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The purpose of this case report was to present a rare clinical case of successful new dental implant installation in the site of previously healed medication-related osteonecrosis of the jaw (MRONJ). An 80-year-old female patient with history of oral bisphosphonate (BP) therapy presented with pain and swelling of gingiva in the right posterior mandible. One of the 3 implants placed 15 years ago in the right mandibular posterior area was removed 6 months before the visit to our hospital, which led to worsening of the symptoms. After clinical and radiographic examination, the patient was diagnosed with stage 2 MRONJ. Along with antibiotic therapy, the patient underwent surgical intervention via sequestrectomy and removal of the remaining 2 implants. Adequate soft and hard tissue healing without any complications and signs of recurrence was confirmed, and implant installation with simultaneous bone grafting and prosthesis fabrication were done in the explantation sites of MRONJ. By the 7-year follow-up, no implant failure has been observed, and installation of implants was successful in the previously healed MRONJ site. Dental implant installation is possible in a patient with history of failed implant due to MRONJ. However, a careful treatment planning is needed before implantation in a previously healed site of MRONJ to reduce the potential risks of MRONJ recurrence and implant failure.

To ensure that orthognathic surgery is successful, functional aspects such as mastication, pronunciation, swallowing and aesthetic factors must be considered. For successful orthognathic surgery, the orthodontist and the surgeon must constantly study and discuss accurate facial analysis, presurgical orthodontics, choice of appropriate surgical methods, and postsurgical orthodontics. In this article, we will discuss the team approach for successful orthodontic treatment and orthognathic surgery, establishing close cooperation between the orthodontist and surgeon.

A patient with Klinefelter syndrome and skeletal Class III malocclusion experienced a malignant hyperthermia-like reaction while undergoing orthognathic surgery. The patient fully recovered after prompt diagnosis and management, and surgery was reattempted under total intravenous anesthesia. The patient was discharged without any anesthetic complications and was satisfied with the surgical results. This is the first described case of a malignant hyperthermia-like event in a patient with Klinefelter syndrome. Total intravenous anesthesia may be safely administered in malignant hyperthermia-susceptible patients who require orthognathic surgery.

To ensure that orthognathic surgery is successful, functional aspects such as mastication, pronunciation, swallowing and aesthetic factors must be considered. For successful orthognathic surgery, the orthodontist and the surgeon must constantly study and discuss accurate facial analysis, presurgical orthodontics, choice of appropriate surgical methods, and postsurgical orthodontics. In this article, we will discuss the team approach for successful orthodontic treatment and orthognathic surgery, establishing close cooperation between the orthodontist and surgeon.

There has been an increased public interest in orthognathic surgery that has led to many additional surgeries being performed in response to patients' aesthetic needs. Often procedures such as genioplasty, mandibuloplasty, malarplasty, paranasal augmentation could be done to enhance the aesthetic effects of orthognathic surgery. With these procedures, it is very important to establish clear communication between the patient and surgeon to reduce misunderstandings and to increase patient's satisfaction after surgery. In this article, we will discuss cases where additional aesthetic surgeries were performed in connection with orthognathic surgery to demonstrate ways that patient facial beauty can be improved.

