The Effects of Changes in Serum Estrogen Combined with Occlusal Interference on the Morphology of Condylar Tissue and Estrogen Receptor Expression in Rats

Abstract

Objective: This study aimed to explore the contributions of estrogen fluctuations and mechanical occlusal factors to the pathogenesis of idiopathic condylar resorption (ICR) in a rat model.

Methods: An ovarian insufficiency model was established in female Sprague-Dawley (SD) rats using cisplatin, followed by the administration of a short-term oral contraceptive to manipulate estrogen levels. Occlusal interference was introduced via dental pins. Serum estradiol (E2) concentrations were measured at baseline, day 15, and week 12. Histopathological changes were assessed through H&E staining, and the expression of estrogen receptors ERα and ERβ was evaluated immunohistochemically.

Results: The serum E2 levels significantly decreased in the experimental groups compared to controls (P < 0.05), correlating with notable histopathological changes in condylar cartilage, including reduced thickness and disordered cellular arrangement. Furthermore, expression levels of ERα and ERβ were significantly reduced in the experimental groups, indicating altered responsiveness to estrogen signaling with the combined effects of hormonal manipulation and mechanical interference.

Conclusion: Estrogen and mechanical occlusal factors play critical roles in the pathogenesis of ICR. The findings underscore the need for integrated approaches to managing TMJ disorders that consider both hormonal and mechanical influences. Future research should address the long-term implications of these interactions on condylar health.