Effect of self-setting α-tricalcium phosphate between segments for bone healing and hypoaesthesia in lower lip after sagittal split ramus osteotomy.

AIMS: The aim of this study was to evaluate hypoaesthesia of the lower lip and bone formation using self-setting α-tricalcium phosphate (Biopex(®)) between the proximal and distal segments following sagittal split ramus osteotomy (SSRO) with bent absorbable plate fixation. SUBJECTS AND METHODS: The subjects were 40 patients (80 sides) who underwent bilateral SSRO setback surgery. They were divided into a Biopex(®) group (40 sides) and a control group (40 sides). The Biopex(®) was inserted into the anterior part of the gap between the segments in the Biopex(®) group. Trigeminal nerve hypoaesthesia in the region of the lower lip was assessed bilaterally using the trigeminal somatosensory-evoked potential (TSEP) method. Ramus square, ramus length, and ramus width, the square of the Biopex(®) at the horizontal plane under the mandibular foramen were assessed preoperatively, immediately after surgery, and 1year postoperatively by computed tomography (CT). RESULTS: The mean measurable period and standard deviation were 9.3±15.7weeks in the control group, 5.3±8.3weeks in the Biopex(®) group, and there was no significant difference. Ramus square after 1year was significantly larger than that prior to surgery and new bone formation was found between the segments in both groups (P<0.05). In the Biopex(®) group, the square of the Biopex(®) after 1year was significantly smaller than that immediately after surgery (P<0.05). CONCLUSION: This study suggested that inserting Biopex(®) in the gap between the proximal and distal segments was useful for new bone formation and it did not prevent the recovery of lower lip hypoaesthesia after SSRO with bent absorbable plate fixation.

Expression of urokinase-type plasminogen activator/urokinase-type plasminogen activator receptor and maspin in oral squamous cell carcinoma: Association with mode of invasion and clinicopathological factors.

It is well documented that the binding of urokinase-type plasminogen activator (uPA) to its receptor (uPAR), which has been implicated in cancer invasion and metastasis, is regulated by several inhibitors such as maspin. In this study, we investigated the interrelationship between clinicopathologic findings and expression of uPA, uPAR and maspin in oral squamous cell carcinoma (OSCC) to elucidate the participation of maspin in the uPA/uPAR system in the malignant behavior of OSCC. Using immunohistochemical techniques to examine the expression levels of uPA, uPAR and maspin in 54 cases of OSCC, we also compared the clinicopathologic features of OSCC with the expression levels of each. Moreover, we examined the expression of uPA, uPAR and maspin in six cell lines derived from OSCC using reverse transcriptase-polymerase chain reaction (RT-PCR) and Western blotting. uPA and uPAR showed a positive correlation with the mode of cancer invasion; conversely maspin showed a negative correlation with the mode of invasion. Multivariate analysis revealed that only two factors (N-category and uPA+/uPAR+/maspin- expression pattern) were significant and independent variables with relative risks of 3.84 and 2.52, respectively. In particular, tumors exhibiting an expression pattern of uPA+/uPAR+/maspin- were highly malignant and were associated with the worst survival rate (5-year overall survival rate, 29.4%), while tumors with an expression pattern, uPA-/uPAR-/Μaspin+, showed the most favorable survival rate (5-year overall survival rate, 77.8%). In vitro, lower expression of maspin was also noted in the cell lines derived from grade 4D OSCC, which exhibited a stronger invasive potential than the cells lines derived from the other grades of OSCC, while uPA and uPAR demonstrated an expression trend opposite to maspin. These results indicate that uPA, uPAR and maspin expression patterns may be useful markers for evaluating the clinical course or prognosis of OSCC patients.

Expression form of p53 and PCNA at the invasive front in oral squamous cell carcinoma: correlation with clinicopathological features and prognosis.

