Influence of Surface Treatments and Thermocycling on Wettability, Roughness, and Bond Strength of Lithium Disilicate CAD/CAM Ceramics

This study evaluated the effects of surface treatments and thermal aging on the surface properties and bonding performance of three CAD/CAM lithium disilicate ceramics: Amber Mill, Vita Suprinity, and IPS e.max CAD. A total of 150 specimens were divided into five groups: control, hydrofluoric acid etching, airborne-particle abrasion, and Er,Cr:YSGG laser irradiation at 2 W and 3 W. Half of the samples underwent thermocycling (10,000 cycles, 5-55 °C). Surface roughness, water contact angle, and microshear bond strength were measured, and failure modes were analyzed. Ceramic type and surface treatment significantly affected outcomes. Amber Mill generally exhibited higher roughness, while IPS e.max CAD achieved the greatest bond strength. Hydrofluoric acid etching consistently enhanced bonding in Vita Suprinity and IPS e.max CAD, whereas 2 W laser irradiation improved bond strength without notably changing roughness. In contrast, 3 W laser treatment increased contact angle, reducing wettability. Thermocycling raised bond strength in control and sandblasted groups but overall increased contact angle. Adhesive failures predominated, though cohesive and mixed failures became more common after aging. Overall, ceramic type, surface treatment, and thermal aging interactively influenced adhesion. Hydrofluoric acid etching remains the most effective treatment, while low-power laser irradiation offers a promising, less invasive alternative.