The moral measure of bad teeth

By Razib Khan | September 29, 2012 9:57 pm

Recently I was at the dentist and I was told that because I did not have any caries at this age, I would probably not have to worry about that in the future (in contrast, I do have some issues with gingivitis). I wasn’t surprised that I didn’t have caries, I have no great love of sweet confections. I had chalked up my evasion of this dental ailment to my behavior. To make a long story short my dentist disabused me of the notion that dental pathologies are purely a function of dental hygiene and diet. Rather, he explained that many of these ailments exhibit strong family and ethnic patterns, and are substantially heritable. My mother did suffer from periodontal disease a few years back, and that has made me much more proactive of my own dental health.

As someone who is quite conscious of the power of genetics, I was quite taken aback by this blind spot. I realized that not only did I attribute my own rather fortunate dental health (so far) to my personal behaviors, but, I had long suspected those with dental issues of less than optimal habits. Obviously environment (e.g., high sugar diet) does matter. But apparently a great deal of the variation in the trait is heritable. If you are still curious, here’s a paper which might interest you, Heritable patterns of tooth decay in the permanent dentition: principal components and factor analyses.

MORE ABOUT: Heritability

Comments (26)

  1. Heléna

    so agree – anecdotally I have friends who have the barest of cleaning routines and have been told by dentists that they need never come back unless they are in pain as they have no cavities and their teeth do not even show much wear – me with diligent dental hygiene, and a relatively healthy diet not so fortunate

  2. Oh, there’s no question. I have fabulously healthy teeth, and as a child grew up in a country without floride and hated brushing my teeth until I was at least ten.I outgrew that dislike, but I only started flossing seven years ago and am quite unreliable, and I only started getting six month cleanings (as opposed to 2-5 years apart) about three years ago. Yet I only have three cavities, all of them caused by very deep creases in my back molars, and that risk ended when dental sealants came along when I was in my early 20. . My gums are a different matter; they are the reason I finally took up the flossing and the regular cleanings–but even then, the small effort I made immediately improved my gums and cleanings to such an extent that the threat of periodonatal work went away 3 weeks after I was first put in terror of the possibility.

    When my son was born, the ex and I prayed nightly that he would inherit my teeth and the ex’s eyes, and our prayers were granted–he, too, has excellent teeth and 20-20 vision.

    No one should feel smug about their teeth. And really, why does anyone moralize about any aspect of their health these days, be it teeth or weight or cholestrol count? Glad this finally occurred to you. Celebrate by cutting back on the floss!

  3. you assumed there is no variation in enamel quality?? i am surprised you actually had a genetics related blind spot. i had always kind of assumed it was mostly heritable from hearing various stories of people who “never brush their teeth.” that and knowing that for every good dental customer there’s likely 2 that are completely irresponsible (and yet often won’t fair much worse than the good one.) an example of similar genes/different environment would be my anorexic sibling having bad cavity problems while i have very few. i guess it’d take something extreme like that to over power the genetic similarities.

  4. Deb

    In 1st year microbiology prac we took scrapings from our teeth and looked for a bacterium (not sure which, this was last century) associated with caries. Two of us grew agar plates bristling with them, but had no cavities or other dental problems. It was explained to us, but not in genetic terms, something to do with enzymes I think. While I do the right thing by my teeth mostly, still no cavities while the rest of the family keep the dentist in BMWs. Go figure!

  5. Eurologist

    I thought that the gums’ health was mostly determined by the composition of mouth bacterial flora, which is not inherited directly, but rather given by oral contact from the majority of first care providers.

    For example, my mother lost most of her teeth in her 40’s (due to the above and severe WWII and after malnutrition). I also suffer from gingivitis no matter what I do. On the flip side, the gums of my wife and my (at birth) adopted son are just fine. Luckily for him, I just got there a little late.

  6. Cathy

    I’m one of those who had a bad roll of the genetic dice when it comes to teeth. Both my parents had extensive crowns and bridgework by the time they were in their fifties, and my own adult teeth started to disintegrate when I was in my early twenties.

    My dentist said my teeth are soft like cheese, and at this point I have only eight teeth left that have not been substantially altered with a root canal, a crown, or some sort of repair. (One of those is a wisdom tooth that descended after a back molar was extracted, astonishing my dentist.) I’ve been switched over to a prescription toothpaste with five times the fluoride as the regular stuff, which has halted the decay of my remaining teeth, but I’ve had $20,000 worth of dental work so far and it’s not over yet.

