An Observational Study of Age-Related Changes in Bite Force During Stabilization Splint Therapy in Patients with Unilateral Temporomandibular Joint Osteoarthritis

Age-related differences in temporomandibular joint osteoarthritis (TMJ OA) have been suggested; however, age-specific patterns of functional recovery following occlusal splint therapy remain insufficiently characterized. This retrospective observational study evaluated longitudinal changes in bite force across different age groups in patients with unilateral TMJ OA undergoing stabilization splint therapy. Thirty-two patients diagnosed according to the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) were categorized into three age groups (20–39, 40–59, and ≥60 years). Maximum bite force was measured repeatedly from baseline to 2 weeks and up to 6 months during the observation period following splint application. Patients aged 60 years and older exhibited significantly lower baseline maximum bite force compared with younger groups (p = 0.011), but demonstrated a gradual and statistically significant increase over the observation period (p = 0.011). In contrast, patients aged 20–39 years showed a significant improvement in bite force asymmetry after 2 weeks of treatment (p = 0.047), which was maintained throughout follow-up. These findings suggest that functional recovery patterns in unilateral TMJ OA may vary according to age, with younger patients showing earlier improvement and older patients demonstrating slower but progressive functional gains. Bite force assessment may serve as a complementary functional parameter for characterizing age-related differences in functional change in patients with unilateral TMJ OA.