Tooth enamel is the hardest and most highly mineralized substance in the human body. Enamel’s primary mineral is hydroxyapatite, which is a crystalline calcium phosphate. The large amount of this mineral in enamel accounts for its strength.
In considering whether to whiten one’s teeth, a common concern that I hear from my patients is, “Does the whitening process damage the enamel surface?” A study published in the June 2012 edition of the Journal of the American Dental Association shows that bleaching gels do not alter the calcium and phosphorus concentrations on the enamel surface.
The researchers used a variety of professional whitening materials with concentrations as low as 10% and as high as 38% in-office hydrogen peroxide. They evaluated the teeth before the whitening treatment and then during the whitening treatment at 7, 14 and 21 days. Finally, they evaluated the teeth after the whitening treatment at 7 and 14 days. Regardless of the concentration of whitening agent used, there were no differences among calcium and phosphorus concentrations at the various evaluation times.
The researchers believe that saliva plays an important role in protecting the teeth. In other words, while there may be a temporary loss of minerals in the outer enamel, this effect is quickly reversed by minerals found in saliva.
Incidentally, different professional whitening techniques also did not alter the mineral content in teeth.
However, there is a very important point to consider. This research involved only professional whitening agents that are approved by the American Dental Association. If you are considering an over-the-counter teeth whitening agent, and especially those purchased over the internet, buyer beware!
I have recently read reports out of England where, as in the US, non-dentists are providing teeth whitening services. In order to bypass legislation in England, health spas and beauty spas on cruise liners are using chlorine dioxide to whiten teeth.
In low concentrations, chlorine dioxide may be effective in whitening teeth. However, many of the chlorine dioxide gels are too acidic. As a result, teeth are becoming permanently etched and damaged and appear to lose their luster or shine. The teeth may also feel rough. As a result, while the teeth initially appear whiter, they will also quickly pick up stain and become discolored. The subsequent repair costs can be significant.
The bottom line is this: If you are considering teeth whitening, it is best to first consult your dentist. In our office, we use professional whitening products approved by the FDA and the American Dental Association (ADA). When properly used, these products are safe and effective.
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