This study aims to evaluate in vitro resistance to fracture of bovine incisors with different thicknesses of dentin to simulate teeth with incomplete root formation, which will be rehabilitated by two techniques to manufacture intraradicular. Will be used 90 newly extracted bovine incisors. The crowns of the teeth and the tip will be cut leaving 14 mm of root. The pulp tissue is removed with Hedströen # 80 type files. The specimens will be included in PVC pipe with epoxy resin molding material and polyester base to simulate the periodontal ligament. And will be divided into two groups: Group 1 = roots with walls tendo1 mm thick dentin (n = 45) and Group 2: having roots with walls 2 mm thick dentin (n = 45). All thicknesses of the roots will be measured with a digital caliper. Later, the apical 4 mm of root canals are sealed with Coltosol ® and the specimens will be divided into three sub-groups: Group A: Control - untreated fragile roots (n = 15 for Group 1 and n = 15 for Group 2); Group B: weakened roots restored with direct anatomical pin (pin fiber + composite) (n = 15 for Group 1 and n = 15 for Group 2), Group C: weakened roots restored as fiberglass pin only (n = 15 for Group 1 and n = 15 for Group 2). For Groups B and C, the cement MultiLink ® will be used for cementation of intra-radicular retainers. The bodies of the test piece will be tested for resistance to fracture in a universal testing machine with load applied at an angle of 135 degrees with the long axis of the specimen (Moyers, 1975). The values are recorded in N and will be analyzed statistically using ANOVA. The fractures are assessed and classified according to whether post-fracture rehabilitation in favorable and unfavorable.
News published in Agência FAPESP Newsletter about the scholarship: