention
Inadequate 27 (87.1) 59 (83.1) 0 (0.0) 86 (81.1) 18.100 <.001*
Adequate 4 (12.9) 12 (16.9) 4 (100.0) 20 (18.9)
Labial extension
Inadequate 28 (90.3) 59 (55.7) 2 (50.0) 89 (84.0) 4.397 .111
Adequate 3 (9.7) 12 (16.9) 2 (50.0) 17 (16.0)
Palatal extension
Inadequate 15 (48.4) 27 (38.0) 0 (0.0) 42 (39.6) 3.696 .158
Adequate 16 (51.6) 44 (62.0) 4 (100.0) 64 (60.4)
Occlusal coverage
Inadequate 14 (45.2) 34 (47.9) 1 (25.0) 49 (46.2) 0.818 .664
Adequate 17 (54.8) 37 (52.1) 3 (75.0) 57 (53.8)
Balanced occlusiona
Inadequate 19 (63.3) 37 (64.9) 1 (25.0) 57 (54.8) 2.423 .298
Adequate 11 (36.7) 33 (47.1) 3 (75.0) 47 (45.2)
Border Smoothnessb
Inadequate 17 (58.6) 34 (53.1) 0 (0.0) 51 (53.1) 3.752 .153
Adequate 12 (41.4) 30 (46.9) 3 (100) 45 (46.9) a Balanced occlusion: missing data for 2 subjects. Excluded from analysis. b Borders: missing data for 10 subjects. Excluded from analysis.
The colour of the MG was also assessed and characterised as either transparent, light or dark. Half of the sample wore light-coloured MG (N = 52, 49.06%). Just over one third of the sample wore dark MG (N = 39, 36.79%), with the remainder wearing transparent MG (N = 15, 14.15%).
The colour of the MG may influence its fit (retention); a chi-square analysis was performed to investigate this relationship (Table 3.19). A significant difference
106 was observed between MG colour and inadequate retention (훘2 = 6.270, p =
0.044). A greater proportion of MG deemed to be light-coloured had inadequate retention compared to those MG deemed to be either dark in colour or transparent
(Table 3.19; Figure 14).
Table 3.19 Association between MG colour and MG retention.
Mouthguard colour Total 훘2 p Transparent Light Dark N(%) N(%) N(%) N(%)
Inadequate 9 (60.0) 46 31 86 (88.5) (36.0) (81.1) Retention Adequate 6 (40.0) 6 (11.5) 8 (20.5) 20 6.270 .044* (18.9)
Total (N) 15 (100) 52 39 106 (100) (100) (100)
Mouthguard Colour And Retention Inad…
6 8 6
46 31 9
Transparent Light Dark
Figure 14 Proportion of MG with adequate/inadequate retention, according to MG colour
3.7.3 Quality of mouthguards worn: mouthguard thickness
Average thickness measurements for each site on the MG are summarised in
Table 3.20 and Figure 15. Mouthguard thickness was measured as planned for all incisor, canine and molar sites on 105 MG; one MG did not extend past the
107 canines and so this subject’s MG has no values for thickness at the first permanent molars. This MG was excluded from analyses involving the first permanent molar site, but was included in all other analyses relating to thickness.
The value for MG thickness at each site was not normally distributed according to tests for normality (p < 0.001), and the range of values was wide for each measurement (Figure 15). The overall median labial thickness of the total MG sample was 4.08mm (IQR = 3.51mm – 4.53mm). The median thickness of the labial flange at the central incisors was 4.05mm (IQR = 3.51mm – 4.55mm). The median occlusal thickness posteriorly, measured at the first permanent molar site, was 3.9mm (IQR = 3.1mm – 6.4mm), and the median occlusal thickness anteriorly (combining the incisor and canine occlusal measurements) was
4.64mm (IQR = 2.98mm – 7.07mm).
The thickness values were compared to MG type to investigate the relationship between these variables using the Kruskall-Wallis H test (Table 3.21). For average labial thickness at the central incisors, there was a significant effect of
MG type, with MFMG having a significantly greater mean rank in thickness than both SMG and CMG (H = 20.409, p < .001; Table 3.21). There was also a significant effect of MG type on mean occlusal thickness posteriorly at the first permanent molars (Kruskal Wallis test, H = 6.553, p = .038). There was no association between average incisal edge thickness anteriorly and MG type (H =
3.91, p = .142; Table 3.21).
108 Table 3.20 Summary of MG thickness, per site (mean, median, standard deviation, interquartile range (IQR), and range)
Labial Labial Occlusal Occlusal Occlusal Average Thickness: Overall Thickness: Thickness: Anterior Occlusal Labial Thickness: Thickness: Occlusal Central Central Canines Thickness First Molars Canines Thickness Thickness Incisors Incisors (mm) (mm) (mm) (mm) (mm) (mm) (mm) (mm)
Mean 4.13 4.26 4.197 4.65 4.93 4.98 4.96 4.86
Median 3.98 4.05 4.08 3.90 4.33 4.53 4.64 4.38
Std. 1.12 1.18 1.12 1.96 2.15 2.37 2.18 2.04 Deviation
Interquartile 3.5 – 4.6 3.51 – 4.55 3.51 – 4.53 3.1 – 6.4 3.1 – 6.6 2.91 – 7.3 2.98 – 7.07 3.02 – 6.93 Range (IQR)
Range 7.55 6.40 6.98 8.30 9.55 8.25 8.35 7.20
Total (N) 106 106 106 105 106 106 106 106
109
Figure 15 Boxplot showing range of MG thicknesses at each site
Table 3.21 Association between MG type and thickness
Mouthguard type
Mean, SD (mm) Kruskal -Wallis p H Mean thickness Mouth- Stock Custom (mm) formed Central incisor, 3.67±0.65 4.58±1.26 3.18±0.43 20.41 < .001* labial
Central incisor, 4.08±2.64 5.18±2.27 2.86±0.62 3.91 .142 occlusal
First molar, 4.64±2.01 4.77±1.94 2.58±0.41 6.55 .038* occlusal
110
4 Chapter 4 Discussion
Prevention of sports-related dental injuries by wearing mouthguards (MG) is widely advocated among certain sporting organisations and among dentists worldwide. The protection afforded by MG will depend on many person- and MG- specific factors. This is the first observational study to investigate the type and quality of MG currently being worn by sports participants in a field setting. Studies investigating MG quality to date have either been laboratory-based or have investigated MG deterioration over time. It is also the first study to investigate the attitudes and behaviours in relation to MG use among parents and children playing a specific sport (Gaelic football) in Ireland. Previous studies (Evans and
O’Malley, 2018; O’Malley et al., 2012) investigated parent attitudes only via questionnaires distributed among primary schools (i.e. not specific to one sport) and did not include an examination component.
4.1 Study Setting
Investigating the quality of the MG actually being worn by sports participants is important as a means to inform future education of players, parents, coaches, and indeed dentists, on what constitutes a “properly fitting MG” in order to appropriately protect the dentition from injury. This is particularly important in a child and adolescent population, given the lifelong functional, aesthetic, economic and psychosocial implications of a dental injury to anterior permanent teeth at a young age.
The Gaelic Athletic Association (GAA), in particular Gaelic football, was selected as the setting for this study. Gaelic football is a very popular sport across Ireland among people of all ages, especially in Co. Dublin, where this study was carried 111
out. Therefore, it was anticipated that we would be able to access a sufficient sample to generate meaningful results for this study.
Gaelic football is governed by a central authority, the GAA, who introduced and implemented a mandatory MG rule in 2014 for players of all levels during Gaelic football training and matches. It was therefore anticipated that, depending on club enforcement, the majority of the sample would be adhering to these rules, and so would present a significant number of MG for quality assessment. Interestingly, the GAA rules only require for MG to be “properly fitted” per the player’s own judgement, and for the device to carry the CE mark (Gaelic Athletic Association,
2016). This study aimed to investigate whether or not the MG being worn were indeed fitting properly, and also whether they fulfilled the thickness criteria for adequate dentoalveolar protection as established in numerous laboratory-based studies.
The GAA reported a reduction in dental injury claims of 37% in minor (under age
18 years) player grades in 2016 following introduction of the MG rules (Gaelic
Athletic Association, 2016). It was reported by Evans and O’Malley (2018) that the Health Services Executive Public Dental Service had anecdotally experienced a reduction in sports-related dental injuries, though no evidence was provided to support this statement. This paper also reported that the incidence of sports-related dental injuries had reduced to 2.25% of their sample (Evans and
O’Malley, 2018) compared to 5.2% in the same authors’ previous study (O’Malley et al., 2012). The current study aimed to investigate whether this trauma experience was reflected in a sample conducted only among children playing
Gaelic football in clubs and not just at school.
112
4.2 Methods and Calibration
Examining teams attended Gaelic football training sessions on weekday evenings from 6pm-9pm, in different locations around Dublin city. Training and calibration of three examiners was required to accommodate the training session times. Inter- and intra-examiner reliability for qualitative assessments (i.e. identifying signs of trauma, assessing fit and retention of MG) were high (훋 > 0.8).
Inter-examiner reliability for quantitative MG thickness measurements was also high (> 85%).
Intra-examiner reliability for labial MG thickness measurements was also high for all 3 examiners (> 80%). Intra-examiner reliability for occlusal thickness measurements was less consistent, with two examiners scoring >79% and a third scoring only 47.5% for occlusal thickness measurements. This may be for a variety of reasons, including difficulty in accessing the occlusal surface and incisal edge with the calliper tips, and in choosing a correct measurement site, particularly for SMG as there are no occlusal landmarks on these MG. However, occlusal thickness was not an important outcome and results showed that it did not influence rates of wear in this sample. Ideally, a sample of MGs would have been repeatedly measured from each training session by all examiners to assess accuracy. This was not practical; it would have required either the players to play without their MG (in contravention of rules) or forego their training session.
4.3 Sample Size
As previously discussed, there is no other study in the literature which investigates both compliance with MG rules and the quality of the MG being worn by players; therefore, a power calculation and sample size estimation could not
113
be completed for this study. The aim was to examine as many children with their parents as possible, with a view to assessing 1-2 teams per club. This would equate to approximately 30 children per club.
Some challenges in accessing participants for this study were encountered.
Fourteen GAA clubs with Gaelic football teams were invited to participate. Eight clubs did not respond. Six clubs initially agreed to participate (projected sample
= 180 children). Four clubs engaged with arrangements to visit during training sessions and facilitated spaces for data collection during these times. Two clubs failed to engage with subsequent attempts to contact them to arrange visits; these were therefore excluded. As a result, the total sample size was smaller than anticipated at the outset of data collection (N = 121 children).
Data collection was carried out at Gaelic football training sessions, as clubs did not want any disruptions on match days. Parents of the players tended to drop their children off for training and did not usually stay to observe training sessions.
This compromised the ability of the research team to recruit participants.
Participation also varied among clubs. All clubs sent an email one week before the appointed club visit, notifying parents of the study along with the participant information leaflets. However, some clubs also shared reminders to parents via team WhatsApp groups in the days leading up to data collection, while other clubs did not. This is reflected in the different numbers of participants in some clubs compared to others.
Due to unforeseen delays with ethical approval and permission from the GAA and
LGFA, and challenges with the calibration exercise, data collection took place during the Autumn-Winter 2019 training season, which presented some
114
unexpected challenges. On several occasions, the research team attended the club at agreed training times, but training had been cancelled due to adverse weather conditions.
4.4 Questionnaires
There is no validated questionnaire available to assess knowledge and behaviours of parents or sports participants (in this case, children) in relation to the use of MG in sport. The parental questionnaires used in this study were formulated based on the questions published by O’Malley et al. (2012); this study was selected as the only Irish questionnaire-based study at the time of research protocol development. The same questions were used, with the addition of questions seeking information in relation to the cost parents would pay for a CMG; compliance with GAA MG rules for training and/or matches; and MG age, storage and hygiene. Unlike O’Malley et al. (2012), these questionnaires were completed by parents at the time of their child’s clinical examination.
The parent questionnaire did not ask about the gender of the parent responding
(i.e., whether it was the mother or the father), nor did it seek any information on family socioeconomic status or parent educational level. This would have been valuable to compare the responses regarding parent knowledge of MG use with studies from other countries which did seek this information (Hegde et al., 2010;
Quaranta et al., 2016; Yassen et al., 2013). It would also have been interesting to investigate if there was an association between socioeconomic background and/or parent educational level, and the type and quality of MG being worn by the players. This is something that could be included in future studies, perhaps using medical card status as a proxy for socioeconomic status in Ireland.
115
During development of the parent questionnaire, it was piloted among parents of children attending the paediatric dental clinics at the Dublin Dental University
Hospital. The purpose of this pilot was to ensure that the questionnaire was understandable both for native and non-native English speakers, and not for the purposes of statistical analysis. Parents were asked to comment if something was not clear. Minor amendments were made to the questionnaires taking all feedback into account and the parent questionnaire was then finalised.
The questions used in the child questionnaires were based on the final parent questionnaire, but the language was amended to make it easier for the questions to be asked and for children of this age group to understand. The resulting questionnaires were not always directly comparable in terms of how the questions were asked; this became evident during data analysis for compliance with MG rules. This has highlighted the need for developing and validating standardised questionnaires for future investigations of this nature.
The dentist examination sheet was formulated based on the criteria for the “ideal”
MG as outlined in Table 1.7 (Chapter 1). Additional questions relating to child age, gender, presence of signs of previous trauma and overjet were also included.
4.5 Characteristics of the sample
A total of 121 children were examined; 117 parents completed the parent questionnaire, and all but 1 child questionnaire was completed. A number of players presented to the examiners’ team for assessment but they had not been brought to training by their parents, and so they could not participate in the study without valid parental consent. This occurred at each club visit.
116
Child ages ranged from 9-16 years old. This age group was selected as it was felt that children aged 9 would most likely have all permanent maxillary central and lateral incisors erupted into the mouth by that age. Additionally, children aged
9 and over would have a greater ability to comprehend the questionnaire and may provide more reliable answers than younger children. An upper age limit of
16 years was selected so that parent participation was encouraged, and correlation of parent-child data could be performed. The data was not normally distributed; there were greater numbers of children aged 9, 13 and 15 in particular, but children of all ages were examined. Within this sample, just over half were male (N = 68, 56.67%) and just under half were female (N = 52,
43.33%); this distribution is similar to that reported by both O’Malley et al. (2012) and Evans and O’Malley (2018).
4.6 Self-reported trauma experience
Parents and children were asked if they recalled an episode of trauma to the child’s permanent teeth - if they had “ever” suffered trauma to their permanent teeth, to gain an indication of the prevalence of TDI and specifically SRDI. This was an imprecise measure as it was reliant on parent and child recall, which may have resulted in memory bias.
Previous questionnaire-based studies conducted in Ireland asked about trauma experienced within the previous year only (Evans and O’Malley, 2018; O’Malley et al., 2012). These studies were also carried out in a sample of parents recruited through the school their child(ren) attended. They also did not include any clinical examination of the child(ren) concerned. Therefore, while they are a useful
117
indicator of the situation in Ireland, the results may not be directly comparable to the current study.
The proportion of children reporting a previous TDI (17.5%) in this study is similar to the global prevalence of TDI in the permanent dentition of children and adolescents, which is 15.2% according to Petti et al. (2018). This is greater than both parent- (6.84%) and dentist-reported prevalence (12.4%). Ten per cent of children and 2.6% of parents reported that the past dental injuries were sports related. Stewart et al. (2011) reported that 23.3% of dental injuries observed in their Irish sample were sports-related. However, that study may be biased. It was an audit of a specialist dental service, data was retrospective, only 1 year was examined, and the sample size (94 children aged 5-17 years) was smaller than the current study (Stewart et al., 2011). Therefore, the results are not directly comparable.
Child-reported rates of SRDI in this study (9.9%) are greater than parent-reported prevalence reported by both O’Malley et al., (2012) and Evans and O’Malley
(2018), who reported SRDI rates of 5.2% and 2.25% respectively. These results are not comparable, however, because these studies surveyed parents only.
There is no Irish data on child-reported prevalence for comparison.
Galic et al., (2018) surveyed young sportspeople aged 5-19 years among 4 sports
(water polo, taekwondo, karate and handball) and overall, 13.5% of their participants reported SRDI in the past. The age range was wider than the current study and it was not specified whether the permanent or primary teeth were in question, which may explain the greater prevalence (Galic et al., 2018). The current study investigated trauma experience to the permanent dentition only.
118
Qudeimat et al., (2019) reported a prevalence of SRDI of 11% among 7-18-year- olds playing soccer in Kuwait, comparable to the current study.
Parent-reported rates of SRDI (2.6%) are lower than those reported by parents surveyed by O’Malley et al., (2012) and comparable to Evans and O’Malley
(2018). This raises an interesting point whereby parent and child report may not be equivalent. Parents may only recall more severe injuries warranting dental attendance. This was not investigated in the current study and would be valuable to ascertain in future research.
