Trabecular Bone Changes in Ovariectomized Rabbit Mandibles

Numerous clinical studies have suggested that the greater risk for oral bone loss in females may be correlated with osteoporosis after menopause. Knowledge of trabecular changes in edentulous bedding bone in animals with loss of ovarian function may be beneficial in the planning and treating of dental implants in postmenopausal women. The purpose of this study was to evaluate trabeculae changes in edentulous bedding bone for dental implantation in ovariectomized rabbits. Twelve adult female Japanese white rabbits were examined. The mandibular incisors were initially extracted to simulate the edentulous bedding bone for dental implants. Six animals were bilaterally ovariectomized and the other 6 were sham-ovariectomized 12 weeks after tooth extraction. The edentulous parts of distal mandibular bodies were processed undecalcified 12 weeks after ovariectomy or sham-ovariectomy and examined by quantitative trabecular bone histomorphometry. In ovariectomized rabbits, there were significant increases in trabecular separation, osteoid volume, osteoid thickness, osteoid width, eroded surface, and mineral appositional rate, and a significant decrease in trabeculae number. The results of sparser trabecular structure, more trabecular osteoid, and increased trabecular bone turnover demonstrate bone loss of mandibular edentulous trabeculae in ovariectomized rabbits and suggest that the same loss may occur in postmenopausal women.