Influence of Smoking and Finishing/Polishing on Composite Color Stability

Abstract

To assess the influence of conventional cigarette and heated tobacco product smoking and finishing/polishing systems on color stability of a nanohybrid composite. Thirty-six discs (2mm thickness/6mm diameter) fabricated from nanohybrid composite (Palfique LX5, Tokuyama, Japan) were divided to 6 groups according to: tobacco product (conventional cigarette/LM, Philip Morris International Inc., Egypt; and heated tobacco/Heets, Russet, Philip Morris International Inc., Italy); and finishing/polishing system (control /discs cured against Mylar strip; finishing discs system/Diamond Master Kit, FGM, Brazil; two-step polishing system/DIACOMP PLUS TWIST, EVE, Germany). All specimens were wet ground with medium grit finishing stone (komet, Germany) as baseline before performing finishing and polishing protocols. After finishing/polishing, specimens were exposed to 600 cigarettes/Heets (20/day) representing 30 days of medium smoking behavior. Color parameters were measured using VITA Easyshade Advance 4.01 spectrophotometer (VITA Zahnfabrik, Germany). Change in color (∆E) was analyzed using One-Way ANOVA/Tukey's and independent student t-test. For cigarettes, no significant difference in ∆E values between finishing/polishing groups. For Heets, ∆E value of polishing system groups was significantly higher that control group; however, ∆E value of finishing discs system was statistically similar to that of control and polishing system groups. Cigarettes displayed significantly higher ∆E values than Heets for all finishing/polishing systems. Conventional cigarette smoking produced an increased color change in composite compared to heated tobacco product smoking. Both finishing discs and two-step polishing system resulted in similar change in color of tested composite.