• 대한치과교정학회지
• /
• 제50권5호
• /
• pp.324-335
• /
• 2020

Objective: To compare postoperative positional changes in the mandibular proximal segment between the conventional orthognathic surgery (CS) and the surgery-first approach (SF) using intraoral vertical ramus osteotomy (IVRO) in patients with Class III malocclusion. Methods: Thirty-eight patients with skeletal Class III malocclusion who underwent bimaxillary surgery were divided into two groups according to the use of preoperative orthodontic treatment: CS group (n = 18) and SF group (n = 20). Skeletal changes in both groups were measured using computed tomography before (T0), 2 days after (T1), and 1 year after (T2) the surgery. Three-dimensional (3D) angular changes in the mandibular proximal segment, condylar position, and maxillomandibular landmarks were assessed. Results: The mean amounts of mandibular setback and maxillary posterior impaction were similar in both groups. At T2, the posterior portion of the mandible moved upward in both groups. In the SF group, the anterior portion of the mandible moved upward by a mean distance of 0.9 ± 1.0 mm, which was statistically significant (p < 0.001). There were significant between-group differences in occlusal changes (p < 0.001) as well as in overjet and overbite. However, there were no significant between-group differences in proximal segment variables. Conclusions: Despite postoperative occlusal changes, positional changes in the mandibular proximal segment and the position of the condyles were similar between CS and SF, which suggested that SF using IVRO achieved satisfactory postoperative stability. If active physiotherapy is conducted, the proximal segment can be adapted in the physiological position regardless of the occlusal changes.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• 제47권4호
• /
• pp.249-256
• /
• 2021

Objectives: The purpose of this study was to evaluate the postoperative anteroposterior stability and improvements in facial asymmetry after performing LeFort I osteotomy in the maxilla, sagittal split ramus osteotomy (SSRO) and intraoral vertical ramus osteotomy (IVRO) in the mandible, and lateral corticectomy on the IVRO side. Materials and Methods: From July 2009 to October 2018, a retrospective analysis was performed on 11 subjects. Lateral cephalometric radiograph was performed preoperatively (T0), postoperatively (T1), and at 12 months of follow-up (T2), and the B point distance was measured. Posteroanterior cephalometric radiograph was performed preoperatively (S0) and at 12 months of follow-up (S1) and was used to measure five indicators (Ag angle, M-Ag, Co-Ag, Co-Me, and Ag-Me) of facial asymmetry. Results: The B point distances for T0 and T1 were significantly different (P=0.007), whereas those for T1 and T2 were not significantly different (P=0.1). In addition, there was a significant difference between the B point distances of T2 and T0 (P=0.026). Comparison of the facial asymmetry indicators before and after surgery showed a significant difference for all indicators between S0 and S1: the P-values of Ag angle, M-Ag, Co-Ag, Co-Me, and Ag-Me were 0.003, 0.003, 0.008, 0.006, and 0.004, respectively. The Z value was based on negative ranks. Conclusion: There was no significant difference in the B point distances from postoperation to the 12-month follow-up. However, there were significant differences in all five indicators related to facial asymmetry before and after surgery. The values for the five indicators of facial asymmetry all increased postoperatively.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• 제33권5호
• /
• pp.559-566
• /
• 2007

Distraction osteogenesis(DO) is a surgical method of bone formation that involves an osteotomy and sequential stretching of the healing callus by gradual movement and subsequent remodeling. DO is used to correct facial asymmetry, such as in patients with hemifacial microsomia, maxillary or mandibular retrusion, cleft lip and palate, alveolar defects, and craniofacial deficiency. It is accomplished with the aid of a distraction device, which is secured with screws placed directly into bone, for a predetermined length of time. Hemifacial microsomia is characterized by unilateral facial hypoplasia, often with unilateral shortening of the mandible and subsequent malocclusion. Patients with hemifacial microsomia and facial asymmetry have a vertically short maxilla, tilted occlusal plane, and short mandible. Early treatment is necessary to avoid subsequent impaired midfacial growth. The standard treatment of these malformations consists of the application of bone grafts, which can lead to unpredictable growth. The new bone-lengthening procedure represents a limited surgical intervention and opens up a new perspective for treatment, especially in younger children with severe deformities. This report describes a case of hemifacial microsomia(Type-II left-sided hemifacial microsomia). The patient, a 10-year-old child, visited our clinic for facial asymmetry correction. He had a hypoplastic mandible, displaced ear lobe, 10 mm canting on the right side, and malocclusion. We planned DO to lengthen the left mandible in conjunction with a Le Fort I osteotomy for decanting and then perform a right intraoral vertical ramus osteotomy(IVRO). Progressive distraction at a rate of 0.5 mm/12 hours was initiated 7 days postoperatively. The duration of DO was 17 days. The consolidation period was 3 months. Satisfactory results were obtained in our case, indicating that DO can be used successfully for functional, aesthetic reconstruction of the mandible. We report a case involving DO in conjunction with orthognathic surgery for correcting mandibular hypoplasia with a review of the literature.

• 대한치과교정학회지
• /
• 제27권2호
• /
• pp.283-296
• /
• 1997

악구강계는 측두하악관절, 근육신경계, 치아, 그리고 지지조직의 복합적구성체로 되어있어 다양한 구조를 이루고 있으며, 밀접한 생리적 관계를 유지하고 있다. 특히 하악은 저작근을 포함한 여러 근육을 운동원으로 하여 각종 기능을 수행하고 있으며, 이들 근기능의 활성도는 치근막을 비롯한 악관절과 근육 등의 여러 가지 형태의 수용기를 거쳐 말초신경계와 중추신경계의 복잡한 경로와 기전에 의해서 조절되어지는데, 교정치료, 특히 교정을 동반한 악교정 수술시에는 이러한 악구강계의 변화와 구강내 여러감각 수용기의 변화, 근활성도의 변화가 심하게 나타나며, 이는 하악골의 기능변화를 초래하게 된다. 이에 저자는 최근 급증하는 악교정수술환자의 하악골 근육의 생리적 활성도나 하악골의 운동변화를 분석하여 보다 객관적인 술전 및 술후의 평가기준을 제시하고자, Biopak을 이용하여 정상교합자와 하악전돌증을 주소로 내원하여 악교정수술을 시행받은 골격성 III급 부정교합자의 하악기능 양상을 총괄적으로 비교분석하여 다음과 같은 결과를 얻었다. 1. 각 군간의 근활성도 비교시 resting시에는 술전군이 정상군에 비해 더 큰 근활성도를 나타내었고, 수술후 그 측정치가 점차 감소함을 볼 수 있었다. clenching시에는 술전군의 교근과 전측두근의 근활성도가 정상군에 비해 더 감소되어 있었고 수술후 다시 증가하여 수술전과 술후 6개월군 사이에 통계적 유의차가 관찰되었다. 2. 각 근육 활성 도간의 비교시 resting시에는 전측두근의 활성도가 나머지 근육에 비해 다소 증가된 양상을 보였으나 통계적 유의차는 없었고, clenching시에는 모든 group에서 전측두근과 교근의 활성도가, swallowing시에는 악이복근의 활성도가 통계적 유의차를 보이며 크게 나타났다. 3. 하악운동범위의 비교시 전반적으로 술전군에서 제한된 운동 범위를 나타내었으며 최대개구량은 술후 6개월에, 전방운동량은 술후 3개월에 유의성 있는 증가를 보였다.