Needs for Treatment Dental and social effects of malocclusion and effectiveness of orthodontic treatnient: a review

W. C. SHAW', M. ADDY' and C. Dental School, Welsh .National School of Medicine, Heath Park and "^University College, Cardiff, United Kingdom

Shaw, W. C, Addy, M. & Ray, C: Dental and soeial eflects of malocclusion and eflectiveness of orthodontic treatment: a review. Community Dent. Oral Epidemiol. 1980: 8: 36-45.

Abstract - The relationship between malocclusion and the health of the masticatory apparatus is reviewed. While there is evidenee that eertain features stich as tratimatic deep overbite, unprotected incisors and impacted teeth may adversely alfect the longevity of the dentition, the relationship of dental irregularity to periodontal disease, caries and mandibular dysfunction is less certain. Studies in the field ol soeial psychology indicate that an unaUractive physical appearance may evoke an unfavourable social response in many facets ofsocial interaction btit the place ol dentofacial anomalies in this context has not been satisfactorily assessed. The individual's adjustment to his own imperfections in dental alignment is variable and there is no evidence that children with visible irregularities will in general be emotionally handicapped. Effectiveness studies have yet to be undertaken but the factors which will have to be taken into aecount in assessing ihe benefits ol orthodontic treatment are the definition of treatment need, treatment standards, the disadvantages of treatment and the influence of other determinants of dental health. The need for further research is underlined.

Key words: dental health; malocclusion; orthodontic treatment; social implications.

W. C. Shaw, Department of Orthodontics, Welsh National School of Medieine, Heath Park. Cardiif, United Kingdom.

Aecepted for publication 11 November 1979.

PART I Unfortunately, studies examining the relation- THE EFFECT OF MALOCCLUSION ON ship between malocclusion and periodontal disease have produced conflicting results with some reports DENTAL HEALTH supporting a causal link (8, 54, 87, 97, 107), while PERIODONTAL HEALTH others do not (10, 39, 41, 49, 65, 86, 110). The The standard text books, both for orthodontics and considerable variations in the study groups used periodontology, regard malocclusion and mal- and the criteria for measurement employed, make alignment of teeth as predisposing or aggravating compai-ison between studies very difficult. How- factors in chronic gingivitis and chronic periodonti- ever, it would appear that many of the conflicting tis (44, 50, 85). It is assumed that the mechanical and contradictory findings arise from these varia- removal of bacterial plaque, the major aetiological tions in study design. Thus the inclusion of dental factor in the development of chronic gingivitis (80), students, with potentially high standards of oral from malaligned teeth demands greater patient hygiene, failed to show an association between dexterity, which may not be achieved under nor- malalignment of teeth and gingival and periodon- mal circumstances. Furthermore, excessive occlu- tal disease (8, 39, 55, 60, 107). Similarly, in the sal forces placed on maloccluded teeth may result study of BEAGRIE & J.-MVIES (10), where all patients in accelerated periodontal breakdown (123). for inclusion in the study had to exhibit perfect oral

0.^0I-5661/80/010036-10$02.50/0© 1980 Munksgaard, Copenhagen Denial and social effects of malocclusion 37 hygiene, there was no correlation between poste- other hand was not consistently associated 'with rior tooth irregularities and periodontal disease periodontal deterioration, though the tendency scores. increased in more severely crowded cases. This It has been suggested (4) that at the extremes of approach should be considered in future studies. oral hygiene, the effects of tooth malalignment on Clinical studies indicate that gingival exposure gingival and periodontal disease will be masked. In produced by incompetent lips is associated with an this respect it is worthy of note that, in studies increased inflammatory response (35, 62). Such a employing both patient and student groups, signifi- modifying effect appears, however, not to result cant relationships between malaligned teeth and from increased plaque accumulation (7, 62) but gingival inflammation were observed in the patient dehydration of the gingiva (62). but not the student groups (8, 107). AiNAMO (4), The role of occlusal forces in the initiation and who found a significant relationship between mal- progress of periodontal disease has been debated for occlusion and gingival inflammation in a gt-oup of many years; it has, however, been observed in army recruits, suggested that in the presence of research with animals that excessive reciprocal and average oral hygiene, malalignment of teeth will be lateral (jiggling) forces on a healthy periodontium, an aggravating factor in periodontal breakdown. or one exhibiting chronic gingivitis, results in Nevertheless, even in this study the effects of widening of the periodontal membrane but not malalignment were only noted in the incisor and pocket formation (36, 125). In a recent report premolar