Repeatability of dental shade by digital spectrophotometry in current, former, and never smokers

Abstract

Cigarette smoking contributes to poor oral health and dental discoloration. Therefore, stopping smoking may translate into measurable amelioration of dental shade indices. We compared dental shade parameters by digital spectrophotometry among current, former, and never smokers and verified their repeatability at 7 and 30 days. Dental shade parameters (CIE L*a*b* and corresponding whiteness index for dentistry-WID) were measured in current, former, and never smokers with a digital spectrophotometer (Vita Easyshade V) on three separate study visits: at baseline (day 0), at day 7, and day 30. Dental shade parameters were analyzed in 18 current, 18 former, and 20 never smokers. The repeatability of shade parameters was consistent in current, former, and never smokers. L*, a*, b*, and WID show significant short and long-term repeatability (p < 0.0001, by regression analyses). The mean (± SD) WID score of 13.42 (± 4.9) in current smokers was significantly lower compared to the WID score of 20.38 (± 5.3) in never smokers (p = 0.001). No significant differences were observed between current and former smokers and between former smokers and former smokers. Dental shade measurements by digital spectrophotometry were highly reproducible and showed that teeth whiteness of current smokers is substantially inferior compared to never smokers. Objective discrimination of dental shade can be a valuable regulatory science endpoint for investigating oral hygiene and dental aesthetics of consumer care products, smoking cessation medications, and tar-free tobacco products (e-cigarettes, heated tobacco products, oral nicotine products) for cigarette substitution.Clinical trial registration: the study was not registered in ClinicalTrials.gov considering that it is a pilot study, parts of a larger project with ID: NCT04649645.

Keywords: CIE L*a*b*; Dental shade; Digital spectrophotometer; Reproducibility; Smoking; Smoking cessation; Whiteness index for dentistry.

Conflict of interest statement

RP is full tenured professor of Internal Medicine at the University of Catania (Italy) and Medical Director of the Institute for Internal Medicine and Clinical Immunology at the same University. In relation to his recent work in the area of respiratory diseases, clinical immunology, and tobacco control, RP has received lecture fees and research funding from Pfizer, GlaxoSmithKline, CV Therapeutics, NeuroSearch A/S, Sandoz, MSD, Boehringer Ingelheim, Novartis, Duska Therapeutics, and Forest Laboratories. Lecture fees from a number of European EC industry and trade associations (including FIVAPE in France and FIESEL in Italy) were directly donated to vaper advocacy no-profit organizations. RP has also received grants from European Commission initiatives (U-BIOPRED and AIRPROM) and from the Integral Rheumatology and Immunology Specialists Network (IRIS) initiative. He has also served as a consultant for Pfizer, Global Health Alliance for treatment of tobacco dependence, CV Therapeutics, Boehringer Ingelheim, Novartis, Duska Therapeutics, ECITA (Electronic Cigarette Industry Trade Association, in the UK), Arbi Group Srl., Health Diplomats, and Sermo Inc. RP has served on the Medical and Scientific Advisory Board of Cordex Pharma, Inc., CV Therapeutics, Duska Therapeutics Inc, Pfizer, and PharmaCielo. RP is also founder of the Center for Tobacco prevention and treatment (CPCT) at the University of Catania and of the Center of Excellence for the acceleration of HArm Reduction (CoEHAR) at the same University, which has received support from Foundation for a Smoke-Free World to conduct 8 independent investigator-initiated research projects on harm reduction. RP currently involved in a patent application concerning an app tracker for smoking behavior developed for ECLAT Srl. RP is also currently involved in the following pro bono activities: scientific advisor for LIAF, Lega Italiana Anti Fumo (Italian acronym for Italian Anti-Smoking League), the Consumer Advocates for Smoke-free Alternatives (CASAA) and the International Network of Nicotine Consumers Organizations (INNCO); Chair of the European Technical Committee for standardization on “Requirements and test methods for emissions of electronic cigarettes” (CEN/TC). The other authors declare that they have no conflict of interest.

© 2022. The Author(s).

Figures

Fig. 1

Study Design

Fig. 2

Short-term repeatability (V2 vs. V1) of WID scores in Never Smokers. A shows the scatter plot of regression analysis between visit 2 (V2) and visit 1 (V1) for WID scores. B shows the difference between the measurements taken at V1 and V2 concerning the mean in each subject in the Bland Altman plot

Fig. 3

Long-term repeatability (V3 vs. V1) of WID scores in Never Smokers. A shows the scatter plot of regression analysis between visit 3 (V3) and visit 1 (V1) for WID scores. B shows the difference between the measurements taken at V1 and V3 concerning the mean in each subject in the Bland Altman plot

Fig. 4

Short-term repeatability (V2 vs. V1) of WID scores in Current Smokers. A shows the scatter plot of regression analysis between visit 2 (V2) and visit 1 (V1) for WID scores. B shows the difference between the measurements taken at V1 and V2 concerning the mean in each subject in the Bland Altman plot

Fig. 5

Long-term repeatability (V3 vs. V1) of WID scores in Current Smokers. A shows the scatter plot of regression analysis between visit 3 (V3) and visit 1 (V1) for WID scores. B shows the difference between the measurements taken at V1 and V3 concerning the mean in each subject in the Bland Altman plot

Fig. 6

Short-term repeatability (V2 vs. V1) of WID scores in Former Smokers. A shows the scatter plot of regression analysis between visit 2 (V2) and visit 1 (V1) for WID scores. B shows the difference between the measurements taken at V1 and V2 concerning the mean in each subject in the Bland Altman plot

Fig. 7

Long-term repeatability (V3 vs. V1) of WID scores in Former Smokers. A shows the scatter plot of regression analysis between visit 3 (V3) and visit 1 (V1) for WID scores. B shows the difference between the measurements taken at V1 and V3 concerning the mean in each subject in the Bland Altman plot

Fig. 8

Individual WID scores among Current, Former, and Never smokers. The diamond points with a black horizontal bar illustrate the means of each study group. High WID values indicate whiter teeth, with low WID values showing discolored or much darker teeth