Effects of occlusion modification on the remodelling of degenerative mandibular condylar processes

Abstract

Objective The temporomandibular joint (TMJ) displays a high remodelling capability in response to occlusion changes. The purpose of the current study was to investigate the responses of TMJ condyles of growing mice to the installation of a unilateral anterior crossbite (UAC) prosthesis and the replacement of the UAC prothesis with a bilateral anterior elevation (BAE) prosthesis. Materials and Methods C57BL/6J mice were randomly assigned to the blank control and experimental groups. In mice in the experimental groups, UAC was created, while in others, BAE was created after the creation of UAC or removal of UAC. Changes in TMJ condylar cartilage and subchondral bone were assessed. Results The degradation of condylar cartilage induced by UAC was reversed by BAE, as evaluated by cartilage histochemical changes, collagen II‐positive area, collagen X‐positive chondrocytes and expression levels of Adamts‐5, Mmp13, Tnf‐α and Il‐1β. Subchondral bone was assessed based on the subchondral bone volume, the number of TRAP‐positive cells and the Opg/Rankl ratio. Conclusion The growing mouse TMJ condyle displays a high remodelling capability, which can be degenerative or rehabilitative in response to the creation of UAC and the replacement of UAC with BAE. Early correction of occlusion is beneficial for the recovery of degenerative condyles.

Cone-Beam Computed Tomographic Assessment of the Mandibular Condylar Volume in Different Skeletal Patterns: A Retrospective Study in Adult Patients

“…Considering the literature previously reported, it is known that the masticatory muscle activity load is mainly transmitted to the teeth, the surrounding bone and the TMJ [31]. The chewing forces of patients with divergence and increased total goniac angles are closer to the TMJ than in patients with relatively small angles; therefore, the force acting on the condyle of hyperdivergent patients is higher than the force acting on the condyle of hypodivergent patients [35,36]. This leads to the assumption, as reported by this study, that the mandibular condyle might be smaller in patients with increased vertical patterns [3,16].…”

Elder Mice Exhibit More Severe Degeneration and Milder Regeneration in Temporomandibular Joints Subjected to Bilateral Anterior Crossbite

“…BAE induced a proliferative response in the mandibular condylar cartilage, characterized by increases in the cell number, matrix amount, and cartilage thickness ( Liu et al, 2019 ). This proliferative behavior makes BAE a useful tool to promote rehabilitation in the degraded cartilage ( Zhou et al, 2020 ). In cartilage under osteoarthritic changes, chondro-progenitors are stimulated to proliferate or differentiate ( Jiang et al, 2016 ).…”

“…BAC was removed at the seventh week in a subset of mice, which accepted BAC treatment at the age of 6 weeks or 28 weeks, and maintained for another 4 weeks after BAC removal. The cessation of BAC was conducted using the methods as we previously reported ( Zhang et al, 2015 ; Zhou et al, 2020 ).…”

“…The percentage of the Col-X positive cells number to the whole cells number of the farmed cartilage was calculated. For details, please refer to the previous publications ( Liu et al, 2014 ; Zhou et al, 2020 ; Zhang et al, 2021 ).…”

TMJ arthroscopy with hyaluronic acid: A 12‐month randomized clinical trial

“…Temporomandibular disorders (TMDs) affect the temporomandibular joint (TMJ), masticatory muscles, and associated structures (Zhou et al., 2020). These disorders affect around 5%–12% of the general population, with an annual incidence of 3.9% (Slade et al., 2016).…”