Digital Occlusion Setup Is Quantitatively Comparable with the Conventional Dental Model Approach: Characteristics and Guidelines for Orthognathic Surgery in Patients with Unilateral Cleft Lip and Palate

Background The evolving 3-dimensional computer-based technology revolutionized the field of orthognathic surgery (OGS). Digital occlusion setup for OGS may provide advantages in the planning comparing with the conventional approach based on the manual setup using dental casts, but we are not aware of any study focusing on digital occlusion setup for cleft OGS. The purposes of this study were to compare the conventional and digital occlusion setup approaches and to propose a protocol for digital occlusion setup in unilateral cleft OGS. Methods Thirty consecutive patients with unilateral cleft lip/palate who underwent orthodontic treatment by a single orthodontist and 2-jaw OGS by a single surgeon using 3-dimensional surgical simulation were adopted for analysis. Quantitative data were collected from the dental cast occlusion setup approach (conventional group). A multidisciplinary team combined this quantitative data and established a protocol for digital occlusion setup in cleft OGS. Digital occlusions were set according to this protocol using the images of the 30 patients, and quantitative data were collected accordingly (digital group). The results of 2 groups were compared. All information was reviewed to refine the protocol and define the final guidelines. Results There were no significant differences (all P > 0.05) for all parameters, except midline discrepancy (conventional group > digital group, P < 0.001). The root-mean-square deviation (0.46 ± 0.26 mm) indicated acceptable relationship between the conventional and digital groups. A 6-step protocol for digital occlusion setup in cleft OGS was established: dental midline, overjet/overbite, yaw rotation, pitch rotation, roll rotation, and overall facial skeletal appearance. Conclusions This study shows that digital occlusion setup is quantitatively comparable with the conventional dental model approach and contributes for cleft OGS by establishing a protocol for surgical occlusion setup using digital approach.