A recent study by the University of Illinois found that the saliva of babies contains high amounts of bacteria that cause early childhood caries (ECC) [source: Swanson]. If you remember in the first section, caries is actually an infectious disease that causes tooth decay. It was originally thought that dental care should be introduced around 19 months of age, but this research confirms that dental care should begin long before a child even has teeth.
Older people also run the risk of developing cavities for a number of reasons. There was a time when extracting a tooth was the preferred means to get rid of a cavity. But today there are better options including root canals and crowns that let people keep their original teeth much longer. But because most people will experience some degree of gum diseases, the soft tissue of the mouth can recess over time and expose more of the teeth to bacteria. Another risk factor more prevalent among seniors is the lack of saliva, which contains fluids that neutralize acids and helps clear away food remnants. But many medications on the market for high blood pressure, inflammation and heart disease actually reduce saliva flow, taking away one of our best weapons against cavities [source: AGS].
Brushing and flossing regularly are still the best one-two punch we have, but we can supplement this by being mindful of what we put in our mouths.
So put down the soda. And please -- do not use your teeth to open that bag of chips.