BACKGROUND: Abnormalities in cell-cycle-controlling genes are important in the malignant transformation and proliferation of tumors. Among these genes, the tumor suppressor gene p53 is the most notable, and its mutations provide an indicator of tumor progression and prognosis. Proliferating cell nuclear antigen (PCNA) is a highly conserved nuclear protein that is expressed during cell replication and DNA repair. This study examined the expression of p53 and PCNA at the invasive front of oral squamous cell carcinomas (OSCC) by immunohistochemical staining, and investigated the relationship of these proteins to clinicopathological findings and prognosis. METHODS: Fifty-nine biopsy cases of OSCC were examined by immunohistochemical staining. Clinicopathological data were gathered and patient survival was analyzed. RESULTS: The p53 labeling index (p53-LI) and PCNA labeling index (PCNA-LI) were examined at the invasive front of the tumors. A high p53-LI (p53+) was observed in 17 of the 59 cases (28.8%) and a high PCNA-LI (PCNA+) was observed in 28 of the 59 cases (47.5%). Among the modes of cancer invasion, many of the p53+/PCNA+ cases could be confirmed as highly invasive cancer (P < 0.05). In addition, the p53+/PCNA+ cases showed a high risk of tumor recurrence compared with the other expression forms, and patients with p53+/PCNA+ had a worse prognosis than those with the other expression forms. High labeling indices of p53 and PCNA are associated with poor prognosis in patients with OSCC. CONCLUSION: We suggest that it is important to investigate the expression of p53 and PCNA at the invasive front of OSCC.

Skeletal stability after mandibular setback surgery: comparisons among unsintered hydroxyapatite/poly-L-lactic acid plate, poly-L-lactic acid plate, and titanium plate.

PURPOSE: The purpose of this study is to compare the time-course changes in condylar long-axis and skeletal stability after sagittal split ramus osteotomy (SSRO) with an unsintered hydroxyapatite (u-HA)/poly-L-lactic acid (PLLA) plate, PLLA plate, or titanium plate. PATIENTS AND METHODS: Of 60 Japanese patients diagnosed with mandibular prognathism, 20 underwent SSRO with a u-HA/PLLA plate system, 20 underwent SSRO with a PLLA plate system, and 20 underwent SSRO with a conventional titanium plate system. The time-course changes in condylar long-axis and skeletal stability were assessed by use of axial, frontal, and lateral cephalograms. RESULTS: Compared with the u-HA/PLLA group, the titanium group showed a significantly greater change in the right condyle angle between initially and 1 month (P = .0105) and intercondylar axes angle between 1 and 3 months (P = .0013). The PLLA group showed a significantly greater change than the titanium group (P = .0043) and u-HA/PLLA group (P = .0002) in terms of ramus inclination between 1 and 3 months; however, there were no significant differences among the 3 groups in the other measurements for each time interval. CONCLUSION: This study suggests that there are no significant differences in postoperative time-course changes among a u-HA/PLLA plate system, PLLA plate system, and conventional titanium plate system.

Assessment of bone healing after Le Fort I osteotomy with 3-dimensional computed tomography.

PURPOSE: The purpose of this study was to examine bone healing after Le Fort I osteotomy in Class III patients. PATIENTS AND METHODS: The study group consisted of 18 Japanese patients with mandibular prognathism with and without asymmetry, maxillary retrognathism or open bite. A total of 36 sides were examined. Le Fort I osteotomy was performed without a pterygoid osteotome, with an ultrasonic curette used to remove interference at the pterygomaxillary region. Titanium plates (Universal Mid-face fixation module, Stryker, Freiburg, German) were used for four patients, absorbable plates (poly-L-lactic acid (PLLA): NEOFIX(®), Gunze, kyoto, Japan) were used for four patients and other absorbable plates (uncalcined and unsintered hydroxyapatite and poly-L-lactic acid (uHA/PLLA): super FIXSORB(®)MX, Takiron Co. Ltd, Osaka, Japan) were used for 10 patients, in the same manner. Postoperative computed tomography (CT) was analyzed for all patients pre-operatively and 1 year postoperative. The anterior and lateral areas between the maxillary segments were measured with 3-dimensional (3D) CT. Bone healing at the pterygomaxillary region was also assessed. RESULTS: There were no significant differences in the area of bone defect healing among the plate types. The areas of bone defect after 1 year were significantly smaller than that immediately after surgery on the right side (p=0.0145) and left side (p=0.0010) in the frontal view and right side in the lateral view (p=0.0118). Bone healing at the pterygomaxillary junction was found in all cases without artificial pterygoid plate fracture. Fourteen of 22 sides with artificial pterygoid plate fracture by an ultrasonic curette showed bone continuity between the pterygoid plate and posterior part of maxilla. CONCLUSION: This study suggested that bony healing could occur in spaces between the segments of maxilla and pterygomaxillary regions as well as the region of the anterior and lateral walls in the maxilla, but it is not always complete within 1 year after Le Fort I osteotomy.

