Sore Gums Can Come From Inflammation, Injury, Infection, or a Tooth

Gums can hurt because they are inflamed, injured or infected—but pain felt “in the gum” can also begin inside a tooth. The location, triggers and accompanying changes are more useful than pain intensity alone, although none can confirm the cause without an examination.

If several areas feel sore, plaque-related inflammation is common

Tenderness across much of the gumline, especially with redness, puffiness or bleeding during gentle cleaning, can fit gingivitis. This is gum inflammation associated with bacterial plaque around the teeth. Plaque can harden into tartar, which brushing cannot remove; it requires professional cleaning (NIDCR).

Gingivitis is reversible. Periodontitis, however, involves irreversible loss of the tissues and bone supporting the teeth and must be managed with professional treatment (CDC). Soreness alone cannot distinguish them. Receding gums, loose teeth, a changed bite or pain when chewing make an examination particularly important.

Smoking, diabetes, hormonal changes, some medicines and other health conditions can affect gum-disease risk or how gum tissue responds to plaque. These factors do not establish the cause of an individual episode.

If one small spot hurts, look for a local cause

A clearly defined sore area is less typical of inflammation affecting the whole gumline. Possibilities include:

• Minor injury: vigorous brushing, snapping floss into the gum, biting the area, or eating something hard or sharp can damage the surface. The ADA recommends a soft-bristled brush and gentle pressure to reduce the risk of gum injury (ADA).
• A mouth ulcer: this usually appears as a visible shallow sore rather than swelling centered around a tooth. Most clear within one or two weeks. An ulcer that lasts longer than three weeks, bleeds, or becomes more painful and red should be assessed (NHS).
• Food trapped between teeth: discomfort may be focused between two teeth. Cleaning between the teeth removes debris and plaque that toothbrush bristles cannot reliably reach, but do not force floss or an interdental brush into a painful space (ADA).
• A partially erupted wisdom tooth: gum partly covering a wisdom tooth can trap food and become inflamed or infected, causing pain and swelling at the back of the mouth. This is called pericoronitis (NHS).

Dry mouth can cause a different pattern: widespread dryness or burning, mouth sores and recurrent oral infections. Persistent dry mouth can be a medicine side effect or relate to a health condition, so it is worth discussing with a dentist or doctor rather than relying only on extra water (NIDCR).

A painful gum lump may come from an infected tooth

Tooth decay or an injury can lead to a dental abscess, producing swelling in the gum even though the problem began in or around a tooth. Possible clues include pain centered on one tooth, pain when biting, hot or cold sensitivity, a bad taste, fever, facial or jaw swelling, or difficulty opening the mouth (NHS).

Even if a gum bump drains and the pain eases, a suspected abscess still needs urgent dental care. Do not pop or puncture it; see what a bump on the gums can mean. An abscess requires dental treatment rather than home care alone.

What to do now

• Keep cleaning, but be gentle. Use a soft brush with light pressure. Forceful scrubbing can add injury, while stopping all cleaning allows more plaque to remain. See how to brush along the gumline gently.
• Clean between teeth carefully once a day. If floss repeatedly catches, shreds or causes pain at one site, stop forcing it and arrange a dental check.
• Avoid obvious irritants for a few days. Very hot, spicy, acidic, hard or crunchy foods can aggravate an injured area or ulcer.
• Use pain medicine only if it is normally safe for you. Follow the label, or ask a pharmacist if you are uncertain. Pain relief does not treat an abscess or remove tartar.
• Book a dental appointment if painful or swollen gums persist, keep returning, bleed with gentle cleaning, or occur with persistent bad breath, recession or chewing discomfort. Depending on the cause, professional cleaning, examination of a tooth or another treatment may be needed.

Seek urgent dental care for severe or worsening pain or swelling, fever, pus or a bad taste, facial swelling, or a suspected abscess. Seek emergency medical help for difficulty breathing, speaking or swallowing; substantial mouth or facial swelling; marked difficulty opening the mouth; or swelling, pain or vision trouble around an eye (NHS).