Dataset Information

Three-dimensional surgical accuracy between virtually planned and actual surgical movements of the maxilla in two-jaw orthognathic surgery.

ABSTRACT:

Objective

To investigate the three-dimensional (3D) surgical accuracy between virtually planned and actual surgical movements (SM) of the maxilla in twojaw orthognathic surgery.

Methods

The sample consisted of 15 skeletal Class III patients who underwent two-jaw orthognathic surgery performed by a single surgeon using a virtual surgical simulation (VSS) software. The 3D cone-beam computed tomography (CBCT) images were obtained before (T0) and after surgery (T1). After merging the dental cast image onto the T0 CBCT image, VSS was performed. SM were classified into midline correction (anterior and posterior), advancement, setback, anterior elongation, and impaction (total and posterior). The landmarks were the midpoint between the central incisors, the mesiobuccal cusp tip (MBCT) of both first molars, and the midpoint of the two MBCTs. The amount and direction of SM by VSS and actual surgery were measured using 3D coordinates of the landmarks. Discrepancies less than 1 mm between VSS and T1 landmarks indicated a precise outcome. The surgical achievement percentage (SAP, [amount of movement in actual surgery/ amount of movement in VSS] × 100) (%) and precision percentage (PP, [number of patients with precise outcome/number of total patients] × 100) (%) were compared among SM types using Fisher's exact and Kruskal-Wallis tests.

Results

Overall mean discrepancy between VSS and actual surgery, SAP, and PP were 0.13 mm, 89.9%, and 68.3%, respectively. There was no significant difference in the SAP and PP values among the seven SM types (all p > 0.05).

Conclusions

VSS could be considered as an effective tool for increasing surgical accuracy.

SUBMITTER: Hong M

PROVIDER: S-EPMC7500567 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:Background: Favourable occlusal interdigitation and an optimized position of the mandibular condyle after surgery are essential for obtaining favourable results. The position of the condyle is determined during the operation. However, it is difficult to maintain the condyle's original position post-surgery despite the efforts of the surgeons. Indeed, a degree of rotation of the condyle is unavoidable, since it is difficult to verify whether the condyle is positioned correctly during surgery. Purpose: To maximize contact between the bone segments, the condyle was rotated around the vertical axis using surgical simulations. We examined changes to the condyle-fossa relationship after comparing virtual surgery to actual surgery. Methods: From 2015 to 2017, 20 patients were diagnosed with skeletal malocclusion and participated in computer-aided surgical simulation before undergoing orthognathic surgery. In the simulation, the mandibular condyles were rotated around the vertical axis, and the proximal segments were fixed to the distal segments using a customized miniplate and positioning device during actual surgery. This study investigated the relationship between the condyle and fossa using cone-beam computed tomography for several different time periods (preoperative (T0), virtual surgery (Tv), postoperative three days (T1) and one year (T2)). Results: The coronal and sagittal view exhibited significant differences in the mean values between T1and T0, Tv, and T2 for all joint spaces. As a result of the distance, the mean value of T2 in both the superior joint space (JS) and the lateral JS was significantly higher than that of Tv. In contrast, the mean value of Tv in the medial JS was significantly higher than that of T2. Moreover, the mean value of T2 on the axial plane was significantly larger than the values of Tv and T1. The mean value of T0 was also significantly larger than those of Tv and T1, and the mean value of Tv was larger than that of T1. Although the condyle was rotated, it exhibited a tendency to return to its preoperative position. There was no statistically significant difference in functional evaluation between T0 and T2. Conclusion: Our method of using yaw control for the condyle during virtual surgery and transferring this technique to the actual surgery can improve the conventional surgical technique by positioning the proximal segment in a pre-planned position, thus achieving optimal results.