Use of self-setting α-tricalcium phosphate for maxillary sinus augmentation in rabbit.

PURPOSE: The purpose of this study was to histologically and immuno-histochemically evaluate tissue changes in the maxillary sinus after bone screw implantation and maxillary sinus augmentation using self-setting α-tricalcium phosphate (α-TCP; BIOPEX(®)-R) in rabbit. STUDY DESIGN: Adult male Japanese white rabbits (n=15, 12-16 weeks, 2.5-3 kg) were used. The sinus lift was made from the nasal bone of a rabbit. Bone screws (Dual top auto-screw(®)) were implanted into the nasal bone, and after BIOPEX(®)-R was implanted into the left elevated space (operated side) an atelocollagen sponge (ACS: Teruplug(®)) was implanted into the right elevated space (control side). The rabbits were sacrificed at 4, 12 and 24 weeks postoperatively, and formalin-fixed specimens were embedded in acrylic resin. The specimens were stained with hematoxylin and eosin. For immune-histochemical analysis, the specimens were treated with bone morphogenetic protein-2 (BMP-2) antibodies. Finally, these were evaluated microscopically. RESULTS: Tight bonding without fibrous tissue continued between the bone screw and BIOPEX(®)-R, and the rigidity of the bone screw in the nasal bone was retained for 24 weeks in all cases. The area ofnew bone formation increased gradually on both sides; however, there was no significant difference between both sides at 4, 12 and 24 weeks. The number of BMP-2-stained cells on the experimental side was significantly larger than that on the control side after 4 weeks (P=0.0361). CONCLUSION: This study suggested the usefulness of self-setting α-TCP (BIOPEX(®)-R) to maintain the rigidity of implanted bone screws from an early period, and the result of BMP-2 expression suggested that BIOPEX(®)-R could have bone-conductive activity in the maxillary sinus augmentation.

Stress change on the temporomandibular joint in mandibular prognathism subjects with asymmetry after orthognathic surgery.

The purpose of this study was to evaluate changes in stress on the temporomandibular joint (TMJ) in 80 Japanese subjects (21 males and 59 females, mean age 23.7 years) with mandibular prognathism, with and without asymmetry after orthognathic surgery using the rigid bodies spring model (RBSM). The asymmetric group consisted of 40 subjects whose Mx-Md midline was more than 3 degrees. The remaining 40 subjects formed the symmetric group. The geometry of the stress analysis model was based on frontal cephalograms of the subjects. Menton (Me), the centre point of occlusal force on a line connecting the bilateral buccal cusps of the second molars, and the most lateral, superior, and medial points on the condyle were plotted on a computer display and stress on the condyle was calculated with the two-dimensional RBSM program, Fortran. The degree (force partition) of the resultant force, the direction (angulation), and the displacement (X, Y) of each condyle were calculated and the horizontal displacement (u), the vertical displacement (v), and rotation displacement (theta) of the mandibular body at Me were calculated pre- and post-operatively. The data was analysed using paired and unpaired t-tests. For the vertical (v) and rotational (theta) displacement, the post-operative value was smaller than the pre-operative value (v: P < 0.001, theta: P = 0.0063) in the asymmetric group. For angulation and the X-component, the post-operative value was smaller than that pre-operatively on the deviated (angulation: P = 0.0074, X-component: P = 0.0003) and non-deviated (angulation: P = 0.0024, X-component: P = 0.001) side in the asymmetric group. However, there was no significant difference between the pre- and post-operative value for any parameter in the symmetric group. These findings suggest that surgical correction of mandibular prognathism, with and without asymmetry, could induce an improvement in stress balance on the TMJ in the frontal aspect.

Position of mandibular canal and ramus morphology before and after sagittal split ramus osteotomy.

PURPOSE: The purpose of this study was to evaluate changes in the mandibular canal and ramus morphology before and after a sagittal split ramus osteotomy. PATIENTS AND METHODS: The subjects were 30 patients (60 sides) with mandibular prognathism who had undergone bilateral sagittal split ramus osteotomy setback surgery. The mandibular canal position and ramus morphology were measured at the 3 horizontal planes under the mandibular foramen level (level A), 1 cm lower than level A (level B), and 2 cm lower than level A (level C) preoperatively and 1 year postoperatively by computed tomography. RESULTS: Postoperative ramus width, lateral distance, lateral marrow distance, and canal length were significantly larger than the preoperative values at the foramen, 1 cm lower, and 2 cm lower. The mandibular canal completely contacted the lateral cortex without lateral bone marrow in 6 sides (10%) in levels A and B and 4 sides (6.7%) in level C preoperatively and 6 sides (10%) in level C postoperatively. CONCLUSION: This study suggested that postoperative mandibular canal position was located more posteriorly and the postoperative lateral bone marrow became thicker compared with the preoperative state.

