Abstract
Background: This study compares alveolar bone turnover adjacent to distally drifting maxillary first molar teeth of rapidly and slowly growing rats. Methods: Two groups of forty male rats (1 and 3 months) were sacrificed. Sera were analyzed for acid (AcP), alkaline (AlkP), and tartrateβresistant acid phosphatase (TRAP). Bone histomorphometry was done on parasagittal sections of maxillary molars. Molar drift was quantified cephalometrically. Results: Distal surfaces contained more osteoclasts and higher osteoclast percents than mesials at both ages (P<0.001). There were also more osteoclasts on the distals of the older rats as compared to the young (P<0.001). Osteoblast percents were higher (P<0.001) in the older rats on both surfaces. Mesials had higher doublelabeled surface, MAR and BFR than distals in the younger rats (P<0.001). The younger rats had higher (P<0.001) AlkP, AcP, and TRAP. There were no ageβspecific differences in rat of molar drift. A model of rate of molar drift (P<0.0015) containing bone formation measures accounts for 54.9% of the variability. Conclusions: We conclude that the bone turnover dynamics adjacent to maxillary first molars represent predominantly remodeling on the distal in both groups and modeling on the mesial only in the young rats, that distal molar tooth drift reflects alveolar bone turnover, and that alveolar bone manifests the marked reduction in bone cell activity that occurs in the rat skeleton after 8 weeks but that this reduction is compensated by recruiment or maintenance of more bone cells at these sites. Β© 1995 WileyβLiss, Inc.