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Bonding of composite resin to contaminated human enamel and dentin
J M Powers1, W J Finger, J Xie
1Department of Basic Sciences-Oral Biomaterials, University of Texas-Houston Dental Branch 77030-3402, USA.
Purpose:
The purpose of this in vitro study was to evaluate the bond strengths of a bonding agent and composite resin system to human enamel and dentin treated with five contaminants (saliva, plasma, zinc oxide-eugenol cement, noneugenol zinc oxide cement, and handpiece lubricant) using air, moisture, and water as controls.
Materials And Methods:
A commercial bonding agent (Gluma 2000; Bayer AG, Dormagen, Germany) and its composite (Pekafill; Bayer AG) were applied to tooth structure under two conditions (contaminated and re-etched). Samples were debonded in tension after 24 hours using an inverted, truncated cone bond test.
Results:
Among the controls, the highest bond strengths were obtained to enamel (20 MPa) and dentin (12 MPa) with air drying. Contaminants lowered the bond strength by 20% to 100%. Re-etching without additional mechanical preparation resulted in bond strengths similar to the air control.
Conclusions:
Bond strength of Gluma 2000/Pekafill to tooth structure is sensitive to common forms of contamination but can be improved by re-etching after contamination occurs.