Did I give my boyfriend cavities?
April 30, 2012 7:55 PM   Subscribe

I had untreated cavities. Now my boyfriend has cavities and his dentist blames me and says we shouldn't kiss. To what degree is this true?

I've had cavities for about a year and finally started to get them filled. My boyfriend of a year has a history of cavities but was fine for a while. This visit and last he's had cavities.

We don't exactly have five star oral health: He water flosses and brushes with a manual toothbrush once a day in the morning. No string flossing, coffee or soda, but he does drink smoothies. I've brushed/water flossed at night. I'm obviously stepping up my oral hygiene game.

I've read about the contagiousness of cavity-causing bacteria, but it seems like cavities only thrive if habits allow them to. My boyfriend, however, is pretty upset.

Any studies about this? How much responsibility should I take? And can we still kiss?

Longtime lurker, first time poster- thanks Metafilter!
posted by elklet to Health & Fitness (22 answers total) 9 users marked this as a favorite
Like, you shouldn't kiss forever into the future? This seems a high cost for a low risk activity.

Of course, some bacteria are 'swapped' during kissing, but as I understand it many of the bacteria that cause cavities must enter a pathogenic life phase (i.e., become numerous enough and create a biofilm on the teeth) before they can cause a cavity.

My husband has had a lot of cavities during our ~20 yrs together. I've had one. We kiss a lot. I'd want to see more data from the dentist before we change our behavior. Other Mefites???
posted by Tandem Affinity at 8:03 PM on April 30, 2012 [1 favorite]

I'm not a dentist, but I happen to be super cavity prone (my mouth looks like a chrome graveyard). I let some issues in my mouth go for a long time, like years, which ended up in extremely painful infections and four root canals. All this happened about the same time I got married, so being newlyweds I kissed my wife lots and lots. We also have not the best habits ever* (only brushing once a day, just before bed, flossing maybe once a month) and my wife has a major sweet tooth.

Couple all that with my bacteria laden kissing and the fact that she went a year without seeing a dentist and when she finally did? No cavities. Not a single one. I suspect there's more to this cavity thing then swapping spit.

*FYI four root canals is no picnic and I now hardcore floss almost every single day.
posted by Doleful Creature at 8:05 PM on April 30, 2012 [3 favorites]

By more data, I mean, I'd like your dentist to prove that your mouth is a particularly rich source of pathogenic bacteria and that, in the absence of kissing you, your boyfriend's mouth becomes rather sparse in terms of pathogenic bioburden.
posted by Tandem Affinity at 8:06 PM on April 30, 2012 [3 favorites]

Did the dentist tell you this, or did your boyfriend tell you the dentist told him?

Because I think the others above are likely correct that you aren't causing the cavities.

But untreated cavities *can* cause really terrible bad breath-- so it might be possible your boyfriend (or his dentist) is trying to gently let you know to fix the problem. (Of course they can also cause all sorts of other things for your own health, but you presumably know that).
posted by nat at 8:10 PM on April 30, 2012 [7 favorites]

i think it could be good motivation for both of you to up your oral hygiene. make a rule: if you want to kiss you both have to brush your teeth first.

cavity causing bacteria have been in your mouth, are still there, and will always be there, weather you kiss your boy friend again or not.
posted by cupcake1337 at 8:12 PM on April 30, 2012

This totally sounds like a load of crap to me. Cavities are not a cold.
posted by jenfullmoon at 8:17 PM on April 30, 2012 [4 favorites]

I believe recent research does indicate that cavities can be contagious, but only from tooth to tooth, not mouth to mouth.
posted by These Birds of a Feather at 8:20 PM on April 30, 2012

Besides countless other benefits beyond strengthening bones, and by extension of that, teeth, I'd recommend taking a vitamin D supplement.
posted by Ryogen at 8:29 PM on April 30, 2012

jenfullmoon: "This totally sounds like a load of crap to me. Cavities are not a cold."

