Endosseous titanium implants as anchors for mesiodistal tooth movement in the beagle dog

The purpose of this study was to determine the anchorage potential of titan ium implants (Branemark; 3.75 x 7 mm) with the use of a sectional arch wire technique for orthodontic mesiodistal tooth movement, as assessed by the o sseointegration of implants and tooth movement. Two implants were surgicall y placed in healed mandibular extraction sites of the second and third prem olars on each side in 4 adult male beagle dogs. The implants were surgicall y uncovered 18 weeks later, and second-stage abutments with soldered edgewi se tubes were attached. Segmented edgewise rectangular archwires (0.017 x 0 .025 inch) with a T-loop or an L-loop were placed between the implants and the fourth premolars on both sides as the anchorage unit. One segment in ea ch dog served as a loaded side, and the archwire was calibrated to produce 200 g of lateral force on the fourth premolar, The contralateral segment se rved as an unloaded side and was not subjected to orthodontic force. Sectio nal wires were activated biweekly 24, 28, 28, and 32 weeks, respectively, d epending on the magnitude and the appearance of mesial tipping movement of the fourth premolar. After mandibular impressions were taken to measure the distance between the first molar and the fourth premolar, the animals were euthanized and dissected mandibles were prepared. The specimens were then embedded in polyester resin and cut to take backscattered electron images. On the basis of these images, the percentage of peri-implant bone volume wa s calculated and defined as an index of osseointegration. The differences b etween the initial and final fourth premolar to first molar distances varie d (7.40, 8.85, 10.50, and 3.30 mm) on the loaded side, whereas the unloaded side showed no movement. Not only was there no statistical difference in t he percent of peri-implant bone volume between the loaded and unloaded side s, but there was also no statistical difference between the compression and tension sides in both loaded and unloaded implants, which suggests that th e implants maintained rigid osseointegration. In conclusion, the present st udy demonstrated that endosseous titanium implants can function as anchors for long-term orthodontic mesiodistal movement.