Dual Anti-Cariogenic Approach Through the Combination of Xylitol and Arginine

Objectives:

The objective of the study was to explore the potential of xylitol and arginine at creating a less cariogenic in vitro environment.
Methods:

The effect of varying concentrations of this sugar alcohol were evaluated on arginine metabolism, lactic acid generation, Streptococcus mutans growth, biofilm accretion, and pH drop reduction. S. mutans biofilm architecture was also evaluated by confocal laser scanning microscopy (CLSM), atomic force microscopy (AFM) and scanning electron microscopy (SEM). Neat solutions of xylitol and arginine, as well as dentifrice prototypes were tested.
Results: Arginine utilization was not significantly impacted by greater than or equal to 5% xylitol. All xylitol concentrations tested (1-10%) were able to significantly hinder S. mutans growth and to reduce S. mutans pH drop compared to the controls, but higher xylitol levels (5 and 10%) led to a more pronounced effect. At least 5% xylitol was necessary to inhibit S. mutans biofilm accumulation as quantified by crystal violet staining. A dentifrice containing 1.5% arginine and 5% xylitol showed a significant reduction in the acidogenic potential of salivary sediment samples over time, and saliva-derived in vitro biofilms treated with this dentifrice exhibited reduced lactic acid generation. Data collected by AFM and CSLM indicated arginine and xylitol causes distinctive biofilm architectural changes in S. mutans. Moreover, the combination of arginine and xylitol (adhesive force = 10.25 nN) resulted in a significant reduction in biofilm adhesiveness compared to arginine (adhesive force = 19.73 nN) alone rendering these biofilms less sticky. These findings were also confirmed by SEM.
Conclusions:

The combination of these two complementary oral care ingredients helps improve pH homeostasis. Xylitol targets glycolysis and decreases acid generation, while arginine’s catabolism leads to pH neutralization. Both ingredients also impact the stickiness of biofilms and offer a dual anti-cariogenic approach enhancing the already well established mode of action of arginine.