Surprisingly little evidence for usual wisdom about teeth | Hacker News Reader

Surprisingly little evidence for usual wisdom about teeth

nytimes.com

160 pointswallace_f183 comments

Anecdotal comments, in my opinion, are particularly unhelpful when it comes to dentistry. Many people have teeth prone to all kinds of problems despite perfect hygiene and brushing. Others have, essentially, indestructible teeth. The last time I went to the dentist was 27 years ago. I was told I had three cavities that needed filling. Never got it taken care of. Nearly 30 years later, teeth are working great. But, like I said, I don’t draw conclusions from this as there are others — apparently — who brush twice a day, see the dentist regularly, and nevertheless have a mouthful of problems.

> The last time I went to the dentist was 27 years ago. I was told I had three cavities that needed filling. Never got it taken care of. Nearly 30 years later

Explain the math here? You went to the dentist 27 years ago but now you are rounding up to 30 years later?

Actually a larger point. How do we know (we don't) that you were correctly diagnosed as having three cavities that needed filling? Maybe the dentist was just an opportunist and you didn't even have any cavities? Or (someone who knows dentistry better can comment) there is a state whereby it could be considered a cavity but not such that it definitely needed to be filled?

Wouldn't that opportunist mindset go against the oath you pledge when you become a doctor?

The pledge does not matter as much if you got five kids to feed.

https://www.youtube.com/watch?v=_dhjmSp30jc

27 years ago is nearly 30 years.

I apologize for the lack of mathematical precision.

Using a precise number within two sentences of a rounded number is utterly inexcusable. I have nothing to say for myself. It was a contemptible and inexcusable mistake and I am going to voluntarily suspend myself from HN for 27 hours.

My sister and I are like you. We've both taken somewhat spotty care of our teeth over the years and never really had problems. I've never had a cavity, never had gingivitis. I do get plaque, but I just scrape it off with one of those dental picks.

A long time ago, a dentist we had told our parents we had good mouth bacteria or something. I don't know how true this is and I don't put much credence in it, but interestingly enough, the only time in my life I had any kind of gum problems was when I was regularly kissing someone with constant tooth problems. It went away after we broke up and i haven't had problems since again. Again more just a little side note than anything scientific or would recommend basing decisions on.

Do you find this to be true of many health related things as you get older? I know 80 year olds who do literally everything doctors say not to (red meat makes up most of their diet, they drink tons,they smoke or smoked for most of their lives, breakfast of 3 eggs and bacon almost every day) and then I've known people who didn't make it to 50 that looked like bruce lee and lived ultra healthy lives that managed to get lung cancer or pancreatic cancer.

It sometimes seems like life is just a game where you can min-max your stats if you want but RNG rules in the end.

There has got to be some research group out there looking into this sort of phenomenon - people who take great care of themselves yet have lots of medical issues and on the other end of spectrum people who do little in the way of living healthily yet live to a very long age devoid of ailments. We've all seen this anecdotally, at least.

Do you think stress levels are a factor that typically go unstudied that play a part in these things?

Gut-brain connection? Just good genes?

The way we're all bombarded with all kinds of health-centric information of varying integrity these days one would think someone is studying this in a massive way with very large trials across varied populations.

On day its TMAO[1] in red meat the next day its something else. Surely someones studying all of this as a whole, right?

[1] Teasing Out the Role of Red Meat and TMAO in Cardiovascular Risk

https://consultqd.clevelandclinic.org/teasing-out-the-role-o...

I remember when someone wanted to study Ozzy Osborne as an example of someone who abused themselves but is pretty healthy (https://abcnews.go.com/Health/Wellness/genetic-mutations-ozz...)

So I'd like to think someone is looking at the things you mention. Someone should study my wife's grandparents, BBQ and 7&7s are their way of life and they're as spry as can be

A lot of the people who take care of themselves are following bogus advice (though it is/was often considered the gold standard at the time they followed it - salt reduction is mostly harmful, many eggs/day are mostly helpful, etc)

So it’s really hard to draw any conclusion from these cases.

Right? Ha. My dad won't exercise, he says you see old guys working out and then they die of a heart attack. He would rather just relax. My grandfather had full denchers (age 94). Watching him brush his teeth in the sink and leaving them in a cup on the counter to soak/clean didn't seem half bad.

I have largely stopped trusting dentists, unless I have pain. When my lifelong dentist fell out of network I went to a new dentist and they pushed all kinds of procedures and nonsense, saying I needed 3 fillings, etc. I've been to another dentist and they said things completely different. I don't understand how two professionals can draw polar opposite conclusions. It really seems they recommend needless procedures to fill their books of business and fleece costumers.

It's visible cavities and decay, it's not like you're diagnosing based on symptoms someone is describing to you, which I can understand for general doctors or specialists drawing blanks or different conclusions.

Those pokey things the stick in your teeth were found to create pockets in your teeth where bacteria can hide and actually cause cavities.

Source: a dentist.

You mean the pokey things a dentist holds when he's exploring your mouth? :)

Yes. Looks like Wikipedia confirms, so don't let dentists probe your teeth! https://en.m.wikipedia.org/wiki/Dental_explorer

" Some dental professionals have questioned this practice in the first decade of the twenty-first century.[1][2] The use of a sharp explorer to diagnose caries in pit and fissure sites is no longer recommended and clinicians instead should rely on "sharp eyes and a blunt explorer or probe." Penetration by a sharp explorer can actually cause cavitation in areas that are remineralizing or could be remineralized. "

  I've been to another dentist and they said
  things completely different. I don't 
  understand how two professionals can draw 
  polar opposite conclusions.

Isn't there some kind of solution for these sort of diagnostic aberrations or difference in medical opinions?

I know they have tumor boards for cancers and such where they try to arrive at a consensus plan of treatment for an individual patient.[1]

Surely there are such solutions for dental / other medical issues, right?

Somewhat tangential from all this, I'm amazed that in this day and age we still have such a hit or miss approach to treating patients. Its mind blowing how little our medicine has advanced in some aspects despite cutting edge innovations.

[1]

What Is a Tumor Board? An Expert Q&A

https://www.cancer.net/blog/2017-07/what-tumor-board-expert-...

An old acturian at my current job usually tease new developers that they are just like dentists - never satisfied with anyone elses work and always suggesting serious rework that is critically important.

Living with a dentist I learned that the single most important factor (by far) in the health of teeth is the genetic factor. Some people do not brush their teeth for years, never floss, have bad diets, etc. and still barely have a cavity. Others do it "by the book" and yet their teeth are a ruin. This is not to say that brushing teeth or flossing won't help. It will just not compensate if you pulled the genetic short straw.

But as in every job dentists also feel pressured to point out other people's lack of quality work to promote their own. You'll see this in the IT guy who immediately recognizes that whatever the previous one did on your computer was amateurish and they can do it better, same with the electrician, the plumber, the mechanic, the plastic surgeon, etc.

I often dream of having a bunch of experts in any field in the same room answer some kind of basic question.

After college I worked at the computing lab. Someone started to talk about OOP. One dude said that OO was one thing; the other contradicted saying it was another thing. They started to debate about what said things were really .. they never reached any sort of conclusion.

Medicine isn't different. Sometimes I think we need a 2-tiers doctor meeting where you can have at least 2 different opinions in one go.

My litmus test is what a new dentist says about my wisdom teeth (I have all four).

Please share what you expect a good dentist to say

not: "we should make a plan for removing these"

I don't take particularly good care of my teeth: I brush in the morning when I remember, maybe 4 days/week on average. I floss about as often. I've never gotten a cavity or had any problems at all, and I'm 31.

Similar. I stopped going to the dentist 26 years ago. Never had cavities since my adult teeth came in, never brushed, never flossed (except to get stuck things out). I moved around a lot, so getting another dentist fell by the wayside.

I've gone through a lot of diet changes over the years. I used to consume tons of sugar (multiple chocolate bars & 3 cokes a day), later tons of fast food, then healthy food, then mostly vegetarian & low carb & next-to-zero sugar or sweeteners. Never had a cavity throughout all those phases.

> never brushed

Ummmm Have you noticed that people tend to keep their distance when you talk?

