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Background/purpose: Postoperative skeletal relapse is the most important issue in patients undergoing orthognathic surgery. This study aimed to investigate clinical skeletal relapse (≥2 mm) after mandibular setback surgery (intraoral vertical ramus osteotomy: IVRO) using receiver operating characteristic curve (ROC curve) analysis., Methods: Serial cephalograms of 40 patients with mandibular prognathism were obtained at different time points: (1) before surgery (T1), (2) immediately after surgery (T2), and (3) at least with a 2-year follow-up postoperatively (T3). The menton (Me) was used as the landmark for measuring the amount of mandibular setback and postoperative skeletal relapse. Postoperative stability (T32) was divided into groups A and B by skeletal relapse ≥2 mm and <2 mm, respectively. The area under the ROC curve (AUC) was used to determine the cut-off point for mandibular setback., Results: At the immediate surgical setback (T21), the amount of setback in group A (15.55 mm) was significantly larger than in group B (10.97 mm). Group A (T32) showed a significant relapse (4.07 mm), while group B showed a significant posterior drift (1.23 mm). The amount of setback had the highest AUC area (0.788). The cut-off point was 14.1 mm (T21) that would lead to a clinical relapse of 2 mm (T32)., Conclusion: In IVRO, the postoperative mandibular positions reveal posterior drift and anterior displacement (relapse). The experience of clinical observation and patient perception of postoperative skeletal relapse was ≥2 mm. In the ROC curve analysis, the cut-off point of setback was 14.1 mm., Competing Interests: Declaration of competing interest The authors have no conflicts of interest relevant to this article., (Copyright © 2022 Formosan Medical Association. Published by Elsevier B.V. All rights reserved.)

The aim of this study was to compare how the displacement of the mandibular condyle changed after symmetric or asymmetric mandibular setback surgery using the surgery-first approach (SFA). Patients who underwent mandibular setback surgery using the SFA were selected and divided into a symmetry group (n = 18) with differences of less than 2 mm between the right and left setback, and an asymmetry group (n = 18) with a difference of greater than 2 mm. Cone-beam computed tomography (CBCT)-generated cephalograms were obtained after three-dimensional superimposition of CBCT images taken before surgery (T0), within one week after surgery (T1), and seven months after surgery (T2). The condylar positions were measured. Condylar positional changes according to time were compared between the two groups and correlation analysis was performed. There were significant positional changes in mandibular condyles over time in both groups. However, most of these changes returned to their initial state. In the asymmetry group, there was a greater internal rotation of the mandibular condyle on the lesser setback side. The correlation analysis results revealed that only the setback difference was associated with rotational displacement of the condyle on the lesser setback side at two time points (T1-T0, T2-T0). In the SFA, significant condylar displacement occurred immediately after both symmetric and asymmetric mandibular setback surgery, and the right/left difference in mandibular setback showed a significant positive correlation with rotational displacement. Although more significant rotational displacement of the mandibular condyle was observed after asymmetric mandibular setback surgery, the amount was not large enough to be clinically significant., (Copyright © 2022 Elsevier Masson SAS. All rights reserved.)

Q4: Horizontal changes occur following bilateral sagittal split osteotomy (BSSO) in skeletal class III patients. The aim of this study was to assess the ostoperative changes in intergonial (IG) width and compare them between the positional screw and miniplate fixation methods in BSSO. This study evaluated patients who had mandibular prognathism and underwent BSSO for mandibular setback. Internal fixation was performed bilaterally, either with positional screws in the lateral ramus or with a miniplate. Postero-anterior cephalograms were obtained preoperatively (T1), at 1 month postoperative (T2), and at 6 months postoperative (T3). The IG widths and the alterations in IG width postoperative (T2-T1, T3-T2) were measured. No correlations were observed between the amount of setback and changes at T2 -T1 or T3-T2. The IG width values decreased after mandibular setback and internal fixation with both methods. Statistical analyses showed a significant difference between T3 and T1 in the miniplate group (P=0.045). No significant difference in the postoperative change in IG width (T2-T1 and T3-T2) was found between the two fixation groups. The magnitude of this change was smaller for positional screws when compared to miniplates for fixation. The amount of mandibular setback showed no correlation with postoperative changes in IG width.., (Copyright © 2020 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.)

