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

金沢大学医薬保健研究域医学系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, 2.5-3kg) 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. © 2010 John Wiley & Sons A/S

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

金沢大学医薬保健研究域医学系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. © 2009 European Association for Cranio-Maxillofacial Surgery

An experimental study of use of absorbable plate in combination with self-setting α-tricalcium phosphate for orthognathic surgery

金沢大学医薬保健研究域医学系Objective: The purpose of this study was to histologically and immunohistochemically evaluate bone formation using both self-setting α-tricalcium phosphate (α-TCP; Biopex) and absorbable plate (Super Fixsorb-MX) in rabbit cranium bone. Study design: Twelve adult male Japanese white rabbits (12-16 wk, 2.5-3.0 kg) were used. The surgical defects were made in the nasal bone of a rabbit, and Biopex was implanted in the left side and no material in the right side. Two-hole absorbable plate and 2 screws (Super Fixsorb-MX) were fixed across the defect in each side. The rabbits were killed at 1, 4, 12, and 24 weeks after surgery, and formalin-fixed specimens were embedded in acrylic resin. The specimens were stained with hematoxylin and eosin. For immunohistochemical analysis, the specimens were treated with bone morphogenetic protein 2 (BMP-2) antibodies. Finally, these were evaluated microscopically. Results: New bone formation was observed in the region of absorbable plate and nasal membrane after >4 weeks. The area of new bone with Biopex was significantly larger than that of the control side after 1, 4, and 12 weeks (P < .05). The number of BMP-2stained cells in the experimental side was significantly larger than in the control side after 4 and 12 weeks (P < .05). Conclusion: This study suggests that the use of absorbable plate (Super Fixsorb-MX) in combination with Biopex could be useful and that both of Super Fixsorb-MX and Biopex could provide adequate bone regeneration. © 2010 Mosby, Inc

Bone healing of critical-sized nasal defects in rabbits by statins in two different carriers

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: 2.5-3kg) were used in this study. Five bone circular defects (5mm in diameter) per rabbit were created in the nasal bone while preserving the nasal membrane. In the experimental groups, 2.5mg/ml simvastatin dissolved in 0.2ml water with hydrogel was implanted in one group, 2.5mg/ml simvastatin dissolved in 0.2ml 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. Four 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 bone morphogenetic proteins (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 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. To cite this article: , Mukozawa A, Ueki K, Marukawa K, Okabe K, Moroi A, Nakagawa K. Bone healing of critical-sized nasal defects in rabbits by statins in two different carriers., Clin. Oral Impl. Res. xx, 2011; 000-000., doi: 10.1111/j.1600-0501.2010.02135.x © 2011 John Wiley & Sons A/S

Assessment of Pterygomaxillary Separation in Le Fort I Osteotomy in Class III Patients

金沢大学医薬保健研究域医学系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. © 2009 American Association of Oral and Maxillofacial Surgeons

Esthetic improvement using conventional orthodontic devices after segmental osteotomy in treatment of malpositioned implants

金沢大学医薬保健研究域医学

Evaluation of Bone Formation After Sagittal Split Ramus Osteotomy With Bent Plate Fixation Using Computed Tomography

金沢大学医薬保健研究域医学系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. © 2009 American Association of Oral and Maxillofacial Surgeons

Maxillary stability after le Fort i osteotomy using three different plate systems

The purpose of this study was to compare postoperative changes in maxillary stability after Le Fort I osteotomy in three groups: with an unsintered hydroxyapatite (u-HA)/poly-l-lactic acid (PLLA) plate; a PLLA plate; and a titanium plate. Subjects comprised 60 Japanese patients diagnosed with mandibular prognathism. All patients underwent Le Fort I osteotomy and bilateral sagittal split ramus osteotomy. All patients were randomized in groups of 20 to a u-HA/PLLA group, a PLLA plate group and a titanium plate group. Changes in postoperative time intervals between the plate groups were compared using lateral and posteroanterior cephalography. The uHA/PLLA group had significantly larger values than the PLLA group regarding change of mx1-S perpendicular to SN between 3 and 12 months (T3) (P = 0.0269). The uHA/PLLA group had a significantly larger value than the PLLA group regarding change of S-A perpendicular to SN between baseline and 1 month (T1) (P = 0.0257). There was no significant difference in the other measurements. This study suggests that maxillary stability with satisfactory results could be obtained in the u-HA/PLLA, PLLA plate and titanium plate groups, although there was a slight difference between the u-HA/PLLA and PLLA plate systems in Le Fort I osteotomy. © 2012 International Association of Oral and Maxillofacial Surgeons

Changes in the lip closing force of patients with Class III malocclusion before and after orthognathic surgery

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. Control groups consisted of 20 women and 20 men with normal occlusion without dento-alveolar deformity. Maximum and minimum lip closing force was measured with Lip De Cum ® for the control groups and subject groups preoperatively and 6 months postoperatively. The difference between the pre- and postoperative values of the groups was examined statistically. 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 the control group (p = 0.0097). The preoperative Class III group was significantly smaller than the control group in maximum lip closing force in both men (p < 0.0001) and women (p < 0.0001). The 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. © 2012 International Association of Oral and Maxillofacial Surgeons