Actually, no one has ever done that.

Bogus headline, article confirms basic beliefs are true:

> brushing with fluoride toothpaste that matters, not the brushing alone. Doing that doesn’t just prevent gingivitis and plaque formation; it also prevents cavities, which is the outcome that we care most about.

> powered toothbrushes reduce both plaque and gingivitis more than regular toothbrushes

> toothbrushing with flossing versus toothbrushing alone most likely reduced gingivitis, or inflammation of the gums

Article seems to miss that gingivitis is a bigger concern than cavities for adults

I guess people wouldn’t click on “Most of the standard advice about dental health is spot on but there’s some doubt around the edges.”

I wonder how many people will toss their toothbrushes after only reading the headline and develop problems as a result. Seems like journalistic malpractice.

> Seems like journalistic malpractice.

It's not 'malpractice' and it's a mistake to think that what you consider journalism is anything other than a vehicle to sell advertising in the end. There seems to be this assumption that what is written (especially and actually in the NY Times (which I do read and pay for)) is pure and good and the people writing spend untold hours to get the story right and fairly balanced. My anecdote is when I was interviewed a few times in the past by the NYT the writer fed me conclusions and it was very easy to figure out what to say in order to get my name printed. (A contrary position to the point and stated vehemently was almost certainly the way to go..)

Obligatory: https://medium.com/@addictiondocMD/a-new-corollary-to-the-ge...

It's concerning to me how prevalent this seems to be in a number of Very Important news memes we've been listening to for the last several years.

This piece while interesting does not seem to differentiate mainstream articles vs highly specialized fields when it compares both in terms of accuracy.

I would bet it's not only profitability but also ROI that dictates how long a paper can part with a journalist for his investigation in a story before it becomes too much time in the eyes of management; the highly comprehensive piece does not bring that many more readers and possibly even less if the topic at hand is very specific.

As well politics on the other hand are dealt with on a daily basis and accuracy can more easily be measured even by the mainstream reader unlike a highly specialized field.

True, but in this case the information the newspaper got from the "expert in the field" source is also flawed. So I guess it's different than the normal case where the journalists get it wrong, but the end result is the same and the rule of thumb remains: whether the topic is dentistry, politics, or something else, don't be too sure that the "facts" you're reading in the paper are actually facts.

You’re talking about what is. I’m talking about what should be. It’s not somehow ok to harm people in the pursuit of advertising money just because it’s the norm.

> I’m talking about what should be.

What about journalism to you means it should have some kind of a higher calling? The people working in that industry have jobs and families to feed. If they simply did the right thing they wouldn't be employed very long if their competitors didn't follow the same path.

When 'journalists' write either left leaning or right leaning pieces are they being circumspect and covering all angles with fairness? Or are they just making sure they have food on the table and/or ensuring that readers continue to patronize the paper (or broadcast) that they work for?

It's nice to think that someone else who has to earn a living and feed their family should be 'above it all' but in reality that is never going to be the case.

Maybe a better idea is to teach children in school over and over that what you read and what is reality are two different things. Don't believe what you read.

You could write almost the same thing about doctors, yet we have no problem using the term “malpractice” with them, to the point that it’s just assumed you mean medical malpractice if you don’t qualify the word.

Doctors take an oath and it is very clear what they are expected to do. (Some of them stray of course but it is atypical). Additionally 'Physicians' (if that is what you mean by 'Doctors') are a more homogeneous and generally trustworthy group than 'journalists'.

I believe that it is the case when we should not lower the level because stupid people exist. My anecdotal experience with medicine is the experience of the doctors making decisions about my body use by themselves, being unable to support my decision making process by their expertise. I suppose it is due to the reasons listed in the article discussed. Doctors rely on unscientific knowledge (it is ok, when there are no scientific knowledge) and lack a mental discipline to demarcate in their mind scientific and unscientific knowledge. So when I start answer questions, like "if I have been riding my bike for 10 years already and there is no retina detachment, might we see it as an evidence that all is ok and a retina detachment is an unlikely outcome in my case", the doctor asked cannot say nothing of importance. All she could is to continue to insist that I should abandon my bike. But it is not her decision, it is my body, so it is my decision. I asked about physiological mechanism behind a retina detachment, to understand it and to be able to limit my physical activities, to find a compromise between no physical activities and retina detachment. She was unable to answer my questions.

Why? Because her knowledge is tribal ritual knowledge, not a scientific one. Her knowledge is a bunch of rules in a form "if <symptom> then <treatment>". Completely useless knowledge for my decision making process.

So it is a good thing when mass-media brings an attention to this sad fact. We need to bring an attention to this, to make medicine to think big phylosophical questions and to change itself. On the way of this we can damage people with a bad decision making process, who could stop brushing their tooth because of headlines. It is bad, but there are upsides of that: next time when they come to a dentist, they will get an evidence that their decision making process is not perfect. So they will be able to learn something. To my mind, a couple of teeth as a payment for an improved decision making process is a good deal.

I’m not sure if I’ve understood this comment properly. Are you saying that it’s ok if the headline is full of shit, because it serves the more noble purpose of getting people to trust their doctors less?

I see it differently.

1. It is not full of shit, there are only one word in a phrasing that makes the headline misleading. It is "surprisingly". In medicine there are nothing surprising when there are not enough scientific verification for a conventional wisdom. And yes, I'm ok with it.

2. It doesn't serve the purpose of getting people to trust their doctors less. If someone do it the wrong way, the reality would fix it anyway. It is a good outcome. People would learn how to do decision making, doctors would be forced to rethink ways they persuade their patients that doctors know better. It is more contraversial, I agree, but I can live with it. Why should I have less information I need, if someone cannot deal properly with information of this kind?

You know, I'm riding bike as I rode before despite of risk of retina detachement. I decided that 10 years of riding is good enough evidence for me. When I have no access to a scientific knowledge on topic, I have no other options except to fall back to use an anecdotal evidence. In any case I'm not going to through out my bike, I like it and I believe that psychological health is more important than physical.

I don’t understand #1. The article itself says that there’s plenty of evidence to support the basic dental wisdom of brushing and flossing regularly and getting regular checkups. Or are you arguing that the headline is correct and the content of the article is wrong?

There are a lot of evidence about brushing, and only brushing. Article admits it. Flossing is more contraversial, and the best argument is about problems that could arise decades later: this argument not just a rational argument for flossing, but also explains the weakness of scientific evidence. It must be hard to make a longitudal research while controlling subjects for flossing, I can understand it. But it doesn't mean that there are a lot of evidence, it means there are plausible excuses for a lack of evidence. I see this distinction as an important one.

(At the same time I acknowledge, that article doesn't express it in such a wording, it does it more vague, leaving some crucial information behind links and stressing the point of lack of evidence, to justify the headline. It is clumsy.)

Also in the article mentioned yearly X-rays, frequency of brushing, scaling and polishing, bonded amalgams, interdental brush, preventive visits. Not every in the exact sense that "little evidence found", and I didn't bother to visit the all linked articles to see what is there, but nevertheless, I want to point, that brushing and flossing is just a part of the article.

In any case I see that the headline is good enough. After some thinking I even do not see "surprisingly" as a redundant word: surprise is a subjective feeling and the author can be surprised when I'm not. Moreover I guess that not only the author was surprised but some of his readers also.

edit: typo

The headline seems pretty accurate, it says "surprisingly little evidence," which is more than none.

Important to note that little/no evidence doesn't mean it's false, it's just that it hasn't been (rigorously) studied. When the flossing story came out a couple of years ago (no evidence that flossing is good for your teeth), the headlines jumped on that and distorted the fact the it was just that it hadn't been studied, not that it didn't have an effect.

There are surely cases where something is so bleedingly obvious no one has thought to do a peer reviewed study of it. Then there are things long assumed and just part of standard procedure in the same category that are worth a bit of rigor.

Well, I am quite aware that lack of evidence does not always mean a thing is not true; but I do prefer to have some evidence to go with claims, especially when they directly affect my day-to-day.

