Effect of a chitosan additive to a Sn²⁺-containing toothpaste on its anti-erosive/anti-abrasive efficacy—a controlled randomised in situ trial

It is well known that Sn²⁺ is a notable anti-erosive agent. There are indications that biopolymers such as chitosan can enhance the effect of Sn²⁺, at least in vitro. However, little information exists about their anti-erosive/anti-abrasive in situ effects. In the present in situ study, the efficacy of Sn²⁺-containing toothpastes in the presence or absence of chitosan was tested.

Ten subjects participated in the randomised crossover study, wearing mandibular appliances with human enamel specimens. Specimens were extraorally demineralised (7 days, 0.5 % citric acid, pH 2.6; 6 × 2 min/day) and intraorally exposed to toothpaste suspensions (2 × 2 min/day). Within the suspension immersion time, one half of the specimens were additionally brushed intraorally with a powered toothbrush (5 s, 2.5 N). Tested preparations were a placebo toothpaste (negative control), two experimental toothpastes (F/Sn = 1,400 ppm F⁻, 3,500 ppm Sn²⁺; F/Sn/chitosan = 1,400 ppm F⁻, 3,500 ppm Sn²⁺, 0.5 % chitosan) and an SnF₂-containing gel (positive control, GelKam = 3,000 ppm Sn²⁺, 1,000 ppm F⁻). Substance loss was quantified profilometrically (μm).

In the placebo group, tissue loss was 11.2 ± 4.6 (immersion in suspension) and 17.7 ± 4.7 (immersion in suspension + brushing). Immersion in each Sn²⁺-containing suspension significantly reduced tissue loss (p ≤ 0.01); after immersion in suspension + brushing, only the treatments with GelKam (5.4 ± 5.5) and with F/Sn/chitosan (9.6 ± 5.6) significantly reduced loss [both p ≤ 0.05 compared to placebo; F/Sn 12.8 ± 6.4 (not significant)]

Chitosan enhanced the efficacy of the Sn²⁺-containing toothpaste as an anti-erosive/anti-abrasive agent.

The use of Sn²⁺- and chitosan-containing toothpaste is a good option for symptomatic therapy in patients with regular acid impacts.