Although the ingredients, and their proportions, of many toothpastes are closely guarded secrets, most toothpastes ( including therapeutic pastes) contain all or some of the following substances:Abrading, polishing, and bleaching agents. Abrading and polishing agents comprise as much as 50% of most dentifrices. The abrasive ingredient actually grinds off enamel and dentin, much like rough sandpaper abrades wood. The polishing agents are included to help smooth off the roughened areas, like using a fine sandpaper. The extent to which any dentifrice will abrade your teeth will depend on the following factors:
- Its abrasive index
- Its acidity
- The hardness of your tooth enamel
- The hardness of the toothbrush bristles
- The force with which you use your brush
- How long and how often you brush
Thus, you could use an abrasive toothpaste but not brush very hard or very often and therefore not wear away as much tooth as if you used a less abrasive paste, used hard bristles, brushed hard, and brushed often.
Abrading and polishing agents can be valuable if they are used correctly. But toothpastes that are highly acidic or abrasive can be double-edged swords if they are abused. Originally intended to remove dietary and other stains, such as those caused by coffee, tea, and tobacco, some of these pates contain acids that are actually powerful enough to remove tooth enamel and dentin. This is especially true if you have soft teeth.
You may not know it, but although enamel is pretty hard and looks solid white, it is actually somewhat translucent. The dentin, the supportive tooth substance that lies directly underneath the enamel, is yellow in color. As the enamel wears away and gets thinner, the dentin shows through more and more. And because the dentin is yellow, guess what seems to be happening to your teeth? Yep, they will appear to be yellowing. Although enamel can be intrinsically stained during its formation and varies in color, the truth is that, once it has formed, the enamel itself never actually becomes yellow, it just becomes thinner, pitted, or stained. If the enamel is intrinsically stained, or if it has been getting thinner, using strong abrasive or etching agent defeats the whole purpose of the whiter-and-brighter promotion.
Many people are born with yellow-looking teeth. This could be the result of thinner, colored, or more translucent enamel or of dentin that is more yellow than normal. If you find yourself in this category, don’t fall into the whitener paste trap. When you first use such pastes periodically to remove dietary stains and then stop, you will be using them correctly. But if the continual search for those movie-star whites has led you to think that scrubbing and polishing your enamel away is the right way to go, you are barking up the wrong tree.