There's a bone-hard lump in my mouth: is it a torus or something else?

A torus is a benign overgrowth that grows slowly from the hard layer of bone on the surface of the jaw. Cleveland Clinic writes that a palatal torus almost always forms in the middle of the hard palate, that it may be present from birth or develop over time, that it is harmless and that it usually does not hurt. A mandibular torus grows from the bone on the inner side of the lower teeth, under the tongue; it can be on one side or both. The tissue covering it is thin and the same colour as the rest of the mouth; when you press on it with a finger you feel bony hardness underneath, and the lump does not move.

How common it is varies a great deal between populations. Cleveland Clinic writes that 20 to 30% of the general population have a palatal torus and that it is more common in women and in people of East Asian, European and West African descent; in the US, it reports a mandibular torus in about 27 in every 1,000 adults and adds that about 80% of these are on both sides. Among 618 dental patients examined at a university hospital in Jordan, the picture was different: 38.7% had a bony growth in the mouth; a mandibular torus was found in 25.7%, a palatal torus in 15.4% and exostoses in 14.4%, and 81.1% of the mandibular tori were on both sides. In other words, if you have one, you are probably not alone.

The cause is not fully known. Cleveland Clinic lists family history, the way the teeth meet and the shape of the jaw, bone density, being over 30, and clenching and grinding the teeth among the risk factors. The link with clenching is often mentioned, but the evidence for it is weak: a systematic review pooling five observational studies writes that abnormal tooth wear may be associated with tori, particularly mandibular tori, that there is not enough evidence for a link with other signs of clenching and grinding, and that the quality of the evidence is low to very low. In the Jordanian study, too, bony growths were seen most in people in their forties and in patients with tooth wear, clenching or grinding.

There are four clues for recognising a torus at home: location, symmetry, hardness and time. A palatal torus sits right on the midline of the palate, as a ridge running from front to back or a lobed bump. A mandibular torus forms lumps on the tongue side of the premolars, usually of similar size on both sides. Both are as hard as bone, the tissue over them is not red, white or sore, and over the years they either do not change at all or grow very slowly. If one of these four clues does not fit, that is, if the lump on the palate is to one side of the midline, the lump in the lower jaw is somewhere other than the tongue side of the teeth, it is soft or rubbery, or it has grown noticeably in recent weeks, do not assume it is a torus.

First among the hard lumps that do not behave like a torus are salivary gland tumours. There are many minor salivary glands in the palate and inside the mouth, and MSD Manuals writes that tumours arising from the minor salivary glands are more likely to be malignant than those of the major glands. Most of these tumours start as a painless, slow-growing, usually firm lump. MSD notes that malignant ones can grow quickly or have a sudden growth spurt, can be fixed to the surrounding tissue with poorly defined edges, can over time cause the tissue over them to ulcerate, and can cause pain and numbness when they spread to a nerve. A painless hard lump growing on the palate to one side of the midline therefore needs to be examined.

The NHS lists a lump in the mouth or on the lip, a mouth ulcer lasting more than 3 weeks, a red or white patch in the mouth, pain that does not go away, difficulty swallowing or speaking, a lump in the neck and unexplained weight loss among the symptoms of mouth cancer, and advises anyone with a lump in the mouth or on the lip to see a GP or dentist. The NHS stresses that these symptoms are very common and can have other causes, but that cancer found early is easier to treat. Another group that can be confused with a torus is cysts growing inside the jawbone and abscesses coming from a tooth; these are told apart from a torus by an examination and an X-ray.

A torus has a particular significance for people who are going to wear a denture or have implants. Cleveland Clinic writes that a torus can make it hard for mouth appliances such as dentures, night guards and braces to fit properly, and that the thin tissue over it can become irritated, particularly in denture wearers. The authors of the Jordanian study also stress that these growths should be taken into account when gum surgery and dentures are being planned. Because a conventional upper complete denture covers the palate, a large palatal torus can make it hard for the denture to sit properly and to hold by suction; a mandibular torus also narrows the space where the tongue-side edge of a lower denture sits.

