Two weeks ago the dental community was in an uproar. Morning news shows were making claims that “dental x-rays cause brain tumors” and “dental x-rays are linked to brain tumors.” What made dentists so mad? For one thing, dentists are an easy target. Many people have had bad experiences with dentists, many people are afraid of shots and a lot of folks associate toothaches with dentists. Dentists have baggage, and this news story didn’t help. So we’re kind of touchy.
There are a couple problems with the Yale research that these news stories were based on. First, the methods used in the study were questionable. But even if the results had been accurate, the news media took “x is related to y” to mean “x causes y.” This is a conclusion that the data do not support. There’s a lot more work that would need to be done before that conclusion would be fair. Just because red cars are twice as likely to be in accidents as blue cars, you cannot assume that the color of the car is what’s causing all the accidents!
Humans are kind of funny that way. Our brains love to “assign a cause.” We like to take two things that are proven to be related in some way and jump to a conclusion. Usually the conclusion we jump to is: “one thing is caused by another.” Dentists do it, too.
A recent statement from the American Heart Association has taken the dental world by storm over the last few days. Apparently the assumption that many dentists made about periodontal disease causing heart disease was firmly clarified by the AHA:
“The message sent out by some in health care professions that heart attack and stroke are directly linked to gum disease can distort the facts, alarm patients and perhaps shift the focus on prevention away from well-known risk factors for these diseases.”
Boom. That seems very clear to me. The statement continues:
“Although periodontal interventions result in a reduction in systemic inflammation and endothelial dysfunction in short-term studies, there is no evidence that they prevent ASVD ["atherosclerotic vascular disease" aka heart disease] or modify its outcomes.”
From what I can tell, the American Heart Association is saying “don’t use heart disease as a scare tactic about gum disease.” I think that’s fair. I’ve noticed for years that some dentists have played a little fast and loose with the relationship between gum disease and heart disease. The truth of the matter is that gum disease and heart disease share quite a few risk factors: smoking, age and diabetes to name a few. Gum disease is worth treating in its own right. Potential tooth loss, pain and bad breath are pretty compelling reasons to keep your gums healthy. It’s just that dentists were getting comfortable lumping potential systemic problems in with the other problems gum disease presents as a selling point to the treatment. This is intellectually lazy and we need to re-evaluate it.
Perfect
The moral of the story is this: “is linked to” does not mean “is caused by.” Even when your brain really wants to take that leap, you need to take a step back and really look at the relationship between whatever variables are connected.
Did you find this post interesting? Thought provoking? Tedious? I’d love to hear about it! You can share any Mead Family Dental post with a “Like” on Facebook, a “+1″ on Google+ or you can even “Tweet” it with Twitter! All you need to do is hover over the heart shaped button next to the title of the post. Or you can leave a comment by clicking on the balloon shaped icon next to the title.
If you’re looking for a dentist in Saginaw, we’re always happy to accept new patients! You can request an appointment online or call the office at (989) 799-9133. And, as always, you can email me at alan@meadfamilydental.com. I always answer my own emails!
I recently wrote about some new research that connected dental x-rays to a common brain tumor called a meningioma. Unfortunately, the news media took the “connection” from the research and made some pretty sensational claims. It made a lot of dentists pretty mad and it made a lot of patients pretty nervous.
Today I got a suggestion from a Facebook friend:
“Al, I’ve seen the phrase ‘levels of radiation that are so small as to be insignificant’ used a fair bit in the last few years. Particularly in relation to the Japanese disaster and the observation of levels of radiation around the world due to it…I think it would be instructive to have hard numbers to compare to background and other common sources that are considered safe.”
I agree. I’ve been explaining how safe x-rays are to patients for so long, I’ve kind of forgotten about the actual amounts of radiation that we expose them to. So let’s talk a little bit about radiation.
Electromagnetic radiation like visible light and x-rays travels in waves. And I have a cool graphic of it.
