Strittholt CA, McMillan DA, He T, Baker RA, Barker ML. A Randomized Clinical Study to Assess Ingestion of Dentifrice by Children. Regulatory toxicology and pharmacology 2015 Dec 22. pii: S0273-2300(15)30143-4. doi: 10.1016/j.yrtph.2015.12.008.
This study investigated whether there was a difference in amounts of dentifrice ingested by children based on age using pea-sized instructions. The study had a randomized, single-blinded, 3-period, crossover design modelled after Barnhart et al. (1974) with one regular-flavored and two specially-flavored dentifrices used ad libitum. Subjects were enrolled in three groups: 2-4, 5-7, and 8-12 years. They were instructed to brush at home as they would normally with each dentifrice for 3 weeks (9 weeks total). On weekly study-site visits, subjects brushed with the assigned dentifrice containing a lithium marker to measure the amount of dentifrice ingested and used. Averaging across dentifrices, amounts ingested were: 0.205g (2-4yr), 0.125g (5-7yr) and 0.135g (8-12yr), demonstrating 2-4 year-olds ingested significantly more than older children (p≤0.002). Averaging across dentifrices, amounts used were: 0.524g (2-4yr), 0.741g (5-7yr) and 0.978g (8-12yr) suggesting an age-related effect (p<0.01). Findings also showed that ingestion amount for specially-flavored dentifrices may increase relative to regular-flavored dentifrice for children 2-7 years-old. This research demonstrated that dentifrice ingestion amount decreased significantly with age while usage amount increased with age. Importantly, ingestion and usage levels in younger children reflect “pea-sized” direction and were numerically lower than historical levels reported prior to this direction.