Background and objectives: NELL-1 is a competent growth factor and it reported to target cells committed to the osteochondral lineage. The secreted, osteoinductive glycoproteins are reported to rheostatically control skeletal ossification. This study was performed to determine the effects of NELL-1 on spheroid morphology and cell viability and the promotion of osteogenic differentiation of stem cell spheroids. Materials and Methods: Cultures of stem cell spheroids of gingiva-derived stem cells were grown in the presence of NELL-1 at concentrations of 1, 10, 100, and 500 ng/mL. Evaluations of cell morphology were performed using a microscope, and cell viability was assessed using a two-color assay and Cell Counting Kit-8. Evaluation of the activity of alkaline phosphatase and calcium deposition assays involved anthraquinone dye assay to determine the level of osteogenic differentiation of cell spheroids treated with NELL-1. Real-time quantitative polymerase chain reaction (qPCR) was used to evaluate the expressions of RUNX2, BSP, OCN, COL1A1, and β-actin mRNAs. Results: The applied stem cells produced well-formed spheroids, and the addition of NELL-1 at tested concentrations did not show any apparent changes in spheroid shape. There were no significant changes in diameter with addition of NELL-1 at 0, 1, 10, 100, and 500 ng/mL concentrations. The quantitative cell viability results derived on Days 1, 3, and 7 did not show significant disparities among groups (p &gt, 0.05). There was statistically higher alkaline phosphatase activity in the 10 ng/mL group compared with the unloaded control on Day 7 (p &lt, 0.05). A significant increase in anthraquinone dye staining was observed with the addition of NELL-1, and the highest value was noted at 10 ng/mL (p &lt, 0.05). qPCR results demonstrated that the mRNA expression levels of RUNX2 and BSP were significantly increased when NELL-1 was added to the culture. Conclusions: Based on these findings, we conclude that NELL-1 can be applied for increased osteogenic differentiation of stem cell spheroids.

Background Previous studies have reported the efficacy and safety of intravenous (IV) iron therapy during the perioperative period as an alternative and adjunct to allogeneic blood transfusion. Preemptive IV iron therapy provides noninferior hemoglobin levels on postoperative day (POD) 1 compared to autologous whole blood therapy (AWBT) in healthy patients who had undergone bimaxillary orthognathic surgery. Methods This was a prospective, patient-randomized, noninferiority trial. After excluding 2 patients, 64 patients were divided into two groups: the IV iron therapy group (patients received IV iron infusion 4 weeks before surgery; n = 32) and the AWBT group (2 units of autologous whole blood were collected 4 and 2 weeks before surgery; n = 32). The primary outcome was hemoglobin level on POD 1 and the prespecified noninferiority limit was − 1 g/dL. Results Baseline data were comparable, including hemoglobin and iron levels, between the two groups. Immediately before surgery, the levels of hemoglobin, iron, and ferritin were higher in the IV iron group than in the AWBT group. The mean treatment difference (iron group—whole blood group) in hemoglobin level on POD 1 between the two groups was 0.09 (95% CI = − 0.83 to 1.0). As the lower limit of the 95% CI (− 0.83) was higher than the prespecified noninferiority margin (δ = − 1), noninferiority was established. On POD 2, the hemoglobin level became lower in the iron group, which eventually led to greater requirement of allogeneic blood transfusion compared to the whole blood group. However, the iron group did not require allogeneic blood transfusion during or early after surgery, and the whole blood group showed continuously higher incidence of overt iron deficiency compared to the iron group. Conclusion As collection of autologous whole blood caused overt iron loss and anemia before surgery and intraoperative transfusion of whole blood was not able to prevent the occurrence of persistent iron deficiency after surgery, IV iron therapy was found to have potential benefits for iron homeostasis and subsequent erythropoiesis in healthy patients early after bimaxillary orthognathic surgery. Trial registration: Clinical Research Information Service, Republic of Korea, approval number: KCT0003680 on March 27, 2019. https://cris.nih.go.kr/cris/search/search_result_st01_kren.jsp?seq=15769&sLeft=2&ltype=my&rtype=my.

Case report: Subcutaneous emphysema is a rare but serious side effect of dental and oral surgery procedures. It is characterized by air being forced underneath the tissue, leading to swelling, crepitus on palpation, and with potential to spread along the fascial planes to the periorbital, mediastinal, pericardial, and/or thoracic spaces. A wide range of causes has been documented for the origin of subcutaneous emphysema during dental treatment including: crown preparations, endodontic therapy, extractions, as well as oral surgery procedures. The patient was a 58-year-old woman who presented to the Seoul St. Mary’s hospital emergency department with a chief complaint of facial edema, dyspnea and chest discomfort after periodontal treatment using an air-flow equipment in local dental clinic. Oxygen therapy and intravenous injection of steroid and antihistamine were done. It was noted that the patient had pain and swelling on left lower molar region, pus discharging on same site. Severe edema was observed on periorbital region to neck with heatness. An audible crepitus sound was heard during palpation. Antibiotic therapy was done, as symptom suggesting dental abscess is observed. After injection of antibiotics, symptom was relieved, but she felt chest discomfort continuously. CT scan with contrast depicted confluent and extensive soft tissue emphysematous changes involving face and deep neck spaces and pneumomediastinum. The patient was referred to thoracic surgery department, oxygen therapy was decided continuously. After 10 h, patient’s chief complaint was resolved. After 1 week, all symptoms disappeared and follow-up neck CT scan finding was disappearance of edema and pneumomediastinum.

