Don't brush your teeth, and you'll have a stinky mouth full of cavities -- but those aren't the only risks. They're not even the worst risks.

I've told you before how filthy yaws boost the risk of heart trouble. Now, new research confirms another big risk: People who don't brush are more likely to die of cancer.

The study of nearly 1,400 Swedes tracked for up to 24 years finds that those who died of cancer had consistently higher levels of oral plaque -- up to 40 percent more in some cases.

These weren't just the cancers that show up with old age, either. Based on life expectancies, those cancers cut 13 years off the lives of women and 8.5 years from men.

In other words, brushing your teeth could literally add years to your life.

But listen, you could brush twice a day, every day and still up your risk of deadly disease if you're using toothpastes loaded with chemical waste.

Fluoride, which is added to nearly every mainstream brand of toothpaste, can actually cause cancer -- specifically bone cancer, not to mention it's linked to any number of other diseases from Alzheimer's to osteoporosis.

Don't waste your money on expensive "all-natural" toothpaste, even if it is fluoride-free. Keep your teeth clean for pennies a day the Douglass way: Mix 3 percent hydrogen peroxide with baking soda until it a forms a paste, then work it into your gums with your fingertips -- you don't even need a toothbrush -- and rinse with the peroxide (just don't swallow it).

Be sure to floss and use a water irrigator between your teeth, and you'll have the strongest teeth, whitest smile, healthiest gums, and freshest breath around.