Effect of NaOCl and EDTA as Post Space Cleansing Solutions on the Bond Strength of Resin Cements to Root Canal Dentin (An in vitro Study)

Raghad Al-Askary

doi:10.33899/rden.2020.165177

Abstract

Aims: To evaluate the regional bond strength of four resin-based luting cements to post space dentin after irrigating with different irrigant solutions regimens. Materials and Methods: Eighty extracted human lower premolars were decoronated, instrumented, and obturated. Post space was prepared in each root, then randomly divided into four groups (n=20) according to the final irrigation regimen for the post space, Gp.1: distilled water (DW) control; Gp.2: 5.25% NaOCl+DW; Gp.3: 17%EDTA+DW; Gp.4: 5.25%NaOCl+17% EDTA+DW. Each group was further subdivided into four subgroups (n=5) according to the luting cements, Gp.(1,2,3,4)A (Vivaglass®Liner); Gp.(1,2,3,4)B (PermaCem®-Dual); Gp.(1,2,3,4)C (Variolink II); Gp.(1,2,3,4) D (LuxaCore®Z-Dual), then each post-space was sectioned horizontally into three slices. A push-out test was performed to measure regional bond strengths and the fracture modes was evaluated using a stereomicroscope. Results: The use of 5.25% NaOCl+17% EDTA+DW result in higher bond strength than other treatments. While the control group gives the lowest. (LuxaCore®Z-Dual) showed the highest bond strength than other resin cements. (Vivaglass®Liner) gives the lowest bond strength. The regional bond strengths decreased significantly toward the apical third. The failure mode recorded was mostly adhesive in nature except for groups (3D,4D) showed some mixed failure at the coronal third. Conclusions: NaOCl+ EDTA flush had a profound effect on resin bond strength to radicular dentin. (LuxaCore®Z-Dual) composite core buildup material exhibited the higher regional bond strength to radicular dentin. The regional bond strength decreased from coronal to apical direction.

Highlights

Sodium hypochlorite (NaOCl) and ethylenediaminetetraacetic acid (EDTA) are substances usually used during the endodontic treatments.(6,10) NaOCl used for their antibacterial and tissue-dissolving properties for the organic portion of smear layer.(4,9,13) EDTA is a chelating agent that removes calcium ions to produce dentin demineralization.(8,9,12)
Adhesion to radicular dentin may be affected by many factors like the presence and thickness of endodontic smear layer, the difficulty of the curing light to reach many parts of root canal dentin, the gaining of direct vision to the root canal, moisture control and adhesive application, and the effect of different viscosity of the luting cements. (1-4,7,14)
Studies(3,6,7,10,11,16) investigating smear layer removal have shown that the most effective mean of smear layer removal involve a combination of EDTA and NaOCl to remove both inorganic and organic components in which it is total removal improves the adaptation of filling materials to the root canal

Summary

Introduction

The creation of a strong and stable bond between luting cements and radicular dentin will contribute to the clinical performance of luted post.(1,2) Resin cements have been selected for their advantageous mechanical and adhesive properties compared with conventional luting cements for post cementation.(3,4,5)In addition to the traditional smear layer produced by manually or rotary instrumentation of the root canal, the subsequent preparation of the post space using post drills resulted in an additional and www.rafidaindentj.netAl-Askary RA even thicker smear layer composed of debris and sealer/gutta-percha remnants that has adverse effect on the adhesion to the radicular dentin.(5-7) achieving clean dentinal surfaces after mechanical post space preparation seems to be a critical step for optimal post retention when resin cement is used.(8-11)Dentin surface treatment with different irrigation regimens may cause alteration in the chemical and structural composition of human dentin, thereby changing its permeability and solubility characteristics and affecting the adhesion of materials to dentin surface.(1,2,5,7,12)Sodium hypochlorite (NaOCl) and ethylenediaminetetraacetic acid (EDTA) are substances usually used during the endodontic treatments.(6,10) NaOCl used for their antibacterial and tissue-dissolving properties for the organic portion of smear layer.(4,9,13) EDTA is a chelating agent that removes calcium ions to produce dentin demineralization.(8,9,12)Adhesion to radicular dentin may be affected by many factors like the presence and thickness of endodontic smear layer, the difficulty of the curing light to reach many parts of root canal dentin, the gaining of direct vision to the root canal, moisture control and adhesive application, and the effect of different viscosity of the luting cements. (1-4,7,14)Self- adhesive cements introduced in 2002 as a new subgroup of resin cements, these materials designed with the purpose of overcoming some limits of both conventional and resin cements. Adhesion to radicular dentin may be affected by many factors like the presence and thickness of endodontic smear layer, the difficulty of the curing light to reach many parts of root canal dentin, the gaining of direct vision to the root canal, moisture control and adhesive application, and the effect of different viscosity of the luting cements. Dual-cured resin composite for core build-up have been used to cement prefabricated posts, studies showed that it is a luting materials with improved mechanical properties better than dual-cued resin cements.(14,15). The purpose of this in vitro study was to evaluate the regional bond strength of four resin-based cements to post-space dentin after irrigation with sodium hypochlorite and ethylenediaminetetraacetic acid Dual-cure cements were developed to conciliate the favorable characteristics of self-cured and light-cured cements by extended the working time, and capable of reaching a high degree of conversion in either the presence or absence of light.(1,3)

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Discussion

Conclusion