Tannic acid (TA), is a potent anti-oxidant, showing anti-proliferative effects on numerous cancers. The ability of TA to induce proliferation inhibition on the rare tumor, gingival squamous cell carcinoma (GSCC), comprising

Angioedema is defined as self-limited, localized swelling. The swelling is asymmetric, non-pitting, and non-tender. Common locations of swelling include periorbital area, lips, tongue, extremities, and bowel wall. A 54-year-old woman visited our hospital with the clinical complaint of left maxillary swelling. Swelling of the left maxillary area was diffuse and temperature of the involved area was normal. No infectious source was found on panoramic radiography and cone-beam computed tomography. After considering the patient's medical history and assessing clinical examination, we suspected angioedema and administered corticosteroid only. In the oral and maxillofacial area, proper diagnosis and prompt treatment of angioedema is important because angioedema of the tongue or larynx may lead to airway obstruction or a life-threatening condition.

Gingival squamous cell carcinoma is a rare form of cancer that accounts for less than 10% of all head and neck cancers. Targeted therapies with natural compounds are of interest because they possess high efficacy with fewer side-effects. Methylsulfonylmethane (MSM) is an organic sulfur-containing compound with anticancer activities. The main goal of this study was to induce proliferation inhibition and apoptosis in the metastatic YD-38 cell line. MSM up-regulated expression of P21

OBJECTIVE: To characterize symmetrical features of patients with facial asymmetry and thus to find the most reliable horizontal reference lines easily used in three-dimensional images. The hypothesis was that there is a difference in the location of bilateral landmarks of the upper skull between the normal occlusion sample and skeletal Class III patients with asymmetry. MATERIALS AND METHODS: Group 1 (normal occlusion sample) was composed of 20 Korean adults with normal occlusion and no noticeable asymmetry. Groups 2 through 4 were selected from patients who were diagnosed as skeletal Class III malocclusion and grouped according to the extent of asymmetry (group 2: symmetric mandible, no maxillary cant; group 3: asymmetric mandible, no maxillary cant; group 4: asymmetric mandible, more than 4 mm maxillary cant measured at maxillary first molars). Three-dimensional cone beam computed tomography images were taken before treatment, and bilateral landmarks of the skull were located and their vertical and horizontal differences compared. RESULTS: No statistically significant difference was noted in the position of bilateral landmarks between groups, except for AG (P < .05). AG showed significant differences in vertical dimension (P < .001) and in horizontal dimension (P < .0001) between groups. The mean of the difference was clearly greatest at FM. CONCLUSIONS: The hypothesis is rejected. All groups had a similar pattern of asymmetry in the upper third of the face. Therefore, the transverse reference line of the bilateral Z or orbitale may be used even in patients with severe asymmetry of the maxilla with reference to the clinical photos.