4.7 Observed signs of traumatic dental injuries
Signs of TDI were observed by dentists in 12.4% of the sample (N = 15 children).
One of these children did not complete the questionnaire so there were only 14 subjects available for statistical comparison. This is slightly less than the global prevalence of 15.2% as reported by Petti et al. (2018).
While the frequency of signs of TDI was similar to the player-reported prevalence of 9.9%, 8 children who displayed signs of trauma had denied a past history of injury (57.1% of those with signs of trauma; 6.67% of the total sample). This is also shown by the fact that agreement between child-reported past TDI and dentist-observed signs of TDI was low, at only 23.6% (훋 = 0.236, p = .008).
Two-thirds (66.67%) of observed injuries were enamel-only fractures (Andreasen classification of dental injuries as published by Andersson et al. (2019)). This is comparable to Qudeimat et al., (2019), who reported that enamel-only fractures were observed in 60% of their population, using the same classification
(Andersson et al., 2019). A cross-sectional study carried out in India reported
119
enamel-only fractures in 68.45% of the 12-year-olds examined, using the Ellis and Davey criteria (Ain et al., 2016).
Signs of TDI are not a reliable indicator of total trauma experience; not all TDI result in visible changes to the tooth unless there has been a fracture, colour change, or change in position of the teeth. Additionally, it is impossible to tell when and how TDI occurred from clinical signs alone. Therefore, it is possible that this study underestimates the prevalence of TDI in general, and specifically
SRDI, in the sample. A reduction in rates of TDI cannot be ascertained from this study due to the absence of a reliable baseline measure of TDI prevalence in this population prior to the introduction of the MG rules.
4.8 Incisal Overjet and Trauma
It is well documented in the literature than an increased overjet is associated with greater risk of TDI (Årtun et al., 2005; Brin et al., 2000; Burden, 1995; Silva-
Oliveira et al., 2018). In this study, just under half of the sample (44.6%) had an increased overjet (> 3mm) as estimated by the clinical examination. Ten of the children with signs of TDI (10/15 children, 66.67%) had an increased overjet.
Statistical tests for the significance of this association were inconclusive due to the small number of subjects. A significant association between increased overjet and TDI prevalence was reported by the most recent epidemiological survey of oral health in Irish children and adolescents (Whelton et al., 2006).
4.9 Sports Participation
The population in this study were very active, with 93.6% playing more than one sport and almost two-thirds playing 2-3 sports. This is similar to the level of sports
120
participation reported by O’Malley et al., (2012). Participants in the current study played a mean of 3.07 ± 1.37 sports, and a mean of 2.43 ± 0.81 contact sports.
The setting of this study may have influenced the types of sports that the participants play. The entire sample played Gaelic football (as this was an inclusion criterion); 66.94% of the sample also played hurling or camogie which is unsurprising as these sports are also under the auspices of the GAA, and Co.
Dublin has eminent Gaelic football and hurling/camogie traditions. This was a different proportion to that reported by O’Malley et al., (2012), where 65% played
Gaelic football and 39% played hurling or camogie. Their sample was recruited from a range of primary schools in numerous counties on the West of Ireland.
Soccer was played by 23.97% of children; this was more popular among the population examined by O’Malley et al., (2012) where 62% of the sample reportedly played soccer. Fewer participants in the current study reported playing rugby (6.61%) and basketball (19.00%) compared to 27% and 40% respectively
(O’Malley et al., 2012). Hockey was popular in the current study, with almost a quarter of children reporting playing hockey (22.31%); this sport was not reported on in 2012. These differences may have been influenced by different settings and timings of the two studies, and by the location of the participating GAA clubs.
4.10 Mouthguard rules and use in sports besides Gaelic football
In Ireland, the only sports with organisation-mandated rules for MG wear are the
GAA and boxing. In hockey, MG are recommended but not mandated (The
International Hockey Federation, 2018). Local hockey clubs may have their own rules where a MG is required to participate; 85.19% of parents and 96.3% of children in this study reported that their hockey clubs had MG rules. Despite this,
121
the rate of MG wear among hockey players in this study was only 77.78%. This is a similar pattern of wear to that reported in a study of Dutch field hockey players
(Vucic et al., 2016b), where 77% of field hockey players wore their MG for both training and matches. A systematic review of field hockey players by the same author reported the rate of MG wear was 57.9% overall, with greater rates reported in studies conducted after the year 2000 (84.5%) compared to those published before 2000 (31.4%) (Vucic et al., 2016a).
The situation for rugby in Ireland is similar to hockey; MG are encouraged, but not required, yet local clubs may have their own MG rules and policies. All but one parent (N=7, 87.5%) and child (N=7, 87.5%) reported that they were required to wear MG for rugby. The rate of wear among rugby players was 87.5% (7/8 players); thus, overall, the level of knowledge of the need for MG was high among rugby players and the corresponding rate of wear was high. As this was a very small proportion of the study population, the results cannot be generalised to rugby as a sport in Ireland, and research specific to MG use in rugby in Ireland is warranted.
Boxing and martial arts were not popular among participants in this study (5 children, 4.13% of the total sample). Knowledge of the rules for MG in boxing and martial arts was low among parents of these children, with only 3 parents reporting that these sports require MG. Only 2 children reported that there were rules for MG wear in boxing/martial arts; these were the only children who were wearing MG for these sports. This is a low level of knowledge and compliance, especially given the fact that boxing was the first sport to introduce the use of MG for dentoalveolar protection (Sigurdsson, 2013). The number of subjects participating in these sports is low in the current study, however, so these results 122
cannot be generalised to boxing and martial arts in Ireland as a whole. This is a potential area of future research given the increased popularity of mixed martial arts in this country in recent years.
4.11 GAA Mouthguard Rules: Awareness and Compliance
The parent questionnaire asked, in one single question, if their children wore their
MG for Gaelic football training only, for training and matches, or for matches only.
Children were asked if they wore their MG for training and for matches as two separate questions. This is a flaw in the design of the questionnaires which has precluded direct statistical comparison of the responses.
All parents responded that their child wore their MG either for matches only
(partial compliance with GAA MG rules – 10%) or for training and matches (full compliance with GAA MG rules – 89.7%). The rates observed in the current study are comparable to those observed by Evans and O’Malley (2018), where 87% of the population was wearing MG for Gaelic football. The enforcement of the MG rules for GAA has increased the use of MG from a 2012 baseline of 22%
(O’Malley et al., 2012).
Child-reported compliance with GAA MG rules for Gaelic football matches was excellent (N = 119; 99.17%). Ninety-seven players (80.83%) reported that they were wearing their MG during Gaelic football training – a reduction in compliance of 18.37%, compared to wear during matches. The discrepancy in compliance between training and competition events is well-documented in the literature.
Kroon et al. (2016) carried out a questionnaire study among 8-15-year-old rugby players in Australia. Player-reported compliance for matches only in their study was 49.75% and for training and matches was 21.53%, a reduction of 28.22%
123
(Kroon et al., 2016). Ilia et al. (2014) reported that 57.2% of players wore MG for competition only, and 41.6% wore them for training and competition (a reduction of 15.6%). The results in this study (i.e. 18.37% reduction in compliance between matches and training) is similar to that reported within the literature.
The reasons for the reduction in compliance during training as compared to matches in this study may be due to a variety of reasons. Enforcement of the
GAA MG rules lies with referees during matches, with the penalty supposedly being sent off from the play if the referee detects a lack of MG – “No Mouthguard?
No Game!” (Gaelic Athletic Association, 2016). The guidance from the GAA states that referees are not expected to check that each player is wearing a MG before a game begins, but only to send a player off if absence of a MG is noted in the course of play, and the player refuses to wear a MG (Gaelic Athletic
Association, 2016). There is currently no data available on enforcement of these rules at matches.
In the case of MG rule enforcement during training sessions, the GAA guidance states that it is the responsibility of the individual player (parent if the player is a minor, as in the case of this study) to ensure that they wear a MG on these occasions, and they themselves are liable in the event of a TDI should they fail to wear a MG (Gaelic Athletic Association, 2016). Players are not covered under the GAA Player Injury Scheme in the event of an injury if they were not wearing a MG at the time of injury (Gaelic Athletic Association, 2016). The role of the GAA club is to “ensure that their players, player’s parents/guardians, coaches and team mentors are made aware of the mouthguard rules” (Gaelic Athletic
Association, 2016). Therefore, it follows that players may not have the necessary intrinsic motivation during training to wear their MG if there is no external 124
enforcement of the rules or penalty for non-wear. There is currently no data on the knowledge and attitudes of mentors in Gaelic football in relation to the use of
MG; this would be an interesting future avenue of research.
Legislation is only one factor that might influence compliance with a MG rule.
Binary logistic regression analysis was used to investigate the influence of variables (child age, gender, previous history of dental trauma, number of sports played, number of sports where MG is worn, ability to speak and breathe while wearing MG, taste associated with MG, whether they like or dislike their MG, whether or not they chose the MG themselves, MG age, MG type, labial and palatal MG extension, MG retention, balanced occlusion, and labial and occlusal
MG thickness) on the level of player compliance with MG rules during Gaelic football training. A similar analysis was not completed for Gaelic football matches since all but 1 player reported that they were compliant with rules during competition.
Age was associated with child compliance, with older children less likely to comply with MG rules during training. In the univariate analysis, compliance reduced by 77% for each additional year of age. This was the only association maintained in the multivariate (adjusted) analysis, with the final result being that compliance with MG rules during training reduced by 82% for each additional increase in age by 1 year.
This finding is contrary to much of the published evidence relating to age and MG wear in general. Several studies have reported that younger children are less likely to wear MG compared to older children. Zamora-Olave et al. (2018) reported that, among water polo players, under-10 and under-12 age groups
125
were significantly less likely to wear MG than under-18 and senior teams. Greater compliance with MG use during rugby was also observed for older than for younger children by Kroon et al. (2016). Athletes under 22 years of age were reportedly 3.5 times less likely to wear MG compared to those aged 22 or over in a study by Boffano et al. (2012). However, non-compliance with MG rules during training in older participants may relate to intrinsic personality traits and adolescent behaviours. Collins et al. (2015) investigated the role of impulsivity in
MG wear among adolescents and concluded that those who were more impulsive were less likely to comply with MG rules. Their recommendations were that specific MG rules and penalties for non-adherence were the only way to ensure adolescent compliance with MG rules (Collins et al., 2015).
In the univariate analysis, there was a significant association between whether or not the child felt able to speak and breathe properly while wearing their MG, and whether they liked or disliked the MG. Each of these factors individually (i.e. ability to speak, ability to breathe, and like/dislike MG) were associated with compliance with GAA MG rules in the univariate binary logistic regression analysis. The likelihood of wearing a MG during training was 3.81 times greater for children who felt they could speak with the MG in place; it was 5.11 times greater for children who could breathe while wearing the MG; and was 3.95 times greater for children who stated that they liked their MG. These associations were lost in the adjusted model. It is possible that significance may have been retained in a larger sample.
Females were 11 times more likely to comply with MG rule during training compared to males in the univariate analysis. This association was not maintained in the multivariate (adjusted) analysis, though this association may have been maintained if the sample size had been larger or if fewer variables had 126
been included in the adjusted analysis. The evidence in the literature with regard to gender and compliance with MG use in general is conflicting. A systematic review and meta-analysis of MG use among field hockey players concluded that females were more likely to wear MG than males at both elite (OR = 5.5, 95% CI
3.3-9.3) and non-elite (OR = 1.7, 95% CI 1.1-2.5) levels (Vucic et al., 2016a). A cross sectional study in a Dutch field hockey population noted a slightly greater level of MG wear among males (19%) than females (15%) but this was not significant (Vucic et al., 2016b). Other studies have reported significantly greater compliance with MG wear has been reported among males than females
(Matalon et al., 2008; Rodd and Chesham, 1997).
An association between number of sports played and wearing MG during Gaelic football training was noted in the univariate analysis, with players being 1.85 times more likely to wear MG during training for every additional sport they played. However, this association was not maintained in the multivariate analysis, and there was no association between the number of sports for which they wore a MG and compliance with MG rules during training.
In the univariate analysis, MG compliance was associated with palatal extension, with those children with a MG with an adequate palatal extension being less likely to wear MG during training than those with an inadequate palatal extension (OR
= 0.12). It is difficult to say why this was the case; there is no evidence in the literature to support or refute this. This relationship was not preserved in the multivariate analysis.
An association between posterior occlusal MG thickness (as measured at the first permanent molars) and MG wear during Gaelic football training; children were
127
1.53 times more likely to wear their MG for every additional 1mm in thickness at this site. As for palatal extension, this association was lost in the multivariate analysis.
It is important to note that the low power (small sample size) of this study requires caution in interpreting the results of this multiple logistic regression analysis.
Though a significant association between age and MG use during Gaelic football training was established in this study, this finding must be interpreted with some caution given the relatively small sample size. It is therefore possible that other variables may significantly influence compliance during training, but this significance may have been lost due to the low power of this study.
4.12 Child/Player Attitudes to the Use of Mouthguards in Sport
As part of both child and parent questionnaires, a question was posed as to whether the player wears their MG for “some or all” sports that they participate in. There was a significant difference between the parent and child answers, with more parents (69.5%) than children (14%) reporting that MG are worn for all sports, and a low-level agreement between parents and children (훋 = 0.271, p =
.001). It has been reported that MG are often worn only for sports that have rules and not for others, despite the potential risk of SRDI associated with sports without MG rules (Collins et al., 2016).
Children who only wore their MG for some sports were asked an open-ended question as to why they did not wear their MG for all sports. The main reason given for non-wear of MG for other sports besides Gaelic football was that MG were not required by those sports (52.88%). In the literature, not wearing a MG because it is not necessary or not required has been reported by many other
128
studies. A study among high school athletes (adolescents) reported that a slightly greater proportion (65.3%) of their sample did not wear their MG for this reason
(Collins et al., 2015). Over one-third (37%) of young athletes who reported not wearing their MG in the study by Galic et al. (2018) stated that it was because they felt MG were unnecessary.
One third of those who reported not wearing MG for other sports reported that it was because they played hurling or camogie, and wore a helmet with a faceguard for these sports (N = 35; 33.65%). Hurling and camogie are high-speed, high impact contact sports involving the use of a wooden hurl (stick) and a hard ball
(sliotar). These sports are also regulated by the GAA. There is currently no evidence available as to the rates of SRDI associated with hurling or camogie, the rates of compliance with helmet/faceguard rules, and whether this equipment is sufficiently protective against SRDI.
Only 1 participant noted that they could not wear their MG at any time due to discomfort, in contrast to the majority of the literature relating to reasons for non- wear. Discomfort has been reported as a prominent reason for non-wear of MG in several studies. Razzak et al. (2019) reported that 38% of their study population did not wear MG because of “dislike of feeling” of wearing MG. Braham et al. (2004) reported discomfort as a reason for non-use of MG in 45.8% of their sample. One quarter of athletes surveyed by Bergman et al. (2017) reported that they did not regularly wear a MG because of appliance discomfort.
Issues with speaking with the MG in place is another common reason for not wearing MG. Forty-seven children (39.17%) reported problems with speaking when they had their MG in place. This is comparable to Lee et al. (2013), where
129
speaking problems were also reported as a reason for non-wear by 38.2% of the sample. For team sports, speech is an important parameter as communication between players is necessary during both training and competition.
Breathing problems were reported as a reason for not wearing MG in several studies, with variability in the magnitude of the effect of these issues on MG wear between studies. Only 10 children (8.3% of the current sample) reported issues with breathing, which is much lower than many reports in the literature (Boffano et al., 2012; Lee et al., 2013), but comparable to Galic et al. (2018). This may be because the current sample is recruited from a child/adolescent population and most other studies include older participants.
Six children (5.76%) reported that the sports for which they did not wear a MG were not contact sports and so a MG was not required. Two of these children were basketball players, which involves a high degree of contact. Twenty-four per cent of the total sample reported playing soccer, which is a contact sport; only
3 of these children reported wearing a MG for soccer and the remainder stated that they did not wear MG because it was not needed.
Children in this study generally had positive attitudes towards the use of MG, with the majority of the children surveyed stating that they liked their MG (N = 87,
72.5%). Children were not specifically asked in the questionnaire whether their
MG was comfortable or not. It is possible that, because the questions were posed to them by a dentist, they may have felt they should answer in such a way as to please the investigator. On a practical level, data collection took place with all examining teams in one room; children may have been influenced by answers they overheard from their team-mates. It would be interesting to examine whether
130
a similar sample would respond as positively to a self-administered questionnaire.
