Why do people get cavities?

I see people on a regular basis who have a large handful of small, superficial cavities that will require fillings.  These are new cavities that haven't been there long enough to cause major damage, cavities in patients who had their last checkup 1-2 years ago.  In these patients, my concern is not how big these cavities are, or where they are, or how to take care of them.  Rather, it is what? and why?  What is causing them?  Why is there a relatively recent occurrence of simultaneous decay?  

When I start questioning them I learn universally that they have a relatively new habit.  These include cough drops, sweet tea, coffee, and other sugared items.  They sip, snack, and suck on these little things throughout their day, giving themselves repeated small amounts of sugar a few times per hour.  Why does this cause decay?  

Decay is caused by bacteria, and bacteria are, as we all know, very small.  They don't require much food to replicate rapidly.  What they thrive on is frequency.  They need repeated feedings, irrespective of how large.  In fact, it would be better to quickly eat a 5 pound bag of sugar (at least for your teeth) than it would be to eat a teaspoon every half hour.  

Here's how this works: When you take something into your mouth that has nutritional value, it has nutritional value to the bacteria in your mouth as well.  Each time you eat or sip something, the bacteria of the mouth are fed.  These bacteria then do like every other living thing on this planet: they eat and then they release by-products.  In short, they eat and poop.  Those by-products are acidic.  This acid that is dumped onto the tooth causes surface damage in the form of demineralization, or breakdown of the mineral content of the tooth.  If the feeding frenzy ends and no more food is brought into the mouth, the saliva can repair and remineralize the tooth surface.

However, in the scenario we discussed earlier,  the patient is engaging in repeated small snacks and sips, the cycle of eating leading to acid by-product release occurs at each snack and/or sip and lasts 20-30 minutes each.  I think you might be seeing where this is going now.  These repeated acidity spikes in the mouth cause repeated damage to the teeth that can't be repaired by the saliva.  The tooth then begins to break down over time due to this acid bombardment.  

So, why do people get cavities?  It's due to concentration, not quantity.  It's the small snacks, that mug of coffee that sits on the desk all morning, and the gatorade bottle that starts the day full and ends empty that cause the decay.  We should all examine our diets and make sure that we aren't engaging in this behavior.  

Obviously, just eliminating one bad habit from your life may not be the cure-all.  You still need to brush and floss daily, use fluoride toothpaste, and visit your dentist regularly for cleanings and checkups.  Give that a try and let me know how it works for you!