Region-specific bone mass changes in rat mandibular condyle following ovariectomy

Area of Science:

• Oral and Maxillofacial Surgery
• Endocrinology
• Bone Biology

Background:

• Estrogen deficiency is known to affect mandibular bone.
• Limited research exists on estrogen deficiency's specific impact on the mandibular condyle.
• Understanding region-specific changes in the mandibular condyle is crucial.

Purpose of the Study:

• To investigate region-specific histomorphometric changes in the anterior and posterior mandibular condyles following estrogen deficiency.
• To compare bone dynamics in sham-operated and ovariectomized female rats.

Main Methods:

• Histomorphometric analysis of anterior and posterior mandibular condyle regions.
• Comparison between sham-operated (Sham) and ovariectomized (Ovx) female Fischer rats.
• Evaluation of bone volume, bone turnover, osteoclast number, and eroded surface.

Main Results:

• Estrogen deficiency (Ovx) led to a significant decline in posterior condyle bone volume (42.7%) by 60 days post-ovariectomy.
• Both anterior and posterior regions in Ovx rats exhibited high bone turnover and reduced bone volume compared to Sham.
• The posterior region showed increased osteoclast activity and reduced bone formation in Ovx rats, leading to net bone loss.

Conclusions:

• Estrogen deficiency causes significant bone loss in the posterior region of the mandibular condyle.
• Region-specific differences in bone dynamics are exacerbated by estrogen deficiency.
• These findings underscore the vulnerability of the posterior mandibular condyle to estrogen loss.