Postoperative stability of conventional bimaxillary surgery compared with maxillary impaction surgery with mandibular autorotation for patients with skeletal class II retrognathia.

We aimed to compare the postoperative stability of conventional bimaxillary surgery (with bilateral sagittal split osteotomy) with that of maxillary impaction surgery (with mandibular autorotation without bilateral sagittal split osteotomy) in patients with skeletal class II retrognathia. Patients were assigned to have conventional bimaxillary surgery (conventional group, n=6) or mandibular autorotation (experimental group, n=7). Measurements were made using serial lateral cephalometric radiographs taken immediately preoperatively (T0), immediately postoperatively (T1), and one year later (T2) to assess the variation in operative change (T1-T0) and relapse (T2-T1). There was no significant difference in median (range) surgical change in the anterior movement at point B (conventional group, 4.5 (3.0-11.0) mm; experimental group 4.1 (2.1-6.4) mm). However, there was a significant difference in median (range) surgical posterior movement relapse at point B (conventional group -1.7 (-2.3 to -0.5) mm; experimental group -0.6 (-1.0 to 1.0) mm; p=0.032). Mandibular advancement with mandibular autorotation is therefore a more stable procedure than mandibular advancement with bilateral sagittal split osteotomy in patients with skeletal class II retrognathia.

Low-intensity pulsed ultrasound stimulation for mandibular condyle osteoarthritis lesions in rats.

OBJECTIVE: This study evaluated low-intensity pulsed ultrasound effects for temporomandibular joint osteoarthritis in adult rats. MATERIAL AND METHODS: Osteoarthritis-like lesions were induced in 24 adult rats' temporomandibular joints with low-dose mono-iodoacetate injections. The rats were divided into four groups: control and mono-iodoacetate groups, injected with contrast media and mono-iodoacetate, respectively, at 12 weeks and observed until 20 weeks; and low-intensity pulsed ultrasound and mono-iodoacetate + low-intensity pulsed ultrasound groups, injected with contrast media and mono-iodoacetate, respectively, at 12 weeks with low-intensity pulsed ultrasound performed from 16 to 20 weeks. Condylar bone mineral density, bone mineral content and bone volume were evaluated weekly with microcomputed tomography. Histological and immunohistochemical staining for matrix metalloproteinases-13 was performed at 20 weeks. RESULTS: At 20 weeks, the mono-iodoacetate + low-intensity pulsed ultrasound group showed significantly higher bone mineral density, bone mineral content and bone volume than the mono-iodoacetate group; however, these values remained lower than those in the other two groups. On histological and immunohistochemical analysis, the chondrocytes were increased, and fewer matrix metalloproteinases-13 immunopositive cells were identified in the mono-iodoacetate + low-intensity pulsed ultrasound group than mono-iodoacetate group. CONCLUSIONS: Low-intensity pulsed ultrasound for 2 weeks may have therapeutic potential for treating temporomandibular joint osteoarthritis lesions.