Self-etching adhesives: review of adhesion to tooth structure part I.
Self-etching adhesives with their easy handling technique and promise of no post-op sensitivity are increasingly popular among dental practitioners. As with any new bonding material, in vitro and in vivo investigations are required to assess the clinical efficacy of these systems. The current literature was reviewed to provide information about these systems in terms of: etching of and adhesion to prepared and unprepared enamel, primary enamel and sclerotic or caries-affected dentine. Published abstracts and research papers on laboratory studies, as well as reviews available in the dental literature. Although the etching aggressiveness of self-etching systems can be used to predict the depth of demineralisation of tooth structure and the ultra-structure and thickness of the hybrid layer, it cannot be correlated to the bond strengths obtained on enamel and dentine. A certain mild two-step self-etching system, for example, consistently provides similar or higher bond strengths than more aggressive self-etching systems in laboratory studies. Where either intact enamel or sclerotic or caries-affected dentine is involved, self-etching systems generally provide lower bond strengths than total-etch systems; therefore coarsening of tooth structure, extra etching time or an extra application of the primer is recommended.