Photodensitometric evaluation of osseous repair following Le Fort I osteotomy

This study evaluated photodensitometry as a noninvasive method for quantitating bone mineral content (BMC) and osseous repair after Le Fort I osteotomy. Le Fort I osteotomies were performed on 6 Macaca fasicularis monkeys; maxillas were either advanced (Group I, n = 3) or impacted and advanced (Group II, n = 3). Postoperative, standardized lateral cephalometric films were taken at weekly intervals up to 25 weeks and osteotomy site repair was studied using photodensitometry. Segment stability was also evaluated and correlated with measured densities. In both experimental groups, clinical stability occurred at about the same time (45.7 and 48.7 days postoperatively) despite large differences in the size of the initial surgical defects. The net rate (slope) of osteotomy site remineralization was significantly different (Group II > Group I), but the relative difference in film absorbance between the osteotomy site and adjacent bone at the time of clinical stability was the same. This difference can be extrapolated from early postoperative films and may constitute a useful parameter for predicting when clinical stability will be achieved.