Category Archives: dental visits

Skeptical Thoughts From The Dental Chair: Part 2, Are Routine Dental Cleanings Beneficial?

In Part I of this series we listened to the skeptical cardiologist’s seemingly paranoid thoughts questioning the risk/benefit ratio and value of things that dentists do.

One such thing is the routine 3, 6, or 12 month visit for teeth cleaning that has been recommended by every dentist I’ve ever seen, and was vigorously defended by my current dentist (actually, he deferred the defense to his assistant). Exactly what is done at these sessions apparently varies widely and has widely varying names.

A 2015 review of the topic in The Journal of Clinical Periodontology likes to use the term  professional mechanical plaque removal for the various processes involved:

“This may include scaling or polishing teeth (or both) at supragingival locations, subgingival sites or a combination of each. Oral hygiene instructions (OHI) for personally performed mechanical plaque control may be an integral aspect of this intervention. Thus, the term PMPR covers a heterogeneous group of procedures but excludes deliberate root planning or root surface debridement.”

The lead author, one Ian Needleman, works at the Unit of Periodontology, UCL Eastman Dental Institute, UCL, London, UK.

After reviewing the best evidence available (from randomized controlled trials, RCTs), the authors concluded:

The strongest findings from this review are that professional mechanical plaque removal (PMPR) when combined with oral hygiene instructions (OHI) results in a greater reduction in plaque and gingival bleeding than no treatment. However, there is no evidence of a difference in the effect on plaque and gingival bleeding comparing PMPR combined with OHI versus OHI alone when OHI is both thorough and repeated, that is there is no additional effect of PMPR on plaque and gingival bleeding above that gained from OHI where PMPR has initially been provided.

Yep, you heard that right. The dental cleaning you’ve been suffering through all your life adds nothing to the oral hygiene instructions (brush your teeth twice a day, floss once a day) and presumably the home daily oral hygiene that results from those instructions.

Furthermore :

A striking further key finding for these comparisons remains the lack of data investigating prevention of periodontitis.

Correct. There are no studies that PMPR prevents periodontitis.

A brief discussion from the NIH website on gum disease is helpful here:

Periodontal-Disease-Trailhead-DentalWhen gingivitis is not treated, it can advance to “periodontitis” (which means “inflammation around the tooth”). In periodontitis, gums pull away from the teeth and form spaces (called “pockets”) that become infected. The body’s immune system fights the bacteria as the plaque spreads and grows below the gum line. Bacterial toxins and the body’s natural response to infection start to break down the bone and connective tissue that hold teeth in place. If not treated, the bones, gums, and tissue that support the teeth are destroyed. The teeth may eventually become loose and have to be removed.

The periodontal review paper concludes:

  • There is most likely no value in providing PMPR without oral hygiene instruction. Repeated, thorough oral hygiene instructions for personally applied plaque control appear as influential as PMPR on periodontal health.

  • PMPR might achieve greater patient satisfaction with treatment. The impact on adherence to care might be important.

  • Although more frequent PMPR favours greater health gains for surrogate outcomes of prevention, there is little to guide the frequency of PMPR applications. This should therefore be judged by a needs and risk assessment although such an approach should be tested in a rigorously designed study.

A 2013 review by the Cochrane Collaboration came to similar conclusions (Cochrane review periodontal PDF), finding only one acceptable study comparing “scale and polish” of the teeth to no “scale and polish” and concluding:

This study showed no evidence to claim or refute benefit for scale and polish treatments for the outcomes of gingivitis, calculus and plaque.

A search of the website of the American Dental Hygienist Association, including the section entitled “evidence-based practice recommendations,” fails to find any support for routine dental cleaning.

To be clear, the question asked is: is there any benefit to performing the PMPR on patients with no evidence of gum disease?  If you have chronic periodontitis, then a  2015 review from the American Dental Association (ADA ) concludes that there is moderate evidence that scaling and polishing is helpful, improving the amount of clinical attachment of gum to teeth by 0.35 mm. There are no studies showing that it prevents tooth loss.

Screen Shot 2016-03-26 at 9.31.56 AMIf your gums are fine and you want to start skipping the “scale and polish” two Cochrane reviews suggest that powered toothbrushes do better than manual toothbrushes at plaque removal.  I promise, that is all the oral hygiene instruction I am providing.

Misinformation in a graphic from NJSmiles of Ramsey. This theory is no longer believed valid but it makes for nice scare tactics. If losing your teeth doesn’t worry you, how about heart attacks and chronic kidney disease?

Finally, the theory my dentist put forth that gingivitis or periodontitis causes heart disease or coronary artery disease has not been proven. Check out this NPR story or this statement from the American Heart Association for more discussion on this topic.

Stay tuned for Parts III and IV of the skeptical questions about dentistry in which we examine the risks of disease transmission and the role of dental radiography.

Gingerly Yours,



Skeptical Thoughts From The Dentist Chair: Part I, The Questions

The Skeptical Cardiologist found himself lying in a  dentist chair one day having his  teeth poked, prodded, scraped, rubbed and polished, when fears of the adverse consequences of these procedures suddenly overwhelmed him.

