ANALYSIS WITH X-RAY MICROTOMOGRAPHY OF THE BONE VOLUME IN AN EXPERIMENTAL ORTHODONTICS MODEL

Introduction: The orthodontic forces that trigger the processes of resorption and neoformation of bone tissue have been widely studied, but we have not found reports that study this movement towards a recent post-extraction alveolus. In previous studies, we were able to check the block movement of the first lower molar towards the post-extraction alveolus after the application of an orthodontic force. Objective: to study the bone volume in relation to the first lower molar with X-ray microtomography, after the application of orthodontic forces towards a post-extraction alveolus. Methodology: 12 Wistar rats of 200 ± 50 g, distributed in: (A) control, (B) orthodontics and (C) orthodontics + orthodontics. Groups B and C underwent the exodontics of the lower left 2nd molar. An experimental orthodontic device was installed in group C animals immediately after the molar extraction. At 7 days, all groups underwent euthanasia and resection of both lower hemimaxillars. The samples were fixed in 10% formalin. Images were obtained with an X-ray microtomograph (Bruker Skyscan 1272), with a voltage / current of 70 Kv / 142 µA and resolution of 8.3 µm. The CTan software was used to calculate 3D structural parameters. The following information was evaluated: Tissue volume TV mm³, Bone volume BV mm³, Percent bone volume BV / TV%. The values ??were analyzed with ANOVA and Student Newman Keuls. Results: TV did not show differences since it refers to the selected area (A; 2.94, B: 2.43 and C: 2.98 mm³) BV was lower in C than in B and both lower than A with significant differences (A: 1.27, B: 0.87 and C: 0.54 mm³), since the percentage of interradicular bone volume is a relationship between TV and BV the differences are also significant. Conclusion: the results confirm that tooth movement is performed at the expense of bone resorption.