Residues persistence analysis of intracanal dressing with silver-containing solution using electron microscopy and its effect in push-out bond strength of an epoxy-based sealer in radicular dentin

• Grant number: 12/15202-5
• Support type: Scholarships in Brazil - Scientific Initiation
• Effective date (Start): November 01, 2012
• Effective date (End): October 31, 2013
• Field of knowledge: Health Sciences - Dentistry - Dental Clinics
• Principal researcher: Milton Carlos Kuga
• Grantee: Julia Puppin Rontani
• Home Institution: Faculdade de Odontologia (FOAr). Universidade Estadual Paulista (UNESP). Campus de Araraquara. Araraquara , SP, Brazil

Abstract

The aim of this study is investigate the effect of the use of silver solution on radicular dentin in two evaluation periods, through the analysis of precipitates and its effect on push-out bond strength of an epoxy-based cement. To residues persistence test, the root canals will be instrumented to F5 (ProTaper) instrument, irrigated with 2.5% NaOCl and 17% EDTA. In sequence, the teeth will be divided into six experimental groups (n = 10), according to the concentration and persistence time of the intracanal dressing with silver-containing solution. A F5 absorbent paper point impregnated with a solution will be placed into root canal, maintained in the respective time, following groups: group 1 - saline for 24 h; G2 - 12% diamine silver-fluoride for 72 h; G3 - 12% diamine silver-fluoride for 24 h; G4 - 12% diamino-silver fluoride for 72 h; G5 - 3.8% diamino-fluoride and for, 24 h and G6 - 3.8% diamino-silver fluoride for 72 h. In groups of 72 h, the medication will be changed in each 24 h. After use of the medication being tested, the roots will be cleaved in the bucco-lingual and a hemisection of each root is processed for EDX and SEM. Images of each specimen will be obtained in a 500X, the cervical segment of the apical-middle and middle-to evaluate the presence of residues of silver. The presence of residues will be determined through scores. Data will be submitted to the Kruskal-Wallis test (± = 5%). To evaluate the interference of the residues of intracanal medication in the adhesion of the sealer to dentin conditioned, will be used to test push-out. Sixty roots of freshly extracted human teeth of the root anatomy similar will be used. The canals will be instrumented to F5 instrument (ProTaper) and prepared identically to previous study. After conclusion of the chemical-mechanical preparation, the specimens are divided into six groups similarly as described above. After the intracanal medication phase, the canals will be filled with an epoxy-based cement. The roots are then sectioned transversely to the long axis root obtaining a specimen of each third of the root, which will be submitted to the push-out test, in a universal testing machine, with a load of 5 kN and a speed of 0.5 mm/min. The force required to displace the material will be converted in MPa. Data will be submitted to ANOVA test (± = 5%). The fracture type in the specimens will be classified as cohesive, adhesive and mixed, after each root slice to be examined with a stereomicroscope at 30X..