4.13 Parent Knowledge and Attitudes to the Use of Mouthguards
in Sports
In the parent questionnaire, participants were asked to indicate which type(s) of
MG they believed would best protect their child’s teeth. Almost three-quarters of parents in this sample indicated that a CMG would best protect their child’s teeth.
This reflects an apparently greater understanding of the role of a CMG among
Irish parents in this population, compared to the parents surveyed by Evans and
O’Malley (2018) where only 40% of parents believed a CMG was safer than other types.
In this sample, though 87 parents (74.36%) believed a CMG was the best for protection from dental injury, only 4 children (3.8%) were actually wearing a CMG.
This trend was also noted by Evans and O’Malley (2018), where only 4% of their sample reported that their child was wearing a CMG. This reflects a dissonance between what parents believe is best and what the situation is in reality. Parents’ responses to this question may have been influenced by the knowledge that a dentist was posing the question; they may have responded as they believed they should, as opposed to sharing their true opinion. The reasons for this dissonance among parents in terms of the type of MG they purchase for their children in terms of their beliefs of which is best is an area with potential for future investigation.
Several surveys of parents have identified cost as a barrier to the provision of
MG. Matalon et al. (2008) reported that 20.8% of the children in their population had not had a MG before the study due to the associated expense. Cost of MG
131
was also a reason for children not wearing MG in the study by O’Malley et al.
(2012).
The parent questionnaire in this study asked parents to indicate how much they would be willing to pay for a CMG for their child. There was a wide range in responses, from €10.00 all the way up to a maximum of €100.00. The median cost indicated was €35.00 (IQR = €20.00-€50.00). This corresponds to approximately US$41.15 (October 2020 exchange rates).
Walker et al. (2002) reported that parents were willing to pay a maximum of
US$25.00 for a CMG, with the majority of their sample unwilling to pay that much.
Adjusting for inflation, this translates to US$36.19 in 2020 (U.S. Bureau of Labor
Statistics, 2020). However, the studies are not directly comparable. The question in relation to cost posed by Walker et al. (2002) asked parents if they would pay
$25.00 for a CMG, whereas the current study aimed to establish the value parents placed on a CMG as an appliance. The children in the Walker et al. (2002) study were also younger than the children included in this study.
Khodaee et al. (2011) reported that parents were willing to pay an average of
US$50.00 for “safety equipment” for their children playing soccer. This is slightly higher than the amount parents in the current study were willing to pay for a CMG.
However, support for the mandatory use of MG was low, at only 53.8%, and only
55.5% would encourage their child to wear MG if provided free of charge
(Khodaee et al., 2011). Parents in the current study supported the use of MG, with 100% of respondents stating that their child had and wore a MG.
The cost differential between MG types could influence the type of MG worn by the child. From the linear regression analysis, whether the children wore their MG
132
for some or all sports was a very weak predictor of the price parents would pay for a CMG.
The price parents in this study were willing to pay for a CMG must be interpreted in the context of the additional costs associated with a child playing Gaelic football. Individual juvenile membership subscriptions for the clubs in question ranged from €20.00 for one club to €100.00 – €132.00 for the remaining 3 clubs.
Some clubs have a discount if there are multiple members from the same family.
Parents must also purchase the club kit for their child (including jersey, shorts, socks, gloves); the average total cost for these items is €75.50 per child
(https://www.thegaastore.com). Football boots must also be purchased; these range in price (at full price) from €25.00-€160.00 (https://www.elverys.ie). If a family has multiple children playing multiple sports, it is understandable that they may choose to opt to for a cheaper MG option than a CMG. Stock MG and MFMG are readily available in sports stores around the country. The average price of a
SMG is €5.00 (https://www.thegaastore.com, https://www.elverys.ie). Mouth- formed MG range in price from €8.00 to €40.00, depending on the brand and the size (https://www.thegaastore.com, https://www.elverys.ie). In private practice in
Ireland, the fee for a CMG is on average €70.00-€150.00 (personal communication, June 2020). The findings of the current study show that parents are willing to pay less than the average fee for a CMG for their child. This is interesting when contrasted with the cost of treating a dental injury, particularly in the light of recent Irish data from a university dental hospital where the cost of treating a complex injury in the first year alone was €1613.30 (Bani‐Hani et al.,
2020). There is a need for further education of players and their parents around the consequences of dental trauma, both in terms of psychosocial ramifications
133
of aesthetic and functional compromise, and in terms of the long-term cost. It is clear that the long-term cost of a dental injury far outweighs the short-term annual cost of a new CMG.
4.14 Mouthguard Care and Hygiene
Mouthguards are like any other removable dental device; they are a foreign surface and can be colonised with a wide range of micro-organisms through use, particularly if not appropriately cared for through proper cleaning, disinfection and storage (D’Ercole et al., 2020; Glass et al., 2011; Ogawa et al., 2012). Children and their parents were surveyed in this study to establish their knowledge and behaviours in relation to care of the MG being worn.
4.14.1 Mouthguard Storage
The majority of both parents (N = 77, 65.25%) and children (N = 85, 70.83%) reported that MG were kept in a designated box when not in use. Twenty-seven parents (22.88%) and 21 children (17.5%) reported that MG were kept loose in their gear bag with the remainder of their football kit. Smaller proportions of parents (N = 14, 11.9%) and children (N = 14, 11.67%) reported that MG were kept in “other” locations – gloves, socks, on radiators, in bathroom cabinets and on bedside lockers. Parent and child responses in relation to where the MG was kept when not in use were only in agreement 56.3% of the time.
There were no studies in the literature reporting on existing MG storage behaviours of players and/or their parents. Some individual MFMG companies supply care instructions with the forming instructions, both in the packaging and online, normally recommending for MG to be cleaned using water (ShockDoctor
(https://www.shockdoctor.com) recommend hot water and soap; O’Neills
134
(https://www.oneills.com) recommend cold water). It is unclear what information, if any, is provided by dental laboratories and individual dentists on care and maintenance of MG. The GAA provides storage and hygiene advice in their “GAA
Mouthguard Information” pamphlet (Gaelic Athletic Association, 2016), but it is unclear as to whether this information is given to players or whether it must be sought out. Their recommendation is for MG to be stored in a perforated container, away from high temperatures. These recommendations are supported by the results of in vitro studies regarding microbial contamination of MG (Cortelli et al., 2014; D’Ercole et al., 2020; Ogawa et al., 2012).
4.14.2 Mouthguard Hygiene
Like any dental device, a MG should be cleaned frequently, ideally after each use. The proportion of both parents and children reporting that MG were
“rarely/never” cleaned was notable (39.8% of parents; 45.8% of children); agreement between parent-child responses was low (41.4%). The only other study reporting on existing MG cleaning behaviours (Namba et al., 2013) reported that only 1 out of their sample of 22 players (4.54%) surveyed was regularly cleaning their MG, and a further 7 players (31.82%) reported “sometimes” cleaning their MG. The population in this study reported improved frequency of
MG cleaning compared to the Namba et al. (2013) study.
Parents and children were also asked how the MG were cleaned. Evidence in the literature with regard to how best to clean MG is scarce; water will not decontaminate the device, but using other agents such as toothpaste, sodium hypochlorite or hydrogen peroxide may abrade the EVA and facilitate microbial attachment (D’Ercole et al., 2020). The majority of respondents in this study
(61.2% of parents, 79.3% of children) stated that MG were cleaned using cold 135
water. Almost one quarter (23.3%) of parents and 12.2% of children reported using warm water to clean their MG. Agreement between parents and their children for this question was poor (훋 = 0.258). Cold water was also the preferred cleaning method in the Namba et al. (2013) study. No other studies in the literature investigating the existing player habits for cleaning MG were found during the literature search.
From the results of this study it is clear that players and their parents are unaware of how and when to clean MG. Education of all involved with sports is needed in this regard, as to wear contaminated oral devices raises the risk of microbial infections which may compromise oral and general health (Namba et al., 2013).
Dental professionals have a crucial role to play in promoting appropriate care and maintenance of MG to maximise player wellbeing.
4.14.3 Mouthguard Age
Seventy-seven parents (65.25%) and 69 children (57.5%) reported that the player’s MG was 6 months old or less. While there has been no observational study of the age of MG worn by sports participants, and there is no consensus on frequency of changing MG in the literature, it has been shown that MG deform over time. Del Rossi et al. (2007) carried out a small study among 11 high school football players, where each player was provided with a CMG at the beginning of the season. The overall shape of the MG changed over the course of the 12- week season (Del Rossi et al., 2007).
Dimensional changes are likely due to the fact that MG undergo repeat cycles of heating and cooling, as well as repeated wetting and drying (Gould et al., 2009a,
2009b). Players may also have a habit of biting or chewing on MG which may
136
accelerate or accentuate deformation (Del Rossi et al., 2007). Mouthguard deformation was noted in almost half of the MG assessed in this sample
(Appendix 13.6). Glass et al. (2009) recommend that MG should be replaced once there is any deterioration of the surface including sharpness of edges and distortion of the form of the device.
4.15 Mouthguard Quality Assessment
4.15.1 Types of Mouthguards Worn by Children in this Sample
In the current study, the majority (80%) of parents reported that their child was wearing a MFMG. This reflects trends in previous Irish studies that MFMG are the most popular type of MG among young sports participants in Ireland (Evans and O’Malley, 2018; O’Malley et al., 2012).
Similar proportions of parents (4%) in the current study reported that their child was wearing a CMG as parents in the population of O’Malley et al. (2012) – 4%
– and greater than the proportion reported by Evans and O’Malley (2018) – 2%.
It must be noted, however, that the Evans and O’Malley paper did not report on the responses of the whole sample regarding this question. Therefore, this requires caution with interpretation, though it is included here as a paper in the
Irish context.
As part of the dentist examination, 71 of the children in this study (66.98%) were wearing MFMG. Almost one third (N = 31, 29.25%) were identified as SMG, with only 4 CMG identified (3.8%). There were no other studies in the literature where a dentist examined the existing types of MG being worn by sportspeople; existing evidence on types of MG being worn comes from questionnaire-based studies of players and of parents.
137
One third of parents surveyed by Khodaee et al. (2011) stated that children were wearing SMG, 4% were wearing CMG, but the authors did not account for the remaining 63.4% of the sample or report on the proportion wearing MFMG. It is possible that the remaining 63.4% were wearing MFMG, which would mean the profile of MG types used would be broadly similar to the current sample; however, this assumption cannot be made from the published data (Khodaee et al., 2011).
Agreement between parent-reported and dentist-identified MG types was poor in this study. This may have been because almost 13% of children in the study did not bring their MG for assessment, so verification of parent reports was not feasible. Equally, parents may not know which type of MG their child wears. In the study by O’Malley et al. (2012), 19% of the parents surveyed stated they did not know which type of MG their child wore. Some responses in the current study may have been guesses because there was no option to indicate “don’t know” in response to the question relating to MG type on the parent questionnaire.
Kroon et al. (2016) included this question in their survey of junior rugby players in Australia. The majority of their sample also reported wearing MFMG (64.7%), though unlike the current sample, the next most popular MG type was the CMG
(23.1%) (Kroon et al., 2016). There was a trend for greater use of CMG with increasing age (Kroon et al., 2016); this could not be examined in the current study due to the small number of participants using CMG. Additionally, children in this study were not asked which type of MG they were wearing, which is a limitation and should be included in any future studies.
138
4.15.2 Quality of Mouthguards Worn in a Sample of Children Playing
Sport in Ireland: Mouthguard Fit
The fit of MG in this study was judged based on the retention, extension and occlusion on the MG assessed. This study is novel in that it is the only known investigation of the quality of fit of the MG worn by children playing sport, as selected by/for those children, not provided by a research team. Photographs of a selection of MG assessed in this study are included in Appendix 13 (1-7).
4.15.2.1 Mouthguard Retention
In the literature, it is reported that a MG must be properly fitted and retained to appropriately protect the wearer from dentoalveolar trauma (Ferreira et al., 2019;
Scott et al., 1994). Over 80% of the MG assessed in this study had inadequate retention as judged by clinical assessment (Appendix 13.1, 13.4, 13.6, 13.7).
There was a significant effect for MG type and retention.
The accuracy of fit of the MG material around the individual teeth on its fitting surface influences MG retention. For SMG, given the design and lack of capacity to make any adjustments, it follows that they would naturally have poor retention as they are not moulded around individual teeth in any way (Gawlak et al., 2014;
Scott et al., 1994; Sigurdsson, 2013). This has been reflected in the findings of this study, with 83% of SMG having inadequate retention.
During the fitting of MFMG, there is a delicate balance to be struck between having the core temperature high enough for adequate moulding, without causing burns to the soft tissues of the oral cavity (Guérard et al., 2014). It has been reported that this is difficult if not impossible to achieve, likely to result in poor MG fit (Guérard et al., 2017, 2014; Hoffmann et al., 1999; Patrick et al., 2005). Proper
139
fit of a MFMG depends on the ability of the parent and child to appropriately perform the moulding procedure. The findings of this study suggest that this is not the case, as 87% of MFMG had inadequate retention. Though not directly comparable, this is in agreement with the laboratory study by Guérard et al.
(2017), who found that retention of two of the three MFMG included in their sample had insufficient retention compared to the other MFMG and two CMG.
Where it is necessary to wear these MG, players, parents and clubs need to be educated and shown how to carry out proper moulding of MFMG, to maximise the potential for these appliances to protect the dentoalveolar structures from injury. Dentists are ideally placed to do this, and should be trained so that they can then help parents and players to properly mould MFMG.
For CMG made from EVA, appropriate fit and retention is influenced by several factors including the working model characteristics, the temperature to which the
EVA sheet has been heated, and the particular formation technique used, i.e. vacuum- or pressure-forming (Mizuhashi and Koide, 2017a; Takahashi et al.,
2014a; Yonehata et al., 2003). In this study, all of the CMG assessed had appropriate retention. While this is encouraging, a definitive conclusion cannot be drawn on this due to the very small sample size (N = 4, 3.8%) involved.
Overall, inadequate retention of the majority of the MG used by the children in this sample may compromise their ability to protect the teeth in the event of an impact injury as they may be readily dislodged by impact forces instead of absorbing and dissipating them.
140
4.15.2.2 Mouthguard Extension to Cover the Teeth and Supporting
Structures
A MG cannot appropriately protect the teeth & supporting structures if it is not covering them. The labial flange should extend to 2mm short of the vestibular reflection to allow for free movement of the soft tissues and frenal attachments
(McClelland et al., 1999). This also allows for appropriate coverage of the anterior teeth and supporting tissues. In this study, 89 MG (83.96% of those MG assessed) had inadequate labial extension (Appendix 13.1, 13.4, 13.7).
The extension and design of the palatal flange affects MG comfort and wearability. If the palatal flange is too bulky and/or extends too far, with impingement on the tongue position, it can inhibit speaking and/or breathing with the MG in place, so players are less likely to wear it (Maeda et al., 2006).
Laboratory-based studies have found that palatal extension is less crucial for device retention, as long as the material properly engages the cervical undercut on the palatal surface of the teeth (Karaganeva et al., 2019; Maeda et al., 2009b,
2006; Yamada et al., 2006). In the current study, just under two-thirds (N = 64,
60.37%) of the MG had what was deemed as adequate palatal extension. This was defined as extending just beyond the palatal gingival margin of the teeth. In a field setting, the closeness of fit of the MG material around the cervical area of the palatal surface of the teeth could not be assessed.
Ideally, a MG will extend to cover all erupted maxillary teeth (Scott et al., 1994).
Given the age group included in this study, this was defined as covering as far as the last tooth in the maxillary arch. Just over half (N = 57, 53.77%) of the MG assessed in this study had adequate occlusal coverage. This is unsurprising given the fact that the majority of the MG were either SMG or MFMG. These are 141
fabricated in predetermined sizes and do not account for individual variation. It has been reported that 85% of MFMG do not appropriately cover the posterior molars in a study among adult basketball players in America (Kuebker et al.,
1986). The findings of the current study reflect an improvement compared to this; however, this study was carried out in a younger population so it may be that the
MFMG fit children and adolescents better than they do adults.
4.15.2.3 Mouthguard Occlusion
The occlusion on the MG in this study was assessed by checking for even, simultaneous balanced occlusion at all parts of the arch on each appliance.
Occlusion was determined as being adequate in 47 MG (45.19%) and inadequate in 57 MG (54.81% of the sample). There were no previous field studies assessing occlusion on MG. Laboratory studies and finite element analyses have established that balanced occlusion, especially anteriorly, is important for reducing dental injuries through impact absorption and force dissipation (Takeda et al., 2008, 2004a; Veríssimo et al., 2017). Less than half of the appliances in this study fulfilled this criterion for a MG which will appropriately protect teeth.
