I agree that the interval period of dental radiographs should be based both on clinical findings and both caries and periodontal risk assessments neither of which are done in most dental practices. That being said, radiographic consultation is part of the clinical exam in dentistry because we cannot visualize many various lesions or bone health without them. I have found caries, cervical root resorption, abscesses, root fractures, cysts, and cancer on radiographs that were not evident via symptoms or clinical exam.
In regards to caries risk assessment, I use clinical findings of visible cavitations or demineralization, evaluation of the saliva, testing the biofilm, and questions about diet, breathing, sleeping, and medications.
I see mostly retired age patients who can have stable oral health until they don’t and it suddenly changes in the period of a few months. Usually this is due to them experiencing an extreme dry mouth from a new medication which they then palliative treat with either cough drops, candy, or constant sipping on some sort of acidic beverage. And the cavities just explode. Radiographs one year look great, and the next year I have to share devastating news. (BTW…Physicians almost never warn their patients about the misery and oral health risks of xerostomia from medications.)
My own father who was a dentist and meticulous with his oral hygiene and diet didn’t have radiographs for several years and when he did we found many large various lesions, one of which resulted in a root canal treatment. He had a shift in his saliva decreasing the buffering capacity which combined with his more acidic diet then shifted the biofilm despite his excellent daily plaque removal. By adding buffering (high pH) and remineralizing agents to his daily routine and tweaking his dietary timing, we stabilized his risk. We still, however, perform visual and radiographic exams on a more frequent basis now.
Is there money element here? Yes. Insurance pays for radiographs yearly and I can screen for changes. If I got paid for the time it takes to do thorough health histories and risk assessments, my business model would be easier to maintain.
I am a huge advocate of risk assessments and individualized care, but the liability, expectations, and reimbursement works against this. We need more of these open and multi-disciplinary conversations as well as good studies to support our decisions and practices.
Great read. VKP MD teased that he would take on the subject. Now that he’s moved up, I am glad to have this article. Maybe next one could be about dentists and bisphosphonates . Thank you so much.
Important to note the risks of radiation exposure are much lower with increasing age (and higher for young people). Ironic that more dental X-rays seem to be done in children.
A dentist relative who read this informs me of a few interesting points:
1. MANY caries are discovered radiographically. Caries are often not evident on clinical exam even amongst diligent dentists. Its apparently quite common that large caries are diagnosed via X ray when they are not apparent on exam and are also asymptomatic. We might be inclined to say "let's study early carry intervention vs watch and wait (however this would be nearly impossible to control for variables given how different peoples teeth/bite are, how different lesions are, the environment of people's mouths, habits, the skill of the dentist, materials used, and the inadequacy of XR to characterize lesions. I was told recently that a "small irregularity on XR turned out to be a large pile of mush cavity under the surface." It seems that many cavities are an N of 1. Also, someone who defers XRs might be labeled low risk, even though they have caries under the surface, but would be offered less frequent X rays thus delaying diagnosis.
2. Risk status assignment for caries seems a bit unscientific - for example, the dietary ADA factor that place someone at high risk according to their site is "Sugary Foods or Drinks: Bottle or sippy cup with anything other than water at bedtime (ages 0 to 6 years) or frequent or prolonged between meal exposures/day (ages >6 years)". However, I'm told by dentists that foods often not considered "sugary" are some of the largest risk foods (eg goldfish crackers, protein/granola bars, or similar starchy snacks that get stuck in teeth, 'electrolyte' drinks containing glucose, etc.. The standard American life is cariogenic, and I have been told that even the nuttiest of health nuts who come to see the dentist are often shocked to learn of their dental decay.
3. I think this post increases skepticism of dentists and screening X rays without properly acknowledging their value from the dentist's perspective.
I shudder to think all of the radiation my head has been exposed to over my 57 years. I had more than my share of dental work until I gave up sugar and most carbs about 10 years ago and have had much better dental health. Reading this Substack has only strengthened my skepticism about many routine medical practices and now, also Dental. I am so thankful for the excellent teaching I received so many years ago about evidence based medicine and the ways journal articles magnify benefits and hide harms. I appreciate finding my tribe here with Sensible Medicine.
Interesting timing. I saw my dentist yesterday - he's a wonderful dentist. He was very open to the conversation- I asked him can we forego rads if clinically my mouth looks good and if you find it's necessary based on my exam I will accept your expertise. He agreed- all looked good and he sent me on my merry way:)
I feel that we've lost looking a the patient and have come to rely on diagnostics - because we believe it's faster and easier and we're all under pressure from those overseeing to get in and out quickly wirh the bill!
