Differences in bone remodeling using demineralized bone matrix in bilateral sagittal split ramus osteotomy: a study on volumetric analysis using three-dimensional cone-beam computed tomography.

PURPOSE: The aim of this study was to examine the effects of demineralized bone matrix (DBM) grafts on bone remodeling during sagittal split ramus osteotomy by measuring 3-dimensional (3D) reconstructed images. PATIENTS AND METHODS: Forty-eight patients were selected for this study. In the control group, no grafts were performed. In the DBM group, DBX grafts were placed between the proximal and distal segments. Three-dimensional cone-beam computerized tomographic (3D-CBCT) images were obtained within 1 week, after 3 months (T2), and after 6 months (T3) postoperatively. By measuring the total skeletal volume from the right condylar head to the right mandibular first molar, the volume of the graft site was measured indirectly. Using the data thus obtained, a volume-increasing ratio (percentage) was computed. SimPlant analytical software was used to analyze the 3D reconstructed volumes. RESULTS: The 2 groups showed a significant increase in volume. However, in the same period, the volume-increasing ratios of the 2 groups showed significant differences. In the control group, a significant increase in volume was seen until T2, after which a negligible increase was seen. Conversely, in the DBM group, a significant volume increase continued until T3. CONCLUSION: In orthognathic surgeries, grafting using DBM is a favorable procedure that accelerates bone formation. Therefore, in cases with inevitable large bony gaps, DBM grafts can play a positive role in the stable healing of segments and the prevention of postoperative complications. Moreover, because volumetric analysis using 3D-CBCT analyzing software is a fast and simple method, future studies using this technique are expected to increase.

Usefulness of the retromandibular transparotid approach for condylar neck and condylar base fractures.

Condyle fractures represent 20% to 30% of all mandibular fractures and are thus among the most common facial fractures. The fracture pattern can vary greatly and may occur anywhere along the line from the sigmoid notch to the mandibular angle. The main problems are access, difficulty in repositioning the extremely slender fragments, and fixation of the condyle.Eighty-seven patients were diagnosed with condylar neck or condylar base fractures from January 2007 to December 2009 in the Department of Oral & Maxillofacial Surgery of Kyung Hee University Dental Hospital. In this study, we included 35 patients who underwent open surgery and a total of 28 patients who were treated using a retromandibular transparotid approach.Surgical treatment aims were anatomic repositioning and rigid fixation of the fragments, occlusal stability, rapidly return to function, maintenance of vertical ramus dimension, no airway compromise, and reduced long-term temporomandibular joint dysfunction. Considering the high rate of occurrence of condylar fracture and the importance of the condylar as a growth center of the mandible, extraoral approaches for the open reduction of condylar fractures are considered effective and can be used widely.Short access route, easy reduction, short operating time, and stable postoperative occlusion are the advantages of the retromandibular transparotid approach. Also, there was no permanent damage from facial nerve injury, salivary leakage, or preauricular hypoesthesia. Therefore, the retromandibular transparotid approach is considered a safe and effective method for patients with a condylar neck or condylar base fracture classified according to the Strasbourg Osteosynthesis Research Group's classification, who require surgical treatment with an extraoral approach.