Efficacy of Stevioside sweetener on pH of plaque among young adults

Abstract

Background: Stevioside is a natural herbal sweetener extracted from Stevia rebaudiana. An in vitro
study has proved the antibacterial efficacy of 0.2% Stevia aqueous solution against Streptococcus
mutans and Lactobacillus acidophilus, and the present study was conducted to clinically evaluate
the efficacy of Stevia leaf extract and Stevia product on plaque pH, when compared with sucrose
solution.
Materials and Methods: A clinical trial was conducted among a sample of 22 undergraduate
students who volunteered. After obtaining consent, students were instructed not to brush at night
and not to use any mouth rinse during the course of the study. Baseline plaque pH was measured
in situ using digital pH meter. Students were asked to rinse for 1 min with 0.2% aqueous solution
of Stevia leaf extract and plaque pH was measured in situ at 4 time points (5, 10, 15, and 30 min)
after each rinse. After a washout period of 2 days, 10% sucrose and 1% Stevia product solutions
were similarly tested. Statistical analysis was performed using analysis of variance (ANOVA) test
and repeated measures ANOVA. Tukey’s HSD test was used to obtain multiple comparisons. The
level of significance was set to be at P < 0.05.
Results: At 5, 10, 15, and 30 min, a significant difference in mean plaque pH values was observed
between three test solutions (P < 0.000). Post hoc Tukey’s HSD test showed that the difference in
mean pH values between aqueous Stevia extract and sucrose and Stevia product and sucrose was
highly significant (P < 0.000).
Conclusion: Stevia leaf extract and commercially available Stevia product did not significantly affect
plaque pH values, implying that two solutions are non‑fermentable and do not support bacterial
survival.