Electromagnetic radiation, or EMR, is any form of energy that travels in a wave. Visible light, radio waves, microwaves and x-rays are all forms of EMR that are common to us. The different types of EMR are characterized by their wavelength and frequency. Longer wavelength radiation like radio waves and have a lower frequency and are considered “low energy.” The shorter the wavelength the higher the frequency of the energy and generally these are “higher energy.” Very high energy like x-rays and gamma rays that can cause an electron to break away from an atom are considered ionizing radiation. These are the kinds of radiation that can cause health problems. Too much ionizing radiation can cause damage to the DNA in a person’s cells, which can lead to tumor formation and even cancer. The high energy state of x-rays is also what makes them so useful for seeing structures inside the body. Visible light is stopped by the skin and soft tissues around your bones and teeth, but x-rays can penetrate through them to show us things that we cannot see with visible light alone.
Harm from radiation sources is “dose dependent,” which means that more is worse. So in order to maintain safe levels of radiation in the dental office we need to know what kind of dose that we’re giving. The dose of radiation is measured in millirems or mrem. You can actually calculate common radiation doses using this chart from the American Nuclear Society.
So what is a “safe” level of radiation dosage? According to the American Nuclear Society the average level of radiation per person in the United States is 620 mrem/year. The safe allowable dose for people that are exposed to radiation in their work (nuclear plant workers, radiology technicians) is 5000 mrem/year.
Here are some examples of radiation dosages for different common exposures:
1 bitewing or PA dental x-ray: 0.5 mrem
2 hours in a jet plane: 1 mrem
1 panoramic dental x-ray: ~3 mrem
living in a stone, adobe or concrete house (instead of wood frame): 7 mrem/year
a full mouth set of dental x-rays: 9 mrem
chest x-ray: 10 mrem
1 pack of cigarettes each day: 36 mrem/year
chest CT scan: 700 mrem
whole body CT scan: 1000 mrem
These numbers reflect conventional film x-rays. Many dentists use digital x-ray technology which needs significantly less radiation to make x-ray images. In some cases the amount of radiation needed is 80% less than conventional film radiography, which would yield even lower radiation doses.
How much is too much?
Even though dental x-rays have an incredibly low dose of radiation, it makes sense to limit the amount of radiation as much as possible. Patients with a proven track record of low decay rate are an example of a type of patient that may not need diagnostic x-rays each year. Other diagnostic methods like high magnification with intense lighting, evaluating saliva flow and dietary evaluation can help determine a patient’s risk for new decay. For patients who have experienced cavities recently or new patients that don’t have a track record with their dentist, taking dental x-rays on a regular basis is necessary diagnostic tool.
So what’s a patient to do? How do you know if an x-ray is necessary? You need to ask your dentist. And if you don’t feel like your dentist is hearing you, perhaps you need to find another. Having a relationship with a dentist whose opinion you trust is a great way to know that you’ve found a good balance between too many x-rays and not enough information to prevent dental problems.
Did you find this post helpful? Zealous? Wonderful? I’d love to hear about it! You can share any Mead Family Dental post with a “Like” on Facebook, a “+1″ on Google+ or you can even “Tweet” it with Twitter! All you need to do is hover over the heart shaped button next to the title of the post. Or you can leave a comment by clicking on the balloon shaped icon next to the title.
If you’re looking for a dentist in Saginaw, we’re always happy to accept new patients! You can request an appointment online or call the office at (989) 799-9133. And, as always, you can email me at alan@meadfamilydental.com. I always answer my own emails!
A new study attempting to correlate dental x-rays in the past to an uncommon benign brain tumor was published today. And the headlines are scary! A cursory Google search of todays news yields these headlines:
“Are Dental X-rays Causing Brain Tumors?” (reported by KGO-AM)
“American Cancer Society study links dental x-rays to tumor” (reported by ABC Action News)
“Dental x-rays linked to common brain tumor” (reported by Reuters)
Early Dental X-rays Linked to Brain Tumors” (reported byABC News)
You get the picture. If you read the headlines and listen to the superficial news story you could walk away with the message that “dental x-rays cause cancer” or more likely “dental x-rays = bad” and “avoid dental x-rays.”
I am a dentist. I use digital x-rays to help me diagnose dental problems all day long. I really don’t want to think that all these x-rays I’ve taken over the years are causing horrible things to happen to my patients. I think it’s worth taking a good hard look at how the research was done and what it really says.
studying “past exposure”: The newly published study deals with past exposure of x-rays. Current standards for film x-rays use much less radiation than past standards. Digital x-rays use much, much less than current film x-rays. So any findings of this research only deals with your exposure in much earlier life. Technology has essentially solved the problem of higher exposure to dental x-rays already.
