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Many dental procedures lack scientific backing, data review finds

teeth cleaning
REUTERS/Mark Makela
Many dental procedures, from twice-yearly teeth cleanings to crowns for root canals, do not have a lot of rigorous scientific backing.

In a long-form article for the May issue of the Atlantic magazine, science writer Ferris Jabr describes how dentistry is “much less scientific — and more prone to gratuitous procedures” than most of us think.

The “truth about dentistry,” writes Jabr, is that “common dental procedures are not always as safe, effective, or durable as we are meant to believe. As a profession, dentistry has not yet applied the same level of self-scrutiny as medicine, or embraced as sweeping an emphasis on scientific evidence.”

“Consider the maxim that everyone should visit the dentist twice a year for cleanings,” he explains. “We hear it so often, and from such a young age, that we’ve internalized it as truth. But this supposed commandment of oral health has no scientific grounding. Scholars have traced its origins to a few potential sources, including a toothpaste advertisement from the 1930s and an illustrated pamphlet from 1849 that follows the travails of a man with a severe toothache. Today, an increasing number of dentists acknowledge that adults with good oral hygiene need to see a dentist only once every 12 to 16 months.”

“Many standard dental treatments — to say nothing of all the recent innovations and cosmetic extravagances — are likewise not well substantiated by research,” Jabr adds. “Many have never been tested in meticulous clinical trials. And the data that are available are not always reassuring.”

Disheartening conclusions

Jabr notes that Cochrane, a highly respected nonprofit global organization of independent scientific investigators, has been conducting systematic reviews of oral-health studies since 1999 — with discouraging (for the dentistry profession) results.

“In these reviews,” writes Jabr, “researchers analyze the scientific literature on a particular dental intervention, focusing on the most rigorous and well-designed studies. In some cases, the findings clearly justify a given procedure. For example, dental sealants — liquid plastics painted onto the pits and grooves of teeth like nail polish — reduce tooth decay in children and have no known risks. (Despite this, they are not widely used, possibly because they are too simple and inexpensive to earn dentists much money.) But most of the Cochrane reviews reach one of two disheartening conclusions: Either the available evidence fails to confirm the purported benefits of a given dental intervention, or there is simply not enough research to say anything substantive one way or another.”

“Fluoridation of drinking water seems to help reduce tooth decay in children, but there is insufficient evidence that it does the same for adults,” Jabr adds. “Some data suggest that regular flossing, in addition to brushing, mitigates gum disease, but there is only ‘weak, very unreliable’ evidence that it combats plaque. As for common but invasive dental procedures, an increasing number of dentists question the tradition of prophylactic wisdom-teeth removal; often, the safer choice is to monitor unproblematic teeth for any worrying developments. Little medical evidence justifies the substitution of tooth-colored resins for typical metal amalgams to fill cavities. And what limited data we have don’t clearly indicate whether it’s better to repair a root-canaled tooth with a crown or a filling. When Cochrane researchers tried to determine whether faulty metal fillings should be repaired or replaced, they could not find a single study that met their standards.”

Separate paths

Part of the problem, Jabr points out, is that dentistry and medicine developed separately.

“Most major medical associations around the world have long endorsed evidence-based medicine,” he writes. “The idea is to shift focus away from intuition, anecdote, and received wisdom, and toward the conclusions of rigorous clinical research. Although the phrase evidence-based medicine was coined in 1991, the concept began taking shape in the 1960s, if not earlier (some scholars trace its origins all the way back to the 17th century). In contrast, the dental community did not begin having similar conversations until the mid-1990s. There are dozens of journals and organizations devoted to evidence-based medicine, but only a handful devoted to evidence-based dentistry.”

“Dentistry’s struggle to embrace scientific inquiry has left dentists with considerable latitude to advise unnecessary procedures — whether intentionally or not,” Jabr adds. “The standard euphemism for this proclivity is overtreatment. Favored procedures, many of which are elaborate and steeply priced, include root canals, the application of crowns and veneers, teeth whitening and filing, deep cleaning, gum grafts, fillings for ‘microcavities’ — incipient lesions that do not require immediate treatment — and superfluous restorations and replacements, such as swapping old metal fillings for modern resin ones. Whereas medicine has made progress in reckoning with at least some of its own tendencies toward excessive and misguided treatment, dentistry is lagging behind.”

Ask about options

Jabr’s article is a fascinating read, and its general message — that many dental procedures, from twice-yearly teeth cleanings to crowns for root canals, do not have a lot of rigorous scientific backing — will likely surprise many people.


The article shouldn’t, though, discourage us from going to the dentist or following our dentist’s suggestions for oral health. But it does underscore the importance of making sure each dental procedure is absolutely necessary — and that all options have been presented to us — before we agree to it.

FMI: You can read the article on the Atlantic magazine’s website.

