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

• Main Authors: Altair Soares MOURA (Author), Rodrigo Dantas PEREIRA (Author), Fuad Jacob Abi RACHED JUNIOR (Author), Bruno Monguilhott CROZETA (Author), Jardel Francisco MAZZI-CHAVES (Author), Luis Eduardo SOUZA-FLAMINI (Author), Antonio Miranda CRUZ FILHO (Author)
• Format: Book
• Published: Sociedade Brasileira de Pesquisa Odontológica, 2017-04-01T00:00:00Z.
• Subjects: article
• Online Access: Connect to this object online.
• Notes: 1807-3107; 10.1590/1807-3107bor-2017.vol31.0029
• Keywords: Microscopy; Confocal; Dental Bonding; Endodontics; Dentistry; RK1-715
• Source: Brazilian Oral Research, Vol 31, Iss 0 (2017)

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 < 0.0001). Specimens cemented with Panavia presented significantly higher BS than those with RelyX in the three root thirds (p < 0.0001). The highest BS values occurred in the cervical third (p < 0.001). Ultrasound-activated NaOCl + EDTA promoted the greatest reduction in dentin microhardness, followed by NaOCl/EDTA and NaOCl. Ultrasonic activation of NaOCl and EDTA reduced root dentin microhardness, but did not improve the push-out BS of resin-based cements. Panavia presented higher BS than RelyX. RelyX was not influenced by the root dentin treatment protocols.