Effect of tobacco and other habitual dietary staining agents on the optical properties of lithium disilicate molar crowns: A laboratory study.

Introduction: The treatment of choice for posterior teeth is full-coverage crowns, but these materials should not be color-affected by external factors such as tobacco use. This laboratory study aimed to evaluate the mean color change (ΔE*) values of lithium aluminum disilicate (LAD) full anatomical ceramic crowns after staining in different adverse materials consumed in different countries worldwide.

Methods: Ninety full anatomical crowns in the form of molars were constructed from LAD (Cerec Tessera blocks) with the use of computer-aided design/computerassisted manufacturing system. They were divided equally into nine groups, with 10 crowns for each group. The crowns were immersed for 15 days in different adverse materials (khat, shamma, yerba mate, snuff, soft drinks used daily as a mixture of fruit juice, Coca-Cola, Saudi coffee, and Nescafe). Instructions from the International Commission on Illumination were followed for color parameter measurements. The CIELab color space L* lightness value coordinate, a* red- green coordinate, and b* yellow-blue coordinate, were calculated before and after staining for 2 weeks. ΔE* values were calculated by spectrophotometry. One-way ANOVA followed by post hoc tests were used to assess significance differences between groups. The significance level was set at p<0.05.

Results: The ΔE* changed after immersion in all solutions except for the control group. The highest average ΔE* values and standard deviation were observed with yerba mate 6.3 ± 2.0, followed by shammah 4.6 ± 0.9, whereas the lowest ΔE* was recorded for the mixture of fruit juice 3.2 ±1.3. One-way ANOVA test showed a significant difference between the group of yerba mate, with p<0.001. Pearson's correlation coefficient test was used to assess the statistical relationship of ΔE* among groups. A highly positive significant correlation was found between shammah and Nescafe (r=0.798). A medium correlation was found between khat with yerba mate (r=0.520) and snuff and control groups (r=0.474), without significant differences.

Conclusions: The overall recorded ΔE* values for LAD full anatomical ceramic crowns following 2 weeks of staining in different staining media were marginally higher than the clinically acceptable values except for the fruit-juice group.