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Sensitive Teeth

Dental Abrasion – Whitening Sensitive Teeth

Too Much Brushing Can Hurt You!

Have you ever looked at the ingredients on your toothpaste? Most toothpaste formulations are aimed at preventing tooth decay with fluoride. In an effort to have better plaque and stain removal toothpaste manufacturers add “mild” abrasives as inactive ingredients. The amount of abrasive varies between different brands and even among different formulations of the same brand. But how is one supposed to know how abrasive or gritty is your toothpaste and how much is too much?

The Relative Dentin Abrasivity Index (RDA) tells you just that. It goes from 0 or non-abrasive to 250 which is the maximum allowable grittiness by the American Dental Association.

It is important to know the RDA index of the toothpaste you use because too much abrasion can literally sand away particles of tooth structure every time you brush.

Considering that we spend close to 24 hours out of every year brushing our teeth (that is if you brush 2 minutes, twice a day) a low abrasivity index could mean the difference between clean teeth and worn-out enamel or root surfaces. Some of the worn areas of the tooth will need to be restored with fillings or in the worst cases need root canal and crowns – even if the tooth has never had a cavity.

This is a case where the medicine to prevent tooth damage could end up hurting you in other ways if not used adequately.

Here are the RDA values for common toothpastes:

To view a copy of this RDA list  click on the link below to view or print from Google Docs:

 RDA – Relative Dentin Abrasivity Index of Toothpaste Brands

Please feel free to ask Dr. Marin about Teeth Sensitivity problems by calling 626.810.5000 for more information.

* Toothpaste makers regularly measure their product’s abrasivity. It’s necessary for FDA approval, and usually is not included in marketing. Abrasivity measurements are given by what’s known as an RDA value which stands for radioactive dentin abrasion or relative dentin abrasivity.

To measure RDA in the lab, the tester starts with extracted human or cow teeth. The teeth are irradiated in a neutron flux, mounted in methylmethacrylate (bone glue), stripped of enamel, inserted into a brushing-machine, brushed by ADA standards (reference toothbrush, 150g pressure, 1500 strokes, 4-to-1 water-toothpaste slurry). The radioactivity of the rinsewater is then measured and recorded. For experimental control, the test is repeated with an ADA reference toothpaste made of calcium pryophosphate, with this measurement given a value of 100 to calibrate the relative scale.