Arginine-based prebiotic measures for caries prevention

Abstract

Dental caries, a chronic biofilm-mediated disease, is prevalent worldwide. Prevention of oral biofilm-related microbial dysbiosis would probably reduce this disease and its associated global burden. Fluorides (F) have been the mainstay for caries control for decades, inhibiting demineralization and facilitating remineralization. However, it has limited effect on oral biofilms. Wide spread use of F has developed F-resistant strains of S. mutans that further limits its effect on cariogenic biofilms. Prebiotics like arginine exhibits endogenous caries-protective benefits by restoring oral biofilm homeostasis. A novel integrated therapy, by combining the biofilm-modulatory effect of arginine with F, may have a synergistic effect for caries prevention; hence, a series of studies were undertaken to examine the caries-preventive potential of arginine in fluoridated vehicles or with F.

Eight studies were conducted based on findings from 5 systematically conducted reviews. A preliminary study evaluated the reliability of different methods for F detection in low F-containing child-formula dentifrices prior to examining the effect of L-arginine/ L-arginine monohydrochloride (Arg.HCl) on F bioavailability. Three studies comprehensively examined the caries-preventive potential of Arg.HCl in 1100-ppm and 600-ppm NaF dentifrices, respectively. The fifth study examined the effect of incorporating L-arginine/Arg.HCl in 5% NaF varnish on its physical-chemical properties, F/arginine release, remineralization potential and HGF-1 cytotoxicity. The effect of a novel synbiotic utilizing L-arginine and Lactobacillus rhamnosus GG on S. mutans was investigated in the sixth study. Further, the possibility of appending F to the synbiotic for developing synbiotic-F therapy was discerned in the seventh study. Finally, L-arginine was incorporated in glass ionomer cement (GIC) to evaluate the effect on its mechanical properties and antibacterial potential in the eighth study.

The first study showed that 2% arginine improved F bioavailability of the low F-containing child-formula dentifrices. The second and third studies concluded that incorporation of 2% Arg.HCl in 1100-ppm NaF toothpaste enhanced its caries remineralization potential on incipient caries-like lesions and its antimicrobial effect against S. mutans compared to 1100-ppm NaF toothpaste. The fourth study reported that 2% Arg.HCl enhanced the remineralization potential of 600-ppm NaF dentifrice, to a level comparable to 1100-ppm NaF dentifrice. The fifth study showed that incorporation of 2% L-arginine in 5% NaF varnish exhibited good biocompatibility, periodic perennial Arg/F release, with significantly higher F release and remineralization potential than 5% NaF varnish. The sixth study indicated that L-arginine enhanced the growth of L. rhamnosus GG and the combined synbiotic (2% L-arginine and L. rhamnosus GG) synergistically inhibited the growth of S. mutans. Further, the seventh study revealed that the combined synbiotic (2% L-arginine and L. rhamnosus GG) with 2000-ppm NaF provided optimum synbiotic-F synergism for restoring ecological homeostasis. Finally, the eighth study concluded that the addition of 4% L-arginine in GIC enhanced its antibacterial activity via a biofilm modulatory effect for bacterial homeostasis, with no detrimental effect on its mechanical properties.

In conclusion, adding arginine to fluoridated vehicles and probiotics (to develop as a synbiotics) appears a promising ecological-based caries preventive measure.