Successful New Dental Implant Installation in a Healed Site of Medication-Related Osteonecrosis of the Jaw: A Case Report.

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.

A new rationale for preservation of the mandibular third molar in orthognathic patients with missing molars.

Controversies exist regarding the need for prophylactic extraction of mandibular third molars in patients who plan to undergo orthognathic surgery. An 18-year-old male patient was diagnosed with mandibular prognathism and maxillary retrognathism with mild facial asymmetry. He had a severely damaged mandibular first molar and a horizontally impacted third molar. After extraction of the first molar, the second molar was protracted into the first molar space, and the third molar erupted into the posterior line of occlusion. The orthognathic surgery involved clockwise rotation of the maxillomandibular complex as well as angle shaving and chin border trimming. Patients who are missing or have damaged mandibular molars should be monitored for eruption of third molars to replace the missing posterior tooth regardless of the timing of orthognathic surgery.

Total Intravenous Anesthesia in a Malignant Hyperthermia-Susceptible Patient with Klinefelter Syndrome Undergoing Orthognathic Surgery.

ABSTRACT: 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.

NELL-1 Increased the Osteogenic Differentiation and mRNA Expression of Spheroids Composed of Stem Cells.

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 ß-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 > 0.05). There was statistically higher alkaline phosphatase activity in the 10 ng/mL group compared with the unloaded control on Day 7 (p < 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 < 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.

Preemptive intravenous iron therapy versus autologous whole blood therapy for early postoperative hemoglobin level in patients undergoing bimaxillary orthognathic surgery: a prospective randomized noninferiority trial.

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<ype=my&rtype=my .

Methylsulfonylmethane Induces G1 Arrest and Mitochondrial Apoptosis in YD-38 Gingival Cancer Cells.

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 P21Waf1/Cip1 and P27Kip1 genes and down-regulated expression of cyclin D1 (CCND1) and CDK4. Moreover, treatment with MSM induced apoptosis and up-regulation of BAX in YD-38 cells. In accordance, the expression of the BCL-2 and BCL-XL, were inhibited, indicating the role of mitochondria in MSM-induced apoptosis. Analysis of mitochondrial integrity showed a loss of mitochondrial potential with an increased level of cytochrome c in the cytosol compared to mitochondria. Active CASPASE-3 (CASP3) was also observed, confirming that MSM-induced apoptosis is caspase-mediated.

Analgesic effects of nefopam in patients undergoing bimaxillary osteotomy: A double-blind, randomized, placebo-controlled study.

PURPOSE: 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. MATERIAL AND METHODS: 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. RESULTS: 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). CONCLUSION: 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. ( TRIAL REGISTRATION: ClinicalTrials.gov (NCT 01461031)).

Stability After Bilateral Sagittal Split Osteotomy With Rigid Internal Fixation in Surgery-First Approach.

PURPOSE: 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. PATIENTS AND METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

Vertical eruption patterns of impacted mandibular third molars after the mesialization of second molars using miniscrews.

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.

Tannic acid inhibits the Jak2/STAT3 pathway and induces G1/S arrest and mitochondrial apoptosis in YD-38 gingival cancer cells.

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 <10% of all head and neck squamous cell carcinomas was studied in the YD-38 cell line. The main goal was to modulate the Jak2/STAT3 pathway using TA and to induce cell cycle arrest and apoptosis in GSCC. TA treatment induced G1 arrest and apoptosis in YD-38 cells. Molecular analysis revealed that TA inhibits Jak2/STAT3 pathway by preventing their expression as well as phosphorylation. This inhibition of STAT3 phosphorylation prevented the nuclear translocation and DNA binding capability of STAT3. Together with the inhibition of transcriptional regulatory function of STAT3, TA inhibited the expression of G1 phase modulators CDK-4, CDK-6, cyclin D1 and cyclin E. It is also evidenced that TA exerted an intense activation of p21Waf1/Cip1, p27Kip1 and p53 genes confirming its role in G1 phase inhibition. Additionally, upon treatment with TA, the expression of mitochondrial pore factors Bax, Bcl-2 and Bcl-XL were changed. We observed inhibition of Bcl-2 and an increase in mitochondrial localization of Bax leading to the loss of mitochondrial membrane potential, resulting in the release of cytochrome c to the cytosol. In addition, we perceived the activation of caspases upon TA treatment. Specific inhibition of caspase protected the cells from TA induced apoptosis. Taken together, this study reveals that TA significantly inhibits the Jak2/STAT3 signaling pathway and induces G1 arrest and mitochondrial apoptosis in YD-38 cells.

