RESUMO
Abstract This study aimed to investigate whether two acquisition parameters, voxel size and filter thickness, used in a micro-computed tomography (micro-CT) scan, together with the examiner's experience, influence the outcome of bone repair analysis in an experimental model. Bone defects were created in rat tibiae and scanned using two voxel sizes of 6- or 12-µm and two aluminum filter thickness of 0.5- or 1-mm. Then, bone volume fraction (BV/TV) and trabecular thickness (Tb.Th) were analyzed twice by two groups of operators: experienced and inexperienced examiners. For BV/TV, no significant differences were found between scanning voxel sizes of 6 and 12 µm for the experienced examiners; however, for the inexperienced examiners, the analysis performed using a 12-µm voxel size resulted in higher BV/TV values (32.4 and 32.9) than those acquired using a 6-µm voxel size (25.4 and 24.8) (p < 0.05). For Tb.Th, no significant differences between the analyses performed by experienced and inexperienced groups were observed when using the 6-µm voxel size. However, inexperienced examiners' analysis revealed higher Tb.Th values when using the 12-µm voxel size compared with 6 µm (0.05 vs. 0.03, p < 0.05). Filter thickness had no influence on the results of any group. In conclusion, voxel size and operator experience affected the measured Tb.Th and BV/TV of a region with new bone formation. Operator experience in micro-CT analysis is more critical for BV/TV than for Tb.Th, whereas voxel size significantly affects Tb.Th evaluation. Operators in the initial phases of research training should be calibrated for bone assessments.
RESUMO
Abstract This systematic review evaluated the potential utility of platelet-rich fibrin (PRF) in bone repair in animals. The question is: can the use of PRF in bone defects in healthy rats induce bone repair compared to clot? This systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (Prisma). The protocol was registered with Prospero (CRD [42020162319]). The literature search involved nine databases, including grey literature. All studies evaluated the bone defects created in rats filled with PRF and clots (control). Biomaterial evaluation was also performed in this study. The risk of bias was assessed using the Systematic Review Center for Laboratory Animal Experimentation (Syrcle) tool for animal studies. A meta-analysis of quantitative data was performed to estimate the effect of PRF on bone repair in rats. Heterogeneity among the studies was assessed using the I2 statistic. The literature search retrieved 685 studies, 10 of which fulfilled the eligibility criteria, and 4 were included in the quantitative assessment. Analysis of the risk of bias revealed that most studies had a high risk of bias in performance and detection. Meta-analysis yielded divergent results and the absence of a statistically significant effect: PRF with control (standardized mean difference 2.54, 95% confidence interval -0.80-5.89; p = 0.14). In general, study heterogeneity was high (I2 ≥ 75.0%). The quality of the studies that influenced the conclusion of the review was based on the PICO, the sources and form of the search, the study selection criteria, the form of evaluation of publication bias, the evaluation of the quality of the studies, and data extraction by two researchers. PRF did not provide significant benefits for bone repair, resulting in unpredictable effects.