Acid-etching and hydration influence on dentin roughness and wettability

Area of Science:

• Dental Materials Science
• Biomaterials Engineering
• Surface Chemistry

Background:

• Effective adhesion of dental restorative materials to dentin is crucial for successful operative and preventive dentistry.
• Dentin surface properties, specifically wettability and roughness, are critical factors influencing bond strength.

Purpose of the Study:

• To investigate variations in water contact angle and roughness on superficial and deep dentin surfaces.
• To evaluate the effects of polishing, etching, dehydration, and rehydration on dentin substrate properties.

Main Methods:

• Utilized Atomic Force Microscopy (AFM) for roughness quantification and Axisymmetric Drop Shape Analysis (ADSA) for contact angle measurements.
• Tested dentin samples from third molars under hydrated, polished, etched (10% H3PO4), dehydrated, and rehydrated conditions.
• Statistical analysis included two-way Repeated Measures ANOVA with Tukey's HSD post-hoc tests at p < 0.05.

Main Results:

• Etching increased both wettability and roughness. Desiccation led to a significant decrease in wettability while roughness continued to increase.
• Rehydration restored water contact angles to levels similar to the etched state.
• Intertubular roughness was not significantly affected by dentin depth, but deep dentin exhibited lower water contact angles.

Conclusions:

• Dentin depth and dehydration significantly alter surface properties, exposing hydrophobic moieties.
• These alterations can negatively impact the bonding of hydrophilic dental primer systems to dentin.
• Understanding these surface changes is vital for optimizing dental adhesive protocols.