Occlusal Support and Temporomandibular Disorders Among Elderly Vietnamese

Purpose: The aim of this study was to analyze the associations between missing teeth, occlusal support, and temporomandibular disorders (TMD) among elderly Vietnamese. Materials and Methods: The study consisted of 145 TMD and 112 non-TMD (control group) participants aged 65 to 74 years. TMD was evaluated using Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) Axis I. An occlusal unit (OU) was defined as the cusp of a tooth coupled with the fossa of its antagonist tooth. A premolar pair was counted as one OU and a molar pair as two OUs. Dentition was divided into four occlusal support zones (OSZs) based on occluding pairs of posterior teeth by using Eichner classification: Class A had 4 OSZs, Class B had 1 to 3 OSZs or only anterior teeth, and Class C had no OSZ. Results: The TMD group lost significantly more posterior teeth (mean ± SD 5.1 ± 4.7) than the control group (4.0 ± 3.9, P = .033). The mean ± SD OUs of the TMD and control groups were 5.1 ± 4.6 and 6.0 ± 4.3, respectively, which was nonsignificant (NS). The distribution of Class A (40.7%), Class B (40.0%), and Class C (19.3%) among the TMD group was not significantly different from the control group (50.0%, 38.4%, and 11.6%, respectively, NS). The odds of having TMD were positively associated with total unilateral loss of OUs (OR = 3.4, 95% CI = 1.2-9.4, P = .020) and total bilateral loss of OUs (OR = 2.7, 95% CI = 1.2-6.6, P = .027). Conclusion: Total loss of OSZs on one or both sides of the mouth were found to be predictors of TMD among elderly Vietnamese.