Do you remember?
using patient’s memories: The new study is a case control study. Case controls are useful, but are one of the weaker forms of medical evidence out there. The study compared two groups. One group was composed of patients who have already been diagnosed with a meningioma and the other group of patients did not have the condition*. The researchers asked the patients in the study to remember how often and what kind of dental x-rays they had in the past. So the data for the study was dependent on what the patients remembered. Can you tell me what kind of x-rays you had in 1995? Can you tell me whether a panoramic x-ray was taken instead of a full mouth set of x-rays? I’m not critical of the study being done nor of the researchers. That is how case control studies are done. I’m much more critical of how the media is portraying this evidence.
type of tumor: A meningioma is a “benign”/rarely cancerous tumor. It is the most common brain tumor. Meningiomas are tumors that occur in the membranes lining the brain and spinal cord. They can range in severity from occult (the patient didn’t know that they had the tumor) to life threatening. Common complications are seizures, localized neurological problems (muscle spasms) and they can cause increased intracranial pressure. Depending on their location they can “crowd out” vital structures of the head and neck. More severe meningiomas often require surgery, and sometimes radiation therapy. The cause of this type of tumor is not well understood, although there is evidence that genetics plays a part. The current study was done in an effort to understand potential causes. I don’t mean to downplay the seriousness of a meningioma. Since I originally wrote this blog post I have heard from many survivors of meningioma and they assured me that I definitely had downplayed their severity, and for that assumption, I apologize. The most severe type can be debilitating and even life threatening. Luckily, the majority are not this serious. The bottom line…dental x-rays don’t cause cancer, they don’t cause brain tumors and this research doesn’t claim that they do.
“is linked to”: The media loves to make the connection that “A is linked to B.” It makes great headlines. But it almost never means what the media portrays it to mean. “Is linked to” is not the same as “is caused by.” “Is linked to” or “is correlated with” only means that there is a relationship between the two factors. The new research shows that there is a relationship, but it’s not reasonable to assume that one causes the other, yet. More research will be done that may help us refine our understanding of these relationships, but until then…don’t assume!
So, should you have a talk with your dentist about x-rays? Absolutely! Should you avoid them at all costs? No. Not at all. The amount of radiation used with digital x-rays is so small as to be considered insignificant. The amount of radiation from dental x-rays is surprisingly low relative to some other common exposures…you might be surprised! Treatment or lack of treatment should be based on the amount of risk that the treatment can cause. A frank discussion with your dentist should help you understand that modern dental x-rays, particularly digital x-rays, are a very low risk diagnostic tool that offer great preventive benefit.
Did you find this post helpful? Silly? Scandalous? I’d love to hear about it! You can share any Mead Family Dental post with a “Like” on Facebook, a “+1″ on Google+ or you can even “Tweet” it with Twitter! All you need to do is hover over the heart shaped button next to the title of the post. Or you can leave a comment by clicking on the balloon shaped icon next to the title.
If you’re looking for a dentist in Saginaw, we’re always happy to accept new patients! You can request an appointment online or call the office at (989) 799-9133. And, as always, you can email me at alan@meadfamilydental.com. I always answer my own emails!
* Actually, the group was assumed to not have a meningioma…the researchers took the patient’s self reporting of no meningioma as the same as “no disease.” Since often the condition displays no symptoms, this isn’t a good way to choose a control group.
Here's how it's supposed to work. The patient comes in with a problem. The dentist (that's me) looks at the patient, evaluates the x-ray, examines the tooth or teeth in question and tells the patient in no uncertain terms "you need a filling," "you need a root canal," or "this tooth can't be saved." The doctor knows and tells the patient what they should do, right?
Here's the problem. Each of those treatment recommendations kind of jumps a step. I shouldn't recommend treatment without first explaining the diagnosis.
Merriam-Webster gives us a few different definitions for the term diagnosis. First is: "the art or act of identifying a disease from its signs and symptoms." This is probably the most typical way people think of diagnosis. This is how we can tell a cavity from gum disease. They present with different signs and symptoms. A sign is an objective measure of condition in the mouth. Examples of "signs" are periodontal (gum) measurements or x-rays. These are collected by the doctor in order to form a diagnosis. Symptoms are subjective experiences of the patient. Common symptoms of dental problems are pain, "discomfort" and pressure. They aren't measurable in the same way that signs are but that doesn't make them any less real. Symptoms are described by the patient and interpreted by the doctor in relation to the objective signs collected.
