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Why Biting Your Nails is Bad for Your Teeth

May 8th, 2015

Dugas Dental Biting Nails 1- Biting your nails can cause your teeth to get chipped. This is definitely the biggest reason to not bite your nails. Chewing on hard fingernails can take its toll on your teeth. Sometimes when bite through a nail, your teeth hit together pretty hard, which could chip a tooth.

Repeated flexing of your teeth’s enamel occurs when you bite your nails and can cause the enamel to fracture or chip. To find out more about enamel and the other layers of your teeth, read The Anatomy of a Tooth.

For most people, chipping a tooth is the only negative effect that biting your nails might have on your teeth. In fact, the book Pediatric Dentistry by Pinkhamstates:

“There is no evidence that nail biting can cause…dental change other than minor enamel fractures.”

However, various studies have shown that nail biting can cause other oral problems. Keep in mind that some of the following negative effects are very rare and won’t always occur with everyone, so you might want to take them with a grain of salt!

2 – Biting your nails can cause a diastama — a gap between your two front teeth. If the nail biting habit begins when the child is very young, it has been reported to cause a gap between teeth. While I was unable to find a study to confirm this, I did find a dentist has a a picture of it on his website here. While this can occur, it probably won’t unless someone is constantly shoving their nail up between their teeth.

3 – Nail biting can cause the roots of your teeth to become weaker. Nail biting during orthodontic treatment (braces) has been shown to cause root resorption, which is when parts of the roots of your teeth get dissolved by the bone surrounding them. This causes the roots of the teeth to become weaker. Here’s one study and another one that explain this phenomenon.

4 – Biting your nails can cause you to lose your teeth. This study claims that biting your nails can cause you to lose your teeth. Remember — this is the only study that I’ve found that claims this, and we definitely would need more studies to be done in order to verify this. See my disclaimer above!

5 – Biting your nails can cause TMJ problems. This study tells how biting your nails can cause disk displacement in the temporomandibular joint. If you have pain in your TMJ, perhaps it is being caused by your fingernail biting habit.

6 – Biting your fingernails can cause gingivitis. This case report (PDF file) details the story of a young child that bit his fingernails and then shoved them up between his gums and teeth. The report even has pictures if you’re curious. You would think that this would be pretty rare but it might not be as uncommon as you’d think. Here’s another report and one more here! It does go to show that kids can think of anything to do with their fingernails after they’ve chewed them off of their fingers.


I have talked about some of the extreme cases of biting your nails. Obviously, many people do bite their nails without any dental problems. Sometimes, however, people do develop problems.

One interesting fact I found while researching for this article is that biting your nails actually contaminates your mouth with interesting varieties of bacteria that are found on your hands. Since I’m a slight germophobe (as mentioned here and here), this tidbit encourages me keep my nail biting habit in remission.

Hopefully the information provided above can give you the encouragement you need to help you to kick your fingernail biting habit. Or, maybe you’re willing to take the risk and keep on biting your nails.

Have you ever hurt a tooth or had any dental problems due to biting your nails? Please share your comments below!

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