In Situ Clinical Study Investigating Abrasive Effects of Three Toothpastes

Objectives: The aim of the in-situ study was to compare the abrasive effect of an ultra low abrasive toothpaste with a moderate and a high abrasive toothpaste, brushed on human dentine for 10 days, measured with contact and non-contact profilometry.

Methods: The study design was single centre, single blind, randomised, split mouth, 2 period, four-treatment cross-over, in-situ study in 20 healthy subjects. Subjects wore bi-lateral lower buccal appliances each fitted with four dentine sections. Each subject received 2 of the study treatments (one on the right and one on the left side) during each of the 2 study periods. The 10 treatment days per period comprised of brushing the dentine samples 3 times a day with an ultra low relative dentine abrasion (RDA) toothpaste, a moderate RDA toothpaste, a high RDA toothpaste or water as the negative control. Dentine samples were measured at baseline, day 5 and 10 by contact profilometry, and baseline and day 10 with non-contact profilometry.

Results: Comparison of the contact and non-contact profilometry methodology broadly yielded similar findings. Results from brushing with the moderate and high RDA pastes showed significantly (p<0.0001) more abrasion to dentine than brushing with the ultra low RDA paste or brushing with water after 10 days. The dentine loss following tooth brushing with the ultra low RDA paste was not significantly different from brushing with water, after 10 days.

Conclusions: The methodology successfully showed clear differentiation between the amount of dentine loss following tooth brushing with an ultra low RDA toothpaste compared to brushing with a moderate or a high RDA toothpaste in this in situ model. Dentine loss following brushing with the ultra low RDA paste showed a comparable degree of abrasion to brushing with water. Utilization of this methodology provides greater clinical relevance than just RDA testing alone.