No, but caries can be very much like one.

Dental caries, the disease that produces cavities, are caused by bacteria, which are indeed communicable. So you do make an at least plausible etiology for your boyfriends cavities.

Cavities happen when bacteria like Streptococcus mutans form biofilms on your teeth and ferment sugars into acidic byproducts. Your teeth are acid sensitive and are chemically degraded by it. With the advent of high-throughput sequencing, there is a lot of really cool new research looking into the kinds of strains that most populate those biofilms and the kinds of strains that have the most effect on tooth decay and caries. I don't know of any researchers who have looked at transmission of caries between adult partners, and have just done some searching, but there is a lot of research looking into how transmission of adult mouth flora to infants affects their likelihood of getting caries.

If you've got a particularly caries prone mouth flora, and particularly if you maintain a healthy population of it, that could easily have meaningful effects on your boyfriends oral health.

Really though AskMetafilter is the wrong forum to ask this question, you have gotten, and will get a lot more, answers from folks who are precisely as unknowledgeable about dental microbiology as you are. We all have teeth so we're all experts. This guy is a dentist who seems like he'd have a lot of fun with your question.

I am a microbiologist, I am not your microbiologist, this does not constitute dental advice. I am also not a dentist and I have no dental training, but I love population microbiology and I once had a lot of fun demonstrating that the cure all my field has to offer dentistry will probably never be more effective than mouthwash.
posted by Blasdelb at 8:30 PM on April 30, 2012 [17 favorites]

Time magazine article. NY Times article. Myth v. Facts:

Saliva and the mouth are full of viruses and bacteria, including some that cause cavities. Kissing a partner who is actively infected with cavity-causing bacteria can cause a person who previously had a low concentration of these bacteria to ‘catch’ a cavity, due to the extra dose of bacteria from kissing—particularly if that person has poor oral habits that set the stage for tooth decay
posted by jabberjaw at 8:31 PM on April 30, 2012 [4 favorites]

If you really want to be vigilant about it, you could always get in the habit of using mouthwash before and after you make out. Rinsing after you wake up and again before bed is a great way to reduce your bacterial count, in any event. Works for me!
posted by doreur at 8:54 PM on April 30, 2012 [1 favorite]

Use these to floss. Plackers disposable flossups. Don't buy the other brands, they fall apart more or less instantly (at least if your teeth are really tight together like mine).

I used to floss very very seldomly, partially because it was so damn hard with my tightly spaced teeth. Now I floss complusively almost, certainly after every meal. The plackers make it that convenient. And you really start to notice any leftover food junk and you just start needing to get rid of it.

My dental health has skyrocketted since I started plackering. And get a Sonicare toothbrush. Incredibly great.
posted by Chekhovian at 9:12 PM on April 30, 2012 [3 favorites]

Kissing is well worth a cavity. maybe 2. You might want to add a rinse to your dental habits, to reduce bacteria. But, seriously, giving up kissing? The mental health benefits of lots of smooching are pretty significant. I am not a love doctor, and I am not your love doctor, but this does constitute relationship advice: Smooch lots, Hug lots, Have lots of (consensual, of course) good sex, and try to have some really excellent sex. with kissing.
posted by theora55 at 9:18 PM on April 30, 2012 [2 favorites]

My husband has pretty bad teeth. I had excellent teeth-- no cavities ever, excellent check ups, etc. Within a year of moving in with him, I had my first cavity ever with no change in dental hygiene habits.

Yeah, I kind of blame him. But I still keep kissing him.
posted by charmcityblues at 9:22 PM on April 30, 2012 [2 favorites]

FWIW, no dentist has ever found a cavity in any of my teeth in my whole life, and I am pretty sure most of the people I have kissed have had them before. Although I didn't go closely inspecting in their mouths to find out. Even if there is some evidence that the bacteria might be contagious sometimes, it's definitely not like some kind of assured thing and I see no way your bf's dentist could "know" that your bf's cavities were your fault.
posted by cairdeas at 3:09 AM on May 1, 2012

See, I like Blasdelb's answer better than everyone else's. Your dentist sounds like he's probably on the far side of conservative, dentistry-wise, but given Blasdelb's answer, he's not completely insane.