segments, being non-existent in the molar which considered epidemiology, aetiology and areas. The studies of SANDALI (107) tend to confirm prevalence of periodontal disease, it was stated that the potential detrimental effects which incisor "Excessive occlusal forces in man may aggravate crowding may have upon gingival and periodontal periodontal bone loss, especially in individuals with tissues. parafunctional occlusal habits such as bruxism. It A further problem with many studies has been appears, however, that occlusal forces are unable to the relatively crude measurement of malocclusion initiate gingivitis or periodontitis" (131). In rela- and the failure to take into account irregularities tion to this it is interesting to note that the most likely to be associated with periodontal supporting structures of teeth in crossbite do not deterioration. Moreover, both gingival and mal- suffer more destruction (42). occlusion scores have tended to be recorded as averages of whole mouth results. For this reason CARIES SANDALI (107) used a contact point score and Few studies have considered the relationship be- investigated only the mandibular incisor segment. tween malocclusion and caries and again the The results indieated that when these scores were reports are inconclusive. Thus, a higher than compared with gingival inflammation and pocket normal ineidence of caries has been found with measurements, a significant relationship existed in certain malocclusions but a lower than normal all groups including dental students. In any future incidence with others (2). MiLLER & HoBSON (87), investigation it would seem pertinent to consider were unable to find an association in 12-year-old individual tooth irregularities in determining the children but found at 14 years that the DMF rate relationship of malalignment to disease. was higher in the malocelusion group. Similarly, Specific malpositions of groups of teeth have HixoN et al. (56) found that dental students with been considered important, in particular increased malocclusions had a higher DMF than those with overbite and overjet. However, again, their im- excellent occlusions but the effect was limited to portance to periodontal disease has not been smooth surfaces and did not apparently apply to established (8, 41, 53) although some evidence has those areas of irregular interproximal contact. In supported an association (34, 97). Of particular contrast, KATZ (65), found that caries prevalence interest is the study of SERGL (111), where increased was significantly lower in incisors that were crowd- susceptibility to periodontal disease was found to be ed than in those which were not. associated with a number of specific anomalies. The establishment of a causal relationship is These were Class III malocclusion, anterior cross- complicated by the fact that primary or permanent bite and traumatic deep overbite. Crowding on the tooth loss through caries may in itself lead to 38 SHAW, ADDY AND RAY malocclusion. Thus, care must be taken in drawing JARVINEN (64) found the risk to be almost three comparisons between ideal occlusion and mal- times greater where the overjet was 6 mm, or more. occlusion groups where caries susceptibility, inde- Paradoxically, peak prevalence for injury appears pendent of occlusal effects, may differ. to occur at an earlier age than that at which orthodontic treatment is normally initiated (43). MANDIBULAR DYSFDNCTION Occlusal interferences have been dellned as occlu- UNERLIPTED TEETH sal contacts hampering or hindering smooth glid- In certain eireumstances, particularly where reliev- ing harmonious jaw movements with the teeth ing extractions have not been performed, teeth maintaining contact (99). Such interferences are remain unerupted. Radiographic surveys of dental considered to predispose to bruxism, increased school patients have shown the incidence in Cauca- tonus oi masticatory muscle and spasm from which sian adults to be around 15%, third molars in pain may arise. Such temporomandibular joint particular being involved (5, 29). Prophylactic dysfunction and parafunctional activity would space provision or removal of such teeth is generally appear to be multifactorial phenomena in which considered preferable in the young, since resorp- emotional anxiety may play a significant role (119). tion of adjaeent teeth or cystic enlargement of the Some experimental studies have demonstrated folliele may ensue; if removal becomes necessary in that dysfunctional symptoms may be precipitated the elderly patient, the risk of surgical or anaesthe- by the placement of occlusal interferences (20, 100). tic complication is greater. Other studies, however, have failed to support such The prevalence of pathological sequelae is un- findings (30, 108) and YEMM (132) concluded on known, however, and although radiographic sur- the basis of work with animals that bruxism has a veys of edentulous populations demonstrate that central rather than peripheral origin. many symptomless unerupted teeth remain un- More important than temporary interferences is detected (15), they tell nothing about patients the consideration of the constant presence of dis- where removal became necessary. AITASALO el