Cavities between teeth (interproximal cavities) are a very significant problem in our sugar-laden culture. Liquids cause a lot of the trouble; watch out for how often you drink anything with sugar in it, especially drinks like Gatorade that advertise based on health concerns. More here:
The excellent DDSGP app for the iPad: (http://www.ddsgp.com/DDSGP/DDS_GP___Home.html)
-shows these types of cavities graphically very nicely:
Here, with my little arrows pointing to them, is the way two moderate-sized interproximal cavity look on an X-ray:
There are two "waves" of the darker areas that indicate decay, one in the outer enamel and one in the inner dentin.
Sometimes, we see shadows that are perhaps not what they seem. This X-ray hints at interproximal decay:
No cavity at all!
This presents a crushing diagnostic dilemma for us dentists, as the overlap and various distortions caused by imaging 3-dimensional objects onto 2-dimensional images can give us false positives.
Eventually, I am confident that 3-D imaging will become routine, de rigueur, au fait and, in fact, our raison d'etre when it comes to using X-rays to take pictures of teeth. (That last French word also happens to be, in my estimation, the very best of the many great beers created by the Dogfish Head brewing concern. "A deep mahogany ale brewed with Belgian beet sugars, green raisins, and a sense of purpose.")
Sorry. Got off track there. Here's the link to my thoughts on that:
The 3-D imaging, silly, not the beer!!!
We can also use tactile information (the oft-dreaded but really quite-innocent-if-used-properly dental explorer) and the new Soprolife optical detection unit to help us decide what's real and what's not:
Overall, this is a challenging area of dentistry, when the signal to noise ratio is right on the edge and things aren't so obvious. "Discretion is the better part of valor" and gaining more diagnostic information before touching a tooth with any kind of treatment is the best course of action when we feel we are being fooled by the very specialized kinds of information that X-rays can provide for us.