Use of bioresin membrane in critical bone defects. Microtomographic and histomorphometric study on rat calvaria.

Abstract

The objective of this pre-clinical study is to evaluate the properties of guided bone regeneration and the biodegradation process of a new membrane, printed in resin and developed from Acrylated Epoxidized Soybean Oil (AESO), on critical bone defects made in calvaria of rats. Comparative microtomographic, histological and histomorphometric analyzes of bone regeneration and xenograft incorporation will be carried out with or without the use of the membrane. Third six (36) adult male Sprague Dawley rats will be used, weighing, on average, 250g, provided by the Central Animal Facility of the University of São Paulo. In each animal, a critical bone defect of 7 mm in diameter will be created on the parietal bone, using a trephine drill. The 03 groups will be composed of 12 animals each, divided into two experimental times of 04 and 08 weeks (n=6), with a negative control group (clot only), positive control (only biomaterial / xenograft OsteoBiol® GTO (Tecnoss, Giaveno , Italy) and the test group where the bone defects will be filled with biomaterial and covered by the bioresin membrane developed for the study. After the experimental periods of 04 and 08 weeks, euthanasia will be carried out and biopsies will be collected from the operated sites. will be sent for scanning and microtomographic analysis to evaluate the parameters: bone volume (BV), bone volume/tissue volume (BV/TV), bone surface (BS), bone surface/tissue volume (BS/TV), trabecular thickness (TB .Th), number of trabeculae (Tb.N) and trabecular spacing (Tb.S). Subsequently, histological processing and inclusion in resin and cutting will be carried out using cutting/precision equipment (Exakt, Apparatebau, Norderstedt, Germany) and preparation of histological slides stained Stevenel's Blue and Alizarin Red. The following will be evaluated: percentage of new mineralized bone , xenograft remnant, connective tissue, inflammatory cells, osteoclasts, vessels and membrane residues. Bone volume in microtomographic analysis and bone percentage in histomorphometric analysis are primary variables. Differences between groups will be evaluated using the one-way ANOVA test. The Shapiro-Wilk test will be used to determine the normality of the data and, according to the results, the differences between the test and control sides will be evaluated by paired t-test or Wilcoxon matched pairs signed rank test. GraphPad Prism (version 10.0.0 for Windows, GraphPad Software, San Diego, California, USA, www.graphpad.com) will be used for statistical analysis. The significance level will be 5%.