Self-reported pain and maximum mouth opening following occlusal splint therapy with adjunctive home-based jaw exercises across body mass index categories: A retrospective observational study

Objective To compare self-reported pain and maximum mouth opening (MMO) among normal-weight, overweight, and obese patients with temporomandibular disorders (TMD) who had received occlusal splint therapy (OST) combined with adjunctive home-based jaw exercises (JE).Methods In this study, adults with painful TMD were categorized by body mass index (BMI) as normal-weight, overweight or obese. All participants had previously received standardized OST with adjunctive home-based JE. Demographic and clinical data were extracted and BMI was reassessed at follow-up. Pain and MMO were measured. Between-group differences at follow-up were evaluated using baseline-adjusted analysis of covariance (ANCOVA) with Bonferroni-adjusted pairwise comparisons and linear regression analyses, with statistical significance set at p < .05.Results The study included 167 participants: 56 normal-weight (mean age 38.8 ± 8.7 years), 57 overweight (mean age 45.1 ± 5.2 years) and 54 obese individuals (mean age 49.6 ± 7.9 years). Pain decreased and MMO increased across all BMI categories. Baseline-adjusted follow-up pain differed significantly among groups (F[2.163]=19.8, p < .001) with higher adjusted pain in obese participants. Follow-up MMO also differed significantly (F[2,163]=61.4, p < .001) showing a smaller increase in the obesity group than normal-weight and overweight participants.Conclusion Participants with obesity demonstrated smaller observed improvements in MMO than normal-weight and overweight participants. However, diagnostic heterogeneity and residual confounding limit attribution of these differences to BMI category.