The pH of tooth-whitening products.
Level 5 - mechanism / opinion, no new human data
Bench laboratory testing of commercial products with no human clinical data
What was done
The pH of 26 commercially available tooth-whitening products was measured and compared across four categories: dentist-supervised home-bleaching products, over-the-counter whitening products, whitening toothpastes, and in-office bleaching products. Category differences were analyzed using one-way ANOVA and Least-Squares-Means tests.
What was found
Product pH ranged from 3.67 to 11.13 across all tested items. Dentist-supervised home-bleaching products averaged a pH of 6.48 (range 5.66 to 7.35), whitening toothpastes averaged 6.83 (range 4.22 to 8.35), and the 3 in-office bleaching products ranged from 3.67 to 6.53. Over-the-counter whitening products averaged a pH of 8.22 (range 5.09 to 11.13) and differed significantly from the other categories (p < 0.05). The most acidic product was Opalescence Xtra 35% hydrogen peroxide in-office bleach (pH 3.67), and the most basic was Natural White-Rapid White whitening gel (pH 11.13).
Why it matters
Whitening agents are placed in prolonged contact with oral tissues, so extreme deviations from neutral pH may increase the risk of enamel demineralization or soft tissue irritation.
Limits
This was an in vitro benchtop study and did not evaluate clinical biological effects such as enamel loss, tooth sensitivity, or mucosal irritation in human users. Product formulations tested reflect the commercial market in 2000 and sample numbers per subcategory were small.
Cited by
- contradicts Crest Whitestrips have an acidity level equivalent to battery acid.