Biting the inside of your cheek with your back teeth is a common, painful experience, technically known as morsicatio buccarum. While an occasional accidental bite is normal, persistent or frequent issues suggest underlying factors causing the soft tissue to get caught between the upper and lower chewing surfaces. The problem is not always dental, but can result from temporary physiological or muscular issues that change how you chew or hold your jaw. Identifying the precise cause is the first step toward finding a lasting solution.
Temporary and Muscular Factors
Involuntary cheek biting often occurs when the muscles controlling the jaw and tongue are not coordinating properly, often due to fatigue or heightened stress. When a person is anxious or stressed, they may unconsciously engage in repetitive behaviors, including chewing on the cheek lining. This habitual, subconscious biting can become a body-focused repetitive behavior.
Chewing food too quickly or talking while eating can increase the likelihood of accidentally catching the cheek tissue. These actions introduce sudden, uncoordinated jaw movements that momentarily position the cheek in the path of the closing teeth. This trauma can lead to a cycle of repeated biting.
When the cheek is repeatedly bitten, the tissue lining (buccal mucosa) can develop a thickened, rough patch known as hyperkeratosis. This thickened tissue is a scar-like response to chronic trauma, making it easier for the teeth to catch and bite this new, slightly more prominent tissue. Additionally, soft tissue swelling, such as from a canker sore or minor injury, can push the cheek further inward, making it an easier target.
How Dental Alignment Causes Cheek Biting
The most common long-term cause of frequent cheek biting is a structural misalignment where the teeth do not properly interlock, medically termed malocclusion. A healthy bite involves the upper teeth slightly overlapping the lower teeth, creating an outward shelf that protects the cheek. If this alignment is compromised, the cheek tissue can be pushed into the space between the back teeth.
Specific types of malocclusion contribute to this issue, such as a posterior crossbite, where the upper back teeth sit inside the lower back teeth instead of outside them. Another element is limited buccal overjet, which describes a lack of horizontal overlap between the upper and lower teeth, removing the protective barrier for the cheek. These misalignments position the cheek right along the occlusal plane, the line where the teeth meet.
Changes to the mouth’s structure can introduce a biting problem, even in an otherwise healthy mouth. Teeth can shift over time due to tooth loss or age, altering the bite plane and creating sharp edges that snag the cheek. Similarly, a dental restoration like a crown or filling that is poorly contoured or positioned can change how the upper and lower teeth come together, creating a new pinch point for the soft tissue.
What to Do About Cheek Biting
If you notice a frequent problem, start with self-care adjustments to minimize trauma. Mindful eating involves slowing the pace of chewing and consciously focusing on the act of eating, which helps the jaw muscles coordinate better. If stress is a known factor, incorporating stress reduction techniques like deep breathing or meditation can help manage subconscious habits.
For an already injured cheek, maintaining good oral hygiene is important to prevent infection. Rinsing the mouth with a warm saltwater solution can help soothe irritation and promote healing of any sores or ulcers. Over-the-counter oral gels can be applied directly to the injured area to provide temporary pain relief.
If the biting is chronic, painful, or you suspect a dental cause, professional evaluation is necessary. A dentist can examine the bite for malocclusion, check dental restorations for rough edges, and determine if an orthodontic issue is the root cause. Solutions may involve smoothing a sharp tooth edge, replacing a faulty restoration, or using a custom-made dental device. For those who bite their cheeks at night, a custom mouthguard acts as a physical barrier to protect the cheek while sleeping.