Dentist here, AMA

By the way: - there is scientific evidence in dentistry just like any other branch in medicine - there are good and bad dentists just like in any other profession - the good ones tend to be very scientific and evidence-based (I know I am, everything I recommend and do is based on solid evidence, and I provide links to pubmed to any patient that asks for information) - a good dentist should be able to answer any of your questions or doubts in a split second, I often draw simple sketches to explain concepts to patients - please use your common sense: even though it might be hard to prove with 3 standard deviations that flossing makes a big difference (for all sorts of reasons that statisticians know very well, including the difficulty of tracking a large group of patients), it's pretty obvious that removing rotting food from your gums is good and leaving it there to putrefy is bad, don't you think? same goes for all the other claims...a powered toothbrush is better simply because it does more iterations per minute than a manual one...again, common sense

I stopped using a powered toothbrush because:

1. my hygienist said it made no difference in plaque formation on my teeth (I did A-B experiments)

2. I was concerned it was abrading the enamel.

I'm old, btw, and am mostly concerned about receding gums and bone loss. I brush, floss, use the pipe cleaners for between teeth, and run one of those pointy rubber things along the gum line, and still get gingivitis. My dentist says there's nothing more I can do about it.

I've also tried various mouthwashes, which made no difference.

Anything else I can try?

Have you tried SmartMouth "DDS strength" mouthwash and toothpaste by chance? It contains a zinc formulation that inhibits baterial growth. So far, it's the best I've come across.

I did try a prescription-only DDS mouthwash. No difference.

> I was concerned it was abrading the enamel.

Teeth are pretty hard on the Moh's scale relative to bristles. If you're abrading enamel, it's from something in the toothpaste (which has all kinds of mineral abrasives), or tooth-tooth contact from chewing/grinding.

1. the powered ones do more "swipes" per minute, so in general they tend to be more effective. If you're good with a manual brush, you will most likely get the same results

2. enamel is far too strong to be abraded by the brush, what does get abraded is the dentin (the yellowish part closer to your gums, that's why sometimes you can see small dent-like abrasions there) so try to focus on brushing softly in those areas. A good idea is to use soft bristles

All you do is good and you're probably already doing 95% of what can be done, the other risk factors are smoking, female hormones, stress and diet. If you are not stressed, don't smoke, are male and eat mostly plant-based whole foods you can't do much more than that

Can you point to the research on the “mostly plant-based” part?

https://nutritionfacts.org/video/how-to-treat-periodontitis-...

https://nutritionfacts.org/video/best-food-for-periodontal-d...

https://nutritionfacts.org/video/plant-based-diets-dental-he...

Click on "sources cited" to find plenty of research

Greger's site. About what I was expecting...

This has to be weighed against anecdotal evidence ( good anecdotal evidence is IMO better than your average study/research) from vegans. Vegans tend to have very high occurrence of cavities despite the best of oral hygiene. ( source ex-vegans on their blogs etc.) Eskimos when first discovered by western explorers had a complete absence of cavities despite bad oral hygiene and a diet of almost no plants (Source: A book written by an explorer, whose name I cannot remember)

> I brush, floss, use the pipe cleaners for between teeth, and run one of those pointy rubber things along the gum line, and still get gingivitis. My dentist says there's nothing more I can do about it.

I am not a dentist but have similar issues:

Consider wearing a mouthguard at night? Grinding teeth during sleep can contribute hugely to bone loss.

Also make sure you're using the rubbertip correctly. It's supposed to massage the gum with the flat part, not poke with the pointy part.

You could try a dental probiotic. I got slightly better gum gap scores when I was using this one, though I stopped because I thought it was upsetting my stomach a bit. Probably going to try it again after that recent research on gingivitis and Alzheimer's. http://www.biogaia-prodentis.com/dental-professionals/

1. What do you think about charcoal tooth pastes? I've been using this[1] and it got rid of my persistent "plaque wall" on lower incisors within ~month. I don't feel this particular one is really abrasive, but I was wondering will there be some damage to enamel with persistent use? Should I maybe alternate it with normal fluoride paste?

2. I've heard that brushing teeth before sleeping, regardless of food consumption, is great because of reduced saliva during rest means reduced anti-bacterial effects of it. Any truth in that?

3. Last dentist appointment I got mentioned that my tooth will literally explode if I don't remove it. I've read there been odd cases of that happening in history, but is there realistic chance of that happening? How would that even come to pass?

[1] https://www.splatoralcare.uk/products/biomed-charcoal-toothp...

P.S. Thanks for doing AMA. I've had nothing but horrible experience talking with dentists, or even bad experiences in general.

The exploding tooth thing is true, caused by gases released by the decay building up pressure, can be very very painful: https://en.wikipedia.org/wiki/Barodontalgia#Barotrauma

What you're saying makes sense.

On the other hand, what are your thoughts about the relation between the type of foods we eat and dental health?

My understanding is that sugar, and (complex?) carbs in general have a massive toll on teeth. Admittedly I'm no expert, but it would seem that eating the food we evolved to eat (vegetables and meat mainly) should not damage our teeth in a significant and therefore would be no need for dental health practices.

Whether or not that is feasible on a population level is another question, but I'm fairly convinced at this point that the garbage food is wrecking our health and that includes teeth.

Actually inflammatory diets like diets high in animal protein seem to pose more of a risk to dental health than diets rich in healthy, complex carbs:

https://nutritionfacts.org/2013/07/25/do-vegans-get-more-cav...

"it's pretty obvious that removing rotting food from your gums is good and leaving it there to putrefy is bad, don't you think?"

But is that actually true? Has anyone actually confirmed it with replicable scientific studies? Did early human teeth rot to hell over the first 10 years of their lives? Why don't cats and monkeys need to brush and floss?

"please use your common sense"

The problem with common sense is that it can be deceptively nonsensical, and we tend to ignore that we haven't proven it because we "know" it's true already.

Pets, cats, and dogs only live until they're 20. AND pets DO have lots of problems with dental health. What is with all these people questioning flossing here? Floss your damn teeth. Worst that can happen is the poor guy you work with doesn't have to smell the decomposing food coming out of your mouth. JFC

We’ve changed pet food just like we’ve changed our own food. Notice how pets and animals that eat human food (like raccoons) are all getting fat together.

Looking at modern dog dental hygiene to learn about how wild animals’ teeth work is as silly as looking at our dental hygiene to see how a hunter gatherer’s teeth work.

Our vet told us to brush our dog's teeth.

Works best with meat-flavored toothpaste.

Did your vet recommend to floss your dog's teeth?

I'm a veterinarian. Some cats get lucky but the majority of them deal with tooth resorption which is caused by gingivitis. This disease is found on tigers, jaguars, fossilized saber tooth tiger teeth, etc. It's painful and leads to loss of teeth. Often also leads to loss of function, i.e., reduced chewing. It's probably a leading cause of old wild cats throwing in the towel and becoming carrion.

Yep. My cat had a mouth full of rotten teeth. After removing nearly all his teeth his entire disposition changed—went from just sitting around all day to a ball of energy. It also changed his digestion: went from runny poop everywhere to Tootsie rolls.

Hunter gatherers typically had much better teeth than modern humans, although outliers do exist. The general explanation for this is that diet and nutrition have a much larger impact than mechanical cleaning do.

Recently I had a bad cavity (back of mouth, didn't hurt until gigantic, don't go to dentist regularly) and very minor bone loss in my jaw next to it. In the process, a dental hygienist explained that the primary purpose of flossing or waterpicking is to prevent bone loss in the jaw which can lead to infection and tooth loss if left untreated.

Thanks to waterpicking, the gums in that area of the jaw have healed and I shouldn't experience any more bone loss as long as I waterpick or floss.

What's your opinion of Zirconium tooth replacements, as done by BioImplant (www.bioimplant.at)?

From my not-a-dentist :) perspective, the concept sounds workable.

eg creation of the 3D model from scans, using a CNC machine to create the object from Zirconium, etc.

