Influência de materiais obturadores e agentes de limpeza na resistência da união e interface adesiva de pinos de fibra de vidro à dentina intrarradicular / Influence of filling materials and cleaning agents on bond strength and adhesion interface of glass fiber post to radicular dentin

AUTOR(ES)
FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

28/02/2012

RESUMO

The aim of this in vitro study was to evaluate the post-cement-dentin adhesive interface quality and the effect of different filling materials and cleaning agents on the bond strength of glass fiber posts to primary root dentin. This study included 156 roots of bovine primary teeth which were endodontically treated and assigned to four groups (39 teeth each group) according to filling materials: 1 - control (no material); 2 - Calen® paste + zinc oxide (ZO); 3 - Vitapex® paste; and 4 - Calcipex II® paste. After seven days, the filling materials were removed and the roots for each material subdivided into 3 groups (13 teeth) according to cleaning agents: A - No cleaning (control); B - 70% ethanol; and C - Tergenform®. Glass fiber posts were luted using dual polymerized resin cement (RelyXMR ARC) after 35% acid etching, rinsing and application of the adhesive system (Adper Single BondTM 2). The specimens were stored for 7 days, sectioned and prepared for push-out bond strength test (n=10) and interface analysis by silver nitrate leakage (n=3). A push-out test was performed using a universal test machine (EMIC) at a crosshead speed of 0.5 mm/min. Data obtained in Kgf were converted into MPa and submitted to two-way ANOVA (filling materials x cleaning agents) and Tukey tests (p<0.05). After the push-out test, representative samples of the groups were submitted to scanning electron microscopy (SEM) to illustrate the failure modes. The adhesive interface between dentin/cement and cement/post were also analyzed by SEM. The leakage (expressed in percentage) was measured by a single examiner previously calibrated (intra-examiner coincidence level = 98%) using a silver nitrate solution. Data obtained for leakage were submitted to the Kruskal-Wallis test (p<0.05) and descriptive analysis. Interaction was observed between filling materials and cleaning agents, concerning bond strength values (p=0.0043). Calen® paste+ZO with 70% ethanol showed the highest values, significantly different from the groups using no cleaning agents. Vitapex® and Calcipex® showed no significant difference between cleaning agents. The lowest bond strength values were found for the control with Tergenform®. No statistical difference was observed between groups concerning silver leakage (20.63% to 56.62%) in the adhesive interface between cement and dentin. In conclusion, filling materials and cleaning agents influenced the bond strength, but not the adhesive interface between intracanal posts and root dentin; as a cleaning agent, 70% ethanol responded better to Calen® paste+ZO; cleaning agents are not required for Vitapex® and Calcipex®; all groups showed leakage in the adhesion interface between cement resin/dentin root, regardless of the filling materials and cleaning agents studied.

ASSUNTO(S)

obturação do canal radicular pinos dentarios resistencia ao cisalhamento infiltração dentária microscopia eletrônica de varredura dental pins shear strength dental leakage microscopy electron scanning root canal obturation

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