Comparative Analysis on Colour Changes of Nano and Microhybrid Composite with Exposure to Cigarette and Cigar Smoke: An In-vitro Analysis

Introduction: The aesthetic longevity of dental composites is crucial, especially for smokers, as smoke exposure can cause discolouration. Cigarette and cigar smoke may affect the colour stability of restorations, raising concerns for both patients and clinicians. Therefore, it is necessary to study the types of discolouration caused by both smoking agents and the selection of composite materials. Aim: To assess and compare the colour changes in nanohybrid and microhybrid composites when exposed to cigarette and cigar smoke. Materials and Methods: This single-blinded, in-vitro study was conducted in the Department of Conservative Dentistry and Endodontics at KM Shah Dental College and Hospital, Sumandeep Vidyapeeth, over a duration of one month (1st Oct to 31st Oct 2024). A total of 120 composite specimens were prepared in a standardised manner. All samples were then randomly allocated into two groups: Group 1 (Nanohybrid, n=60) and Group 2 (Microhybrid, n=60) were each further divided into three subgroups: Subgroup A (Cigarette smoke exposure, distributed as A1 and A2, n=20 each), Subgroup B (Cigar smoke exposure, distributed as B1 and B2, n=20 each), and Subgroup C (Control- artificial saliva, distributed as C1 and C2, n=20 each). Pre-exposure Commission Internationale de l’Éclairage (CIE) Value (L*), Saturation (a*), and Hue (b*) value of all the samples were recorded. A customised smoke chamber was created simulating oral smoking. In this smoke chamber, all the samples were exposed to smoke for 15 days testing period following the exposure criteria. Postexposure CIE L*a*b* value of all the samples was recorded. Colour changes (ΔE) were measured using Adobe Photoshop. Statistical analysis was performed using One-way Analysis of Variance (ANOVA) and Tukey’s post-hoc test. The data was analysed using IBM Statistical Package for Social Sciences (SPSS) version 21.0; keeping confidence interval at 95% and a p-value