Correlation of Occlusion Asymmetry and Temporomandibular Disorders: A Cross-Sectional Study.

BACKGROUND

The association between occlusion and temporomandibular disorders (TMD) remains obscure. The present purpose was to explore the asymmetrical occlusion feature(s) potentially linked to TMDs.

METHODS

This study enrolled 148 patients with a chief complaint of malocclusion. Of those, 84 had no signs of TMD (Group-ORD1), and 64 had signs of TMD (Group-ORD2). An additional 84 patients with a chief complaint of TMD symptoms and a history of orthodontic therapy were included (Group-TMD). All patients in the study were female. Asymmetry of six occlusion variables was measured on plaster study casts and recorded as 1 for asymmetry and 0 for symmetry. The variables contain the sagittal asymmetry: the first molar mesial-distal relationship (F1), canine mesial-distal relationship (F2); the horizontal asymmetry: anterior overjet and overbite relationship (F3), posterior overjet and overbite relationship (F4); missing teeth (F5), and the weight of the asymmetrical occluding pair (F6). And logistic regression model was used for data analyses.

RESULTS

In the analyses for Group-ORD2 versus Group-ORD1, the F6 variable and the interactions of F1*F2 and F1*F2*F6 were entered into the model (all OR > 2.68). For Group-TMD versus Group-ORD1, the variables were F1, F5, and F6 (all OR > 2.39) and F4 (OR = 0.28), and the interactions were F5*F6, F1*F2*F6, F1*F5*F6, and F1*F2*F5*F6 (all OR > 2.78) and F2*F4, F3*F5, and F2*F4*F6 (all OR < 0.13). For Group-TMD versus Group-ORD2 the variables and interactions were F5, F5*F6, and F1*F5*F6 (all OR > 4.03) and F4, F4*F6 and F2*F4*F6 (all OR < 0.21) (all P < .05).

CONCLUSIONS

Patients with sagittal asymmetry, asymmetrical missing teeth, or asymmetrical weight of contact have a higher prevalence of TMD.