Perhaps a look at the evidence behind dental cleanings should be next!
I like the European guidelines... they seem more reasonable even if there isn't much evidence to support any X-rays in asymptomatic people (which could be how risk is determined rather than "high risk of caries") if there isn't a high probability of finding something positive, then best not to do the diagnostic test.
Good discussion and I am sure that dental x-rays are overdone. I never gave it much thought as my dental contacts were usually about 10-15 years apart. Having spent many hours in the cath lab using fluoroscopy, I looked on the degree of exposure from dental x-rays as rather insignificant. My dental visits are a little more frequent as I have gotten older but I accept the occasional x-rays---go along to get along. The technology seems to have changed in the last few years. Can someone educate me on the current levels of radiation exposure compared to those in the past?
This discussion reminds me of the disconnect between population level/epidemiological evidence and recommending what I think is best to the patient sitting in front of me. As a practicing general dentist of 52 years and a volunteer faculty at my dental school teaching clinical practice, I do my best to apply accepted standard of care. A part of that SOC, which we teach our students, is the principle of "ALARA", as low as reasonably achievable. You and other commenters are correct that in many dental practices, these principles are overlooked in favor of doing whatever third parties pay for. Just like in medicine, unless you are in an off-the-grid concierge practice. The fact is that there are chronic conditions, especially dental caries and periodontal bone loss, which can be present without definitive clinical evidence. In those cases, dental radiographs are crucial in deterring the presence and severity. With the patient in front of me, I don't want to have to answer the question, "Why didn't you take care of this before I needed this root canal and crown or had to have this tooth extracted?" The key for me, just as it is for all of you, including my cardiologist , risk assessment and developing an appropriate plan for monitoring the patient. BTW, the dentist that didn't have you sign the consent to X-rays is in violation of standard of care and likely many state dental practice acts.
Very interesting post. And this fits nicely with the Sensible Med theme of questioning the yield of screening procedures in asymptomatic people. And also of how reimbursement drives procedures.
My dentist seems to offer/require films every 2 years. And as noted here, it’s always BEFORE the actual exam.
Dentists in my region (California) will not clean your teeth unless you agree to their x-ray schedule. For kids, dentists generally want to start x-rays at age 3. By age 7, most orthodontists insist on panoramic x-rays (and sometimes cephalometrics) just to monitor incoming dentition. Thank you for this important post -
Perhaps a sensible medicine post on the evidence behind dental cleanings is warranted. My last look found no evidence to justify these cleanings but it's been a while since I looked.
This says nothing about dental cleanings... only about "dental checks"... There are dental practices in the US who won't see you unless you're getting biannual "cleanings". Cleanings that make your teeth feel super smooth for two days and then it's back to the same teeth you had before the cleaning.
and here's an excerpt from a periodontist's response to my post
Valid point. Many dental practices treat by insurance benefits, since this requires so little cognitive effort by dentists or patients. If it’s cheap or free, why not? Imagine choosing your cancer therapy or whether to stent an MI based on insurance coverage. And yet, since dentists got in bed with insurers decades ago, this has become SOP. If you want a good dentist, choose one who is NOT contracted with your insurer. Then ask them to make the case for their recommendation based on health or your goals, not insurance benefits.
“More and more, I have become concerned about the radiation from medical radiologic procedures.”
You should. But do your homework and look up radiation doses from single intraoral images (periapical or bitewing). Most are in the 1 uSv range. Less than one day of background radiation from living your life. IMO this is a nothingburger.
Haha. Here's an excerpt from my post on skeptical thoughts from the dentist's chair
"The hygienist introduced herself (we’ll call her Donna), put away her crossword puzzle book, guided me back to the exam room and told me that she was going to do an X-ray. I wasn’t asked if I wanted an X-ray or explained the purpose of it, but dental radiography now seems to be the norm. Perhaps I am given one every time I visit a dentist because I go infrequently, much less than annually, and dental insurance tends to pay for an annual X-ray. The dental offices probably assume if it is free, no sane patient will reject it.
More and more, I have become concerned about the radiation from medical radiologic procedures (see my discussion on the radiation from coronary calcium CT scans here).