al- placing contacts. Studies of bruxism have shown an (5) found a deerease in the prevalenee of impaeted association with occlusal disturbances in adults (14) third molars with an inerease in age, due presum- and in 12-year-old children (77). Emotional and ably to symptoms which had necessitated extrac- genetic factors have emerged as the important tion. In eontrast, the frequency of impaeted canines factors in other studies (78, 93). Studies on clinic was approximately the same in diflerent age groups populations have shown a high prevalence of a from 20 to 69, suggesting perhaps that these teeth variety of occlusal disturbances when compared may give rise to few problems in adult life. with a control group (3, 18, 40, 103) and epidemio- logically, combinations of those ocelusal interferen- SEVERE FUNCTIONAL DISABILITY ces were significantly more frequent in individuals Even the most severe deformities of the jaws sueh as with, than in those without, dysfunction (88). eleft lip and palate, skeletal open bite and mandi- In several of the studies discussed, uncontrolled bular prognathism appear to be associated with tooth loss rather than primary malocclusion per se surprisingly little functional disability. Thus the have provided the oeclusal interferences and it general awareness that teeth are involved in the would seem likely that certain types of irregularity production of speech does not imply a causal would be potentially more harmful than others. relationship between malocclusion and speech pro- The situation is further complicated by the inci- blems (121). Similarly, almost no difference has dence of dysfunction syndrome in individuals with been reported between subjects with excellent ideal occlusions. Longitudinal data on the associa- occlusion and those with most types of malocclu- tion of occlusal interferences and TM joint dysfunc- sion in terms of mastieatory eflicieney (38). tion is not available. In summary, therefore, there is little direct evidence that dental irregularities will be consis- INCISAL VULNERABILITY tently assoeiated with poor dental health. Even It is well documented that prominent incisors are where associations can be demonstrated, the poten- more liable lo sustain accidental injury (64, 94). cy of the effect is uncertain since long-term influen- Dental and social effects of malocclusion 39 ces have not been traced. Such cross-sectional data only judged as less socially attractive but are in fact as have been presented do not support the view less socially skilled (47). Such findings suggest that that malocclusion predisposes to premature loss of prejudices against the unattractive determine not the dentition (31). only the approval they will receive from teachers and peers but also their e\'entual behavioin\ and are thus self-fulfilling prophecies (104). This might PART 2 be predicted a priori on the basis of the consider- THE EFFECT OF MALOCCLUSION ON able evidence for a causal relationship between social feedback and self image on the one hand and PSYCHOLOGICAL WELL-BEING behaviour on the other. There are two interrelated ways in which unaesthe- The face, and oral region in particular, appears tic ocelusal traits may operate against the psycholo- to be of pi-imary importance in determining attrac- gical well-being oi the individual, namely un- tiveness (12, 28, 74, 126) and since individuals with favourable social response and poor self esteem. deformities of the face may be placed at the lowest end of the attractive/unattractive continuum it SOCIAL RESPONSE might be predicted that they would suffer negative There is a growing volume of literature which stereotyping to a considerable extent. Although indicates that physically unattractive individuals there has been little experimental evaluation of the make less favourable first impressions than attrac- effect of facial deformity in a real life setting (23). tive ones. In the main, evidence for the salience of verbatim accounts of facially deformed individuals appearance cues has been derived from studies testify to the difficulties encountered by them in involving little or no interaction, but even where social interactions (83). The specific relationship this has taken place, differences in physical attrac- between dental appearance and interpersonal tiveness continue to be systematically related to judgement is poorly defined at present. Attempts to social acceptance (1). Researeh has highlighted the evaluate the response of others to dentofacial traits mutual uneertainty and unease which character- have been made by SECORD & BACKMAN (109) and ises interaction between a normal person and one SERGL & STODT (1.12). SECORD & BACKMAN (109) who is stigmatised (26, 37, 69), and GOFFMAN (46) identified certain dentofacial charactei-istics v\ hich has provided a psychosocial framework lor under- may be important in impression information, standing how prejudice may operate against the though they also found that the salience of such deformed. characteristics was low with regard to the fi\'e Research with children indicates that physical stimulus individuals in their study. Their investiga- appearance is important in biasing judgements of tion, however, could