But I've no idea what other parts would need evaluating to make real sense of it. :)

It's a cool idea and I'm pretty sure it will be more common in the future, but right now almost nobody uses it for a couple of reasons:

1- You actually need a CAT scan of the tooth you want to replace beforehand..sometimes it's not possible (i.e. people who lost their teeth years ago, and now want to replace them)

2- Costs are probably significantly higher for everyone

3- Normal implants are more versatile, as they are basically hollow screws where you can mount a second screw shaped however you want (a tooth abutment, an attachment, etc) so they are also used to stabilize dentures, to create full mouth reconstructions such as all-on-four etc..this is not possible with these zirconia implants

I will ask you anything then! Please tell me why I have to be sedated for everything. No amount of anesthetic ever works on me. Drilling always feels like a horrifying electric shock. And every time they touch my fillings with a metal probe, I get shocked too.

I’m not afraid of needles. I’ve had plenty of uncomfortable medical procedures. I can tolerate all other kinds of pain. But why doesn’t local anesthetic work on me for dentistry?

Do you have red hair?

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1362956/

That article is about a different process, inhalation anesthetic, rather than local (nerve-blocking,depolarizing) anesthetic.

TBH I have never had a patient on which anesthesia didn't work...the only case that's fairly common is if you have an acute infection on that tooth, in which case the effectiveness of anesthesia is greatly reduced

Lower molars receive 2-3 different innervations and it is sometimes hard for a dentist to get all of them numb

I'll say that some dentists are good at nerve blocks and others are not. Bupivacaine takes time to work and some dentists don't allow it to take its proper time. But if you have a local anesthetic properly infiltrating the nerve, and given the time to work, you will have no sensation.

You could have a sodium channel mutation (such as SCN9A) that makes you highly pain tolerant, but lidocaine-resistant[0].

It's a known syndrome, and may be associated with ADHD symptoms, episodes of intense skin flushing or redness (erythromelalgia) and epilepsy.

0. https://www.healthbusinessgroup.com/2008/01/11/what-causes-a...

Other medical sources:

  https://www.ncbi.nlm.nih.gov/books/NBK1163/
  https://www.ncbi.nlm.nih.gov/books/NBK481553/

Thank you so much. yes on the ADAH, no the skin flushing. Really appreciate your help.

> a powered toothbrush is better simply because it does more iterations per minute than a manual one...again, common sense

It wasn't obvious to me that that would be true. Most cleaning tools aren't vibrating brushes.

I was actually concerned about damaging the teeth. You are effectively putting a power tool in your mouth.

Doesn't empirically demonstrating the efficacy of flossing face all the same challenges as any other medical research?

Of course it is difficult to definitely prove whether or not vitamin C supplements reduce the duration of a cold. That doesn't mean that we should all just abandon empiricism and start gulping vitamins because it is "common sense."

What if someone's "common sense" leads them to believe that use of a an abrasive cleaning technique like flossing might damage their gums? I can think of any number of non-scientifically backed rationalizations one could use for or against flossing.

So, even if not-definitive, what research is there on whether flossing improves oral or overall health?

What I meant with that "common sense" sentence was basically this:

- It's irrelevant to know if flossing "improves" overall health...what is relevant is that it will not worsen it, and you are removing rotting stuff from your teeth, and worst case scenario you just waste 2-3 minutes and have a more pleasant breath..why overcomplicate things?

It doesn't worsen your health, it either does nothing or improve it, so it is reasonable to do it

Medical literature is full of these things: do you need people to prove it with several studies that it's good for you to go for a walk every day? Try to weight the cost-benefit of your actions...if the cost is small, the risk non-existant, and the potential benefit high, it's usually a good idea

> It doesn't worsen your health, it either does nothing or improve it, so it is reasonable to do it

There are thousands of wives tales and pseudoscience remedies I don't need to waste my time on. If not backed by actual science, this type of recommendation is no better than any of them.

Here's the latest info I found on PubMed: https://www.ncbi.nlm.nih.gov/pubmed/30968949 - "Home use of interdental cleaning devices, in addition to toothbrushing, for preventing and controlling periodontal diseases and dental caries." As dental plaque is the primary cause [of tooth decay and gum disease], self-administered daily mechanical disruption and removal of plaque is important for oral health. Toothbrushing can remove supragingival plaque on the facial and lingual/palatal surfaces, but special devices (such as floss, brushes, sticks, and irrigators) are often recommended to reach into the interdental area... Using floss or interdental brushes in addition to toothbrushing may reduce gingivitis or plaque, or both, more than toothbrushing alone. Interdental brushes may be more effective than floss. Available evidence for tooth cleaning sticks and oral irrigators is limited and inconsistent. Outcomes were mostly measured in the short term and participants in most studies had a low level of baseline gingival inflammation. Overall, the evidence was low to very low-certainty, and the effect sizes observed may not be clinically important. Future trials should report participant periodontal status according to the new periodontal diseases classification, and last long enough to measure interproximal caries and periodontitis.

Basically, good current dental hygiene practice is to brush and floss like the experts tell you.

Interesting. I wonder why there aren't better studies on this, particularly when flossing is so widely recommended.

Does eating green vegetables, salad, herbs (I love chewing some wild thyme in the countryside) help significantly the teeth health?

Also I don't rinse after brushing my teeth, to keep the toothpaste in place so it acts as protection all the night, is it useful too?

Cavities are caused by sugars (and sugars only), so in theory, if you just eat green vegetables and meat, you shouldn't get any cavities. Veggies contain fibers and the consensus is that they exert a light brushing action on teeth (think when you chew celery and such)

A great resource for these questions is nutritionfacts.org (free and full of references to scientific studies)

As for toothpaste, what you do is ok, the only risk you run is to overdose on systemic fluoride, which sometimes causes diarrhoea. An alternative is to rinse with a mouthwash and not rinsing with water afterwards

Are there any long term health risks due to the material used in dental fillings? Any changes over the last 10-20 years? I’m thinking cancer associations, etc.

Is the science on xylitol still up in the air? Is it likely that it's at least as harmless (compared to sugar) as other sugar alcohols (erythritol, sorbitol, etc)?

My dentist gave me two options for removing my wisdom teeth a few years ago, 1: go to a dental surgeon and be put under, 2: have some kind of anesthesia but not be "asleep". I chose #2. It was some sort of concoction that, if I remember correctly, was only meant to stop me from remembering the pain/experience.

I don't have the paperwork but I've always been curious what is was that he gave me/if it was common practice. Also, if it was purely a sort of amnesia, was I in excruciating pain during the time?

I have since moved away and not been back to a dentist. If it is common, I can only imagine the stupid things I would have said or done during the procedure since during the onset I remember being extremely high. It kind of made me embarrassed to return the couple of times I did only because I don't remember what I could have done.

Good dental hygiene does what it's supposed to, but the biggest factor is basically luck - you either "have good teeth" or you don't.

There's evidence that your mom's prenatal diet (and not strictly genetics) may be a salient factor.

https://www.amazon.com/Nutrition-Physical-Degeneration-Westo...

This book is eye-opening. A dentist traveled the world in the early 20th century when there were a lot more indigenous people to visit who had had no previous contact with modern processed flours etc. Those still on their traditional diets almost all had excellent teeth, without ever owning a toothbrush. But when modern foods were introduced, their teeth went to shit within a generation. Probably some epigenetics playing a role, though they didn't know about that then. Also I believe this may have been before flours started being fortified, so you would probably see a less pronounced decline if you somehow did this today. But the takeaway seems to be that a high protein paleo-ish diet kind of takes care of everything.

I don't know. Chalking things to luck seems... like an admission that we don't actually understand the causal factors that well. Especially combined with your other evidence that there was a clear delineation between folks with good/bad teeth.

Actually, your point about flour heavy diets basically sending folks that used to have perfect teeth to cavities sounds very not luck based. Which is it? Genetically some folks have cavities, or that common modern diets lead to cavities?

The luck aspect, under this particular hypothesis, would be that either your mom ate well or she didn't.

But it literally goes against the other argument. That isn't luck, that is prior choices having a larger impact than current choices.

If diet of the mother is important, we can start educating future mothers to have diets that help. Sure, there is no panacea for people with bad teeth today, but that is true for a lot of things we take corrective action on.

Getting into the existential weeds a bit here with free will and all, but that's OK with me. I'm not using a strict definition of purely random luck here. I'm using a looser colloquial definition under which choices by yourself or others can affect your luck. Like if the dictator chooses to chop off all heads with my hair color today, that's bad luck for me, even though he caused it. Or if I choose to drive drunk, and hit a utility pole, that's bad luck for me, even though I caused it!