Another defintion of diagnosis is: "investigation or analysis of the cause or nature of a condition, situation, or problem." I prefer this definition because it describes an active search to get to the bottom of the problem presented.
Some dental diagnoses (plural of diagnosis) are very straightforward. A cavity found on the x-ray and verified with magnification and lighting and recorded with an intraoral photo is dentistry's version of the slam dunk. This is a very common finding and the likelyhood of a dentist getting it wrong is very low.
Other conditions require us to be a bit like a detective. Sometimes we find ourselves settling on a differential diagnosis. The differential diagnosis is a list of the most likely things that could be causing our problem. For instance, "the tooth needs a root canal" isn't a diagnosis. That's a recommended treatment. A differential diagnosis might be "the nerve of the tooth is inflamed from a deep cavity. It may be able to heal from this trauma (reversible pulpitis) or it might be on it's way to dying (irreversible pulpitis). There are some signs and symptoms that help us determine which way it's heading. And sometimes, we just don't know!
Next time you're visiting your dentist or your doctor, ask them to talk about the diagnosis. One thing I can promise, they'll be surpised that you asked. You'll be letting them know that you're an interested patient who wants to take an active part in their care. I promise that you won't regret asking!
Are you interested in working with a Saginaw dentist who explains the diagnosis? Then I'm interested in having you as my patient! Drop me an email at alan@meadfamilydental.com (I always answer my own email!) or call the office at (989) 799-9133. We'll get you in right away and you won't believe a dental office can treat you so well!
So I had a patient in the chair earlier today. I got a look at his teeth and said, “you have heartburn, don’t you? You suffer pain in your chest and throat after eating Italian food.”
He got this look on his face. It was kind of scared but also kind of amazed. It was as if Sylvia Browne had told him about a relative of his from beyond the grave!
The difference is, Sylvia Browne uses cheap parlor tricks and I’m for real!
What’s my secret? Was I born with this amazing power? Have I trained under experienced psychics?
Nope. I’ve just seen a ton of gastric reflux patients. They have telltale acid erosion spots. They show up most often on lower molars. Once you realize they aren’t necessarily from bruxism (a.k.a.”night time tooth grinding”) I see them a lot. The amazing thing is that 25% or more of patients with gastric reflux don’t have any symptoms! No heartburn, no itchy throat, no noticeable bad breath. On top of that…these erosion area on the teeth usually don’t hurt. They’re often only detectable by a dental exam. This is particularly scary because untreated gastric reflux is a leading cause of esophageal cancer, and esophageal cancer is particularly bad!
This Saginaw dentist is trying to impress you with his amazing powers. But have no fear…there’s nothing supernatural here!
Do you have questions about your teeth? Would you like more information about gastric reflux or other topics I’ve talked about? Feel free to email me at alan@meadfamilydental.com (I answer my own email) or call the office at (989) 799-9133. I’d like to be your Saginaw dentist!
I recently bought a bottle of water at Walgreen. The brand was “Iceland Pure Spring Water” and it featured “pH 8.88″ prominently on the label. I read a little further to find:
“…it has one of the naturally lowest mineral contents of any water and a high pH of 8.88. Icelanders live longer than any other nationality; we believe their secret to long life is their water.”
This is an interesting claim. My research (if you want to call finding a cool chart Wikipedia chart research) shows Iceland coming in 3rd to Japan and Hong Kong. FYI…the U.S. comes in tied for 36th place with Cuba and Denmark. So the claim that Icelanders live the longest is in dispute, but what about the pH of their amazing spring water? Could it account for longevity? Should I be worried about my pH?
pH is a measurement of acidiy or alkalinity in an aqueous (water based) solution. A solution that is high in acidity has a low pH and a solution that is more alkaline has a higher pH. pH is measured on a 14 point scale with 0 being the lowest pH (most acidic) and 14 being the highest pH (most basic or alkaline). A pH of 7 is considered neutral, neither majority acid or alkaline. This 14 point scale is logarithmic, which means that each number on the scale is 10 times higher or lower than number above it or below it. For instance, a substance with a pH of 3 is 10 times more acidic than a substance with a pH of 4 and 100 times more acidic than something with a pH of 5.
