Is Dentistry Safe and Effective?

The FDA may be too conservative but it does subject new pharmaceuticals to real scientific tests for efficacy. In contrasts, many medical and surgical procedures have not been tested in randomized controlled trials. Moreover, dental care is far behind medical care in demanding scientific evidence of efficacy. A long-read in The Atlantic spends far too much time on a single case of egregious dental fraud but it’s larger point is correct:

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. 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.

The joke, of course, is that there’s no evidence for the 12 to 16 month rule either. Still give credit to Ferris Jabr for mentioning that the case for fluoridation is also weak by modern standards–questioning fluoridation has been a taboo in American society since anti-fluoridation activists were branded as far-right conspiracy theorists in the 1950s.

The Cochrane organization, a highly respected arbiter of evidence-based medicine, has conducted systematic reviews of oral-health studies since 1999….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. 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.


If you want your wife to quit nagging you, you could just tell her directly.

I have seen both male and female dentists during my lifetime, and it has been my experience that male ones tend to recommend far more procedures than female ones. However that is far from a scientific study, and I would be extremely interested to know whether there has been any proper study as to whether such a bias exists.
People are driven by hormones as well as logic, and on average males are predators and females carers. I would seriously doubt whether many males consciously get off on their work, as suggested by the film The Little Shop of Horrors. However the effect could provide a subconscious nudge that would show up in a study.

People are driven by hormones as well as logic, and on average males are predators and females carers.

I'm wagering you don't know many of either.

That's what I implied isn't it? Note also the words "on average".

As a predatory male, I simply tell my densist no to superfluous recommendations.

Very good post.

I'd say there is a lot of accepted fraud in dentistry. They take unnecessary x-rays, replace fillings unnecessarily, always err on the side of something that is billable. And it is apparent that we can't expect the industry to regulate itself.

This seems like an appropriate case where a science grant from government for research would be indicated.

You've got lousy teeth. Deal with it.

I was talking to an equally old man who remembered dentistry in the 1950s and also education then. He agreed with me that we'd rather get the cane than dental treatment.

Such was life in Eisenhower's America.

As with medical care, the problem is that many people get dental coverage through their employers today.
The patient thus has no reason to question billable expenses, and so neither does the dentist. More expensive procedures often take weeks to negotiate between the dentist and the insurer, with the patient taking a back seat. But small things like replacing fillings, the dentist can just do it and bill the insurer and it won't be questioned.

Most dental insurance doesn't cover more than 50% of non-routine costs

Another reason why the graft is mostly in the routine costs - i.e. unnecessary filling replacements.

This just begs the question, why wouldn't the insurance company say something like "replace fillings, where's the evidence that fillings need to be replaced if there's not any evidence of a problem"

I've encountered a few people who have told me their dentist is having them replace filings because of 'mercury vapors'....which strikes me as suspect.

There's probably some small justification that shows up on an xray and the dentist can say it's preventative. Replacing the filling can prevent a root canal or crown later. It also might be too expensive for the insurer to try to litigate every filling.

You could figure out in a normal population X% of filings will end up causing a root canal or other problem. If a dentist, say, is doing two standard deviations or more than that, your reimbursement rate for replacement fillings goes down 25%. If you are doing less re-fillings without seeing more root canals, you get a bonus.

The dentist could come up with some rationale, such as the population they serve has more tooth problems, due to age, diet, socioeconomic status, etc. See public school teachers for comparison.

I doubt this is a problem. Insurance companies have plenty of data crunching power on their side. You could, for example, flag suspect dentists and require them to submit some additional diagnostic before approving replacing fillings, say xray images. If the claim is denied, they have to bear the cost of the additional xray. It would become clear very fast if the fillings are a racket or a good preventative measure.

They're like mechanics now. You have to always get a second opinion. We've had a dentist tell my wife she needed a root canal when she had no pain- other dentist said nothing about it. One dentist told me I had cavities, my daughter she had cavities, other dentist- not a peep.

In the USA, greed is good, hence scamming people is good. Government is in the pocket of powerful business interests.

The article, which I read on Thursday, pointed out that dental care is rarely covered by insurance; and even when patients have dental insurance, it rarely covers much of the cost. In other words, most dental costs are paid by the patients. It occurred to me that the absence of insurance for dental care and the exploitation of patients by dentists might be connected: there's no third party monitoring all of those expensive services, services that are not only unnecessary, but create the need for more dental services to fix the dental problems caused by the earlier unnecessary services. [For example, any invasive work on a tooth, such as a root canal, weakens the tooth, likely resulting in a cracked tooth later, which must be fixed with a crown or replaced with an implant, crowns and implants that don't last forever.] Does this article support the benefit, the need, for health care insurance generally, a third party monitoring providers that can't be trusted on their own? Consider the many instances of plastic surgery, which generally is not covered by insurance, where the surgeon performs so many surgeries on the same patient that the patient is disfigured.

