Self-etching adhesives

El Araby, A.M. and Y.F. TaHc, The effect of thermocycling on the adhesion of self-etching adhesives on dental enamel and dentin. The Journal of Contemporary Dental Practice, 2007.8(2) 1-11. 

As formulated, liquid self-etch adhesives consist of aqueous solutions of functional monomers, cross-linkers and additives such as fillers and free radical initiators [56,57]. Water has to be present to allow the acid to ionize and thus be capable of carrying out its etching function [56], The presence of water in the formulation means that self-etch adhesives less susceptible to variations in the moisture content of the substrate. 

Self-etch adhesives vary in their acidity [58]. Some are very acidic, with a pH around 1 and interact quite strongly with the freshly cut tooth surface, penetrating several microns into the depth of either the dentine or the enamel. Some are considered only moderately strong, and these have a pH between 1 and 2. This allows them to penetrate to a depth of only about 1-2 pm [15]. Some are mild, with a pH of about 2, which permits penetration to a depth of about 1 pm only. Lastly, there are the ultra-mild adhesives, which have a pH of about 2.5. These penetrate the tooth surface to only a slight extent, typically in the nano-metre range [59]. 

The essential mechanism of action of self-etch adhesives is that they simultaneously etch and prime the freshly cut tooth surface, and in doing so, incorporate the components of the smear layer [58,60]. Because of the presence of the smear layer, and also because of smear plugs blocking the dentinal tubules, self-etch adhesives have been claimed to provoke less post-operative sensitivity in patients than the etch-and-rinse approach [61,62]. However, this has not been confirmed by scientific studies [63,64], but rather any reduction in patient discomfort has been attributed to operator technique [15]. 

M. Peirmans, J. De Mimck, K.L. Van Landuyt, A. Poitevin, P. Lamhrechts, B. Van Meerbeek, Eight-year clinical evaluation of a 2-step self-etch adhesive with and without selective enamel etching. Dent. Mater. 26 (2010) 1176-1184. 

J. Perdigao, S. Geraldeh, J.S. Hodges, Total etch versus self-etch adhesive effect on postoperative sensitivity, J. Am. Dent. Assoc. 134 (2003) 1621-1629. 

C. de Sonza Costa, A. Lopes do Nascimento, H. Teixeira, U. Fontana, Response of human pulps capped with a self-etching adhesive system. Dent. Mater. 17 (2001) 230-240. 

Y. Kitasako, S. Shibata, J. Tagami, Migration and particle clearance from hard-setting Ca(OH)j and self-etching adhesive resin following direct pulp capping. Am. J. Dent. 19 (2006) 370-375. 

Bayle, M.A., Gregoire, G., and Sharrock, P. (2007) The role of acry-lophosphonic acid monomers in the formation of hybrid layers based on self-etch adhesives. / Dent, 35 (4), 302-308,... 

Faria-e-Silva, A.L. et at. (2010) Degree of conversion of etch-and-rinse and self-etch adhesives light-cured using QTH or LED. Oper. Dent, 35 (6), 649-654. 

McLean JW, Nicholson JW, Wilson AD (1994) Proposed nomenclature for glass-ionomer cements and related materials. Quintessence Int 25 587 Miller MB (2002) Self-etching adhesives solving the sensitivity conundrum. Pract Proced Aesthet Dent 14 406... 

Tay FR, King NM, Chan KM, Pashley DH. How can nanoleakage occur in self-etching adhesive systems that demineralize and infiltrate simultaneously J Adhes Dent. 2002 4(4) 255—269. 

Salz U, Zimmermann J, Zeuner F, Moszner N. Hydrolytic stability of self-etching adhesive systems. J Adhes Dent. 2005 7(2) 107—116. 

Chemical composition of adhesives should be (is) selectively defined [99] such that the above mechanistic requirements may successfully be fulfilled. Even though dental adhesives can be classified into two main groups, i.e., etch and rinse (E Rs) and self-etch adhesives (SEAs) (Figure 10.4),... 

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