Stability of the LeFort I one-piece maxillary osteotomy.

The purpose of this study was to determine retrospectively the stability of the LeFort I osteotomy after one-piece maxillary impaction and wire fixation. Cephalograms of 31 patients were evaluated before surgery, immediately after surgery, in fixation, and postfixation. All subjects had characteristics of excessive vertical maxillary growth. Descriptive statistics for the absolute and relative changes of the various linear and angular parameters were calculated for the different stages. The analysis of variance general linear models procedure was used to compare the repeated measures of the total sample. From the present findings, it was concluded that (1) after the initial surgical superior repositioning, the maxilla continued to move superiorly and most of the upward movement occurred during fixation, (2) the anterior part of the maxilla moved superiorly more than twice that of the posterior part of the maxilla, (3) maxillary superior dental movement exceeded maxillary superior skeletal movement, and (4) maxillary horizontal skeletal movement exceeded maxillary horizontal dental movement. The clinical significance of the findings are discussed.