Abstract
Introduction: The association between malocclusion, psychosocial characteristics and oral health-related quality of life (OHRQoL) remains complex and controversial. A large number of recent studies using standardised instruments have shown an association between malocclusion and OHRQoL, but the nature of that association has recently been questioned, with the notion that psychosocial characteristics may, in fact, play a confounding role in the relationship. Furthermore, there has been considerable interest in the association between malocclusions and temporomandibular disorders (TMDs). Reviews during the last century concluded that dental occlusion is only weakly related to TMDs and that no causal relationship could be determined. Moreover, the bulk of the literature also reinforces the notion that TMD shares common behavioural and psychological characteristics with other chronic pain conditions.
In light of the reported associations, the objective of the current study was to explore the possible confounding roles that various psychosocial characteristics (such as self-esteem, somatisation and self-perception of body image play in relation to both malocclusion and OHRQoL, and malocclusion and TMD.
Method: The study protocol was approved by the Regional Ethics Committee. The sample for this cross-sectional study comprised 353 young adolescents (48.4% female). This included 272 12-to-13-year-old participants enrolled with the Otago District Health Board school dental service, who were selected from the five largest intermediate schools in Dunedin, New Zealand, and a consecutive clinic sample of 81 similarly aged patients attending the orthodontic clinic at the University of Otago Faculty of Dentistry (Dunedin). Each participant completed a self-administered questionnaire and underwent a clinical examination. Information collected included socio-demographic characteristics (sex, ethnicity and household deprivation), psychosocial characteristics (self-esteem, general wellbeing, somatisation and self-perception scores for body image) and malocclusion (Dental Aesthetic Index). OHRQoL was measured using the 16-item impact short-form CPQ11-14 questionnaire; and self-reported TMD was assessed using three items from the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD).
Results: The CPQ11-14 score was strongly associated with psychosocial characteristics. Linear regression modelling of the CPQ11-14 score showed that socio-demographic characteristics were predictors, but the model’s overall explanatory power was low (R2 =0.05). This increased slightly with inclusion of the clinical variables. When the psychosocial variables were added, however, the R2 increased to 0.50; all psychosocial variables (except self-esteem) were strongly associated with the CPQ11-14 score. General wellbeing was the strongest predictor. Self-reported TMD was associated with higher somatisation scores and with body image concerns (p<0.001). TMJ clicking was more common in adolescents with mild or no malocclusion (31.1% with clicks) than in those with a moderate (17.6%) or handicapping malocclusion (12.1%; p=0.018). Relative to patients sent by their parents, adolescents who were self-motivated to seek treatment had greater somatisation scores and more body image concerns (p<0.001), and tended to report TMD clicking more often (26.3% and 7.7% respectively; p=0.41).
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Conclusions: Psychosocial characteristics are important contributors to OHRQoL in adolescents and appear to be more important than socio-demographic characteristics or malocclusion. With regards to TMD, self-reports of TMD in adolescents are associated with propensity to somatisation and concerns with body image. Self-reports of TMD were more common in adolescents with no or minor malocclusion than in those with severe or handicapping malocclusions. Care-seeking adolescents have increased somatisation, body image concerns, and tended to report TMD more often.