Abstract
Using a chronological lead-labeling technique, we quantitatively evaluated bone formation in the alveolar walls of maxillary first molars in normal rats. Over a 9-day period, animals were injected with EDTA-Pb a total of 4 times at 3-day intervals, and the unit volume of newly formed bone (mm3/mm2) in the alveolar walls surrounding the roots was measured with reference to the lead-labeled lines. Under normal conditions, continuous bone formation was found on the mesial side of the alveolar walls surrounding the roots. However, the pattern of lead-labeling varied between root sockets, and the unit volume of newly formed bone in the alveolar walls during the experimental period was significantly different between the five roots. Whereas a similar lead-labeling pattern was found in the cervical, middle, and apical regions of the various specimens, the site and volume of new bone formation differed slightly from the cervix to the apex. The present study demonstrates that this chronological lead-labeling technique is useful for the quantitative study of bone formation in the alveolar wall.
