Smear Layer-Deproteinization: Improving the Adhesion of Self-Etch Adhesive Systems to Caries-Affected Dentin
- 27 Downloads
Purpose of review
This paper reviews a new method of dentin surface modification, smear layer-deproteinization for self-etch adhesive systems, particularly in relation to improving the adhesion to caries-affected dentin.
Remnants of smear debris, which forms hybridized smear layer with self-etch adhesives, can prevent monomer infiltration and interfere with the chemical interaction of adhesive monomers and the underlying dentin. The hybridized smear layer weakens the physical and chemical properties of the resin-dentin hybridized complex both immediately and over time. Smear layer-deproteinization with NaOCl and HOCl solutions can improve the quality of resin-dentin interface of self-etch adhesives through elimination of the hybridized smear layer, development of monomer infiltration, and enhancement of the chemical interaction of adhesive monomers with hydroxyapatite due to an increase in the mineral/organic ratio on the dentin surface. These positive effects are influenced by the types of oxidizing solution and their application time and also depend upon the adhesive materials used because compromising effects of residual oxidized-byproducts at the dentin surface on the polymerization behavior of the adhesives are different between the materials. However, applying antioxidant/reducing agents can eliminate this problem.
Smear layer-deproteinization is more effective for improving the bonding efficacy of self-etch adhesives to caries-affected dentin than normal dentin because caries-affected dentin produces a thicker organic-rich smear layer. Smear layer-deproteinization with HOCl solution, which has a rapid and broad-spectrum antimicrobial activity with less irritating and sensitizing properties, along with the subsequent application of antioxidant/reducing agents could enhance the longevity of composite restoration with self-etch adhesives.
KeywordsSelf-etch adhesive Smear layer Smear layer-deproteinization Oxidizing solution Antioxidant/reducing agent Caries-affected dentin
Compliance with Ethical Standards
Conflict of Interest
The authors declare that they have no conflict of interest.
Human and Animal Rights and Informed Consent
This article does not contain any studies with human or animal subjects performed by any of the authors.
Papers of particular interest, published recently, have been highlighted as: •• Of major importance
- 1.Ogata M, Harada N, Yamaguchi S, Nakajima M, Pereira PNR, Tagami J. Effects of different burs on dentin bond strengths of self-etching priming systems. Oper Dent. 2001;26:370–7.Google Scholar
- 8.•• Thanatvarakorn O, Nakajima M, Prasansuttiporn T, Ichinose S, Foxton RM, Tagami J. Effect of smear layer deproteinizing on rein-dentine interface with self-etch adhesive. J Dent. 2014;42:298–304. This article demonstrate that smear layer-deproteinizing with NaOCl and HOCl solution improves quality of the resin-dentin interface of a 2-step self-etch adhesive, eliminating hybridized smear layer, in which HOCl treatment was more effective than NaOCl treatment. CrossRefPubMedGoogle Scholar
- 9.•• Thanatvarakorn O, Prasansuttiporn T, Thitthaweerat S, Foxton RM, Ichinose S, Tagami J, et al. Smear layer deproteinizing improves on bonding of one-step self-etch adhesives to dentin. Dent Mater. 2018;34(3):434–41. This article clearly demonstrate that HOCl-smear layer-deproteinizing along with the subsequent application of a reducing agent improves dentin bonding of current 1-step self-etch adheisves. CrossRefPubMedGoogle Scholar
- 16.White C. Handbook of chlorination and alternative disinfectants. New York: John Wiley & Sons, Inc.; 1999.Google Scholar
- 19.•• Kunawarote S, Nakajima M, Shida K, Kitasako Y, Foxton RM, Tagami J. Effect of dentin pretreatment with mild acidic HOCl solution on microtensile bond strength and surface pH. J Dent. 2010;38(3):261–8. This article represents the first study to highlight HOCl solution as a pretreatment agent with dentin bonding of self-etch adhesives. CrossRefPubMedGoogle Scholar
- 21.•• Taniguchi G, Nakajima M, Hosaka K, Iwamoto N, Ikeda M, Foxton RM, et al. Improving the effect of NaOCl pretreatment on bonding to caries-affected dentin using self-etch adhesives. J Dent. 2009;37(10):769–75. This article brings the first insight concerning smear layer-deproteinizing for bonding of self-etch adhesives to caries-affected dentin. CrossRefPubMedGoogle Scholar
- 25.•• Prasansuttiporn T, Nakajima M, Kunawarote S, Foxton RM, Tagami J. Effect of reducing agents on bond strength to NaOCl-treated dentin. Dent Mater. 2011;27(3):229–34. This article provides important information related to reversal effect of antioxidant/reducing agents on compromised bonding to NaOCl-treated dentin. CrossRefPubMedGoogle Scholar
- 29.•• Nakajima M, Sano H, Burrow MF, Tagami J, Yoshiyama M, Ebisu S, et al. Tensile bond strength and SEM evaluation of caries-affected dentin using dentin adhesives. J Dent Res. 1995;74:1679–88. This article is a classical study about bonding to caries-affected dentin. It is the first study to reduce bond strength to caries-affected dentin with thick and poor hybrid layer formation. CrossRefPubMedGoogle Scholar