Effect of cigarette smoking and alcohol consumption on the colour stability of various orthodontic aligners—an in vitro study

Abstract Aim The present study aimed to analyse and compare the colour stability of three types of orthodontic clear aligners following in vitro exposure to cigarette smoking and alcohol by using the attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) method. Materials and methods The study included 144 clear aligners divided into 3 groups of 48 each based on different manufacturers and comprised: Group A—Invisalign, Group B—KiyoClear, Group C—OrthoFX. The samples were tested for colour stability related to translucency after exposure to cigarette smoke and alcoholic drinks at times, T0: before exposure (as-received aligner), T1: after a seven-day exposure, T2: after a fourteen-day exposure using the ATR-FTIR method. Data were analysed using one-way ANOVA, Tukey’s post hoc test, Repeated Measures of ANOVA, Bonferroni’s post hoc test, and Independent Student’s t test accepting a p -value < 0.05. Results There was a statistically significant difference in the mean translucency values between the three groups at T0, T1, and T2. All groups exhibited mean translucency values which significantly decreased over time following smoking and alcohol exposure. Conclusion: OrthoFX, KiyoClear and Invisalign showed decreasing translucency values following smoking and alcohol exposure, with smoking causing a greater reduction. Both types of exposure should be avoided to maintain an aesthetic orthodontic appearance.