The pursuit of whiter teeth is a $1.4 billion-a-year industry, and it shows no signs of slowing down. With so many options out there promising a glowing smile, it’s hard to know what really works and what doesn’t. But studies have shown that some ingredients common in whitening toothpastes may be doing the latter - that is, staining your teeth while promising to whiten them.
"The ingredients that are causing all the problems are CPC and something called stannous fluoride that helps to rebuild enamel," explains Dr. Stephen Hill, a dentist in Allen, Texas.
According to Hill, CPC, or cetylpyridinium chloride, is an antibacterial agent added to many toothpastes to kill oral bacteria. But it quite literally has a dark side, because it also has been known to cause the dead bacteria to cling to your teeth along the gum line, leaving behind unsightly brown stains.
"So, you’ve gone through all the trouble of killing these bad bacteria, only to have them leave a crime scene on your teeth," Hill says.
Stannous fluoride, on the other hand, is added to help rebuild enamel and strengthen the teeth. Unfortunately, it too has a dark side: tin.
"One of the chemicals that make up stannous fluoride molecules is tin," Hill says. "If you look at a tin roof or a piece of tin, it’s not white, it’s silver. So, as you’re rebuilding your enamel with stannous fluoride, you’re rebuilding it with little bits of silver-colored metal, which can sometimes cause discoloration."
If you’re concerned that your toothpaste may contain CPC or stannous fluoride, check the label. Most pastes have stopped using CPC, but those that still do bear a warning label. As for stannous fluoride, it is a bit more common but also easy to locate on most toothpaste ingredient labels. Thankfully, according to Hill, it’s also not as likely to stain.
"Just be aware of your teeth, and what foods you eat, and if your teeth seem to be darker than they should be, you might want to see if your paste has stannous fluoride. Otherwise, I wouldn’t worry too much about it," Hill says. "The benefits usually outweigh the negatives."