Here's a trans-generational example: My dad makes a bunch of awesome choices that result in his becoming rich. Then I get born, and someday inherit that fortune. I'm much more inclined to describe my own outcome as luck than his, probably because my own decisions had less to do with it.

On the other hand it's not really so straightforward, because so many occurrences are attributable partly to random chance and partly to free will by somebody or somebodies. Maybe my rich dad benefited from luck, like not being crippled by polio or war, or not being born into a repressed social group. And of course my own "good luck" is a result of dad's explicit choices (your point), plus it also hinges on my own actions, such as not doing anything particularly atrocious to alienate him such that I get written out of the will. So is he a genius or just lucky? Probably a bit of both. Am I lucky or just shrewd/a good son? Probably a bit of both.

Ok, I was following "luck" as in "non-deterministic."

Pulling it back to what I think you are saying, though; there are still some obvious points that need more exploration for a causal factor. And if it can be found, then it should be exploited more.

So, if there really is a link between mother's diet and bone health, we should find out what that link is. If it is diet related, we should find out what about the diet leads to it.

I'll note my bias. I have the best teeth of my siblings. I likely have the worst brushing habits. Even in grade school, when I had braces, I would brush the night before the dentist, and would generally chew gum/whatever whenever I wanted. Easy to say I got lucky genetically. But what if there is more to it than that? What if my genetic luck was my allergy to damned near all food which knocked out some specific food that caused issues? (Would be almost poetically ironic if it was milk or some such.)

So, colloquially, I don't disagree that luck is a big factor. I just don't think luck should rule out looking for causal factors that can be exploited. Pretty sure that is standard for exploration/exploitation strategies in any learning scenario, no?

Yep it is, and we should most definitely nail it down with further study. Especially since, as you kind of hinted, it's so hard to isolate or control all the variables when you're dealing with people just living their lives.

It doesn’t need to be the food, it could also simply be the case that they never got exposed to caries-causing bacteria.

As a 20-something I often skipped brushing, never flossed and would rather have a leg amputation without anesthetic than visit a dentist.

In my thirties, I experienced a lot of dental problems such as toothache, bad breath and gum disease. Eventually it got the point where I was in so much daily pain that visiting a dentist didn't seem such a bad idea after all.

For the past 18 years or so I've followed a strict regime of brushing twice daily, flossing and three-monthly sessions with my hygienist.

My hygienist is fastidious and is always disappointed in me, no matter how hard I try she'll always find a spot I'm missing or not cleaning thoroughly enough.

Regardless of this though, my dentist checks me over every 12 months, I have x-rays every 18 - 24 months and there are seldom any problems.

I've had a couple of treatments for chipped enamel over the past 18 years but, apparently, that's a result of aging rather than poor hygiene. Nothing else.

So, yeah, the scientific evidence for regular brushing my be lacking but I'll take my personal experience any day of the week thanks.

I’m in a similar boat, but my teeth are pretty good. The one thing to look out for is bone loss caused by inflammation, which is why flossing is so important. Bone loss won’t cause your teeth to fall out until you are 60+, so it’s easy to ignore even if it shouldn’t.

That was never explained to me as a kid, so I never learned how to floss right or why it was important. I guess I can do a better job as a parent with that wisdom, at least.

My parents made me floss, but I hated it, so when I went to college I quit. Then I had a dentist make me promise to take it up again for just two weeks, which I did. At the end I thought, "Finally, I can quit this stupid annoying waste of time once and for all." I stopped for one night and the next morning I woke up with the most disgusting taste in my mouth I had ever experienced. I haven't missed a day of flossing since then, and it has been 30+ years.

Life hack: use POH brand dental floss, the white stuff, not the black. It's much thinner than the competition and so it's much easier to use.

As a 20-something, I moved away from home and neglected to find a new dentist. I kept putting it off, but to make myself feel better, I brushed more aggressively and more often (after every meal and snack). After 8-10 years of this, I didn't have any cavities, however I had the start of gum erosion. This grew worse, and I eventually had to have a gum graft. That's a procedure that I would not recommend to anybody.

Did your dentist or doctor posit a reason why your gums started eroding? Is it hereditary? What else could you have done to prevent the erosion?

Aggressive/harsh brushing is generally what is identified as causing gum recession, and that matches their story.

Brushing too much and too hard, and to a certain extent, not flossing.

I now brush gently and floss daily. I never want another of those grafts.

I wonder if one can readily track toothbrush [handle] and jaw movements tightly enough to produce a "brushing map" indicating areas that are getting less attention.

Or perhaps a special brush with accelerometers (or other sensors? cameras in the head?) would be needed?

> I wonder if one can readily track toothbrush [handle] and jaw movements tightly enough to produce a "brushing map" indicating areas that are getting less attention.

They invented this decades ago.

I remember in the 80s when I was a kid going to the dentist.

They would get you to chew some type of pill that temporarily stained your teeth. Then you would brush your teeth while your dentist watched.

In the end you were able to see exactly what you missed because of the stain. It was really a genius product.

Back then it was something you did at the dentist's office but it looks like Amazon has them for sale at: https://www.amazon.com/Butler-Red-cote-Dental-Disclosing-Tab...

I'm not a dentist, so I would ask your dentist before trying them.

Like programming, being able to see the output of what's happening really helps debugging!

The problem is, and I used disclosing tabs as a kid too, that unless you're being continuously monitored your behaviour can alter. I think the concept I raised is different.

Seeing inputs is also useful.

I guess if you were to use disclosing tablets every time you brush ...

It's like typing. After you do it enough times you don't really need to look because it's locked in as muscle memory.

So in this case, you'd probably want to use 1 tablet a day for maybe 10 days in a row or keep using the tablets until you can consistently see you're getting good coverage. Then after you've done it a few days in a row with good coverage you know what it feels like and you're good to go.

The package comes with over 200 tablets so you'll have plenty of practice opportunities.

> I wonder if one can readily track toothbrush [handle] and jaw movements tightly enough to produce a "brushing map" indicating areas that are getting less attention.

Oral-B's Bluetooth toothbrushes with the Oral-B app shows a mouth map and tells you where you're missing. Available at almost all major retailers.

PS - I don't realistically think people will use Oral-B's solution daily, too awkward (requires sticking the phone to a mirror/face alignment), but useful for "spot checks."

Personal experience isn't science. What about those people who brush their teeth, floss, etc and still have teeth problems? Do their personal experiences matter?

Also, in addition to brushing and flossing, did you change your lifestyle? Did you start eating better, working out or changing your diet? Were you stressed when you were younger but have less stress now?

You can't even rule out the placebo effect. Does going to a hygienist make you think your teeth/gums are healthy and therefore boosts your immune system and the health of your gums/teeth?

If something works for you, that's great, but that isn't science.

'You can't even rule out the placebo effect. Does going to a hygienist make you think your teeth/gums are healthy and therefore boosts your immune system and the health of your gums/teeth?'

I can't wait to discuss this theory with her.

Also, regarding the guy that doesn't trust dentists that posted below...consider this - You had a very good dentist for several years that never suggested you do unnecessary procedures

This dentist had the balls to drop out of network, probably because he's good and has enough patients to not cave in to the absurd demands of insurance companies (they pay far less than a FFS practice, just FYI)

So you decide to drop your good dentist, and go to lower quality ones, just because they are in-network (guess what? these guys actually need to drop their fees because they don't have enough patients otherwise)...and then you find out that these new dentists are lower quality and need to prescribe unnecessary procedures to make ends meet

Solution: like in any other field, value quality over price, go back to your old dentist.

It's like Apple charging more for an iPhone simply because it's higher quality and is time-tested, of course if you buy cheap cell phones they are worse and screw you up some other way.

The real problem is insurance companies here, they are screwing both dentists and patients extracting money in a place where they shouldn't be (why do you need a middleman between a doctor and a patient anyways?)

> why do you need a middleman between a doctor and a patient anyways?

I agree, we don't.

Problem is right now if I pay for dentistry via "insurance" then it is pre-tax dollars and or my employer pays some/all of the premium. If I pay it completely out of pocket, I am now using post-tax dollars and my employer isn't picking up a percentage.