The prevalence of gastroesophageal reflux disease (GERD) has increased recently in Asia-Pacific countries. However, little is known about its prevalence and clinical characteristics in GERD patients with atypical symptoms in Asia. The aim of this study was to investigate the clinical characteristics of GERD in patients who had laryngeal symptoms in Korea. Data were gathered retrospectively from patients who presented with atypical symptoms, such as throat discomfort, globus pharyngeus, hoarseness, and chronic cough. They underwent a 24-hour ambulatory intraesophageal pH monitoring and filled in a validated reflux questionnaire. Overall, 128 patients (36 men and 92 women) with laryngeal symptoms were included. Of these 128, 43 patients (34%) had erosive esophagitis or pathological reflux from 24-hour ambulatory pH monitoring, and 24 (19%) had a positive Bernstein test or positive symptom index from 24-hour pH monitoring. Sixty-one patients (48%) had no evidence of reflux esophagitis on upper endoscopy and pathological acid reflux on 24-hour pH monitoring. Fifty-six patients (44%) had weekly heartburn or regurgitation. Typical symptoms and dyspepsia were significantly more common in patients with GERD who had laryngeal symptoms than non-GERD. Fifty-two percent of patients had laryngeal symptoms that were associated with GERD. The presence of typical reflux symptoms and dyspepsia are risk factors for GERD in patients who present with laryngeal symptoms.

Background Small intestinal bacterial overgrowth (SIBO) is expected in postgastrectomy patients; however, its role has not been clarified. This study was to estimate the prevalence of SIBO and investigate the clinical role of SIBO in postgastrectomy patients. Methods This prospective study involved 76 patients who underwent gastrectomy for early gastric cancer with no evidence of recurrence. An H2–CH4 breath test with oral glucose challenge test was performed to diagnose SIBO and dumping syndrome. Sigstad dumping questionnaires, serum glucose, hematocrit and pulse rate were simultaneously monitored for every 30 min for 3 hours. Key Results There were significant differences in SIBO between the postgastrectomy patients and controls (77.6%vs 6.7%, P

Objective: To test the hypothesis that there is no difference in the vertical alveolar bone levels and alveolar bone thickness around the maxillary and mandibular central incisors in surgically treated skeletal Class III malocclusion patients. Materials and Methods: The study sample comprised 20 Korean patients with skeletal Class III malocclusion with anterior crossbite and openbite (9 male, 11 female, mean ages 24.1). Three-dimensional cone beam computed tomography images were taken at least 1 month before the orthognathic surgery, and sagittal slices chosen at the labio-lingually widest point of the maxillary and mandibular right central incisor were evaluated. Measurement of the amount of vertical alveolar bone levels and alveolar bone thickness of the labial and lingual plate at the root apex was made using the SimPlant Pro 12.0 program. Results: The mandibular incisors showed reduced vertical alveolar bone levels than the maxillary incisors, especially on the lingual side. The alveolar bone thickness was significantly greater on the lingual side in the maxillary incisors, whereas the mandibular incisors exhibited an opposite result (P < .05). The percentage of vertical bone loss to root length showed a statistically significant difference between the upper labial and lower labial alveolar bone and also between the upper lingual and lower lingual alveolar bone, showing more bone loss in the lower incisors (P < .001). Conclusions: The hypothesis is rejected. For the skeletal Class III patients undergoing orthognathic surgery, special care should be taken to prevent or not aggravate preexisting alveolar bone loss in the anterior teeth, especially in the mandible.

Alteration of cadherin expression is associated with the loss of cellular differentiation, the acquisition of an invasive phenotype and a poor prognosis in many types of cancer. This study aimed to evaluate the immunoreactivity of E-, P- and N-cadherins (cad) in oral squamous cell carcinoma and to correlate their expression with clinicopathological features and clinical outcome. The interaction between the cadherins was also investigated.A total of 71 tissue samples were examined by immunohistochemical methods on paraffin sections using specific antibodies.In the primary lesions and lymph node metastases, the immunoreactivity of E-cad was reduced and P-cad was over-expressed, but the expression of N-cad was negative (p0.001, 0.01 and 0.05, respectively). The reduced primary E-cad expression was related to the invasion pattern and lymph node metastasis (p=0.046 and 0.037, respectively). However, the expression of cadherins did not appear to differ significantly in relation to the histological grade, invasion, tumour size, stage of oral SCC or tumour recurrence. A much greater reduction in the expression of E-cad was found in the positive N-cadherin group (p=0.008). Nonetheless, cadherin expression was not significantly associated with failure-free survival or overall survival in this experiment subset.The reduced E-cad expression and the aberrant N-cad expression are closely associated with each other in oral cancer cases, and this suggests that cadherin switching from E. cad to N. cad may play a critical role in cancer development and metastasis.