onh' be regarded as explora- social acceptability, ability and personality, wheth- tory in view of the limited nature of the experiment. er the judges are adults or other children. It is In a carefully structured investigation, SI:RC;L & consistently found that teachers have less favour- STODT (112) found that minor variations in tooth able academic expectations in the ca.se of unattrac- position could be a significant determinant for the tive children (9, 25), and rale their general behavi- overall aesthetic impression of a face. The teeth also our and personality less favourably (102). Children seem to be an important target for teasing and themselves see peers who are ]Dhysically attractive ridicule amongst .school children, 7% of whom are as more socially attractive (19, 32, 70), and un- teased about their teeth once per week or more attractive children are more likely to be the victims (117). of bullying (81). In many of the above studies bias occurred in the absence of any real differences in SELF ESTEliM performance or conduct, and in one study children There is a considerable weight of opinion that an who differed in physical attractiveness were foimd mdividual's level of satisfaction with facial appear- to have equivalent IQ's (25). Yet there is evidence ance ina\' have important implications for his self that unattraetive ehildren aehieve less edueational- esteem (17, 63, 82, 118, 120, 124, 129). However, ly (106) and a recent study with eollege students there has been little in the way of systematic study showed that the physically unattractive ai'e not of the area to shed light on the actual effects of 40 SHAW, ADDY AND RAY malocclusion on the individual's perception of self ment on sociopsychological parameters has been and in a recent American study there were no published (105). This 5-year follow-up of individu- demonstrable differences in body-image and self- als failed to demonstrate benefits from treatment in concept satisfaction between a prospeetive ortho- terms of social and personal experience when dontie patient sample, a treated group and a compared with an untreated control group with general population sample (71). similar defects. This study must, however, be A number of investigators have examined the criticised since there was no pretreatment assess- impact of cleft lip and palate on the social integra- ment to allow comparison of the attitudes and tion oi individuals who possess such trails (24, 95, feelings of the groups initially. Although there are 122) and on the individual's adjustment to them no further studies available for comment, we might (21, 22, 27, 73, 128). In general it would appear consider factors which could complicate effective- that as a group, ehildren with cleft lip and palate ness studies. are not typieally maladjusted or seriously disturbed emotionally, although they may have some pro- ACCURACY OF DEFINITION OF TREATMENT NEED blems of social acceptanee. As adults they marry Though there are grounds for suspecting that and become steady wage earners but may be more certain dental traits may possibly harm long-term restricted in their social life. It seems unlikely, dental health and psychological well-being, precise therefore, that individuals with less extreme cosme- definition of need is difficult. Firstly, malocclusion tic oral defects will have serious emotional difficul- is not a disease but a variation from "ideal". Even ties but the question remains to be more fully "ideal" arrangements may in an evolutionary sense investigated. be anachronistic since the rapid evolution of diet- In summary, there is no specific, direct evidence ary habits with the discovery of fire and introduc- that unfavourable stereotyping operates against tion of erop gathering has out-stripped dental individuals with visible dental irregularities or that evolution. Archaeological studies indicate that in it interferes with personality development. It seems the primitive state, the dentition was subject to a reasonable to suspect, however, that stereotyping varying degree of attrition which rapidly altered may operate with unfavourable effect on at least the shape and interproximal relationships of the some individuals, particularly those exhibiting teeth (11, 113). There is also evidence to suggest gross variation from the norm. It is also likely there that the dentition unaltered by attrition is more will be considerable variability of adjustment to prone to caries and periodontal disease (91), and different maloeelusions, since the relationship be- this mciy account in part for difficulties in determin- tween actual dental arrangement and self esteem ing the relationships between dental health and will depend on a critical balance between the various present day dental arrangements including individual's perception of own dental appearance, ideal occlusions. Tight, even interproximal, con- social feedbaek and his constitutional strength and tacts are eonsidered desirable for periodontal environmental supports. health but these are apparently not present for the majority of teeth within "normal" or orthodonti- eally eorrected occlusions (92), and it seems that uneven marginal ridges are oi far less importance PART 