Choosing an Adhesive That Really “Sticks”
Adhesive dentistry has permeated into all aspects of direct and indirect restorative dentistry. This has marked a huge advance in dentistry from preservation of tooth structure with minimally invasive dentistry, to the ability to save a tooth with little remaining tooth structure.
Improvements have been made from one generation of dental adhesive to the next. The fourth generation of adhesives is often referred to as the “gold standard” due to its strong enamel and dentin bond strengths and versatility; however, its drawback was that it consisted of a multi-bottle kit with a thick instruction manual. Every generation after that has aimed at reducing the number of components as well as the time taken to place the adhesive. With the exception of the fifth generation adhesive, all other generations achieved an easier-to-use product, but often compromised the procedure with lower bond strengths, degradation of the bond over time, and less versatility.
It should be noted that the application of the dental adhesive comes after the acidic treatment of the smear layer. The smear layer is produced by the accumulation of tooth and bacterial debris caused by the preparation of the tooth. This layer can cover much of the dentin surface, collagen fibers, and dentinal tubules, all elements critical to a successful, long-lasting bond. Total-etch techniques using phosphoric acid removes the smear layer, exposing the dentin, collagen fibers, and dentinal tubules to receive the adhesive. Self-etch techniques vary greatly in their ability to remove any of the smear layer and their lack of effectiveness on uncut enamel required that you acid etch enamel before proceeding with the self-etch procedure.