Surgical Occlusion Setup in Correction of Skeletal Class III Deformity Using Surgery-First Approach: Guidelines, Characteristics and Accuracy

Yu-Fang Liao,Shu Hsien Lo

doi:10.1038/s41598-018-30124-2

Yu-Fang Liao, Shu Hsien Lo

Open Access

https://doi.org/10.1038/s41598-018-30124-2

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Abstract

The aims of this study were to establish guidelines for the surgical occlusion setup of surgery-first orthognathic surgery, and evaluate the resulting characteristics and accuracy. Skeletal Class III patients (N = 53) underwent Le Fort I osteotomy and bilateral sagittal split osteotomy. Study models before orthognathic surgery were set according to the guidelines. Occlusion was measured and computer-aided surgical simulation was used to evaluate the characteristics and accuracy of the surgical occlusion. The mean age of participants was 25 ± 6 years with 24 males and 29 females. The occlusion was set as positive overjet (4.4 ± 2.0 mm) and overbite (1.4 ± 1.8 mm), Class II or I molar relation, and posterior cross bite (overjet: 4.9 ± 2.0 mm and 4.4 ±1.9 mm, respectively for the right and left second molars) and open bite (overbite: −2.0 ± 1.6 mm and −1.9 ± 1.3 mm, respectively for the right and left second molars). Normal jaw relationship and symmetry were noted after virtual surgery. None of the patients required new occlusal setup. Our data contribute the use of the surgery-first approach for skeletal Class III patients by establishing guidelines for a surgical occlusion setup in three dimensions.

Highlights

The most difficult step for the surgery-first approach is the setup of the transitional occlusion at the time of surgery
We found that the majority of occlusion setups had contact on three segments, and the accuracy of the setup was excellent
Our data contribute the use of the surgery-first approach for skeletal Class III patients by establishing guidelines for a surgical occlusion setup in three dimensions

Summary

Introduction

The most difficult step for the surgery-first approach is the setup of the transitional occlusion at the time of surgery (i.e., surgical occlusion). There are some reports showing guidelines for surgical occlusion setup for www.nature.com/scientificreports/. The guidelines are rather crude; that is, dental occlusion is proposed in the antero-posterior dimension only[8,11,13,14] and, in addition, there are no data available on the occlusal characteristics or accuracy. Accurate surgical occlusion setup is important to avoid severe postoperative occlusal instability, incomplete or excessive skeletal correction, or skeletal asymmetry (i.e., skeletal deformity). 3D virtual simulation process allows us to assess the accuracy of occlusion setup in terms of skeletal deformity. We conducted this study to establish guidelines for surgical occlusion setup, and to investigate the characteristics and accuracy of the surgical occlusion

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