3 than the presence and extent of plaque (67). Seeondly, since only a minority of malocclusions THE EFFECTIVENESS OF TREATMENT can be regarded as seriously handieapping (90), The effect on gingival health of realigning teeth, decisions to provide and aeeept orthodontic treat- measured over a period of time, has not been ment must be arrived at by a process of negotiation investigated. The need for such extended studies (6). Despite a lack of satisfactory data, it remains has been recommended (49), particularly since a the responsibility of the profession to give advice on large amount of orthodontie treatment is carried dental health matters on the basis of current beliefs out for reasons of periodontal health, and such and teaehing. With regard to judgements of ap- beneficial effeets have been inadequately estab- pearance, however, greater exchange of opinion is lished (68, 101). One study of the effect of treat- possible. It seems likely that dentists, and in Denial and social effects of malocclusion 41 particular orthodontists, operate on a rather more this was placed among a group of decoy photo- critical dental-aesthetic scale than society in gene- graphs (114). ral (48, 59, 89, 98, 116), though there may be considerable variation between dentists in the TREATMENT STANDARDS extent to which these standards will be imposed in There are a number of reasons why the end result of recommendations of treatment for the individual orthodontic treatment may fall short of anatomi- child. What does seem likely is that there will be cally ideal tooth alignment. These include the relatively few occasions where the dentist or ortho- operator's level of expertise, financial constraints dontist will dispute the justification for treatment and poor patient cooperation. Even treatments where this has already been proposed by an incorporating high levels of technical excellence individual child or parent. are subject to recognised limitations (61). The Thus, the aesthetic implications of malocclusion results of a retrospective study of treatment changes though largely unexplored should not be under- in the U.K., indicate that orthodontic therapy in estimated, for they provide perhaps the most general reduces the severity of the irregularity important consumer motive for seeking treatment rather than eliminating it (96). (33, 51). In fact, there is some evidence to suggest that adolescents may prefer straight teeth to heal- DISADVANTAGES OF TREATMENT thy ones (45). It is of some concern, therefore, that Among the reported disadvantages of treatment self and parental judgements of dental appearance are the cost to family or State, the possibility that can be imprecise. On the other hand, there is an the child may find the experience distressing (75, apparent low awareness of certain anterior irre- 84) and that cooperation will not be sufficient to gularities. INCERVALL & HEDEGARD (59), for ex- allow satisfactory completion of treatment (52, 89). ample, recorded a 67% objective frequency of Orthodontie treatment may produce not only short maxillary incisor irregulai-ity in a sample of 278 18- tei-m advei-se change in both oral hygiene and year-old males, but self-reported frequeney was gingival health (72, 101), but permanent losses in only 24%. Accuracy of self perception may be even gingival attachment and alveolar bone height poorer for younger individuals. When 10-12-year- (133). There has been some speculation that ortho- old children were asked to choose a picture display- dontic treatment may predispose to mandibular ing teeth like their own fi'om a series of facial dysfunction problems (13). Howe\'ei', since the drawings representing different dental arrange- natural history of the condition has not been ments (57), only 13% with anterior crowding studied, incipient dysfunction may equally well be identified eorrectly, only 11.1% with spacing iden- present in pretreatment individuals (130). This and tified correctly and only 7.5% with maxillary the other points mentioned remain to be fullv protrusion identified correctly. explored. Perceptual errors have also been demonstrated in the opposite direction. For example, in groups of OTHER DETERMINANTS OF DENTAL HEALTH adolescents with objectively good occlusions, be- Finally, effeetiveness of treatment has to be judo-ed tween one third (58) and one half (76) reported over a long period of time since benefits regarding dissatisfaction with their own teeth. Such subjec- dental health in pai'ticular may only be realised by tive/objective discrepancy must presumably ac- adtilthood. Yet many other factors iniluence longe- eount in part for the poor correlation between vity of the dentition. Of particular relevance is the objective orthodontie indices and oral self image level of importance which the individual attaches (66). Parental awareness of maloccltision may also to the retention of his dentition. Among the faetors be imprecise and in the Child Dental Health Sur- which may influence this ai'e sex, .social class, vey (127), almost half of the parents of children parental attitude, cultural, regional and national with upper anterior crowding seemed ttnawat-e of factors. Other influences are individual variations the condition. In a recent South Wales study, it was in susceptibility to dental disease, availability and found that one third of a group of 200 12-year-olds uptake of dental services, and the impact of and one third of parents were unable to identify a personal and public preventi\'e measures, such as dental photograph of the child's own teeth when diet control, tooth brushing and water fluoridation. 42 SHAW, ADDY AND RAY

