IADR/DIV/CED/2011 location:Theoretical Building of the Semmelweis University date:01-09-2011
Today, both etch-and-rinse and self-etch procedures can be used to bond composite to enamel and dentin. Ideally, durable bonding can be achieved following a three-step procedure by first selectively etching enamel with phosphoric acid, followed by application of successively a ‘mild' self-etch primer to the etched enamel and (unetched) dentin, and finally a separate solvent-poor adhesive resin. Indeed, enamel requires phosphoric acid to expose a micro-retentive etch pattern, in which resin is known to stably interlock. Phosphoric acid might however be too aggressive for dentin, as it removes the natural hydroxyapatite protection and exposes dentinal collagen up to several micrometers deep. Bonding should be obtained by diffusion of resin in an attempt to envelop the exposed collagen, which hardly can be achieved completely. The alternative mild self-etch approach keeps collagen protected by hydroxyapatite. Specific functional monomers have been shown to effectively interact chemically with hydroxyapatite to the direct benefit of bond durability. As several bonding approaches can thus today be used, a ‘modular' adhesive was recently developed to be applied following either a full ‘etch-and-rinse' or full ‘self-etch' approach, or a combined ‘etch-and-rinse' (selectively at enamel) and ‘self-etch' approach (at both pre-etched enamel and dentin). The purpose of this presentation is to present how this modular adhesive interacts with enamel and dentin following the different approaches, as well as what bonding effectiveness can be achieved accordingly.