4.15.2.4 Mouthguard Surface Integrity
Of the MG assessed, just under half (N = 45, 46.88%) had borders that were classified as being smooth and well-rounded, indicating that there was some roughness or sharpness of the borders in the remainder of the sample (Appendix
13.3, 13.4, 13.6). This is concerning as the wearing of MG has been associated with the development of oral ulceration and frictional keratosis, with one study demonstrating an increase of 20% in the prevalence of soft tissue lesions in a sports team between the beginning and the end of a sports season (Glass et al., 142
2009). The current study design did not include a soft tissue assessment so it cannot be said whether the sharp borders were associated with any lesions. This could be investigated in future studies.
Surface integrity was intact in approximately half (N = 54, 50.94%) of the MG assessed. This was defined as a surface having no perforations or other disruptions, and is important for comfort, wearability and hygiene. Any roughness or disruption of the MG surface can lead to microbial colonisation (Almeida et al.,
2018). Many of the MFMG in this study had a harder outer shell and a softer inner gel component; in some of the appliances there was significant separation of these components (Appendix 13.6).
4.15.2.5 Mouthguard Colour
A small laboratory study previously showed that darker-coloured MG required greater force to dislodge them from a cast than lighter-coloured or transparent
MG (Del Rossi et al., 2008). The authors concluded that these dark MG had improved fit because darker-coloured materials absorb energy, achieving greater temperatures during heating, and therefore display improved adaptation around the dentition (Del Rossi et al., 2008).
In the current study, a greater proportion of lighter coloured MG had inadequate retention than both dark-coloured and transparent MG, and this difference was significant, in agreement with the findings of Del Rossi et al. (2008). There were no clinical studies in the literature against which to compare this study with regard to MG colour and retention. Therefore, recommendations on MG colour cannot be made on the basis of these results alone; it is an area which requires future research.
143
4.15.2.6 Summary: Mouthguard Fit in this Study
Mouthguards assessed in this study were of poor fit, as judged by the retention and extension. This is concerning, as the main condition of the GAA MG rules is that MG worn must be “properly fitted”, and that it is the responsibility of the player/parent to ensure this is the case. Judging by the fit of the MG worn in this study, children and parents do not seem to be aware of what constitutes a properly fitting MG.
4.15.3 Quality of Mouthguards Being Worn by Children Playing Sport in
Ireland: Mouthguard Thickness
There have been no other reports in the literature where investigators measured the thickness of existing MG being worn by sportspeople, without MG having been chosen and supplied to participants by the research teams. Del Rossi et al.
(2007) evaluated dimensional changes in MG provided to 11 high school athletes over 12 weeks; other than this, research into thickness of MG has been via either finite element analysis or laboratory-based research.
Mouthguard thickness was measured at the central incisors, canines and molar teeth. Thickness of the material is important for effective shock absorption and force dissipation (Barou et al., 2011). Palatal MG thickness was not measured in this study as it is not believed to be as important for shock absorption (Gómez-
Gimeno et al., 2019; Maeda et al., 2006; Yamada et al., 2006).
4.15.3.1 Labial thickness
The “ideal” labial thickness has been identified as being 3-4mm through the findings of laboratory and finite element analysis studies (Gialain et al., 2016; M.
Maeda et al., 2008; Verissimo et al., 2016; Westerman et al., 2002a). Labial
144
measurements were made for the anterior teeth only; the maxillary central incisors are the teeth most commonly affected by dental injuries (Lam, 2016;
Qudeimat et al., 2019).
The overall median labial thickness (central incisors and canines) of the MG in this sample was 4.08mm (IQR = 3.51mm – 4.53mm), and the median labial thickness of the central incisors only was 4.05mm (IQR = 3.51mm – 4.55mm).
The range of thicknesses was very wide for each site, reflecting the wide variety of MG types observed, even within the MFMG category. Children used a variety of MFMG brands and some displayed greater bulk than others (Appendix 13.2,
13.5, 13.6, 13.7).
The mean labial thickness of MFMG (4.58 ± 1.26mm) was significantly greater than that of both SMG and CMG. This is contrary to the findings of Guerard et al.
(2017), a laboratory-based study where it was found that MFMG thickness was less than that of the CMG in the study. It is also greater than the 3-4mm recommended by the materials science literature (Gialain et al., 2016; Maeda M. et al., 2008; Verissimo et al., 2016; Westerman et al., 2002a). The greater thickness in this study may reflect individual variation in the ability to appropriately self-adapt the MG; indeed, in some cases, MFMG appeared not to have been moulded at all, with a lack of indentations on the fitting surfaces (Appendix 13.6,
13.7).
The mean labial thickness of both SMG (3.67 ± 0.65mm) and CMG (3.18 ±
0.43mm) in this study, though less than that of MFMG, was within the 3-4mm thickness parameters suggested by laboratory studies and finite element
145
analyses (Gialain et al., 2016; Maeda M. et al., 2008; Verissimo et al., 2016;
Westerman et al., 2002a).
4.15.3.2 Occlusal thickness
The median anterior incisal edge thickness (incisors and canines) of MG in this study was 4.64mm (IQR = 2.98mm – 7.07mm). The median incisal edge thickness at the central incisors alone was 4.53mm (IQR = 2.91mm – 7.3mm).
These thicknesses are both at least 0.5mm greater than that recommended by
Westerman et al. (2002a), who reported 4mm as the ideal thickness for the incisal edge, as a location susceptible to indirect trauma from the opposing teeth.
Incisal edge thickness at the central incisors varied depending on the type of MG in question, with MFMG having the greatest thickness (5.18 ± 2.27mm), though this did not reach statistical significance. The mean incisal edge thickness of the
SMG was 4.08 ± 2.64 mm. Custom MG in this sample had the lowest mean incisal edge thickness (2.86 ± 0.62mm). It is well documented in laboratory studies that it is difficult to maintain the thickness of CMG at the incisal edge during thermoforming, due to the sharpness of the edge on the cast, and subsequent stretching and thinning of the heated EVA material away from the incisal edge
(Geary and Kinirons, 2008; Takahashi et al., 2016a; Tunc et al., 2013).
Occlusal thickness at the first permanent molars should not exceed 3mm to avoid risk of temporomandibular joint derangement (Murakami et al., 2008). This measurement was made at the distobuccal cusp of the first permanent molar.
This site was difficult to precisely establish in many MG; frequently, there were either indistinct or no tooth indentations on the fitting surface. The median thickness at the occlusal surface of the first permanent molars in this study was
146
3.9mm (IQR = 3.1mm – 6.4mm). This is greater than the 2-3mm thickness recommended in the literature (Maeda M. et al., 2008; Murakami et al., 2008).
Children in this study were not asked any questions in relation to joint discomfort in this study and none of the participants volunteered any complaints in relation to their bite or jaw joints; this would be worth investigating in a future study.
Mouth-formed MG (4.77 ± 1.94mm) were thicker than both SMG (4.64 ± 2.01mm) and CMG (2.58 ± 0.41mm) at the occlusal surface of the first permanent molars, with the result achieving statistical significance. This is contrary to findings of a laboratory study by Park et al. (1994), who reported that there was a reduction in occlusal thickness of 70-99% during forming of MFMG, attributing this to uncontrolled biting forces. However, many of the MFMG in this study did not appear to have been appropriately moulded (Appendix 13.6, 13.7), and this may account for the greater mean thickness among this cohort. In addition, the lower reliability of Examiner 3 for occlusal measurements limits the validity of these results.
Laboratory studies have shown that greater thinning occurs during thermoforming of CMG on the occlusal surface, similar to the incisal edges, due to the sharp cusp tips (Del Rossi and Leyte-Vidal, 2007; Geary and Kinirons, 2008; Mizuhashi et al., 2013). This appears to be reflected in the fact that the CMG in this sample had the lowest occlusal thickness; a definitive conclusion cannot be drawn on the basis of these results, however, given the small number of CMG assessed.
4.16 Limitations of the study
This research study has several limitations. The study was carried out in one sport – Gaelic football – and this sport has well-known and publicised rules
147
pertaining to the use of MG during training and matches at all age levels; therefore, this is a biased sample and does not represent patterns of MG wear across all sports in Ireland. This was a purposeful decision, however; the goal of the study was to assess compliance with these rules, and to examine as many
MG as possible to investigate the types and the quality of the appliances that were being selected for the children to wear. Gaelic football is a traditional Irish sport and is very popular among people of all ages; during the development of the study protocol, it was felt that selecting the sample from Gaelic football players would therefore be more likely to yield a meaningful sample of players with their MG, and their parents.
The sample size in this study, though the first of its kind, was small and unevenly distributed among clubs (Table 3.3). It was planned to stratify data according to club to analyse knowledge, attitudes and behaviours according to club; this was not possible due to the lower counts of participants from two of the included clubs.
Club public relations officers were acting as gatekeepers so the research team could not directly contact players or parents prior to the appointed date. The clubs with larger participant numbers had engaged in publicising the research study on their social media channels in the days leading up to data collection, and had sent email and WhatsApp reminders on the day itself, so there was a greater level of awareness among players and parents in those two clubs. In the clubs with smaller numbers, the same promotion did not take place prior to data collection dates, awareness of the study was much lower, and recruitment of participants was very challenging at those visits, with no potential for a return date to either club.
148
Accessing and recruiting participants for this study was challenging for a variety of reasons. Ethical approval from the Faculty of Health Sciences Research Ethics
Committee at Trinity College Dublin and approval from the Medical, Scientific and
Welfare committees of both the GAA and LGFA required additional amendments, specifically in relation to consent and GDPR regulations. Carrying out research in children requires particular attention to be paid to all elements of consent, child safeguarding and child welfare. It was initially planned to complete data collection in Spring 2019; however, it took until April 2019 for all necessary approvals and permissions to be in place. The club invitations were then sent and had to be approved by each club’s executive committee before plans to visit clubs could be put in place. Training ceased for the summer months in mid-June 2019, so each club requested for data collection to be postponed until Autumn 2019.
Clubs did not wish for data collection to be carried out on competition days, and instead club visits took place at appointed times during evening training sessions.
This had several disadvantages. Parents tended to drop children off for training and leave, returning only to collect them at the end of the session; some children were brought to and from training in a carpool with other players’ parents.
Therefore, it was difficult to recruit players whose parents were also willing to consent to their participation, and who were willing to participate in the parent questionnaire themselves. Several team mentors (coaches), and children themselves, did not wish for players to miss any training; therefore, the research team were dependent on children and their parents presenting either before or after the training session. This presented logistical challenges with managing the volume of participants presenting at one time, and participants frequently had to wait some time for their turn, which may have discouraged their team-mates from
149
participating. Recruitment was also complicated by weather; data collection took place during Autumn-Winter 2019, when there were several significant storms.
On several occasions, the research team were present at the club, but training had either been cancelled on the day or else few players were in attendance, with even fewer parents staying for the duration of the session. In future, Spring-
Summer would be a more sensible time to collect data for such a study.
Ideally, a study like this would have included clubs and teams from all over the country to gain a more comprehensive insight into the use of and attitudes towards MG in Gaelic football. Logistics did not permit travelling outside Dublin, however, so efforts were made to select clubs from a variety of areas within the city to recruit as diverse a sample as possible.
This study was likely subject to self-selection bias on several levels. Fourteen clubs were invited to participate; ultimately only 4 agreed to participate. Two further clubs had initially agreed to participate but later failed to respond to repeated communications regarding setting up club visits. No communication was received from the remaining 8 clubs, who may have decided against participation if they were less involved or proactive in promoting the use of MG.
Players and parents who were aware of the need for MG, and who were regularly wearing MG, may have been more likely to present themselves for participation in the study. This may have skewed the results to indicate a greater level of compliance than is actually present.
Players may also have been more likely to wear their MG on the evening of data collection, knowing that a dentist was going to be present. The fact that parents and the players were aware that the examining team was composed of dentists
150
may also have influenced their responses to the questionnaires – the so-called
Hawthorne Effect (participants may be more likely to alter their behaviour in the knowledge of their being under observation). The findings of this study must be considered in the context of these potential sources of bias.
From a procedural point of view, it would have been preferable to have just one examiner for consistency of measurement. During the calibration all examiners had high values of agreement for qualitative measurements (assessment for signs of trauma; MG type and quality assessment). For quantitative variables (i.e.
MG thickness measurements), Examiner 1 and Examiner 2 showed greater consistency in measurements than Examiner 3. Ideally, Examiners 1 and 2 only would have completed data collection; however, due to examiner availability for data collection, all 3 examiners were needed (2 at a time). Examiner 1 (ICC labial
= .918, ICC occlusal = .799) carried out the greatest number of assessments (N
= 64/121) compared to both Examiner 2 (N = 22/121 subjects measured; ICC labial = 0.918, ICC occlusal = 0.926) and Examiner 3 (N = 35/121 subjects measured; ICC labial = 0.819, ICC occlusal = 0.475). Nevertheless, this variability is a limitation of the thickness measurement portion of this study, especially the occlusal measurements.
There is no validated questionnaire for research in this area, with each study investigating knowledge and awareness in relation to trauma and MG use using a different questionnaire. This study aimed to compare the responses to the parent questionnaire to the findings of O’Malley et al. (2012), which at the time of protocol development was the most recent data published in relation to knowledge and attitudes relating to MG use in Ireland. The parent questionnaires in this study were formulated based on questions from the paper published by 151
O’Malley et al. (2012), with the addition of questions specific to MG use for Gaelic football, MG hygiene-related behaviours, and the price parents were willing to pay for a CMG for their child. The children’s questionnaire was developed based on the parent questionnaire with additional questions relating to when they wore
MG, how they felt about their MG, and MG hygiene-related behaviours. Ideally a standardised, validated questionnaire would be developed for universal use in this type of research, to allow for direct comparisons between studies.
Dependence on parent and child recall, and on dentist identification of signs of previous trauma to permanent teeth, is an unreliable means of determining the prevalence of trauma in a population. The current study asked parents and children if there had “ever” been an injury to the child’s permanent teeth (i.e. measure of trauma prevalence); previous Irish questionnaire-based studies asked only about history of injury within the previous year (i.e. measure of trauma incidence) (Evans and O’Malley, 2018; O’Malley et al., 2012). Parents and children differed in their responses, with poor agreement relating to past history of dental trauma both in general and during sports. Dentists’ estimates of trauma incidence according to signs of trauma were different from both parent- and child- reported trauma. Therefore, definitive conclusions cannot be drawn from the current study on the prevalence of traumatic dental injuries among 9-16-year-old children playing sports in Ireland; a prospective study design would be required for greater accuracy.
152
4.17 Conclusions
4.17.1 Experience of Traumatic Dental Injuries Among Children in this
Sample
Among this population of 9-16-year-old male and female Gaelic football players,
9.9% of children reported having experienced a sports-related dental injury at some time in the past, with 83.3% reporting having been wearing a MG at the time of injury.
In contrast, only 2.54% of parents in the sample reported that their child had suffered a sports-related dental injury, with none of them reportedly wearing a
MG at the time of injury. Parents and children were in agreement on their answers to this question less than half of the time.
Dentists observed signs of trauma in 12.4% of the sample, the majority of which were enamel fractures (66.67%). These signs were not necessarily observed in those children who reported a past history of trauma, with dentist and child reports in agreement only 23.6% of the time.
The variability of these reports makes it difficult to estimate the prevalence of sports-related dental injuries in this population.
4.17.2 Compliance with GAA Mouthguard Rules
Mouthguards are routinely worn by children playing Gaelic football. Player- reported compliance with the GAA MG rules was generally high: 99.17% of the sample reported wearing their MG for matches, and 80.83% reported wearing the
MG for training. This represents a reduction in compliance of 18.37% from competition to training. Children were less likely to comply with MG rules during training as they grew older. 153
4.17.3 Knowledge and Attitudes Relating to Mouthguard Use Among
Parents and Children in this Sample
Attitudes to the use of MG among players and their parents in this sample were generally positive; 75% of children reported liking their MG and were more likely to report this if they could speak and/or breathe properly while wearing it.
Only 14% of children were wearing their MG for all sports that they participated in; this was in contrast to 65.9% of parents believing that their children were wearing MG for all sports. Most children reported not wearing MG for all sports because there were no MG rules in place.
Most parents (73.73%) believed that CMG would be most likely to protect their child’s teeth in the event of a dental injury. In contrast, only 7.63% reported that their child had a CMG. Parents were prepared to pay a median price of €35.00
(IQR = €20.00 - €50.00) for such a MG for their child.
Knowledge in relation to MG hygiene was generally lacking; there was poor agreement between child and parent reports regarding storage and cleaning of the MG.