... dental insurance seems more common in my experience than that suggests, and for routine stuff, it covers "most", more than "not much".

People I know without dental coverage usually just don't see a dentist, or go to a dental school or discounted program.

(How can a third party monitor "know" whether or not a root canal was "necessary" or "not quite necessary"?

Whether that black spot on the X-ray is "obviously" a cavity that needs immediate care or one that can be left for a year?

The honest problem seems to be more that dentistry is often fallible judgment, not pure science - and we have no obvious way to make it somehow be the latter.

Dentistry is less insured and less regulated than other US healthcare, so it's an interesting data point on sources of our healthcare problems.

Does the average person know that? I suspect most think of them all as "doctors"?

I don’t have the resources handy to prove this at the moment, but the fact is a very similar critique can be made for medicine.

Many fundental understandings about how the body works and tests and procedures turn out to be unsupported.

Ideas about brain blood barrier and gut biome are undergoing substantial revision. Tests like breast cancer screening as well. Just a couple examples from ready memory.

An instinct towards invasive tests and preemptive procedures and overreliance on medications etc etc is well documented

Here's a site that touches on what I am talking about:

It looks to be a decade old and could use updating for much recent literature on the replicability crisis and recent reversals of conventional wisdom.

Of course the over-prescribing of expensive imaging is well documented by now. There is less handy evidence on preemptive procedures that aren't actually supported by evidence.

I think a less hostile way to express your idea is some things are difficult to test by science. For example, the effectiveness of breast cancer screenings are not that easy to test if you are looking at results 10, 20 or more years out. Just consider a mammogram today is not the same mammogram from 2000. The effectiveness of a screening program is not just the machine but also the methods used to act on the results. Maybe in 2000 the philosophy was to cut out anything that seemed suspect while later they moved to a 'let's keep an eye on that' philosophy. Screening in one decade then isn't the same as screening in a different decade.

Well, sure, less hostile is generally good.

But after having experienced or witnessed my fill of defensive medicine, self referenced imaging, over-prescribed meds, and because-we-can preempitve procedures, I've become a little jaundiced.

Generally good, one would think. Not easy to test, though. Maybe aggressive is good if combined with better imaging and better ways to read the image. If you're trying to figure this out with only data as evidence, it's not going to be easy. It's going to be a bit of an educated guess.

'questioning fluoridation has been a taboo in American society' since Portland voters last rejected public water supply fluoridation in 2013?

'The joke, of course, is that there’s no evidence for the 12 to 16 month rule either. '

Cavities - who knows anything about them and their growth and development which would fit the rigorous standards that science requires, right?

I'm a bit curious. Maybe fluoridation mattered in an earlier age with less great hygiene. Today most people brush their teeth and it's not hard to get access to good quality toothpaste. On the other hand we slosh down a lot more sugar so maybe we need all the help we can get. Yet on the other hand almost everyone I know insists on drinking bottled water and aren't getting tap water into their body except indirectly, like from making coffee.

"Yet on the other hand almost everyone I know insists on drinking bottled water and aren't getting tap water into their body except indirectly, like from making coffee"

Bottled water is usually tap water.

(If in a place with awful* tap water, it's typically some other place's tap water, or filtered tap water, but it's still usually tap water.

* As in "tastes bad", not "actually unhealthy".)

I drink bottled spring water to avoid fluoride and bottled tap water.

What is the supposed downside to fluoridated water?

I should point out that whether it is science based or not, the German health care system provides for one free tooth examination per year. Which is useful to document in a 'Bonusheft,' as the health insurance company will provide a decent discount for something like crown work, which is not covered by standard health insurance. Almost as if the Krankenkassen feel that annual dental examinations reduce costs over the longer term, to the extent that it is a practice worth encouraging. But that is what happens in a profit driven, essentially universal health care system - the insurers have an incentive to base their coverage on empirical data, which is simple to classify and collect using a standardized reporting system that covers basically all doctors and patients, as the German electronic patient card is also essentially universal.

Do the Germans get to choose which tooth?

Probably not, socialists.

Good answer.

How long does the typical German wait to get that tooth filled?