Our incentives themselves are irrational. You're essentially forced to go through insurance/your employer, and punished if you don't.

I'd love to see both dental + health insurance "unbundled" from employment, and a large HSA-like pre-tax savings account which can be used on premiums, that employers can choose to contribute to (in cash dollars). That way if you wanted to skip dental insurance, and pay per-treatment you could (and pick any health insurance plan you liked, including ones that could include dental benefits).

PS - The reason the existing HSA structure doesn't work for well for dental is two fold: It requires high-deductible health insurance, and the cap is low when you start using it for other areas (vision/dental).

I think we can all agree insurance is something of a racket, but are you implying in-network dentists struggle financially? I would find that difficult to believe considering the limited hours many dentist office's hold in the midwest coupled with the month+ wait time for an appt.

I tried to find studies for the effects of teeth brushing frequency but the only ones I could find were cohort analyses as opposed to randomised trials. It seems like despite a lack of evidence, it would be very hard to ethically approve a randomised trial of teeth brushing over a long period. I honestly believe brushing teeth twice a day is very much a ritual which achieves very little on a per effort basis.

Reducing our intake of sugary and acidic foods and drinks would have a much greater effect with much less effort. The problem is that the profit margins on carbonated flavored water are massive so the opposition to such change will be huge.

> It seems like despite a lack of evidence, it would be very hard to ethically approve a randomised trial of teeth brushing over a long period.

This is the exact same argument that was used to evade studying the effects of low doses of aspirin on heart disease. Everyone “knew” it worked, so it was thought to be unethical to put people at risk of heart disease into a control group. Many millions of people spent money for years to consume a constant supply of aspirin.

When the question was finally studied, it all turned out to be nonsense. In fact, it turned out to increase death rates from higher cancer risk. All that money could have been spent on actually improving health.

https://utswmed.org/medblog/aspirin-heart-disease/

> When the question was finally studied, it all turned out to be nonsense.

That's certainly not the conclusion I came to at all from the article you linked. The main takeaway I got was that daily aspirin may not be warranted if you're not at high risk of heart disease (one reason earlier studies showed more conclusive benefits of aspirin is there were more smokers, i.e. more high risk people, back then).

So yes, it makes sense to look at risk/benefits for individual patients rather than "all old people get aspirin", but the idea that aspirin can protect against heart attacks is not nonsense.

I am pretty sure that low dose aspirin has some benefits for some people/conditions. At least I remember reading studies that suggest as much.

So naturally I was curious about it being “nonsense” for heart disease.

A quick skim of the article + a quick search shows it’s not as clear cut and conclusive as you suggest.

Interestingly, neither is the increased risk of cancer discussed in the article. Aspirin has been shown to have the opposite effect too.

I found it hard to glean what dosages where used in the studies mentioned in the article but the couple I saw were 100mgs per day. I didn’t see mention of if they were enteric coated or taken with meals.

In the US baby aspirin is 81mg and in the UK there are 75mg available. Both are enteric coated. In Australia it seems 100mg might be considered low dose and widely available.

It would be interesting to see more studies on this topic using lower dose, coated, aspirin taken with a meal. The US/UK low dose aspirin are 19-25% lower than at least a couple of dosages the studies mentioned. Those lower dosages may help mitigate bleeding risk.

Seeing as some of aspirins effects are longer lasting, perhaps alternative dosing schedules could also be looked at (every other day etc.) - this may further help mitigate the bleeding risk whilst still providing benefit.

The doses were different for legal reasons. Aspirin for children is unnecessarily risky in most cases but different countries set different cutoffs for restricted doses vs. unrestricted adult doses.

But ya, dosing is underrated. Something that's bad at X dose may be beneficial at 1/Yth the dose.

anecdotal but i’ve visited third world countries where they don’t brush at all and some people had great teeth (others... nkt so much). not sure if it’s genetics or lack of sugary and acidic foods

They didn't brush their teeth, but were they chewing on small pieces of wood, or usong other traditional method of dental hygiene?

afaik they didnt do anything

Were you evaluating only color and straightness or were you looking for caries and periodontitis?

the first

I agree. I’ve struggled with my teeth for years. Always hearing twice a day. But what I’ve learned is it does no good to wake up and brush your teeth and then have a coffee with sugar that sits on your teeth for several hours. I think one may need to brush many times a day depending on what you’re eating habits are. But I’ve also heard too much brushing can hurt as well so I still do a main brush morning and night but if I have something sugary or acidic I do a real quick brush. I truly believe for the best results you need to consider your teeth for the entire day and rinse them accordingly.

Hmm, you need to be careful -- AIUI if you have acidic foods then they soften the enamel, brushing immediately after can thus damage this enamel.

How is carbonated water bad for your teeth?

Carbonated water is very mildly acidic.

Sodas (the sweetened ones), which I’m guessing are what GP is mostly referring to (what with the mention of sugar earlier in the paragraph) have sugar, which may encourage the growth of bacteria that are detrimental to teeth; and some of the flavorings are more acidic or react chemically with enamel to dissolve it.

The carbonation is one thing, but your saliva has lots of buffers to maintain pH.

There's usually a pile of acid added for "tartness" to sodas that lower pH, which overwhelms the buffers.

Often, it's phosphoric acid. Phosphoric acid will quickly react with any free calcium to form insoluble calcium phosphate which will mostly go right through you. So not only are you robbing your mouth of calcium you're also robbing the re-supply process.

Phosphoric acid is the bigger risk

> it would be very hard to ethically approve a randomised trial of teeth brushing over a long period.

The ethics aren't too difficult because we don't have strong evidence one way or the other. I think a bigger issue would be blinding the study participants. The groups assigned to the higher frequency brushing may change other routines (e.g. diet).

> The problem is that the profit margins on carbonated flavored water

It could also be the strong acidity of a lot of drinks in general, even if we replace the carbonation/sugar with something else.

Importantly, phosphoric acid is the worst, carbonic acid is not as strong. I'm recently switching from sugared colas with phosphoric acid to naturally flavored carbonated water

A similar article in The Atlantic was submitted a few days ago:

https://www.theatlantic.com/magazine/archive/2019/05/the-tro...

There's even less evidence for pulling wisdom teeth:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1963310/

("The Prophylactic Extraction of Third Molars: A Public Health Hazard")

I'm lucky like the author. 47. Zero cavities. Gums are healthy. Brushed infrequently as a kid and never flossed. Teeth were treated with fluoride by a dentist as a kid. Didn't start brushing daily till high school. Didn't start flossing daily till my thirties. Skipped going to the dentist at all for maybe 5 years in my mid-twenties. Typical western diet. Never had braces. Straight teeth.

Both parents, both sisters, and my brother all have several to many fillings.

No smokers.

I see my dentist twice a year but they only take x-rays every 18 months.

I'll add one. I had bad cavities and several root canals by the time I was 22. Dentist told me to start using a fluoride mouthwash. I use it occasionally (few times a week?), no new cavities for 10 years straight. Seriously no other change.

No change in diet at all?

Nope, if anything it's worse.

> Never had braces. Straight teeth.

= win, probably the main reason for everything else.

Perhaps you just got the right mix of soft and hard food in early childhood and developed a perfect jaw. Or good genes and different father. ;-)

> There's even less evidence for pulling wisdom teeth

At 21 my dentist wanted to pull my wisdom teeth. I asked why, he said they're hard to clean and I'd lose them at 30 anyway. I said I'd take my chances and found another dentist.

I'm old now, still have them, and they're still in good shape.

That there are no randomized control studies is hardly surprising: nobody would ethically assign a person into the "no dental care" control group.

I am reminded of the randomized control study they did on parachutes which showed that parachutes were useless. Of course, to ethically allow people to jump out of an airplane without a parachute, they made sure the jump was not more than a meter and a half off the ground.

What that satirical study actually showed is that randomized control studies don't always make sense.

The study page: https://www.bmj.com/content/363/bmj.k5094

The study PDF: https://www.bmj.com/content/bmj/363/bmj.k5094.full.pdf

>That there are no randomized control studies is hardly surprising: nobody would ethically assign a person into the "no dental care" control group.

