Influence of different irrigation protocols on bond strength and longevity of anatomic posts using a self-adhesive resin cement

Author(s)

Daniela Cristina Miyagaki

• Document type: Doctoral Thesis
• Press: Piracicaba, SP.
• Institution: Universidade Estadual de Campinas (UNICAMP). Faculdade de Odontologia de Piracicaba
• Defense date: 2014-01-07

Examining board members

Caio Cezar Randi Ferraz; Bruno Carlini Junior; José Flávio Affonso de Almeida; Regina Maria Puppin Rontani; Marcia Carneiro Valera

• Advisor: Caio Cezar Randi Ferraz

Abstract

The present study aimed to analyze in vitro the influence of different irrigation protocols in the adhesive strength and longevity of relined fiberglass posts cemented with self-adhesive resin cement (single chapter). Ninety-six bovine root canals were instrumented with the aid of #6 largo drills, and were randomly divided into 8 groups (n=12) according to the different treatments in radicular dentin: G1 (control)-0.9% saline solution (NaCl); G2- 5.25% sodium hypochlorite (NaOCl) + 17% EDTA + NaOCl; G3- NaOCl + 17% EDTA + NaOCl+ 10% sodium ascorbate (SA); G4- 2% chlorhexidine gluconate gel (CHX) + NaCl + 17% EDTA; G5-NaOCl; G6- 17% EDTA; G7- SA and G8-CHX. After irrigation protocols, the root canals were dried and the fiberglass posts were modeled with resin composite and cemented with RelyX U100 ®. Each group was divided into two subgroups: 24 hours and 12 months of water storage. After storage periods, all roots were sectioned transversely producing 4 slices of 2-mm-thick in order to be subjected to the push-out test. The data obtained in Newton were converted in Megapascal, afterwards the results were analyzed by Shapiro-Wilk, Anova and Tukey's test (P=0.05). Subsequently, the failure pattern was classified using a scanning electron microscopy as: (1) adhesive between resin cement/dentin, (2) adhesive between resin cement/resin composite, (3) adhesive between resin composite/post or (4) mixed (involving 2 or more substrates). The results showed that after 24 hours, EDTA alone or associated with CHX significantly decreased the bond strength values when compared to control group. Sodium ascorbate alone or associated with NaOCl had the highest mean values of bond strength when compared to control group (P>0.05). The other groups showed values similar to control group but without statistical difference. After one year, only NaOCl groups, associated or not to EDTA, showed significant reduction of the bond strength values (P<0.05). Failure pattern was predominantly mixed, irrespective of storage period and irrigation protocol used. It was possible to conclude that sodium hypochlorite alone or in association with EDTA significantly jeopardizes the long-term bond. Sodium ascorbate alone or in association, was capable of improve and preserve the adhesion values after one year (AU)

• FAPESP's process: 11/10280-5 - In vitro evaluation of different irrigation protocols in the adhesive strength and longevity of anatomic posts cemented with a self-adhesive resin cement
• Grantee: Daniela Cristina Miyagaki
• Support Opportunities: Scholarships in Brazil - Doctorate