4.17.4 Quality of Mouthguards worn by Children in this Sample
This study has found that, while a variety of MG are being worn, MFMG were the most popular choice in this population. The majority of MG had inadequate retention and inadequate labial extension. Adequate occlusal coverage, balanced occlusion, smooth rounded borders and proper surface integrity were each present in only approximately half of MG assessed. Mean labial, incisal and occlusal thickness were each greater than that recommended in the literature, but there was notable variability in thickness at all sites. Mouth-formed MG were
154
significantly thicker than both SMG and CMG. This study cannot draw any conclusions on the quality of CMG as the number of these devices in the current sample was too small. Overall, the quality of MG assessed in this study was poor.
Based on the findings of this study, thickness cannot be the sole criterion for the protective ability of a MG; retention and labial extension are just as important for preventing damage to dentoalveolar structures.
4.17.5 Recommendations and Future Directions
This is the first known observational study to investigate the type and quality of
MG currently worn by participants in any sport in a field setting. In Ireland, it is the first study to investigate the attitudes relating to MG use through questionnaire-based surveys of both parents and children, in a sporting setting, concurrent with an examination of the MG in situ. Previous Irish studies only surveyed parents and were carried out in a primary school setting.
Given the fact that the GAA, as the parent organisation, has mandated the MG rules, and the fact that the findings of this study have reflected a remarkable rate of compliance with these rules, it would be interesting to repeat this study among another sporting organisation such as rugby or hockey, where there is a culture of MG wear, to establish if behaviours differ in any way. Equally, it would be interesting to conduct a survey of soccer players and their parents to establish their knowledge and experience of dental trauma, and their attitudes towards the use of MG.
In general, there is compliance with the wearing of MG despite many of the MG not being retentive with inadequate labial extension. This study highlights the need for education of players, parents and club personnel on what constitutes a
155
“properly fitted” MG. The dental profession has a role in informing patients and sportspeople about the need for MG, which type to wear, and how to properly care for it. Players need to be educated as to when a replacement MG is required.
Custom MG should be encouraged, but in situations where MFMG are required, dentists are well-placed to show parents and children how to appropriately mould the MG around the teeth and soft tissues. Players should be encouraged to bring their MG with them when attending their regular check-ups, so that dentists can assess the MG quality and fit.
Sports participants must be educated in the need for wearing MG for all contact sports, for both training and competition, to reduce their risk of and from dental traumatic injuries.
156
5 References
Abbott, P. V, Salgado, J.C., 2014. Strategies to minimise the consequences of trauma to the teeth. Oral Health Dent. Manag. 13, 229–42. Ain, T.S., Telgi, R.L., Sultan, S., Tangade, P., Telgi, C.R., Tirth, A., Pal, S.K., Gowhar, O., Tandon, V., 2016. Prevalence of traumatic dental injuries to anterior teeth of 12-year-old school children in Kashmir, India. Arch. Trauma Res. 5, 1–8. https://doi.org/10.5812/atr.24596 Al Sari, S., Kowash, M., Hussein, I., Al-Halabi, M., 2019. An Educational Initiative for Dubai School Nurses and Physical Education Teachers on the Management of Traumatic Dental Injuries. J. Sch. Nurs. 35, 359–366. https://doi.org/10.1177/1059840518780306 Aljohani, Y.R., Alfaifi, K.H., Redwan, S.K., Sabbahi, D.A., Zahran, M.H., 2017. Dental injuries in taekwondo athletes practicing in Saudi Arabia. Saudi Med. J. 38, 1143– 1147. https://doi.org/10.15537/smj.2017.11.21111 Almeida, M.H., Ceschim, G.V., Iorio, N.L.P.P., Póvoa, H.C.C., Cajazeira, M.R.R., Guimarães, G.S., Antunes, L.S., Antunes, L.A.A., 2018. Influence of thickness, color, and polishing process of ethylene-vinyl-acetate sheets on surface roughness and microorganism adhesion. Dent. Traumatol. 34, 51–57. https://doi.org/10.1111/edt.12374 American Academy of Pediatric Dentistry, 2016. Policy on Prevention of Sports-related Orofacial Injuries. Pediatr. Dent. 38, 76–80. Andersson, L., 2013. Epidemiology of Traumatic Dental Injuries. Pediatr. Dent. 35, 102–5. https://doi.org/10.1016/j.jtrangeo.2007.06.002 Andersson, L., Petti, S., Day, P., Kenny, K., Glendor, U., Andreasen, J.O., 2019. Classification, Epidemiology and Etiology, in: Andreasen, J.O., Andreasen, F.M., Andersson, L. (Eds.), Textbook and Color Atlas of Traumatic Injuries to the Teeth. John Wiley and Sons Ltd, Hoboken, USA, pp. 252–294. Andrade, R.A., Evans, P.L.S., Almeida, A.L.S., da Silva, J. de J.R., Guedes, A.M.L., Guedes, F.R., Ranalli, D.N., Modesto, A., Tinoco, E.M.B., 2010. Prevalence of dental trauma in Pan American games athletes. Dent. Traumatol. 26, 248–253. https://doi.org/10.1111/j.1600-9657.2010.00884.x Andreasen, J.O., Vinding, T.R., Christensen, S.S.A., 2006. Predictors for healing complications in the permanent dentition after dental trauma. Endod. Top. 14, 20– 27. https://doi.org/10.1111/j.1601-1546.2008.00228.x Arikan, V., Sönmez, H., 2012. Knowledge level of primary school teachers regarding traumatic dental injuries and their emergency management before and after receiving an informative leaflet. Dent. Traumatol. 28, 101–107. https://doi.org/10.1111/j.1600-9657.2011.01042.x Årtun, J., Behbehani, F., Al-Jame, B., Kerosuo, H., 2005. Incisor trauma in an adolescent Arab population: Prevalence, severity, and occlusal risk factors. Am. J. Orthod. Dentofac. Orthop. 128, 347–352. https://doi.org/10.1016/j.ajodo.2004.06.032 Association of Boxing Commissions and Combative Sports, 2018. Unified Rules of Mixed Martial Arts Last accessed 13 July 2020 157
158
https://doi.org/10.23804/ejpd.2018.19.03.10 Braham, R., Finch, C., McIntosh, A., McCrory, P., 2004. Community football players’ attitudes toward protective equipment - A pre-season measure. Br. J. Sports Med. 38, 426–430. https://doi.org/10.1136/bjsm.2002.004051 Brin, I., Ben-Bassat, Y., Heling, I., Brezniak, N., 2000. Profile of an orthodontic patient at risk of dental trauma. Dent. Traumatol. 16, 111–115. https://doi.org/10.1034/j.1600-9657.2000.016003111.x British Boxing Board of Control, 2020. Rules of Boxing. Last accessed 13 July 2020. http://bbbofc.com/content/rules-boxing-0. British Orthodontic Society, 2019. Mouthguards. Patient Information Leaflet. Last accessed 13 July 2020.
159
Collares, K., Correa, M., da Silva, I., Hallal, P., Demarco, F., 2014. Effect of wearing mouthguards on the physical performance of soccer and futsal players: a randomized cross-over study. Dent. Traumatol. 30, 55–59. https://doi.org/10.1111/edt.12040 Collins, C.L., Mckenzie, L.B., Ferketich, A.K., Andridge, R., Xiang, H., Comstock, R.D., 2016. Dental injuries sustained by high school athletes in the United States, from 2008/2009 through 2013/2014 academic years. Dent. Traumatol. 32, 121–127. https://doi.org/10.1111/edt.12228 Collins, C.L., McKenzie, L.B., Roberts, K.J., Fields, S.K., Comstock, R.D., 2015. Mouthguard BITES (Behavior, Impulsivity, Theory Evaluation Study): What Drives Mouthguard Use Among High School Basketball and Baseball/Softball Athletes. J. Prim. Prev. 36, 323–334. https://doi.org/10.1007/s10935-015-0402-7 Cortelli, S.C., Costa, F.O., Rode, S. de M., Haas, A.N., de Andra, A.K.P., Pannuti, C.M., Escobar, E.C., de Almeida, E.R., Cortelli, J.R., Pedrazzi, V., 2014. Mouthrinse recommendation for prosthodontic patients. Braz. Oral Res. 28, 1–9. https://doi.org/10.1590/1807-3107BOR-2014.vol28.0020 Croll, T.P., Castaldi, C.R., 2004. Custom sports mouthguard modified for orthodontic patients and children in the transitional dentition. Pediatr. Dent. 26, 417–420. Croll, T.P., Castaldi, C.R., 1996. Customized protective mouthguards for orthodontic patients. J. Clin. Orthod. 30, 15–19. D’Ercole, S., Tieri, M., Martinelli, D., Ciaravino, C., Fulco, D., Tripodi, D., 2020. Microbial Contamination and Disinfection of Sport Mouthguard: In Vitro Study. Curr. Microbiol. 77, 246–253. https://doi.org/10.1007/s00284-019-01834-1 de Wet, F.A., Heyns, M., Pretorius, J., 1999. Shock absorption potential of different mouth guard materials. J. Prosthet. Dent. 82, 301–306. Del Rossi, G., Leyte-Vidal, M.A., 2007. Fabricating a better mouthguard. Part I: Factors influencing mouthguard thinning. Dent. Traumatol. 23, 149–154. https://doi.org/10.1111/j.1600-9657.2006.00436.x Del Rossi, G., Lisman, P., Leyte-Vidal, M.A., 2007. A preliminary report of structural changes to mouthguards during 1 season of high school football. J. Athl. Train. 42, 47–50. Del Rossi, G., Lisman, P., Signorile, J., 2008. Fabricating a better mouthguard. Part II: The effect of color on adaptation and fit. Dent. Traumatol. 24, 197–200. https://doi.org/10.1111/j.1600-9657.2007.00570.x Delilbasi, C., Yamazawa, M., Nomura, K., Iida, S., Kogo, M., 2004. Maxillofacial fractures sustained during sports played with a ball. Oral Surg. Oral Med. Oral Pathol. Oral Radiol. Endod. 97, 23–27. https://doi.org/10.1016/j.tripleo.2003.10.008 DeYoung, A.K., Robinson, E., Godwin, W.C., 1994. Comparing comfort and wearability: custom-made vs. self-adapted mouthguards. J. Am. Dent. Assoc. 125, 1112–1118. Duarte-Pereira, D.M.V., Del Rey-Santamaria, M., Javierre-Garces, C., Barbany-Cairo, J., Paredes-Garcia, J., Valmaseda-Castellon, E., Berini-Aytes, L., Gay-Escoda, C., 2008. Wearability and physiological effects of custom-fitted vs self-adapted mouthguards. Dent. Traumatol. 24, 439–442. https://doi.org/10.1111/j.1600-
160
9657.2008.00595.x Duddy, F.A., Weissman, J., Lee, R.A.S., Paranjpe, A., Johnson, J.D., Cohenca, N., 2012. Influence of different types of mouthguards on strength and performance of collegiate athletes: a controlled-randomized trial. Dent. Traumatol. 28, 263–267. https://doi.org/10.1111/j.1600-9657.2011.01106.x Dursun, E., Ilarslan, Y.D., Ozgul, O., Donmez, G., 2015. Prevalence of dental trauma and mouthguard awareness among weekend warrior soccer players. J. Oral Sci. 57, 191–194. https://doi.org/10.2334/josnusd.57.191 Emery, C.A., Black, A.M., Kolstad, A., Martinez, G., Nettel-Aguirre, A., Engebretsen, L., Johnston, K., Kissick, J., Maddocks, D., Tator, C., Aubry, M., Dvořák, J., Nagahiro, S., Schneider, K., 2017. What strategies can be used to effectively reduce the risk of concussion in sport? A systematic review. Br. J. Sports Med. 51, 978–984. https://doi.org/10.1136/bjsports-2016-097452 Evans, D.S., O’Malley, M., 2018. Mouth guard use among children: Has the GAA policy made a difference? Ireland’s Dent. Mag. Farrington, T., Coward, T., Onambele-Pearson, G., Taylor, R.L., Earl, P., Winwood, K., 2016. The effect of model inclination during fabrication on mouthguard calliper- measured and CT scan-assessed thickness. Dent. Traumatol. 32, 14–21. https://doi.org/10.1111/edt.12192 Fédération Interationale de Football Association, 2015. FIFA Laws of the Game 2015/2016. Last accessed 13 July 2020
Gaelic Athletic Association, 2019. GAA Official Guide. Dublin, Ireland. Gaelic Athletic Association, 2017. Mouthguards and Hurling Helmets. Last accessed 13 July 2020
162
Glendor, U., Göransson, A., 2013. Attitudes towards the use of mouth and face guards in Swedish ice hockey: part 2. Results. Dent. Traumatol. 29, 432–444. https://doi.org/10.1111/edt.12033 Glendor, U., Jonsson, D., Halling, A., Lindqvist, K., 2008. Direct and indirect costs of dental trauma in Sweden: a 2-year prospective study of children and adolescents. Community Dent. Oral Epidemiol. 29, 150–160. https://doi.org/10.1111/j.1600- 0528.2001.290210.x Gómez-Gimeno, À., Zamora-Olave, C., Cordobés-Navarro, M., Willaert, E., Martinez- Gomis, J., 2019. Satisfaction with shortening the palatal extension of a mouthguard for water polo players: A randomized crossover study. Dent. Traumatol. 35, 135–141. https://doi.org/10.1111/edt.12455 Gould, T.E., Piland, S.G., Shin, J., Hoyle, C.E., Nazarenko, S., 2009a. Characterization of mouthguard materials: Physical and mechanical properties of commercialized products. Dent. Mater. 25, 771–780. https://doi.org/10.1016/j.dental.2008.12.005 Gould, T.E., Piland, S.G., Shin, J., McNair, O., Hoyle, C.E., Nazarenko, S., 2009b. Characterization of mouthguard materials: Thermal properties of commercialized products. Dent. Mater. 25, 1593–1602. https://doi.org/10.1016/j.dental.2009.08.003 Greasley, A., Imlach, G., Karet, B., 1998. Application of a standard test to the in vitro performance of mouthguards. Br. J. Sports Med. 32, 17–19. https://doi.org/10.1136/bjsm.32.1.17 Greasley, A., Karet, B., 1997. Towards the development of a standard test procedure for mouthguard assessment. Br. J. Sports Med. 31, 31–35. https://doi.org/10.1136/bjsm.31.1.31 Green, J.I., 2017. The Role of Mouthguards in Preventing and Reducing Sports-related Trauma. Prim. Dent. J. 6, 27–34. https://doi.org/10.1308/205016817821281738 Green, M.S., Benson, A.K., Martin, T.D., 2018. Effect of Mouthguard Use on Metabolic and Cardiorespiratory Responses to Aerobic Exercise in Males. Res. Q. Exerc. Sport 89, 183–189. https://doi.org/10.1080/02701367.2018.1451816 Grewal, N., Kumari, F., Tiwari, U., 2015. Comparative evaluation of shock absorption ability of custom-fit mouthguards with new-generation polyolefin self-adapting mouthguards in three different maxillary anterior teeth alignments using Fiber Bragg Grating (FBG) sensors. Dent. Traumatol. 31, 294–301. https://doi.org/10.1111/edt.12151 Guérard, S., Barou, J.-L.L., Petit, J., Poisson, P., 2014. Characterization of mouth- formed mouthguards: Thermal performance. Dent. Mater. J. 33, 799–804. https://doi.org/10.4012/dmj.2014-044 Guérard, S., Barou, J.L., Petit, J., Poisson, P., 2017. Characterization of mouthguards: Impact performance. Dent. Traumatol. 33, 281–287. https://doi.org/10.1111/edt.12329 Hanson, N.J., Lothian, D.D., Miller, C.L., Michael, T.J., Miller, M.G., 2018. Over-the- counter performance enhancing mouthguards are unable to decrease blood lactate and improve power output during a Wingate anaerobic test (WAnT). J. Exerc. Sci. Fit. 16, 83–86. https://doi.org/10.1016/j.jesf.2018.07.001 Hawn, K.L., Visser, M.F., Sexton, P.J., 2002. Enforcement of mouthguard use and
163
athlete compliance in National Collegiate Athletic Association men’s collegiate ice hockey competition. J. Athl. Train. 37, 204–208. Hegde, A.M., Pradeep Kumar, K.N., Varghese, E., 2010. Knowledge of dental trauma among mothers in Mangalore. Dent. Traumatol. 26, 325–329. https://doi.org/10.1111/j.1600-9657.2010.00905.x Hickey, J.C., Morris, A.L., Carlson, L.D., Seward, T.E., 1967. The relation of mouth protectors to cranial pressure and deformation. J. Am. Dent. Assoc. 74, 735–740. Hoffmann, J., Alfter, G., Rudolph, N.K., Goz, G., 1999. Experimental comparative study of various mouthguards. Endod. Dent. Traumatol. 15, 157–163. Ilia, E., Metcalfe, K., Heffernan, M., 2014. Prevalence of dental trauma and use of mouthguards in rugby union players. Aust. Dent. J. 59, 473–481. https://doi.org/10.1111/adj.12223 International Association for Dental Traumatology, 2020. For Patients. Last accessed 13 July 2020).
