Aya Mukozawa

Kanazawa University, Kanazawa, Ishikawa, Japan

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Publications (12)19.15 Total impact

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    ABSTRACT: The purpose of this study was to compare the temporal changes in condylar long axis and skeletal stability after sagittal split ramus osteotomy (SSRO) with the hybrid fixation technique and the conventional plate fixation. Of 44 Japanese patients diagnosed with mandibular prognathism, 22 underwent SSRO with the conventional plate fixation (1 u-HA/PLLA plate and 4 monocortical screws in each side) and 22 underwent SSRO with a hybrid fixation technique (1 u-HA/PLLA plate and 4 monocortical screws and bicortical screw in each side). The temporal changes in condylar long axis and skeletal stability were assessed by axial, frontal, and lateral cephalograms. After surgery, breakage of the plate and screws was checked by 3-dimensional computed tomography (3DCT). Although there was a significant difference between the groups regarding Me-Ag in T1 (P = 0.0138), there were no significant differences between the groups for the other measurements in lateral, frontal and axial cephalometric analysis in each time interval. In two cases, 4 sides in the conventional plate fixation group, failure of the absorbable plate was found by 3DCT. However, there was no breakage in the hybrid fixation group. This study suggested that there were no significant differences in the postoperative temporal changes between the two groups in mandibular setback surgery.
    Journal of cranio-maxillo-facial surgery: official publication of the European Association for Cranio-Maxillo-Facial Surgery 07/2013; · 1.25 Impact Factor
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    ABSTRACT: PURPOSE:: The purpose of this study was to compare the bone regenerative capability of using unsintered hydroxyapatite/poly-L-lactic acid (uHA/PLLA) mesh and titanium mesh. MATERIALS AND METHODS:: Adult male white rabbits (n = 24) were divided into 2 groups. After incising along the mandible, 3 × 5 mm bone defects were made in both sides and covered by an uHA/PLLA mesh (n = 12) or a titanium mesh (n = 12) on the right side but no mesh on the left side (n = 12). The rabbits were sacrificed at 1, 2, and 4 weeks postoperatively, 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 BMP-2. RESULTS:: The titanium group and uHA/PLLA group were significantly larger than the control group regarding the bone area ratio postoperatively at 2 and 4 weeks. However, there were no significant differences between the uHA/PLLA group and titanium group regarding the BMP-2. CONCLUSIONS:: 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.
    Implant dentistry 02/2013; · 1.51 Impact Factor
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    ABSTRACT: The purpose of this study was to compare retrospectively postoperative differences in maxillary stability after Le Fort I osteotomy and fixation with an unsintered hydroxyapatite (u-HA)/poly-l-lactic acid (PLLA) plate with or without self-setting α-tricalcium phosphate (Biopex(®)) as interpositional material. Subjects comprised 45 patients diagnosed with mandibular prognathism with maxillary retrognathism and mandibular prognathism with bimaxillary asymmetry. All patients underwent Le Fort I osteotomy and bilateral sagittal split ramus osteotomy with fixation by uHA/PLLA plates. Patients were divided into 4 groups consisting of 9 maxillary impaction cases with Biopex(®) (group 1) to fill the gap between the bone segments, 14 maxillary advancement cases with Biopex(®) (group 2), 8 maxillary impaction cases without Biopex(®) (group 3) and 14 maxillary advancement cases without Biopex(®) (group 4). Changes in cepahalometric parameters at time intervals (1, 3 and 12 months) between the groups were compared. Results showed that stability did not depend on the use or otherwise of Biopex(®).
    International Journal of Oral and Maxillofacial Surgery 11/2012; · 1.52 Impact Factor
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    ABSTRACT: PURPOSE: The purpose of this study was to evaluate hypoesthesia of the upper lip and bone formation using self-setting α-tricalcium phosphate (Biopex(®)) between the segments following Le Fort I osteotomy with bent absorbable plate fixation. SUBJECTS AND METHODS: The subjects were 47 patients (94 sides) who underwent Le Fort I osteotomy with and without mandibular osteotomy. They were divided into a Biopex(®) group (48 sides) and a control group (46 sides). The Biopex(®) was inserted into the anterior part of the gap between the segments in the Biopex(®) group. Trigeminal nerve hypoesthesia at the region of the upper lip was assessed bilaterally by the trigeminal somatosensory-evoked potential (TSEP) method. The area of the Biopex(®) at the anterior part in the maxilla was assessed immediately after surgery and 1 year postoperatively by computed tomography (CT). RESULTS: The mean measurable period and standard deviation were 13.2 ± 18.5 weeks in the control group, 14.5 ± 17.9 weeks in the Biopex(®) group, and there was no significant difference in TSEP. The area of the Biopex(®) after 1 year was significantly smaller than that immediately after surgery (right side: P = 0.0024, left side: P = 0.0001) and bone defects between the segments could not be found in the Biopex(®) group. In the control group, although the areas of bone defect after 1 year were significantly smaller than that immediately after surgery on the right side (P = 0.0133) and left side (P = 0.0469) in the frontal view, complete healing of the bone defects could be seen in 12 of 46 sides after 1 year. CONCLUSION: This study suggested that inserting Biopex(®) in the gap between the maxillary segments was useful for new bone formation and it did not prevent the recovery of upper lip hypoesthesia after Le Fort I osteotomy with absorbable plate fixation.
    Journal of cranio-maxillo-facial surgery: official publication of the European Association for Cranio-Maxillo-Facial Surgery 07/2012; · 1.25 Impact Factor
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    ABSTRACT: 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.
    International Journal of Oral and Maxillofacial Surgery 03/2012; 41(7):835-8. · 1.52 Impact Factor
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    ABSTRACT: 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. 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). 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). 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.
    Journal of cranio-maxillo-facial surgery: official publication of the European Association for Cranio-Maxillo-Facial Surgery 08/2011; 40(4):e119-24. · 1.25 Impact Factor
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    ABSTRACT: To evaluate bone healing following implantation of a statin with two different carriers in rabbit nasal bone using histological and immunohistochemical methods. Twenty adult, male Japanese white rabbits (age: 12-16 weeks, weight: 2.5-3 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. 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. 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). 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.
    Clinical Oral Implants Research 07/2011; 22(11):1327-35. · 3.43 Impact Factor
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    ABSTRACT: The purpose of this study was to examine bone healing after Le Fort I osteotomy in Class III patients. 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. 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. 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.
    Journal of cranio-maxillo-facial surgery: official publication of the European Association for Cranio-Maxillo-Facial Surgery 06/2011; 39(4):237-43. · 1.25 Impact Factor
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    ABSTRACT: 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. 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. 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. 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.
    Journal of oral and maxillofacial surgery: official journal of the American Association of Oral and Maxillofacial Surgeons 01/2011; 69(5):1464-8. · 1.58 Impact Factor
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    ABSTRACT: 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. 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. 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-2-stained cells in the experimental side was significantly larger than in the control side after 4 and 12 weeks (P < .05). 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.
    Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology, and Endodontology 11/2010; 110(5):560-9. · 1.50 Impact Factor
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    ABSTRACT: The purpose of this study was to evaluate changes in the mandibular canal and ramus morphology before and after a sagittal split ramus osteotomy. 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. 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. 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.
    Journal of oral and maxillofacial surgery: official journal of the American Association of Oral and Maxillofacial Surgeons 08/2010; 68(8):1795-801. · 1.58 Impact Factor
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    ABSTRACT: 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. 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. 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). 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.
    Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology, and Endodontology 08/2009; 108(5):679-86. · 1.50 Impact Factor