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RDA – dentin abrasion

17 June 2017

Every single one of us would love to show off their smile straight out of the Hollywood catwalks. Charming our friends with a pure whiteness of our teeth has a steep price though – whitening at the dental office is a very expensive luxury. That’s why so many people decide to buy a whitening toothpaste, thinking: “Even if it won’t help me in the end, it doesn’t hurt to try!” Unfortunately, it’s not exactly true.

What’s in the toothpaste?

The main function of a tootphaste is cleaning our mouth. Because of that, there are many products avaible on the market which are only different from one another in taste and packaging. Most of them contain water, fragrances, preservatives, foaming agents and active substances such as the herbal extracts, fluoride salts, aminofluorides and hyaluronic acid. Between 20 to 40 percent (in some extreme cases, even somewhere around 60%) of the toothpaste consists of abrasives, which mechanically remove the dental plaque, residue and superficial discolorations. It’s the significant amount of abrasives which makes the whitening effects promised by the manufacturers possible. The RDA term is tied to the amount of abrasives contained within a toothpaste.

RDA value

RDA (Radioactive Dentin Abrasion) is a dentin abrasion ratio. It’s being laboratory measured for every toothpaste. In order to measure its value, a method involving rubbing the dentin off using the irradiated toothpaste containing radioactive phosphorus; the more dentin gets rubbed off, the higher the RDA value.

The most frequently used abrasives are: polymethyl, calcium hydroxide, magnesium hydroxide, calcium carbonate and silicon oxide. In order to work optimally, these abrasive particles should be round in shape and 10 micrometers big.

Which RDA level is safe to me?

Using a toothpaste with carefully chosen RDA value is essential for taking care of our teeth properly. If dentin abrasion is too intense, it might lead to sensitive teeth, along with making them more susceptible to the cavities.

The safe RDA level has been characterized by the American Dental Association to be between 0 to 250 RDA. The value closest to the highest of these levels is usually contained within the products adressed towards chain smokers and whitening toothpastes. Because of the possibility of dentin damages, such products shouldn’t be in use for longer than 2 – 3 months, as recommended by the manufacturers.

Despite of such wide scale introduced by the American Dental Association, the dentists recommend to use the toothpastes with RDA levels which don’t exceed 50 – 80 when it comes to daily bushing.

In case of the sensitive teeth, the RDA value should be somewhere around 30 – 70.

Before you’ll decide whether it’s worth using a toothpaste to remove discolorations caused by coffee, tea or cigarettes, you should think it over, ask yourself if it won’t hurt you more than help you. And if you’ll decide to use a toothpaste with high RDA value, be smart about it and remember to consult your dentist.