Coefficients for Reliability Research. J. Chiropr. Med. 15, 155–163. https://doi.org/10.1016/j.jcm.2016.02.012 Kroon, J., Cox, J.A., Knight, J.E., Nevins, P.N., Kong, W.W., 2016. Mouthguard Use and Awareness of Junior Rugby League Players in the Gold Coast, Australia: A Need for More Education. Clin. J. Sport Med. Off. J. Can. Acad. Sport Med. 26, 128–132. https://doi.org/10.1097/JSM.0000000000000206 Kuebker, W.A., Morrow, R.M., Cohen, P.A., 1986. Do mouth-formed mouth guards meet the NCAA rules? Phys. Sportsmed. 14, 69–74. https://doi.org/10.1080/00913847.1986.11709100 Labella, C.R., Smith, B.W., Sigurdsson, A., 2002. Effect of mouthguards on dental injuries and concussions in college basketball. Med. Sci. Sports Exerc. 34, 41–44. https://doi.org/10.1097/00005768-200201000-00007 Ladies Gaelic Football Association, 2013. Ladies Gaelic Football Association Introduce Mouthguard Rule. Last accessed 13 July 2020 < https://ladiesgaelic.ie/ladies- gaelic-football-association-introduce-mouthguard-rule/> Lam, R., 2016. Epidemiology and outcomes of traumatic dental injuries: A review of the literature. Aust. Dent. J. 61, 4–20. https://doi.org/10.1111/adj.12395 Lee, J.W., Heo, C.K., Kim, S.J., Kim, G.T., Lee, D.W., 2013. Mouthguard use in Korean taekwondo athletes-awareness and attitude. J. Adv. Prosthodont. 5, 147–152. https://doi.org/10.4047/jap.2013.5.2.147 Levin, L., Zadik, Y., 2012. Education on and prevention of dental trauma: It’s time to act! Dent. Traumatol. 28, 49–54. https://doi.org/10.1111/j.1600- 9657.2011.01060.x Liew, A.K.C., Abdullah, D., Wan Noorina, W.A., Khoo, S., 2014. Factors associated with mouthguard use and discontinuation among rugby players in Malaysia. Dent. Traumatol. 30, 461–467. https://doi.org/10.1111/edt.12114 Maeda, M., Takeda, T., Nakajima, K., Shibusawa, M., Kurokawa, K., Shimada, A., Takayama, K., Ishigami, K., 2008. In search of necessary mouthguard thickness. Part 1: From the viewpoint of shock absorption ability. Nihon Hotetsu Shika Gakkai Zasshi 52, 211–219. https://doi.org/10.2186/jjps.52.211 Maeda, Y., Kumamoto, D., Yagi, K., Ikebe, K., 2009a. Effectiveness and fabrication of mouthguards. Dent. Traumatol. 25, 556–564. https://doi.org/10.1111/j.1600- 9657.2009.00822.x Maeda, Y., Machi, H., Tsugawa, T., 2006. Influences of palatal side design and finishing on the wearability and retention of mouthguards. Br. J. Sports Med. 40, 1006–1008. https://doi.org/10.1136/bjsm.2006.030874 Maeda, Y., Matsuda, S., Tsugawa, T., Maeda, S., 2008. A modified method of mouthguard fabrication for orthodontic patients. Dent. Traumatol. 24, 475–478. https://doi.org/10.1111/j.1600-9657.2008.00596.x Maeda, Y., Yonehata, Y., Satoh, H., 2009b. Mouthguard retention: is design or accuracy of fit more critical? Quintessence Int. 40, e13-8. Maladière, E., Bado, F., Meningaud, J.P., Guilbert, F., Bertrand, J.C., 2001. Aetiology and incidence of facial fractures sustained during sports: A prospective study of 140 patients. Int. J. Oral Maxillofac. Surg. 30, 291–295. https://doi.org/10.1054/ijom.2001.0059 165
Marcano-Caldera, M., Mejía-Cardona, J.L., Parra Sanchez, J.H., de la Espriella, C.M., Morales, E.C., Varón, G.S., Díaz, M.G., Mesa, N.F., Villegas, P.E., Reyes, P.B., Sanchez, P.R., Fernández, P.M., Gómez-Scarpetta, R.Á., Alfaro, V.B., Cifuentes Aguirre, O.L., López Soto, O.P., Sigurdsson, A., 2018. Knowledge about emergency dental trauma management among school teachers in Colombia: A baseline study to develop an education strategy. Dent. Traumatol. 34, 164–174. https://doi.org/10.1111/edt.12393 Marcenes, W., Murray, S., 2002. Changes in prevalence and treatment need for traumatic dental injuries among 14-year-old children in Newham, London: a deprived area. Community Dent. Health 19, 104–108. Matalon, V., Brin, I., Moskovitz, M., Ram, D., 2008. Compliance of children and youngsters in the use of mouthguards. Dent. Traumatol. 24, 462–467. https://doi.org/10.1111/j.1600-9657.2008.00600.x McClelland, C., Kinirons, M., Geary, L., 1999. A preliminary study of patient comfort associated with customised mouthguards. Br. J. Sports Med. 33, 186–189. McCrory, P., Meeuwisse, W.H., Aubry, M., Cantu, R.C., Dvorak, J., Echemendia, R.J., Engebretsen, L., Johnston, K., Kutcher, J.S., Raftery, M., Sills, A., Benson, B.W., Davis, G.A., Ellenbogen, R., Guskiewicz, K.M., Herring, S.A., Iverson, G.L., Jordan, B.D., Kissick, J., McCrea, M., McIntosh, A.S., Maddocks, D., Makdissi, M., Purcell, L., Putukian, M., Schneider, K., Tator, C.H., Turner, M., 2013. Consensus statement on concussion in sport: the 4th International Conference on Concussion in Sport, Zurich, November 2012. J. Athl. Train. 48, 554–575. https://doi.org/10.4085/1062-6050-48.4.05 Meade, M.J., 2018. Sports Mouthguards and Orthodontic Treatment. Dent. Update 45, 848–858. https://doi.org/https://doi.org/10.12968/denu.2018.45.9.848 Milward, P.J., Jagger, R.G., 1995. Heat-cured silicone bimaxillary mouthguard. J. Prosthet. Dent. 74, 432–433. Mizuhashi, F., Koide, K., 2020. Difference in pressure-formed mouthguard thickness according to the laminate procedure. Dent. Traumatol. 36, 198–202. https://doi.org/10.1111/edt.12516 Mizuhashi, F., Koide, K., 2019. Vacuum-formed mouthguard fabrication to obtain proper fit using notched sheet. Dent. Traumatol. https://doi.org/10.1111/edt.12463 Mizuhashi, F., Koide, K., 2018. Pressure-forming method using a single-mouthguard sheet. Dent. Traumatol. 34, 41–45. https://doi.org/10.1111/edt.12368 Mizuhashi, F., Koide, K., 2017a. Formation of vacuum-formed and pressure-formed mouthguards. Dent. Traumatol. 33, 295–299. https://doi.org/10.1111/edt.12337 Mizuhashi, F., Koide, K., 2017b. Appropriate fabrication method for vacuum-formed mouthguards. Dent. Traumatol. 33, 110–113. https://doi.org/10.1111/edt.12302 Mizuhashi, F., Koide, K., Mizuhashi, R., 2018. Mouthguard sheet temperature after heating under pressure former. Dent. Traumatol. https://doi.org/10.1111/edt.12458 Mizuhashi, F., Koide, K., Mizuhashi, R., 2017. Influence of working model angle on the formation of a pressure-formed mouthguard. Dent. Traumatol. 33, 189–193. https://doi.org/10.1111/edt.12317 Mizuhashi, F., Koide, K., Mizuhashi, R., 2016a. Influence of working model position on the formation of a pressure-formed mouthguard. Dent. Traumatol. 32, 469–473. 166
https://doi.org/10.1111/edt.12274 Mizuhashi, F., Koide, K., Takahashi, M., 2016b. New fabrication method to maintain proper mouthguard thickness. Dent. Traumatol. 32, 85–89. https://doi.org/10.1111/edt.12208 Mizuhashi, F., Koide, K., Takahashi, M., 2016c. Difference in vacuum-formed mouthguard thickness according to timing of vacuum application. Dent. Traumatol. 32, 306–310. https://doi.org/10.1111/edt.12240 Mizuhashi, F., Koide, K., Takahashi, M., 2015a. Variations in mouthguard thickness according to fabrication method. Dent. Traumatol. 31, 130–135. https://doi.org/10.1111/edt.12128 Mizuhashi, F., Koide, K., Takahashi, M., 2015b. Thickness and fit of mouthguards adjusted by notching thermoplastic sheets under different heating conditions. Dent. Traumatol. 31, 288–293. https://doi.org/10.1111/edt.12143 Mizuhashi, F., Koide, K., Takahashi, M., 2014a. Thickness and fit of mouthguards according to heating methods. Dent. Traumatol. 30, 60–64. https://doi.org/10.1111/edt.12046 Mizuhashi, F., Koide, K., Takahashi, M., 2014b. Assessing change in mouthguard thickness according to the thickness of the original mouthguard sheet. Dent. Traumatol. 30, 468–471. https://doi.org/10.1111/edt.12115 Mizuhashi, F., Koide, K., Takahashi, M., 2013. Thickness and fit of mouthguards according to a vacuum-forming process. Dent. Traumatol. 29, 307–312. https://doi.org/10.1111/edt.12004 Murakami, S., Maeda, Y., Ghanem, A., Uchiyama, Y., Kreiborg, S., 2008. Influence of mouthguard on temporomandibular joint. Scand. J. Med. Sci. Sports 18, 591–595. https://doi.org/10.1111/j.1600-0838.2007.00698.x Namba, E.L., Strapasson, A., Baratto, S.P., Tomazinho, P.H., Namba, E.L., 2013. Sanitization of sports mouthguards. Rsbo 10, 72–75. National Collegiate Athletic Association, 2020. NCAA Playing Rules. National Collegiate Athletic Association, 2019a. Football Rules and Interpretations. Indianapolis, IN. National Collegiate Athletic Association, 2019b. Women’s Lacrosse 2020-2021 Rules and Interpretations. Indianapolis, IN. National Collegiate Athletic Association, 2019c. Wrestling 2019-2020 and 2020-2021 Rules Book. Indianapolis, IN. National Collegiate Athletic Association, 2019d. Ice Hockey 2018-2019 and 2019-2020 Rules and Interpretations. Indianapolis, IN. National Collegiate Athletic Association, 2018. Men’s Lacrosse - 2019 and 2020 Rules and Interpretations. Indianapolis, IN. National Federation of State High School Associations Sports Medicine Advisory Committee, 2018. Position Statement and Recommendations for Mouthguard Use in Sports. Newsome, P.R.H., Tran, D.C., Cooke, M.S., 2001. The role of the mouthguard in the prevention of sports-related dental injuries: a review. Int. J. Paediatr. Dent. 11, 167
396–404. Nguyen, P.M.T., Kenny, D.J., Barrett, E.J., 2004. Socio-economic burden of permanent incisor replantation on children and parents. Dent. Traumatol. 20, 123–133. https://doi.org/10.1111/j.1600-4469.2004.00235.x Norton, E., O’Connell, A.C., 2012. Traumatic dental injuries and their association with malocclusion in the primary dentition of Irish children. Dent. Traumatol. 28, 81–86. https://doi.org/10.1111/j.1600-9657.2011.01032.x O’Malley, M., Evans, D.S., Hewson, A., Owens, J., 2012. Mouthguard use and dental injury in sport: a questionnaire study of national school children in the west of Ireland. J. Ir. Dent. Assoc. 58, 205–211. Ogawa, T., Yamasaki, S., Honda, M., Terao, Y., Kawabata, S., Maeda, Y., 2012. Long- term survival of salivary streptococci on dental devices made of ethylene vinyl acetate. Int. J. Oral Sci. 4, 14–18. https://doi.org/10.1038/ijos.2012.13 Park, J.B., Shaull, K.L., Overton, B., Donly, K.J., 1994. Improving mouth guards. J. Prosthet. Dent. 72, 373–380. Patrick, D.G., Van Noort, R., Found, M.S., 2005. Scale of protection and the various types of sports mouthguard. Br. J. Sports Med. 39, 278–281. https://doi.org/10.1136/bjsm.2004.012658 Perunski, S., Lang, B., Pohl, Y., Filippi, A., 2005. Level of information concerning dental injuries and their prevention in Swiss basketball – a survey among players and coaches. Dent Traumatol2 21, 195–200. Petti, S., Glendor, U., Andersson, L., 2018. World traumatic dental injury prevalence and incidence, a meta-analysis—One billion living people have had traumatic dental injuries. Dent. Traumatol. 34, 71–86. https://doi.org/10.1111/edt.12389 Pieter, W., Zemper, E.D., 1999. Head and neck injuries in young taekwondo athletes. J. Sports Med. Phys. Fitness 39, 147–53. Quaranta, A., De Giglio, O., Trerotoli, P., Vaccaro, S., Napoli, C., Montagna, M.T., Caggiano, G., 2016. Knowledge, attitudes, and behavior concerning dental trauma among parents of children attending primary school. Ann. di Ig. 28, 450–459. https://doi.org/10.7416/ai.2016.2127 Quarrie, K.L., Gianotti, S.M., Chalmers, D.J., Hopkins, W.G., 2005. An evaluation of mouthguard requirements and dental injuries in New Zealand rugby union. Br. J. Sports Med. 39, 650–654. https://doi.org/10.1136/bjsm.2004.016022 Qudeimat, M.A., AlHasan, A.A., AlHasan, M.A., Al-Khayat, K., Andersson, L., 2019. Prevalence and severity of traumatic dental injuries among young amateur soccer players: A screening investigation. Dent. Traumatol. 35, 268–275. https://doi.org/10.1111/edt.12470 Ramos-Jorge, M.L., Peres, M.A., Traebert, J., Ghisi, C.Z., De Paiva, S.M., Pordeus, I.A., Marques, L.S., 2008. Incidence of dental trauma among adolescents: A prospective cohort study. Dent. Traumatol. 24, 159–163. https://doi.org/10.1111/j.1600-9657.2007.00533.x Razeghi, S., Mohebbi, S.Z., Gholami, M., Mashayekhi, M., Maraghehpour, B., Rahnama, E., 2019. Effect of two educational interventions on primary school teachers’ knowledge and self-reported practice regarding emergency management of traumatic dental injuries. BMC Oral Health 19, 1–8. 168
https://doi.org/10.1186/s12903-019-0823-4 Razzak, A., Messahel, A., 2019. The use of mouthguards in grappling sports: a survey of grapplers in the United Kingdom. Br. Dent. J. 227, 901–905. https://doi.org/10.1038/s41415-019-0942-y Rodd, H.D., Chesham, D.J., 1997. Sports-related oral injury and mouthguard use among Sheffield school children. Community Dent. Health 14, 25–30. Salam, S., Caldwell, S., 2008. Mouthguards and orthodontic patients. J. Orthod. 35, 270–275. https://doi.org/10.1179/14653120722779 Sane, J., 1988. Comparison of maxillofacial and dental injuries in four contact team sports: American football, bandy, basketball, and handball. Am. J. Sports Med. 16, 647–651. https://doi.org/10.1177/036354658801600616 Scott, J., Burke, F.J., Watts, D.C., 1994. A review of dental injuries and the use of mouthguards in contact team sports. Br. Dent. J. 176, 310–314. Sgan-Cohen, H.D., Megnagi, G., Jacobi, Y., 2005. Dental trauma and its association with anatomic, behavioral, and social variables among fifth and sixth grade schoolchildren in Jerusalem. Community Dent. Oral Epidemiol. 33, 174–180. https://doi.org/10.1111/j.1600-0528.2005.00202.x Sigurdsson, A., 2013. Evidence-based review of prevention of dental injuries. Pediatr. Dent. 39, 184–190. https://doi.org/10.1016/j.joen.2012.11.035 Sigurdsson, A., Cohenca, N., 2018. Prevention of Dental and Oral Injuries, in: Andreasen, J.O., Andreasen, F.M., Andersson, L. (Eds.), Textbook and Color Atlas of Traumatic Injuries to the Teeth. John Wiley and Sons Ltd, Hoboken, USA, pp. 933–954. Silva-Oliveira, F., Goursand, D., Ferreira, R.C., Paiva, P.C.P., Paiva, H.N., Ferreira, E.F., Zarzar, P.M., 2018. Traumatic dental injuries in Brazilian children and oral health-related quality of life. Dent. Traumatol. 34, 28–35. https://doi.org/10.1111/edt.12358 Stewart, C., Kinirons, M., Delaney, P., 2011. Clinical audit of children with permanent tooth injuries treated at a dental hospital in Ireland. Eur. Arch. Paediatr. Dent. 12, 41–45. https://doi.org/10.1007/BF03262778 Suzuki, H., Harashima, T., Asano, T., Komiyama, O., Kuroki, T., Kusaka, K., Kawara, M., 2007. Use of Polyolefin as Mouthguard Material as Compared to Ethylene Vinyl Acetate. Int. J. Oral-Medical Sci. https://doi.org/10.5466/ijoms.6.14 Takahashi, M., Araie, Y., 2017. Mouthguard Thermoforming of Utilizing Characteristic of Elastomer. Austin Dent. Sci. 2, 2–5. Takahashi, M., Araie, Y., Satoh, Y., Iwasaki, S.-I.I., 2017. Shape change in mouthguard sheets during thermoforming - part 2: effect of the anteroposterior position of the model on mouthguard thickness. Dent. Traumatol. 33, 114–120. https://doi.org/10.1111/edt.12319 Takahashi, M., Bando, Y., 2019a. Thermoforming technique for maintaining the thickness of single-layer mouthguard during pressure formation. Dent. Traumatol. 35, 285–290. https://doi.org/10.1111/edt.12472 Takahashi, M., Bando, Y., 2019b. Thermoforming method to effectively maintain mouthguard thickness : Effect of moving the model position just before vacuum 169
