Influence of electronic cigarette vapour on the in vitro chromatic stability of different nanohybrid composite resins

Objective: The purpose of this study was to compare the chromatic differences (ΔE) of three nanohybrid composite resins (Filtek™ Z350 XT, FORMA™ and Palfique LX5) after increasing exposures (0, 250, 500, 750, 1,000, 1,250 and 1,500 puffs) to e-cigarette vapours. Materials and methods: The study was conducted with an in vitro experimental design, in which a total of 66 resin discs measuring 10 mm × 2 mm were used and distributed as follows: 22 discs of each brand of resin tested. After 24 hours storage in water at 37°C and 500 cycles of thermal cycling (5°C–55°C), they were exposed to the vapour of a ‘Vuse’ brand electronic cigarette dispensed in an artificial vacuum system, graded into levels consisting of six puff each. Colour parameters were measured according to the CIELab system with a Konica Minolta CR-400 colorimeter before (baseline) and after each cycle of puffs, and the difference in colour (ΔE) was calculated. For statistical analysis, the mixed analysis of variance (ANOVA) test and the post hoc test of Games‑Howell, was used, with a confidence level of 95%. Results: Filtek™ Z350 XT resin had an average ΔE value of 3.239 ± 1.30; FORMA™ showed an ΔE value of 4.737 ± 1.672, and Palfique LX5 had a mean ΔE of 1.614 ± 0.867. Significant differences were found between resin brands (p < 0.001), while increasing puffs did not significantly influence ΔE within each resin (p > 0.05). Conclusion: Chromatic stability of composites after exposure to e-cigarette vapours varied depending on the material brand, with FORMA™ resin showing clinically unacceptable chromatic differences, whereas Filtek™ Z350 XT and Palfique LX5 resins showed clinically acceptable chromatic differences, with the latter showing greater resistance to colour change and therefore greater chromatic stability. These findings serve as a guide in decision-making relative to the selection of restorative materials indicated for patients with vaping habits.