Multicenter phase 2 study of induction chemotherapy with docetaxel and nedaplatin for oral squamous cell carcinoma.

PURPOSE: To determine the clinical and hisotological efficacy and toxicities of induction chemotherapy with docetaxel (DOC) and nedaplatin (CDGP) for oral squamous cell carcinoma (OSCC) in the preoperative setting. METHODS: A total of 30 patients with locally advanced but operable OSCC were enrolled. Combination induction chemotherapy consisted of DOC 60 mg/m2 followed by CDGP 100 mg/m2. RESULTS: All patients received one cycle of chemotherapy. In the clinical assessment, ten patients achieved partial response for an overall response rate of 33.3% (95% CI, 16.4-50.2%). Histological assessment of surgical specimens showed an overall response rate of 56.6% (95% CI, 38.9-74.3%). Although severe neutropenia was observed in 90% of patients, only one patient (3.3%) experienced severe infection. Toxicities associated with this regimen did not interfere with planned radical surgery. CONCLUSIONS: A single cycle of preoperative combination chemotherapy with DOC and CDGP showed moderate histological activity with an acceptable safety profile for the planned radical surgery. Further studies testing more cycles before surgery might be more appropriate.

Assessment of ramus, condyle, masseter muscle, and occlusal force before and after sagittal split ramus osteotomy in patients with mandibular prognathism.

PURPOSE: The purpose of this study was to examine the relationship between the morphologies of the masseter muscle and the ramus and occlusal force before and after sagittal split ramus osteotomy (SSRO) in patients with mandibular prognathism. PATIENTS AND METHODS: The study group consisted of 26 patients with mandibular prognathism. All patients underwent bilateral SSRO as well as 3-dimensional computed tomography on which the masseter muscle, ramus, and condyle were measured preoperatively and at 1 year postoperation. Occlusal force and contact area were also recorded with pressure-sensitive sheets. RESULTS: In the cross-sectional area of the masseter muscle, there were no significant differences between the pre- and postoperative status. However, postoperative ramus width and area were significantly larger than preoperative values (P < .0001). Postoperative right condylar area was significantly larger than the preoperative value (P = .0120). Occlusal force and contact area 1 year after surgery were significantly larger than the preoperative values (P = .0016, P = .0190). CONCLUSION: This study suggested that the masseter muscle area did not significantly differ from preoperative status 1 year after SSRO, although occlusal force, contact area, and ramus area and width increased significantly 1 year after SSRO.

Determining the anatomy of the descending palatine artery and pterygoid plates with computed tomography in Class III patients.

PURPOSE: Understanding the anatomy of the pterygomaxillary junction region helps prevent blood loss in Le Fort I osteotomy. Here, we determined the location of the descending palatine artery and the structure of the pterygomaxillary region. PATIENTS AND METHODS: The study group consisted of 82 Japanese patients with mandibular prognathism and asymmetry, with and without maxillary retrognathism or asymmetry. A total of 164 sides were measured and divided into right versus left, men versus women, and bimaxillary osteotomy (B) versus mandibular osteotomy (S). Lateral and frontal cephalograms and computed tomography (CT) were analysed for all patients. The relationship between the cephalometric measurements and the measurements of the descending palatine artery and pterygoid plate (PP) were assessed. RESULTS: There were no significant correlations between measurements of cephalograms and those of the descending palatine artery and PPs. There were significant differences between right and left in lateral plate length (p=0.0014) and thickness of PP (p=0.0047). There were significant differences between men and women in right width of PP (p=0.0034), right thickness of PP (p=0.0063), left posterior length (p=0.0196), and left thickness of PP (p=0.0279). The B group had a shorter anterior length than the S group (right: p<0.0001, left: p=0.0027). CONCLUSION: These results suggest that the location of the descending palatine artery and the morphology of the PPs were not significantly associated with any cephalometric measurements. CT examination is necessary to recognize the anatomy of pterygomaxillary region and the exact positions of descending palatine artery before Le Fort I osteotomy.