Previously I had considered routine dental cleaning a necessary annoyance, something that I guiltily avoided, primarily because of the time wasted and discomfort associated with it. But as I lay with my mouth open, a series of questions erupted in my consciousness.

Perhaps this anxious skepticism was related to the writing and thinking that I have done about the downsides of routine annual electrocardiograms or routine stress testing after stents. It has become clear to me that the risk/benefit ratio of any annual medical evaluation should be questioned.

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?

These concerns are similar to ones that we face daily in cardiac testing (and for PSA and mammography), but unlike stress testing and breast cancer screening, there seems to be little scrutiny of the value of the routine annual dental x-ray.

Donna placed a bib around my neck and I noticed that she was wearing medical gloves and that she was preparing a device covered with plastic to stick in my mouth. That’s nice, I thought, good sterile technique! However, adjacent to the part of the device covered in plastic, was metal that was uncovered and I saw her touch that, then manipulate the plastic and put that in my mouth.  I began worrying about transmission of hepatitis or HIV virus from a previous patient which was now being inserted into my mouth.

I began thinking that if one case of hepatitis is created by a routine dental visit, that probably negates the benefits, if any, of the thousand patients that had their teeth cleaned and didn’t get hepatitis.

After irradiating my teeth for unclear reasons, Donna began preparing her pointy metal probes, picks, and claws for the “cleaning.”

As she began picking, clawing and scraping away at my teeth, I began to wonder if this could be more harmful for me than helpful. What if this process was somehow damaging the enamel of my teeth and making it more likely that I would have problems?

I worried about my tongue: what if it I wasn’t positioning it in the right spot? Could it be hit by one of her picking devices, causing me to bleed, which would then cause the multiple bacteria now swarming in my saliva to gain entry into my bloodstream, perhaps landing on a heart valve and causing an infection, endocarditis, that would then result in a need for valve replacement surgery?

Periodically she would squirt a liquid into my mouth and then ask me to close my lips around the plastic sucking device. How well had the sucking device and the squirting tool been cleaned before the last patient and how I could I possibly verify this? I had to put my complete trust in this dental hygienist who I had never met before. I didn’t know what her training was.  I didn’t know what her level of compulsiveness with regard to germ transmission was.

Did I want her to be very aggressive with the cleaning or superficial? Which was better? Previously, I have had both approaches and I’m usually thankful for the brief, superficial variety.

Donna announces that she will be “polishing” my teeth and the dreaded rotary brush, coated with nasty paste is applied. What are the component of the paste? Is it likely to fly off into my lungs and set up a nidus for an inflammatory nodule?  If I swallow it will its toxic contents be absorbed into my blood stream and destroy my liver?

At the very instant that she is done, the dentist enters the room and greets me with a hand shake; he is an affable, fifty-something fellow in  casual dress. I have revisited this dentist a second time because he didn’t find anything amiss the first time I visited him.

I have an intense distrust of dentists, as I have found their “cavity detection rates” differ wildly. (I went to the same dentist in Louisville for 5 straight years and he gave me rave reviews about my teeth. My first visit to a different dentist (highly recommended by a mysophobic ex-wife), resulted in the identification of several (asymptomatic) cavities and subsequent fillings – the first cavities I had had in twenty years. I left her and went back to the guy who never found cavities. (Interestingly, one who studies cavities is termed a cardiologist).

Donna told me that I have some build up of tartar. I ask her to define it and she tells me tartar is plaque on the teeth that has become calcified. I ponder the similarities between the development of calcified plaque in the coronary arteries and the teeth. About ten years ago cardiologists felt there was a connection between ginigivitis and coronary atherosclerosis, possibly mediated by inflammation, but this has mostly been discredited.

I ask Dr. Watley what the significance of tartar and plaque is. He seems a little taken aback and launches into a description of what “some say:” bacteria build up in the plaques around the gums and launch themselves into the blood stream,  landing on heart arteries, pancreas, and spleen.  At first I think he must have forgotten that I am a cardiologist, but then he asks me what I think of his theory;  I tell him there is little scientific support for it. He admits that his other cardiologist patient doesn’t believe it either.

I ask him what the value of a routine cleaning is.  He says “Donna, what do you think? Donna, clearly nervous, talks about preventing bacteria from building up.

I ask “Is there any evidence that annual cleaning is better than another interval?” He says that those who get cleaning every 4-6 months do much better than those who don’t. No doubt!!!

Dentists, like cardiologists, benefit financially from having exams done on a regular basis.  It’s hard to get unbiased information from your dentist or cardiologist, or an organization run by dentists or cardiologists, on the value of routine cleaning or cardiac testing or the frequency at which examinations or testing should be performed.

In Part II of this post, I’ll present the scientific evidence, if any, to answer some of the questions I’ve posed above.

Despite my distrust of dentists, I want to make it very clear that I am not a RABID anti-dentite.