Comparative evaluation of night guard and stabilization splint therapy on temporomandibular joint function using surface electromyography and digital occlusal analysis: a DC/TMD-based study

Occlusal splint therapy is widely used in the conservative management of temporomandibular disorders (TMDs); however, the objective functional effects of different splint designs remain incompletely understood. This study aimed to compare the effects of night guard and stabilization splint therapy on temporomandibular joint–related parameters using surface electromyography (sEMG) and digital occlusal analysis. A total of 84 participants were included and divided into three groups: stabilization splint (n = 21), night guard (n = 13), and a control group of TMD patients who did not receive splint therapy (n = 50). Diagnoses were established according to the Diagnostic Criteria for Temporomandibular Disorders (DC/TMD). Mandibular range of motion (ROM), disclusion time (Δ), and masticatory muscle activity (temporal and masseter muscles) were recorded at three time points. Statistical analyses were performed using generalized estimating equations for repeated measures and, when appropriate, non-parametric Friedman tests for within-group comparisons. Baseline demographic characteristics were comparable among groups (p > 0.05). ROM increased modestly over time across all participants (mean change + 2.1 mm; 95% CI: 0.5–3.7; p = 0.008), without significant Group×Time interaction (p = 0.070). Disclusion time showed no significant longitudinal change (mean difference − 0.03 s; 95% CI: −0.12 to 0.06; p = 0.320). Right temporalis activity demonstrated significant time (p = 0.042) and group effects (p = 0.049), with stabilization splints showing lower variability and more consistent neuromuscular adaptation patterns compared with night guards. No significant interaction effects were detected for other muscles (p > 0.05). Objective functional assessment using sEMG and digital occlusal analysis suggests that stabilization splint therapy provides more consistent neuromuscular adaptation than night guard therapy, despite limited changes in disclusion time. These findings highlight the importance of objective measurement techniques in evaluating occlusal splint therapy and support the clinical use of stabilization splints when functional consistency is a primary treatment goal in patients with TMD.