Hydroxyapatite: Particularly recommended for older people and people with dry mouth

Introduction

Fluoride has been used in caries prophylaxis for many years, despite the occurrence of cosmetic problems, particularly in children, which can only be marginally resolved. These so-called "white spots" are also called fluorosis. As well as these undesirable side effects, it is also known that fluoride is not effective with dry mouth: Fluorides need saliva and the calcium and phosphate ions it contains to remineralize the enamel more quickly. Therefore, it is clear that a substance should be used in caries prophylaxis that is not only suitable for children, but is also effective without saliva. The solution to the problem is hydroxyapatite.

Question

How effective is hydroxyapatite at remineralizing carious lesions compared to fluoride?

Material and methods

This double-blind in situ study was conducted with 30 test subjects of different ethnic backgrounds. An enamel sample of extracted wisdom teeth that was prepared in advance and treated with acid was inserted intraorally into each test subject. The test subjects were provided with a total of three different toothpastes (5% hydroxyapatite, 10% hydroxyapatite, 1100 ppm fluoride). Each test subject used the same toothpaste for a period of 28 days. After a transition phase of 7 days without the inserted enamel sample but with a new toothpaste, the next toothpaste was tested over the same period of time. For each test toothpaste, the test subjects also wore a control (enamel sample not treated with acid). The mineral content of the enamel samples was calculated before and after the oral application using transverse microradiography (TMR). The values obtained were compared between and within the groups using statistical test procedures (corrected t-test etc.)

Results

All of the tested toothpastes showed a remineralizing effect. The differences between the groups were not significant.

Conclusion

Hydroxyapatite in toothpaste remineralizes the teeth just as effectively as a toothpaste with fluoride.
 

The publication of the study can be found here.

Source: Najibfard, K., K. Ramalingam, I. Chedjieu and B. T. Amaechi (2011). “Remineralization of early caries by a nano-hydroxyapatite dentifrice.” J. Clin. Dent. 22: 139-143.