Effect On Bone Mineral Density(Bmd) Of Mandible In Estrogen-Deficiency Rat

Kim, Ki Hyun; Shin, Sang Hun; Kim, Uk Kyu; Park, Bong Soo; Chung, In Kyo

Abstract

The relationship between systemic bone loss(osteopenia)and loss of oral bone has been of considerable recent interest.In dentistry,some investigators have studied using human subjects,but no firm conclusion due to many obstacles have yet been obtained.From these obstacles in the assessment of human subjects, the significance of investigations with ovariectomized rats has been proposed recently.Also,in ovariectomized rats,quantitative data on changes in the alveolar bone of mandible and basal bone of mandible using dual-energy x-ray absorptiometry(DEXA)were far fewer. The purposes of this study were to certify systemic estrogen deficiency-induced osteopenia by biochemical markers(serum osteocalcin(OC)and urinary deoxypyridinoline(DPD))and bone mimeral density(BMD)of femur by DEXA and examine changes in BMD of the rat mandible by DEXA with 24-week-old female Sprague-Dawley rats. Forty eight rats were used in this study and twenty four rats were ovariectomized bilaterally(OVX)to induce systemic osteopenia and remainders were subjected to sham surgery(Sham). The experimental rats were killed at different time interval(1st,2nd,3rd,4th,6th,8th,12th and 16th week)for histologic examination,biochemistry analysis and BMD measurement. The results obtained from this study were as follows: On histological examination,in mandible,early degeneration of periodontal ligament,early bone resorption in alveolar bone and late bone resorption in basal bone were observed. On biochemical analysis,OC and DPD were observed statistically no significancy to predict systemic osteopenia. On DEXA measurement,in OVX group,we observed statistically significant decrease from 3rd week in distal metaphysis,statistically non-significant decrease from 2nd week in alveolar bone of mandible,and statistically significant decrease at 16th week in total mandible. From these results,it could be stated that systemic osteopenia by ovariectomy was early affected in the trabecular bone of femur and alveolar bone of the mandible whereas the total mandible was affected later.