Effect of Decontamination Treatments on Micro-Shear Bond Strength between Blood–Saliva-Contaminated Post-Etched Dentin Substrate and Composite Resin

Abstract

Blood–saliva contamination negatively affects the bonding potential of adhesive agents. The study aimed to assess the effect of various cleaning protocols on micro-shear bond strength (μSBS) between blood–saliva-contaminated post-etched dentin and composite resin in total-etch and self-etch adhesives. The cleaning methods tested were water rinsing, 37.5% phosphoric acid (H3PO4) re-etching, 6% sodium hypochlorite (NaoCl), 2% chlorhexidine gluconate (CXG), isopropyl alcohol (IPA), and pumice. Nono-hybrid composite cylinders with a 3-mm diameter and 2-mm height were directly cured over the dentin substrate, stored for 24 h, and subjected to 12,000 thermocycles. The shear force was exerted with a 200-μm knife-edged chisel-shaped head from a universal testing machine. The type of failure was assessed with stereomicroscope magnified images. The obtained data were evaluated by Kruskal–Wallis and Mann–Whitney U post-hoc tests. Water-rinsed contaminated dentin surfaces showed substantially reduced μSBS in the total etch from 25.93 to 20.29 Mpa and the corresponding values for the one-step self-etch adhesive were 10.10 to 8.8. Re-etching with 37.5% H3Po4 resulted in a recovery of bonding potential in both total-etch (24.58 Mpa) and self-etch adhesive (9.23 Mpa). Alternately, NaoCl and pumice cleaning showed promising results for the total-etch (23.51 Mpa) and self-etch (7.79 Mpa).

Effect of Saliva/Blood Contamination on Enamel Bond Strength

“…The increase in bond strength may be related to the ability of the adhesives to penetrate micro-spaces created by acid etching, i.e., the high diffusion coefficient of monomers. 16 Furthermore, the composition of adhesives seems to be particularly suitable for the bonding to contaminated enamel. Due to the hydrophilic nature of adhesives, they can remove saliva/blood (moisture) from the enamel surface, which allows infiltration of the hydrophilic monomer in the enamel pores.…”

“…8 Surprisingly, little attention has been paid by researchers to contamination with blood, so there is considerable heterogeneity regarding the type of blood used in contamination studies. While some have used drawn recently blood, 16 others use anticoagulated blood 17 or plasma, 14 while others do not specify the type of blood used in their publications. 18 Based on these clinical difficulties, studies have been developed and they have found that bond strength between the resin sealant and contaminated surface is drastically decreased, 19 which results in complete or partial displacement of sealant in the short term.…”

Comparative evaluation of different surface treatments of the salivary contaminated dentin on the shear bond strength of self-etch adhesives: An in vitro study

“…Various studies done to date have reported variable results. Even few studies[ 4 5 ] have reported that the saliva contamination of dentin had no adverse effect on the bonding efficiency of one-bottle adhesive systems while others have shown that the saliva contamination of the dentin surface produced a significant decrease in the bond strength[ 6 7 8 9 10 11 ]…”

“…The results are in accordance with many other studies that showed that contamination of the bonded surface after curing of the self-etch adhesive results in lower bond strength. [ 6 7 9 10 11 13 ]…”

“…The results are in agreement with studies done by Furuse et al . [ 15 ] and Haralur et al .,[ 6 ] who reported that reetching of a cured contaminated adhesive, eliminated the contaminant residue and removed the adhesive coating. [ 16 ]…”