formation 121–127. https://doi.org/10.1111/edt.12447 Takahashi, M., Koide, K., 2016. Variation in mouthguard thickness according to heating conditions during fabrication Part 2: Sheet shape and effect of thermal shrinkage. Dent. Traumatol. 32, 185–191. https://doi.org/10.1111/edt.12209 Takahashi, M., Koide, K., Mizuhashi, F., 2015. Variation in mouthguard thickness due to different heating conditions during fabrication: Part 2. Dent. Traumatol. 31, 18– 23. https://doi.org/10.1111/edt.12122 Takahashi, M., Koide, K., Mizuhashi, F., 2014a. Influence of sheet material shape on the thickness and fit of mouthguards. Dent. Traumatol. 30, 455–460. https://doi.org/10.1111/edt.12112 Takahashi, M., Koide, K., Mizuhashi, F., 2014b. Optimal heating conditions for forming a mouthguard using a circle tray: Effect of different conditions on the thickness and fit of formed mouthguards. J. Prosthodont. Res. 58, 171–176. https://doi.org/10.1016/j.jpor.2014.03.005 Takahashi, M., Koide, K., Mizuhashi, F., 2014c. Differences in the thickness of mouthguards fabricated from ethylene vinyl acetate copolymer sheets with differently arranged v-shaped grooves: Part 2 - effect of shape on the working model. Dent. Traumatol. 30, 472–476. https://doi.org/10.1111/edt.12123 Takahashi, M., Koide, K., Mizuhashi, F., 2013. Difference in the thickness of mouthguards fabricated from ethylene-vinyl acetate co-polymer sheets with differently arranged v-shaped grooves. J. Prosthodont. Res. 57, 169–178. https://doi.org/10.1016/j.jpor.2013.01.004 Takahashi, M., Koide, K., Mizuhashi, F., 2012. Influence of color difference of mouthguard sheet on thickness after forming. J. Prosthodont. Res. 56, 194–203. https://doi.org/10.1016/j.jpor.2011.11.002 Takahashi, M., Koide, K., Satoh, Y., Iwasaki, S.-I. ichi, 2016a. Shape change in mouthguard sheets during thermoforming. Dent. Traumatol. 32, 379–384. https://doi.org/10.1111/edt.12261 Takahashi, M., Koide, K., Suzuki, H., Iwasaki, S.I., 2016b. Optimal heating condition of ethylene-vinyl acetate co-polymer mouthguard sheet in vacuum-pressure formation. Dent. Traumatol. 32, 311–315. https://doi.org/10.1111/edt.12248 Takeda, T., Ishigami, K., Handa, J., Naitoh, K., Kurokawa, K., Shibusawa, M., Nakajima, K., Kawamura, S., 2006. Does hard insertion and space improve shock absorption ability of mouthguard? Dent. Traumatol. 22, 77–82. https://doi.org/10.1111/j.1600-9657.2006.00361.x Takeda, T., Ishigami, K., Hoshina, S., Ogawa, T., Handa, J., Nakajima, K., Shimada, A., Nakajima, T., Regner, C.W., 2005. Can mouthguards prevent mandibular bone fractures and concussions? A laboratory study with an artificial skull model. Dent. Traumatol. 21, 134–140. https://doi.org/10.1111/j.1600-9657.2005.00320.x Takeda, T., Ishigami, K., Nakajima, K., Naitoh, K., Kurokawa, K., Handa, J., Shomura, M., Regner, C.W., 2008. Are all mouthguards the same and safe to use? Part 2. The influence of anterior occlusion against a direct impact on maxillary incisors. Dent. Traumatol. 24, 360–365. https://doi.org/10.1111/j.1600-9657.2008.00576.x Takeda, T., Ishigami, K., Ogawa, T., Nakajima, K., Shibusawa, M., Shimada, A., Regner, C.W., 2004a. Are all mouthguards the same and safe to use? The
170
influence of occlusal supporting mouthguards in decreasing bone distortion and fractures. Dent. Traumatol. 20, 150–156. https://doi.org/10.1111/j.1600- 4469.2004.00247.x Takeda, T., Ishigami, K., Shintaro, K., Nakajima, K., Shimada, A., Regner, C.W., 2004b. The influence of impact object characteristics on impact force and force absorption by mouthguard material. Dent. Traumatol. 20, 12–20. https://doi.org/10.1111/j.1600-4469.2004.00210.x Takeda, T., Kajima, T., Nakajima, K., Narimatsu, K., Konno, M., Hasegawa, K., Sekiguchi, C., Ozawa, T., Noh, K., Ishigami, K., 2014. Paired maxillary and smaller mandibular mouthguard for rugby player with malalignment. Dent. Traumatol. 30, 76–80. https://doi.org/10.1111/edt.12050 Tanaka, Y., Maeda, Y., Yang, T.-C.C., Ando, T., Tauchi, Y., Miyanaga, H., 2015. Prevention of orofacial injury via the use of mouthguards among young male rugby players. Int. J. Sports Med. 36, 254–261. https://doi.org/10.1055/s-0034- 1390498 Tewari, N., Goel, S., Rahul, M., Mathur, V.P., Ritwik, P., Haldar, P., Priya, H., Pandey, R.M., 2020. Global status of knowledge for prevention and emergency management of traumatic dental injuries among school teachers: A systematic review and meta‐analysis. Dent. Traumatol. 1–16. https://doi.org/10.1111/edt.12579 The International Hockey Federation, 2018. Rules of Hockey Including Explanations. Lausanne, Switzerland. Tribst, J.P.M., de Oliveira Dal Piva, A.M., Borges, A.L.S., Bottino, M.A., 2018. Influence of custom-made and stock mouthguard thickness on biomechanical response to a simulated impact. Dent. Traumatol. 34, 429–437. https://doi.org/10.1111/edt.12432 Tulunoglu, I., Özbek, M., 2006. Oral trauma, mouthguard awareness, and use in two contact sports in Turkey. Dent. Traumatol. 22, 242–246. https://doi.org/10.1111/j.1600-9657.2006.00386.x Tunc, E. Sen, Ozdemir, T.E., Arici, S., 2013. Postfabrication thickness of single- and double-layered pressure-formed mouthguards. Dent. Traumatol. 29, 378–382. https://doi.org/10.1111/edt.12010 U.S. Bureau of Labor Statistics, 2020. CPI Inflation Calculator. Last accessed 13 July 2020.
171
dynamic finite element impact study. Dent. Traumatol. 32, 95–102. https://doi.org/10.1111/edt.12210 Vucic, S., Drost, R.W., Ongkosuwito, E.M., Wolvius, E.B., 2016a. Dentofacial trauma and players’ attitude towards mouthguard use in field hockey: a systematic review and meta-analysis. Br. J. Sports Med. 50, 298–304. https://doi.org/10.1136/bjsports-2015-094896 Vucic, S., Drost, R.W., van Wijk, A.J., Wesselink, P.R., Wolvius, E.B., 2016b. Patterns of orodental injury and mouthguard use in Dutch field hockey. Br. J. Sports Med. 50, 661–668. https://doi.org/10.1136/bjsports-2015-095677 Waked, E.J., Lee, T.K., Caputo, A.A., 2002. Effects of aging on the dimensional stability of custom-made mouthguards. Quintessence Int. (Berl). 33, 700–705. Walker, J., Jakobsen, J., Brown, S., 2002. Attitudes concerning mouthguard use in 7- to 8-year-old children. J. Dent. Child. 69, 207–211. Westerman, B., Stringfellow, P.M., Eccleston, J.A., 2002a. EVA mouthguards: How thick should they be? Dent. Traumatol. 18, 24–27. https://doi.org/10.1034/j.1600- 9657.2002.180103.x Westerman, B., Stringfellow, P.M., Eccleston, J.A., 2002b. Beneficial effects of air inclusions on the performance of ethylene vinyl acetate (EVA) mouthguard material. Br. J. Sports Med. 36, 51–53. https://doi.org/10.1136/bjsm.36.1.51 Westerman, B., Stringfellow, P.M., Eccleston, J.A., 1997. An improved mouthguard material. Aust. Dent. J. 42, 189–191. https://doi.org/10.1111/j.1834- 7819.1997.tb00120.x Westerman, B., Stringfellow, P.M., Eccleston, J.A., Harbrow, D.J., 2002c. Effect of ethylene vinyl acetate (EVA) closed cell foam on transmitted forces in mouthguard material. Br. J. Sports Med. 36, 205–208. https://doi.org/10.1136/bjsm.36.3.205 Whelton, H., O’Mullane, D., Harding, M., Guiney, H., Cronin, M., Flannery, E., Kelleher, V., 2006. North South survey of children’s oral health in Ireland 2002. Dublin, Ireland. World Rugby, 2020. Laws of the Game - Rugby Union. Last accessed 13 July 2020
8. https://doi.org/10.1371/journal.pone.0074833 Zamora-Olave, C., Willaert, E., Montero-Blesa, A., Riera-Punet, N., Martinez-Gomis, J., 2018. Risk of orofacial injuries and mouthguard use in water polo players. Dent. Traumatol. 34, 406–412. https://doi.org/10.1111/edt.12434 Zaror, C., Martínez-Zapata, M.J., Abarca, J., Díaz, J., Pardo, Y., Pont, À., Ferrer, M., 2018. Impact of traumatic dental injuries on quality of life in preschoolers and schoolchildren: A systematic review and meta-analysis. Community Dent. Oral Epidemiol. 46, 88–101. https://doi.org/10.1111/cdoe.12333
173
6 Appendices
6.1 Appendix 1: Letter of Ethical Approval
Dr Elaine Shore C/O Division of Public & Child Dental Health, Dublin Dental University Hospital, Lincoln Place, Dublin 2, D02 F859
2nd November 2018
Ref: 180901
Title of Study: An investigation into player compliance and level of protection afforded by mouthguards worn by children playing sport in Ireland.
Dear Dr Shore,
Further to a meeting of the Faculty of Health Sciences Ethics Committee held in September 2018. We are pleased to inform you that the above project has ethical approval to proceed.
As a researcher you must ensure that you comply with other relevant regulations, including DATA PROTECTION and HEALTH AND SAFETY.
Yours sincerely,
Prof. Brian O’Connell Chairperson Faculty Research Ethics Committee
174
6.2 Appendix 2: Letter of invitation to GAA & LGFA
Division of Public and Child Dental Health Dublin Dental University Hospital Lincoln Place Dublin 2 Dear Sir/Madam
The GAA/LGFA have been extremely proactive in requiring mouthguards to be worn by Gaelic football players of all levels for training and matches since 2014. It is my understanding that this has resulted in a significant reduction in dental injury related insurance claims.
Traumatic Dental Injury is a major topic of research within the Dublin Dental University Hospital, Trinity College Dublin. As a postgraduate student, I wish to complete my thesis on the use of mouthguards to prevent sports-related dental injuries. The title of my research study is “An investigation into player compliance and level of protection afforded by mouthguards worn by children playing sport in Ireland”. I am writing to seek your support and permission to conduct this research study among children aged 9 to 16 years old playing Gaelic football in Ireland.
Gaelic football is my sport of choice since the culture of injury prevention and player safety fostered by the mouthguard initiative reflects very positively on the LGFA & GAA. The over- arching aim of this piece of research is to reduce sports-related dental trauma among children in Ireland as a whole, by encouraging other sporting organisations to follow the lead of the Gaelic Football in introducing mandatory mouthguard rules for all players.
My research project has been approved and will be supervised by Staff of Trinity College Dublin. Ethical approval has been obtained from the Faculty of Health Sciences Research Ethics Committee at Trinity College Dublin.
I have included with this letter a brief outline on what the study will entail for young sportspersons and their parents. It is my hope that your organisation would endorse this study and facilitate access to individual clubs.
This study is the first of its kind to be conducted in Ireland and will contribute valuable evidence to the field of dental trauma prevention. I believe that this study should help to strengthen and publicise the effectiveness of the GAA mouthguard rule in reducing the incidence of dental injuries.
I and my supervisor, Dr. Anne O’Connell, would be glad of the opportunity to discuss this further to address any queries you may have. Please feel free to contact me at [email protected] or via phone call with our divisional office at 01-6127303 to arrange a meeting at a time that is convenient to you.
Thank you very much for taking the time to consider this proposal.
Yours sincerely,
Dr. Elaine Shore B.A., B.Dent.Sc, MFDS (RCSI) D.Ch.Dent. (Paediatric Dentistry) candidate
175
176
6.3 Appendix 3: Letter of Approval from GAA
GAA GAA P áirc an Chrócaigh Croke Park Baile Átha Cliath 3 Dublin 3 Guthán +353 1 836 3222 Telephone +353 1 836 3222 Faics +353 1 836 5075 Fax +353 1 836 5075 www.gaa.ie www.gaa.ie
A chara,
The GAA’s Medical, Scientific and Welfare Committee would like to extend our support to Elaine Shore for her Mouthguard Study
If you require any further clarification, please do not hesitate to contact me.
Is mise le fíor mheas
Breandáin Ó Chonghaile Rúnaí (Coiste Leighis, Leasa agus Eolaíochta) 4ú Feabhra 2019 01-8658610.
177
6.4 Appendix 4: LGFA Letter of Approval
14th March 2019
A chara,
The Ladies Gaelic Football Association would like to extend our support to Elaine Shore for her Mouthguard Study.
If you require any further clarification, please do not hesitate to contact me.
Regards
______Paula Prunty Operations & Planning Manager
178
6.5 Appendix 5: Letter of Invitation to Individual GAA Clubs
Division of Public and Child Dental Health Dublin Dental University Hospital Lincoln Place Dublin 2
Dear Sir/Madam,
My name is Elaine Shore, and I am a postgraduate student undertaking a clinical doctorate programme in Paediatric Dentistry at the Dublin Dental University Hospital, Trinity College Dublin. My area of interest is in dental trauma, specifically in the use of mouthguards to prevent sports-related dental injuries.
I wish to invite your club to participate in my research study, entitled “An investigation into player compliance and level of protection afforded by mouthguards worn by children playing sport in Ireland”.
The GAA have been extremely proactive in requiring mouthguards to be worn by Gaelic football players of all levels for training and matches since 2014. It is my understanding that this has resulted in a significant reduction in dental injury related insurance claims.
The GAA is the organisation of choice for this study since the culture of injury prevention and player safety fostered by this mouthguard initiative reflects very positively on your organisation. The over-arching aim is to reduce sports-related dental trauma among children in Ireland as a whole, by encouraging other sporting organisations to follow the lead of the GAA in introducing mandatory mouthguard rules for all players.
Ethical approval for this study has been obtained from the Faculty of Health Sciences Research Ethics Committee at Trinity College Dublin.
With your permission, we would seek parent/guardian permission on written informed consent forms to allow their children to participate in the study. I plan to survey parents and children in relation to their knowledge and attitudes regarding the use of mouthguards in sport. Along with a team of dentists, I would like to attend your club at a suitable time to examine the teeth and mouthguards of children between the ages of 9 and 16 years (under-12 up to under-16 age categories). Specifically, we will be checking their permanent teeth for signs of dental trauma. We will assess their mouthguards to see which type they are wearing, and if they cover the teeth and bone sufficiently. We will then measure the thickness of each mouthguard.
With due consideration to child protection, we would only conduct these examinations in an open area within the GAA club premises, in the presence of other responsible adults, and preferably under the supervision of an adult representative from your club.
179
The data collected will be pseudo-anonymised using a coded system to ensure that parents and children are not identifiable from their records. Records will be securely and safely stored in a restricted-access area of the Dublin Dental Hospital for the duration of the study.
