Effect of cigarette smoke on color stability and surface roughness of different soft denture lining materials. An in vitro study.

Purpose: To evaluate the effect of cigarette smoke on the surface roughness and color stability of three different soft denture liners.

Methods: Three commonly used commercially available, chair-side, long-term vinyl polysiloxane soft denture liners were used for this study [Sofreliner Tough (S) Soft, Silagum Comfort Soft Relining, and GC Reline Soft\. Thirty disk-shaped specimens of each material, with a diameter of 25 mm and thickness of 2 mm, were fabricated. Initial color and surface roughness readings were recorded. The specimens of each group were randomly divided into two groups (n= 15): the control group (C) and the study group (S). The control group specimens were stored in distilled water and the study group samples were exposed to cigarette smoke in a custom-made smoking chamber. Final color and surface roughness readings were recorded. A single operator performed all the measurements. The differences in color and surface roughness were calculated. Statistical analysis was performed using two-way ANOVA, post-hoc Tukey test, and paired t-test. For all the analyses, a P< 0.05 was regarded as statistically significant.

Results: After exposure to smoke, all groups showed a significantly perceptible color change (ΔE > 3.7). The greatest color change was seen in the Silagum group (ΔE= 8.94 ± 0.42), followed by the Sofreliner group (ΔE= 7.85 ± 0.47), with the least change in the GC reline group (ΔE= 3.87 ± 0.46). The mean color change after smoke exposure showed a statistically significant difference among all three study groups. The highest change in surface roughness was observed in the Silagum group (ΔR= 0.687 ± 0.14) followed by the GC reline group (ΔR= 0.265 ± 0.12), with the least change in the Sofreliner group (ΔR= 0.238 ± 0.06). There was a statistically significant difference between each group before and after exposure to smoke. Exposure to cigarette smoke caused significant changes in the color and surface roughness of all three soft denture liners tested in this study. The extent of these changes varied for each material.

Clinical Significance: Proper selection of soft denture liners is essential to avoid premature replacement, due to esthetic and hygiene reasons in cigarette smokers.