Influence of malocclusion on sleep bruxism and orofacial pain: data from a study in school children

Objectives This cross-sectional school-based study explored the influence of malocclusion on temporomandibular disorders (TMD) pain complaints, and whether this association would be mediated by sleep bruxism in a representative sample of 7- to 8-year-old children. Methods Path analysis estimated direct, indirect, and total effects of occlusal features on sleep bruxism and TMD pain in 7- to 8-year-old children. Occlusal features were assessed with Dental Aesthetic Index (DAI), orofacial pain complaints using the TMD pain screener, possible sleep bruxism based on self-reports, and probable sleep bruxism based on self-reports combined with clinical findings. Structural equation modeling analyzed data with confounding factors. Results From 580 participants, possible sleep bruxism was observed in 136 children (31.5%), probable sleep bruxism in 30 children (6.7%), and TMD pain complaints in 78 children (13.8%). Malocclusion had no direct effect on either possible sleep bruxism [standardized coefficient (SC) 0.000; p = 0.992], or TMD pain complaints (SC - 0.01; p = 0.740). When probable sleep bruxism was set as the mediator of interest, malocclusion did not directly affect probable sleep bruxism (SC 0.01; p = 0.766), nor TMD pain complaints (SC - 0.02; p = 0.515). A direct effect of probable sleep bruxism on TMD pain complaints was observed with an SC of 0.60 (p < 0.001). However, in neither case, malocclusion indirectly affected TMD pain complaints via bruxism. Conclusion Malocclusion in 7- to 8-year-old children did not directly influence possible or probable sleep bruxism or TMD pain complaints. Instead, probable sleep bruxism was strongly associated with TMD pain complaints. Clinical significance The impact of occlusal features on TMD pain complaints and bruxism has been a long-standing controversy in dentistry. However, the scientific literature linking this association may be inconsistent, mainly due to biased sample selection methods with inadequate consideration of confounders. Further research should try to identify additional risk factors for TMD pain in addition to probable sleep bruxism in children.