Streptococcus mutans and Caries: A Systematic Review and Meta-Analysis

Area of Science:

• Microbiology
• Dental Research
• Oral Health

Background:

• The role of *Streptococcus mutans* as the primary cause of dental caries has been debated due to reliance on single-species identification.
• Previous studies often overlooked the comprehensive oral microbiome composition, limiting understanding of *S. mutans*'s etiological significance.

Purpose of the Study:

• To systematically review and assess the prevalence and abundance of *S. mutans* in caries-active (CA) versus caries-free (CF) subjects.
• To analyze clinical studies that investigated the oral microbiome, focusing on *S. mutans* detection alongside the broader microbial community.

Main Methods:

• A systematic literature search was conducted across PubMed, Cochrane, and Embase databases up to May 22, 2023.
• Included studies analyzed both *S. mutans* and the oral microbial community in CA and CF individuals using DNA-based methods.
• Data on prevalence and relative abundance were extracted and analyzed using a random-effects model meta-analysis.

Main Results:

• Of 19 eligible studies, 16 reported higher *S. mutans* prevalence in CA subjects compared to CF.
• All 11 studies reporting relative abundance showed higher levels of *S. mutans* in CA individuals, ranging from 0.001% to 5%.
• Microbiome data analysis did not identify other bacterial genera or species as consistently associated with caries.

Conclusions:

• This microbiome-based evidence strongly associates the prevalence and abundance of *S. mutans* with caries experience.
• The findings support the recognition of *S. mutans*'s cariogenic role within the oral ecosystem.
• Further research is warranted to fully elucidate the specific mechanisms and functions of *S. mutans* in dental caries development.