Loss of maspin is a negative prognostic factor for invasion and metastasis in oral squamous cell carcinoma.

OBJECTIVE: Maspin, a 42-kDa protein, belongs to the serpin family of protease inhibitors and is known to have tumor-suppressor function. In this study, we investigated the interrelationship between clinicopathologic findings and maspin expression in oral squamous cell carcinoma (OSCC). METHODS: Using immunohistochemical techniques to examine the expression levels of maspin in OSCC, maspin expression in OSCC was detected in 46 (64.8%) of 71 cases. We also compared the clonicopathologic features of OSCC cases with maspin expression levels. Moreover, we examined expression of maspin in eight cell lines derived from OSCC using reverse transcriptase-polymerase chain reaction (RT-PCR) and Western blotting. RESULTS: There was a significant correlation between decreased maspin expression and T-category (P < 0.01), lymph metastasis (P < 0.0001), and mode of invasion (P < 0.0001). Patients with positive maspin expression had a significantly better prognosis (P < 0.001). Lower expression of maspin was also seen in cell lines derived from grade 4D, which shows stronger invasive potential than other grades of OSCC. CONCLUSION: Maspin may be a useful marker to identify the potential for progression in OSCC.

Evaluation of bone formation after sagittal split ramus osteotomy with bent plate fixation using computed tomography.

PURPOSE: To evaluate bone formation between the proximal and distal segments after a sagittal split ramus osteotomy (SSRO) with bent plate fixation. PATIENTS AND METHODS: The subjects were 23 patients (46 sides) who underwent bilateral SSRO setback surgery. They were divided into titanium and absorbable plate groups. A 3 to 7-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 square of ramus (RmS), the anteroposterior length (RmA-RmP), and the mediolateral width (RmM-RmL) of the ramus at the horizontal plane under the mandibular foramen were assessed preoperatively, immediately after surgery, and 1 year postoperatively by computed tomography (CT). RESULTS: There were no significant differences between the titanium and absorbable plate groups over time. RmS after 1 year was larger than preoperatively in both groups (P < .0001). RmA-RmP significantly increased immediately after surgery and significantly decreased after 1 year in both groups (P < .0001). RmA-RmP after 1 year was significantly larger than the preoperative value in both groups (P < .0001). RmM-RmL showed a similar tendency to the anteroposterior length, but was not significant. CONCLUSIONS: The gap between the proximal and distal segments can fill with new bone after SSRO with both titanium and absorbable plates, even with few bony contacts between segments.

Significance of stromal desmoplasia and myofibroblast appearance at the invasive front in squamous cell carcinoma of the oral cavity.

BACKGROUND: Tumor invasion involves complex interactions between tumor and stromal cells. We examined the extent of connective tissue in the tumor stroma and whether myofibroblasts play a role in assisting cancer invasion and metastasis. METHODS: Biopsy materials from 84 patients with oral squamous cell carcinoma (SCC) were used. We compared data from intrastromal collagen fibers using Azan staining, immunohistochemical identification of myofibroblasts by cytoskeletal markers, alpha-smooth muscle actin, vimentin, desmin, and clinicopathological parameters. Clinical outcome was compared by 5-year survival rate. RESULTS: There were high levels of stromal collagen fibers in invasive tumors. Myofibroblast appearance increased with increasing tumor invasiveness. Lymph node metastasis occurred more frequently in the myofibroblast-positive group, and the survival rate was significantly poorer in this group. CONCLUSIONS: Fibrous stroma in SCC appeared to have a desmoplastic response. However, an independent invasive mechanism may regulate the stroma, with tumor desmoplasia occurring in highly developed, invasive tumors.

Assessment of pterygomaxillary separation in Le Fort I Osteotomy in class III patients.

