Objectives: To evaluate bone healing following implantation of a statin with two different carriers in rabbit nasal bone using histological and immunohistochemical methods. Materials and methods:Twenty adult male Japanese white rabbits (age: 12-16 weeks, weight: 2.5-3.0 kg) were used in this study. Five bone circular defects (5 mm in diameter) per rabbit were created in the nasal bone while preserving the nasal membrane. In the experimental groups, 2.5 mg/ml simvastatin dissolved in 0.2 ml water with hydrogel was implanted in one group, 2.5 mg/ml simvastatin dissolved in 0.2 ml water with an atelocollagen sponge (ACS) in the second group with, only the hydrogel in the third group and only an ACS in the fourth group. No material was implanted in the control group. 4 animals were killed in each period, at 1-, 2-, 4-, 8-and 12 weeks postoperatively. The parts that had been operated on were removed and prepared for histological assessment. The expression of BMP-2 and the bone ration was evaluated using histological and immunohistochemical methods.Results: No significant differences were observed between the simvastatin with hydrogel group and the simvastatin with ACS group at 1, 2, 4, 8 and 12 weeks postoperatively regarding expression of BMP-2, although the number of cells that 3 stained positive for BMP-2 in both of the implanted groups increased significantly at 2 and 4 weeks postoperatively in comparison with the control group (P<0.0001). For new bone area ratio, there were no significant differences between the simvastatin with hydrogel groups and the simvastatin with ACS group after 2, 4, 8 and 12 weeks, although these groups showed higher value than control group (P<0.0001). Conclusion:This study suggests that both the simvastatin with hydrogel and simvastatin with ACS implants showed similar BMP-2 expression and new bone formation, and there were no significant differences between the two carriers. R R 4

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Key words:Bone healing, Pterygoid plate, Le Fort I osteotomy, ultrasonic bone curette, 3-demensional computed tomography (3DCT) AbstractPurpose. 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 ten patients, in the same manner.Postoperative computed tomography (CT) was analyzed for all patients pre-operatively and 1 year post-operative. 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 pterygo-maxillary junction was found in all cases without artificial pterygoid plate fracture.14 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.

The purpose of this study was to examine the changes in lip pressure before and after orthognathic surgery for skeletal Class III patients.The subject groups were 32 female and 31 male patients diagnosed with mandibular prognathism and/or maxillary retrognathism who underwent orthognathic surgery. The maximum lip closing force in men was significantly larger than that in women in both the preoperative Class III group (p=0.0330) and control group (p=0.0097).Preoperative Class III group was significantly smaller than the control group in the maximum lip closing force in both men (p<0.0001) and women (p<0.0001).Postoperative maximum lip closing force was significantly larger than the preoperative value in both men (p=0.0037) and women (p=0.0273) in the Class III group. This study suggested that the maximum lip closing force increases after orthognathic surgery in Class III patients.3

This study suggested that the uHA/PLLA mesh could increase new bone formation more than the absence of a mesh in bone defects. However, there was no significant difference between uHA/PLLA mesh and the titanium mesh in bone augmentation.