IN-VITRO BOND STRENGTH OF 2 ADHESIVES TO ENAMEL AND DENTIN UNDER NORMAL AND CONTAMINATED CONDITIONS

In vitro bond strengths of human enamel and dentin treated with five c ontaminants were measured with air, water and damp conditions as contr ols. Two commercial bonding agents (a lower-viscosity, solvent-contain ing type, AB, and a higher-viscosity, hydrophilic monomer type, SB) an d their composites were applied to tooth structure under two condition s (contaminated and re-etched). Samples were debonded in tension after 24 h using an inverted, truncated cone test. Among the controls, the highest bond strengths were obtained with damp conditions for AB (24 M Pa) and damp conditions or air for SB (22 MPa) with small differences between enamel and dentin. Most contaminants lowered the bond strength . Re-etching without additional mechanical preparation resulted in bon d strengths similar to controls. Bond strengths to tooth structure wit h the bonding agents tested may be less sensitive to common forms of c ontamination than typically assumed.