The hygienists are always careful to put a lead apron over my groin and around my neck, which makes me feel a little better, but I can’t help but wonder…what is the yield of the x-ray in a patient with no symptoms, what is the risk of developing oral cancer from the procedure if performed every year? And what is the probability that something will be identified that is not really a problem, which may lead to more testing or procedures?"
I empathize with Adam’s internal discussion at every dental appointment about how firmly to refuse X-rays, because I have the same recurrent argument.
I am grateful for this careful essay, but I have a number of questions about the state of knowledge about dental X-rays that weren’t addressed.
What are the criteria determining low risk status for caries in adulthood - age? Number of previous restorations? Age of existing restorations?
What is the positive predictive value of an X-ray shadow in a tooth suggesting early caries?
What is the value of surveillance of such a tooth (perhaps with more X-rays?)
I’d also like to know the ratio of the number of dental X-rays obtained in asymptomatic patients to the number of procedures performed based on those x-rays.
In regards to caries risk, number of existing restorations is considered a risk factor. I like to consider 3 primary factors in my risk assessment: saliva, diet, biofilm which are all inter-related.
Most prescription drugs cause a significant decrease in quantity and quality of saliva as does mouth breathing and sleep apnea. Without the buffering and hydration of saliva, caries risk goes up. If diet is sugary and acidic in high frequency such as sipping and snacking, risk goes way up. Both of these lead towards a highly metabolic cariogenic biofilm which can take a while to correct even when diet is improved.
Thank you for your comments. The American Dental Association provides information about caries risk assessment and management, including their own risk assessment forms for ages 0-6 years and >6 years:
Thank you for taking the time to send me to the ADA for more Information. Unfortunately, the ADA documents don’t answer my specific question. These answers are what would enable me to determine the usefulness of dental X-rays in common clinical situations. There is likely primary literature studying these issues.
I agree that the interval period of dental radiographs should be based both on clinical findings and both caries and periodontal risk assessments neither of which are done in most dental practices. That being said, radiographic consultation is part of the clinical exam in dentistry because we cannot visualize many various lesions or bone health without them. I have found caries, cervical root resorption, abscesses, root fractures, cysts, and cancer on radiographs that were not evident via symptoms or clinical exam.
In regards to caries risk assessment, I use clinical findings of visible cavitations or demineralization, evaluation of the saliva, testing the biofilm, and questions about diet, breathing, sleeping, and medications.
I see mostly retired age patients who can have stable oral health until they don’t and it suddenly changes in the period of a few months. Usually this is due to them experiencing an extreme dry mouth from a new medication which they then palliative treat with either cough drops, candy, or constant sipping on some sort of acidic beverage. And the cavities just explode. Radiographs one year look great, and the next year I have to share devastating news. (BTW…Physicians almost never warn their patients about the misery and oral health risks of xerostomia from medications.)
My own father who was a dentist and meticulous with his oral hygiene and diet didn’t have radiographs for several years and when he did we found many large various lesions, one of which resulted in a root canal treatment. He had a shift in his saliva decreasing the buffering capacity which combined with his more acidic diet then shifted the biofilm despite his excellent daily plaque removal. By adding buffering (high pH) and remineralizing agents to his daily routine and tweaking his dietary timing, we stabilized his risk. We still, however, perform visual and radiographic exams on a more frequent basis now.
Is there money element here? Yes. Insurance pays for radiographs yearly and I can screen for changes. If I got paid for the time it takes to do thorough health histories and risk assessments, my business model would be easier to maintain.
I am a huge advocate of risk assessments and individualized care, but the liability, expectations, and reimbursement works against this. We need more of these open and multi-disciplinary conversations as well as good studies to support our decisions and practices.
Financial incentives are not simply applicable, they are the explanation.
What I look for in a dentist is the same quality that I look for in a medical doctor:
1. They make recommendations and are completely fine with my decision even if it goes against their recommendations.
Great read. VKP MD teased that he would take on the subject. Now that he’s moved up, I am glad to have this article. Maybe next one could be about dentists and bisphosphonates . Thank you so much.
Important to note the risks of radiation exposure are much lower with increasing age (and higher for young people). Ironic that more dental X-rays seem to be done in children.
