Imagine: You’re enjoying a little snack break and all of a sudden, you’re not biting down on your delish breakfast bar, but on the inside of your cheek. Ouch! It’s annoying enough when it happens once, but if it keeps happening (especially in the same exact spot) you may wonder, “why do I keep accidentally biting the inside of my cheek?”

Turns out, repetitive cheek biting may not always be an accident; it could point to an underlying oral health issue you didn’t even know about.

Whether it’s a tooth, jaw, or even psychological issue (did someone say stress?), constantly biting the inside of your mouth can be prevented. We tapped two dentists here to learn more about why cheek biting happens, and whether it’s a harmless (or harmful) habit.

1. You have morsicatio buccarum (aka, chronic cheek biting)

If nibbling the inside of your cheek is becoming a habit, you might have morsicatio buccarum. “Morsicatio buccarum is the Latin term for chronic cheek biting, i.e., when people habitually chew or bite the insides of their cheeks,” says Chrystle Cu, DDS, a California-based dentist and founder of Cocofloss.

This chronic condition can develop for multiple reasons, says Marina Gonchar, DMD, orthodontist and founder of Skin to Smile. According to Dr. Gonchar, these can include the following:

• A repetitive behavior due to boredom, stress, or anxiety
• Misaligned teeth
• Irregularities in the oral tissues
• Sharp edges of chipped teeth, fillings, or crowns
• Irritation of oral tissues as a result of poor-fitting appliances (like retainers or dentures)
• Teeth grinding

How to treat it:

Many people with this condition aren’t even aware of their biting habit. The first step is to acknowledge the issue, so you can be conscious about stopping it. Beyond this, treatment depends on the underlying cause. For example, if a chipped tooth is cutting into your cheek, your dentist can repair it, so it no longer catches the fleshy tissue inside your mouth.

2. It’s an accident

In your haste to inhale a quick breakfast before work, you chew with reckless abandon, and crunch, you take a chunk out of your cheek. Yep, that hurts. “Accidental cheek biting is very common, especially if you are in a rush and not paying attention,” Dr. Gonchar adds. It usually happens when you’re talking or chewing (or while doing both at the same time), Dr. Cu says.

How to treat it:

Accidental cheek biting is usually no biggie. But if you bite your cheek hard enough, you could end up with a mouth ulcer, Dr. Gonchar. These sores are usually harmless and take a few days to heal. In the meantime, you might need to be extra careful when chewing to avoid reopening the area. Slow, careful chewing is also just a good general rule; it can help prevent accidental cheek biting in the first place.

3.Your teeth aren’t aligned properly

Turns out, straight teeth don’t just create a beautiful smile. They’re also important for your oral health. Case in point: they can prevent cheek biting.

“Chronic cheek biting is more likely if your bite [i.e., the way your upper and lower teeth fit together] is misaligned,” Dr. Cu says. Here’s why: “When the teeth do not meet properly, overlap too much, or are crowded, the oral tissues can easily get caught between the top and bottom teeth during routine tasks such as speaking or chewing,” Dr. Gonchar says.

Misaligned teeth—also called malocclusion—can cause other problems, too. Symptoms can include the following, per Mount Sinai:

• Difficulty or discomfort when biting or chewing
• Speech difficulties (rarely), including lisp
• Mouth breathing (i.e., breathing through the mouth without closing the lips)
• Inability to bite into food correctly

How to treat it:

If you’re teeth aren’t properly aligned and they are causing problems, reach out to an orthodontist—a dentist who specializes in aligning your bite and straightening your teeth. They can take a look at your teeth and recommend treatments options, which may include the following, per Mount Sinai:

• Regular or clear braces (like Invisalign), and removable retainers
• Removing one or more teeth (if overcrowding is part of the problem)
• Repairing rough or irregular teeth (teeth may be adjusted down, reshaped, and bonded or capped)

4. It’s a jaw issue

Jaw problems can cause tooth misalignment, too, Dr. Gonchar says. As we know, when your teeth don’t fit correctly, you have a greater risk of cheek biting. On top of this, “significant jaw deviations are often accompanied by a clenching and grinding habit,” she says. Both can result in chronic cheek biting.

Other possible jaw issues include the following, per Mount Sinai:

• Misalignment of jaws after a severe injury
• Tumors of the mouth and jaw
• The jaws are misshapen
• Difference in size between the upper and lower jaws

How to treat it:

Your best bet is to see an orthodontist for this, too. They might recommend braces, a mouthguard (to protect your teeth if your grind them), or other dental appliances to manage your jaw problems. In severe cases, you might need surgery to lengthen or shorten the jaw, according to Mount Sinai.