They're not saying "no dental care". They are saying "no dental floss", or "no fluoride toothpaste", or "no fluoride in water", or "brush once a day". The reality is that a significant percentage of the population falls into one of these three categories (I was surprised you could by toothpaste without fluoride, but you can - there's a market for it).

And yes, while you can't do true randomization, you can compare dental outcomes between these groups.

And finally, saying it's "unethical" is a stretch. It's not unethical if there is no good reason to believe these measures are good for health. Until there's a clear study, these all fall into the same category as other traditional/folk medicine. When I first went to my current dentist years ago, he said "Your insurance covers two cleanings a year, and we'll give that to you. However, I'll have you know that there's no evidence that twice a year is better than once" and he proceeded to tell me a bunch of other common dental practices, their origins, and the lack of studies on them.

It reminds me of the whole 8 glasses of water a day belief, which until about 10 years ago was commonly promoted by doctors. Then in about 2005-2007, someone published a literature survey showing no studies had ever recommended 8 glasses with good reason. All my doctor friends knew of this survey and promptly stopped recommending it.

I agree with everything you are saying. Let me rephrase what I was saying so you can see we more or less agree.

The article is complaining that there are no randomized control studies and using this to conclude that there is little evidence to support flossing. They are simply disregarding other types of studies like the observational study you are pointing out have value. These observational studies show such clear benefits to flossing that directing a person to stop would be considered unethical. I am pointing to a more facile example where you would never imagine performing a randomized control study because it is obvious that the no treatment control is dangerously unethical.

Doctors end up being susceptible to public misconceptions just as much as the general public. Not everybody reads original research or health guidelines. So someone hears that the official guide recommends 2.5 liters of water, with no mention of the accompanying note that most of this comes through ordinary food intake, and they misinterpret it as needing 8 glasses of water a day. That is the case for the 8 glass a day myth: no scientific study ever recommended it, but half readings of some literature seemed to imply it.

If you like myths like those, read through https://www.snopes.com/fact-check/water-works-2/ especially when it gets to the diuretic effects of caffeinated beverages. I mostly learned about this when I started talking to foreigners about it and realized it just wasn't common knowledge outside of North America that caffeine causes dehydration.

I think individual dentists will often go on anecdotal evidence. A single dentist may fix 10k+ teeth or more and treat the same patients over 20 years or more and is therefore often well placed to consider what worked in their practice.

This is often exactly what you want actually ... controlled trials typically can’t take into account enough useful variation in patient conditions to be a useful guide for any given patient. Meanwhile the dentists mental database can be ... if your dentist is a good one.

Anecdotal evidence is widely considered inferior to controlled studies, and for good reasons: Confirmation bias, survivorship bias, etc. are incredibly hard to avoid for a single person even if they're aware of them.

it just occured to me that natural selection is basically survivorship bias. hahah

Anecdotal evidence doesn’t have to have any of those qualities but I do think that’s exactly right, yet most decisions just won’t have a basis in controlled trials due to the variation in the patient group and because you just can’t have controlled trials for most things .

For example, implant placement at a 45 degree angle are totally weird mechanically speaking given that the biting force runs down but dentists may do them to recruit better quality bone because they know that implanting into low density bone or calcious mass will likely lead to an implant failing but they just don’t see much failure due to weird angles ... this particular case happens so often actually that some companies now recommend placement at 45 degrees.

Personally experience, conferences, etc . It’s not how the world ought to work but it is how it mostly does.

Surely the twice-a-year teeth cleanings matter? In 2005, Evidence-Based Dentistry highlighted a systematic review on the effects of routine scaling and polishing (you call it teeth cleaning).

It very obviously works aesthetically, especially if you drink a lot of tea. I had no idea it was even supposed to have any health benefits besides the free check-up which some (my) dentists throw in.

This recent article on the Atlantic is more interesting read: https://www.theatlantic.com/magazine/archive/2019/05/the-tro...

Covers both lack of evidence-based science in dentistry, and also culture (thankfully doesn’t seem to be the norm) of over treatment.

For some history of teeth (not just human teeth) try the BBC In Our Time podcast episode The Evolution of Teeth:

https://www.bbc.co.uk/programmes/m0003zbg

Being a Melvyn Bragg podcast, it includes a reading list:

Barry K. B. Berkovitz, Nothing But the Tooth: A Dental Odyssey (Elsevier, 2016)

John A. Long, The Rise of Fishes. 500 Million Years of Evolution (The Johns Hopkins University Press, 1996)

Neil Shubin, Your Inner Fish: A Journey Into the 3.5-Billion-Year History of the Human Body (Vintage, 2009)

T. M. Smith, The Tales Teeth Tell: Development, Evolution, and Behaviour (MIT Press, 2018)

Peter S. Ungar, Teeth: A Very Short Introduction (Oxford University Press, 2014)

Peter S. Ungar, Evolution’s Bite: A Story of Teeth, Diet and Human Origins (Princeton University Press, 2018)

The main differences in outcome, like the anecdote the article leads with, might be due to different micro-flora in the mouth.

I used to get plaque build up something awful, but since I started taking probiotics a few years ago for another problem, I don't seem to have that problem anymore.

There's also evidence that brushing with toothpaste ("dentifrice" in scientific papers) does not remove plaque any more effectively than brushing with plain water:

https://www.ncbi.nlm.nih.gov/pubmed/27513809

Toothpaste can also deliver fluoride, but I drink a lot of tea (which concentrates fluoride from the soil) so I'm more concerned about excessive fluoride exposure than too little. I've been brushing my teeth with plain water for years and they are as healthy as ever.

You can use toothpaste with some of the other enamel supporting materials popular overseas, like nano-hydroxyapatite.

Sample size of 1, but I've done several A/B tests to see what works better for me.

Works:

Xylitol. Been trying this recently, and it is amazing. Using the Xlear sinus mist has massively reduced snoring and sleep apnea issues. Using Xylitol as a mouth wash - my teeth feel much smoother now. Go do the research and check it out for yourself.

Apagard toothpaste. Its pricey, but switching to this dramatically reduced the drama during dental visits.

> Its pricey, but switching to this dramatically reduced the drama during dental visits

What drama was there during dental visits? Found cavities? How often do you go to dentist/how often did the drama happen before you switched toothpaste? Sorry for blunt questions, I really don't know what that could mean.

No cavities since I found this toothpaste. Also, greatly reduced tooth sensitivity. I go to the dentist every 6 months.

I had dental insurance a couple years back and went to the dentist for a cleaning after probably 10 years and the dentist and the cleaning tech both said my teeth looked about like I skipped my last 6month visit (before I told them it had been a decade)

Now that I’m not spreading the cost out over the year it is harder for me to get motivated to go and pay $250.

Surprised to see nothing about carbohydrates in the article, nor here. I have been following a diet very low in carbs recently, and one thing that surprised me is that my teeth never hurt anymore. It wasn't the reason for my diet, but it's a really nice benefit.

I noticed a causal relationship between eating eating sugary foods and toothaches, so I cut out sugar a few years ago, which reduced the pain by 80%. But there was still a subtle aching after every meal, sometimes even if I immediately brushed my teeth (can't reach every single place).

But cutting carbs altogether, has completely eliminated the mild background toothaches (and not so mild ones) I just took for granted.

I heard recently that with the advent of agriculture, humans switching to a carb-rich diet, cavities (in found skulls) increased by 500%.

I've read similar articles before, and yet I still feel the need to follow all the suggestions.

I floss daily and brush a little more than 2 minutes each time. Still get dental issues, but I feel like it would be worse without it.

Maybe just doing something makes it feel like I have some control in the process.

I've found through personal experience that diet and general health are most important for teeth. I used to get a cavity a year. Once I cut sugar out 100%, reduced carbs, and started eating healthy, I've had no cavities for 10 years. I don't even use a fluoride toothpaste, and sometimes forget to brush. The dentist always compliments me on my teeth.

I met some dentists the other day that waterpicks may be doing more harm to gum density, while still helping get food particles out to avoid plaque building (which itself will do harm to gum density and cause other forms of decay)

yeah well its not like my non-existent flossing habits will supplant my waterpick half-solution. But I do wonder the support for any of this wisdom.