So - he may have just wanted to slap the both of you into better oral hygiene. (giggle - I said 'oral').

Or he may be a super-vigilant OCD dentist.

Will you both die, or at least cause your teeth to fall out and crumble away by kissing? I'd wager not. But if his kissing warning gets you to use listerine in the morning and before you go to bed, at the very least - well, then that's a positive.

Flossing and brushing on top of that? Even better!
posted by rich at 4:10 AM on May 1, 2012

I am not a dentist, but I was a hygienist when I was in college. Cavities happen when food and bacteria get into a crevice of a tooth. Think of how a tooth is formed...there is lots of room for air pockets to occur, especially in the back teeth which are actually four small teeth growing at once to form one tooth when it surfaces. Cavities are simply a bacterial growth that has started to degenerate what is around it. So, no, you didn't give him a cavity. That is insane. I think perhaps your boyfriend is pulling your leg or the dentist is pulling your boyfriend's leg.
posted by Yellow at 5:02 AM on May 1, 2012

"My boyfriend of a year has a history of cavities"

This suggests he has already been colonized with the bacteria necessary for the development of cavities. It is possible that the overabundance of bacteria from your mouth has help the course of infection in his mouth, but as a microbiologist with an interest (but not research focus) in dental pathogens, I've never seen convincing proof of this (though I'd happily be proved wrong). It's true that if you "paint on" high concentrations of bacteria you can induce tooth decay in unfavorable environments animal studies, but like Blasdelb, I've never seen adult transmission studies. Also, since he has had cavities before it is likely that the harmful bacteria have never been fully cleared from his mouth.

As someone who trains future dentists in microbiology, I have first hand experience telling me that most of the students don't take it seriously at all (compared to say, an AP high school class). I've also had dentist tell me straight up crazy stuff, like the time my personal dentist told me that my gingivitis was a sign that I had AIDS. I don't have AIDS, HIV, or any AIDS like symptoms, and that was really inappropriate, as was telling an adult he shouldn't kiss his girlfriend. Sooo dentists would not be my #1 source for updates in dental microbiology.

If he's really worried, adding a brushing before bed makes way more sense than not kissing your girlfriend.
posted by fermezporte at 5:10 AM on May 1, 2012 [2 favorites]

+1 for mouthwash rendering the problem moot.
posted by Citrus at 6:43 AM on May 1, 2012

I just wanted to note that there are good reasons to take this seriously beyond keeping your teeth.

Oral health is incredibly important for your overall health. For example, people who floss have been shown to live significantly longer, and the positive effect is much greater than the negative effect of smoking. Both a lack of flossing and gum disease are associated with heart disease, which doesn't make any sense until you realize that Streptococcus mutans, the bacteria that primarily populates those biofilms that for on teeth, also populates the heart. No one knows how the S. mutans gets there, but it is probably from the mouth somehow.
posted by Blasdelb at 6:53 AM on May 1, 2012 [2 favorites]

One does have to wonder about the stuff in your mouth...do we face the same problems there as in other body parts ie killing "friendly cultures" off unintentionally allows hostile things to colonize it and generate more harm? So maybe there's some kind of ideal yogurt type way to replace the stuff in your mouth with something more friendly?
posted by Chekhovian at 7:45 AM on May 1, 2012

Thanks guys! This has been really helpful. I don't feel as guilty, but I'm getting the rest of my cavities filled ASAP and from now on we are both flossing/brushing/swishing mouthwash up a storm.
posted by elklet at 5:02 PM on May 3, 2012 [1 favorite]

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