Objective: To investigate (1) whether vertical eruption of impacted third molars improves after mesialization of second molars and (2) what factors affect the vertical eruption of impacted third molars when space caused by missing molars is successfully closed by mesialization of the second molar using miniscrews. Materials and Methods: The treatment group (Group 1) included 52 patients who had (1) missing mandibular first molars (ML-6) or missing deciduous mandibular second molars (ML-E), (2) initially impacted mandibular third molars, and (3) successful space closure of the edentulous area with orthodontics. Panoramic radiographs at start of treatment (T1) and at time of space closure (T2) were collected. The control group (Group 2) included 46 nonedentulous patients with impacted mandibular third molars without molar protraction treatment. Panoramic radiographs with similar T1/T2 treatment times were selected. Nine measurements were obtained regarding horizontal available space, vertical eruption, and third molar angulation. Results: Third molars erupted vertically an average of 2.54 mm in Group 1 compared with 0.41 mm in Group 2. Age, gender, Nolla stage, and angle of the third molars did not show significant correlations with the vertical change of the impacted third molars, whereas the depth of third molar impaction and available space showed significant correlations. Conclusions: Impacted mandibular third molars vertically erupt as a result of uprighting with mesialization of the second molar, and vertical eruption is affected by the initial vertical location of impacted third molars and available space.

Many studies have examined the postoperative analgesic effects of nefopam in various settings. However, although nefopam is expected to be useful in bimaxillary osteotomy, no published data are available.We divided 42 patients into nefopam [n = 21, nefopam 20 mg intravenous (i.v.) 30 min before surgery, followed by an i.v. infusion (5 mg/h) beginning immediately postoperatively for 24 h] and control [n = 21, normal saline] groups. Then we compared the analgesic efficacy, side effects, and degree of patient satisfaction with postoperative analgesia.Pain was lower in the nefopam group than in the controls in the recovery room [4.6 (3.0-6.0) vs. 6.0 (5.5-7.0), median (interquartile range), P = 0.002] and on the ward. Fewer patients in the nefopam group required rescue analgesics, and the degree of patient satisfaction was significantly higher in the nefopam group (P 0.001). There were no significant differences in other side effects between the groups. However, the control group showed more sedation 1 h postoperatively (P = 0.009).Nefopam is an effective analgesic in bimaxillary osteotomy in that it can reduce the use of opioids and nonsteroidal anti-inflammatory drugs, thereby reducing the side effects of conventional analgesics. (ClinicalTrials.gov (NCT 01461031)).

The purpose of this study was to evaluate the stability of bilateral sagittal split ramus osteotomy (BSSO) setback with rigid internal fixation in a surgery-first approach (SFA) for patients with skeletal Class III malocclusion.Twenty-seven consecutive patients with skeletal Class III malocclusion treated with BSSO with the SFA were included in the study. Lateral cephalograms were taken and traced before surgery and 1 and 6 months after surgery. Cephalometric measurements were compared using repeated-measures analysis of variance. A P value less than or equal to .05 was considered significant.The study included 9 men (age, 25.7 ± 2.9 yr) and 18 women (age, 26.6 ± 4.2 yr). Treatment time was 8.4 ± 1.5 months. Horizontally, there were no meaningful anteroposterior changes of the pogonion and B point during the postsurgical period (0.9 and 0.6 mm, respectively). Vertically, the pogonion showed superior movement after surgery (2.4 mm) without major postsurgical change (0.6 mm). The B point showed major superior movement after surgery (2.3 mm) and during the postsurgical period (1.2 mm). The inclination of the lower incisor was increased labially during the postsurgical period (2.4°), although this was not statistically important.In the present study, there was no major horizontal relapse for any variable (1 mm). Vertically, all variables showed no meaningful changes during the postsurgical period except the B point showed 1.2 mm of superior displacement. BSSO with rigid fixation using the SFA seems to be an effective and predictable procedure in patients with skeletal Class III malocclusion.

