Summary
This in vitro diagnostic accuracy study evaluated the antimicrobial efficacy of nano-hydroxyapatite (nHAP) toothpaste against oral bacteria (Porphyromonas gingivalis and Streptococcus mutans) in a dual-species plaque biofilm model on human enamel-dentin discs. Four treatment groups (nHAP toothpaste, fluoride toothpaste, domiphen toothpaste, and water control) were compared using colony forming unit counting, scanning electron microscopy, and confocal laser scanning microscopy. The nHAP group showed the greatest bacterial reduction and the strongest resistance to acidification of the culture medium over 96 hours. This study does not measure heavy-metal contamination in toothpastes; it evaluates antimicrobial activity of a specific formulation type. It has no primary metals occurrence data relevant to the Toothpaste (Cat 2) page’s contamination profile.
Evidence Fitness
Context only. This source contains no heavy-metal concentration data. It evaluates the antibacterial mechanism of nHAP toothpaste rather than heavy-metal content. It does not contribute to the metals evidence tables on Toothpaste (Cat 2).
Methods (brief)
In vitro biofilm model on enamel-dentin discs cut from impacted human molars (ethics: Jiangsu Province Engineering Research Center of Traditional Translational Medicine, approval P2024-144-001). Dual-species biofilm of P. gingivalis and S. mutans cultured on enamel-dentin discs for 96 hours in BHI liquid medium. Discs exposed to toothpaste solution twice daily; culture medium pH monitored at 24, 32, 48, 56, 72, 80, 96 hours. Outcomes: biofilm acidogenicity (pH), bacterial viability (CFU counting), biofilm morphology (SEM), bacterial spatial distribution (CLSM with SYTO-9 and propidium iodide live/dead staining). Statistical analysis: one-way ANOVA with Tukey post-hoc.
Implications
- Certification: No contribution to metals occurrence data or threshold work.
- Courses: May be useful as background on nHAP toothpaste formulation mechanisms in an oral health module.
- App: Not applicable.
Related evidence
None — this source does not carry metals contamination data applicable to any wiki metals or ingredient page.
Update history
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