Influence of Dentifrices pH on Enamel Microhardness In Vitro.
Level 5 - mechanism / opinion, no new human data
In vitro laboratory study on enamel slabs without human clinical data
What was done
Twenty-eight enamel slabs were divided into seven groups (n = 4 per group) to evaluate the effect of dentifrice pH on enamel remineralization. Six fluoride toothpastes and one non-fluoride control toothpaste were applied during a 12-day daily cycling regimen involving brushing, demineralization, and remineralization in artificial saliva. Dentifrice pH was measured in a 1:3 deionized water slurry. Surface microhardness was assessed at baseline and after 12 days using mean Vickers hardness numbers from six indentations per slab and analyzed via Student's t-test and one-way ANOVA.
What was found
All fluoride toothpaste groups showed higher surface microhardness compared to the non-fluoride control group. Toothpastes with lower pH (Pronamel, Sensodyne F, Sensodyne Rapid) demonstrated statistically superior surface microhardness compared to the other fluoride dentifrices and control after 12 days (p < 0.001). Specific numerical values for microhardness and pH were not reported in the abstract.
Why it matters
The study suggests that slightly acidified fluoride toothpastes may enhance enamel surface remineralization more effectively than neutral or higher-pH fluoride formulations.
Limits
This was an in vitro bench model using artificial saliva, which lacks the biological complexity of the oral cavity (such as natural pellicle formation, bacterial dynamics, and salivary flow). The sample size was very small (n = 4 slabs per group), testing was limited to 12 days, and exact numerical values for pH and microhardness were omitted from the abstract.
Cited by
- supports Acidifying the mouth enhances the remineralization capacity of fluoride.