11/21/2024
How do hydroxyapatite and fluoride work? Do we want them in our toothpaste?
Chrissy Harlow, BSDH, RDH
Hydroxyapatite works by preventing or reducing demineralization.3 Nanohydroxyapatite is becoming popular as an alternative to fluoride toothpaste for people who want to use less fluoride. Nanohydroxyapatite acts as a remineralizing agent, reducing dentinal hypersensitivity and aiding in bone regeneration.4
Nanoydroxyapatite Controversy – Banned in Europe
There’s some controversy around nanohydroxyapatite involving concerns that the nanoparticles may pe*****te the skin and affect organs. While there’s no evidence supporting these claims, the European Union has prohibited the use of nanohydroxyapatite in cosmetics and toothpaste.5 Neither nanohydroxyapatite nor hydroxyapatite have been approved by the FDA.
Fluoride has been celebrated as one of the great achievements in public health in the 20th century.6 It’s a naturally occurring substance that reduces enamel demineralization caused by plaque acid, aids in remineralizing early cavities, and inhibits bacteria. Fluoride also helps transfer calcium and phosphate ions into the enamel, making it more acid-resistant.
Fluoride Controversy – California Case
Although fluoride can be toxic at high concentrations, everyday use in drinking water and dental products such as toothpaste and mouthwash is unlikely to cause toxicity.7 Some studies have assessed fluoride's potential impact on neurology and bone growth, but no evidence has conclusively linked it to these issues.7 Fluoride is FDA-approved as a class II medical device for cavity liners and tooth desensitization.
On September 24, 2024, a federal court in California ruled that the Environmental Protection Agency (EPA) must strengthen regulations on fluoride in drinking water:
Decision
The court ruled that the levels of fluoride in drinking water in the United States pose an unreasonable risk to public health. The court ordered the EPA to act to strengthen regulations.
Explanation
The court found that the plaintiffs had adequately demonstrated an “unreasonable risk” of harm. However, the court did not conclude with certainty that fluoridated water is injurious to public health.
Impact
The American Academy of Pediatrics (AAP) and the American Dental Association (ADA) have both stood by their fluoride recommendations following the ruling.
Extensive research has been conducted on many dental products, generating much speculation about their benefits and drawbacks. Fluoride has been widely accessible and used in the dental industry for many years and has proven to be effective. These ingredients have beneficial properties and can be used to help prevent dental caries, but more research is needed on hydroxyapatite products in dentistry.
When deciding which type of cavity prevention you want to recommend in a toothpaste or rinse, consider the patient's needs. If a patient already has decalcification of the enamel and wants to prevent future decay, a product with hydroxyapatite can help. If the patient is cavity-prone, fluoride has been proven to help with cavity prevention.
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References
1. Loimaranta V, Mazurel D, Deng D, Söderling E. Xylitol and erythritol inhibit real-time biofilm formation of Streptococcus mutans. BMC Microbiolhello. 2020;20(1):184. doi:10.1186/s12866-020-01867-8
2. Riley P, Moore D, Ahmed F, Sharif MO, Worthington HV. Xylitol-containing products for preventing dental caries in children and adults. Cochrane Database Syst Rev. 2015;2015(3): doi:10.1002/14651858
3. O'Hagan-Wong K, Enax J, Meyer F, Ganss B. The use of hydroxyapatite toothpaste to prevent dental caries. Odontology. 2022;110(2):223-230. doi:10.1007/s10266-021-00675-4
4. Bordea IR, Candrea S, Alexescu GT, et al. Nano-hydroxyapatite use in dentistry: a systematic review, Drug Metab Rev. 2020;52:2:319-332. doi:10.1080/03602532.2020.1758713
5. Opinion on hydroxyapatite (nano). Regulatory toxicology and pharmacology. 2018;98:274-275. https://doi.org/10.1016/j.yrtph.2018.07.018
6. Murthy VH. Surgeon General's Perspectives. Public Health Rep. 201;130(4):296-298. doi:10.1177/003335491513000402
7. Arifa MK, Ephraim R, Rajamani T. Recent advances in dental hard tissue remineralization: a review of literature. Int J Clin Pediatr Dent. 2019;12(2):139-144. doi:10.5005/jp-journals-10005-1603
8. Meshki R, Basir L, Rahbar N, Kazempour M. Comparison of the effect of fluoride gel and two toothpastes with different materials on remineralization of initial carious lesions in primary teeth. J Family Med Prim Care. 2021;10(9):3309-3313. doi:10.4103/jfmpc.jfmpc_1046_21