There are two more interesting findings about tori, and both should be read with caution. The first: in a meta-analysis pooling 11 studies and 1,372 patients, breathing pauses during sleep (obstructive sleep apnoea) were more common in people with a mandibular torus; however, the confidence interval of the calculated risk ratio is wide and crosses the threshold of significance, so this is a hint of an association, not a proven link. If you snore and feel sleepy during the day, mention this to your doctor as well. The second: in some cases the bone of a torus can be used as the patient's own bone in bone grafting operations; in a case report published from Gazi University, bone taken from a mandibular torus was used in a sinus floor lift, and the patient was followed for 2 years without problems. This is a single case; it should not be read as a general method.

The features in the first list are the typical behaviour of a torus or exostosis; these can simply be shown at your next dental check-up and watched. If even a single point from the second list applies, do not wait to book an appointment.

The sequence is built around ruling out the dangerous possibility first. A torus is usually diagnosed by examination alone; if there is doubt, imaging and a tissue sample come in.

1. 1

   Make notes at home: location, side, hardness, time

   Look with a mirror and write down: is the lump on the midline, to one side or symmetrical on both sides; is it as hard as bone or rubbery; is the tissue over it a normal colour; how long have you been aware of it, and is it growing. A photo on your phone and a second one taken a few weeks later turn the question of growth into something concrete.

2. 2

   Examination by a dentist

   Cleveland Clinic writes that a torus is usually recognised at a routine dental examination and that the dentist may take photographs to record its size and position. The dentist presses on the lump to check its hardness, whether it moves and the surrounding tissue, and feels the lymph nodes in the neck.

3. 3

   Imaging if needed

   A test may not be needed to diagnose a torus; Cleveland Clinic notes that a CT scan may be requested to rule out another problem. For cysts or tumours growing from inside the bone, imaging is essential.

4. 4

   A tissue sample when in doubt

   For a hard lump that does not behave like a torus, is growing or has a sore on it, a tissue sample gives the definite diagnosis. MSD writes that with salivary gland tumours, a fine-needle sample confirms the cell type, and CT and MRI show how far it has spread.

5. 5

   Referral according to the source

   For a torus or exostosis, monitoring or surgery depending on the denture plan; for a cyst, oral and maxillofacial surgery; for a suspected salivary gland tumour or mouth cancer, head and neck surgery or ENT.

The torus itself is not dangerous; the options depend on how much it gets in the way of function.

The following are common habits with this complaint that lead to needless worry or to a condition being missed.

The sequence below is for when a torus is removed surgically. Most tori are never removed; a torus that is being monitored has no healing process. The instructions of the surgeon who operates on you come first.

1. The first few days

   Stitches are placed after the procedure, which is done under local anaesthetic. Cleveland Clinic recommends eating soft food, avoiding hard and crunchy food, and taking medicines as instructed.

2. Weeks 1 to 2

   Cleveland Clinic writes that after a mandibular torus is removed, comfort starts to improve noticeably within a week or two. Swelling that lasts longer than a few days is not the usual course.

3. Around week 4

   Cleveland Clinic notes that full healing can take about a month for a palatal torus and up to four weeks for a mandibular torus, and longer for large growths.

4. For a denture or implants

   Impressions for a denture, or planning for implants, are usually done once the area has healed. The timing is decided jointly by the surgeon who operated and the dentist planning the denture.

Most tori need no procedure at all; what widens the scope is whether a procedure is needed and whether the lump really is a torus. These are the items that determine it:

Monitoring or a procedure

A torus that causes no problems is simply checked at examinations; a torus that gets in the way of a denture or speech needs surgery.

Imaging and a tissue sample

For a hard lump that does not behave like a torus, a CT scan, an MRI scan or a biopsy are separate items.

The size and location of the torus

Removing a palatal torus and removing a mandibular torus on both sides are different procedures; with large growths the operation and healing take longer.

The denture plan

Managing a torus through the design of the denture and removing it surgically before making the denture mean a different order of steps and a different scope.