Clinical Research Associates
Adhesive Bond Strength Pilot Study
Some lights do not cure some adhesives. A pilot study was conducted to investigate bond strength values for these problematic light / resin combinations.
Click here for test methods
Summary of chart: Highest bond strength was obtained using Optilux 500 halogen light. Unpolymerized adhesive & low bond strengths resulted from short cure times with AccuCure 3000 argon laser & Apollo 95 E plasma arc light with 470 tip. Increasing cure time to 60 seconds, with the 470 tip, resulted is some polymerization & higher bond strength. Using short cure time, with the new 430 tip, resulted in cured adhesive & improved bond strength.
Summary of chart: Highest bond strength was obtained using Optilux 500 halogen light. When short cure times were used with the AccuCure 3000 argon laser & Apollo 95 E plasma arc light (470 tip), adhesive did not polymerize adn bond strengths were low, as shown in the chart. Use of new 430 tip did not significantly improve bond strength, although adhesive did polymerize. Cure times of 0, 2, & 20 seconds with the Virtuoso plasma arc light resulted in statistically similar bond strengths which were all lower than the halogen light value.
Summary of chart: Cure times of 0 & 20 seconds with the Optilux 501 halogen light progressed the adhesive from liquid to firm; yet bond strengths were statistically similar.
The data from this pilot study suggest the following:
1. Adhesive that does not cure, either when placed, or when restorative resin is cured over it, results in lower bond strengths.
2. Extending the cure time may produce better bond strengths for some light / resin combinations. However, for some light / resin combinations, high bond strengths may not be possible regardless of cure time.
3. The effects of intensity, wavelength of light, & cure time on adhesives needs further investigation, especially with rapid cure argon lasers & plasma arc lights.