A dentist relative who read this informs me of a few interesting points:
1. MANY caries are discovered radiographically. Caries are often not evident on clinical exam even amongst diligent dentists. Its apparently quite common that large caries are diagnosed via X ray when they are not apparent on exam and are also asymptomatic. We might be inclined to say "let's study early carry intervention vs watch and wait (however this would be nearly impossible to control for variables given how different peoples teeth/bite are, how different lesions are, the environment of people's mouths, habits, the skill of the dentist, materials used, and the inadequacy of XR to characterize lesions. I was told recently that a "small irregularity on XR turned out to be a large pile of mush cavity under the surface." It seems that many cavities are an N of 1. Also, someone who defers XRs might be labeled low risk, even though they have caries under the surface, but would be offered less frequent X rays thus delaying diagnosis.
2. Risk status assignment for caries seems a bit unscientific - for example, the dietary ADA factor that place someone at high risk according to their site is "Sugary Foods or Drinks: Bottle or sippy cup with anything other than water at bedtime (ages 0 to 6 years) or frequent or prolonged between meal exposures/day (ages >6 years)". However, I'm told by dentists that foods often not considered "sugary" are some of the largest risk foods (eg goldfish crackers, protein/granola bars, or similar starchy snacks that get stuck in teeth, 'electrolyte' drinks containing glucose, etc.. The standard American life is cariogenic, and I have been told that even the nuttiest of health nuts who come to see the dentist are often shocked to learn of their dental decay.
3. I think this post increases skepticism of dentists and screening X rays without properly acknowledging their value from the dentist's perspective.
I shudder to think all of the radiation my head has been exposed to over my 57 years. I had more than my share of dental work until I gave up sugar and most carbs about 10 years ago and have had much better dental health. Reading this Substack has only strengthened my skepticism about many routine medical practices and now, also Dental. I am so thankful for the excellent teaching I received so many years ago about evidence based medicine and the ways journal articles magnify benefits and hide harms. I appreciate finding my tribe here with Sensible Medicine.
Interesting timing. I saw my dentist yesterday - he's a wonderful dentist. He was very open to the conversation- I asked him can we forego rads if clinically my mouth looks good and if you find it's necessary based on my exam I will accept your expertise. He agreed- all looked good and he sent me on my merry way:)
I feel that we've lost looking a the patient and have come to rely on diagnostics - because we believe it's faster and easier and we're all under pressure from those overseeing to get in and out quickly wirh the bill!
Perhaps a look at the evidence behind dental cleanings should be next!
I like the European guidelines... they seem more reasonable even if there isn't much evidence to support any X-rays in asymptomatic people (which could be how risk is determined rather than "high risk of caries") if there isn't a high probability of finding something positive, then best not to do the diagnostic test.
Good discussion and I am sure that dental x-rays are overdone. I never gave it much thought as my dental contacts were usually about 10-15 years apart. Having spent many hours in the cath lab using fluoroscopy, I looked on the degree of exposure from dental x-rays as rather insignificant. My dental visits are a little more frequent as I have gotten older but I accept the occasional x-rays---go along to get along. The technology seems to have changed in the last few years. Can someone educate me on the current levels of radiation exposure compared to those in the past?
This discussion reminds me of the disconnect between population level/epidemiological evidence and recommending what I think is best to the patient sitting in front of me. As a practicing general dentist of 52 years and a volunteer faculty at my dental school teaching clinical practice, I do my best to apply accepted standard of care. A part of that SOC, which we teach our students, is the principle of "ALARA", as low as reasonably achievable. You and other commenters are correct that in many dental practices, these principles are overlooked in favor of doing whatever third parties pay for. Just like in medicine, unless you are in an off-the-grid concierge practice. The fact is that there are chronic conditions, especially dental caries and periodontal bone loss, which can be present without definitive clinical evidence. In those cases, dental radiographs are crucial in deterring the presence and severity. With the patient in front of me, I don't want to have to answer the question, "Why didn't you take care of this before I needed this root canal and crown or had to have this tooth extracted?" The key for me, just as it is for all of you, including my cardiologist , risk assessment and developing an appropriate plan for monitoring the patient. BTW, the dentist that didn't have you sign the consent to X-rays is in violation of standard of care and likely many state dental practice acts.
Thanks for the comment Doug.
Adam
Very interesting post. And this fits nicely with the Sensible Med theme of questioning the yield of screening procedures in asymptomatic people. And also of how reimbursement drives procedures.
My dentist seems to offer/require films every 2 years. And as noted here, it’s always BEFORE the actual exam.
