Three-Dimensional Analysis of Midfacial Soft Tissue Changes After Maxillary Posterior Impaction and Intraoral Vertical Ramus Osteotomy for Mandibular Setback in Class III Patients

Abstract

This study investigated the correlation between the 3-dimensional changes in midfacial soft tissues, including the parasagittal area and maxilla-mandible complex, after Le Fort I maxillary posterior impaction and bilateral intraoral vertical ramus osteotomy (B-IVRO), using cone-beam computed tomography (CBCT). This retrospective study included 22 skeletal Class III patients (6 men and 16 women; mean age 21.6 years) who underwent orthognathic surgery. Three-dimensional CBCT images taken before and 1 year after surgery were superimposed based on the cranial base. Midfacial soft tissues, including those in the parasagittal area (paranasal area, anterior cheek area, lateral cheek area) and midsagittal areas of the face, were evaluated using reconstructed CBCT images. Correlations and the ratios between soft tissue and hard tissue movement were calculated. After surgery, both paranasal areas showed significant forward movement (about 2.0 mm) and the largest upward movement (about 0.15 mm) among the 3 areas. The paranasal areas moved forward with a ratio of 0.5, according to vertical movement of B. Orthognathic surgery using Le Fort I maxillary posterior impaction with B-IVRO mandibular setback results in forward movement of midfacial soft tissues, even though sagittal movement of the maxilla is limited because facial muscles and retaining ligaments pull the redundant soft tissues, which are caused by vertical movement of the maxilla-mandible. This midfacial soft tissue change with maxillary posterior impaction could be advantageous to patients who have paranasal depression and protrusion of the upper lip owing to proclined upper incisors, which are prevalent among Asian Class III patients.

Effect of Le Fort I Maxillary Advancement and Clockwise Rotation on the Anteromedial Cheek Soft Tissue Change in Patients with Skeletal Class III Pattern and Midface Deficiency: A 3D Imaging-Based Prediction Study

“…Therefore, a reliable prediction of the postoperative facial soft tissue change is of paramount importance when appraising orthognathic surgery-related outcomes. Many methods have been adopted for measuring soft tissue responses to underlying skeletal changes, with selected anatomical landmark-based techniques being the most common tools adopted [20][21][22][23][24][25]. However, for example, the closest point color-coded maps method does not allow for the measurement of homologous or corresponding distances.…”

“…However, for example, the closest point color-coded maps method does not allow for the measurement of homologous or corresponding distances. Moreover, most prior studies have focused on the impact of a specific type of surgical maxillary mobilization, i.e., maxillary advancement, on the facial soft tissue change [20][21][22][23][24][25][42][43][44], with the maxillary rotation receiving less attention to date. It is consequently fundamental that further outcome analyses are conducted by implementing a well-delineated 3D imaging-guided methodology based on an accurate quantitative evaluation of facial bone and soft tissue changes after both maxillary advancement and rotational movements.…”

“…A growing body of literature has appraised the relationship between facial bone and soft tissue changes after orthognathic surgery treatment, with most methodological designs being based on 3D landmark-based measurements [20][21][22][23][24][25]. To overcome the drawbacks of landmark-based techniques, a 3D facial region-based volumetric subtraction method was recently developed for the measurement of facial bone and soft tissue changes after orthognathic surgery [26].…”

Cloner 3D photogrammetric facial scanner: Assessment of accuracy in a controlled clinical study

“…A reproducible scanner enables the longitudinal follow-up of treatments that alter facial bone and soft tissue conformation. 5,18 The high intra-and inter-examiner ICC in this study may be explained by the characteristics of the scanner's specific software, which enables standardization of image capture. Before capturing the images, the operator can preview the image and, if necessary, adjust the patient's position with the help of vertical and horizontal lines projected by a positioning laser of the scanner itself.…”

Effect of Botulinum Toxin Injection on Asymmetric Lower Face with Chin Deviation

“…As precisely predicting the post-treatment outcome in facial asymmetry remains challenging, given the diverse patterns of asymmetry and the involvement of both skeletal and soft tissue changes, the asymmetry can remain after the corrective surgery [ 1 , 2 , 9 ]. BoNT can be utilized as an adjunct procedure in such cases.…”