Abrasion of human enamel by brushing with a commercial dentifrice containing hydroxyapatite crystals in vitro.
Level 5 - mechanism / opinion, no new human data
In vitro bench study on human enamel specimens
PubMed 10356789 · doi:10.1093/oxfordjournals.jmicro.a023663
What was done
Automatic toothbrushing was conducted in vitro for 10 minutes on polished tangential surfaces of sound human enamel using a commercial dentifrice containing hydroxyapatite (HAP), brushite (DCPD), and monetite (DCP) crystals, verified by X-ray diffraction. Treated surfaces were analyzed for abrasion and morphological changes using scanning electron microscopy and confocal scanning laser microscopy.
What was found
No numerical values or statistical metrics were reported in the abstract. Qualitatively, brushing with the HAP-containing dentifrice caused larger abrasive loss, greater surface roughness, visible bristle traces, and exposure of enamel prism structures compared to previously reported results from a dentifrice containing only DCPD.
Why it matters
It highlights that fine granular hydroxyapatite crystals in dentifrices can act as abrasive agents on sound enamel rather than simply occluding early caries defects in laboratory conditions.
Limits
The study was conducted strictly in vitro and lacked normal oral physiological factors such as the acquired salivary pellicle and natural remineralization cycles. The abstract does not provide the sample size (n), quantitative measurements of wear depth or roughness, or statistical comparisons, and it relies on historical comparisons to previously published work for the control formulation.
Cited by
- context Tooth enamel has a hardness of 5 and is harder than steel.