The three-dimensional assessment of dynamic changes of the proximal segments after intraoral vertical ramus osteotomy.

OBJECTIVES: The aim of this study was to assess the positional changes of the proximal segments after intraoral vertical ramus osteotomy (IVRO). METHOD: Fifteen patients underwent IVRO and were followed according to the authors' unique postoperative management regimen. The analyses of the positions and angles of the proximal segments were performed on frontal and lateral cephalograms, which were taken before surgery (T1) and within 3 days (T2), at 4 weeks (T3), and later than 6 months after surgery (T4). The three-dimensional positions of the condylar heads were also assessed by CT images, which were taken before and 1 year after surgery. RESULTS: The proximal segments temporarily swung posteriorly and laterally with a center on the condylar head as a fulcrum point at T2 and T3, compared with T1, and they repositioned at T4. The condylar heads moved inferior approximately 2 mm with lateral rotation one year after surgery, as seen in the CT. DISCUSSION: The condylar heads changed their positions physiologically for newly established jaw movement after IVRO with the authors' post-operative management regimen because the post-operative skeletal stability and the jaw function were good and stable using this method.

The skeletal stability after maxillo-mandibular osteotomy with a "physiological positioning strategy".

The aim of this study was to estimate skeletal and dental stability after maxillomandibular osteotomy with physiological positioning. Ten patients (7 men and 3 women) with skeletal mandibular prognathism were treated by conventional Le Fort I osteotomy for the maxilla and unfixed short lingual osteotomy for the mandible together with physiological positioning. We used cephalometric analysis to evaluate the skeletal and dental stability preoperatively, immediately after maxillomandibular osteotomy, and more than 1 year later. The immediately postoperative measurements for the SNA and the SN-palatal planes were 0.15° (p=0.67) and 1.0° (p=0.17), respectively. The positions of the anterior nasal spine, posterior nasal spine, and A point showed minimal changes 1 year postoperatively. The postoperative difference for SNB was 0.76° (p=0.04). Dental stability was apparent postoperatively. We conclude that reliable stability of both the maxilla and the mandible was achieved after maxillomandibular osteotomy with physiological positioning in patients with mandibular prognathism.

Short lingual osteotomy without fixation: a new strategy for mandibular osteotomy known as "physiological positioning".

We describe the strategy of physiological positioning, which we regard as a new alternative treatment to conventional orthognathic operations, and treated 18 patients with skeletal mandibular prognathism using it. The positions of SNB, FMA, and Me were measured postoperatively to assess skeletal stability, changes in the angle and perpendicular length of the upper and lower central incisors were measured to assess dental stability, and we confirmed that both skeletal and dental stability were excellent. The width to which the jaw could be opened recovered early, and we saw only one case of disorder of the temporomandibular joint. Short lingual osteotomy with physiological positioning is an effective new approach to the treatment of deformities of the mandible.

Ameloblastic fibrodentinoma with a congenitally missing second premolar tooth: a case report.

Ameloblastic fibrodentinoma (AFD) is a rare benign mixed odontogenic tumor that occurs predominantly in children and young adults. AFD is usually associated with delayed eruption of the tooth and shows painless swelling. We present a case of AFD affecting an 8-year-old Japanese girl with a complaint of delayed eruption of her left mandibular second premolar tooth. Intraoral examination did not reveal any sign of pain or swelling in the left mandible. Panoramic radiography revealed a radiolucent and well-circumscribed lesion, which contained radiopaque material at the premolar lesion of the left mandible. The second deciduous molar tooth was unerupted and the second premolar tooth was congenitally lacking. Our provisional diagnoses were odontogenic tumor. The biopsy confirmed AFD. The treatment included total excision of the tumor and the second premolar tooth. No recurrence has been noted during the 2 years of follow-up.

Assessment of skeletal stability of intraoral vertical ramus osteotomy with one-day maxillary-mandibular fixation followed by early jaw exercise.

PURPOSE: Intraoral vertical ramus osteotomy (IVRO) is an effective surgical technique for cases of mandibular setback, is simpler and has a lower incidence of mental paraesthesia when compared to sagittal split ramus osteotomy (SSRO). However, IVRO has a disadvantage in the prolonged duration of postoperative maxillary-mandibular fixation (MMF) required due to the absence of rigid bone fixation. To avoid an extended MMF period, we developed a postoperative management protocol for our IVRO patients, using jaw exercises with elastic bands starting on the second day after surgery. METHODS: We evaluated the cephalometric skeletal and dental stabilities of 16 IVRO patients as they followed our protocol. RESULTS: The stabilities were confirmed and were similar to those of previous reports. CONCLUSION: One-day MMF and early initiation of jaw exercise after IVRO did not affect the jaw position stability. Moreover, our findings suggest that starting jaw exercise earlier after IVRO surgery is beneficial, as it allows patients to avoid a long period of rigid MMF so that they can resume their normal daily activities sooner.