When I first discovered Waterpiks a year ago, I was extremely frustrated at the fact that all dentists hate it, and that there were very few studies on it. The universal belief, found all over the Internet, is that Waterpik is good for removing food particles, but is ineffective at removing the film, which regular floss does.

This really should not be hard to validate.

The only study I could find showing this was done in the late 70's. Waterpiks have changed a lot since then. And you'll find plenty of studies showing how effective Waterpiks are at removing that film. All these papers were funded by Waterpik.

Why are dentists insisting Waterpiks are bad when there is no independent study comparing modern Waterpiks with regular floss? And why doesn't anyone do the damn study?

My dentist and his team of hygienists are big fans of waterpiks, but not as a substitution to anything. You would still brush and floss (with string) as usual.

A waterpik used incorrectly may cause gum problems, so maybe that's why dentists don't like them across the board. If you put the thing on the highest setting and aim it so it pushes your gums up that may cause damage.

But if you keep it at a low / medium setting (a lot of waterpiks go from 1 to 10 in terms of pressure) and aim the water straight at your teeth and trace your gums then you should be good (there's videos showing how to do it). Not only does it remove all sorts of food particles, but it also stimulates your gums.

>My dentist and his team of hygienists are big fans of waterpiks, but not as a substitution to anything. You would still brush and floss (with string) as usual.

Same as mine. Well, sort of. They never recommend Waterpiks, but they all say "Cool! You use a Waterpik! I hope you're still flossing with string, though".

>A waterpik used incorrectly may cause gum problem

Evidence?

Also, are there incorrect ways of using string floss that can cause dental problems?

>If you put the thing on the highest setting and aim it so it pushes your gums up that may cause damage.

"May" is not good enough. What is the evidence? There are plenty of people who use it at the full setting. It's not hard to study the topic. Of course, Waterpik muddles the issue because the highest setting differs from product to product - but when they publish their papers they specify a precise pressure, which is easy to measure. The other reason I ask: Their papers showing that Waterpiks are as good at removing film than string floss use fairly high settings.

>But if you keep it at a low / medium setting (a lot of waterpiks go from 1 to 10 at 0.5 intervals in terms of pressure) and aim the water straight at your teeth and trace your gums then you should be good (there's videos showing how to do it). Not only does it remove all sorts of food particles, but it also stimulates your gums.

If I do this, can you explain why I still need to use string floss? Do you have any studies showing that string floss is more effective than Waterpik when a Waterpik is used properly?

I appreciate your willing to share the information you have heard/read, and please don't take this as an attack on you, but your comment is a classic example of what I'm complaining about. Lots of claims, but not pointing to a concrete study.

> Evidence?

None, other than asking my hygienist which setting I should personally use, and she told me don't go above 5. I trust her judgment so I left it at that.

Also one of the waterpik tips (mine came with like 6 different tips) literally has a warning label that says "CAUTITION: Only use this tip on the lowest setting". It's a much sharper tip and for fun I put the waterpik on 10 with that tip and aimed it at my sink. The stream looked so powerful I'm surprised it didn't cut the Earth in half. I can't say for sure what would happen if I aimed that at my gums but I'm not trying.

> Also, are there incorrect ways of using string floss that can cause dental problems?

Yes absolutely. If you jam the floss into your gums as hard as you can sure I'm sure you'll be able to do damage.

> "May" is not good enough. What is the evidence? There are plenty of people who use it at the full setting.

I think it's because everyone is different. I know people who are 70+ and brush their teeth once a day, never floss, haven't visited a dentist in 20+ years and have little to no cavities and very little plaque build up. That's with smoking too.

> If I do this, can you explain why I still need to use string floss?

From personal experience the waterpik I have on setting 5 with the standard tip has a much different feel to it than string floss. String floss feels like it cleans the side edges of my teeth better where as the waterpik seems better for dislodging things that I have trouble getting out even with string floss.

> Do you have any studies showing that string floss is more effective than Waterpik when a Waterpik is used properly?

No, I'm not a medical doctor or dentist. I'm just a dude who brushes their teeth.

>> Do you have any studies showing that string floss is more effective than Waterpik when a Waterpik is used properly?

>No, I'm not a medical doctor or dentist. I'm just a dude who brushes their teeth.

I hope you realize that the whole discussion, and submission, is about the lack of scientific evidence to back these claims. Everyone is welcome to do whatever makes them feel better, but medical professionals should not give guidance that is not based on much evidence. Unfortunately, the dentists do not appear to have any more information than you do. Some have literally told me "Oh, we were just taught that in dental school" (regarding Waterpiks).

I just go by the results I see with my own eyes.

I see food particles that come out of my mouth after using a waterpik (even after string flossing and brushing). Normally I waterpik first but during the testing phase I did it last because I was skeptical on what it would actually do for me.

None of the staff at the place I goto say they learned it in dental school or hinted at doing it for the sake of doing it. They've been in practice for 20+ years and have seen a lot of patients. I'm guessing they have a large enough sample size to come up with something. In my opinion experience is often a good deciding factor when you have nothing else to work with.

When I switched to a low/no carb diet my gums were much less inflamed and stopped experiencing bleeding in my gums (w/ regular flossing). I also stopped getting that "filmy" feeling in my mouth when I'd occasionally sleep/take a nap before brushing after a carb-heavy meal.

It's mostly genetic. George Washington took fastidious care of his teeth yet they still all fell out anyway

How come no one has mentioned that image?

That QUIVERING image?

That SWAYING image?

That WOBBLING image?

I cannot accept we now live in a world where such things go without saying.

These quirky, looping 3d renders have become fashionable in the illustration world.

"To recap, there’s good evidence that brushing twice a day with fluoride toothpaste is a good idea, especially with a powered toothbrush. For children, there’s good evidence that the use of fluoride varnish or sealants can be a powerful tool to prevent cavities. The rest? It’s debatable."

I have read that one of the reasons for the lack of evidence is that it is really hard to run randomized the trials for these things. Getting a cohort to brush or floss exactly according to instructions fof a long period of time can be challenging.

I have never seen so many ads for tooth-related things on a single web page.

Dentist here, 35yo, ask me anything.

Why the huge variation in interventions for the same inputs?

If the same software was giving different outputs for the same inputs in 2 different locations, everyone here would see that as a concern to be addressed.

A software analogy would be: if a client asks for a simple website with a shopping cart and a newsletter, and you ask 10 programmers, you're almost guaranteed to get 10 different platforms (different CMS, different language like PHP vs Ruby vs .net)

It's kind of the same thing with dentists: a good surgeon will tend to lean towards surgery, and there are usually at least 2-3 different ways of solving a particular problem

And is there evidence/theory for "whitening" procedures as preventative care?

Peroxides are potent sterilizers and getting them deeper into teeth may clean deeper than any surface treatments, right?

They prevent you from having yellow teeth.

... I'd say they're reversal agents. They make the yellow part not yellow anymore.

At least with flossing, regardless of whether there are double-blinded controlled studies for it, it makes my mouth feel much cleaner when I do it, I can see a lot of plaque coming out when I floss, and there certainly doesn't seem to be any evidence against it.

With twice yearly dental X-rays, though, even though the doses are really small, all X-rays carry a risk of cancer, so it seems close to malpractice to request these X-rays without evidence to back it up. Try refusing X-rays at your dentist's office because you've done your own research, though, and they look at you with the "Oh I bet you don't vaccinate your kids either" look.

[Please check my numbers.]

The Banana Equivalent Dose (BED) of a mouth xray is apparently 15 for 2 xrays.

Personally I hate bananas (well, just the smell, taste, look, and texture).

Aeroplane flights (4 hrs of flying is about 2 xrays) might be a greater exposure source for people who travel a lot.

Banana equivalent doses assume that the radiation is distributed over the body. This is true for backscatter and other nonspecific radiation. It is not true for collimated radiation such as an x-ray. One explanation for "cell phone cancer" is that people who have annual dental radiographs have develop neuromas which are then (probably incorrectly) blamed on cell phones.

https://www.ncbi.nlm.nih.gov/pubmed/23211211

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