J Oral Maxillofac Surg 71:14-22, 2013 Oral Tori Are Associated With Local Mechanical and Systemic Factors: A Case- Control Study Matthew Daniel Morrison, DMD, MSc,* and Faleh Tamimi, BDS, PhD† Purpose: To estimate if various dental factors, medications, and medical conditions are associated with an increased risk for the presence of oral tori. Materials and Methods: Using a case-control study design, the investigators identified and adjudicated a sample of cases with torus palatinus (TP) and/or torus mandibularis (TM) during a 1.5-year period. The medical records were abstracted and data on dental factors, temporomandibular dysfunction (TMD), medi- cations, and medical conditions were recorded. Risk estimates were calculated as adjusted odds ratios (AORs) with 95% confidence intervals (CIs) using conditional logistic regression analyses, and the P value was set at .05. Results: The sample was composed of 66 subjects with TM, 34 subjects with TP, and 100 control subjects from the same database. Any form of oral torus (TP and/or TM) was associated significantly with TMD (AOR, 10.51; 95% CI, 4.46 to 24.78; P Ͻ .01) and tooth attrition (AOR, 5.22; 95% CI, 2.32 to 11.77; P Ͻ .01). TP was associated significantly with TMD (AOR, 4.14; 95% CI, 1.21 to 14.21; P Ͻ .05), tooth attrition (AOR, 38.18; 95% CI, 7.20 to 202.41; P Ͻ .01), and treated hypertension (AOR, 6.64; 95% CI, 1.31 to 33.57; P Ͻ .05). TM was associated significantly with TMD (AOR, 5.77; 95% CI, 2.38 to 13.98; P Ͻ .01), tooth attrition (AOR, 6.69; 95% CI, 2.78 to 16.14; P Ͻ .01), and a penicillin allergy (AOR, 4.45; 95% CI, 1.05 to 18.83; P Ͻ .05). Conclusions: This study provides clinical evidence showing significant associations between oral tori and various dental factors, medications, and medical conditions. These findings add to the list of environmental factors believed to contribute to the formation of oral tori. © 2013 American Association of Oral and Maxillofacial Surgeons J Oral Maxillofac Surg 71:14-22, 2013 The control of bone quantity and quality in the oral can produce its own ectopic oral bone, as seen environment is essential for the success of dental with oral tori, but this process is poorly under- implantation and bone and soft tissue grafting pro- stood. cedures. Much research has been dedicated to de- Two of the most common oral exostoses are the veloping new surgical techniques and materials for torus palatinus (TP) and the torus mandibularis (TM). alveolar ridge augmentation. Interestingly, the body Oral tori are benign developmental anomalies, or hamartomas, having no pathologic significance and consisting of dense cortical bone with a limited amount of bone marrow.1,2 The TP is found on the midline of the hard palate, and the TM appears on Received from the Faculty of Dentistry, McGill University, Mon- the lingual aspect of the mandible, above the my- treal, Quebec, Canada. lohyoid line, in the canine/premolar region.2 These *Research Assistant. bony outgrowths are covered by a thin and poorly †Assistant Professor. vascularized mucosa. They tend to grow slowly and This work was supported financially by NSERC, the Faculty of Dentistry at McGill University, and La Fondation de l’Ordre des continuously, but have been found to stop growing 2 Dentistes du Québec. spontaneously in the absence of teeth. Oral tori Address correspondence and reprint requests to Dr Tamimi: are usually discovered incidentally during a routine Faculty of Dentistry, McGill University, Room M60C, Strathcona clinical examination because they rarely produce 3 Anatomy and Dentistry Building, 3640 University Street, Montreal, symptoms. Quebec, Canada, H3A 2B2; e-mail: [email protected] The prevalence of oral tori has been reported to 4,5 © 2013 American Association of Oral and Maxillofacial Surgeons be 12% to 15%. A strong association has been 0278-2391/13/7101-0$36.00/0 found between the TP and the TM, whereby 50% of http://dx.doi.org/10.1016/j.joms.2012.08.005 subjects with a TM had a concurrent TP and 30% 14 MORRISON AND TAMIMI 15 of subjects with a TP also had a TM.4 The growth of eral Hospital. This study followed the Declaration of these bony lesions typically begins during puberty, Helsinki on medical protocol and ethics, and approval but may begin as late as 30 to 50 years old, and they was granted from the ethics committee of the McGill slowly enlarge into adulthood.6 The TP and TM are University Health Center, Montreal, Quebec. The generally first noticed in older subjects, at an aver- electronic dental records of the subjects were age age of 34 to 39 years old.4,5 Furthermore, the searched and the original hard copy files were re- TP has been found to appear more frequently in trieved for manual examination. The study period was women, whereas the TM is more common in from July 1, 2010, to January 30, 2012. men.4,5,7,8 Surgical removal is often not necessary for an oral CASE DEFINITION AND VALIDATION torus unless it has reached a size large enough to The authors identified subjects who had a TP interfere with speech, mastication, the construction and/or a TM as recorded in the computerized