If you look at the label of a fluoridated toothpaste – Crest Cavity Protection, say – you’ll see just one active ingredient: fluoride. But you know it contains more than just that. What are those inactive ingredients all about?

That seems like a lot of inactivity… and it may be a little misleading. While none of those ingredients are active cavity-fighters, that doesn’t mean they don’t have any effect.

Consider sodium lauryl sulfate (SLS). This chemical is used in laundry detergents and other cleaning supplies. It also has some use as a pesticide. So what’s it doing in toothpaste? It’s a thickening agent and creates the sudsy feeling you get when you brush. It may also cause soft tissue damage and contribute to a range of systemic health issues, including cancer.

Note, too, that SLS is found in many more personal care products beyond toothpaste, from shampoo to facial cleansers to shaving cream.

Potential carcinogens may be found among the artificial flavors and dyes used to make conventional toothpastes. Blue 1, for instance, is among those substances “reasonably anticipated to be human carcinogens” by the American Cancer Society.

Toothpaste formulations differ, of course, from brand to brand, as well as among products produced under the same brand. Crest Pro-Health for Me, for instance, contains something Crest Cavity Protection does not: plastic – polyethylene (PE), to be exact. PE helps hold the toothpaste together, and it appears to get easily embedded in the gums. Dental hygienist Trish Walraven reports finding these small blue bits of plastic in her patients’ mouths every day and neatly explains why this is an issue:

Around our teeth we have these little channels in our gums, sort of like the cuticles around our fingernails. The gum channel is called a sulcus, and it’s where diseases like gingivitis get their start. A healthy sulcus is no deeper than about 3 millimeters, so when you have hundreds of pieces of plastic being scrubbed into your gums each day that are even smaller than a millimeter, many of them are getting trapped.

The thing about a sulcus is that it’s vulnerable. Your dental hygienist spends most of their time cleaning every sulcus in your mouth, because if the band of tissue around your tooth isn’t healthy, then you’re not healthy. You can start to see why having bits of plastic in your sulcus may be a real problem, sort of like when popcorn hulls find their way into these same areas. Ouch, right?

Other inactive ingredients to actively avoid include triclosan (a pesticide that disrupts hormones) and pyrophosphate compounds (causes skin irritation). You can learn more about such ingredients here and here.

So should you avoid toothpaste all together? Not necessarily. Although the mechanical action of brushing is the main thing that helps get the biofilm (plaque) off your teeth, toothpaste can make it easier by providing a bit of grit to the process. If you’re a DIYer, you can easily make your own healthy toothpaste at home, but there are plenty of alternatives available. Often, these products contain essential oils and other natural compounds known to control oral pathogens and support good gum health – lots of the good stuff, none of the bad.

Whichever you choose – or if you choose none at all – the main thing remains: Brush. Regularly. Correctly.

Note: This post was revised August 29, 2016.