Protective Effects of Calcium Silicate Products on Acid Softened Enamel

Objectives: To evaluate the protective effects of calcium silicate, sodium phosphate salts and fluoride containing toothpaste and dual-phase gel on acid softened enamel samples subjected to erosion/abrasion.
Methods: Human enamel specimens were partially coated with nail varnish and pre-eroded with 1% citric acid (pH3.6) for 10min. Specimens (n=12/group) were randomly assigned to the following treatments: 1. Placebo toothpaste (non-F); 2. NaF toothpaste (1450ppm F); 3. Calcium silicate and sodium phosphate salts toothpaste (1450ppm F as MFP); 4. Toothpaste as 3 plus dual-phase gel containing (i) calcium silicate and sodium phosphate salts (1450ppm F as MFP) and (ii) 1450ppm F as NaF; 5. Erosion only. During 7days, specimens underwent 3 cycles of 90s/day in 1% citric acid (pH3.6). Except for group 5, after the first and the last daily cycle, specimens were subjected to abrasive challenges (15s, 150g load), using a brushing machine, toothbrush and toothpaste:water slurry (1:3) and then immersed for 45s in the slurry without brushing. Group 4 also had the dual-phase gel applied for 3min after the second daily brushing for 3days. Specimens were immersed in artificial saliva at all other times. Enamel loss (µm) was measured by contact profilometry after 3 and 7days.
Results: Mean (SD) enamel loss (µm) values are shown in table. Treatments with different letters were significantly different (p<0.05, ANOVA, Tukey). Percentage enamel protection versus erosion only was 0, 27, 57 and 67% for groups 1-4, respectively, after 7days.
Conclusions: Regardless of the time of treatment, both calcium silicate treatment groups provided significantly greater protection of enamel towards erosion associated with abrasion when compared to the non-F toothpaste, NaF toothpaste and erosion only. Moreover, the best protection was obtained for the combination calcium silicate toothpaste/dual-phase gel.