Dentists in my region (California) will not clean your teeth unless you agree to their x-ray schedule. For kids, dentists generally want to start x-rays at age 3. By age 7, most orthodontists insist on panoramic x-rays (and sometimes cephalometrics) just to monitor incoming dentition. Thank you for this important post -
Perhaps a sensible medicine post on the evidence behind dental cleanings is warranted. My last look found no evidence to justify these cleanings but it's been a while since I looked.
Thanks for your comment – this was a Cochrane review about recall intervals for oral health in primary care patients: https://pubmed.ncbi.nlm.nih.gov/33053198/
This says nothing about dental cleanings... only about "dental checks"... There are dental practices in the US who won't see you unless you're getting biannual "cleanings". Cleanings that make your teeth feel super smooth for two days and then it's back to the same teeth you had before the cleaning.
and here's an excerpt from a periodontist's response to my post
Valid point. Many dental practices treat by insurance benefits, since this requires so little cognitive effort by dentists or patients. If it’s cheap or free, why not? Imagine choosing your cancer therapy or whether to stent an MI based on insurance coverage. And yet, since dentists got in bed with insurers decades ago, this has become SOP. If you want a good dentist, choose one who is NOT contracted with your insurer. Then ask them to make the case for their recommendation based on health or your goals, not insurance benefits.
“More and more, I have become concerned about the radiation from medical radiologic procedures.”
You should. But do your homework and look up radiation doses from single intraoral images (periapical or bitewing). Most are in the 1 uSv range. Less than one day of background radiation from living your life. IMO this is a nothingburger.
https://open.substack.com/pub/theskepticalcardiologist/p/a-skeptical-periodontist-responds?r=1f2oz2&utm_campaign=post&utm_medium=web&showWelcomeOnShare=false
Haha. Here's an excerpt from my post on skeptical thoughts from the dentist's chair
"The hygienist introduced herself (we’ll call her Donna), put away her crossword puzzle book, guided me back to the exam room and told me that she was going to do an X-ray. I wasn’t asked if I wanted an X-ray or explained the purpose of it, but dental radiography now seems to be the norm. Perhaps I am given one every time I visit a dentist because I go infrequently, much less than annually, and dental insurance tends to pay for an annual X-ray. The dental offices probably assume if it is free, no sane patient will reject it.
More and more, I have become concerned about the radiation from medical radiologic procedures (see my discussion on the radiation from coronary calcium CT scans here).
The hygienists are always careful to put a lead apron over my groin and around my neck, which makes me feel a little better, but I can’t help but wonder…what is the yield of the x-ray in a patient with no symptoms, what is the risk of developing oral cancer from the procedure if performed every year? And what is the probability that something will be identified that is not really a problem, which may lead to more testing or procedures?"
https://open.substack.com/pub/theskepticalcardiologist/p/skeptical-thoughts-from-the-dentists?r=1f2oz2&utm_campaign=post&utm_medium=web&showWelcomeOnShare=false
I empathize with Adam’s internal discussion at every dental appointment about how firmly to refuse X-rays, because I have the same recurrent argument.
I am grateful for this careful essay, but I have a number of questions about the state of knowledge about dental X-rays that weren’t addressed.
What are the criteria determining low risk status for caries in adulthood - age? Number of previous restorations? Age of existing restorations?
What is the positive predictive value of an X-ray shadow in a tooth suggesting early caries?
What is the value of surveillance of such a tooth (perhaps with more X-rays?)
I’d also like to know the ratio of the number of dental X-rays obtained in asymptomatic patients to the number of procedures performed based on those x-rays.
In regards to caries risk, number of existing restorations is considered a risk factor. I like to consider 3 primary factors in my risk assessment: saliva, diet, biofilm which are all inter-related.
Most prescription drugs cause a significant decrease in quantity and quality of saliva as does mouth breathing and sleep apnea. Without the buffering and hydration of saliva, caries risk goes up. If diet is sugary and acidic in high frequency such as sipping and snacking, risk goes way up. Both of these lead towards a highly metabolic cariogenic biofilm which can take a while to correct even when diet is improved.
Thank you for your comments. The American Dental Association provides information about caries risk assessment and management, including their own risk assessment forms for ages 0-6 years and >6 years:
https://www.ada.org/resources/ada-library/oral-health-topics/caries-risk-assessment-and-management
Thank you for taking the time to send me to the ADA for more Information. Unfortunately, the ADA documents don’t answer my specific question. These answers are what would enable me to determine the usefulness of dental X-rays in common clinical situations. There is likely primary literature studying these issues.