Dentoalveolar changes following maxillary distraction osteogenesis

The purpose of this study was to compare the dentoalveolar changes produced when using two different intraoperative surgical procedures for maxillary distraction osteogenesis. Eight patients were assigned into two groups according to the surgical procedure: down-fracture (DF, n = 6) vs non-down-fracture (NDF, n = 2). Lateral cephalograms and 3-D models before and after maxillary distraction were analyzed. The Mann-Whitney U test was used to compare the differences in the amounts of advancement and dento-alveolar changes between the DF and NDF groups. The significance level was established at 0.05. Although a significantly greater amount of maxillary movement was observed in the DF group (10.0 mm ± 2.2) than in the NDF group (5.9 mm ± 2.3), significantly greater arch length (8.7 mm ± 5.2) and arch width changes (6.0 mm ± 1.0) were observed in the NDF group than in the DF group, (arch lengths 3.0 mm ± 1.1 and arch width changes 3.2 mm ± 2.0). A significantly greater amount of dental anchorage loss was observed in the NDF group. The use of the NDF procedure resulted in greater amounts of dental anchorage loss than resulted from the DF procedures when tooth-borne devices were used during maxillary distraction osteogenesis. The type of surgical procedure might play an important role in the amount and direction of the dental changes.