Influence of Airborne-Particle Abrasion and Thermal Cycling on Enamel Bond Strength and Roughness of Lithium...

This in vitro study investigated the effect of a self-etching ceramic primer (Monobond Etch & Prime [MEP]), with or without aluminum oxide airborne-particle abrasion, on the surface roughness, and microtensile bond strength (μTBS) of lithium disilicate bonded to enamel, compared with the conventional hydrofluoric acid plus silane (HF + S).

Lithium disilicate specimens (10 × 10 × 4 mm) were assigned to four groups: HF + S airborne-particle abraded (HF + S[a]), HF + S polished (HF + S[p]), MEP airborne-particle abraded (MEP[a]), and MEP polished (MEP[p]). Surface roughness (ΔS_a) was assessed after conditioning, and specimens were bonded to bovine enamel with resin cement. μTBS was tested before and after thermo cycling (10,000 cycles, 5°C/55°C).

Airborne-particle abrasion significantly increased ΔS_a (HF + S[a]: 1.16 ± 0.12 μm; MEP[a]: 0.85 ± 0.02 μm) compared to polished specimens (HF + S[p]: 0.47 ± 0.04 μm; MEP[p]: 0.38 ± 0.04 μm). HF + S and MEP performed similarly in all conditions (p > 0.05). Airborne-particle abraded surfaces consistently exhibited higher μTBS than polished ones (p < 0.05). Thermo cycling significantly reduced μTBS in all groups. Mixed and cohesive failures predominated before thermo cycling, whereas adhesive failures increased after.

MEP and HF + S demonstrated comparable bonding to enamel. Airborne-particle abrasion enhanced both surface roughness and μTBS, regardless of conditioning strategy. Although thermo cycling reduced adhesion in all groups, the decline was similar across treatments.