Things I know for sure ... maybe

Dental school professor pokes fun at the evolution of dental science. What do we tell our students anyway?

Dec 28th, 2009

By Robert J. Weyant, DMD, DrPH

Fluoride works primarily through a systemic effect. Everyone knows that. Wait; no it doesn't. It's mostly topical; I saw some research. Wait! It does have a large systemic effect, I learned from some more research. Is that the only effect? No. Is it the major one? Oh my, maybe it's both. Which effect is bigger? Does it vary by age? Who knows? Now what do I tell my students?

Well, at least I know that diet is of huge importance in controlling caries. I will tell them that. And food consistency is important — sticky is bad. No, soda pop is bad — but it's not sticky. Well, then it's actually frequency. No, there's no association with frequency, I saw it in some research. Then it must be total intake. But in the U.S., sugar consumption continues to go up and caries down. Wait. We are all well over the cariogenic threshold, so it doesn't matter. Even if it does, people won't be convinced to change their diets. Better skip that lecture too.

Remember the answer to the old question, "Do I have to floss all my teeth?" "No, just the ones you want to keep." But flossing isn't associated with caries is it? Can I say that out loud? It just helps with gingivitis, which isn't really associated with periodontal disease anymore, either, right?

But you better get your teeth cleaned regularly or you'll get periodontal disease, or maybe not. Well, at least we know that periodontal disease causes heart disease, preterm birth, and diabetes. So let's treat the perio and cure the other disease. That seems simple. What do you mean the other diseases don't change when you treat the perio? That doesn't make sense. Oh my, it's so confusing! Mum's the word.

Well, perhaps I should just stick with the truism that everyone should brush for three minutes and use the proper technique and the right brush, because all plaque has to be removed to prevent decay. What do you mean you can't remove all the plaque with a brush? Say what? Not all plaque is bad? Can that be? Some people have lots of plaque and no disease? Whoa there! It's the fluoride that does the trick. So don't worry about brushing technique — just get the fluoride in there. Does that sound right? So confusing. But is it the topical effect or the systemic? I think I'm back where I started. I still don't know anything. What are my students to do?

I know. I'll tell them to send all their patients to have their third molars out. Those things are always trouble.

Robert J. Weyant, DMD, DrPH, is with the Department of Dental Public Health, School of Dental Medicine, University of Pittsburgh.

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