Dental Ass't: Cavities by Bacteria? Heart Plaque = Teeth Plaque? Etc.
February 1, 2005 11:27 AM   Subscribe

My dental assistant has made a lot of interesting, maybe controversial claims. I'd like to know how common these ideas are, and how well supported. [+]

I've been going to the same dentist/assistant for many years now. She always says a few things that startle and
surprise me, and when I bring them up with other people, they're skeptical. I am too, a bit, although I generally defer
to professionals. Anyway, wanted to run these by and see if anyone else was familiar with these concepts.

* This one seems the least controversial, and some parts of it I know to be true: cavities, peridontal disease, etc, are
caused by bacteria. Her claim though is that you could be born without it, and thus never get any cavities or gum
disease, etc. You can catch it (generally by mouth) from another carrier though, and it's impossible to eradicate. She
didn't know what percentage of people carried it but thought that it might be the majority. This actually came up
because my spouse and her family have an extremely low incidence of cavities, etc, and I wondered aloud whether this was
due to resistant teeth or what.

* She said that the plaque on your teeth is the same as the plaque around your heart and kidneys (um, might have been
gall bladder or something and not kidneys, sorry, I spaced a little)

* As an addendum she said that you can guage the health of a person in a large part by examining their mouth

* She claimed that your body gives priority to the mouth when fighting infections, with the exception of the heart and
the brain. That is, if you have a low-grade infection in your mouth, your body will fight that before fighting other
diseases, with the exception that the mouth comes third after the heart and brain. The idea she was trying to get
across was that if your mouth was healthier you would have more resistance to other diseases because you wouldn't be
fighting the infection in your mouth.
posted by RustyBrooks to Health & Fitness (20 answers total)
The first one is true. The second is false.

Dunno about the third and fourth, other than to note that the third seems susspicuously self-serving, and that your last statement in the fourth is fairly tautological: the less your immune system has to do, the less your immune system has to do. I've never heard about the body favoring the mouth, though.
posted by Zed_Lopez at 11:50 AM on February 1, 2005

* Her claim though is that you could be born without it,
Yes, I've heard this as well from Dentists, when asking how I've avoided many cavities.

*plaque on your teeth
I think this is also true, plaque is a generic term for a build up of 'biostuff' but it need not all be the same stuff

* guage the health of a person
This one sounds like a stretch of the "don't look a gift horse in the mouth bit", that said many ailments can be guaged from the mouth, in a routine examination Doctors pull out the flashlight and tongue

* priority to the mouth
No, clue.
posted by dirtylittlemonkey at 11:51 AM on February 1, 2005

My dentist was always amazed at how resistent my teeth were to cavities, even going to far as to suggest that X-rays make it look as if my teeth have healing powers. Perhaps he was just being convivial, but it supports the idea that certain people's teeth are remarkably resistent to bacteria.

However, I tend to think that it has something to do with one's saliva. Perhaps my saliva has a higher amount of bacteriocidal enzymes, or builds enamel better than others.

Plaque is plaque is plaque? Eh, probably not.

I believe that you can probably tell the health of a person by the health of their mouth. From halitosis giving you ideas about their digestive system to bone density giving you an idea about their nutrition.

I have no idea about her last claim. Interesting hygenist.
posted by taumeson at 11:52 AM on February 1, 2005

The first two are correct, and the second two, although more subjective, are probably true as well. The finding that the plaque on your teeth is the same as the plaque around your heart and kidneys may be very new, because I caught wind of it from a professor who read an article on it a few months ago, in which case... she's on top of things!
posted by banished at 11:55 AM on February 1, 2005

* She claimed that your body gives priority to the mouth when fighting infections, with the exception of the heart and
the brain.

I've heard something similar: That wounds in the mouth heal fastest of all. Makes perfect sense to me, b/c it would allow the body to continue taking in nourishment.
posted by scratch at 12:00 PM on February 1, 2005

The last time I went to the dentist he talked about how enamel can regenerate. Has anyone else heard about this?
posted by bshort at 12:07 PM on February 1, 2005

Dental plaque and arterial plaque are not the same. Other have posted links that explain the difference.

