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

Abstract

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 < 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.

Can intra-radicular cleaning protocols increase the retention of fiberglass posts? A systematic review

“…A n i n it i a l e le c t r on ic s e a r c h ide nt i f ie d 473 studies (Figure 1), and the hand searching process identified 2 studies 8,23 (total of 475 studies). The initial screening of the titles and abstracts resulted in 20 full-text papers that were read in full.…”

“…The characteristics of the 9 included studies are summarized in Table 1. 8,17,19,23,24,25,26,27,28 Eleven studies that did not meet the inclusion criteria ( Figure 1) To investigate the effect of QMix irrigant compared with several other irrigating solutions on the bond strength of glass fibre posts to root dentine and on smear layer removal after post space preparation.…”

“…The retention between root dentin and resin cement is a critical point for luting FGPs, since interference in the resin-dentin diffusion zone affects the longevity of the FGPs. 23,40,41 Although several studies have evaluated the effect of post surface treatments and cementation strategies on the retention of FGPs, the presence of the smear layer and debris along the post-space canal walls can also affect the optimal dentin adhesion. 8 The role of cleaning methods after post-space supports clinicians in terms of evidence-based decision making.…”

“…51 Considering these criteria, only nine studies were included, of which five studies showed better results for the combination of NaOCl/EDTA, regardless of the sequence of the use. 17,23,25,27,28 The increased FGP bond strength after the combination of NaOCl/EDTA solutions 17,23,25,27 may be attributed to the ability of the solutions to remove the smear layer, thus improving cement contact and penetration into dentinal tubules. 25 Recently, the use of irrigation activated by ultrasonic, lasers, and negative apical pressure (Endovac) has been discussed.…”

“…Seven studies used the association of NaOCl/EDTA in some of their experimental groups. 8,17,23,24,25,26,27,28 Chlorhexidine appeared in 3 studies, 18,25,26 although in one of these studies, there was also the presence of chlorhexidine in the composition of a commercial solution called Qmix. 26 Other solutions that were also tested included NaOCl and EDTA used individually, with some variations of time and concentration, 8,16,18,26,27 of which the most used concentrations were 5.25% NaOCl and 17% EDTA both for a maximum of 1 minute.…”