Maybe 15 minutes - about the time it takes for the novocaine to work.

And if you crack a tooth (as in part of your tooth is gone), it takes maybe a half hour before getting a temporary plastic replacement - at least if it does not happen at night or a weekend. Then you will have to wait for a dentist office to open during normal business hours.

And of course, you can go to basically any dentist you wish - this town of 6,000 has 3 dentists, and they all accept basically any patient. Which means if you have a cracked tooth, and one is busy or closed (vacation, for example), you just go to another one - really pretty simple.

You are right - they don't get to choose.

They are forced to have all of them checked.

(Not sure what term would be better - dental check up?)

I'm inclined to think that flossing daily is useful since it removes bits of food that get stuck between teeth (even if you can't feel them). And now that it's theorized that gingivitis bacteria causes Alzheimer's it's probably a good idea to keep any level of gum disease far away.

I have heard directly from my dentist that the white amalgam material wears out faster and should not be used for biting surfaces. Metal fillings can last forever. And of course every time you get a filling replaced you loose a little more tooth material and get closer to needing a crown. So probably a good idea to only get white amalgams on visible areas.

Well hell.

My dentists have, over the past 4 years, been replacing my silver fillings with the composite. I got my forst crown and now I'm thinking it wasnt necessary.

They park their BMWs a block away in an alley so patients wont see them while agreeing to procedures.

I had a great dentist. Then we moved. The Atlantic article reinforces that I need to move on from these people.

Yes, I had that done 5-6 years ago (different dentist) and already had to replace one of the composite fillings. No double some of the silver fillings needed to be replaced (maybe 15 years old), but some probably would have lasted.

My extended family has lots of dentists (and doctors and lawyers). Many of them remove mercury fillings. But a Professor colleague of mine in Public Health said “I’ve had grants and teams trying to prove that mercury amalgam fillings are dangerous and I’ve not been able to do it. Nor have other researchers.” Interesting field.

I have a similar ophthalmologist(?) story. The Warden is a retired nurse and she is highly selective on health care providers. Once she told ours of another eye MD that drives a Bentley. He knew the man and was shocked. He wondered how many patients the guy saw each day.

I once escorted someone to an ophthalmologist because she thought that he may eject poison into her eyes to dilate the pupils and she couldn't see to get home. "On no, I don't do that" he said "I just leave her a few moments in a darkened room and then I can see into her eyes." He showed me the display in his machine, and yes he could.
It is a theory of mine that many of them subconsciously like patients looking at them though dilated pupils, which have the effect of making them think they (men or women) adore them.

The problem with the old metal fillings is that, over the decades, they can cause the tooth - especially a molar - to crack. But replacing them is not better since that weakens the tooth as well. Sigh...

Great post.

Add orthodontics to the list. It’s a racket. Every kid has been declared to have irregular teeth that need correction for some dubious medical reason, not just for aesthetics.

For those who don't quite get it, for a long time the dental profession was considered the lesser alternative for medicine, both in terms of status and income. That has shifted. Why? Because dentistry is health care primarily for the more affluent and is almost entirely cash pay. What do dentists charge? Whatever the market will bear. Is this a market failure? What I admire about dentists is how they have dealt with the absence of public dental care for the poor: no, rather than ignore the dental needs of the poor, dentists offer free dental care several times a year on an all-comers basis, not at a clinic but in a large public facility where the "patients" line up by the thousands. Why didn't medical doctors do that? They didn't have to, Medicaid (and Medicare) providing reimbursement for the effort. As for the cash pay patients, why do they pay such high fees for services that are often unnecessary? In part, vanity. Smile!

What do dentists charge? Whatever the market will bear. Is this a market failure?

Median cash compensation for general dentists is currently about $150,000 per year. About 90% of all dentists are general practitioners. That for pharmacists is about $125,000 per year. That for optometrists is $112,000 per year.

The least handsomely compensated medical specialty tracked is internal medicine, for whom median cash compensation is $194,000 per year.

Compensation paid to dentists accounts for charges amounting to $183 per household per year. I've never received a dental bill exceeding $500 or ever heard of anyone financially ruined by charges for dental work. There's no analogue of Jarndyce v. Jarndyce in the world of dental care.

My feeling is that dentistry and eye care work a lot better in terms of outcome and cost than other types of medical care.

I can speculate about why this is, but eye and dental problems get fixed in durable ways for modest cost. Real medical problems sometimes get fixed in a durable way ,(Cardiac bypass surgery) or not , (back surgery) but in both cases, they are orders of magnitude more expensive than the most heroic dental procedures, or Lasic.