The pH of the human body is variable depending on the part of the body you’re talking about. The stomach has a pH of about 1…very acidic. This is useful in breaking down the food into smaller, more digestible pieces. Lysosomes, the small bags of chemicals found inside cells are used to break down damaged cell parts. They can have a pH of 4-4.5. Our blood is at a relatively steady pH of 7.34-7.45. The body keeps the pH of our tissues relatively constant completely separate from our diet.
Our mouths are a bit of an exception. The pH can range quite significantly in our mouths due to the presence of acid producing bacteria. Some of the bacteria in our mouths can turn the carbohydrates that we eat into acid. I’ve talked quite a bit about this inpreviousposts. This acid can dissolve the surface of the tooth if it reaches a critical pH. The critical pH, or the pH at which tooth structure begins to dissolve is 6.7 on the root surface of the tooth and 5.2 on the enamel. Diet, habits and saliva flow have a lot to do with how well an individual defends against pH drops in the mouth. But these localized oral pH fluctuations are not the same as pH change of the body.
You often hear claims that the pH of your body being off or unbalanced are the cause of disease. Whether these claims are indirect like my water bottle or more direct as in some blogs or books, they need to be looked at critically. Most of these claims have no basis in science or actual physiology. Beware of diets or claims that talk about “changing your body pH.” Often they direct you to test your saliva to evaluate your body’s pH. That would be akin to checking the inside of your furnace to evaluate what the temperature of your house is! Your body has very specific control mechanisms for regulating your pH through the lungs and kidneys. Your diet makes no difference with regard to your body’s pH, except in your mouth!
Some disease states can result in pH changes. Diabetics can experience diabetic ketoacidosis, which can lower the pH of the blood. This is a consequence of their inability to use sugar in their bodies. However, in healthy individuals this is not a concern.
So, do I think my Iceland Pure Spring Water at a pH of 8.88 will prolong my life? Not really. However, it was cold and delicious and made it so I wasn’t so thirsty. So it did what I was hoping it would!
Do you have comments or questions about this or any of my other posts? Do you like what you see on my blog? Leave a comment here on the blog or feel free to email me at alan@meadfamilydental.com. This Saginaw dentist writes all the posts and answers his own email. Thanks for taking the time to read!
Recent headlines suggest that those who drink diet soda are more likely to have cardiovascular problems, specifically stroke. Let's review some of the headlines:
If you don't look any harder you could walk away with the idea that drinking diet soda will lead to strokes. And if you're anything like me, this will lodge in your mind until the next sensational headline tells you something else that many people do on a regular basis is unhealthy and damaging.
Does drinking diet soda really make you more likely to have a stroke? A stroke is damage to the brain due to a temporary interruption of the blood supply. It's very similar to the damage to the heart during a heart attack. What exactly is it in diet soda that makes it more likely for a stroke to happen? According to the articles this same risk isn't found in people who drink regular soda. So are we to assume that it's the artificial sweeteners?
This is a perfect example of preliminary "science" prevented as fact used as a scare tactic. Many news sources have gotten honest about the source of this information, but many others have not. Retractions or good explanations of the methods don't make headlines, but scare tactics do.
The correlation between diet soda and stroke was made in a poster presentation at the "International Stroke Conference." Poster presentations are not the same as peer reviewed medical journals and definitely do not carry the weight of medical consensus. This misinterpretation is not the fault of the scientists presenting the poster so much as the media drawing unsupported conclusions. Simply stated, the connection presented has not been studied enough to make the statements that a lot of news sources are making.
Most news stories do not bother to mention that correlation isn't the same thing as causation. There very well could be a correlation between intake of diet soda and stroke, but by no means does that mean drinking diet soda causes strokes. It's that the individual data points of stroke risk and diet soda intake are often found together. Perhaps overweight and obese people, who are clearly more likely to have strokes and heart attacks, are more likely to report drinking diet soda because they are attempting to lose weight. Perhaps there really is some stroke inducing ingredient in diet soda. The study that is referred to really doesn't make that evident. There needs to be a lot of research and verification to reach a point where causation of disease can be determined.
The news media and others reporting the "drinking diet soda = greater stroke risk" are jumping the gun. They're not interested in reality as much as a good story. A story that might frighten you, but will hopefully be forgotten until the next scary headline.
Is this ever done in dentistry? I think it is. I'll discuss that in another blog soon!
