Abstract
Introduction
Orthognathic surgery corrects dentofacial deformities and malocclusion, traditionally relying on hand-articulated stone models for surgical planning. The shift toward digital workflows, utilizing intraoral scanning and virtual surgical planning (VSP), offers potential improvements in efficiency and reproducibility. There are benefits to understanding occlusal differences between stone models and digital occlusions to support the adoption of purely digital planning in orthognathic surgery.
Objectives
This study investigates whether digitally articulated occlusions are equivalent to hand-articulated occlusions in orthognathic surgery planning.
Methods
A comparative study, of 52 retrospective orthognathic patient cases (26 skeletal Class II and 26 skeletal Class III), assessed the equivalence of planned post-surgical occlusions set digitally in contrast to those articulated by hand. Comparison of translational (canine, molar, midline) and rotational (pitch, roll, yaw) measurements by previously validated methods was undertaken by three clinician investigators. Equivalence was assessed within a 2 mm margin via two one-sided t-tests (TOST). A panel analysis was used to assess variability between clinician investigators.
Results
Results demonstrate equivalence for canine, midline, and rotational measurements (p < 0.05), with an average translational difference of 1.78 mm. However, equivalence was not achieved at molar sites, whose measurements were influenced by occlusal factors such as the presence of large lateral open bites. Subgroup analysis showed consistent equivalence for Class II and III occlusions at canine and midline sites, with greater variability in Class III molar measurements. Variability between clinician investigators was minimal, except for specific molar and pitch measurements influenced by individual technique.
Conclusions
These findings support that digital planning workflows are at least as accurate, if not more, than traditional methods for occlusal planning in orthognathic surgery. Adoption of digital articulation in VSP aligns with trends toward digital workflows, but highlights the need for software enhancements to address challenges to the user experience and mitigation of human error. Recommendations include improved software design, such as incorporation of artificial intelligence aids, and standardised digital planning training to facilitate broader clinical application.