Maxillary bone healing and CT value after Le Fort I osteotomy using absorbable plate system: A retrospective study.

This study aimed to evaluate maxillary bone healing and computed tomography (CT) values after Le Fort I osteotomy with sagittal split ramus osteotomy in patients with class II and III malocclusion. Four absorbable plates and screws were used to fix the maxillary segments in all patients. For 112 sides (58 patients), the bone defect areas at the anterior and posterior sites between the maxillary segments were measured using 3-dimensional CT views reconstructed over a constant CT value at 1 week and 1 year postoperatively. Subsequently, CT values at the upper, middle, and lower sites around the osteotomy line in the medial, middle, and lateral regions were measured. The bone defect area after 1 year increased at the anterior site in class III and at both the anterior and posterior sites in class II (P < 0.05). This study suggests that the increase in bone defect area was affected by lower CT values at the middle site of the middle and lateral regions in class II, and that bony defects between fragments in the maxilla could partially remain in both classes II and III within 1 year after Le Fort I osteotomy.

Bone healing and stability after advancement genioplasty using a pre-bent absorbable plate and screws.

This study aimed to compare the bone healing and stability of the chin with a pre-bent absorbable plate and a manually bent absorbable plate after advancement genioplasty. Patients with class II malocclusion who underwent genioplasty with bimaxillary surgery were included. After genioplasty, two absorbable bicortical screws were fixed on both sides. Then, a pre-bent absorbable plate and screws were used in the center area to fix the segment in advancement genioplasty (PB group). A manually bent absorbable plate was used for the remaining patients (MB group). Computed tomography (CT) was performed before surgery and 1 week and 1 year after surgery. Changes in the pogonion (Pog) and menton (Me) points, soft tissue points, and the ratio of bone squares under the plate were evaluated using lateral cephalometric images reconstructed with 3-dimensional CT data. 32 patients were included in the study. There were no significant differences in the cephalometric measurements in the time interval from 1 week to 1 year. However, the bone square ratio in the PB group showed a significant increase after 1 year (P = 0.0021). Within the limitations of the study it seems that the use of a pre-bent absorbable plate is effective in promoting bone healing after advancement genioplasty.

Change in CT Value at Mandibular Ramus After Mandibular Setback and Advancement Surgery With Bicortical Absorbable Plate Fixation.

PURPOSE: This study aimed to evaluate changes in computed tomography (CT) value of ramus bone after sagittal split ramus osteotomy (SSRO) in class II and class III patients using absorbable plates and screws. PATIENTS AND METHODS: In the retrospective study, the participants were female patients with jaw deformities who underwent bilateral SSRO with Le Fort I osteotomy. Maximum CT values (pixel values) of lateral and medial cortexes at anterior and posterior sites of the ramus were measured preoperatively and 1 year postoperatively by using horizontal planes at the mandibular foramen level (upper level) and 10 mm under the mandibular foramen level (lower level) parallel to Frankfurt horizontal plane. RESULTS: Fifty-seven patients and 114 sides (28 class II: 56 sides and 29 class III: 58 sides) were evaluated. Although CT values decreased at most sites of the ramus cortical bone after 1 year of surgery, they increased at the posterior-medial site at the upper level in class II ( P =0.0012) and the lower level in class III ( P =0.0346). CONCLUSION: This study suggested that bone quality at the mandibular ramus could change after 1 year of surgery, and there could be differences between mandibular advancement and setback surgery.