A Novel Enamel and Dentin Etching Protocol Using α-hydroxy Glycolic Acid: Surface Property, Etching Pattern, and Bond...

Area of Science:

• Dental Materials Science
• Biomaterials Engineering
• Surface Chemistry

Background:

• Surface pretreatment is crucial for effective dental restorations.
• Traditional etchants like phosphoric acid (PA) can be aggressive.
• Novel etchants are sought to optimize adhesion and minimize tissue damage.

Purpose of the Study:

• To evaluate glycolic acid (GA) as a surface pretreatment for dental restorative applications.
• To assess GA's etching pattern on dental hard tissues using microhardness and SEM.
• To determine GA's effectiveness on enamel and dentin resin bond strengths with different application modes and adhesive systems.

Main Methods:

• Microhardness testing of enamel and dentin before and after treatment with 35% GA, 35% PA, or distilled water.
• Microtensile bond strength testing on enamel and dentin.
• Scanning Electron Microscopy (SEM) for ultrastructural analysis of surface and interfacial interactions.

Main Results:

• GA and PA decreased enamel microhardness; GA was significantly less aggressive than PA.
• Both acids similarly decreased dentin microhardness.
• SEM showed comparable etching patterns for GA and PA, with a potentially thinner hybrid layer for GA.
• Dentin bond strengths were similar between GA and PA groups.
• Rubbing GA enhanced enamel bond strength.
• Scotchbond Universal (SBU) showed improved enamel bond strength with both GA and PA compared to other adhesives.

Conclusions:

• Glycolic acid effectively etches enamel and dentin surfaces.
• GA achieves bond strength comparable to traditional phosphoric acid.
• GA is a suitable surface etchant for adhesive dental restorative procedures.