5. It’s psychological

Gnaw on your cheek when you’re nervous? Stress or anxiety can exacerbate your cheek biting problem, Dr. Cu says. During periods of high stress or anxiety, cheek biting can serve as a coping mechanism for some people, Dr. Gonchar adds.

Cheek biting can also become a repetitive behavior. And it can happen with certain mental health conditions that involve compulsive behaviors, Dr. Gonchar says. Some examples she cites are:

• Obsessive-compulsive disorder (OCD): A condition that causes frequent unwanted thoughts and obsessions that drive you to perform repetitive behaviors (i.e., compulsions).
• Body-focused repetitive behaviors (BFRBs): Any self-grooming behavior that damages the body. The most common BFRBs are skin picking, nail biting, and hair pulling, according to the Mayo Clinic.

How to treat it:

If stress or anxiety is triggering your cheek biting, it’s important to take stock of your mental health. You may want to open up to a trusted health-care provider or therapist about how you’re feeling. With time, practice, and therapy, medication, or a combination of both, you can move through unwanted thoughts, feelings, and behaviors that contribute to cheek biting.

6. You have irregularities in the soft tissues of the mouth

When the fleshy insides of your cheek become swollen or inflamed, they can grow larger and get in the way when you’re talking or chewing. Translation: you’re more likely to snag your tooth on these soft tissues. Possible irregularities in the soft tissues of the mouth can be the following, per Dr. Gonchar:

• Swelling from a clogged salivary duct
• Benign intraoral swellings and growths
• Malignant growths (in very rare instances)

How to treat it:

“In all scenarios, it is important to see your dentist for evaluation and treatment,” Dr. Gonchar says. “Not only to eliminate the chronic cheek biting, but also to ensure the underlying condition is not a cause for concern.”

Is cheek biting harmful?

While “occasional cheek biting can be annoying and painful,” it’s usually not harmful in the long term, Dr. Cu says. “The soft tissue inside our mouths (aka, our oral mucosa) typically heals from injury within a couple of weeks,” she says.

But habitual cheek biting is bad news. Repeated, frequent, or chronic cheek biting may cause ulcers, bleeding, infections, tissue scarring, and erosion, Dr. Gonchar says. These problems can damage your oral and, possibly, overall health, she says. This is why it’s important to treat and prevent cheek biting (more on this next).

How to stop or prevent cheek biting

If you want to put an end to your cheek biting habit, try these tips from Dr. Gonchar and Dr. Cu:

• Be mindful of the habit: Cheek biting is often subconscious. To kick the habit, you must first pay attention to this repetitive behavior (especially during times of stress).
• Chew food carefully and slowly: This will help avoid accidental cheek biting during meals.
• Maintain good oral hygiene: Taking care of your mouth ensures cheek biting isn’t a result of dental issues such as calcium buildup or broken fillings, crowns, or chipped teeth.
• Wear a mouthguard when you sleep: This is especially important if you grind or clench your teeth at night.
• Use effective stress-management techniques: If you think your cheek biting is stress-related, find something to do to relax, like deep breathing, meditation, or exercise.
• Try chewing sugar-free gum: This will help keep your mouth occupied, especially if cheek biting is habitual.
• Train your oral muscles and posture to do something else: For example, rest your tongue firmly on the roof of your mouth, keeping your teeth touching ever-so-slightly and your lips closed. In this position, practice breathing in and out through your nose. Breathing like this also has the added benefit of increasing nitric oxide production, ultimately helping you get more oxygen in your bloodstream.
• See an orthodontist: If cheek biting is related to improper alignment of the teeth or jaw, orthodontic treatment can help eliminate any underlying structural issues.

When to see a dentist about chronic cheek biting

You don’t need a trip to the dentist for the occasional cheek biting incident. But if you repeatedly bite your cheeks while stressed, eating, or talking, it might be time to make a dental appointment. It’s worth having a dental professional take a look in your mouth if you have the following symptoms, according to Dr. Gonchar and Dr. Cu:

• The skin inside your cheeks is painful or not healing, and the discomfort interferes with your daily life
• You have continuous damage to the inside of your mouth, like sores, inflammation, or bleeding
• You have difficulty speaking or eating

Your dentist will take a look at your teeth and jaws to figure out if an underlying condition (like malocclusion) is at play. Once they get a good look—and you explain your symptoms—they can help come up with a treatment plan to hopefully stop your cheek biting for good (or at least, make it happen less often).