The Effects of Micro-Osteoperforations on Tooth Movement and Bone in the Beagle Maxilla

Abstract

Introduction: The purpose of this study was to determine how micro-osteoperforations (MOPs) affect tooth movements and bone characteristics, including bone turnover, bone density, and bone volume. Methods: A split-mouth design with 7 beagle dogs was used to evaluate bone surrounding maxillary second premolars that had been retracted for 7 weeks. The maxillary third premolars were extracted and, after 1 month of healing, 8 MOPs (1.5 mm wide and 7 mm deep created with the PROPEL device) were placed without flaps around the experimental side maxillary second premolars. The maxillary second premolars were retracted bilaterally with 200 g nickel-titanium closed coil springs. Tooth movements were measured intraorally and radiographically. Microcomputed tomography analysis was used to evaluate the material density and bone volume fraction of bone adjacent to the moving teeth. Hematoxylin and eosin sections and fluorescent sections were used to examine the bone. Results: Overall tooth movements were slightly greater on the MOP side, but neither the intraoral tooth movement measurements nor radiographic tooth movement measurements showed statistically significant (p=0.866, p=0.528) differences. There also were no statistically significant differences in bone density (p=0.237) and bone volume fraction (p=0.398). Fluorescent image and histologic evaluations also showed no apparent differences near the tooth being moved. Bone healing was evident in and near the MOP sites, which had nearly, but not completely repaired by 7 weeks. Regions of acellular bone were evident extending approximately 0.8 mm from the MOP sites. Conclusions: The extent of MOPs effects on tooth movements are limited. MOPs placed 3 mm away do not increase tooth movements and have little or no effect on bone adjacent to the tooth being moved.