Toothpaste and the dangerous abrasive effect
Cleaning particles are an important component of toothpastes. These abrasives, as they are known, mechanically remove dental plaque. Nevertheless, the paste should not be too strongly abrasive. Over the years the abrasion can cause damage to the tooth enamel, which does not regenerate itself. This damage is more visible and pronounced in the soft dentin. The German Dental Association recommends that people choose less abrasive toothpaste if the necks of their teeth are exposed.
The abrasive effect of a particular toothpaste on tooth dentin depends on the hardness, amount and particle size of the abrasive additives it contains, such as silica or alumina. Abrasivity is measured as the RDA value (radioactive dentin abrasion), ranging from 30 to over 200. This value is determined via a complex process that involves testers brushing over radioactively marked dentin samples. The abraded material is then measured via the resultant radiation intensity of the toothpaste slurry. Not all experts agree on the validity of RDA values, as test results have been known to vary partly from lab to lab.