Effect of Anterior Disc Displacement and Estrogen Deficiency on Rabbit Mandibular Condyle

Objective: In this study, we aimed to establish an experimental model of idiopathic condylar resorption by combining surgically induced anterior disc displacement and estrogen deficiency in growing rabbits. This study aimed to investigate the individual and combined effects of these factors on condylar resorption.

Materials and methods: Seventeen female Japanese White rabbits were divided into four groups: control, ovariectomy, anterior disc displacement surgery, and combination of ovariectomy and anterior disc displacement surgery. Micro-computed tomography and histological evaluations were performed to analyze changes in the trabecular bone structure and cartilage thickness of the condyle.

Results: The combined group exhibited the most significant changes in trabecular bone parameters, including the lowest bone volume per tissue volume and trabecular number and the highest trabecular separation and spacing. Histologically, the fibrous layer thinned and the hypertrophic layer thickened in the anterior and central parts of the condyle in the anterior disc displacement and combined groups. The Modified Mankin Score indicated the highest level of degenerative change in the combined group.

Conclusion: The combination of surgically induced anterior disc displacement and estrogen deficiency in growing rabbits effectively modeled idiopathic condylar resorption, demonstrating the synergistic impact of disc displacement and estrogen deficiency on condylar resorption. This model provides valuable insight into the pathogenesis of idiopathic condylar resorption.