The present study aimed to evaluate the effects of LLLT (660- and 808-nm wavelengths) on the process of repairing bone defects induced in the femurs of female rats submitted to ovariectomy. Bilateral ovariectomies were performed on 18 female Wistar rats, which were divided into control and irradiated groups after the digital analysis of bone density showed decreased bone mass and after standardized drilling of the femurs. The irradiated groups received 133 J/cm(2) of AsGaAl (660-nm) and InGaAlP (880-nm) laser radiation. The animals were euthanized on days 14 and 21 after the bone defects were established. Detailed descriptive histological evaluations were performed, followed by semi-quantitative histomorphometry. The results from days 14 and 21 showed that the irradiated groups presented increased density of osteoblasts, fibroblasts, and immature osteocytes on the tissue surface compared with the control (non-irradiated) groups (p < 0.05). Additionally, inflammatory infiltrate evaluations showed that LLLT decreased the accumulation of leukocytes when compared to the control treatment (p < 0.05). We concluded that, in our experimental model, both wavelengths (660-nm and 880-nm) inhibited the inflammatory process and induced the proliferation of cells responsible for bone remodeling and repair.

PURPOSE: To evaluate the biologic behavior of the castor polymer containing silica nanoparticles as a bone substitute in diafisary defect. METHODS: Twenty seven male rattus norvegicus albinus wistar lineage were submitted to bone defect filled with castor oil polymer. Three experimental groups had been formed with nine animals each: (1) castor oil polymer containing only calcium carbonate; (2) castor oil polymer with calcium carbonate and doped with 5% of silica nanoparticles; (3) castor polymer with calcium carbonate doped with 10% of silica nanoparticles; 3 animals of each group were submitted to euthanasia 15, 30 and 60 days after experimental procedure, and their femurs were removed to histological evaluation. RESULTS: there was bone growth in all the studied groups, with a greater tendency of growth in the group 1. After 30 days all the groups presented similar results. After 60 days a greater amount of fibroblasts, osteoblasts, osteocytes and osteoclasts in group 3 was observed, with integrated activity of 3 kinds of cells involved in the bone activation-reabsorption-formation. CONCLUSIONS: The castor polymer associated to the silica nanoparticles is biocompatible and allows osteoconduction. The presence of osteoprogenitors cells suggests silica osteoinduction capacity.

PURPOSE:To evaluate the biocompatibility and osteogenesis of castor oil polymer doped with SiO 2 or BaTiO 3 nanoparticles. METHODS:Twenty four male rats Wistar were submitted to bone defect filled with castor oil polymer. The animals were distributed in RESULTS:The implants were biocompatible and allowed for progressive osteogenesis through osteoconduction in both observation periods. There was significant bone neoformation at 30 and 60 days in both groups within the histomorphometric evaluation, but group 1's osteogenesis was lesser in the 30 and 60-day periods observed when compared to the animals of group 2. The MEV morphometric evaluation evidenced a lesser percentage of osseous tissue filling within the BaTiO2-doped polymer. CONCLUSION:The castor oil polymer doped with SiO2 or BaTiO3 remained biocompatible and allowed for progressive osteogenesis in both observation periods.