Soft and hard tissue changes after bimaxillary surgery in Turkish female Class III patients.

INTRODUCTION: Treatment of severe Class III malocclusion frequently requires a combination of orthodontics and orthognathic surgical procedures. The aims of this retrospective study were to assess the results of bimaxillary surgery on Turkish female subjects presenting with Class III malocclusions and to evaluate the correlation between soft and hard tissue changes.

MATERIAL AND METHODS: The sample consisted of 44 Turkish female Class III patients (mean age was 28.3+/-3.7 years) treated with bilateral sagittal split osteotomy and Le Fort I advancement with maxillary impaction. Lateral cephalograms were taken immediately before and 2.6+/-0.7 years after bimaxillary surgery. Paired t-test, Pearson correlation test and linear regression analysis procedures were used to assess the degree of correlation in terms of soft to hard tissue changes between the two cephalograms. All subjects presented with a presurgical concave profile.

RESULTS: Maxillary advancement and impaction combined with mandibular setback surgery corrected the facial concavity and the improvement of horizontal and vertical positions. The lengths of the upper and lower lips and the horizontal position of the soft tissue pogonion were improved. The decrease in facial convexity angle was correlated with the increases in SNA angle and N-A distance. The significant increase in labiomental fold depth was significantly correlated with the significant decreases in N-ANS and ANS-Gn distances. The protrusion of the upper lip was correlated with the increases in SNA angle and N-A distance and also with the decrease in SNB angle. The retrusion of the lower lip was correlated with the decrease in N-B distance. The decrease in Sn to A distance was correlated with the increases in SNA, ANB and NAPg angles and N-A distance and also with the decrease in ANS-Gn distance. The increase in Pg' to Pg distance was correlated with the increases in SNA, ANB, NAPg angles and N-A distance. The increase in Si to B distance was correlated with the increases in SNA angle and N-A distance and also with the decreases in N-ANS and ANS-Gn distances. The decrease in Ls to U1 distance was correlated with the increases in SNA and ANB angles and with the increase in N-A distance and with the decreases in N-B and N-Pg distances. The decrease in Li to L1 distance was correlated with the increase in N-A distance. The elongation of the upper lip was correlated with the decrease in ANS-Gn distance. The increase in nasolabial angle was correlated with the decrease in ANS-Gn distance.

CONCLUSION: Maxillary and mandibular soft and hard tissue movements showed significant correlations in horizontal and vertical directions 2.6+/-0.7 years after bimaxillary surgery.