Laryngeal granulomas are the most common late complication of endotracheal intubation in adults when intubation-related subglottic granulomas result from severe trauma. Airway manipulation during intuba tion and the smaller dimension of the female larynx could be contributing factors to intubation granuloma. Seventy to 90% of all intubation-related laryngeal granulomas reported have been in female patients. 2

J Korean Assoc Oral Maxillofac Surg 2013;39:150-155) Objectives: The objective of this study is to determine the adequate concentration and to evaluate the osteogenic potential of simvastatin in human maxillary sinus membrane-derived stem cells (hSMSC). Materials and Methods: Mesenchymal stem cells derived from the human maxillary sinus membrane were treated with various concentrations of simvastatin. The adequate concentration of simvastatin for osteogenic induction was determined using bone morphogenetic protein (BMP-2). The efficacy of osteogenic differentiation of simavastatin was verified using osteocalcin mRNA, and the mineralization efficacy of hSMSCs and simvastatin treatment was compared with alkaline phosphatase and von Kossa staining. Results: Expression of BMP-2 mRNA and protein was observed after three days and was dependent on the concentration of simvastatin. Expression of osteocalcin mRNA was observed after three days in the 1.0 μ M simvastatin-treated group. Mineralization was observed after three days in the simvastatin-treated group. Conclusion: These results suggest that simvastatin induces the osteogenic potential of mesenchymal stem cells derived from the human maxillary sinus membrane mucosa.

The purpose of this study was to compare changes in hard and soft tissues and the treatment efficacy of 2-jaw surgery combined with nonextraction treatment for skeletal Class III malocclusion in patients who received minimal presurgical orthodontics (MPO) versus those who received conventional presurgical orthodontics (CPO).Thirty-two patients (16 in each group) with skeletal Class III malocclusion who underwent 2-jaw surgery were included in the study. Serial lateral cephalometric films were traced at 4 stages: before treatment (T0), before surgery (T1), 1 month after surgery (T2), and at debonding (T3). Cephalometric measurements and treatment duration were compared using independent t test and Mann-Whitney U test.After the presurgical treatment phase, the angle between the lower incisor axis and mandibular plane, overjet, and soft tissue pogonion to the vertical reference line showed larger changes (P0.01) in the CPO group, whereas the pogonion to the horizontal reference line showed larger changes (P.05) in the MPO group. In the postsurgical phase (T2 to T3), there were no significant differences between the 2 groups. Total treatment duration was significantly shorter in the MPO group.There were no significant differences between the MPO and CPO groups in the hard and soft tissue cephalometric variables. The MPO group had a shorter total treatment time. It is therefore recommended that clinicians consider these results when selecting MPO as a treatment option for accurate diagnosis and treatment planning of Class III surgical patients.

LeFort I osteotomy, anterior segmental osteotomy, bilateral sagittal split ramus osteotomy, and genioplasty are frequently used methods for correcting facial deformities. However, in patients with an abnormally shaped maxilla or mandible, more complex surgical techniques or multiple combinations must be considered for improved esthetic results. This article presents a patient with bialveolar protrusion, mandibular prognathism, chin retrusion, a long face, and severe facial asymmetry. A combination of LeFort I asymmetric impaction, anterior segmental osteotomy, and 3-piece segmentation of the maxilla, and bilateral sagittal split ramus osteotomy, anterior segmental osteotomy, genioplasty advancement, and angle shaving in the mandible were conducted simultaneously. In patients with complicated deformities that cannot be classified by simple conventional classification methods, multisegmental osteotomy can be an option for improved esthetic results.