Introduction: The post-operative facial profile is critical for patients who undergo orthognathic surgery. The present study investigated the improvement in lip appearance (lateral and frontal aspects) following mandibular setback surgery., Material and Methods: Thirty-one patients with mandibular prognathism underwent mandibular setback surgery. Lateral and posteroanterior cephalograms were obtained before surgery (T0) and more than 1 year after surgery (T1). The landmarks (soft and hard tissues) and linear distances were compared by statistical analysis., Results: The lateral cheilion (Ch), point B (B), and pogonion (Pog) were significantly setbackin the horizontal plane: 5.59, 11.49, and 12.35 mm, respectively. In the vertical plane, B and Pog did not move significantly. The Ch moved significantly downward by 3.23 mm on average. The setback ratios of soft tissue/hard tissue, soft tissue of B/B, and soft tissue of Pog/Pog were 0.96. The Ch/Pog ratio was 0.45. The width of the frontal Ch was significantly reduced by 3.17 mm., Conclusions: The relationship between the corresponding soft and hard tissues of the chin was approximately 1. The relationship between the lip corner and chin bone was nearly 50%. The width of the lip corner was also significantly reduced., (Copyright © 2019. Published by Elsevier Masson SAS.)

This study aimed to investigate the postoperative longitudinal skeletal changes and stability following intraoral vertical ramus osteotomies (IVRO) for orthognathic mandibular setback, and the possible risk factors that might affect the stability. A retrospective cohort study was conducted. Lateral cephalograms were analyzed for the predictor (magnitude of setback and adjunctive procedures) and outcome (stability of vertical and horizontal dimensions) variables at six time points. A total of 152 patients (mean age 24.2 years) were included in the study. Following IVRO, the mandible measured at B-point had moved a mean 0.50mm posteriorly at 1 week after the removal of intermaxillary fixation (7 weeks postoperative); this was followed by progressive small anterior relapse. At 2 years postoperative, the mean relapse of the mandible after IVRO measured at B-point was 0.05mm (standard deviation 1.14mm), representing 0.7% of the mean surgical movement. Large setback (>8mm) showed significantly higher relapse compared to small setback (<4mm) at 2 years after surgery (P=0.021). Patients who underwent adjunctive mandibular surgeries other than IVRO showed no significant differences in relapse compared to those who underwent IVRO alone. In conclusion, IVRO for mandibular setback is a stable procedure in the long term, with small relapse of 0.05mm after 2 years., (Copyright © 2017 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.)

The purpose of this study was to elucidate the long-term skeletal and dental stability after combined orthodontic and orthognathic surgical treatment of mandibular prognathism with the intraoral vertical ramus osteotomy (IVRO) as the surgical technique followed by 6 weeks of intermaxillary fixation (IMF). Thirty-six patients were included in the study. Mean age at surgery was 21.6 years. Lateral cephalograms and study casts obtained before the start of treatment (T0), and 8 weeks (T1), 1 year (T2), and 12.5 years (T3) after the operation were evaluated. Mean mandibular setback measured at point B was 8.3mm. Between T1 and T2, a mean anterior relapse of 12% of the setback was observed. Between T2 and T3, the anterior relapse persisted, but decreased to 7% of the setback measured at point B. Despite dental adjustments in both jaws, a statistically significant reduction in overjet was observed during both observation periods. However, the change of the mandible in an anterior direction was small and of minor clinical importance for most of the patients. In conclusion these results indicate that combined orthodontic and orthognathic surgical treatment of mandibular prognathism with the IVRO as the surgical procedure followed by 6 weeks of IMF provides predictable and good long-term clinical results., (Copyright © 2016 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.)

