MicroCT analysis of the influence of different endodontic retreatment protocols on filling material removal in flattened root canals and their impact on bond strength of epoxy resin-based sealer

• Grant number: 19/27116-5
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: March 01, 2020
• End date: May 31, 2021
• Field of knowledge: Health Sciences - Dentistry - Endodontics
• Principal Investigator: Fuad Jacob Abi Rached Junior
• Grantee: Orestes Pereira Olivato
• Host Institution: Universidade de Ribeirão Preto (UNAERP). Campus Ribeirão Preto. Ribeirão Preto , SP, Brazil

Abstract

The aim of the present study will be to evaluate, using computerized microtomography (microCT), different complementary protocols for the removal of the obturator material in flattened root canals, and the impact of the remnant on the dentin adhesion of AH Plus sealer, by the push out test. Fifty flattened pre molar roots will be selected by microCT morphological analysis. After biomechanical preparation with Reciproc R25 system the roots will be filled by lateral condensation with AH Plus and gutta-percha. Ten specimens will be randomly selected for the control group, which will not undergo endodontic retreatment. The specimens will be thermocycled and then scanned again and quantitatively evaluated for the volume of the endodontic filling material. Removal of the endodontic filling material from the remaining specimens will be performed by the R40 instrument and distributed in groups according to the protocol for the removal of the filling material (n=40): Reciproc/ conventional irrigation, Reciproc/ passive ultrasonic irrigation, Reciproc/ EasyClean. The specimens will be escanned again and quantitatively evaluated for the remaining volume of the obturator material. The specimens will be filled again using the lateral condensation technique with AH Plus sealer and gutta-percha, and then cut into 2mm slices in a cutting machine. The first slice of each third will be submitted to the push-out test and the second slice of each third will be submitted to scaning electron microscopy for the ananlysis of the filling material/ dentin interface. The morphometric data (mm3) of the microtomography and the values (MPa) of the bond strength will be submitted to statistical analysis using the SPSS program.