No abstract available.
Mandibular Osteotomy*

BACKGROUND: Mandibular reconstruction is performed after segmental mandibulectomy, and precise repositioning of the condylar head in the temporomandibular fossa is essential for maintaining preoperative occlusion. METHODS: In cases without involvement of soft tissue around the mandibular bone, the autopolymer resin in a soft state is pressed against the lower border of the mandible and buccal and lingual sides of the 3D model on the excised side. After hardening, it is shaved with a carbide bar to make the proximal and distal parts parallel to the resected surface in order to determine the direction of mandibular resection. On the other hand, in cases that require resection of soft tissue around the mandible such as cases of a malignant tumor, right and left mandibular rami of the 3D model are connected with the autopolymer resin to keep the preoperative position between proximal and distal segments before surgical simulation. The device is made to fit the lower border of the anterior mandible and the posterior border of the mandibular ramus. The device has a U-shaped handle so that adaptation of the device will not interfere with the soft tissue to be removed and has holes to be fixed on the mandible with screws. RESULTS: We successfully performed the planned accurate segmental mandibulectomy and the precise repositioning of the condylar head by the device. CONCLUSIONS: The present technique and device that we developed proved to be simple and useful for restoring the preoperative condylar head positioning in the temporomandibular fossa and the precise resection of the mandible.
Hand ; Head ; Mandible* ; Mandibular Osteotomy* ; Mandibular Reconstruction

OBJECTIVES: To evaluate the influence of the type of osteotomy in the inferior aspect of the mandible on the mechanical performance. MATERIALS AND METHODS: The study was performed on 20 polyurethane hemimandibles. A sagittal split ramus osteotomy (SSRO) was designed in 10 hemimandibles (group 1) with a vertical osteotomy in the buccal side (second molar level) and final osteotomy was performed horizontally on the lingual aspect, while the mandible body osteotomy was finalized as a straight osteotomy in the basilar area, perpendicular to the body. For group 2, the same osteotomy technique was used, but an oblique osteotomy was done in the basilar aspect of the mandibular body, forming continuity with the sagittal cut in the basilar area. Using a surgical guide, osteosynthesis was performed with bicortical screws using an inverted L scheme. In both groups vertical compression tests were performed with a linear load of 1 mm/min on the central fossa of the first molar and tests were done with models made from photoelastic resin. Data were analyzed using Student's t-test, establishing a statistical significance when P <0.05. RESULTS: A statistical difference was not observed in the maximum displacements obtained in the two osteotomies (P <0.05). In the extensiometric analysis, statistically significant differences were identified only in the middle screw of the fixation. The photoelastic resin models showed force dissipation towards the inferior aspect of the mandible in both SSRO models. CONCLUSION: We found that osteotomy of the inferior aspect did not influence the mechanical performance for osteosynthesis with an inverted L system.
Mandible ; Mandibular Osteotomy ; Molar ; Osteotomy ; Osteotomy, Sagittal Split Ramus* ; Polyurethanes

Mandibular widening is one method of mandibular distraction osteogenesis, which has anatomic limitations such as curved surface, mandibular condyle and narrow arch. The purpose of this study was to understand the biomechanics of various mandibular widening procedures. Experimental models consisted of 6 groups according to different osteotomy lines and distractor positions. The results of this study showed different expansion patterns, which meant the need for proper approaches in mandibular widening.
Mandibular Condyle ; Models, Theoretical ; Osteogenesis, Distraction ; Osteotomy

mandibular osteotomies. Our method includes a condylectomy to arrest the continued condylar growth or to excise the neoplastic condyle, unilateral vertical ramus osteotomy to allow horizontal rotation of the mandible without significantly altering the temporomandibular articulations, and an arthroplasty by superior repositioning of the stump of the proximal condylar segment into the condylar fossa. Both the facial asymmetry and the occlusion were corrected by rotation of the mandible around the unaffected condyle.]]>
Arthroplasty ; Facial Asymmetry ; Humans ; Hyperplasia ; Mandible ; Mandibular Osteotomy ; Osteotomy

