Effects of Occlusal Splint Therapy on Dentofacial Skeletal Pattern in Juvenile Patients with Temporomandibular Joint Osteoarthritis

Abstract

Temporomandibular joint osteoarthritis (TMJ OA) has been generally known to be a degenerative condition of TMJ led by a pathological tissue response of the joint under a mechanical overload. The aim of this study was to evaluate the effects of occlusal splint therapy on the dentofacial skeletal pattern and symptoms of juvenile patients with TMJ OA based on the cephalometric radiograph analysis and Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD). A total of 34 juvenile patients under 16 years old diagnosed with TMJ OA based on computed tomography who visited Seoul National University Dental Hospital were studied. The patients were classified into 28 splint therapy group treated by stabilization splint for at least 6 months and 6 non-splint therapy group(control group) treated by physical therapy, medication, and behavioral control only. Pre-treatment and post-treatment clinical symptoms including subjective pain intensity, maximum mouth opening (MMO), comfortable mouth opening (CMO), number of muscle tenderness, and cortical bone erosion of mandibular condyle based on computed tomography. Cephalometric analysis of 9 angular measurements including articular angle, gonial angle, Y-axis to SN, SN to mandibular plane angle, SNA, SNB, ANB, gonial upper angle, and gonial lower angle were analyzed on each patient. Mean durations of the evaluation were 19.9 ± 9.7 months for the splint therapy group and 20.2 ± 11.4 months for the control group. Obtained results were as follows:

1. Splint therapy group showed more significant increases in MMO and CMO after treatment than control group. 2. Condylar erosion severity did not show significant decrease in both groups. 3. Pain intensities were significantly decreased after treatment in both groups, but there were no significant differences between both groups. 4. Number of positive masticatory muscle palpation was significantly decreased after treatment in both groups, but there were no significant differences between both groups. 5. Articular angle, Y-axis to SN, SN to mandibular plane angle, gonial upper, and lower angles were significantly changed in splint therapy group and Y-axis to SN, SN to mandibular plane angle, SNB, ANB, and gonial lower angle were significantly changed in control group. SNB was less significantly decreased after treatment in splint therapy group than control group.

In conclusion, there were no significant differences in condylar erosion severity and most of cephalometric parameters of juvenile TMJ OA patients between splint therapy and control groups within 20 months. Clockwise rotations of mandibles were shown in both groups, however modestly less decrease of SNB was shown in splint therapy group than control group. Further longitudinal study based on a larger population should be considered for establishing the effective treatment planning of juveniles TMJ OA patients.