Richard R J Cousley1, Mark Bainbridge1, P Emile Rossouw2. 1. a Orthodontic Department , Peterborough and Stamford Hospitals NHS Foundation Trust , Peterborough , UK. 2. b Division of Orthodontics and Dentofacial Orthopedics , University of Rochester, Eastman Institute of Oral Health , Rochester , NY , USA.
Abstract
OBJECTIVE: Orthognathic wafers may be made using digital model movements and CAD-CAM technology. This paper analysed the accuracy of maxillary movements using this new process. DESIGN: Retrospective study of pre and post-operative cephalograms. PARTICIPANTS: Thirty consecutive orthognathic patients undergoing bimaxillary osteotomies in a UK hospital. METHODS: Jaw movements were planned using cephalometric and Orthoanalyzer™ software. The resultant intermediate and final wafer occlusal relationships were used for wafer fabrication by 3D printing of the inter-occlusal space. Pre- and post-operative lateral cephalograms were compared in terms of maxillary antero-posterior and vertical movements. Statistical analyses including the paired t-test, two-sample t-test and Fisher's exact test. RESULTS: Wide individual variation was observed between the planned and actual movements. Thirteen cases (43%) had a 2 mm discrepancy in at least one variable. Statistically significant differences between the planned and actual maxillary vertical movements were observed for the molar (U6y: p < 0.0001) and anterior maxillary (Ay: p < 0.01) differences. Analysis of a subgroup with primarily impaction movements demonstrated a statistically significant bias towards excessive maxillary advancement (U1x: p < 0.01) and incisor impaction (U1y: p < 0.01) in this group. CONCLUSIONS: This new digital surgical wafer technique achieves a similar level of accuracy to the conventional facebow and model surgery process.
OBJECTIVE: Orthognathic wafers may be made using digital model movements and CAD-CAM technology. This paper analysed the accuracy of maxillary movements using this new process. DESIGN: Retrospective study of pre and post-operative cephalograms. PARTICIPANTS: Thirty consecutive orthognathic patients undergoing bimaxillary osteotomies in a UK hospital. METHODS: Jaw movements were planned using cephalometric and Orthoanalyzer™ software. The resultant intermediate and final wafer occlusal relationships were used for wafer fabrication by 3D printing of the inter-occlusal space. Pre- and post-operative lateral cephalograms were compared in terms of maxillary antero-posterior and vertical movements. Statistical analyses including the paired t-test, two-sample t-test and Fisher's exact test. RESULTS: Wide individual variation was observed between the planned and actual movements. Thirteen cases (43%) had a 2 mm discrepancy in at least one variable. Statistically significant differences between the planned and actual maxillary vertical movements were observed for the molar (U6y: p < 0.0001) and anterior maxillary (Ay: p < 0.01) differences. Analysis of a subgroup with primarily impaction movements demonstrated a statistically significant bias towards excessive maxillary advancement (U1x: p < 0.01) and incisor impaction (U1y: p < 0.01) in this group. CONCLUSIONS: This new digital surgical wafer technique achieves a similar level of accuracy to the conventional facebow and model surgery process.
Entities:
Keywords:
3D printing; Orthoanalyser; Orthognathic wafer; bimaxillary surgery; orthodontic digital models