The confusion may come from studies that suggest there may be a link between gum disease and heart disease. But all references to this idea I can find online refer back to studies in 1997 and 1998 that both said further research was needed and I haven't found any of that further research.

The American Acadamy of Periodontolgy site (in my first link) also has statements saying that oral health may be an indicator towards overall health, because a dentist can see signs of diseases such as diabetes or oseteoporosis, and refer their patients to a doctor. There is definately some truth to this claim, but they use this to promote people seeing their dentist so it seems a little self serving.
posted by raedyn at 12:13 PM on February 1, 2005

She said that the plaque on your teeth is the same as the plaque around your heart...

This isn't exactly true: the plaque in your mouth is significantly more calcified while arterial plaque has more fatty components, and the two types of plaque contain a different selection of flora. However, there are important connections between dental infections and risks for heart disease. Most directly, infections in the mouth can spread to the heart valves (bacterial endocarditis), leading (in the absence of medical intervention) to valve failure and death. This is especially a risk for people with artificial heart valves or valve defects; these people need to take special precautions (e.g. a course of antibiotics) prior to any dental care.

More generally, studies have strongly suggested that there is a connection between oral health and heart disease: poor oral health is a risk factor for coronary artery disease. I'm not sure if the mechanism of this connection is well understood.
posted by mr_roboto at 12:16 PM on February 1, 2005

It occurs to me that If the fourth is true, the third pretty much follows from it: if your immune system is so far behind the curve that it can't even keep your mouth healthy, then that doesn't bode well for the rest of your body. (Again, if the fourth is true.)
posted by Zed_Lopez at 1:16 PM on February 1, 2005

She is quite an interesting character. I have, ahem, learned not to engage her in conversation *too* much as she'll stand there and chat and I generally want to get it over with. I'm a hobby woodworking and home improver and let's say our tastes in that arena diverge too wildly to have conversations about it, but she always wants to. For example: she wanted wood floors in her kitchen but was afraid they'd get messed up so she put in ceramic tile that "looks like" wood. She has every appliance in her kitchen on wheels, including the refridgerator, stove and *cabinets*.
posted by RustyBrooks at 1:57 PM on February 1, 2005

mr_roboto: here's my two cents. There's a huge confound in that correlation.

People with poor oral health are often of low socio-economic status. People in America with low socio-economic status eat fatty gross foods more often than wealthier people. Ergo, more heart disease.

Yay confounds!
posted by u.n. owen at 1:58 PM on February 1, 2005

Claim, the third

completely-anecdotal-evidence-filter: during a check-up, a friend of mine was told by her dentist to immediately see her doctor based on the amount of plaque and condition of her gingiva. She consulted her primary care physician who recommended the mammogram that detected her breast cancer.

My friend suspects (though has not asked) that oral health wasn't necessarily an indicator of breast cancer specifically, but of her general condition (dire). She credits her dentist with saving her life. Your mileage may vary.
posted by Verdant at 2:15 PM on February 1, 2005

Funny that it's possible to damn your kid to a life of cavities vs. practically none by making frequent dentist's visits and avoiding sharing utensils etc. until they grow older that it's not well known.
posted by abcde at 2:34 PM on February 1, 2005

That reminds me of a totally unrelated story my eye doctor told of how he saw a brain tumor behind the eye of one of his patients, a child. It's a scary reminder to get all your check-ups, as one doctor might find something that they're not looking for!
posted by agregoli at 2:39 PM on February 1, 2005

The one about looking at the mouth and the heart--it might be this is what she is referring to. Infection of the gums (poor oral hygiene) can infect the heart. There have been studies to support this. I met a guy that had gingivitis and I knew from conversation he had recently had a heart valve replaced. I gently urged him to see a dentist. His dentist told him to thank his friend, because his gum infection could have an effect on his heart valve. Dentists also pre-treat patients with mitral valve prolapse with antibiotics prior to getting their teeth cleaned.
posted by 6:1 at 3:55 PM on February 1, 2005

