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Abstract Objective the aim of this study was to analyze the influence of ozone therapy (OZN) on peri-implant bone repair in critical bones by installing osseointegrated implants in the tibia of ovariectomized rats. Methodology ovariectomy was performed on 30 Wistar rats, aged six months (Rattus novergicus), and, after 90 days, osseointegrated implants were installed in each tibial metaphysis. The study groups were divided into the animals that received intraperitoneal ozone at a concentration of 700 mcg/kg — OZ Group (n=15) — and a control group that received an intraperitoneal saline solution and, for this reason, was named the SAL group (n=15). The applications for both groups occurred during the immediate post-operative period on the 2nd, 4th, 6th, 8th, 10th, and 12th day post-surgery. At various stages (14, 42, and 60 days), the animals were euthanized, and tests were performed on their tibiae. These tests include histomorphometric and immunohistochemical analyses, computerized microtomography, sampling in light-cured resin for calcified sections, and confocal microscopy. The obtained data were then analyzed using One-way ANOVA and the Shapiro-Wilk, Kruskal-Wallis, and student t-tests (P<0.05). Results our findings indicate that the OZ group (3.26±0.20 mm) showed better cellular organization and bone neoformation at 14 days (SAL group, 0.90±1.42 mm) (P=0.001). Immunohistochemistry revealed that osteocalcin labeling was moderate in the OZ group and mild in the SAL group at 14 and 42 days post-surgery. The data from the analysis of calcified tissues (microtomography, histometric, and bone dynamism analysis) at 60 days showed no statistically significant differences between the groups (P=0.32). Conclusion it was concluded that ozone therapy anticipated the initial phases of the peri-implant bone repair process.
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Abstract Objective To choose a critical animal model for assessments of bone repair with implant installation by comparing senile rats (SENIL) to young ovariectomized rats (OXV). Methodology For the ex-in vivo study, the femurs were precursors for bone marrow mesenchymal stem cells. Cellular responses were performed, including cell viability, gene expression of osteoblastic markers, bone sialoprotein immunolocalization, alkaline phosphatase activity, and mineralized matrix formation. For the in vivo study, the animals received implants in the region of the bilateral tibial metaphysis for histometric, microtomography, reverse torque, and confocal microscopy. Results Cell viability showed that the SENIL group had lower growth than OVX. Gene expression showed more critical responses for the SENIL group (p<0.05). The alkaline phosphatase activity obtained a lower expression in the SENIL group, as for the mineralization nodules (p<0.05). The in vivo histological parameters and biomechanical analysis showed lower data for the SENIL group. The confocal microscopy indicated the presence of a fragile bone in the SENIL group. The microtomography was similar between the groups. The histometry of the SENIL group showed the lowest values (p<0.05). Conclusion In experimental studies with assessments of bone repair using implant installation, the senile model promotes the most critical bone condition, allowing a better investigation of the properties of biomaterials and topographic changes.