Shamiul Alam

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.

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.

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.

The effects of changing position and angle of the proximal segment after intraoral vertical ramus osteotomy

The authors evaluated changes in position and angle of the proximal segment, including the condyle, after intraoral vertical ramus osteotomy (IVRO) with and without a Le Fort I osteotomy to verify whether displacement of the proximal segment could induce postoperative complications. Changes in condylar angle, ramus angle, and displacement of proximal segment were measured pre- and postoperatively. The position of the temporomandibular joint (TMJ) disc was examined pre- and postoperatively. Trigeminal nerve hypoesthesia in the lower lip was assessed bilaterally. The postoperative horizontal condylar angle was significantly smaller than the preoperative one on the deviated and non-deviated sides (P<0.0001). The postoperative coronal condylar angle was significantly larger than the preoperative one on the deviated side (P=0.0483). The postoperative sagittal ramus angle was larger than the preoperative one on the deviated (P<0.0001) and non-deviated (P=0.00005) side. Most joints with an anteriorly-displaced disc with and without reduction improved on the non-deviated side; 5 of 16 joints improved on the deviated side. Results suggest the position and angle of the proximal segment, including the condyle, could change after IVRO. This could be associated with symptomatic improvement in TMJ, and extreme medial displacement of the proximal segment could delay recovery from lower lip hypoesthesia.

Skeletal Stability After Mandibular Setback Surgery: Bicortical Fixation Using a 2.0-mm Locking Plate System Versus Monocortical Fixation Using a Nonlocking Plate System

PURPOSE This study was conducted to compare the time-course changes in condylar long-axis and skeletal stability after sagittal split ramus osteotomy (SSRO) with bicortical plate fixation versus monocortical plate fixation. PATIENTS AND METHODS Of a group of 40 Japanese patients diagnosed with mandibular prognathism, 20 underwent SSRO with bicortical plate fixation using a locking plate system and the other 20 underwent SSRO with monocortical plate fixation using a conventional plate system. The time-course changes in condylar long-axis and skeletal stability were assessed through axial, frontal, and lateral cephalograms. RESULTS Significant differences were found between the 2 groups in changes of the left condylar angle between the initial and 1-month measurements (P = .0454) and in ANB between the 1- and 3-month measurements (P = .0206); however, no significant differences were found between the 2 groups in the other measurements in each time interval. CONCLUSIONS Our findings suggest no significant differences in postoperative time-course changes between bicortical plate fixation using a locking plate system and monocortical plate fixation using a conventional plate system.

The evaluation of surgical factors related to recovery period of upper lip hypoaesthesia after Le Fort I osteotomy

PURPOSE It is unclear whether surgical factors can affect the upper lip sensitivity. The aim of this study was to assess the factors that can affect the recovery period of hypoaesthesia of the upper lip after Le Fort I osteotomy, using trigeminal somatosensory evoked potential (TSEP) objectively. PATIENTS AND METHODS Twenty-nine patients with mandibular prognathism underwent Le Fort I osteotomy with and without artificial pterygoid plate fracture. Trigeminal nerve hypoaesthesia at the region of the upper lip was assessed bilaterally by the TSEP method. The distance between the infraorbital foramen and the osteotomy line (IO) or the nearest plate/screw position (IP) was measured on three-dimensional computed tomography (CT). The relationship between the recovery period in upper lip hypoaesthesia and surgical factors (these distances, movement amount, pterygoid plate fracture) were analysed statistically. RESULTS The recovery period in upper lip hypoaesthesia did not significantly correlate with IO, IP and movement amount. There was no significant difference between pterygoid plate fracture group and non-fracture group. CONCLUSION Temporary hypoaesthesia of upper lip after Le Fort I osteotomy could not be avoided, however, osteotomy line, plate/screw position and pterygoid plate fracture in Le Fort I osteotomy did not affect the recovery period of upper lip hypoaesthesia with TSEP.