Single-use and six-week effects of a non-tobacco nicotine pouch on dental plaque characteristics: a randomized crossover study with observational follow-up

This study measures the short- and long-term acidogenicity in dental biofilms of tobacco-based snus users who switch to nicotine pouches (ZYN® Dry) for delivering nicotine. ZYN Dry contains microcrystalline cellulose (MCC) and maltitol rather than grounded tobacco leaves. Although MCC and maltitol are not typically associated with changes in biofilm acidogenicity, prolonged exposure (30–60 min) may cause vulnerability and increase the caries risk. This study consists of two parts. Part A was an open-label, randomized, four-way crossover study involving single-dose administration in 18 participants. It tested flavored and unflavored ZYN products as well as 10% sucrose and 10% xylitol rinses as controls. The pouch was placed in the vestibule for 60 min, while the control mouth rinses were performed for one minute each. Part B was an open-label, observational, and follow-up study which lasted for six weeks and included 56 participants. Exposure to 10% sucrose was tested at baseline (week 0) and after 2, 4, and 6 weeks of ZYN use. Dental plaque acidogenicity was measured on two approximal surfaces in the upper jaw at baseline and up to 60 min after administration using the microtouch method. Areas under the curve for pH 7.5 were calculated (AUC7.5). Six tooth surfaces were used to score the amount of plaque (0–3). Ethical approval and informed consent were obtained. After single-dose administration (Part A), AUC7.5 for dental plaque acidogenicity was significantly less pronounced for the ZYN products and xylitol compared to sucrose. There were no statistical differences between the flavored and unflavored ZYN products. Ad libitum administration of ZYN (Part B) resulted in a significant reduction in the AUC7.5 for plaque acidogenicity compared to baseline. No statistically significant changes in plaque amount were observed during the six-week study. In healthy tobacco-based snus users, dental plaque acidogenicity decreased following ad libitum use of ZYN nicotine pouches, suggesting a reduced acidogenic response under the conditions of this study. This clinical trial was retrospectively registered at: https://www.isrctn.com/ (ISRCTN16087707).