Limited Etching Time Increases Self-adhesive Resin Cement Adhesion to Enamel

Area of Science:

• Dental Materials Science
• Adhesive Dentistry
• Biomaterials Engineering

Background:

• Self-adhesive resin cements (RCs) are widely used in dental restorations.
• Enamel surface treatment is crucial for achieving optimal bond strength.
• The effect of etching time on RCs with different compositions requires further investigation.

Purpose of the Study:

• To assess how varying enamel etching durations influence the bond strength of two self-adhesive resin cements.
• To determine the impact of thermocycling on the bond strength of these cements under different etching conditions.

Main Methods:

• Bovine enamel blocks were treated with two self-adhesive resin cements (MaxCem Elite, RelyX U200).
• Enamel was etched for 0, 5, 10, or 20 seconds, followed by cement application.
• Specimens were stored in distilled water or subjected to thermocycling (5000 cycles) before shear bond strength (SBS) testing.

Main Results:

• Enamel etching generally increased SBS for both resin cements, with 5 and 10 seconds showing the most significant improvement.
• Thermocycling adversely affected the SBS of non-etched (control) groups.
• Resin tag formation was observed to be time-dependent, with no tags present in the control groups.

Conclusions:

• A 10-second enamel etching time appears optimal for enhancing enamel-resin bond strength.
• Acid etching is essential for maintaining bond strength, particularly when specimens are subjected to thermocycling.