Interaction between sodium hypochlorite and chlorhexidine: evaluation of cleaning ability and influence on bond strength of a cement containing epoxy resin

• Grant number: 12/09626-7
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date until: September 01, 2012
• End date until: August 31, 2013
• Field of knowledge: Health Sciences - Dentistry - Dental Clinics
• Principal Investigator: Arnaldo Sant Anna Júnior
• Grantee: Juliana Mayume Miyahira
• Host Institution: Faculdades Integradas de Santa Fé do Sul. Fundação Municipal de Ensino e Cultura (FUNEC). Santa Fé do Sul , SP, Brazil

Abstract

The objectives of this study will evaluate the presence of "debris" and "smear layer" on root canal wall and the impact on the bond strength of an epoxy cement in root dentin after final irrigation following protocols as follows: Group 1. 17% EDTA + 5 ml 2.5% sodium hypochlorite + 5 mL of isopropyl alcohol + 5 ml of 2% chlorhexidine, Group 2. 17% EDTA + 5 ml 2.5% sodium hypochlorite + 5 ml of saline solution + 5 ml of 2% chlorhexidine, Group 3. 17% EDTA + 5 ml 2.5% sodium hypochlorite + 5 ml of distilled water + 5 ml of 2% chlorhexidine, Group 4. 17% EDTA + 5 ml 2.5% sodium hypochlorite + 5 ml of 2% chlorhexidine (Positive Control), Group 5. EDTA 17% + 2.5% sodium hypochlorite (negative control). To test for assessing the residual presence of "debris" and "smear layer", fifty single-rooted extracted human teeth have their standardized root length in 16 mm. The canals will be instrumented to instrument F3 (ProTaper), and then divided into five experimental groups (n = 10) described. After drying, the roots will be cleaved in the buccolingual direction, where a hemisection of each root is processed for SEM. Images of each specimen will be obtained in a 200X and 1000X in another, the cervical segment of the apical-middle and middle-to evaluate the presence of debris and smear layer, respectively. The data will be statistically analyzed using Kruskal Wallis test (± = 5%).To evaluate the interference of these substances in the adhesion of the sealer to dentin conditioned, will be used to test push-out. Fifty roots of freshly extracted human teeth of the root anatomy similar will be standardized 16 mm in length. The canals will be extended to the equivalent of F5 instrument (ProTaper) and prepared identically to the previous study. Complete chemical-mechanical preparation, the specimens are divided into five groups according to the above. After the final irrigation canals are filled with a cement-based epoxy resin. The roots are then sectioned obtaining a specimen of each third of the root, which will be tested using the push-out, with a load of 5 kN and 0.5 mm / min. The force required to displace the material will be processed in MPa. The data obtained for each root third shall be submitted to ANOVA test (± = 5%). The type of fracture in the specimens will be classified as cohesive, adhesive and mixed, after obtaining and analyzing the images in stereomicroscopy.(AU)