The Theory: How Oral Disease Might Cause Cancer

Science doesn't know how oral disease is related to cancer. But we've seen enough math over the past decade or so of study to know that there's definitely something going on in your mouth that can make you vulnerable to cancer -- even decades later. We're going to lay out the most commonly-accepted theory for you.

The Inflammation Theory

The mouth is a place of almost constant microscopic injuries. For example, something as simple as eating popcorn can cause hundreds of tiny scrapes and cuts on the gums and roof of the mouth. Furthermore, the inside of the mouth is naturally home to hundreds of kinds of bacteria and microbes -- some of which the body considers hostile. When those hostile microbes get into those tiny injuries, it causes a low-grade infection that can literally last for years if you keep re-scraping up the inside of your mouth.

That infection, in turn, leads to a constant low-grade inflammation. Inflamed cells don't respond as well to normal inter-cellular chemical signals, including the signal that tells the cell to die if it starts to act abnormally. If something unusual happens to a cell that causes it to act like a cancer cell, and then the normal self-protection message fails to kill the cell, it can become cancerous. Thus, oral bacteria act as an enabler of carcinogenesis.

The major flaw in this theory is that it doesn't explain why one of the inflamed cells may start to act like a cancer cell. It assumes that, essentially, cells in your body are constantly 'going rogue', starting to act like cancer cells, and then getting killed by your own body. Interestingly, this is another commonly-accepted theory about how cancer works, but when you build one theory on top of another unproven theory, you have to take the whole thing with several grains of salt.

That doesn't mean that there's a flaw in the math -- there's definitely a relationship between oral disease and cancer -- it just means we don't know exactly why.

Getting Into the Data: In Depth On Oral Bacteria and Cancer

Last week we put up several links to studies that show a pretty clear link between oral bacteria and cancer. We couldn't help but think that perhaps it would be helpful to some of you if we translated at least one of them from scientific jargon into layman's English. From The Journal of Oral Microbiology:

"Inflammation caused by infections may be the most important preventable cause of cancer in general. However, in the oral cavity the role of microbiota in carcinogenesis is not known. Microbial populations on mouth mucosa differ between healthy and malignant sites and certain oral bacterial species have been linked with malignancies but the evidence is still weak in this respect. Nevertheless, oral microorganisms inevitably up-regulate cytokines and other inflammatory mediators that affect the complex metabolic pathways and may thus be involved in carcinogenesis. Poor oral health associates statistically with prevalence of many types of cancer, such as pancreatic and gastrointestinal cancer."

What this says, in short, is that many cancers are indirectly caused by infections -- indirectly because it's not the infection itself that causes the cancer, but instead the inflammation caused when your body fights the infection. In addition, this is inflammation that certain bacteria in your mouth can make much, much worse. We haven't figured out exactly how these bacteria cause cancer, so we can't say for certain that they do -- but the statistical correlation between oral health and cancer risk is quite significant.

"Our unpublished results from a cohort study in Sweden with 16 years of follow-up showed that age, female gender, and periodontitis with loss of the first mandibular molars were the principal independent predictors of cancers in general, and breast cancer in particular, as registered in the Swedish Cancer Registry. From the same database, premature death of young individuals was observed to link statistically with periodontitis and missing molars whether the cause of death was because of cancer, cardiovascular, or gastrointestinal disease."

This is the quote we referred to in this months' newsletter. Translated, it says that there are three factors that are the most correlated with breast cancer. The first is the age of the person. The second is their gender. The third is whether or not they had periodontal disease when their first molars were removed.

Why is this considered just as relevant as age and gender? Because it's statistically correlated to an extraordinary degree; if you had periodontal disease when your first molars came out, you were much more likely to get breast cancer. It’s not quite the difference between getting breast cancer as a man and getting breast cancer as a woman, but close to the difference between getting it as a 25 year old and getting it as a 35 year old.

The Hard Science of Soft Sciences

Here at Drs. Eric Johnson and Tom Risbrudt's office, we spend a small but significant portion of our time keeping up on the latest in dental research, from the cutting-edge (no pun intended) pharyngeal surgeries out of Switzerland to the UC Berkeley medical students pumping out research papers about the effects of non-fluoride toothpaste. As mentioned last month, one of the things we see more and more is that there really isn't a distinction between oral health and general health. If your mouth is unhealthy, your body will be too, and vice versa.

But there's a kind of problem with biological sciences. They're referred to by some as 'soft' sciences, because there are just so many variables involved with any form of life that two seemingly identically sets of circumstances can come up with radically different results (ask the scientists studying which diets are best for fat loss!) So a single study that says 'oral bacteria are linked to increased pancreatic cancer risk' is interesting, but until four or five other groups have come up with studies saying the same thing, that's all it is -- interesting.

As it happens, however, the link between breast cancer and oral health isn't just a one-off event. It's been shown in several studies from all over the world:

• The Journal of Oral Microbiology
• Medical News Today
• The Journal of Translational Medicine
• Journal Portal of Shahid Beheshti Medical University

So we at Drs. Eric Johnson and Tom Risbrudt's office are very confident that, when we say that we're doing our part to help fight cancer, we mean it. Not only did our team support the Support G. Komen Walk for the Cure, we also participated in the event last month. We know that the work we do right here every day -- keeping people's mouths healthy -- helps reduce their risk of cancer as well.

 That feels pretty darn good.

Let's All Take PhysEd: The Power of Exercise on Oral Health

We've talked a lot in the past about the importance of nutrition on oral health, and just a couple of weeks ago, we mentioned that getting enough sleep has a profound effect on your body's ability to keep its mouth healthy. Today, we're breaking out the third leg of the 'tripod' of general health: exercise.