data- of a dental prosthesis, or if it is prone to traumatic base during the study period. A TP was recorded as ulceration. In cases of severe periodontal disease, the present when an asymptomatic bony outgrowth was removal of oral tori may be recommended to enhance clinically visible on the midline of the hard palate, periodontal pocket elimination and to allow better consistent with the typical presentation.2 ATMwas access for oral hygiene.1 In addition, these lesions recorded when an asymptomatic bony outgrowth may be excised for clinical crown lengthening, for was clinically visible on the lingual aspect of the site preparation before removable denture fabrica- mandible in the canine/premolar region, consistent tion, or to obtain heterogeneous bone for grafting with the typical presentation.2 Subjects were ex- purposes.9-11 cluded from the case group if the dental records did Insight into the process of ectopic oral bone not describe intra- and extraoral examinations, a full formation, as with oral tori, could assist in devel- medical history, a list of current and previous medi- oping less invasive methods for alveolar ridge aug- cations, details for any parafunctional habits, and a mentation and the natural enhancement of bone complete odontogram. quality for dental implant placement. However, an accepted mechanism for the development of oral CONTROLS tori is not known despite the high prevalence of Control subjects matched to cases by entry date, these bony outgrowths. The exact etiology of oral gender proportion, and age range were selected from tori has eluded investigators for decades, but it is the computerized database within the same study believed that the trait (TP and/or TM) is expressed period. Subjects were excluded from the control when a certain threshold of genetic and local envi- group if they had an oral torus. Furthermore, subjects ronmental factors is surpassed.4,5,8,10,12-21 Histori- were excluded if the dental records did not describe cally, studies on the etiology of these bony lesions intra- and extraoral examinations, a full medical his- have focused on genetic and environmental influ- tory, a list of current and previous medications, details ences, but have neglected to investigate the broad for any parafunctional habits, and a complete odon- scope of interdependent factors involved in bone togram. metabolism. The purpose of this investigation was to undertake a broader assessment of potential en- MEASUREMENTS vironmental influences and, in doing so, address the The following measurements were recorded: age, following question: in subjects with oral tori, are gender, hypertension, hypothyroidism, type 1 or 2 there associations with various dental factors, med- diabetes mellitus, respiratory problems (asthma and ications, and medical conditions compared with obstructive sleep apnea), periodontal disease, penicil- control subjects? The authors hypothesized that the lin allergy, anxiety/depression, smoking habit, TMD, presence of oral tori would be associated with a and signs of tooth attrition. A history of periodontal greater risk for tooth attrition, temporomandibular disease was recorded for any subject having an overall dysfunction (TMD), medical conditions, and certain periodontal screening and recording score of 3 or 4.22 pharmacologic agents compared with the absence Signs of tooth attrition were noted for clinically evi- of oral tori. To test this hypothesis, the authors dent, atypical wear patterns on incisal edges and cusp implemented a case-control study. tips, consistent with attrition resulting from parafunc- tion.23-25 Evidence of TMD was determined according to established diagnostic guidelines.26-29 These Materials and Methods signs and symptoms included uni- or bilateral click- A case-control study was conducted using subjects ing and/or crepitus of the temporomandibular attending the McGill University Undergraduate Teach- joint(s) and/or tenderness to palpation of the preau- ing Clinic, Faculty of Dentistry, at the Montreal Gen- ricular area and muscles of mastication. Typical 16 FACTORS ASSOCIATED WITH ORAL TORI Table 1. FREQUENCIES OF CHARACTERISTICS OF CASE SUBJECTS VERSUS CONTROL SUBJECTS Controls TP and/or TM TP TM Characteristics Percentage (95% CI) Percentage (95% CI) Percentage (95% CI) Percentage (95% CI) Age (yr) 53.6 (50.9-56.3) 47.2 (42.9-51.6) 44.5 (36.7-52.3) 47.3 (42.6-52.0) Men 51 (41-61) 41 (31-51) 32 (16-49) 41 (30-52) Smokers 8 (3-13) 7 (1-12) 6 (Ϫ2 to 14) 7 (2-13) Attrition 23 (15-31) 59 (49-69) 62 (45-79) 58 (47-69) TMD 14 (7-21) 44 (34-54) 44 (27-62) 47 (36-58) Periodontal disease 43 (33-53) 36 (26-46) 32 (16-49) 37 (27-48) Hypertension 21 (13-29) 23 (15-31) 26 (11-42) 22 (13-31) Penicillin allergy 5 (1-9) 8 (3-13) 3 (Ϫ3 to 9) 8 (2-15) Respiratory problem 4 (0-8) 9 (3-15) 6 (Ϫ2 to 14) 10 (3-16) Hypothyroidism 3 (0-6) 8 (3-13) 15 (2-27) 6 (1-11) Diabetes mellitus 8 (3-13) 5 (1-9) 3 (Ϫ3 to 9) 5 (0-10) Anxiety/depression 4 (0-8) 7 (2-12) 6 (Ϫ2 to 14) 7 (2-13) Abbreviations: CI, confidence interval; TM, torus mandibularis; TMD, temporomandibular dysfunction; TP, torus palatinus.