Removal of Extrinsic Stains
Removal of extrinsic stained components can be accomplished through the use of an abrasive or through the use of chemical agents such as chelants and peroxides. Though not the primary focus of this review, we discuss it briefly here. The removal of stained components is restricted to stains on the tooth surfaces. Abrasives mechanically remove stains from the tooth surface through a polishing action.17-21 The key to this technology is finding materials which can effectively remove stain and not cause wear damage to the teeth – particularly to exposed dentin. This is managed through established safety standards developed in the industry with the ADA and FDA for over 40 years.22 Products with a relative dentin abrasions (RDA) score of 250 or less are considered safe for use for a lifetime by the ADA.
Other technologies to mitigate extrinsic stain are chelant technologies. These ingredients function by disrupting the connection between the stain and the tooth surface. For simplicity, tooth surface here includes the acquired pellicle.23-25 An advantage of this technology is that because they work with chemical action, they can also reduce stains from non-brushed as well as brushed areas.
The efficacy of both abrasives and chelants are limited to surface or extrinsic stains. As a result, their effects on overall whitening of teeth are quite different. Extrinsic stains often accumulate along the margin, while intrinsic stains tend to cover the entire tooth. Extrinsic stain removal products are highly useful in maintaining tooth whiteness between dental cleanings, or after oxidative bleaching.26 Stain prevention can be reasoned to be particularly important following oxidative bleaching since whiter teeth may visually show extrinsic staining more acutely.