# Positional and dimensional osseous characteristics of the temporomandibular joint in female patients with skeletal class III malocclusion and disc displacement, with and without reduction

## TL;DR

This study compares the bone structure of the jaw joint in women with a specific bite issue and disc displacement, finding significant differences in position and size.

## Contribution

The study identifies unique osseous features in TMJ for skeletal Class III malocclusion patients with disc displacement.

## Key findings

- DDR/DDWR group had a more superior and anterior mandibular fossa location.
- DDR/DDWR group showed steeper anterior wall inclination and smaller mandibular fossa width.
- DDR/DDWR group had larger anterior and medial joint spaces and more posterior condylar positions.

## Abstract

This study aimed to compare the dimensional and positional osseous features of the temporomandibular joint (TMJ) in patients with skeletal Class III malocclusion, female patients without temporomandibular disorders (TMDs), and those with TMDs presenting as disc displacement with/without reduction (DDR/DDWR).

Adult patients with skeletal Class III malocclusion and average vertical facial pattern (Mandibular plane inclination = 37 ± 5°) were categorized into the TMD group comprising patients with DDR/DDWR and the non-TMD group. Three-dimensional standardized TMJ analysis was performed using cone-beam computed tomography, which included assessments of the mandibular fossa (MF), mandibular condyle, TMJ spaces, and vertical and anteroposterior intra-joint condylar positions.

The MF location in the DDR/DDWR group was significantly more superior (p < 0.0001) and anterior (p = 0.012) relative to the respective planes. The MF width was significantly lesser (p = 0.001) with a steeper (p < 0.0001) anterior wall inclination in the DDR/DDWR group than in the non-TMD. The mandibular condyles were located significantly more laterally (p = 0.016), at a greater distance from the midsagittal plane, in the DDR/DDWR group than in the non-TMD. The anterior and medial joint spaces were significantly larger (p < 0.0001) and the intra-joint condylar positions were more posterior and superior (p < 0.0001) in the DDR/DDWR group than in the non-TMD.

The positional and dimensional osseous characteristics of the TMJ differed significantly between patients with skeletal Class III malocclusion without TMDs and those with DDR or DDWR.