Exostosis Mouth – A Benign Bony Growth in the Jaw

Our mouth is a small part of our body. However, it consists of a variety of components that work together to help us eat, drink, swallow and speak.

Sometimes, you may notice unfamiliar structures in your mouth that may worry you. An exostosis is one of those structures.


Exostosis mouth refers to bony outgrowths of calcified bones in the oral cavity. Exostosis may develop on the maxilla or the mandible.

The term exostosis may sound scary, but there is nothing to worry about. Exostosis is a rare, benign oral condition which often doesn’t require any treatment.

Commonly these overgrowths cause no harm to the oral health and go unnoticed for several years.

Research studies have shown that exostosis in the mouth is detected by chance. Often these anomalies are present in the form of tori on both the upper and lower jaw. Treatment is not required unless it affects the functions of the mouth.

This article covers the details of the development of exostosis, its causes, clinical symptoms and some of the necessary treatment options.

What is exostosis?

Exostosis, also known as Tori, are bony outgrowths that develop in the mouth. Although it is a rare condition, the presence of exostosis is not that unusual.

Exostosis primarily can occur in various shapes, sizes and locations. For example, it is commonly found in the midline of the palate or the lingual surface of the lower jaw below the premolars. (1)

Exostosis is considered as a developmental anomaly which usually starts to develop after puberty and continues to grow slowly throughout life.

These bony growths exist for years before an individual notice them. Exostosis is a benign condition and poses no threat to the health of the person.

What causes exostosis?

The exact cause of exostosis is still unknown. However, there are specific factors that may contribute to this abnormal bony overgrowth –

  • Palatal exostosis may develop as a result of chronic periosteal ischemia secondary to mild nasal septum pressure
  • Mandibular exostosis may form due to torquing action of the mandibular arch
  • Buccal exostosis may develop as a result of lateral forces from the roots of the underlying teeth

These factors are mere speculation. The definite cause is yet to be found. Mandibular exostosis is also believed to develop due to local stress and genetic influence.

What are the types of exostosis?

Exostosis can be widely divided into three types –

Torus Palatinus

Torus palatinus is a bony overgrowth that develops on the hard palate in the midline. Usually, the growth is round and symmetrical with a midline groove. Often, palatal tori are 2 cm in diameter and are not noticed until middle age.

Prevalence of palatal tori may range from 9-60% among the population. Generally, palatal tori start to develop in late teen or early adult years.

Palatal tori are more common in occurrence than mandibular tori.

Torus Mandibularis

Torus mandibularis is a type of exostosis which commonly develops on the lingual side of the lower jaw below the premolars. 90% of these exostoses develop bilaterally. Bony growth is usually round and firm. (2)

Prevalence of mandibular tori is around 5-40%, and they occur less frequently as compared to palatal tori. Mandibular torus is more commonly found in females.

Buccal Exostosis

Buccal exostosis as the name suggests forms on the outer surface of the maxilla or mandible, facing the cheek. Like other exostoses, buccal outgrowths are benign and have no malignant potential. It develops during early adulthood and continues to grow throughout life. (3)

Buccal exostosis is more commonly found on the maxilla. They are often painless and self-limiting. However, enlarged growths may cause periodontal problems.

What are the clinical signs and symptoms?

Exostosis often goes unnoticed until they cause a problem in the mouth or are detected accidentally. Typical signs and symptoms of exostosis may include –  (4)

  • A single bony overgrowth with a broad base and smooth outer surface. Usually, palatal tori are flat and extend symmetrically on either side of the midline.
  • Sometimes, exostosis may have a pointed central projection which often makes the underlying mucosal layer tender.
  • Individual variations of exostosis may include spindle tori which has a ridge in the midline, nodular tori where every nodule has its base and lobular tori which is characterized by multiple growths on a single base.

How does exostosis affect oral health?

Generally, exostosis does not cause any problem unless they enlarge in size and interfere with the functions of the mouth. For example, large exostosis may interfere while speaking. Some may cause a problem in patients who wear dentures.

Exostosis with bony projections usually has a thin mucosal layer which can easily get injured by sharp food causing ulcerations on that site.

Large buccal exostosis may sometimes cause harm to the periodontal health of the teeth around it.

How can exostosis be treated?

Treatment of exostosis is required only when there are the following problems –

  • It interferes with the functions of the mouth.
  • Interference with denture placement
  • Recurrent traumatic surface ulcerations
  • Periodontal compromise

In such cases, an oral surgeon can remove the growth under local anesthesia. Commonly the bony growth is removed with a high-speed dental, and the tissues are sutured back.

Dental lasers have recently gained popularity in treating exostosis. Lasers can penetrate hard tissue and provide better results. They are a less invasive and more effective option as compared to conventional methods.

Take away message

Exostosis may develop in different locations in the mouth. They may also vary in shape and size. Exostosis commonly develops after puberty around late teens or early adulthood.


Exostosis is painless overgrowths which often go unnoticed in the mouth. Regular dental check-ups may help to detect such conditions of the mouth.

While exostosis may seem alarming, they are usually not a topic of concern. Exostosis is a benign condition and does not carry any malignant potentials.

If you notice any bony outgrowths in your mouth, consult your dentist and take advise from them. Treatment of exostosis is usually not required until it affects your oral tissues or functions of the mouth.


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