In Vivo Accuracy of a New Digital Planning System in Terms of Jaw Relation, Extent of Surgical Movements and the Hierarchy of Stability in Orthognathic Surgery

Abstract

This retrospective cohort study compares the virtual planned and postoperative jaw positions in patients undergoing orthognathic surgery. Surgery was virtually planned with the Digital Münster Model Surgery system (DMMS). Primary outcome: Spatial difference in the maxillo-mandibulo relation between virtual planning and postoperative result. Secondary outcome: Possible relationship between the measured differences and surgical movements as well as the postoperative stability according to Proffit. Ninety female and sixty-one male patients were included in the study. The average translation errors were 0.54 ± 0.50 mm (anteroposterior), 0.37 ± 0.33 mm (mediolateral), and 0.33 ± 0.28 mm (superoinferior). Orientation errors were 0.86 ± 0.79 degrees (yaw), 0.54 ± 0.48 degrees (roll), and 0.90 ± 0.72 degrees (pitch). The surgical procedures do not differ with respect to their error sizes. Maxilla forward and class II maxilla up with mandible forward are the most precise procedures. Most significant differences were found in the anteroposterior direction, whereby the extent of the surgical movement has no effect on the magnitude of the error. The process of planning with the DMMS followed by surgery is highly accurate and shows error values well below the clinically accepted limit of two millimeters in translation and four degrees in rotation.

The Position of the Virtual Hinge Axis in Relation to the Maxilla in Digital Orthognathic Surgery Planning—A k-Means Cluster Analysis

“…Articulators have been used for decades in orthognathic surgery planning with excellent clinical success [11,29]. The measured error rates of conventional plaster planning are within one millimeter, on average [30].…”

“…The decision to use a planning system based on a physical articulator, a virtual articulator or a CBCT is not a decision relating to accuracy, as all systems provide similar results [11] and remain below the general accepted clinical error size of two millimeters in translation [26] and four degrees in rotation [27].…”

“…Although planning in orthognathic surgery has conventionally always been performed in the articulator, new methods do not use the virtual articulator approach, but focus on simulating osteotomies using CBCT [11]. The majority of these methods require the support of commercial vendors [12].…”

“…The angle α between the upper occlusal plane (uOP) and the AOP; 2. the vertical distance (AxV) between the arbitrary hinge axis (Ax) and its projection (Ax') onto the occlusal plane; 3. the horizontal distance (AxH) between Ie and Ax'. These values are sufficient to align a maxillary scan in a virtual space in the same way as in the conventional SAM articulator with physical facebow and bite fork [11,13].…”

Das Münsteraner Konzept zur Therapie der ektodermalen Dysplasien im Kontext der wissenschaftlichen Literatur

“…Nach dem Münsteraner Konzept werden alle Patient*innen, die eine chirurgische Lagekorrektur benötigen, mit dem Digital Münster Model Surgery (DMMS) System 61 62 virtuell geplant ( Abb. 17 und 18 ).…”