Effect of the time-point of acid etching on the persistence of sealer residues after using different dental cleaning protocols

Abstract

Endodontic sealer residues remaining within the pulp chamber dentin after root canal obturation and cleaning with various solvents may compromise the appearance and the durability of dental restorations. Acid etching is routinely performed prior to application of dentine adhesive systems, but is effect on residual sealer material and the optimal time-point for performing etching, are unknown. Here, we evaluated the effect of acid etching on the dentin surface when performed either immediately or 7 days after removal of the endodontic sealer with two solvents, i.e., 95% ethanol or xylol. Forty crowns fragments from bovine incisors were impregnated with sealer and divided into 4 groups (n = 10 each), according to the dentin cleaning protocol and to the acid etching time-point: G1, 95.0% ethanol and immediate acid etching; G2, xylol and immediate acid etching; G3, 95.0% ethanol and acid etching after 7 days; and G4, xylol and acid etching after 7 days. Scanning electron microscopy (SEM) images (2000 ×) were obtained from each specimen and the number of open dentinal tubules counted and compared. Another 40 fragments were similarly prepared, and SEM images were obtained (500 ×) to score and compare the persistence of sealer residues on the dentin. G4 showed the most open dentinal tubules and the least epoxy resin-based sealer residues on the dentin surface (p < 0.05). The least epoxy resin-based sealer residues was obtained when acid etching, using 37% phosphoric acid, was performed after 7 days after cleaning the dentin with xylol.

Effect of the calcium silicate‐based sealer removal protocols and time‐point of acid etching on the dentin adhesive interface

“…However, no differences were found in the ethanol groups, since ethanol is water‐miscible and the calcium silicate‐based sealer presents high solubility, regardless of the solvent polarity (Amoroso‐Silva, et al, ; Chávez‐Andrade, et al, ; Kuga, et al, ; Jordão‐Basso, Kuga, Bandéca, Duarte, & Guiotti, 2016). The results in the present study are differ from Jordão‐Basso, et al, () evaluation that observed a lower persistence of residues after xylol and acid etching carried out after 7 days. However, those authors evaluation was performed using epoxy resin‐based sealer.…”

“…However, no differences were found in the ethanol groups, since ethanol is water-miscible and the calcium silicate-based sealer presents high solubility, regardless of the solvent polarity (Amoroso-Silva, et al, 2014;Ch avez-Andrade, et al, 2013;Kuga, et al, 2012a; Jordão-Basso, Kuga, Band eca, Duarte, & Guiotti, 2016). The results in the present study are differ from Jordão-Basso, et al, (2016) evaluation that observed a lower persistence of residues after xylol and Residues from the calcium silicate-based sealer negatively affected the extent of the hybrid layer formation in dentin. Ethanol solution and acid etching carried out after 7 days was the least affecting protocol to the hybrid layer formation.…”

“…Acid etching favors dentin surface cleansing and provides hybrid layer formation in the underlying dentin (Rosa, et al, ; Jordão‐Basso, Kuga, Bandéca, Duarte, & Guiotti, ). However, the best moment for acid etching and adhesive system application is still uncertain, since their immediate application after the dentin cleansing favors epoxy‐based sealer residues persistence Jordão‐Basso, Kuga, Bandéca, Duarte, & Guiotti (). The ideal cleaning substance to remove residues from calcium silicate‐based sealer and the best acid etching moment are still unclear.…”

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

“…[ 1 2 ] Ethanol, xylol, amyl acetate, or eucalyptol have already been recommended for surface cleansing; however, their effectiveness is still questionable. [ 3 4 5 6 ] It favors the sealer residues persistence, which may cause discoloration of dental crown and/or negatively affect the adhesive interface between dentin and adhesive system, compromising the cosmetic restorations longevity. [ 1 2 3 4 5 6 7 8 ]…”

“…Ethanol is the most commonly used substance in cleaning protocol of dentin impregnated with endodontic sealer. [ 6 8 ] It is used alone or associated with diamond bur debridement in the cleansing treatment of dentin surface impregnated with zinc oxide-eugenol-based sealer (Endomethasone), reverting the bond strength of self-etching adhesive system to dentin. [ 8 ] On the other hand, ethanol is ineffective in cleansing dentin with epoxy-based sealer residue.…”