The study objective was to evaluate, through a meta-analysis, the impact on the pharyngeal airway space (PAS) of different orthognathic surgeries for the treatment of the prognathic mandible. An electronic search of three databases and hand searches were carried out up to December 2014. The inclusion criteria were clinical human studies, including randomized controlled trials (RCTs), controlled clinical trials (CCTs), and retrospective studies, with the aim of comparing bilateral sagittal split osteotomy (BSSO) to intraoral vertical ramus osteotomy (IVRO), or one-jaw to two-jaw surgery for the treatment of the prognathic mandible. The PAS changes (anterior-posterior dimensions and cross-sectional area) at the level of the nasopharynx, oropharynx, and hypopharynx were analyzed. A statistically significant difference was found between BSSO and IVRO groups and one-jaw surgery and two-jaw surgery with regard to PAS changes after the treatment of mandibular prognathism. The results of this meta-analysis indicate that BSSO presents less change in the PAS after mandibular setback surgery compared to IVRO. Furthermore, the results of this study suggest that bimaxillary surgery is superior to mandibular setback surgery alone for the correction of the prognathic mandible, particularly in patients with factors predisposing them to the development of breathing problems., (Copyright © 2015 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.)

The extent of three-dimensional soft tissue changes in patients with varied facial skeletal patterns following mandibular setback surgery remains unclear. In this study, we aimed to investigate the postoperative changes in soft tissue chin thickness among mandibular prognathism patients, focusing on those presenting different divergence patterns, such as hyperdivergent and normodivergent patients. Cone-beam computed tomography images were obtained from 56 skeletal Class III patients who underwent only mandibular setback. Based on vertical craniofacial skeletal relationship, patients were divided into normodivergent group (27°37°) group. The three-dimensional displacements of Infradentale (Id), B point (B), and Pogonion (Pog), the soft tissue thickness of Id-Li (Labrale inferius), B-B' (soft tissue B point), and Pog-Pog' (soft tissue Pog point) were measured. Factors influencing the change in soft tissue thickness were investigated. Preoperative B-B' and Pog-Pog' thickness were significantly thinner in the hyperdivergent group than normodivergent group. Postoperative changes in B-B' and Pog-Pog' thickness were significantly larger in the hyperdivergent group than normodivergent group. A significant correlation was found between soft tissue thickness change (B-B' and Pog-Pog') and the preoperative soft tissue thickness and superior movement (B and Pog). Hyperdivergent patients with skeletal class III have thinner preoperative soft tissue thickness (B-B' and Pog-Pog') than normodivergent patients in the preoperation. Postoperative changes in B-B' and Pog-Pog' thickness were significantly larger in the hyperdivergent group than normodivergent group. Postoperative superior movement of B and Pog correlated with postoperative change of soft tissue thickness. [ABSTRACT FROM AUTHOR]

(1) Background: The purpose of this study was to evaluate stability and complications following mandibular setback using intraoral vertical ramus osteotomy (IVRO) and provide an assessment of IMF (Inter-maxillary Fixation) compliance. (2) Methods: This is a retrospective cohort study. It included a total of 39 patients who underwent 78 IVRO for the treatment of mandibular prognathism between 2005 and 2021 at Sheba Medical Center. Radiographic and clinical examinations were performed preoperatively (T0), 3 days post-surgery (T1) and 8 months post-surgery (T2). Measurements of dental and skeletal stability, as well as neurosensory disturbances and TMJ dysfunctions, were statistically analyzed. (3) Results: The mean mandibular setback was 5.6 mm. A relapse of less than 2 mm was observed at T2. A short-term neurological disturbance was reported in 38.46% of the 39 patients, and 17.94% of them showed full recovery by T2. In 21 patients who underwent IVRO without genioplasty, only 14.28% reported long-term sensory disturbance. In addition, when a vertical osteotomy was performed, neurological damage was 174% higher as compared to oblique osteotomy. The IMF compliance rate for the 6 weeks postoperatively was 100%. (4) Conclusions: IVRO is still a relevant and valid technique for the treatment of mandibular prognathism that provides stable results with minimal complications rate. [ABSTRACT FROM AUTHOR]

