Holes in your mouth usually come down to one of a few common causes: cavities in your teeth, ulcers on your soft tissue, pockets along your gumline, or the natural folds in your tonsils. Less commonly, a hole can appear in the roof of your mouth or linger after a tooth extraction. The location, size, and any pain you’re feeling narrow down what’s going on.
Cavities: The Most Common Cause
A cavity is literally a hole in a tooth, and it’s the single most likely explanation. About one in five adults between ages 20 and 64 has at least one untreated cavity right now. Cavities form when bacteria in your mouth feed on sugars and starches from food, producing acid that strips minerals from your tooth enamel. At first, the damage shows up as a white spot on the tooth surface. At that early stage, the process can actually be reversed with fluoride and better oral care.
If the acid exposure continues, the enamel breaks down completely and a physical hole forms. Early cavities often cause no pain at all, which is why many people discover them by feel (running their tongue over a tooth) before they notice any discomfort. As decay deepens past the enamel into the softer layer underneath, you may start feeling sensitivity to sweets, hot drinks, or cold foods. Left untreated long enough, bacteria can reach the inner pulp of the tooth and cause an infection called an abscess, which brings throbbing pain, facial swelling, and sometimes fever.
Canker Sores and Mouth Ulcers
If the hole is on your inner cheek, lip, tongue, or the floor of your mouth, and it’s painful, you’re probably looking at a canker sore (aphthous ulcer). These are shallow, round or oval craters with a yellowish-grey center and a red border. They tend to first appear during adolescence and can recur throughout life.
Minor canker sores are small, typically under 4 millimeters across, and heal on their own within 10 to 14 days. Major canker sores are larger than 10 millimeters, can last up to six weeks, and sometimes leave a scar. They’re not contagious and aren’t caused by a virus, though stress, minor mouth injuries, acidic foods, and certain nutritional deficiencies can trigger them. Most need no treatment beyond over-the-counter numbing gels or saltwater rinses.
Gum Pockets From Periodontal Disease
If the holes seem to be between your teeth and gums, or if your gums feel like they’re pulling away from your teeth, you may have periodontal (gum) pockets. Healthy gums sit snugly against the tooth with a gap of only 1 to 3 millimeters. When plaque builds up and hardens along the gumline, it irritates the tissue and causes it to detach, creating deeper pockets.
Pockets of 4 to 5 millimeters indicate moderate gum disease. Pockets 6 millimeters or deeper signal severe periodontitis, where the bone supporting your teeth is actively breaking down. You might notice bleeding when you brush, persistent bad breath, or teeth that feel slightly loose. Unlike cavities, gum pockets aren’t always visible to you, but you can sometimes feel them with your tongue as gaps or soft spots at the base of a tooth. A dentist measures pocket depth with a thin probe during a routine exam.
Holes in Your Tonsils
If you’re seeing small holes or crevices at the back of your throat on either side, those are tonsillar crypts. They’re a normal part of tonsil anatomy, but they can become enlarged and more noticeable after repeated tonsil infections. These folds trap dead cells, food particles, and bacteria, which can harden into small, pale lumps called tonsil stones.
Tonsil stones are usually harmless but can cause bad breath, a feeling of something stuck in your throat, or mild soreness. Many people dislodge them on their own by gargling or gentle pressure with a cotton swab. If you’re getting tonsil stones repeatedly, it’s a sign your crypts have grown larger, typically from a history of tonsillitis.
A Hole After Tooth Extraction
If you recently had a tooth pulled, the socket left behind is an open hole that heals gradually. Within the first few days, a blood clot forms to protect the bone underneath. Over the next four weeks, that clot is replaced by soft granulation tissue. Full healing of the bone and soft tissue takes roughly six months, though the visible hole closes well before that.
The main risk during early healing is losing the blood clot, a painful condition called dry socket. Smoking, drinking through a straw, or vigorous rinsing in the first 48 hours can dislodge it. If you develop intense, radiating pain two to four days after an extraction, that’s the most common sign.
Normal Anatomy You Might Be Noticing
Not every opening in your mouth is a problem. Your salivary glands empty into your mouth through small ducts that can look like tiny holes. One sits on the inside of each cheek, roughly across from your upper second molar. Another pair opens under your tongue, near the midline. These are completely normal and you may only notice them when they’re slightly swollen or when you feel a small jet of saliva during eating.
Holes in the Roof of Your Mouth
A hole in the hard palate (the roof of your mouth) is uncommon and worth taking seriously. Possible causes range from cocaine or other drug use, which can erode the tissue, to autoimmune conditions like lupus or granulomatosis with polyangiitis (formerly called Wegener’s). Certain infections, including tuberculosis and syphilis, can also cause palatal perforations. Occasionally, a hole forms after an upper tooth extraction if the root was close to the sinus cavity, creating a passage between your mouth and sinus. A hole in the roof of your mouth that wasn’t there before needs professional evaluation.
When a Hole Needs Attention
Any sore or lesion in your mouth that hasn’t healed within two weeks after you’ve removed obvious irritants (sharp food, a rough tooth edge) should be looked at by a dentist or doctor. This is the standard threshold clinicians use to decide whether a biopsy is needed. Red or red-and-white patches that don’t go away, sores that bleed easily, lesions that feel hard or fixed to deeper tissue, and any new or changing pigmented spot all raise the concern for something more serious. Rapid growth is another warning sign.
For canker sores specifically, an ulcer lasting longer than three weeks should prompt a specialist referral to rule out malignancy. Most mouth holes turn out to be cavities, ulcers, or normal anatomy, but the two-week rule is a reliable guide for deciding when to stop waiting and get it checked.