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Comments (8)

  1. Submitted by Paul Yochim on 04/22/2019 - 10:29 am.

    Susan, thanks for the article and the link. The referenced article mentions a lack of oversight on the procedures performed. What the article does not mention is the lack or absence of oversight of the sedation and general anesthetics in the offices that these procedures are being performed under. Many of the anesthetics are being performed by dentists with minimal training in anesthesiology while they are performing the dental procedure at the same time. The training that these dentists receive is not sufficient to be credentialed in a hospital like an anesthesiologist or nurse anesthetist would be.

  2. Submitted by Ray Schoch on 04/22/2019 - 10:35 am.

    I just finished reading the “Atlantic” article over the weekend. It’s important information.

    Having spent many thousands of dollars out of my own pocket for dental care over my several decades, I can relate to both the “ethical dentist” parts and the “unethical dentist” parts. I’ve experienced both. “Evidence-based dentistry” seems like an idea very long overdue, and its lack an unpleasant surprise for everyone, especially those trusting souls who’ve never questioned a dental bill, or who are fortunate enough never to have had to deal with any significant dental issues.

    Beyond the issues raised in the article, it seems to me worthwhile to point out that the vast majority of dental insurance policies – unless you’re affluent enough to be able to afford the premiums for a “Rolls Royce” plan instead of the economy car version – are not especially generous in their coverage. That’s a polite way of saying they’re woefully inadequate.

    My own insurance, which my dentist has pronounced to be “about average” in terms of its coverage, pays for the traditional 2 checkups per year (which the “Atlantic” article suggests may not even be necessary for many people). After that, it pays about 1/2 of the cost of whatever dental repair work needed if it’s fairly minor – such as a routine filling. Any repairs more elaborate than that will find patients digging into their savings accounts to pay for them. Having a crown installed or replaced can easily cost a patient $1,200 to $2,000, over and above what their insurance will pay for. Those extra dollars are coming from the patient.

    When a previous crown on a molar failed a couple of years ago, and the underlying tooth structure couldn’t support a new crown on its own, I ended up having to get a dental implant so I could chew on that side. My insurance covered none of the procedures involved – zero. From the oral surgery to remove the remains of the failed tooth to the implant itself to the new crown fitted to the newly-installed implant, that single implant ended up costing more than $5,000, and all of that expense came out of my pocket over the course of a calendar year. Readers who see ads on TV for “one-day replacement” of a mouthful of failing or defective teeth should know that the multiple implants involved could easily end up costing them $25,000 to $50,000, depending upon how complicated the procedure might be, and how many children the dentist involved is paying to send through college.

    • Submitted by Paul Yochim on 04/22/2019 - 11:38 am.

      How many children the dentist involved is paying to send through college? As a physician I find that to be an absolutely ridiculous and inappropriate assumption. Just like the patient who said that he paid for my Porsche. We don’t all drive Porsches and send our kids to Yale.

  3. Submitted by Paul Udstrand on 04/22/2019 - 11:38 am.

    I once went five years without seeing a dentist, and when I finally went aside from some plaque my mouth and teeth were discovered to be in excellent condition. I never go more than one a year. Oh, and I had “temporary” filling that never failed… many years later it’s still there.

  4. Submitted by Pat Terry on 04/22/2019 - 01:59 pm.

    I like articles like this. Makes me feel better about not going to the dentist very often.

  5. Submitted by Steven Bailey on 04/22/2019 - 06:47 pm.

    On two separate occasions with new Dentists (due to moving) I was very encouraged by them to get X-rays. I told them that I had just had recently had them at my previous Dentist and I would have them next time. As it was quite apparent the Dentist did not like this I agreed to bite-wings. On each of these occasions I was told the X-rays showed I had a cavity and they could take care of it right away. I told them I couldn’t afford it at the time since I had no insurance but we could take care of it next time. They tried to change my mind saying I could lose a tooth or end up needing a root canal but I said no. I did not go back to either of these Dentists. The following Dentists after getting new bite -wing X-rays said my teeth look great and no sign of decay. I never had those “cavities” 15 years later they seemed to have disappeared.

  6. Submitted by Darrell Pruitt on 04/23/2019 - 08:38 am.

    Shouldn’t we be warned that dental EHRs are less secure than paper dental records?

  7. Submitted by Michael Zuk DDS on 08/10/2019 - 12:19 am.

    Dentist OVER-TREATMENT is often related not to greed but to corruption of the continuing education programs. Imagine a dental lab running seminars that push full-mouth drilling approaches based on fringe science that often leads to patients getting mouth fulls of porcelain. Win-win for the lab and dentist but patients initially impressed with extra-white teeth often are left in pain and actually prematurely lose their teeth because of this fad. Ontario and Manitoba’s dental authorities recently banned ‘neuromuscular’ dentistry after decades of concern. Victims are beginning to connect on Social Media- this could be the profession’s largest breach of trust to date. Big Pharma messed up physician’s advice and dental labs and manufacturers mislead dentists to make them do the unspeakable. No more excuses.

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