Streptococcus dentisani as an oral probiotic: a systematic review of clinical evidence on the pH modulation and microbiota shifts.

BACKGROUND

Dental caries prevention can be approached through ecological modulation of the oral biofilm. Among oral probiotics, Streptococcus dentisani stands out for its arginine deiminase (ADI) pathway, producing ammonia with an alkalinizing effect, and for bacteriocins active against cariogenic organisms, suggesting restoration of acid-base homeostasis and displacement of dysbiosis-associated taxa.

OBJECTIVE

To systematically review clinical evidence on S. dentisani and other probiotics regarding their effects on pH modulation and oral microbiota shifts.

METHODS

A PRISMA-guided systematic review of PubMed, Scopus, and Web of Science was conducted, including randomized controlled trials (RCTs) and observational studies reporting at least one prespecified outcome (pH or microbiota).

RESULTS

Two clinical studies specifically assessed S. dentisani, reporting transient oral colonization, increased salivary alkalinity, and reductions in S. mutans, with one trial documenting a favorable community shift by 16S sequencing. Across the remaining studies, which mainly involved Lactobacillus and Bifidobacterium strains, nine reported reductions in cariogenic markers and five reported increases in pH/buffering capacity; these findings do not pertain to S. dentisani but to other probiotic strains. Caries incidence was evaluated only in lactic probiotic trials with mixed findings; no caries-incidence data were available for S. dentisani.

CONCLUSIONS

S. dentisani demonstrates consistent mechanistic benefits-pH increase and modulation of the oral microbiota-supporting its candidacy as an oral probiotic. Evidence on caries prevention remains insufficient, underscoring the need for longer, standardized trials incorporating clinical endpoints and microbiological profiling.