Some effects of water on dentin bonding

Area of Science:

• Dental Materials Science
• Polymer Chemistry
• Adhesion Science

Background:

• Hydroxyethylmethacrylate (HEMA)-based dentin primers are crucial for dental restorations.
• Solvent choice and application parameters influence primer performance and resin-dentin bonding.

Purpose of the Study:

• To evaluate the impact of water versus acetone as solvents in HEMA-based dentin primers on bond strength.
• To assess the effect of primer application time on bond strength.
• To determine the influence of water contamination on bonding resin conversion.

Main Methods:

• HEMA primers with water or acetone were applied to moist dentin for 30 or 120 seconds.
• Shear bond strength was measured after 30 days of water storage.
• Fourier Transform Infrared Spectroscopy (FTIR) assessed bonding resin conversion with varying water content.

Main Results:

• Acetone-based primers yielded significantly higher bond strengths (21.5-22.2 MPa) than water-based primers (7.0-16.2 MPa).
• Water-based primers showed improved bond strength with longer application times but remained inferior to acetone groups.
• Bonding resin conversion decreased from 53.5% to ~25% with the addition of 0.2 mL water per mL resin.

Conclusions:

• Water is an inferior solvent for HEMA-based dentin primers compared to acetone, resulting in lower bond strength and requiring longer application times.
• Water contamination significantly hinders bonding resin polymerization, likely due to interference with resin systems.