Hyperdontia is the condition of having supernumerary teeth, or
teeth
A tooth ( : teeth) is a hard, calcified structure found in the jaws (or mouths) of many vertebrates and used to break down food. Some animals, particularly carnivores and omnivores, also use teeth to help with capturing or wounding prey, tear ...
that appear
in addition to the regular number of teeth (32 in the average adult). They can appear in any area of the
dental arch
The dental arches are the two arches (crescent arrangements) of teeth, one on each jaw, that together constitute the dentition. In humans and many other species; the superior (maxillary or upper) dental arch is a little larger than the inferio ...
and can affect any
dental organ. The opposite of hyperdontia is
hypodontia
Hypodontia is defined as the developmental absence of one or more teeth excluding the third molars. It is one of the most common dental anomalies, and can have a negative impact on function, and also appearance. It rarely occurs in primary teet ...
, where there is a congenital lack of teeth, which is a condition seen more commonly than hyperdontia.
[Pathology of the Hard Dental Tissues] The scientific definition of hyperdontia is "any tooth or odontogenic structure that is formed from tooth germ in excess of usual number for any given region of the dental arch."
[R. S. Omer, R. P. Anthonappa, and N. M. King, "Determination of the optimum time for surgical removal of unerupted anterior supernumerary teeth," Pediatric Dentistry, vol. 32, no. 1, pp. 14–20, 2010.] The additional teeth, which may be few or many, can occur on any place in the dental arch. Their arrangement may be symmetrical or non-symmetrical.
Signs and symptoms
The presence of a supernumerary tooth, particularly when seen in young children, is associated with a disturbance of the maxillary incisor region. This commonly results in the impaction of the incisors during the mixed dentition stage. The study debating this also considered many other factors such as: the patient's age, number, morphology, growth orientation and position of the supernumerary tooth. Alongside this issue, the presence of an extra tooth can impede the eruption of adjacent additional or normal teeth. Therefore, the presence of a supernumerary tooth when found must be approached with the appropriate treatment plan, incorporating the likelihood of incisal
crowding
Crowding (or visual crowding) is a perceptual
Perception () is the organization, identification, and interpretation of sensory information in order to represent and understand the presented information or environment. All perception inv ...
.
In some individuals, the additional teeth can erupt far from the dental arch, within the
maxillary sinus
The pyramid-shaped maxillary sinus (or antrum of Highmore) is the largest of the paranasal sinuses, and drains into the middle meatus of the nose through the osteomeatal complex.Human Anatomy, Jacobs, Elsevier, 2008, page 209-210
Structure
It is ...
. The extra teeth may also migrate to a different location after development.
In some cases, supernumerary teeth can lead to the formation of cysts. Crowding is also frequently seen in people with hyperdontia.
Causes
There is evidence of hereditary factors along with some evidence of environmental factors leading to this condition. While a single excess tooth is relatively common, multiple hyperdontia is rare in people with no other associated diseases or syndromes.
Many supernumerary teeth never erupt, but they may delay eruption of nearby teeth or cause other dental or orthodontic problems.
Molar-type extra teeth are the most common type. Dental X-rays are often used to diagnose hyperdontia.
It is suggested that supernumerary teeth develop from a third tooth bud arising from the
dental lamina
The dental lamina is a band of epithelial tissue seen in histologic sections of a developing tooth. The dental lamina is first evidence of tooth development and begins (in humans) at the sixth week in utero or three weeks after the rupture of the ...
near the regular tooth bud or possibly from splitting the regular tooth bud itself. Supernumerary teeth in
deciduous (baby) teeth are less common than in
permanent teeth
Permanent teeth or adult teeth are the second set of teeth formed in diphyodont mammals. In humans and old world simians, there are thirty-two permanent teeth, consisting of six maxillary and six mandibular molars, four maxillary and four mandibul ...
.
Related conditions
Hyperdontia is seen in a number of disorders, including
Gardner's syndrome
Gardner's syndrome (also known as Gardner syndrome, familial polyposis of the colon, or familial colorectal polyposis) is a subtype of familial adenomatous polyposis (FAP). Gardner syndrome is an autosomal dominant form of polyposis characterize ...
and
cleidocranial dysostosis
Cleidocranial dysostosis (CCD), also called cleidocranial dysplasia, is a birth defect that mostly affects the bones and teeth. The collarbones are typically either poorly developed or absent, which allows the shoulders to be brought close togethe ...
, where multiple supernumerary teeth develop.
Other associated conditions are:
Cleidocranial dysplasia
Cleidocranial dysostosis (CCD), also called cleidocranial dysplasia, is a birth defect that mostly affects the bones and teeth. The collarbones are typically either poorly developed or absent, which allows the shoulders to be brought close togethe ...
,
Ehlers–Danlos syndrome Type III,
Ellis–van Creveld syndrome,
Gardner's syndrome
Gardner's syndrome (also known as Gardner syndrome, familial polyposis of the colon, or familial colorectal polyposis) is a subtype of familial adenomatous polyposis (FAP). Gardner syndrome is an autosomal dominant form of polyposis characterize ...
,
Goldenhar syndrome
Goldenhar syndrome is a rare congenital defect characterized by incomplete development of the ear, nose, soft palate, lip and mandible on usually one side of the body. Common clinical manifestations include limbal dermoids, preauricular skin tags ...
