Three-dimensional quantitative assessment of surgical stability and condylar displacement changes after counterclockwise maxillomandibular advancement surgery: Effect of simultaneous articular disc repositioning.

INTRODUCTION: In this study, we quantitatively assessed 3-dimensional condylar displacement during counterclockwise maxillomandibular advancement surgery (CMMA) with or without articular disc repositioning, focusing on surgical stability in the follow-up period. METHODS: The 79 patients treated with CMMA had cone-beam computed tomography scans taken before surgery, immediately after surgery, and, on average, 15 months postsurgery. We divided the 142 condyles into 3 groups: group 1 (n = 105), condyles of patients diagnosed with symptomatic presurgical temporomandibular joint articular disc displacement who had articular disc repositioning concomitantly with CMMA; group 2 (n = 23), condyles of patients with clinical verification of presurgical articular disc displacement who had only CMMA; and group 3 (n = 14), condyles of patients with healthy temporomandibular joints who had CMMA. Presurgical and postsurgical 3-dimensional models were superimposed using voxel-based registration on the cranial base. Three-dimensional cephalometrics and shape correspondence were applied to assess surgical and postsurgical displacement changes. RESULTS: Immediately after surgery, the condyles moved mostly backward and medially and experienced lateral yaw, medial roll, and upward pitch in the 3 groups. Condyles in group 1 showed downward displacement, whereas the condyles moved upward in groups 2 and 3 (P ≤0.001). Although condylar displacement changes occurred in the 3 groups, the overall surgical procedure appeared to be fairly stable, particularly for groups 1 and 3. Group 2 had the greatest amount of relapse (P ≤0.05). CONCLUSIONS: CMMA has been shown to be a stable procedure for patients with healthy temporomandibular joints and for those who had simultaneous articular disc repositioning surgery.

Laser versus ultrasound on bone density recuperation after distraction osteogenesis-a cone-beam computer tomographic analysis.

PURPOSE: To assess the effects of low-level laser versus ultrasound irradiation on bone mineral density after distraction osteogenesis using cone-beam computed tomographic analysis in an experimental study. MATERIALS AND METHODS: Distraction osteogenesis was performed with rapid maxillary expansion devices (Hyrax-Morelli, Sorocaba-São Paulo-Brazil). After a 2-day latency period, the distraction devices were activated for 10 days at a rate of 1 mm/day. Four groups of 6 animals were distributed as follows: 1) control, 2) laser irradiation on the right side, 3) ultrasound irradiation on the right side, and 4) laser irradiation on the right side and ultrasound on the left side. Cone-beam computed tomography was used to determine bone mineral density by measuring the recovery (percentage). Analysis of variance and the Tukey test (P = .05) were used for statistical analyses. RESULTS: The influences of low-intensity laser and ultrasound irradiation on bone mineral density were statistically significant. The analyses showed greater bone mineral density recuperation in the mandibular side with the ultrasound application. CONCLUSIONS: The results of this study suggest an acceleration of bone mineral density after laser and ultrasound irradiation. Ultrasound irradiation showed the greatest effects and the laser power positively influenced the recuperation of the bone density on the side opposite its application, causing a cross reaction or even exacerbating the inherent action of ultrasound irradiation.