Technique: Adhesion dentistry 101
What you need to know about adhesion dentistry.
In 1955, Michael Buonocore, DDS, documented the use of phosphoric acid to improve adhesion of resin to dental enamel1. Since Dr. Buonocore’s observation, adhesion dentistry has played an important role in the evolution of dentistry. Bonding procedures are performed by dentists every day, ranging from bonding orthodontic brackets to delivering stunning porcelain veneers. Because adhesion dentistry is such an indispensable part of the day to day practice of dentistry, a review of its principles will help to refresh the minds and influence the hands of clinicians practicing at every level of experience.
What is Adhesion?
In dentistry, adhesion is the chemical and micromechanical union of an adhesive system to enamel, dentin, and a restorative material. Put another way, adhesion is the bond between a tooth and an adhesive, the bond between an adhesive and a resin, and in the case of indirect restorations, the bond between a resin and a restoration. Practical applications of this process include superior retention of restorations, improved performance and durability of certain materials, the ability to affect the color properties under an indirect restoration and low solubility. Clinically, these benefits are tempered by heightened technique sensitivity, increased moisture control and isolation requirements, and shrinkage of resin based materials.
Optimal Adhesion to Enamel
Due to its low water content and mineralized crystalline structure, adhesion to etched enamel is very strong and predictable. It is advised that phosphoric acid with a concentration of 32 to 37 percent be applied for 15 seconds on cut enamel, and 30 seconds on uncut enamel.2 Appropriate moisture control measures will prevent enzymes and organic molecules within blood, saliva and crevicular fluid from contaminating the etched enamel. These may include use of various suction devices, a mouth prop, cotton drying aids, retraction cord or a rubber dam. Isolation techniques may include using plastic or metal matrices, wedges and rubber dam isolation.
Up next: See a step-by-step enamel adhesion case