,
Hallermann–Streiff syndrome
Hallermann–Streiff syndrome is a congenital disorder that affects growth, cranial development, hair-growth, and dental development. There are fewer than 200 people with the syndrome worldwide. One notable organization that is supporting peopl ...
,
Orofaciodigital syndrome
Orofaciodigital syndrome or oral-facial-digital syndrome is a group of at least 13 related conditions that affect the development of the mouth, facial features, and digits in between 1 in 50,000 to 250,000 newborns with the majority of cases bein ...
type I,
Incontinentia pigmenti
Incontinentia pigmenti (IP) is a rare X-linked dominant genetic disorder that affects the skin, hair, teeth, nails and central nervous system. It is named from its appearance under a microscope.
The disease is characterized by skin abnormalitie ...
,
Marfan syndrome
Marfan syndrome (MFS) is a multi-systemic genetic disorder that affects the connective tissue. Those with the condition tend to be tall and thin, with long arms, legs, fingers, and toes. They also typically have exceptionally flexible joints a ...
,
Nance–Horan syndrome
Nance–Horan syndrome is a rare X-linked dominant syndrome characterized by congenital cataracts leading to profound vision loss, characteristic dysmorphic features, and dental anomalies. Microcornea, microphthalmia, and mild or moderate intel ...
, and
Tricho-rhino-phalangeal syndrome Type 1
Zinc finger transcription factor Trps1 is a protein that in humans is encoded by the ''TRPS1'' gene.
This gene encodes a GATA-like transcription factor that represses GATA-regulated genes and binds to a dynein light chain protein. Binding of the ...
.
Diagnosis
Supernumerary teeth may be detected by taking two different dental
X-ray
An X-ray, or, much less commonly, X-radiation, is a penetrating form of high-energy electromagnetic radiation. Most X-rays have a wavelength ranging from 10 picometers to 10 nanometers, corresponding to frequencies in the range 30&nb ...
s at different angles. Examples of this may be an intra-oral X-ray (one that is taken inside the mouth) and a panoramic radiograph. However, these X-rays are 2D and therefore do not accurately portray the 3D view of the teeth.
Types
![Mesiodens Accessory Teeth](https://upload.wikimedia.org/wikipedia/commons/d/d0/Mesiodens_Accessory_Teeth.jpg)
Supernumerary teeth can be classified by shape and by position. The shapes include the following:
* Supplemental (where the tooth has a normal shape for the teeth in that series);
* Tuberculate (also called ''barrel shaped'');
* Conical (also called ''peg shaped'');
* Compound odontoma (multiple small tooth-like forms);
* Complex odontoma (a disorganized mass of dental tissue)
[Oxford Handbook of Clinical Dentistry]
When classified by position, a supernumerary tooth may be referred to as a ''mesiodens'', a ''paramolar'', or a ''distomolar''.
Occasionally, these teeth do not erupt into the oral cavity but manifest as a
malocclusion
In orthodontics, a malocclusion is a misalignment or incorrect relation between the teeth of the upper and lower dental arches when they approach each other as the jaws close. The English-language term dates from 1864; Edward Angle (1855-1930), ...
.
[Pediatric Gastrointestinal Disease: Pathophysiology, Diagnosis and Management, Volume 1]
The most common supernumerary tooth is a mesiodens, which is a malformed, peg-like tooth that occurs between the
maxillary central incisor
The maxillary central incisor is a human tooth in the front upper jaw, or maxilla, and is usually the most visible of all teeth in the mouth. It is located mesial (closer to the midline of the face) to the maxillary lateral incisor. As with all i ...
s.
Fourth and fifth molars that form behind the third molars are another kind of supernumerary teeth.
Treatment
Although these teeth are usually asymptomatic and pose no threat to the individual, they are often extracted for aesthetic reasons, to allow the eruption of other teeth, orthodontic reasons and/or suspected pathology. This is done particularly if the mesiodens is positioned in the maxillary central incisor region. The traditional method of removal is done by using bone chisels, although a more advanced technique has been found to be more beneficial, especially if surgery is required. Through the use of
piezoelectricity
Piezoelectricity (, ) is the electric charge that accumulates in certain solid materials—such as crystals, certain ceramics, and biological matter such as bone, DNA, and various proteins—in response to applied mechanical stress. The word ''p ...
, piezoelectric ultrasonic bone surgery may be more time-consuming than the traditional method but it seems to reduce the post-operative bleeding and associated complications quite significantly.
Epidemiology
It is evident that hyperdontia is more common in the
permanent dentition
Permanent teeth or adult teeth are the second set of teeth formed in diphyodont mammals. In humans and old world simians, there are thirty-two permanent teeth, consisting of six maxillary and six mandibular molars, four maxillary and four mandibul ...
than in
the primary. There is a considerable difference between males and females in the prevalence of these teeth in permanent dentition; hyperdontia is twice as common in males as in females. However, this approximation varies in terms of location, other associating syndromes that may be present, and the ethnicity of the individual. In terms of ethnicity, it can be seen that hyperdontia is in fact less common in European than in Asian populations.
There is evidence to show that an individual is more likely to have hyperdontia if other members of their family also have the condition.
References
External links
{{Tooth disease
Supernumerary body parts
Developmental tooth pathology
Teeth
Accessory bone