To investigate the method and conditions of isolation and proliferation of multipotent mesenchymal stem cells (MSCs) from human maxillary sinus membrane in vitro and to induce osteogenic differentiation directly for identification.A human maxillary sinus membrane specimen was collected in aseptic conditions from an orthognathic surgery patient and cultured. The cells at passage three were sorted by flow cytometry and treated with osteogenic differentiation media. To determine the osteogenic potential of these cells, the authors analyzed alkaline phosphatase (ALP) expression, mineralization of extracellular matrix, and osteocalcin expression; staining with alizarin red and von Kossa and reverse-transcriptase polymerase chain reaction were also performed.Maxillary sinus membrane-derived cells were positive for STRO-1 and CD105 and negative for CD34. After 7 days, ALP began to be expressed. After 21 and 28 days, most cells showed expression of ALP. Mineralization of the extracellular matrix was observed and, after 21 and 28 days, most of the cells showed mineralization. After 7 days, the osteocalcin gene was expressed; this expression was strongest on the 28th day.The results suggest that there are MSCs in human maxillary sinus membrane tissue, which can be differentiated into osteoblasts under osteogenic induction. This indicates that maxillary sinus membrane may be a useful source of MSCs for cell therapy.

Purpose The purpose of the present study was to determine how the condylar position is affected by the bone graft in the intersegmental space created by sagittal split ramus osteotomy. Patients and Methods We compared the position of the condyle after sagittal split ramus osteotomy, without the bone graft (control group, n = 30) and with the bone graft (study group, n = 30) using computed tomography with a 2-mm thickness. Using 3-dimensional images and a 3-dimensional computer program, the pre- and postoperative displacement and rotation of the condyle in the axial (rotation and mediolateral movement of the condyle) and sagittal plane (anteroposterior and superoinferior movement of the condyle and rotation of the proximal segment) were measured. In addition, the relationship of the amount of rotation and backward movement of the mandible and the change in the condylar position was analyzed. For the statistical analysis, the t test (P = .05) and Wilcoxon rank sum test were used. Results No statistically significant differences were found in any of the measurements of the 2 groups. Nevertheless, the mediolateral movement (P = .051) showed a relatively greater apparent difference, although the difference was not statistically significant. The condylar displacement had no relationship to the rotation of the mandible. However, the condylar displacement in relation to the amount of backward movement of the mandible was significant, especially when it was greater than 10 mm of setback. Conclusions Using a bone graft in the intersegmental gap of a sagittal split ramus osteotomy is considered an effective clinical method to secure the desirable intersegmental position because it helps to maintain the space with ease. Especially in cases with greater than 10-mm setback of the mandible, it prevents excessive condylar displacement.

Summary Purpose The aim of this study was to investigate the displacement and stress distributions during surgically assisted rapid maxillary expansion under different surgical conditions. Materials and methods 3-dimensional finite element model of a maxilla with a Hyrax appliance was constructed and an expansion force of 6000 grams was applied using the expansion screw. According to the surgical procedures, 5 groups including a control group without surgery (Group I) were simulated. The experimental groups were as follows; Group II (Le Fort I osteotomy), Group III (Le Fort I osteotomy and paramedian osteotomy), Group IV (Le Fort I osteotomy and pterygomaxillary separation), and Group V (Le Fort I osteotomy, paramedian osteotomy, and pterygomaxillary separation). Results Displacement of the maxilla gradually increased from Group 1 to Group 5 in all three planes of space, indicating that combination of the Le Fort I osteotomy with paramedian osteotomy and pterygomaxillary separation produce greatest displacement of the maxilla. By surgical relief, the stress exerted on anchor teeth was significantly reduced. Conclusion The results suggested that the combination of Le Fort I and paramedian osteotomy with pterygomaxillary separation is an effective procedure for increasing the expansion of the maxilla with lower side effects caused by excessive stresses around the anchor teeth.

Objective The purpose of this study was to evaluate the influence of orthognathic surgery on articular disc position and temporomandibular disorder symptoms of skeletal class III patients by means of clinical and radiographic evaluation of the temporomandibular joint. Study design Thirty-six patients with skeletal class III malocclusion, who were treated at Kangnam St. Mary’s Hospital between January 2005 and January 2006, were evaluated by clinical examination and pre- and postoperative magnetic resonance imaging. Results The change of articular disc position after mandibular setback surgery by means of sagittal split ramus osteotomy was not statistically significant, but it tended to be positioned posteriorly. Conclusion It can be suggested that orthognathic surgery does not significantly change the position of the articular disc.

