Many of these restorations can be replaced conservatively with direct composite. Unfortunately, however, many of the placement and accompanying adhesive protocols required for predictability can be time-consuming and technique sensitive. That’s why it’s important to understand the historical development of dental equipment when considering today’s etching and adhesive protocol options to determine which will serve you—and your patients—best.
In the total-etch (etch-and-rinse) technique, both enamel and dentin are etched with phosphoric acid to remove the smear layer and condition the preparation prior to bonding (the enamel is etched longer than the dentin). The etchant and smear layer are then rinsed off with water and gently air-dried. Because dentin should remain moist and glossy in appearance, care must be taken not to overdry the dentin. This prevents collagen fibrils from collapsing, which would create a less permeable surface for hydrophilic monomers in the adhesive, as well as a weak interface that could lead to a poor bond and postoperative sensitivity. Although total-etch adhesives and their associated multistep techniques are well established and clinically proven, they are often considered to be technique sensitive.
Manufacturers have helped to streamline adhesive protocols by introducing universal adhesives that promote high bond strength to enamel and dentin and that can be used on both dry and moist dentin. Because they are designed to work with or without phosphoric acid, dental micro motor, universal adhesives (e.g., Adhese Universal from Ivoclar Vivadent) are suitable for all etching techniques without the risk of overetching the dentin.
Presenting a case involving multiple failing side-by-side amalgam posterior restorations, Michael R. Sesemann, DDS, FAACD, explains how selective etching, universal adhesive, and bulk-fill composite can be combined for efficient and predictable posterior quadrant restorations.