Impact of estrogen therapy on temporomandibular joints of rats: Histological and hormone analytical study

OBJECTIVES: This research aims to evaluate the effects of estrogen deficiency and replacement on the TMJ structures of rats. The considerable similarities in the anatomical features of rats and humans make rats a suitable model for human scientific studies. METHODS: A clinical trial was conducted on 18 female Sprague-Dawley rats grouped into three categories. The GI group included 6 female rats labelled as the control group, the GII group consisted of 6 females that received ovariectomies, and the GIII group had 6 ovariectomised females that were injected with estrogen replacement therapy in a science laboratory at King Abdulaziz University. ANOVA and Tukey HSD post hoc tests were used to determine any significant differences between the levels of estrogen among the three groups. RESULTS: The results indicate that some TMJ structures, including the articular disc and condylar cartilaginous layer, were degraded after estrogen deficiency. However, there was a slight improvement in the cartilaginous layer thickness and proliferation of chondroid cells after estrogen replacement therapy. Estrogen level was reduced in the ovariectomized rats, and while estrogen injections increased blood hormone levels, the levels did not reach those of the control group. CONCLUSION: Estrogen deficiency degraded some TMJ structures, and there is only a slight recovery after estrogen replacement therapy.