According to studies published in the American Journal of Clinical Nutrition and the Journal of Dentistry, exercise and dental health are closely linked. One study divided up people into three groups: inactive, partially active, and extremely active. They discovered that the partially active people had 33% less periodontal disease than the inactive group, and the extremely active group had 52% less than the inactive group.

Another study showed that vitamin D, which is most commonly obtained from exposure to sunlight (which means being outside, which generally means being active), also helps suppress gum disease -- people with the highest levels of vitamin D had 20% less than people with the lowest amounts.

The reasons why this might be are somewhat complex, but they're thought to relate to the body's ability to process blood sugar. Science has proven that gum disease and blood sugar are closely related in ways we haven't discovered -- people who get gum disease also suffer from reduced ability to process blood sugar and people who lose the ability to control their blood sugar (due to pre-diabetes, hormonal imbalance, or other issues) also become more prone to gum disease.

Because getting exercise and getting vitamin D both help the body control its own blood sugar levels, they seem to, through that same undiscovered mechanism, do an excellent job of helping your body fight off periodontal disease.

So in short, get your kids into P.E., after-school sports, or whatever it takes to keep them moving! Along with a good diet and plenty of rest, it's an essential part of keeping up their oral (and their general) health.

Roughhousing at School: What to Do about Injured Teeth

Depending on your child and your school, there may or may not be a bit of roughhousing that goes on during the day. While most such play, as long as it doesn't devolve into bullying, is looked upon as a normal part of growing up, it does carry with it the chance of injury. If something happens to your kids at school and one of their teeth is chipped, cracked, broken, or worst of all, comes out, you need to know what to do.

Let's go from worst to least:

Tooth Comes Out

If a kid's first tooth comes out, it's just a matter of waiting until the adult tooth comes in. If an adult tooth comes out of your kid's mouth, it's panic time. They've got less than an hour before the tooth and the socket die and the tooth cannot be reattached.

Here’s what to do:

• Put the tooth in a glass of milk, or, if milk isn't available, in a glass of salty water.
• Take the tooth and the child directly to a dentist who does surgery; preferably a reconstructive dentist.
• Have the tooth put back immediately.
• Expect the child to take the next day or two off of school while they recover -- oral surgery isn't easy.

Broken Tooth

If a tooth actually breaks off -- not just a chip, but a substantial break -- you need to hurry to the dentist. Depending on the break itself, it may be more effective for the dentist to glue the broken piece back on, or it may be better for him to make a porcelain cap to go over the butt of the tooth.

Cracked Tooth

When a tooth is cracked -- as in, the enamel has a visible, jagged opening in it -- it's still immediately dentist time. The child still shouldn't attempt to eat anything even if they feel OK. The dentist will almost certainly fill in the crack with some sort of enamel-like substance, and your kid should be ready for school the next day.

Chipped Tooth

It's not often that you can find the chip when a tooth gets chipped. If you can, you should head straight to the dentist to get it reattached. If you can't, you could way for a day or three, or not, it's up to you, because whether you do or not, the dentist is going to do the same thing -- fill in the chip with a tiny bit of porcelain and seal it in place.

Back to School Tips: Better Sleeping for Better Teeth -- And Grades

This one is for all the kids, but will help teenagers more than the rest. Did you know that according to one study, kids today get an hour less sleep, on average, than we did when we were young? It's not hard to see why -- it's perfectly normal for a kid these days to have school until 3pm, sports until 5, dinner, prime time TV (aka "family time") until 8 or 9, and then 3 hours of homework on top of that.

Add to that the fact that, around 14 or 15, a teen's internal clock changes to allow (and to a degree require) them to stay up later than they did before. But the times they are required to wake up in the morning don't budge -- and you can see the problem. If kids could sleep in an hour later in the morning, they'd be fine -- but they can't, and over the months and months of school, all those lost hours of sleep add up. So a good night's sleep is good for your kid's health.

So how can you help your child get to sleep a little earlier? Here are a few things you can do:

• Turn off all electronic screens at least an hour before bedtime. No TV, computer, iPod, tablet, smart phone -- nothing with an electronic screen.
• Have a story ready. It doesn't have to be in a book. A recording or someone to tell you a story will work, too, but having something for the brain to focus on that isn't the stress of the next day helps your brain relax and fall asleep.

Keep a regular schedule. Dinner at 6, shower at 9, in bed by 10, every night (assuming they have to be up at 6). Falling asleep should be as regular as waking up in the morning.

Naturally, you should schedule at least 8 hours for them to sleep each night.

Oral Hygiene at School: The Importance of Having Floss on You At All Times

There are some things that are just so useful that once you have them on you for a while, you start to wonder how you ever got by without them. Simple, waxed dental floss is one of those things. Just look at what you can do with dental floss:

• Tie up a shoe whose lace has broken.
• Create a makeshift tourniquet to get a cut finger to stop bleeding so much.
• Cut cheese, modeling clay, or other soft things.
• Put a tripwire up across a bathroom stall.
• Combine it with a paper clip and a pencil to create an in-class zipline.
• Use it to tie your hair back should your scrunchie stop scrunching.

Of course, you can -- and should -- also use it to floss your teeth. Why would you want to do something that lame in the middle of the school day?

There are a couple of good reasons:

Something Hurts

It's not all that often that we can identify exactly why something in our mouth hurts, but when it does, it's more often than not in a place that we can't quite get to. It's a bit vulgar to walk around school trying to get between your teeth with a fingernail -- but floss is completely socially acceptable.

Something is Stuck

Along those same lines, there's very little more distracting than having something annoying stuck between your teeth. Also, as it happens, those bits of food stuck between your teeth are quite bad for your oral hygiene -- each of those bits is a source of food for the bacteria that cause plaque, gingivitis, and other diseases of the teeth and gums. Flossing is the best way to get them out efficiently and without causing a fuss during the school day.