Introduction: To evaluate the 3-dimensional changes in the pharyngeal airway of skeletal class III patients after bimaxillary surgery. Materials and Methods: The study sample consisted of 18 Korean patients that had undergone maxillary setback or posterosuperior movement and mandibular bilateral sagittal split osteotomy setback surgery due to skeletal class III malocclusion (8 males, 10 females; mean age of 28.7). Cone beam computed tomography was taken 1 month before and 6 months after orthognathic surgery. Preoperative and postoperative volumes of the nasopharyngeal, oropharyngeal, and laryngopharyngeal airways and minimum axial areas of the oropharyngeal and laryngopharyngeal spaces were measured. Moreover, the pharyngeal airway volume of the patient group that had received genioplasty advancement was compared with the other group that had not. Results: The nasopharyngeal and laryngopharyngeal spaces did not show significant differences before or after surgery. However, the oropharyngeal space volume and total volume of pharyngeal airway decreased significantly (P Conclusion: The results indicate that bimaxillary surgery decreased the volume and the minimum axial area of the oropharyngeal space. Advanced genioplasty did not seem to have a significant effect on the volumes of the oropharyngeal and laryngopharyngeal spaces.

Objectives: This study sought to evaluate fixation methods and determine the best method for the postoperative stabilization of maxillary osteotomy. For our analysis we performed a three-dimensional finite element analysis of stress distribution on the plate, screw, and surrounding bone, as well as displacement onto the plate. Materials and Methods: We generated a model using synthetic skull scan data; an initital surface model was changed to a solid model using software. Modified anterior segmental osteotomy (using Park’s method) was made using the program, and four different types of fixation methods were used. An anterior load of 100 N was applied on the palatal surface of two central incisors. Results: The Type 1 (L-shaped) fixation method gave stresses of 187.8 MPa at the plate, 45.8 MPa at the screw, and 15.4 MPa at the bone around the plate. The Type 2 (I-shaped) fixation method gave stresses of 186.6 MPa at the plate, 75.7 MPa at the screw, and 13.8 MPa at the bone around the plate. The Type 3 (inverted L-shaped) fixation method gave stresses of 28.6 MPa at the plate, 29.9 MPa at the screw, and 15.3 MPa at the bone around the plate. The Type 4 (I-shaped) fixation method gave stresses of 34.8 MPa at the plate, 36.9 MPa at the screw, and 14.9 MPa at the bone around the plate. The deflection of the plates for the four fixation methods was 0.014 mm, 0.022 mm, 0.017 mm, and 0.018 mm, respectively. Conclusion: The Type 3 (inverted L-shaped) fixation method offers more stability than the other fixation methods. We therefore recommend this method for the postoperative stabilization of maxillary osteotomy.

Objectives: This study evaluated a range of fixation methods to determine which is best for the postoperative stabilization of a mandibular osteotomy using three-dimensional finite element analysis of the stress distribution on the plate, screw and surrounding bone and displacement of the lower incisors. Materials and Methods: The model was generated using the synthetic skull scan data, and the surface model was changed to a solid model using software. Bilateral sagittal split ramus osteotomy was performed using the program, and 8 different types of fixation methods were evaluated. A vertical load of 10 N was applied to the occlusal surface of the first molar. Results: In the case of bicortical screws, von-Mises stress on the screws and screw hole and deflection of the lower central incisor were minimal in type 2 (inverted L pattern with 3 bicortical repositioning screws). In the case of plates, von-Mises stress was minimal in type 8 (fixation 5 mm above the inferior border of the mandible with 1 metal plate and 4 monocortical screws), and deflection of the lower central incisor was minimal in types 6 (fixation 5 mm below the superior border of the mandible with 1 metal plate and 4 monocortical screws) and 7 (fixation 12 mm below the superior border of the mandible with 1 metal plate and 4 monocortical screws). Conclusion: Types 2 and 6 fixation methods provide better stability than the others.