Effect of acid etching and aging on bond strength of a universal adhesive on dental enamel

The best bonding to enamel is achieved by selective etching of enamel margins [SE] (with phosphoric acid gel) prior the application of self-etch one-step multi-mode universal adhesive [SEUA].1‒11 When using the self-etch approach, the adhesion depends on the material formulation. Particularly for mild SEUA (e.g. Scotchbond Universal Adhesive (SBU)), systematic reviews showed a less favorable adhesion to enamel.12,13 In this line, despite the relevance to predict clinical outcomes,14‒16 few in vitro studies about SBU have addressed microtensile bond strength [μTBS] to enamel under the influence of SE.2,5, 6 Besides, the effect of storage water thermocycling time should be also highlighted. Reduced μTBS values were observed when human enamel blocks underwent storage for 24-hour,2 maybe a short time for accurate measures failures. Longer time (12-month) studies (which should be encouraged in order to predict the clinical effectiveness of adhesives),17 do not definitively aver that question.6,11