Influence of surface conditioning on ceramic microstructure and bracket adhesion

Area of Science:

• Dental Materials Science
• Biomaterials Engineering
• Orthodontic Technology

Background:

• Dental ceramics are widely used in orthodontics.
• Effective bracket adhesion to ceramic surfaces is crucial for treatment success.
• Various conditioning methods aim to optimize this bond, but their efficacy varies.

Purpose of the Study:

• To evaluate the impact of different conditioning methods on ceramic microstructures and bracket adhesion.
• To compare conventional hydrofluoric acid (HF), buffered hydrofluoric acid (BHF), and sandblasting for ceramic surface treatment.
• To assess the influence of conditioning on bracket-composite-ceramic interface integrity.

Main Methods:

• Four ceramic types (feldspathic, leucite, leucite-free, fluorapatite) were conditioned using 5% HF, 9.6% BHF, or sandblasting.
• Silane coupling agents were applied before bracket bonding.
• Shear bond strength (SBS) was tested, and the adhesive remnant index (ARI) was used for interface evaluation.
• Electron microscopy examined conditioned surfaces.

Main Results:

• Conventional 5% HF and sandblasting yielded significantly higher SBS (34.11 MPa and 32.86 MPa) than 9.6% BHF (12.49 MPa).
• Etching time and sandblasting particle type did not statistically influence bond strength.
• Higher ARI scores were observed with conventional 5% HF and sandblasting compared to BHF.
• Leucite and leucite-free ceramics showed surface roughness differences, but this did not affect SBS.

Conclusions:

• The conditioning procedure itself is the primary determinant of bracket adhesion to ceramics.
• Conventional HF and sandblasting are effective for enhancing bracket adhesion.
• While sandblasting ensures sufficient adhesion, it carries a risk of ceramic surface damage.