Horizontal changes in the condylar head after sagittal split ramus osteotomy with bent plate fixation

金沢大学医薬保健研究域医学系Objective: The purpose of this study was to evaluate the horizontal changes in the condylar head with bent plate fixation after sagittal split ramus osteotomy (SSRO) with and without a Le Fort I osteotomy. Study design: Of 47 Japanese patients with mandibular prognathism, 24 underwent SSRO and 23 underwent SSRO in combination with a Le Fort I osteotomy. A 3-5-mm gap was made between the proximal and distal segments, and a bent plate was fixed with 4 screws in each side of the mandible. The angle of the condylar long axis, as well as the anteroposterior and mediolateral displacement of the condylar head were assessed preoperatively and postoperatively by computerized tomography (CT). Results: There was no significant difference in reduction in mandibular length between SSRO alone and SSRO with Le Fort I on the axial view of a 3-dimensional CT. There were no significant differences between pre- and postoperative horizontal changes in the condylar long axis or in the anteroposterior and mediolateral displacement of the condylar head, although the length of the proximal segment in SSRO with Le Fort I osteotomy was significantly shorter than in SSRO alone (P < .05). Conclusion: These results suggest that the use of a bent plate for SSRO does not change preoperative angle or position significantly in setback surgery, regardless of the addition of Le Fort I osteotomy. © 2008 Mosby, Inc. All rights reserved.This article has not been published yet

Assessment of the Relationship Between the Recovery of Maximum Mandibular Opening and the Maxillomandibular Fixation Period After Orthognathic Surgery

金沢大学大学院医学系研究科がん細胞学Purpose: The purpose of this study was to evaluate the differences in the recovery of maximum mandibular opening (MMO), and the relationship between MMO and the maxillomandibular fixation (MMF) period after sagittal split ramus osteotomy (SSRO) and intraoral vertical ramus osteotomy (IVRO), with and without Le Fort I osteotomy. Patients and Methods: Sixty-eight patients with diagnosed mandibular prognathism with or without asymmetry were divided into 4 groups (SSRO, IVRO, SSRO with Le Fort I osteotomy, and IVRO with Le Fort I osteotomy). MMO and the MMF period were measured preoperatively and at 1, 3, 6, 12, and 18 months after surgery. The differences among surgical procedures and the relationship between MMO and the MMF period were examined statistically. Results: In relation to time-dependent changes in MMO, there were no significant differences among the groups. There were significant positive correlations between MMO and the MMF period from 1 month to 6 months after surgery. However, there were no significant correlations at 12 and 18 months after surgery. Conclusion: This study suggests that there were no significant differences between single-jaw surgery and double-jaw surgery in terms of postoperative time-dependent changes in the recovery of MMO. However, the MMF period was associated with the recovery of MMO. © 2008 American Association of Oral and Maxillofacial Surgeons

A comparative CT evaluation of pharyngeal airway changes in class III patients receiving bimaxillary surgery or mandibular setback surgery

金沢大学大学院医学系研究科がん細胞学Objective: The purpose of this study was to compare the morphologic changes of the upper airway space in Class III patients who underwent mandibular setback or bimaxillary surgery (maxillary advancement and mandibular setback) by computed tomography at 2 levels: soft palate and base of tongue. Methods: The sample consisted of 47 subjects in 2 groups who had been diagnosed as having Class III skeletal deformities and had been treated by mandibular setback or bimaxillary surgery (maxillary advancement and mandibular setback). Anteroposterior, lateral, and cross-sectional area dimensions of the airway at the level of soft palate and base of tongue were measured pre- and postoperatively on computed tomography images. Results: Anteroposterior dimensions of the airway decreased in both groups (P .05). Conclusions: This study suggests that bimaxillary surgery can prevent narrowing of the upper airway in the correction of Class III deformities in comparison with mandibular setback surgery used as the sole treatment. Computed tomography was valuable in determining the effects of surgical treatment on pharyngeal airway dimensions. © 2008 Mosby, Inc. All rights reserved

Changes in the Duration of the Chewing Cycle in Patients With Skeletal Class III With and Without Asymmetry Before and After Orthognathic Surgery

金沢大学医薬保健研究域医学系Purpose: The purpose of this study was to examine the changes in the chewing rhythm before and after mandibular ramus osteotomy in patients with prognathism with and without asymmetry. Patients and Methods: We divided 12 men and 22 women with mandibular prognathism into groups on the basis of symmetry and osteotomy procedure. The duration of the chewing cycle was recorded preoperatively and postoperatively. The duration of the chewing cycle and coefficient of variation were compared between groups, and the differences were analyzed statistically. Results: No significant differences in each of 3 phases of the chewing cycle and total duration were found between groups on the basis of symmetry or osteotomy procedure. However, there were significant differences between the preoperative and postoperative coefficients of variation for the undeviated side in the asymmetry group (P = .0037) and in the group undergoing sagittal split ramus osteotomy (P = .0166). Conclusion: This study suggests that surgical orthodontic treatment does not significantly change the duration of the chewing cycle. © 2009 American Association of Oral and Maxillofacial Surgeons

The effect of mandibular setback or two-jaws surgery on pharyngeal airway among different genders

金沢大学医薬保健研究域医学系Cephalometric studies show significant gender differences in the size of the pharyngeal airway space. This study aimed to investigate and compare morphologic changes after mandibular setback or two-jaws surgery on the pharyngeal airway in men and women using computed tomography (CT). The sample included 34 women and 13 men diagnosed with Class III skeletal deformities, who had been treated by mandibular setback or bimaxillary surgery (maxillary advancement and mandibular setback). Anteroposterior, lateral and cross-sectional area dimensions of the airway, at the level of soft palate and base of tongue, were measured pre- and postoperatively on CT images. In the mandibular setback group, the anteroposterior and cross-sectional area of the pharyngeal airway at the level of the soft palate and base of tongue were significantly reduced for men or women (P .05). This study suggests that oropharyngeal airway measurements, important for airway patency, do not demonstrate sex dimorphism. © 2009 International Association of Oral and Maxillofacial Surgeons