If folks only knew how different ophthalmologists treat the same eye condition.

I think I would put ophthalmologists who do medical treatment to eyes in with general medicine. I mean the ophthalmologists who do Lasic and write prescriptions for glasses and contact lenses.

During my adolescence my dentist prophylactically drilled and filled all my molars, resulting in weakened teeth. Neither of my children have endured this, so there’s some progress. On the other hand, my niece was injured by a drilling mistake that created an abscess in her cheek. The dentist demanded that she sign a document absolving him of any responsibility. She did not. I looked up the dentist in the state license registry. He has moved multiple times from state to state, and has multiple complaints against him in this state. Yet he still practices. The most amazing fact alleged in the article: regular brushing can promote the self-healing of a small cavity. Has any dentist told any patient this? In my near 7 decades I’ve never heard it.

When I lived in the UK, I went for a cleaning and the dentist told me not to come back for two years, saying anything more frequent than that was unnecessary given the good state of my teeth. Fast forward six months, I'm back in the US, where I'm back on the 2x/year regimen and between insurance providers. The dentist tells me I have six cavities that need to be addressed immediately. I left the office and haven't been back in two years, with no dental issues whatsoever.

As a teenager, I needed my teeth straightened. We went to my family dentist/orthodontist for a consultation and GTFO of there when he suggested knocking out four of my teeth, breaking my skull, and moving the front of my face back to correct an overbite.

I've been skeptical of dentistry ever since.

This story has a happy ending. We ended up finding a good orthodontist who did a great job and now I have a great smile. I seldom see a dentist; I haven't been in years. I brush, floss, and swish twice daily and I've never had a cavity, not once, in my entire life. The last few times I've been to the dentist, their jaws have literally dropped when they discover a middle aged man that's never had a cavity.

Maybe I'm just lucky.

"Maybe I'm just lucky."

Could be, my story is similar. But my mother put fluoride drops in our juice and milk when we were kids, until the city started city-wide fluoridation. So I've probably got life-long stronger teeth as a result.

Meanwhile the voters in Portland, OR infamously vote down fluoridation repeatedly, and have a higher-than-average rate of tooth decay (notice that even the skeptical studies that Alex cited admit that fluoridated water reduces tooth decay in children).

I had a similarly bad dentist at one point. He was constantly ordering extra x-rays despite my teeth having no cavities nor fillings, and he recommended that I get my wisdom teeth pulled despite them having no crookedness nor cavities.

That seemed like a BS recommendation, fortunately a friend knew the former dean of the local dental school so I got a special appointment to see him. Basically as a favor, the guy still had his clinic but didn't seem to have any patients or staff (his wife was his assistant during my visit).

The expert dentist said nah don't let them take your wisdom teeth out. I was fully adult and those teeth were fully in place so to remove them would've required not just breaking the teeth but breaking my jaw as well.

Best dental visit that I've ever had, that former dean was smart and able to communicate clearly but without patronizing. And gave much better advice than that other shyster (or whatever we call corrupt) dentist.

Who I stopped seeing, and I stopped seeing dentists in general.

I know someone personally who has good teeth and who has never been to a dentist. I also know of someone else anecdotally who was in the same situation.
The "Me Toos" on this blog seem to add up to something, although whether it can be authenticated in a rigorous scientific manner as seem to be implied by the lead article remains to be seen.
I had a magazine in the days of paper where a maverick but qualified dentist who wrote books with titles like "How to Become Dentally Self Sufficient" used to offer articles. A practising dentist wrote a review which rubbished the aforementioned title.
I recall Independent Television News (in the UK) running an anti-dentist story some years ago complaining that they drill into people for power and money. It more or less said the same thing as the bulk of this blog.
The problem seems to be pre-symptomatic treatment. Is it justified?
One thing that makes it appear justified is the fact that one cannot get emergency dental treatment quickly and easily "as of need". Already overworked hospital emergency departments are the dustbin into which all this and other minor ailments all the way up to major heart attacks and strokes are shovelled. Hospitals are often placed in difficult to access locations and are surrounded by crowds of desperate people. Even ambulances can not get through and end up queuing instead of going to the next call.

"Little medical evidence justifies the substitution of tooth-colored resins for typical metal amalgams to fill cavities. "

Did anyone ever suggest that was a medical issue, not an aesthetic preference on the part of the people getting the fillings?

My dentist never presented one as medically preferable to the other.

So, Alex, why has the market for credible dental research failed, and what would remedy that?

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