Accuracy of Combined Osteotomy Guides and Patient-Specific Implants in Le Fort I Segmental Osteotomy Requiring Alveolar Bone Reduction

Background: Segmental Le Fort I osteotomy combined with interdental alveolar bone reduction is a technically challenging procedure, and the accuracy of patient-specific implants (PSIs) in this setting has not been well established. This study aimed to assess the three-dimensional (3D) repositioning accuracy and safety of 3D-printed osteotomy guides used in conjunction with PSIs for this complex surgical procedure. Materials and Methods: This retrospective consecutive case series included 19 patients who underwent segmental Le Fort I osteotomy with alveolar bone reduction in the premolar region. For all patients, 3D-printed osteotomy guides and PSIs were designed using virtual surgical planning (VSP). Postoperative CBCT reconstruction models were superimposed on the VSP models to assess accuracy based on 3D deviations of skeletal and dental landmarks, angular discrepancies, and dental arch morphology. Residual intersegmental alveolar gaps and perioperative complications were also evaluated. Results: Signed and absolute coordinate deviations of all landmarks were within the 2 mm reference margin. Signed coordinate deviations differed significantly among the X-, Y-, and Z-axes (p < 0.05), with the X-axis showing the smallest mean deviation (0.064 ± 0.753 mm). The overall Euclidean spatial error was 1.477 ± 0.519 mm. Anterior maxillary segments exhibited significantly greater sagittal and vertical deviations than posterior segments (p < 0.05). The overall mean residual intersegmental alveolar gap was 0.681 ± 0.153 mm, with the buccal gap at the root apex significantly larger than the corresponding palatal gap (p < 0.05). Two minor dentin injuries occurred, neither of which resulted in clinical pulpal or periodontal complications during the available follow-up. Conclusions: The combined use of osteotomy guides and PSIs facilitates accurate 3D maxillary repositioning in segmental Le Fort I osteotomy involving alveolar bone reduction.