Exploring the Benefits of Hydroxyapatite in Toothpaste
Image: katifinell/stock.adobe.com
People looking for an alternative to fluoride toothpaste don’t have to miss out on its protective, anti-cavity effects. Hydroxyapatite is gaining popularity as a toothpaste ingredient thanks to its ability to remineralize teeth and protect against cavities—plus it’s proving to have a few added benefits as well. But as with any “new” ingredient, many people have questions about just what hydroxyapatite is, how it works, and whether it’s safe.
As a biomaterials company, Himed has been working with hydroxyapatite for thirty years. So we wanted to share a quick guide to this compound—and explain why it’s a great ingredient in your next tube of toothpaste.
What is hydroxyapatite?
Hydroxyapatite (HA) is a calcium phosphate compound that’s very similar to the makeup of human bones and teeth. In fact, it’s the main inorganic compound found in tooth enamel. Produced in a lab, HA is used in many medical and dental applications, such as bone grafting material and as a coating for orthopedic and dental implants.
The calcium phosphate hydroxyapatite can be manufactured in a powdered form or cast into shapes such as cubes and spheres. When used as an additive in toothpastes, very fine powders are preferred, but under a powerful scanning electron microscope the granular nature of even the finest powders becomes clearly evident.
Not only is HA extremely similar to bone, its structure and chemical makeup are bioactive, meaning they interact with nearby cells, encouraging bone regrowth. In the case of a bone graft, bone tissue regrows on the scaffolding of HA, eventually replacing the bone graft with new bone. When an implant is coated with HA, the surrounding bone is encouraged to form a secure bond with the implant by integrating the implant via new cell growth.
How does hydroxyapatite in toothpaste work?
Caries (tooth decay) happens when bacteria in your mouth consumes sugars and other carbohydrates, lowering the pH levels to create an acidic environment. Positively charged hydrogen ions then bind with calcium and phosphate ions from your teeth, resulting in the demineralization of your tooth enamel.
In toothpaste, the nano form of hydroxyapatite is generally used. These small nanocrystals offer a large surface area for proteins to bind, which means they are able to bond with plaque and bacteria, so they can be easily rinsed away. Even more critically, hydroxyapatite works to remineralize the surface of your teeth by introducing readily available calcium and phosphate.
Because the HA particles mimic the properties of tooth enamel, they are able to penetrate the voids left by demineralization, bind to the enamel, and effectively build back up the surface of the tooth. When small lesions in the tooth are repaired in this way, the process towards developing cavities and more severe tooth decay is effectively stopped.
Hydroxyapatite vs fluoride
Fluoride has long been a key ingredient in anti-cavity toothpaste. Like hydroxyapatite, it also works to remineralize and strengthen tooth enamel and protect from tooth decay. But the use of fluoride is not without its concerns. Aside from toxicity risks, fluoride is limited in the amount of calcium and phosphate it can supply to teeth as it relies on the calcium and phosphate present in your saliva. HA on the other hand, is made from those exact elements, so they’re readily available.
In 2021, researchers from the University of Toronto produced a research review in Odontology showing that hydroxyapatite toothpaste not only helped remineralize teeth as effectively as fluoride, it appeared to help with other dental concerns as well. Where fluoride itself offers no whitening properties, HA toothpaste produced whitening and brightening effects. HA toothpaste also demonstrated an ability to help lessen the effects of dentin hypersensitivity, a common concern that brings many patients to the dentist’s chair.
Is hydroxyapatite toothpaste safer than fluoride toothpaste?
Many toxicity concerns surrounding fluoride focus on small children, who are more likely to swallow fluoride toothpaste, which can result in intestinal distress. In sufficiently high levels (not typically those found in toothpaste) excess fluoride in the body can lead to negative effects on the liver, thyroid, bones, and perhaps surprisingly, in teeth as well.
Patches of white discoloration on tooth enamel indicate a mild form of dental fluorosis, caused by an excess of fluoride coming into contact with tooth enamel. Image by Matthew Ferguson 57 via Wikimedia Commons, licensed under the Creative Commons Attribution-Share Alike 4.0 International license.
As for hydroxyapatite, it has been used for decades in implant and dental devices. Its usage in oral care is relatively new, but recent studies have found very low health risks associated with HA when it is used in oral care products, or even when chronically ingested. This also means that, unlike fluoride, the dosage of HA within a given toothpaste can be increased. Dentists can prescribe toothpastes with high concentrations of HA to help address a patient’s demineralization issues.
Can I buy hydroxyapatite toothpaste?
While it may be tougher to find in stores, you can easily buy hydroxyapatite toothpaste online. This article offers a hands-on review of six popular brands; you may find one you like there. Hydroxyapatite can also be found in mouthwashes, tooth gels, and even tube-free tooth powders and tablets.
As suppliers of biomaterials like hydroxyapatite, we here at Himed are excited to see HA contributing to an effective and safe application that can help people have brighter and healthier teeth.