Protective effect of calcium silicate toothpaste on enamel erosion and abrasion in vitro

To compare in vitro the effect of a toothpaste containing fluoride (F), calcium silicate (CaSi) and sodium phosphate salts to conventional toothpaste (NaF) on human enamel specimens submitted to erosive and abrasive challenges.

48 sound and 48 enamel samples pre-treated with 1% citric acid were divided into 4 groups (n = 12): Group 1- Non-fluoride toothpaste; Group 2- NaF toothpaste (1450 ppmF); Group 3- CaSi toothpaste (1450 ppmF; MFP); Group 4- Erosion only. The samples were subjected to pH cycling (3 cycles/day; 90s; 1% citric acid, pH 3.6) and to abrasion for 7 days. After the 1^st and the last cycle, they were submitted to abrasion (15s, 1.5N load), using a brushing machine, soft toothbrush and toothpaste slurry (1:3; 15ml/sample) and then immersed in the slurry for 45s. Samples were immersed in artificial saliva between the challenges. Enamel loss was evaluated using profilometry on days 3 and 7. Data were analysed by ANOVA and Tukey's test (p < 0.05).

For sound enamel at baseline, mean (±SD) enamel loss (μm) for groups 1-4 on day 3 was 2.15 ± 0.35^a, 1.20 ± 0.22^b, 0.95 ± 0.19^b and 1.98 ± 0.32^a; on day 7 was 3.05 ± 0.40^a, 2.07 ± 0.32^b, 1.36 ± 0.33^c and 3.69 ± 0.27^d respectively. For acid-softened enamel at baseline, enamel loss on day 3 was 3.16 ± 0.19^a, 2.17 ± 0.14^b, 1.70 ± 0.11^c and 3.04 ± 0.19^a; on day 7 was 3.92 ± 0.25^a, 3.07 ± 0.13^b, 2.09 ± 0.15^c and 3.87 ± 0.25^a respectively.

Both F toothpastes led to significantly higher enamel protection from short-term erosion and abrasion in comparison to the non-F toothpaste and erosion only. In the longer term, CaSi toothpaste conferred significantly higher protection than NaF toothpaste.

The results showed that for the longer term the CaSi toothpaste provided significantly higher protection than the NaF toothpaste, which indicates a good potential of the former to help prevent erosive tooth wear.