What is an Exostosis & Torus?
These are bony swellings that develop in the mouth.
These are not that unusual. They come in a number of
shapes, sizes and positions (that is, either in the midline of
the roof of the mouth, the tongue side of the lower jaw or
the cheek side of both upper and lower jaws).
These bony swellings are given the ‘technical’ names of
exostoses or tori.
The torus is considered to be a developmental anomaly,
although it does not present until adult life and often will
continue to grow slowly throughout life.
|Photos of bony swellings in the roof of the mouth (palate),
The Torus Palatinus commonly forms towards the back of
the hard palate (roof of mouth) in the midline. The swelling
is rounded and symmetrical, sometimes with a midline
groove. It is not usually noticed until middle age and, if it
interferes with the fitting of a denture, it can be removed.
Most palatal tori are less than 2 cm in diameter but their
size can change throughout life.
The prevalence of palatal tori ranges from 9% - 60% of the
population and are more common than bony growths
occurring on the mandible (lower jaw), known as torus
mandibularis (ranges from 5% - 40%).
The prevalence rate for tori is 27 / 1,000 adults. These
bony lumps are not present until the late teen and early
adult years and many, if not most, continue to slowly
enlarge over time. Fewer than 3% occur in children.
Taken as a group, these bony lumps are found in at least
3% of adults and are more common in females than in
|Photos of bony swellings in the floor of the mouth,
Superficial bony masses / lumps found in another site (of
the mouth or body) are typically given the catch-all name of
exostosis or osteoma. They are considered to be trauma-
provoked inflammatory responses or true (benign)
neoplasms. Unless such a bony prominence is specifically
located, is stalked or is associated with an osteoma-
producing syndrome such as the Gardner syndrome, there
may be no means by which to differentiate an exostosis
from an osteoma, even under the microscope.
What are the signs & symptoms of an exostosis & torus?
Tori can be categorised by their appearance.
- Arising as a broad base and a smooth surface, flat tori
are located on the midline of the palate and extend
symmetrically to either side.
- Spindle tori have a ridge located at their midline.
- Nodular tori have multiple bony growths that each
have their own base.
- Lobular tori have multiple bony growths with a
The torus may be bosselated or multi-lobulated but the
exostosis is typically a single, broad-based, smooth-
surfaced mass, perhaps with a central sharp, pointed
projection of bone producing tenderness immediately
beneath the surface mucosa.
Slowly enlarging, recurrent lesions occasionally are seen,
but there is no malignant transformation potential. The
patient should be evaluated for Gardner syndrome should
there be multiple bony growths or lesions not in the classic
torus or buccal exostosis locations. Intestinal polyposis
and cutaneous cysts or fibromas are other common
features of this autosomal dominant syndrome.
What are the causes of an exostosis & torus?
Tori / buccal exostoses may be the outcome of mild,
chronic peri-osteal ischæmia secondary to mild nasal
septum pressures (palatal torus) or the torquing action of
the arch of the mandible (mandibular torus) or lateral
pressures from the roots of the underlying teeth (buccal
exostosis) but this is largely speculation.
The most similar bony growth outside the jaws is the
bunion of the lateral foot.
They are more common in early adult life and are
associated with bruxism (tooth grinding).
The size of the tori may fluctuate throughout life and in
some cases the tori can be large enough to touch each
other in the midline of mouth. Consequently, it is believed
that mandibular tori are the result of local stresses and not
solely on genetic influences.
How are they treated?
Neither the torus nor the exostosis requires treatment
unless it becomes so large that:
• it interferes with function or denture placement
• suffers from recurring traumatic surface ulceration
(usually from sharp foods, such as potato chips or fish
• contributing to a periodontal condition
If removal of the tori is needed, surgery can be done to
reduce the amount of bone, but the tori may reform in
cases where nearby teeth still receive local stresses.
When treatment is elected, the tori may be chiseled off of
the jaw or removed via bone-burr cutting / smoothing
through the base of the bony lump.
J Cont Dent Practice 2006. Torus Palatinus and Torus
Mandibularis in Edentulous Patients
Bond's Book of Oral Diseases (4th Edition) / The
Maxillofacial Center for Diagnostics & Research
jaw, in the region of the premolars / bicuspids (and above
the location of the mylohyoid muscle's attachment to the
mandible). They are typically (90% of cases ) bilateral (i.e
on both sides) forming hard, rounded swellings. The
management is the same as that of the same as that of the
A buccal exostosis is the formation of an exostosis (bone
mass) on the outer, cheek-facing side of the maxilla (upper
jaw) just above the teeth or the cheek-facing side of the
mandible (lower jaw). They are less common on the lower
jaw. They begin to develop in early adulthood and may
very slowly enlarge over years. They are painless and
self-limiting but may contribute to periodontal disease (gum
disease / pyorrhoea) if they become too large. They can
be removed with surgery. Buccal exostoses have no
|Last Updated 20th July 2011