Influence of root dentin treatment on the push-out bond strength of fibre-reinforced posts

Abstract This study evaluates the influence of root dentin treatment with NaOCl alone and combined with EDTA, with and without ultrasound activation, on the push-out bond strength (BS) of fiber-reinforced posts in weakened roots, cemented with RelyX or Panavia. The root canals of 42 maxillary canines were instrumented with Reciproc and 2.5% NaOCl. In the coronal 12mm of all canals, experimental weakening of the roots was produced by reducing dentin thickness with 2.44mm diameter diamond burs. The roots were assigned to 3 groups (n = 14) according to root dentin treatment: 2.5% NaOCl; 2.5% NaOCl + 17% EDTA; and 2.5% NaOCl + 17% EDTA, with solutions agitated using passive ultrasonic irrigation. After cementation of the fiber-reinforced posts the roots were divided in thirds. The first slice of each third was used for the push-out BS test, the second slice for confocal laser scanning microscopy and dentin microhardness (Knoop) analysis. Data were analysed by a two-way ANOVA and Tukey test (a = 0.05). NaOCl + EDTA provided highest BS values than NaOCl (p