Effect of cigarette smoking on the optical properties of contemporary dental ceramics: an in-vitro analysis

Background: Cigarette smoking is the most common form of tobacco use worldwide. With the frequent introduction of new dental materials, the effect of smoking on their optical properties such as long term color stability, should to be thoroughly investigated.

Objective: This in-vitro study aims to investigate the effect of smoking on the optical properties of contemporary dental ceramics used currently for restoration of teeth.

Methods: Five different materials in two shades (B1 and C1) were used with 15 samples from each pressable lithium disilicate (Emax), layered lithium disilicate (Lmax), porcelain fused to metal (PFM), monolithic zirconia (MZr) and layered zirconia (LZr) were used (n = 75). The samples were exposed to conventional cigarette smoke and color stability was assessed at four different time intervals i.e., baseline, 1 week, 1 month and 6 months. CIELAB color space (CIE L*a*b*) values were used to evaluate the color difference (ΔE). A one-way analysis of variance (Anova) was used for statistical analysis of ΔE. Significant P-value was kept as <0.05, followed by Tukey post-hoc test.

Results: All test materials demonstrated significant color differences (ΔE) after exposure to cigarette smoke (p < 0.05). For shade B1, the highest change in shade ΔE 17.02 was exhibited by Lmax, whereas the least change in shade was exhibited by Emax followed by PFM at values of ΔE 10.11 and 11.2 respectively. For shade C1, the highest change (11.47) in shade at 6 months was demonstrated by MZr, whereas lowest values of ΔE were exhibited by Emax (7.52).

Conclusions: Traditional smoking causes significant change in shade of dental ceramics which can affect the esthetics of the patients. All material samples tested showed the values of ΔE > 3.3 which is higher than the acceptable range. Lowest color change was observed in Emax and PFM.