Abstract Maxillomandibular advancement (MMA) is effective for the treatment of obstructive sleep apnea (OSA). In previous studies, the airway was increased in the anteroposterior and transverse dimensions after MMA. However, the effect of the opposite of mandibular movement (mandibular setback) on the airway is still controversial. Mandibular setback surgery has been suggested to be one of the risk factors in the development of sleep apnea. Previous studies have found that mandibular setback surgery could reduce the total airway volume and posterior airway space significantly in both the one-jaw and two-jaw surgery groups. However, a direct cause-and-effect relationship between the mandibular setback and development of sleep apnea has not been clearly established. Moreover, there are only a few reported cases of postoperative OSA development after mandibular setback surgery. These findings may be attributed to a fundamental difference in demographic variables such as age, sex, and body mass index (BMI) between patients with mandibular prognathism and patients with OSA. Another possibility is that the site of obstruction or pattern of obstruction may be different between the awake and sleep status in patients with OSA and mandibular prognathism. In a case-controlled study, information including the BMI and other presurgical conditions potentially related to OSA should be considered when evaluating the airway. In conclusion, the preoperative evaluation and management of co-morbid conditions would be essential for the prevention of OSA after mandibular setback surgery despite its low incidence.

Background and Aim: Mandibular setback surgery is one of the common treatments in patients with mandibular prognathism. In this surgery, the mandible is placed backward from its original position, and as a result, the soft tissue, tongue, and hyoid bone are slightly displaced, all of which can affect the dimensions of the airway. Given that these changes in the dimensions of the airway can lead to obstructive sleep apnea, it is important to examine these changes and their stability. In this regard, cephalometric radiography can be used, which haslowcost and dose in comparison to 3D radiographs, to examine changes in airway dimensions. The aim of this study was to evaluate the short-term and long-term changes in airway dimensions following mandibular steback surgery with the help of cephalometric radiography. Materials and Methods: The study was conducted by review method. Using the keywords ‘orthognathic surgery,’ ‘mandibular setback,’ ‘Malocclusion angle class III,’ ‘prognathism,’ ‘airway,’ ‘posterior airway space,’ ‘PAS,’ ‘pharyngeal space, ‘hypopharynx, a review of articles in PubMed and Embase databases, Google Scholar, and Cochrane databases was performed. The range of article searches was from 2000 to 2020. Conclusion: The results of studies showed that in the first 6 months after surgery, the dimensions of the airway decrease, but over time, due to the adaptation of the surrounding tissues and relapse after surgery, there is an improvement in the dimensions of the airway; Also, the study of index-related breathing disorders during sleep disorders during sleep showed that this surgery does not necessarily lead to obstructive sleep apnea. Keywords: Orthognathic surgery; Mandibular setback; Malocclusion angle class III; Prognathism; Airway; Posterior airway space; PAS; Pharyngeal space; Hypopharynx.

Maxillomandibular advancement (MMA) is effective for the treatment of obstructive sleep apnea (OSA). In previous studies, the airway was increased in the anteroposterior and transverse dimensions after MMA. However, the effect of the opposite of mandibular movement (mandibular setback) on the airway is still controversial. Mandibular setback surgery has been suggested to be one of the risk factors in the development of sleep apnea. Previous studies have found that mandibular setback surgery could reduce the total airway volume and posterior airway space significantly in both the one-jaw and two-jaw surgery groups. However, a direct cause-and-effect relationship between the mandibular setback and development of sleep apnea has not been clearly established. Moreover, there are only a few reported cases of postoperative OSA development after mandibular setback surgery. These findings may be attributed to a fundamental difference in demographic variables such as age, sex, and body mass index (BMI) between patients with mandibular prognathism and patients with OSA. Another possibility is that the site of obstruction or pattern of obstruction may be different between the awake and sleep status in patients with OSA and mandibular prognathism. In a case-controlled study, information including the BMI and other presurgical conditions potentially related to OSA should be considered when evaluating the airway. In conclusion, the preoperative evaluation and management of co-morbid conditions would be essential for the prevention of OSA after mandibular setback surgery despite its low incidence. [ABSTRACT FROM AUTHOR]