With parent/guardian permission, we may take some clinical photographs to illustrate the mouthguards worn; the images will be of the mouth, teeth and mouthguards only – we will have no need to take any full-face photographs of any child and will not be retaining any identifier on these photographs. These images will be taken on a DSLR camera and will be stored on a password protected computer hard drive.
The benefit of this process to each child is that it is an opportunity for them to have a free- of-charge mouthguard check by qualified experienced dentists. If necessary, recommendations for new mouthguards will be made.
Please note, this will not be a full dental examination or check-up, and we will not actively be looking for signs of dental disease. However, if any issues are noted as an incidental finding, we will recommend that they see their usual family dentist for a check-up.
All examiners are qualified dentists from the Dublin Dental University Hospital (DDUH), and we have all completed Children’s First child protection training in March 2018. We have all obtained Garda clearance in order to work at the DDUH; we are also covered under that hospital’s Clinical Indemnity Scheme. The Gaelic Athletic Association in Croke Park have been contacted and have offered their support and endorsement for this initiative.
I am enclosing a pack containing the parent/guardian invitation letter and study information leaflet, the parent/guardian survey, the consent form, the child information leaflet and survey form, the examination record, and the information sheet to be given to the children following their mouthguard examination.
I am hopeful that you will be happy to accept our invitation to participate in this study, as I feel that this piece of research will be influential in raising awareness in relation to mouthguards even further and preventing even more dental trauma among young people in Ireland.
Thank you most sincerely for taking the time to consider this proposal. I am very happy to answer any queries that you may have; please feel free to contact me at [email protected] or via phone call with our divisional office at 01-6127303.
I look forward to hearing from you.
Yours faithfully,
Dr. Elaine Shore B.A., B.Dent.Sc. M.F.D.S. (RCSI) Postgraduate Student D.Ch.Dent. (Paediatric Dentistry)
180
6.6 Appendix 6: Participant Information Leaflet – Parent
Participant Information Leaflet
Title of study: An investigation into player compliance and level of protection afforded by mouthguards worn by children playing sport in Ireland.
I would like to invite you take part in a research study. Before you decide, you need to understand why the research is being done and what it would involve for you. Please take time to read the following information carefully. Ask questions if anything you read is not clear or if you would like more information. Take time to decide whether or not to take part.
WHO I AM AND WHAT THIS STUDY IS ABOUT
I am a clinical doctoral candidate in Paediatric Dentistry at the School of Dental Science, Trinity College Dublin. This research study relates to dental trauma, specifically the prevention of sports-related dental injuries.
Sports-related injuries to the teeth and the face can be severe. They are usually associated with significant pain and distress and require lifelong dental treatment and follow-up, which can be expensive. They often involve the upper front teeth, and occasionally these teeth are lost. This has significant detrimental psychological implications for the child. Such injuries may be prevented by wearing mouthguards. The GAA have been very proactive in implementing mandatory mouthguard rules for Gaelic football players of all levels for training and matches since 2014. This reduces the risk of dental trauma by protecting the teeth from injury.
This study aims to investigate player compliance with GAA mouthguard rules, and types of mouthguards worn in training sessions and matches. We will also investigate the opinions of children and parents around the wearing of mouthguards and dental trauma. The overall aim is to reduce sports-related dental trauma among children in Ireland by encouraging other sporting organisations to follow the lead of the GAA in introducing mouthguard rules.
WHAT WILL TAKING PART INVOLVE?
My team and I will attend your child’s club at a time agreed upon with your club. We will ask you and your child some questions about how you feel about mouthguards in general. We will look at the children’s teeth for signs of previous injuries. We will check their mouthguards to see which type they are wearing, and if it fits the teeth properly. We will then measure the thickness of each mouthguard.
This examination will take place in an open area at the GAA club in the presence of you or another responsible adult, as child safety is always a priority. We are all qualified, vetted and indemnified.
181
WHY HAVE YOU BEEN INVITED TO TAKE PART?
Your child’s GAA club have kindly allowed us to attend one of your child’s team’s training sessions to examined mouthguards. We are examining children between the ages of 9 and 16 years playing Gaelic football. All children on the team have received the same information pack and participant information leaflet.
DO YOU HAVE TO TAKE PART?
Participation in this research study is entirely voluntary and you and your child are under no obligations to take part. Your child’s participation in this study is not contingent on any conditions and, should you decide not to take part, this will not have any effect on their position within the GAA.
If you decide to take part in this study, you have the right to withdraw you & your child’s participation at any time. You will not be penalised in any way, and you and your child will not lose any benefits you had prior to the study.
WHAT ARE THE BENEFITS OF TAKING PART?
The benefit of participating in this study for your child is that it is an opportunity for them to have their mouthguards checked by experienced dentists, free of charge. We will be able to identify mouthguards that are not likely to be protecting the teeth properly. In this case, we will be able to advise that they get a new mouthguard to prevent injuries to their teeth while playing sports.
ARE THERE ANY RISKS OF TAKING PART?
The potential risks of taking part in this study are limited. Because we are simply looking at your child’s mouthguard, we are not providing any intervention so the study is purely observational in nature.
WILL TAKING PART BE CONFIDENTIAL?
Your identity & your child’s identity will remain confidential for all aspects relating to this study. All data collected will be coded so no personal information can be traced back to you or your child. This means that a random number will be assigned to all questionnaires, data sheets and photographs taken of teeth or mouthguards. This number will be used to identify and analyse data collected during the study. Your name & your child’s name will never be attached to coded data and will never be published. Your signed consent forms will not be linked to your unique identifier number; these will be stored completely separately to all research data, and only serve as a record of your consent to participate in the study. Statistical analysis of the data will be carried out by a statistician; however, they will have no access to any personal identifiers at any time.
HOW WILL THE INFORMATION YOU PROVIDE BE STORED AND PROTECTED?
All hard copy records (examination sheets, consent forms) will be stored in a locked cupboard in a swipe-access controlled room in the Dublin Dental University Hospital, with the keys being held by only the lead investigator. These records will be kept for a period of 5 years and will then be destroyed. Any electronic forms of data will be stored
182
in a password-protected file on an encrypted hard drive, with access limited to the lead investigator only.
WHAT WILL HAPPEN TO THE RESULTS OF THE STUDY?
The results of this study will be analysed and published in a doctoral thesis which will be submitted to Trinity College Dublin. The results will also be published in articles in a peer-reviewed international dental journal and will be presented at international dental conferences. These results will be used for educational and teaching purposes.
WHAT DO I NEED TO DO TO TAKE PART IN THIS STUDY?
You can contact the research team directly at [email protected] or 01- 6127303 to express your interest in taking part, or alternatively you may enrol for the study by personally approaching the research team directly on the day when they attend your child’s club.
If you have any queries in relation to any aspect of this study prior to consenting to your child’s participation, I will be happy to answer them – please feel free to contact me via email at [email protected] or by phone at 01-6127303.
Thank you for taking the time to consider participating in this study.
Yours faithfully,
Dr. Elaine Shore B.A., B.Dent.Sc., MFDS (RCSI) D.Ch.Dent. (Paediatric Dentistry) candidate
183
6.7 Appendix 7: Participant Information Leaflet – Child
Participant Information Leaflet
Title of study: An investigation into player compliance and level of protection afforded by mouthguards worn by children playing sport in Ireland.
Dear Footballer,
I would like to invite you take part in a research project. Please take time to read the following information carefully, and if you have any questions please ask!
WHO I AM AND WHAT THIS STUDY IS ABOUT
I’m a dentist in the Dublin Dental University Hospital, working in the Paediatric department. I want to check how many Gaelic football players wear their mouthguard and which types of mouthguards they are wearing. I also want to make sure that the mouthguards fit OK. I also want to find out what you and your parents think about mouthguards. What I am really hoping to do is to reduce the number of teeth being damaged in sports accidents in Ireland.
WHAT WILL TAKING PART INVOLVE?
Your club have said that I can come and visit on
Here’s what we’re going to do:
1. We’ll ask to see your mouthguard 2. We’ll ask you to put it in your mouth 3. We’re going to have a quick look at the mouthguard when it’s in your mouth to make sure that it’s covering your teeth and gums properly 4. Then we’ll take out your mouthguard and have a very quick look at your teeth to see if they’ve had any accidents before 5. We’ll check your mouthguard to see if there are any holes in it, and make sure it’s thick enough. Then we’ll have a little chat afterwards and we’ll ask you some easy questions to find out what you think about your mouthguard.
Everything will take about 5-10 minutes. We just want to look at your mouthguards and see if they’re minding your teeth properly, so we’ll be very quick!
WHY HAVE YOU BEEN INVITED TO TAKE PART?
Your GAA club have kindly said we can come to one of your team’s training sessions to check mouthguards. We are examining children between the ages of 9 and 16 years playing Gaelic football. Everyone on your team has been invited and has received the same information pack.
184
DO YOU HAVE TO TAKE PART?
You don’t have to be a part of this project if you don’t want to, and if you decide not to take part this won’t affect your participation within your football team. You can pull out of this project at any time if you decide that you don’t want to take part anymore.
WHAT DO YOU NEED TO DO TO TAKE PART IN THIS STUDY?
Your parent/guardian will contact us if you’re happy to take part.
I’m really looking forward to meeting you properly on
Yours faithfully,
Dr. Elaine Shore B.A., B.Dent.Sc., MFDS (RCSI) D.Ch.Dent. (Paediatric Dentistry) candidate
185
6.8 Appendix 8: Consent Form – Parent
Mouthguard Study - Consent Form for Parent
Thank you for taking the time to consider our invitation to participate in our mouthguard study.
The parent survey will be in the form of a questionnaire.
There are 17 questions, largely in the form of a multiple-choice questions and questions needing very short answers.
I’m aiming to find out how you as a parent feels about the use of mouthguards by your child while they are playing sports.
Data Protection
Any data collected relating to you or your child will be safe. No personal data will be collected. It will be securely stored and coded so that you and your child will not be identifiable by it.
If you prefer not to participate, this will not have any ramifications for your child’s position within the GAA. We have no affiliations with the GAA.
Consent
Please sign below:
I have read the above information and the Parent Invitation Letter.
Agree Disagree Signature
I consent to participate in the parent survey component of this study
Print Name: ______Date: ______
186
6.9 Appendix 9: Consent Form – Child Participation
Mouthguard Study - Consent Form for Child
Thank you for taking the time to consider our invitation to participate in our mouthguard study.
The mouthguard examination will be carried out by a qualified dentist and will take place in an open area at the GAA club as agreed with the Club Child Protection and Safety officers.
The examination will involve:
1. Checking your child’s teeth for signs of dental trauma (broken, missing, or discoloured front teeth; white fillings on front teeth); 2. Establishing the type of mouthguard worn by your child; 3. Checking the fit of this mouthguard in your child’s mouth; 4. Checking to make sure it is covering the teeth and gums properly to protect your child’s teeth in the event of a sport-related accident; 5. Checking the thickness of the mouthguard; 6. Finding out what children think about mouthguards. Please note: the mouthguard examination is not a full dental check-up.
• Our aim is to make sure that the mouthguards are all offering the proper protection so that your child’s teeth are safe and sound while they enjoy their sport. • If we notice dental issues during the mouthguard check, we will advise that your child needs to see a family dentist for a full check-up. Data Protection
Any data collected relating to you or your child will be safe. No personal data will be collected. It will be securely stored and coded so that you and your child will not be identifiable by it.
If you prefer that your child does not participate, this will not have any ramifications for their position within the GAA. We have no affiliations with the GAA.
187
Consent
Please sign in 3 places:
I have read the above information and the Parent Invitation Letter.
Agree Disagree Signature
I give my child ______permission to participate in this study: to have their teeth examined, and to answer questions posed by the dentist
I consent for my child’s teeth, mouth, or mouthguard to be photographed and for the resulting images to be used anonymously for research and publication purposes
I give consent for my child to be examined at their GAA club in the presence of a responsible adult representative from the GAA club
Print Name: ______Date: ______
188
6.10 Appendix 10: Parent Questionnaire
Mouthguard Study - Parent Questionnaire
1. How many of your children play sports?
2. What ages are they? With regard to this child:
3. Which sports do they play? (Tick as appropriate)
Gaelic Football Tennis Any other: Please specify Hurling/Camogie Basketball Soccer Badminton Rugby Volleyball Hockey Boxing/Martial Arts
4. Do they wear a mouthguard? Yes No
If yes, do they wear mouthguards for all sports, or some sports? All Some (please specify which sports) ______
5. Does every sport require them to wear a mouthguard? Yes No If no, please specify which sports do require a mouthguard.
6. Which type of mouthguard do they wear? Shop bought, ready to wear Shop bought, boil & bite Made by dentist
7. In your opinion, which types of mouthguard will protect teeth properly? Shop bought, ready to wear Shop bought, boil & bite Made by dentist
8. How old is their mouthguard?
189
9. Where is their mouthguard kept when not in their mouth? In gear bag In mouthguard box Other
10. How is their mouthguard cleaned?
11. How often is it cleaned?
12. Do they wear it for: Training only Match only Training and matches Don’t wear them?
13. Has your child ever had a dental injury to their permanent (adult) teeth? Yes No
14. Was it while playing sports? Yes No
15. What type of injury was it? Tooth broke Tooth fell out completely Note: if there Tooth was loosened Tooth was pulled forwards was more than Tooth pulled out of gum, but not all Tooth was pushed one injury, the way out backwards please select Tooth was pushed up into gum Don’t know / Not sure multiple answers
16. Were they wearing a mouthguard at the time? Yes No
17. How much would you be willing to pay for a mouthguard specially made to fit your child’s teeth?
Please share any further comments you think we should know:
Thank you most kindly for participating in this research project. Your help is very much appreciated.
190
6.11 Appendix 11: Child Questionnaire
CODE:
Child Questionnaire
(To be completed by examiner – asking questions and filling in child’s answers)
1. What age are you?
2. What sports do you play?
3. Do you wear your mouthguard for all of them? Yes No
If no, which ones do you WEAR mouthguards for?
And why don’t you wear mouthguards for the others?
4. Which sports make you wear mouthguards?
5. Do you wear your mouthguard for training in Gaelic football? Yes No 6. Do you wear it for Gaelic football matches? Yes No 7. Do you like your mouthguard? Yes No If no, why not?
8. Can you talk when you’re wearing it? Yes No 9. Can you breathe properly when you’re wearing it? Yes No
191
10. Does it taste ok? Yes No
11. Did you pick it or did someone else pick it? I picked it Someone else picked it If someone else, who?
12. When did you get this mouthguard?
13. Where do you keep it when you’re not wearing it?
14. Do you clean it? Yes No 15. How?
16. When?
17. Did you ever have an accident that hurt your teeth? Yes No 18. Were you playing sports? Yes No 19. What age were you? (approximately)
20. Were you wearing your mouthguard? Yes No 21. Do you think there’s anything you’d like us to know especially about your mouthguard?
192
6.12 Appendix 12: Dentist Examination Sheet
Dentist Examination Sheet 1. Child age ______
Male Female
2. Dentition (circle as appropriate): Primary / Mixed / Permanent
3. Signs of trauma Yes / No If yes: Class IV composite Fractured tooth Discoloured tooth o Enamel Loose tooth o Enamel-dentine Missing tooth o Enamel-dentine-pulp o Crown-root If missing tooth Replacement with: ______No replacement
4. Overjet: (circle as appropriate) Reduced / Normal / Increased / Anterior Open Bite
5. Mouthguard present Y / N
6. Mouthguard type Stock Mouth-formed Custom made
7. Mouthguard surface intact Y / N 8. Smooth contoured borders Y / N 9. Mouthguard colour? Light / Dark / Transparent 10. Obvious deformations? Y / N Adequate Inadequate Occlusal coverage
Retention Labial extension Palatal extension Balanced occlusion
11. Labial thickness (to 0.1 mm) 13 11 21 23
12. Occlusal thickness (to 0.1 mm) 16 (DB cusp) 13 11 21 23 26 (DB cusp)
13. Any other comments?
193
6.13 Appendix 13: Mouthguard Photographs
1. Stock MG – not fitting teeth; not covering labial surface of teeth; poor retention – need to bite to keep in place.
2. Mouth formed MG. Bulky with ramp posteriorly. Unable to close lips.
3. Stock MG: Surface roughness, poor hygiene
4. Stock MG; Not fitting dentition; insufficient labial extension, poor retention, obvious deformation on right side, sharp borders with labial gingival blanching at tooth 22
194
5. Well adapted mouth-formed MG
6. Mouth formed MG – not adapted to fit teeth; surface integrity compromised - separation of layers; poor hygiene
7. Mouth-formed MG – not adapted to teeth; not fitting dentition, not covering anterior teeth; poor retention and unable to close lips while in situ.
195