Effect of airborne particle abrasion on the surface roughness of high-translucent 5Y-PSZ following simulated long-term oral aging: a non-contact optical profilometric in-vitro study

OBJECTIVE: This study aimed to evaluate the effects of airborne particle abrasion (APA) using 50 μm Al₂O₃ and 100 μm glass microbeads on the surface roughness of high-translucent 5Y-PSZ and to assess the stability of these surface modifications following simulated long-term oral aging. Sixty zirconia discs (Shofu ZR Lucent) were randomly allocated into three groups (n = 20): the control, Al₂O₃, and glass microbead groups. Long-term oral aging was simulated by 25,000 thermocycles (5-55 °C) and 30 days of immersion in cold brew coffee. The surface roughness was analyzed by 2D non-contact optical profilometry at baseline, post-thermocycling, and post-coffee immersion. RESULTS: Compared with 100 μm glass microbeads (Ra = 1.93 ± 0.11 μm) and the control group (Ra = 0.14 ± 0.14 μm), the APA with 50 μm Al₂O₃ particles (Ra = 2.28 ± 0.06 μm; p < 0.001) produced the highest surface roughness, which was corroborated by profilometry line scans. The surface modifications remained stable following aging, although the Rq and Rp parameters demonstrated greater sensitivity to subtle clinical changes than Ra (p < 0.05). APA using 50 μm Al₂O₃ produced the highest surface roughness and most stable modification, highlighting the clinical need to balance micromechanical retention with the preservation of structural integrity for the long-term success of 5Y-PSZ restorations.