Effect of cleaning protocols on bond strength of etch-and-rinse adhesive system to dentin

Abstract

Aim:This study aimed to evaluate the cleaning protocol of dentin impregnated with epoxy resin-based sealer (AH Plus) and the effects on the adhesive interface using 95% ethanol (E) or formamide solution (F) associated with microabrasion with glass microparticles (M).Methodology:Forty dentin specimens were impregnated with sealer (AH Plus). Specimens were cleansed according to the following protocols (n = 10): G1 (E); G2 (F); G3 (E = M); and G4 (F = M). No treatment was performed in G5 (control). Specimens were subjected to standard error of the mean to evaluate the residues persistence (×500) and open dentinal tubules counting (×2000). Another fifty specimens were subjected to similar procedures and cleaning protocols. Seven days later, composite-resin-made specimens were performed on dentin using etch-and-rinse adhesive system, then submitted to microshear test.Results:G2 and G4 showed higher residues' persistence and lower incidence of open dentinal tubules than G1 and G3 (P < 0.05). No difference was found between G1 and G3 or G2 and G4 (P > 0.05). Adhesive system bond strength was similar in all groups (P > 0.05).Conclusions:Microabrasion negatively affected the epoxy resin-based sealer residues' removal protocols' action; all groups presented residues on the dentin surface. However, 7 days later, the protocols did not affect the bond strength of adhesive system to sealer-impregnated dentin.

Microtensile bond strength to sealer-contaminated dentin after using different cleaning protocols

“…Scanning electron microscopy (SEM) is often used to observe sealer residues and requires specimen processing, such as spraying gold and a vacuum environment. 10 , 11 , 12 , 13 In the present study, a real-time noninvasive SS-OCT imaging technique was used to evaluate trapped sealer remnants in the dentin-adhesive interface. 24 OCT technology has been used in several clinical applications, such as monitoring the internal adaptation of resin composite restoration and cariogenic demineralization and detecting tooth cracks.…”

“…During the last two decades, there have been 10 published in vitro studies on sealer removal, with different cleaning methods proposed. 6 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 Dry cotton pellets and organic solvents were mostly studied, followed by mechanical drill refinement, air polishing, microabrasion. It has been found that after cleaning using dry cotton pellets, the bond strength decreased to 69%–88% to that of uncontaminated controls.…”

“… 6 , 12 In practice, ethanol is a routinely used solvent for surface cleaning due to its easy accessibility, but its efficiency is unfavorable. 6 , 10 , 11 , 12 , 13 As for acetone, it is a bipolar solvent that can dissolve both polar and nonpolar compounds. The epoxy-resin based AH Plus sealer, which is composed of apolar substances, is probably partially miscible with acetone, enabling it to be dissolved by acetone according to the “like dissolves like” concept.…”

“…The most common recommended method to clean sealer residues on intracoronary dentin is to use organic solvents, such as ethanol, formamide and acetone. 6 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 Researchers have been pursuing an ideal solvent that is safe and effective for removing sealer remnants and exerts minimal negative effects on bonding procedures. However, to date, no solvent has satisfied all the expectations.…”

Hybrid layer formation and bond strength to dentin impregnated with endodontic sealer after cleaning protocols

“…In addition, acid etching was reported as a promising strategy to remove the smear layer of root dentin,[ 24 ] since it provides open dentinal tubules and consequently better adhesion between the adhesive system and the dentin. [ 25 ]…”