Oral cysts

What exactly is an oral cyst?

An oral cyst is a small, closed pocket that develops within the soft tissue of your mouth or inside your jawbone, usually holding fluid or a semi-solid substance. Most are benign (not cancerous) and grow slowly, but they can damage nearby teeth and bone if left untreated.

What are the symptoms of an oral cyst?

Many oral cysts cause no symptoms at all in their early stages and are only picked up during a routine dental check-up or X-ray. As a cyst grows, it can start to cause:

• A lump or swelling on your gum, tongue, lip or inner cheek, sometimes resembling a small blister
• Pressure, tenderness or pain in the area
• Redness or inflammation, particularly once an infection takes hold
• Teeth that feel loose or start to shift out of position
• An unpleasant taste or oozing, once infection is present
• Difficulty chewing, speaking or, with larger cysts, swallowing

What causes oral cysts, and who is at risk?

Oral cysts have several possible causes, and more than one can apply at once.

• An infection or dying nerve inside a tooth, often one that's already had a root canal
• An impacted or unerupted tooth, most often a wisdom tooth
• Trauma or repeated irritation, for example from biting your lip or cheek out of habit
• A blocked salivary gland
• Developmental factors present from an early stage of tooth formation
• A rare inherited condition called Gorlin-Goltz syndrome, which can cause multiple cysts in the jaw alongside other features

Good oral hygiene lowers your risk as cysts are far less common around teeth that are healthy and well cared for. You're also more likely to develop one if you have an impacted wisdom tooth or a heavily treated or root-canalled tooth.

Are there different types of oral cyst?

• Periapical (radicular) cyst: the most common type, developing where a tooth's root meets the jawbone once the nerve inside has died or become infected
• Dentigerous cyst: forms around the crown of a tooth that hasn't come through, most often a wisdom tooth
• Odontogenic keratocyst: a less common but more aggressive type that can regrow after treatment more often than other cysts
• Mucocele: forms in soft tissue such as the lip or inner cheek, usually after an injury or irritation blocks a small salivary gland
• Ranula: a larger version of a mucocele that appears underneath the tongue, caused by a blockage in one of the major salivary glands
• Nasopalatine duct cyst: a less common type that develops in the roof of the mouth close to the front teeth, left over from early tooth development

How are oral cysts diagnosed?

Your dentist will usually start with a clinical examination, looking at the size, colour and location of any lump or swelling. From there, they're likely to recommend:

• A dental X-ray, to see whether the cyst is affecting a tooth root or the bone
• A CT or CBCT (cone beam CT) scan, for a detailed 3D picture of the jaw when more precision is needed
• A biopsy or aspiration, taking a small tissue or fluid sample to confirm the diagnosis and rule out anything more serious

How are oral cysts treated?

Non-surgical treatment

• Watching and waiting, for a small cyst that isn't causing symptoms, with your dentist monitoring it periodically using check-ups and scans
• Draining the cyst with a needle (aspiration), which can ease pressure and help with diagnosis
• Antibiotics, if the cyst has become infected
• Root canal treatment, where the problem stems from an infected or dying tooth nerve

Surgical treatment

• Enucleation: removing the whole cyst along with its lining, done through a small cut in the gum
• Marsupialisation: opening up part of the cyst wall to let it drain and gradually shrink on its own, often used for larger cysts
• Curettage: a thorough scrape of the bone left behind after removal, to lower the chance of the cyst returning, particularly for keratocysts
• Removing the affected salivary gland, for a mucocele or ranula that keeps coming back

These procedures are usually done under local anaesthetic, so they're rarely painful at the time, though the area may feel sore or bruised for a few days afterwards. Healing is generally complete within a couple of weeks, unless the cyst was unusually large or a tooth had to come out at the same time.

When should I see a dentist?

• A lump, swelling or blister-like spot in your mouth that hasn't gone away after a couple of weeks
• A lump that's growing, changing, or starting to cause pain
• Teeth that feel loose or seem to be moving
• Signs of infection, such as swelling, discharge, or a fever

If you've already had a cyst treated, contact your dentist or oral surgeon if you notice worsening pain, bleeding that won't stop, or swelling and discomfort that carries on well beyond the recovery time you were given.