Why Is My Gum Covering My Back Tooth?

Your gum can cover your back tooth when the tissue grows over it, and this usually happens for one of two reasons. The most common is a condition called pericoronitis, where the gum flap partially covers a tooth that is still coming in, most often a wisdom tooth. The other is simple overgrowth of gum tissue, which can occur from irritation, certain medications, or even genetics. In both cases, the tissue creates a pocket that traps food and bacteria, which can lead to pain, swelling, and infection if not managed properly.

What Causes the Gum to Grow Over a Back Tooth?

Gum tissue does not randomly decide to cover a tooth. There is always a trigger. The two main culprits are an erupting tooth and tissue overgrowth.

When a tooth breaks through the gum line, it sometimes does not come in completely straight. This is especially true for wisdom teeth, which often come in at an angle. When that happens, a flap of gum stays draped over part of the crown. This flap has a clinical name: the operculum. It creates a space where food and plaque collect, and because it is deep and hard to clean, it frequently becomes inflamed.

The other cause is actual tissue growth. Gums can enlarge for several reasons. Chronic irritation from a rough tooth edge, a poorly fitting crown, or aggressive brushing can make the tissue thicken. Hormonal changes, particularly during pregnancy, can also cause gum swelling. Certain medications, including some used for seizures and high blood pressure, list gum overgrowth as a known side effect. In rare cases, the growth is genetic.

Why Is My Gum Covering My Back Tooth and Causing Pain?

Pain is the symptom that drives most people to ask this question. The pain usually comes from inflammation or infection inside that trapped pocket.

When the gum flap covers a partially erupted tooth, bacteria thrive in the space between the tooth and the tissue. The body responds with an immune reaction. That response brings blood flow to the area, which causes the gum to swell, turn red, and hurt. This condition is called pericoronitis. It can be acute, meaning it flares up suddenly and hurts intensely, or it can be chronic, meaning it causes a dull ache and mild swelling that comes and goes.

In more serious cases, the infection can spread. You might notice a bad taste in your mouth, pus draining from the area, or swelling in your jaw and cheek. Some people develop a fever or find it hard to open their mouth fully. These are signs that the infection is moving beyond the gum tissue, and they require prompt dental attention.

How Is This Condition Diagnosed?

A dentist will look at the area and take an X-ray. The X-ray is essential because it shows what is happening below the gum line.

The dentist checks whether the tooth is positioned correctly or if it is angled into the neighboring tooth. They also look for signs that the tooth is impacted, meaning it is stuck and cannot fully emerge. The X-ray reveals the shape and depth of the tooth roots and whether there is any bone loss around the area.

Your dentist will ask about your symptoms and your medical history. This matters because the treatment plan depends on the underlying cause. A gum flap over an erupting wisdom tooth is managed differently than gum overgrowth caused by a medication.

What Are the Treatment Options?

Treatment depends entirely on the cause and severity. There is no single fix that works for everyone.

For mild cases of pericoronitis, the first step is cleaning. A dentist can irrigate the pocket to flush out trapped food and bacteria. You may be advised to rinse with warm salt water at home. If there is an active infection, antibiotics may be prescribed. These steps relieve the acute symptoms, but they do not solve the underlying problem.

If the gum flap continues to cause repeated infections, the dentist may recommend a minor procedure called an operculectomy. This involves removing the flap of tissue so the tooth is fully exposed. It is a simple procedure done with local anesthesia, and healing is usually quick.

When the covering tooth is a wisdom tooth that is poorly positioned, the more common recommendation is extraction. Removing the tooth eliminates the problem entirely. There is no more flap, no more trapped food, and no more infection risk from that tooth.

For gum overgrowth caused by medication, your doctor might adjust the prescription if a suitable alternative exists. Never stop a prescribed medication on your own. Talk to the prescribing physician first. If the overgrowth is from irritation, fixing the source — smoothing a rough filling or replacing a poorly fitting crown — often allows the tissue to return to normal.

Can I Treat This at Home?

Home care can manage symptoms, but it cannot cure the underlying condition.

Warm salt water rinses several times a day can reduce bacteria and soothe irritated tissue. Over-the-counter pain relievers can help with discomfort. Good oral hygiene around the area is important, but be gentle. Aggressive brushing can irritate the flap further.

Do not try to cut or lift the gum tissue yourself. This can cause bleeding, introduce more bacteria, and make the infection worse. A dental pick or any sharp object has no place near an already inflamed gum.

Home treatment is a temporary measure. If the pain persists for more than a few days, or if you notice swelling spreading to your face or neck, see a dentist promptly.

When Is This an Emergency?

Most cases of gum covering a back tooth are uncomfortable but not urgent. Some situations require immediate care.

Seek emergency dental care if you have severe swelling in your face or jaw, difficulty swallowing, difficulty breathing, or a high fever. These symptoms suggest the infection has spread beyond the gum tissue into deeper spaces of the head and neck. This is a serious condition called a fascial space infection, and it can become dangerous quickly.

Trismus, the inability to open your mouth fully, is another warning sign. It indicates that the muscles of the jaw are involved. Combined with pain and swelling, this warrants urgent evaluation.

How Can I Prevent This From Happening?

Prevention is limited because you cannot control whether a wisdom tooth comes in straight. You can control the hygiene around the area.

If you know a tooth is partially erupted, pay extra attention to cleaning that spot. Use a soft-bristled brush and angle it toward the gum line. Some people find a water flosser helpful for flushing out the pocket. These habits reduce the buildup of bacteria that causes inflammation.

Regular dental checkups allow your dentist to monitor erupting teeth and intervene before a problem develops. If your dentist sees a wisdom tooth that is unlikely to come in cleanly, they may recommend removal early, before infection becomes a recurring issue.