    Count yourself lucky if you have good teeth!

  7. ac

    I always feel like I got the short end of the stick: I don’t like sweets, I brush and floss regularly, and have slightly yellowish teeth. In contrast, my wife brushes maybe once per day, eats all sorts of sugars and sodas, and has bright whites. Of course, the same is true of both our sets of parents.

  8. Mark Plus

    Funny, my parents both had plenty of tooth decay growing up. But my sister and I grew up and lived without caries until we reached our 40’s.

  9. ackbark

    I’ve had a lot of dental difficulties, but since I started taking Vitamin D daily about ten years ago I haven’t any whatsoever. Not one cavity, essentially no plaque and no recurrence of gingivitis.

    Also I have not had one cold, one flu or one sore throat. Honestly, Vitamin D is a miracle.

  10. Jacob

    I don’t have much of a sweet tooth either. But I’ve found that grain consumption seems to affect dental health as well. When I’ve been on “paleo” or “low-carb” diets, I’ve noticed my teeth being cleaner and less sticky, similar to the difference between when I consume lots of sugary stuff and when I don’t. This is anecdotal of course.

    There is other anecdotal evidence suggesting that environment via nutrition significantly affects dental health.

    Tyler Cowen cured his gum disease and was able to avoid invasive surgery through Omega-3 supplementation via flaxseed oil:

    There is also some experimental evidence in addition to anecdotal:

  11. Dm

    #3, the microbiome could be substantially maternally heritable even if babies are given up for adoption?

  12. Isabel

    ” I had long suspected those with dental issues of less than optimal habits”

    Being from a population that is, like the British, known for “dental issues,” (not just tooth decay but misalignment -supposedly they are related), I have often been struck by the amazingly beautiful smiles of the poor and downtrodden around the globe. Sounds like your “blind spot” was simply a result of your good fortune so far.

    I’m not sure if it’s a perception issue, because my teeth always look better and it’s easier to overlook flaws when I’ve been out in the sun and have some color, but less than dazzling, misaligned teeth also seem more common among east asians. Also smaller chins- maybe these are all connected?

    Just noticed ackbark’s comment; all of the above observations could be latitude/vitamin-D related perhaps.

  13. marcel

    What a pain in the ass, having a vanity related blind spot pointed out. Not only do you lose a reason to feel good about yourself, you gain a reason to feel bad. Maybe, analogous to Bullwinkle here (FF to 48 seconds) you gotta get another dentist!

  14. ackbark

    One thing I’ve always wondered about is why do Neanderthal skulls always seem to have perfect teeth?

    Buried in the dirt for 50,000 years and they still have better teeth than I do!

  15. Nocturnal chomping and tooth grinding (aka bruxism) doesn’ t add to dental health either. Keeps the dentists in condos, Bali breaks, and SUVs. tho’. Yay for free enterprise and dental access for the monied class.

  16. Sandgroper

    #14 – Hunter-gatherers. The same was noted by early investigators of Australian Aboriginal people – very healthy teeth. This is heavily influenced by diet, and by tobacco and alcohol use (which can be big factors in gum disease). So this is a genes+environment issue. (And frankly, what isn’t?)

    #12 – The misalignment is a genetic issue in East Asians – often the teeth are too crowded: teeth too big/jaws too small. It does *not* seem to result in a noticeably high rate of decay.

  17. April Brown

    My poor son, at the age of 2 1/2 (despite us doing brushing and flossing and all that, and having a pretty healthy and largely sugar free diet), just had to get general anasthesia and have 4 caps, 8 fillings, and a root canal on his baby teeth. Just heartbreaking – of course the first few years of his life were in Algiers (which doesn’t floridate the water), but still. We have to use extreme prescription toothpaste on him, which is tricky because it’s toxic for somebody that young to swallow.

    Dentist told us his gums showed that he was being well cared for in terms of diet and hygiene, but that his enamel was just prone to failure. I’m really hoping his adult teeth will be a little stronger, but who knows.

  18. Eurologist

    Not sure if you meant me instead of #3, but what is the vector for that? Mouth-to-mouth contact instead seems so straightforward. BTW, I like mouth-on-mouth (semi-obscure Jean Aurel reference).

  19. GH

    So far it seems that one out of our four kids inherited the weaker teeth of three grandparents and one parent. He’s already had fillings and a pulpectomy on baby teeth, and he’s the one that we still manage the brushing and tooth care on. It’s frustrating that we take the most care with his teeth, and his are the worst cavity-wise. We truly hope our other three kids have inherited their dad’s super strong, never a cavity teeth, instead of mine- lots of fillings and extractions for space.

