Facilitating ramus lengthening following mandibular-dependent surgical closing of a skeletal open bite with short ramus: a new modified technique.

Recent studies have shown that a sagittal split ramus osteotomy (SSRO) with counterclockwise rotation of the mandible using rigid fixation is relatively a stable procedure when used to correct a mild skeletal anterior open bite in cases where a maxillary osteotomy is not indicated to improve or enhance facial aesthetics. When an open bite accompanies a short ramus, the closing rotation will result is a large amount of ramus lengthening and downward movement that stretches the major muscle-ligament structures attached to the ramus, with a risk of relapse. In order to overcome this problem we have adopted a modified surgical technique in which a considerable amount of ramus lengthening following mandibular rotating can be achieved. In this paper, the technique will be introduced and illustrated. Advantages and disadvantages will be also discussed.

One-phase vs 2-phase treatment for developing Class III malocclusion: a comparison of identical twins.

Despite the known influence of early treatment on the facial appearance of growing patients with skeletal Class III malocclusion, few comparative reports on the long-term effects of different treatment regimens (1-phase vs 2-phase treatment) have been published. Uncertainty remains regarding the effects of early intervention on jaw growth and its effectiveness and efficiency in the long term. In this case report, we compared the effects of early orthodontic intervention as the first phase of a 2-phase treatment vs 1-phase fixed appliance treatment in identical twins over a period of 11 years. Facial and dental changes were recorded, and cephalometric superimpositions were made at 4 time points. In spite of the different treatment approaches, both patients showed identical dentofacial characteristics in the retention phase. Through this case report, we intended to clarify the benefits of undergoing 1-phase treatment against 2-phase treatment protocols for treating growing skeletal Class III patients.

Biomechanical evaluation of a T-shaped miniplate fixation of a modified sagittal split ramus osteotomy with buccal step, a new technique for mandibular orthognathic surgery.

OBJECTIVE: The purpose of this study was to biomechanically evaluate the stability of a T-shaped miniplate fixation of a modified sagittal split ramus osteotomy (MSSRO) with buccal step and to compare it with single or double-parallel straight miniplates fixing a standard sagittal split ramus osteotomy (SSRO). STUDY DESIGN: Eighteen Synbone mandibular replicas were used in the study and divided into 3 groups. Standard SSRO was applied in the first and second groups, and the third group was cut for MSSRO with buccal step. After 7 mm of advancement, fixation modalities for the 3 groups included a single straight miniplate, double-parallel straight miniplates, and a T-shape miniplate, respectively. Each model was secured in a jig and subjected to vertical load on the anterior teeth. RESULTS: The T miniplate group showed a significantly higher value for stability than the group with a single straight miniplate. There was no significant difference in stability between the T miniplate and the double-parallel straight miniplate groups. CONCLUSION: For mandibular advancement surgery of 7 mm in a laboratory environment, a T-shaped miniplate used with MSSRO and buccal step as a combination significantly optimize the resistance and stability of the fixation compared with a standard SSRO fixed with a single straight miniplate.

Evaluation of skeletal stability after surgical-orthodontic correction of skeletal open bite with mandibular counterclockwise rotation using modified inverted L osteotomy.

PURPOSE: To evaluate the surgical-orthodontic stability of treating skeletal open bite patients with mandibular ramus osteotomies using a modified inverted L osteotomy (M-ILO) and counterclockwise rotation of the mandible stabilized with rigid fixation. PATIENTS AND METHODS: In a retrospective review, 12 patients with skeletal open bites (8 females, 4 males) who received mandibular M-ILO in the period 2004-2007 at Tohoku University Hospital were studied. Lateral cephalograms were taken immediately before surgery (T1), immediately after surgery (T2), and at 1 yr after surgery (T3). Cephalometric analysis for point B, pogonion, menton, and mandibular plane angle was obtained at the designated time intervals. RESULTS: Mandibular counterclockwise rotation showed stability for point B, pogonion, and menton referred to X-Y coordinate, and for mandibular plane angle. The mean value for each variable was compared between T2 and T3. No statistically significant change was observed for all variables. CONCLUSIONS: With a well-positioned maxilla, skeletal open bite can be successfully treated using M-ILO. Mandibular counterclockwise rotation showed stability at 1 yr after surgery.