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The effect of association of low-level laser irradiation and poly(vinylidene-trifluoroethylene)/barium titanate composite in the repair of bone defects in calvaria of ovariectomized rats.


Osteoporosis is a disease that compromises the strength and quality of bone tissue. Different methodologies in the field of dentistry have been used in search of bone repair in the face of this disease that can predispose to periodontal diseases, accelerating the loss of alveolar bone. Low-level laser therapy is a methodology that has been used in the search for new bone formation. Different times, number of applications, wavelengths and energy densities have been studied. Another methodology is guided tissue regeneration. In vitro and in vivo experiments have demonstrated favorable results of the use of the membrane obtained by the association of poly(vinylidene-trifluoroethylene) polymer and barium titanate ceramics (P (VDF-TrFE) / BT) when compared to the polytetrafluoroethylene membrane (PTFE). Thus, this study aims to evaluate in vivo the response of bone tissue to low-level laser irradiation when associated with PTFE (control) and P(VDF-TrFE)/BT membranes in bone defects in calvaria of rats with experimental model to osteoporosis. Female Wistar rats (300g) will undergo the simulation of ovariectomy surgery (Group 1 - Sham; n=5) and will be bilaterally ovariectomized (n=35). After 90 days, bone defects (5 mm) will be performed on calvaria and the ovariectomized animals will be divided into four groups: Group 2 - without membrane and without laser application (n=5); - Group 3 - P(VDF-TrFE)/BT membrane (n=10); Group 4 - P(VDF-TrFE)/BT membrane + laser application (n=10); Group 5 - PTFE membrane + laser application (n=10). The gallium-aluminum arsenide (GaAlAs) diode will be used with a wavelength of 780 nm and energy density or fluence of 30J/cm2 (12 sessions). At the end of thirty days after bone defect creation, the animals will be sacrificed and will be carried out as follows: (1) tomographic analysis (micro-CT) of the defects previously created, (2) histological analysis in non-decalcified histological sections, (3) the mRNA expression of runt-related transcription factor 2 (RUNX2), alkaline phosphatase (ALP), bone sialoprotein (BSP), osteocalcin (OC), osteopontin (OPN), osterix (OSX), receptor activator of nuclear factor kappa B ligand (RANKL), osteoprotegerin (OPG), receptor activator of nuclear factor-kappa B (RANK), Cathepsin K and matrix metalloproteinase-9 (MMP-9) by real-time PCR. Statistical tests to analyze the numerical results will be selected according to the distribution of samples. (AU)