And don't forget that those same people don't usually have much in the way of dental insurance, U. N. Owen. I'd go so far as to say a horrible diet is of next to no consequence, in terms of oral health, as long as one has adequate access to regular dental checkups and cleanings.
posted by luriete at 4:16 PM on February 1, 2005

re the fourth claim:
My eye doctor told me that the eye heals the fastest of any part of the body, often in a manner of hours if it is wounded. I don't know about infections, though.
posted by mai at 4:16 PM on February 1, 2005

Whoof. Not good.

Let's take a shot at it:

1. It makes some sense from a theory-of-bacteria perspective, but in practice it's impossible. Everyone's mouth is full of nasty bacteria all the time. I think even if you were lifted out of the womb directly into a bubble and fed sterilized food, you'd still eventually get colonized by bacteria. If you didn't, you'd certainly die - some of these are symbionts; they're not all pathogens.

The reason everyone's mouth doesn't decay into a rotting pile of pus is a) oral hygiene measures and b) the fact that your saliva is full of anti-bacterial antibodies.

2. Wrong, but not wrong-headed. Dental plaque is a thin, gel-like film of bacteria and their proteinaceous and acidic secretions. The calcification they leave behind is not plaque; it is called calculus.

Arterial plaque forms when cholesterol builds up under the inner layer of the arterial wall. This 'fatty streak' produces an inflammatory reaction, leading to infiltration of white blood cells; swelling; and hemorrage. The inflamed area eventually calcifies and this can break off, in whole or in part, so that you can have a big frondlike mass of calcium, arterial-lining cells, white blood cells, and old clot floating around in the stream of blood. That thing is called a 'plaque'. It is sometimes, not always colonized by bacteria, especially Chlamydia species, although there's some controversy about the exact role of the bacteria in plaque formation. Some scientists think that the plaque bacteria are important in intensifying the inflammatory reaction, and we know that anti-Chlamydia antibodies in your bloodstream, indicating exposure, put you at higher risk for heart attack. Chlamydia are not usually found in the mouth, incidentally.

So you can see that dental plaque and arterial plaque have basically nothing to do with each other, and the idea that arterial plaque has anything to do with bacteria is extremely recent.

3. A very good clinical physician said something similar to me once: "You can tell what kind of care someone takes of herself by looking into her mouth." It's not the same as what your hygienist said, but I think it's pretty close. Both statements are to some degree true and correlated, in my experience.

4. This is a hodgepodge of several different things which are somewhat true. Your body expends scant resources fighting brain infections, actually; it counts on the blood-brain barrier and other anatomical barriers to keep bugs out. Once you get a good infection like a brain abscess going, it's damn hard to get rid of it.

The mouth heals very quickly and is highly vascular; to say that it is more resistant to infection is correct as far as it goes. But to say the mouth is more resistant to infection than the liver, for example, is a bit silly - when was the last time you accidentally took a swig of spoiled milk WITH YOUR LIVER? That's usually done with your mouth, and your mouth is designed to be able to withstand such a thing.
posted by ikkyu2 at 9:05 PM on February 1, 2005

As others have confirmed, the first is true. The bacterium primarily responsible for cavities is Streptococcus mutans. I quote: "There is considerable evidence from animal and human studies showing that caries results from the transmission of Streptococcus mutans so, on balance, it is reasonable to refer to caries as an infectious disease.

Interestingly, this company believes it can prevent cavities by replacing the natural S. mutans with a genetically-modified version that doesn't produce acid (which is the proximate cause of cavities).

I'm pretty sure there's a genetic component to the susceptibility to cavities, not sure if it's known exactly how that works.
posted by greatgefilte at 6:50 AM on February 2, 2005

This might be relevant to the second point.
posted by Mark Doner at 9:37 AM on February 9, 2005

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