Effect of Cigarette Smoking on the Surface Roughness, Color, and Translucency of Zirconia Produced by Additive and Subtractive Manufacturing

OBJECTIVE: To compare the surface roughness, color stability, and translucency of zirconia produced by additive manufacturing (AM) and subtractive manufacturing (SM) after exposure to cigarette smoking. MATERIALS AND METHODS: A total of 60 disc-shaped specimens were fabricated from 2 methods: AM (INNI Cera BCM W500/1000) and SM (VITA YZ T). All specimens were polished. Baseline surface roughness and color coordinates were measured. All specimens were immersed in artificial saliva, and four subgroups (n = 15) were defined based on exposure to cigarette smoking: AM-Smoke (AM-S), AM-Artificial Saliva (AM-AS), SM-Smoke (SM-S), and SM-Artificial Saliva (SM-AS). After 30 days of cigarette exposure (10 cigarettes per day), the measurements were repeated. Color difference (ΔE) and relative translucency parameter (RTP) were calculated using the CIEDE2000. The data were analyzed using three-way mixed-design ANOVA and one-way ANOVA (α = 0.05). RESULTS: Smoking exposure increased the roughness of each group (p < 0.05). SM-S had a statistically higher color difference (p < 0.05). Only the AM-S group showed a significantly reduced RTP and ΔL (p < 0.05). All color and RTP differences were below the acceptability threshold. CONCLUSIONS: Cigarette smoking increased the surface roughness of AM and SM zirconia. Within acceptable limits, cigarette smoking negatively affected the translucency and lightness of AM zirconia and the color stability of SM zirconia. CLINICAL SIGNIFICANCE: Although both manufacturing methods demonstrate clinically acceptable color stability, translucency, and surface roughness, exposure to cigarette smoke affects their optical properties differently. The manufacturing method should be considered for the optical performance of zirconia. Long-term exposure and intraoral aging should be evaluated in future research.