mandibular retrognathism is represented by two methods, distraction osteogenesis (DO) and mandibular osteotomy surgery. The DO is mostly preferred when the degree of advancement of mandible is large. However, the postoperative stability of mandibular advancement using DO have not been actively investigated. Therefore, in the present study we have compared the postoperative stability between DO and bilateral sagittal split ramus osteotomy (BSSRO) in mandibular retrognathism.METHODS: Seven patients who had been treated by DO and thirteen patients with BSSRO were included in this study. Serial lateral cephalograms were analyzed by manual tracing and the amount of the mandibular elongation was measured. To evaluate the postoperative stability, positional changes of the condylar position and B point were analyzed.RESULTS: Mean amount of mandibular advancement was 6.51+/-3.57 mm for BSSRO group and 12.43+/-4.35 mm for DO group, respectively. There was no significant difference in age between the two groups (P>0.05). Mean follow up periods were 10.77 months for BSSRO group and 11.28 months for DO group, respectively. After mandibular advancement, mean positional changes in the condyle were 0.56+/-1.43 mm horizontally and 0.72+/-1.61 mm vertically for BSSRO group and 0.53+/-1.56 mm horizontally and 0.56+/-1.75 mm vertically for DO group, respectively. Mean change of distance from B point to Y-axis was -1.76+/-0.83 mm for BSSRO group and -2.14+/-1.82 mm for DO group, respectively. According to the condylar position and B point, there were no significant differences in postoperative stability between the two groups (P>0.05).CONCLUSION: There was no significant difference in postoperative stability between DO and BSSRO group according to condylar position and B point. Based on the results of the present study, it is hypothesized that DO would be a good treatment choice for severe mandibular retrognathism because DO could achieve more mandibular advancement and concurrent soft tissue elongation.]]>
Follow-Up Studies ; Humans ; Mandible ; Mandibular Advancement ; Mandibular Osteotomy ; Osteogenesis, Distraction ; Osteotomy, Sagittal Split Ramus ; Retrognathia

OBJECTIVES: Buccal fracture of the mandibular proximal bone segment during bilateral sagittal split ramus osteotomy (SSRO) reduces the postoperative stability. The primary aim of this study is to evaluate the effect of this type of fracture on bone healing and postoperative stability after mandibular setback surgery. MATERIALS AND METHODS: Ten patients who experienced buccal fracture during SSRO for mandibular setback movement were evaluated. We measured the amount of bone generation on a computed tomography scan, using an image analysis program, and compared the buccal fracture side to the opposite side in each patient. To investigate the effect on postoperative stability, we measured the postoperative relapse in lateral cephalograms, immediately following and six months after the surgery. The control group consisted of ten randomly-selected patients having a similar amount of set-back without buccal fracture. RESULTS: Less bone generation was observed on the buccal fracture side compared with the opposite side (P<0.05). However, there was no significant difference in anterior-posterior postoperative relapse between the group with buccal fracture and the control group. The increased mandibular plane angle and anterior facial height after the surgery in the group with buccal fracture manifested as a postoperative clockwise rotation of the mandible. CONCLUSION: Bone generation was delayed compared to the opposite side. However, postoperative stability in the anterior-posterior direction could be maintained with rigid fixation.
Fracture Healing ; Humans ; Mandibular Fractures ; Osteotomy, Sagittal Split Ramus* ; Recurrence

The purpose of this study was to evaluate the resistant force of medial pterygoid muscles against the mandibular advancement and distraction to anterior, and inquire into the relationship between medial pterygoid muscles and cephalometric variables. Sixty six patients with class III malocclusion underwent bilateral sagittal splitting of ramus with intraoralvertico-sagittal ramus osteotomy for mandibular set-back. The spring scale was used to measure the resistance of medial pterygoid muscles after splitting of ramus. Skeletaldental cephalometric analysis was made and statistic package was used for correlation between resistance and cephalometric variables. The resistant force of the right medial pterygoid muscle was greater than the left one in Koreans with class III malocclusion, and the force had a linear regression relationship with facial depth. The results suggested that facial depth has significant correlation with the resistance of medial pterygoid muscle, which can be acquired from patient's cephalometric analysis.
Humans ; Linear Models ; Malocclusion ; Mandibular Advancement ; Osteotomy ; Pterygoid Muscles*

Two patients, sought treatment for chief complaints of protruding frontal tooth and desired treatment to reduce the prominence of lips, were diagnosed as bimaxillary protrusion via clinical and cephalometric analysis. The authors corrected them by combined surgical and orthodontic treatment. As pre-surgical survey, paper and cast surgery were performed and wafer and resin sprint were constructed. We performed anterior maxillary and mandibular osteotomies in first premolar site to retract the maxillary and mandibular dentoalveolar segment in order to; 1) Decrease prominence of upper and lower lips. 2) Create proper lower incisor intrusion. By use of intramaxillary fixation, prompt oral intake was possible. We made good result of esthetic improvement and there was no evidence of relapse and any complication.
Adult* ; Bicuspid ; Humans ; Incisor ; Lip ; Mandibular Osteotomy ; Recurrence ; Tooth

BACKGROUND: Osteochondroma is a benign tumor that tends to develop in mandibular condyle and coronoid process in the craniofacial region. If tumor mass has grown from condyle into the infratemporal space with zygomatic arch obstructing the access, there are risks associated with surgical exposure and local resection of these masses. CASE PRESENTATION: This study reports on a case of osteochondroma on mandibular condylar head where we treated with surgical excision via preauricular approach with 3D analysis. After the local resection, there were no surgical and post-operative complications until 8-month follow-up period. CONCLUSIONS: In local excision of osteochondroma, our method is a minimally invasive method. It is a good example of osteochondroma treatment.
Follow-Up Studies ; Head ; Mandibular Condyle* ; Methods ; Osteochondroma* ; Osteotomy* ; Zygoma*