The bond between restorative resin and enamel may be likened to a chain with a series of links. The potentially weakest link is the interface between the resin and the tissue. This link is established by the clinician and is considered to be technique sensitive. An understanding of the steps in clinical method provide a rationale and an aim for each step. A thorough dental prophylaxis to remove deposits, including calculus from enamel, is important in allowing the acidic conditioning agent, namely phosphoric acid, to exert its optimal effect. Conditioning of the enamel raises its surface energy, creates increased surface area and enhances tissue porosity in the outermost enamel. These conditions are achieved through careful isolation of the teeth and thorough washing to remove the acid and reaction products. A dry field is also of paramount importance in obtaining the micromechanical retention of the resin within the enhanced tissue micropores. The polymerized resin within the tissue serves to retain the bulk of resin located upon the enamel surface. The method is a clinically conservative, non-traumatic, biocompatible means by which resins, polymerizable under oral conditions, can be bonded durably to enamel.