In this i-espect, it may be something of a paradox invoke caution before accepting their long-term that orthodontic treatment is generally reserved for presenee. children with higher levels of general dental care The emotional handicap imposed by an un- and oral hygiene. It is possible that dissatisfaction aesthetie dental appearance may have a significant with dental aestheties inOuenees a premature re- impact on individual well-being, partieularly for quest for tooth extraction and dentures and further, children who are stigmatised or ridiculed by their that individuals will be less likely to care for their peers and come to view themselves as inadequate. teeth if they regard them as unattractive, though On the other hand, minor imperfections in dental one study of toothljrushing found no improvement appearance may be ol little real significance and lor subjects who had completed orthodontic treat- the demand for cosmetic correction is unlikely to ment (79). bear a simple relationship to the degree of anatomi- Thus, even in the event that associations between cal deviation. malocclusion and dental disease could be demon- Since the effects of malocclusion have not been strated conclusively, it would be premature to satisfactorily evaluated, the benefits of orthodontic assume that the elimination of dental irregularities treatment must remain in question. The British would necessarily increase the life span of the Dental Association Memorandum on Orthodontic dentition. The magnitude of benefit confei red by Services (16) defined the aims of orthodontic orthodontic treatment would still have to be eva- treatment as being "to produce improved function luated alongside all other determinants of dental by the eorrection of irregularities and to create not longevity, especially successive improvements in only greater resistance to disease, but also to preventive techniques. improve personal appearance, whieh later will contribute to the mental as well as to the physcial well-being of the individual." Some 25 years later, DISCUSSION the merit ol these aims remains unquestionable. It is a matter of some importance for dentists to With a small number of exceptions, however, know whether irregularity of the teeth has an eifect definition of the occlusal characteristics to which on the dental health and psychological well-being these efforts should be directed remains vague and of the individual. At the present time, theory, it is uneertain to what extent the high expeetations assumption and clinical impressions fotm the basis of treatment outcome voiced by consumers (115) for corrective treatment and the allocation of can be realised. Intensive research of the subject resources., would seem overdue. While it may seem likely that dental irregulari- ties will have a causal association with periodontal disease and caries, recent investigations have pro- REFERENCES duced confiieting results. This could be due to a 1. ADAMS, G. R.: Physical attractiveness research. Toward lack of sensitivity in the assessment criteria adopted a developmental social psychology of beauty. Hwii- or merely to the fact that dental disease results from Devetop. 1977: 20: 217-239. the interaction of more important factors which 2. ADIJ:R, P.: The incidence of dental caj'ics in adolescents generally outweigh occlusal features. Similarly, the with different occlusions. J. Dent. Res. 1956: 35: 344-349. multifaetorial aetiology of mandibular dysfunction 3. AGERHI;RG, G., GARLSSON, G. E., ERIOSON, S., LUNDBERG, M. & OBERG, T.: Funktionsrubbningari tuggapparaten. syndrome makes the strength of its association with Enbetttysiologisk, rontgenologisk och serologisk undei- dental irregularity uncertain. In contrast, sofi sokning. Sven. Tandtaeti. Tidstcr. 1970: 62: 1192-1211. tissue injury from traumatic deep overbite demon- 4. AiNAMo, J.: Relationship between malalignment of the strates an unquestionable causal relationship, and teeth and periodontal disease. Scand. J. Dent. Res. 1972: there is evidence that lip incompetence in associa- 80: 104-110. 5. AITAS,^LO, K., LEHTINEN, R. & OKSALA, E.: An ortho- tion with incisal prominence hastens periodontal pantomographic sttidy of prevalence of impacted teeth. destruction and increases the vulnerability of the Int. J. Orat Surg. 1972: /; 117-120. anterior teeth to aecidental injury. In addition, 6. ALBRECHT, G. L.: The negotiated diagnosis and treatment potential hazards associated with unerupted teeth, of occlusal problems. Soc. Sci. Med. 1977: //.• 277-281. although ill-defined, are sufficiently serious to 7. ALEXANDER, A. G.: Habitual niouthljreathing and its elfcct on gingival health. Paradontotogie 1970: 24: 49-55. Denial and social effects of malocelusion 43

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