Mandibular Asymmetry Index and Dental Occlusion in Patients with Temporomandibular Disorders Treated with Occlusal Splint

Abstract

Objectives: To evaluate any changes in condylar and mandibular ramus height and dental malocclusion in adult patients with temporomandibular disorders (TMDs) diagnosed with DC/TMD criteria after treatment with an upper occlusal splint. Methods: This retrospective observational study included 48 adult patients with TMDs treated with an occlusal splint in the upper arch for about 12 months. For each patient, panoramic dental X-rays were analyzed using the Habets method to calculate the asymmetry index between the condyles and mandibular branches before and after treatment. The digital dental models were also studied at T0 and T1 to define the occlusal sagittal molar relationship and the posterior dental crossbite. The statistical analysis was performed using the Shapiro–Wilk normality tests, Student t-tests, or Wilcoxon tests using the R studio software (released version 4.3.3). Results: Condylar height showed a statistically significant difference (p = 0.022) and reduced condylar asymmetry between T0 and T1. The measurement of the condylar branch showed a statistical significance (p = 0.037), revealing an improvement of the mandibular symmetry in the vertical direction after treatment. Moreover, at T0, posterior dental crossbite was found in 37.5% of patients, specifically, bilateral in 12.5%, while unilateral crossbite in 22.9% on the right and 2.1% on the left side, and Class I malocclusion was found in the main part of the sample (72.9%). Conclusions: Patients with TMDs diagnosed according to DC/TMD and treated with an upper stabilization occlusal splint in the case of symptoms of masticatory muscle dysfunction showed a symmetrization in the mandibular ramus and condyle pre- and post-treatment (T0-T1). At the same time, no clinical differences were found in the occlusal characteristics.