Acid-neutralizing Capacity of S-PRG Filler-containing Toothpaste

Objective:

S-PRG filler, which has a 3-layer structure including a glass-ionomer phase, shows bioactive effects (formation of acid-resistant layer, strengthening of tooth structure, anti-plaque effect, dentin remineralization, etc.) derived from its ability to release various ion species, as reported by several studies. This study aimed to evaluate ion-releasing ability and acid-neutralizing capacity of S-PRG filler-containing toothpaste.

Methods:

S-PRG filler-containing toothpaste (0.02g) was added to lactic acid solution (20mL, pH=3.8), and time-dependent pH change in the solution was measured using a pH meter. Test toothpastes prepared with different contents of S-PRG filler (filler particle size/content) were: PRG3-5 (3µm/5wt%), PRG3-30 (3µm/30wt%); and PRG-0 (0wt% of S-PRG filler) as control. For comparison, Colgate (Col) and Crest (CR) were used.

At 10min after addition of test toothpastes to lactic acid solution, elemental analysis of ion species (Al, B, F, Na, Si and Sr selected from glass composition of S-PRG filler) released from S-PRG filler contained in test toothpastes were also performed using ICP atomic emission spectrometry and fluoride ion electrode method. Data were statistically analyzed (ANOVA, Tukey's, p<0.05).

Results:

Addition of minute amounts of S-PRG filler-containing toothpastes to lactic acid solution caused release of 6 elements (Al, B, F, Na, Si, Sr), and induced a shift in the pH of the solution from the acidic to neutral region. The initial pH increase was similar for S-PRG filler-containing groups regardless of the content of S-PRG filler, but after 1min the behavior in the pH rise varied by the content of S-PRG filler, with PRG3-30 having the highest acid-neutralizing capacity. PRG-0, Col and CR exhibited almost no pH increase.

Conclusion:

Test results revealed that S-PRG filler-containing toothpaste has acid-neutralizing capacity that shifted the pH of acidic solution to the neutral region due to the presence of six ions released from S-PRG filler.