Changes in oral microbiome in preschool children after using toothpaste with different fluoride concentrations

Dental caries is a multifactorial disease primarily driven by an imbalanced oral microbiome, with cariogenic bacteria in dental plaque playing a central role. Fluoride-containing toothpaste is commonly used for caries prevention, but its effects on the oral microbiome, particularly at different fluoride concentrations, remain unclear. This study aimed to assess the short-term impact of fluoride toothpaste with different fluoride concentrations (standard fluoride 1000 ppm, low fluoride 500 ppm, and non-fluoride) on the oral microbial community in preschool children.

A total of 48 children participated, with dental plaque samples collected at baseline, and at 1-week and 4-week follow-up after using the assigned toothpaste. The microbial community was analyzed using 16S rDNA sequencing to evaluate diversity, composition and shifts in bacterial populations.

The results showed no significant differences in alpha diversity indices (Chao1, Shannon, Simpson, etc.) between pre- and post-intervention samples in all groups, indicating overall microbial stability. However, beta diversity analysis revealed significant differences in microbial composition between the fluoride and non-fluoride groups. Notably, the standard fluoride group exhibited a more substantial shift in bacterial structure, with an increase in the abundance of beneficial species such as Streptococcus parasanguinis and Veillonella, and a reduction in genus, such as Haemophilus and Neisseria, which are associated with biofilm formation and may affect the colonization of cariogenic bacteria.

These findings suggest that fluoride-containing toothpaste, especially standard fluoride (1000 ppm) toothpaste, can modulate the oral microbiome by decreasing harmful bacteria and promoting a more balanced microbial environment, potentially reducing the risk of dental caries in preschool children.

This study demonstrates that standard fluoride (1000 ppm) toothpaste effectively shifts the oral microbiome in preschool children by reducing harmful bacteria (e.g., Haemophilus) while enriching beneficial species (e.g., Streptococcus parasanguinis). These findings suggest a potential role for fluoride toothpaste in caries prevention by promoting a healthier microbial balance, offering supportive evidence for its use in evidence-based pediatric dental care.