Bone formation on biomimetic calcium phosphate-coated and zoledronate-immobilized titanium implants in osteoporotic rat tibiae.

PURPOSE: Coating prostheses with calcium phosphate (CaP) can boost ossification and provide an appropriate vehicle for drug delivery. In this study, CaP coating was performed using a biomimetic method, and zoledronate (ZOL) was incorporated to promote peri-implant bone formation in an osteoporotic environment. MATERIALS AND METHODS: Twenty female 8-week-old rats were ovariectomized to induce osteoporosis. Twelve weeks later, the animals were randomly separated into four groups representing different ZOL concentrations in the immersion solution: 0 (control), 8, 80, and 800 µg/mL. Surface-treated implants were inserted in both tibiae, and the rats were sacrificed 8 weeks after implantation. Specimens were retrieved for histomorphometric and microcomputed tomographic analyses. RESULTS: A thin CaP coating was formed on the surface of the titanium implants, and ZOL was successfully incorporated into the structure of the biomimetic CaP coating. There were significant differences between the groups with regard to bone volume, whereas bone-implant contact comparisons did not yield any significant differences. The microstructural results clearly illustrated the positive effect of ZOL loading on the implants, as compared to the controls. CONCLUSIONS: The data suggest that biomimetic CaP coating followed by bisphosphonate immobilization is effective in improving bone quality and preserving bone volume around dental implants; therefore, this technique may be beneficial for osteoporosis patients.

Evaluation of minimal versus conventional presurgical orthodontics in skeletal class III patients treated with two-jaw surgery.

PURPOSE: 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). MATERIALS AND METHODS: 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. RESULTS: 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 (P < 0.01) 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. CONCLUSIONS: 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.

Combined multisegmental surgical-orthodontic treatment of bialveolar protrusion and chin retrusion with severe facial asymmetry.

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.

Osteogenic potential of adult stem cells from human maxillary sinus membrane by Simvastatin in vitro: preliminary report.

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 µM 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.

Assessment of asymmetry in a normal occlusion sample and asymmetric patients with three-dimensional cone beam computed tomography: a study for a transverse reference plane.

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.

Change in bite force and electromyographic activity of masticatory muscle in accordance with change of occlusal plane.

PURPOSE: The purpose of the present study was to evaluate effects of occlusal plane on masticatory function (biting force, masticatory muscle activity, biting efficiency) after bimaxillary orthognathic surgery. PATIENTS AND METHODS: The subjects of the present study consisted of a group of 55 adults who had undergone bimaxillary surgery more than 6 months earlier. Lateral cephalographs, bite force, and electromyographic measurements of the anterior temporal [EMG(t)] and masseter muscles [EMG(m)] were recorded before and after bimaxillary surgery. Statistical analyses were performed. RESULTS: In the increased occlusal plane group, the frequency of decreased EMG(t) was significantly high. The frequency of increased EMG(t) was also significantly high in the decreased occlusal plane group. A negative correlation was found between the postoperative occlusal plane angle and the biting force efficiency change. No significant difference was found between the group that moved from an abnormal to a normal range and the group that moved from a normal to an abnormal range. The occlusal plane change was significantly greater in the decreased EMG(t) group than in the increased EMG(t) group. CONCLUSIONS: The value of EMG(t) was related to the changes in the occlusal plane, and the biting efficiency was affected by the postoperative occlusal plane angle. However, normalization of the occlusal plane might not play a major role in masticatory function.

Postoperative condylar position by sagittal split ramus osteotomy with and without bone graft.

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.

Alveolar bone loss around incisors in surgical skeletal Class III patients.

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.

Three-dimensional finite element analysis of stress distribution and displacement of the maxilla following surgically assisted rapid maxillary expansion.

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.

Adult stem cells derived from human maxillary sinus membrane and their osteogenic differentiation.

PURPOSE: 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. MATERIALS AND METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.