A three – dimensional assessment of the accuracy of lefort 1 osteotomy using patient specific implants

This study evaluated patient specific implant (PSI) accuracy at different maxillary locations during LeFort 1 osteotomy. Twelve patients underwent LeFort 1 osteotomy using PSIs and surgical guides. Deviations between the planned and actual positions were calculated for point A, mid-upper-incisal point, canine cusps, and first molar mesiobuccal cusps across the three axes. Spearman's Rho, Friedman, and Wilcoxon Tests with Bonferroni correction were used for analyses. Maxillary movements in LeFort 1 surgery averaged 1,46 ± 0,09 mm mediolaterally, 3,75 ± 0,23 mm anteroposteriorly, and 1,08 ± 0,17 mm superoinferiorly. The average amounts of deviations were 0,41 ± 0,03 mm (mediolateral), 0,60 ± 0,14 mm (anteroposterior), and 0,45 ± 0,15 mm (superoinferior). Negative correlations existed between planned movement and deviation at point A (superoinferior, P = 0.022) and left first molar (mediolateral, P = 0.045). Posterior teeth showed higher deviations (0.62 ± 0.42 mm) than anterior teeth (0.34 ± 0.30 mm) in the superoinferior direction (P = 0.007). The PSI technique ensures excellent transfer of the desired vertical position of the anterior teeth. Small anterior vertical and posterior transverse movements are more prone to deviations than great movements in the same regions and axes.