Landmark-based versus voxel-based 3D quantitative analysis of bimaxillary osteotomies: a comparative study.

Abstract Purpose To compare the accuracy of landmark-based with a voxel-based 3D analysis to quantify osseous movements of the maxilla and mandible following bimaxillary osteotomies. Materials and Methods CBCT scans of 15 patients who underwent bimaxillary osteotomies were randomly selected from the database. Prior to surgery a CBCT and an individualized 3D virtual surgical plan were made for all patients. During surgery, the mandibular and maxillary segments were positioned as planned by using 3D milled interocclusal splints. One week following surgery, a postoperative CBCT was acquired. All pre- and post-operative CBCT data were rendered in 3D. The 3D virtual head models were superimposed on the cranial base. The 3D surgical movements of the maxilla and mandible were quantified by using a conventional landmark-based 3D cephalometric analyses and by using voxel-based 3D analyses (OGA). This process was performed by the same observer three times. Intra-class correlations and Bland-Altman plots were computed to quantify measurement errors and reproducibility of both methods. Results High intra-class correlation coefficients were found for both methods. The voxel-based analyses yielded a higher correlation concerning the maxilla and distal mandible (r=0.98) compared to the landmark-based cephalometric analyses (r=0.90). Conclusion The use of voxel-based 3D analyses in the quantification of osseous movements was more reliable and reproducible compared to conventional landmark-based 3D analyses.