Does acid etching morphologically and chemically affect lithium disilicate glass ceramic surfaces?

Area of Science:

• Dental Materials Science
• Biomaterials Engineering
• Surface Chemistry

Background:

• Lithium disilicate glass ceramic is a widely used dental biomaterial.
• Surface treatment is critical for achieving durable bonds between ceramics and resin cements.
• Understanding the effects of different etching agents on ceramic surface properties is essential for clinical success.

Purpose of the Study:

• To evaluate the impact of hydrofluoric acid (HF) and phosphoric acid (Phos) etching on the surface characteristics and bond strength of lithium disilicate glass ceramic.
• To compare the effectiveness of different surface treatments, including airborne particle abrasion (AA), acid etching, and silane application, on ceramic-to-cement adhesion.

Main Methods:

• Specimens were treated with airborne particle abrasion (50-μm alumina), etching (5% HF or 36% Phos), and/or silane coupling agent (Si).
• Stainless steel rods were cemented using a self-adhesive resin cement.
• Shear bond strengths were measured after storage in distilled water at 37°C for 24 hours.

Main Results:

• Acid etching (HF or Phos) created a porous surface, unlike the microgrooves from AA.
• Treatments involving HF or Phos etching combined with silane application significantly increased bond strength compared to controls.
• HF etching alone demonstrated higher bond strength than AA alone.

Conclusions:

• Etching with HF or Phos effectively enhances the bond strength between lithium disilicate glass ceramic and self-adhesive resin cement.
• These acid etching methods promote adhesion without inducing detrimental microcrack formation in the ceramic structure.