How Hydroxyapatite Helps Rebuild Tooth Enamel
Toothpastes that contain hydroxyapatite can help remineralize the enamel, reducing the risk of cavities and erosion. Although you might not easily find a toothpaste that contains hydroxyapatite or calcium phosphate on the shelf at a drugstore, there have been multiple studies that examine the effect the ingredient has on the tooth enamel.
One study, published in the Journal of Dental Research, Dental Clinics, Dental Prospects, looked at the effect hydroxyapatite toothpaste had on a group of 80 extracted teeth. Forty teeth were brushed with an ordinary fluoride toothpaste and 40 were brushed with a toothpaste containing both fluoride and nano-hydroxyapatite (nano- means the particles of hydroxyapatite were extremely small). All the teeth were demineralized using an acid solution, then brushed twice daily with one of the two toothpastes for 15 days. The teeth that were brushed with the nano-hydroxyapatite-containing toothpaste were considerably harder (remineralized) at the end of the study compared to those brushed with toothpaste containing only fluoride.
Another study published in the Korean Journal of Materials Research examined the effect that toothpaste containing a variety of concentrations of hydroxyapatite could have on teeth. Researchers created multiple kinds of toothpaste with concentrations of hydroxyapatite ranging from 0 to 15 percent. The toothpaste samples were then applied to extracted human teeth that had been drilled to create artificial cavities. After seven days of cycling between a demineralizing acid solution, a remineralizing solution and brushing treatment, the teeth brushed with the toothpaste that contained the highest concentration of hydroxyapatite showed the most improvement in the strength of the enamel (remineralized) and the lessen the depth of the cavities.