Comparison study of the Le Fort I osteotomy using 2- and 4-plate fixation.

This study was conducted to evaluate the postsurgical stability of Le Fort I osteotomy using zygomatic buttress internal fixation alone with no piriform aperture internal fixation. Patients with maxillary retrognathia and mandibular prognathism underwent the Le Fort I osteotomy with a bilateral sagittal split ramus osteotomy. In group I, fixation was accomplished using titanium plate and screws placed at the piriform aperture and the zygomatic buttress (4 plates). In group II, fixation was accomplished using titanium plate and screws placed at the zygomatic buttress (2 plates). Lateral cephalometric radiographs were taken preoperatively (T1), immediately after surgery (T2), and at 6 months to 1 year (T3) to evaluate skeletal movement. In total, 32 patients were included in this study. None of the patients had wound infection, dehiscence, bone fragment instability, and long-term malocclusion. Regarding point A and the posterior nasal spine (PNS), vertical and horizontal relapse in groups I and II did not differ significantly. In most hospitals, the maxilla was fixed using four plates (piriform aperture and zygomatic buttress); however, within the limitations of the study, the choice of the number of plates for osteosynthesis following Le Fort I osteotomy and repositioning of the maxilla can be left to the discretion of the surgeon without putting the patients at risk for increased relapse by careful intraoperative management.

Conditioned media from mesenchymal stromal cells and periodontal ligament fibroblasts under cyclic stretch stimulation promote bone healing in mouse calvarial defects.

BACKGROUND AIMS: When cells are exposed to stresses such as mechanical stimuli, they release growth factors and adapt to the surrounding environment H ere, we demonstrated that mechanical stimulation during culture affects the production of osteogenic and angiogenic factors. METHODS: Human bone marrow derived mesenchymal stromal cells (hMSCs) and human periodontal ligament fibroblasts (HPLFs ) were cultured under cyclic stretch stimulation for 24 h. Collected of the cells and conditioned media (CM), the gene and protein expression levels of osteogenic and angiogenic factors were evaluated. CM was also evaluated for angiogenic activity and calc ification ability. In in vivo study, CM was administered to a mouse calvarial defect model and histologically and radiologically evaluated. RESULTS: Quantitative real time polymerase chain reaction results showed that the expression of bone morphogenetic pro tein 2, 4 (BMP 2, 4), vascular endothelial growth factor A (VEGF A), and platelet derived growth factor AA (PDGF AA) was upregulated in the cyclic stretch stimulation group in comparison with the non stretch group in each cell type. Enzyme linked immunosor bent assay results revealed that the expression of BMP 2,4, VEGF A was upregulated in the cyclic stretch group in comparison with the non stretch group in each cell type. Only HPLFs showed significant difference in PDGF AA expression between the cyclic str etch and the non stretch group. Tube formation assay and Alizarin Red S staining results showed that angiogenic activity and calcification ability of CM was upregulated in the cyclic stretch stimulation group in comparison with the non stretch group in eac h cell type. CM was administered to the mouse calvarial defect model. Histological and radiological examination showed that the bone healing was promoted by CM from the cyclic stretch culture group. Immunohistological staining revealed that CM from cyclic stretch group have greater angiogenic effect than CM from the non stretch group. CONCLUSIONS: These results indicate that osteogenesis was promoted by CM obtained under cyclic stretch stimulation through the increase of angiogenesis in the mouse calvarial defect model.

A Mouse Distraction Osteogenesis Model.

Distraction osteogenesis (DO) is a surgical procedure that involves skeletal tissue regeneration without cell transplantation. A DO model consists of the following three phases: the latency phase after osteotomy and placement of the external distractor; the distraction phase, wherein the separated bone ends are gradually and continuously distracted; and the consolidation phase. This custom-made distractor used for DO is comprised of two incomplete acrylic resin rings and an expansion screw. The process was initiated by making a mold with silicone impression material and then creating the custom-made distractor. Dental resin was poured into the formwork made of silicone impression material, and it was allowed to polymerize to create the incomplete resin rings required for the custom-made distractor. These rings were fixed with an expansion screw using transparent resin. The custom-made distractor created via this approach was attached to the tibia of mice. The tibia was fixed to the device using one pair of 25 G needles proximally, one pair of 27 G needles distally, and acrylic resin. After a latency period of 5 days, distraction was initiated at a rate of 0.2 mm/12 h. The lengthening was continued for 8 days, resulting in a total gap of 3.2 mm. The mice were sacrificed 4 weeks after distraction. Bone formation in the distraction gap was confirmed using both radiography and histology.