PURPOSE: To examine the separation of the pterygomaxillary region at the posterior nasal spine level after Le Fort I osteotomy in Class III patients. PATIENTS AND METHODS: The study group consisted of 37 Japanese patients with mandibular prognathism and asymmetry, with maxillary retrognathism or asymmetry. A total of 74 sides were examined. Le Fort I osteotomy was performed without a pterygoid osteotome, with an ultrasonic curette used to remove interference at the pterygomaxillary region. Postoperative computed tomography (CT) was analyzed for all patients. The separation of the pterygomaxillary region and the location of the descending palatine artery were assessed. RESULTS: Although acceptable separation between the maxilla and pterygoid plates was achieved in all patients, an exact separation of the pterygomaxillary junction at the posterior nasal spine level was found in only 18 of 74 sides (24%). In 29 of 74 sides (39.2%), the separation occurred anterior to the descending palatine artery. In 29 of 74 sides (39.2%), complete separation between the maxilla and lateral and/or medial pterygoid plate was not achieved, but lower level separation of the maxilla and pterygoid plate was always complete. The maxillary segments could be moved to the postoperative ideal position in all cases. CONCLUSION: Le Fort I osteotomy without an osteotome does not always induce an exact separation at the pterygomaxillary junction at the posterior nasal spine level, but the ultrasonic bone curette can remove the interference between maxillary segment and pterygoid plates more safely.

Inhibitory effect of neoadjuvant chemotherapy on metastasis of oral squamous cell carcinoma in a mouse model.

The presence or absence of metastasis bears an important influence on the prognosis of head and neck cancer patients. Neoadjuvant chemotherapy has become widely employed as an initial treatment. However, the actual effectiveness of neoadjuvant chemotherapy on metastasis is still unestablished. Therefore, using an orthotopic implantation model in which cervical lymph node metastasis of oral squamous cell carcinoma can be reproduced, we investigated the inhibitory effect of neoadjuvant chemotherapy on metastasis. A highly invasive and metastatic human oral squamous cell carcinoma cell line, OSC-19 cells, was implanted into the tongues of nude mice. After implantation, the mice were divided into four groups: S (surgery), C+S (preoperative chemotherapy+surgery), S+C (surgery+postoperative chemotherapy), and a control (nontreatment) groups. The treatment (tumor resection or chemotherapy) was started 7 days postimplantation. The effects of each treatment on cervical lymph node metastasis were investigated by examining the rate of lymph node metastasis formation at 28 days postimplantation. In the control group, five of the 11 mice died of cachexia before the end of the experiment. However, all mice in the S, C+S, and S+C groups survived until 28 days after implantation. The cervical lymph node metastasis rates were 81.8% in S, 18.1% in C+S, 63.6% in S+C, and 100% in control groups. Thus, metastasis to the cervical lymph node was markedly inhibited by the combination of neoadjuvant chemotherapy and tumor resection. The findings of this study indicate that neoadjuvant chemotherapy is effective for inhibiting metastasis, and that it is necessary to begin chemotherapy as early as possible to achieve an inhibitory effect on metastasis. Considering these effects, if anticancer drugs are used, better therapeutic results can be expected.

Statin-induced bone morphogenetic protein (BMP) 2 expression during bone regeneration: an immunohistochemical study.

OBJECTIVES: The purpose of this study was to investigate bone morphogenetic protein (BMP) 2 expression after implantation of a statin and recombinant human BMP-2 (rhBMP-2) and to compare the bone regeneration capability of these substances in the rabbit nasal bone using immunohistologic methods. STUDY DESIGN: Twelve adult male Japanese white rabbits (n = 12; age 12-16 weeks, weight 2.5-3.0 kg) were divided into 3 experimental groups and 1 control group. A total of 48 bone defects, 4 per rabbit, were created in the nasal bone while preserving the nasal membrane. In the experimental groups, 1 group was implanted with 10 mg of a statin dissolved in 0.2 mL water with an atelocollagen sponge (ACS); the second group was implanted with 5 microg rhBMP-2 with an ACS; and in the third group only the ACS was implanted. No material was implanted in the control group. Animals were killed at 1, 2, and 4 weeks after surgery. The parts that had been operated on were removed and prepared for histologic assessment. The expression of BMP-2 was evaluated using immunohistochemistry, and double-immunostaining for BMP-2 and Ki-67 was observed by fluorescent microscopy. RESULTS: No significant differences were observed between the statin/ACS group and rhBMP-2/ACS group at 1, 2, and 4 weeks after surgery. The number of cells which stained positively for BMP-2 increased significantly in both of the implanted groups compared with the control group (P < .0001). The positive fluorescent double-immunostaining for BMP-2 and Ki-67 was similar in both implanted groups. CONCLUSION: This study suggests that statin/ACS implants show BMP-2 expression and osteoinductive activity that is similar to those of rhBMP-2/ACS implants.

Changes in the duration of the chewing cycle in patients with skeletal class III with and without asymmetry before and after orthognathic surgery.

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.

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

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.