Skeletal and dental movements after anterior maxillary advancement using implant-supported distraction osteogenesis in dogs.

Objective: This study evaluated skeletal and dental relapse in the dog after anterior maxillary advancement using an implant-anchored distraction osteogenesis device.

Methods: After the placement of implants into the palate, four dogs had a skeletally anchored distraction device fabricated and an anterior maxillary osteotomy performed. The distraction device was activated 0.5 mm two times each day to advance the anterior segment 10 mm in 10 days. The dental and skeletal changes were measured and compared for 26 weeks after distraction was completed.

Results: Tooth and radiographic measurements indicated that on the 10th day of distraction the average tooth advancement was 6.83 mm +/- 1.75 mm SD, and the average skeletal advancement, based on radiographs, was 8.67 mm +/- 1.25 mm SD. After 10 weeks, the average tooth advancement was 4.0 +/- 1.73 mm, and the average skeletal advancement was 8.67 +/- 3.59 mm. After 26 weeks, the average tooth advancement was 3.65 +/- 1.69 mm, and the average skeletal advancement was 8.0 +/- 1.98 mm. Bone healing occurred in all animals. The skeletal advancement 26 weeks after distraction was 85% of the initial advancement. The teeth adjacent to the distraction site initially moved 68% of the advancement, but the distance between the teeth subsequently decreased, with a resultant 36% advancement compared with the initial advancement.

Conclusions: This study showed that skeletal fixation will result in bone movement greater than dental movement, indicating the need for skeletal anchorage to advance the maxilla.