Background: A bilateral sagittal split osteotomy for mandibular prognathism is a very popular and most versatile procedure performed on the mandibular body and ramus. The osteotomy splits the ramus and the posterior body of the mandible sagitally which allows either setback or abvancement. Method: This case report describes management of a skeletal Class III malocclusion with increased reverse overjet. Bilateral sagittal split osteotomy and mandibular setback was performed. Conclusion: The clinical outcome in the present case indicates that the management of skeletal class III malocclusion with a bilateral sagittal split osteotomy with mandibular setback gives promising results [ABSTRACT FROM AUTHOR]

This study aimed to investigate the correlation between the amount of mandibular setback, and the related changes of the tongue area, pharyngeal area, and pharyngeal airflow velocity. Twenty-five patients treated for mandibular prognathism, and serial cephalograms were obtained (T1: preoperation, T2: more than one year postoperation). The postoperative area of the tongue, pharyngeal airway space, and pharyngeal airflow velocity were investigated. Statistical analysis was performed with the Student t-test and Pearson correlation. The amount of mandible setback was significant after surgery (12.8 mm; p < 0.001). The pharyngeal area was significantly reduced 115.5 mm2 (p = 0.046). There was a slight reduction of the tongue area (43.2 mm2; p = 0.305) and an increase of pharyngeal airflow velocity (0.3 m/s; p = 0.133). The Pearson correlation coefficient test showed no statistical significance among the amount of horizontal setback and vertical movement of the mandible, such as the reductions in the tongue area, the pharyngeal airway space, and the increase in pharyngeal airflow velocity. Larger amounts of mandibular setback caused a significant reduction of pharyngeal airway area, but without significant changes of the tongue area and pharyngeal airflow velocity. [ABSTRACT FROM AUTHOR]

Purpose: It has been reported before that the amount of pharyngeal airway space (PAS) significantly decreases following mandibular setback (MS) surgery in patients with mandibular prognathism (MP). Further, MP patients with an anterior open-bite (AOB) presentation may show a larger decrease in PAS compared with those without AOB. However, studies on postoperative PAS changes in MP patients with AOB remain rare. This study sought to evaluate changes in PAS and hyoid bone positioning following MS surgery in MP patients with and without AOB. Patients and methods: Twenty patients who underwent two jaw surgery involving MS movement were included. Patients were divided into a non-AOB group (n = 10; overbite > 2 mm) and an AOB group (n = 10; overbite < − 4 mm). Three-dimensional changes in PAS and hyoid bone positioning were compared and statistically evaluated pre- and postoperatively using computed tomography (CT). Results: The mean magnitude of MS was 6.0 ± 2.8 mm and 5.6 ± 3.2 mm in the non-AOB group and AOB group, respectively. The oropharyngeal volume and upper hypopharyngeal volume were significantly reduced after surgery in both the groups (p = 0.006 and p = 0.003), while the retroglossal cross-sectional area was significantly reduced only in the AOB group (p = 0.028). Although the AOB group showed a larger decrease in PAS, the difference was not statistically significant between the groups. The position of the hyoid bone showed significant posterior and inferior displacement only in the AOB group, while the vertical displacement of the hyoid bone showed a statistically significant difference between the two groups. Conclusion: PAS was significantly decreased after MS in both the groups, while only the AOB group presented a statistically significant reduction in the retroglossal cross-sectional area. Vertical displacement of the hyoid bone showed a statistically significant difference between the groups, while the PAS change was not. Surgeons should be aware of potential postoperative airway problems that may arise when performing MS surgeries. [ABSTRACT FROM AUTHOR]