Background: Past studies investigating the association between occlusion and TMDs have produced controversial results. The contribution of occlusal curvatures and maxillary arch dimensions to TMD symptomatology has yet not been comprehensively addressed and remains unclear. Therefore, the aim of this study was to investigate whether occlusal curvatures and maxillary arch dimensions are associated with signs and symptoms of TMDs.
Materials and methods: One hundred subjects, who consented to participate in this investigation, were examined by the first author for signs and symptoms of TMDs using the guidelines of the Research Diagnostic Criteria for Temporomandibular Disorders and according to a custom neck examination. The occlusal measurements that were performed on the study models of all subjects included the curves of Spee and Wilson as well as the maxillary intercanine, interpremolar and intermolar distances. Statistical elaboration of the data included ANOVA, student’s t-test and linear regression and was performed by means of SPSS (version 16).
Results: Subjects with smaller interpremolar distances appeared to have less pain on palpation of some masticatory and neck muscles (0.01< p <0.035). A flatter curve of Spee was associated with a higher incidence of temporomandibular joint sounds on lateral excursions (p_right=0.018, p_left=0.032). When the correlation between occlusal variables was tested, it was revealed that subjects with a steeper curve of Wilson presented smaller intercanine, interpremolar and intermolar distances (0.000< p <0.039).
Conclusion: The depth of the curve of Spee and the interpremolar distance are associated to specific signs and symptoms of TMDs.