  20. Dental Hygienist

    As a dental professional, heridity does have something to do with how your teeth react to cavities and decay, but your diet has a HUGE impact. Sugar is not the only detrimental food for you to watch out for. Fermentable carbohydrates and other sticky foods that stay in your mouth for an extended period of time have a lot to do with decay as well as acid in drinks. Also, parents who put their child’s pacifier in their mouth or eat off of the same spoon are introducing bacteria to the mouth that the teeth and oral cavity are not prepared for at such a young age. Cavities ARE contagious. Home care is not enough to ward off cavities. Enamel can be genetically weak leading to dental problems in younger people. Just some food for thought! 🙂 Also, the reason bruxism, or grinding, has an impact on dental health is because it can lead to TMJ, destruction in enamel, and destruction of tooth structure. All of these are detrimental to oral health. Enamel is what protects the teeth from cavities. Also, grinding can lead to sensitivity of the teeth due to the dentin, or layer beneath the enamel, being exposed to air and fluid movement. People without insurance or with limited insurance have access to clinics and schools for lower dental costs to ward off disease, cancer, and cavities. Early intervention is the BEST way to prevent cavities especially for children.

  21. John Emerson

    It’s not necessarily the teeth themselves. My son and I have a condition called “sour mouth” which has multiple causes (acid reflux, diet, bacteria, and the way the mouth enzymes process food) and wonder whether it is partly hereditary. (“Sour mouth” is also used for bad breath, but this is different). My whole family has terrible teeth, with widely varying care practices.

  22. pconroy

    I had overcrowded teeth as a kid and so had to have 4 removed. Other than that I have fairly large teeth with very strong enamel and very deep roots.

    I have a definite sweet tooth and eat some candy daily, and also often eat some candy in bed at night, after I’ve brushed my teeth. But no caries to worry about.

    I visit the dentist maybe every 2-3 years. Last time there the dentist said, “Your teeth are looking great, keep up the brushing and flossing”. He was surprised when I told him that I had never ever flossed my teeth. So he asked me how I keep them so clean, and I told him that I learned in Elementary school – at 7 yo – how to brush teeth properly, which is to use a rotating motion away from the gum, towards the tooth tip, and I have done so ever since…

    I think most Americans brush their teeth horizontally, and this is incorrect, as it forces food particles between the teeth?!

  23. T

    Part of it has to do with the geometry of your teeth. If you have places for things to collect you’re going to be worse off.

    Personally I have poor dental hygiene and I get some minor cavities. However they never become serious, even if left unattended. I forgo novocaine because they are shallow so the drill doesn’t hurt me.

  24. ackbark

    16. Not just the healthiness of the teeth but their perfect alignment. Seemingly nothing gone astray, no overbites or underbites.

  25. Justin Giancola

    Like 20 implicated, starchy foods that form a paste that sticks to your teeth are much worse than suckers and icecream.

    An example from my personal life: I spent a year living in Canada with my Middle Eastern friend’s family; the food was homecooking “healthy” everyday, but it was often rice based dishes or lots of starchy vegetables. I noticed that I was getting WAY more plaque build up than I ever did eating my relatively run-of-the-mill American grub; and this reverted back to normal as soon as I returned home, and to my less cultured cuisine. Food for thought…ho ho ho ;p

  26. Blanca

    Have a peek through the NOHSS,

    Skimming through the data, my first impression is that there’s not the correlation I expected between state (as a proxy for social and economic difference) and poor dental hygiene – eg, West Virginia and Massachusetts have roughly similar rates of treated or untreated dental caries among 3rd graders. Regional diet preferences?


Discover's Newsletter

Sign up to get the latest science news delivered weekly right to your inbox!

Gene Expression

This blog is about evolution, genetics, genomics and their interstices. Please beware that comments are aggressively moderated. Uncivil or churlish comments will likely get you banned immediately, so make any contribution count!

About Razib Khan

I have degrees in biology and biochemistry, a passion for genetics, history, and philosophy, and shrimp is my favorite food. In relation to nationality I'm a American Northwesterner, in politics I'm a reactionary, and as for religion I have none (I'm an atheist). If you want to know more, see the links at


See More


RSS Razib’s Pinboard

Edifying books

Collapse bottom bar