Brief overview
- Definition: Hyperdontia stands for an excess of teeth, hypodontia for an undercount of teeth.
- Treatment: Hyperdontia is treated surgically (in children in general, in adults only in case of discomfort). In hypodontia, bridges, implants, braces or surgery (exposing retained teeth, i.e. teeth held back in the jaw) help.
- Causes: Hyperdontia is genetically predisposed. True hypodontia is also hereditary and is also associated with various diseases (such as cleft lip and palate) or the chromosomal disorder Down syndrome. Acquired hypodontia can be the result of an accident, for example.
- Diagnosis: Imaging procedures such as X-rays. In the case of hyperdontia, a larger gap between the incisors may also indicate impacted teeth.
What is hyperdontia?
Hyperdontia is a dental anomaly: supernumerary teeth are present in the dentition. Specifically, experts speak of hyperdontia when there are more than 20 milk teeth in a child or more than 32 permanent teeth in an adult. The excess teeth are in the way of the regular teeth and can lead to malocclusions of the dentition.
Different forms of hyperdontia can be distinguished:
- Paramolar: Here there are additional teeth, also usually cone-shaped, between the first and second or second and third large molars (molars), and usually in the upper jaw. The supernumerary teeth may fuse with the roots of the molars.
- Distomolar: The extra teeth here are located behind the third major molars. They are often fused with their roots.
- Multiple hyperdontia / Cleidocranial dysplasia: The technical terms are used by experts when many (multiple) plants of supernumerary teeth are found in the jaw.
What is meant by hypodontia?
True hypodontia is when teeth are missing from birth. In hypodontia in children, there are fewer than 20 deciduous teeth. Affected adults have fewer than 32 teeth.
The congenital absence of teeth can have a significant impact on child development: The jawbone does not grow properly because the pressure stimulus in the area of the tooth gap is missing during chewing. In addition, speech and chewing may be impaired.
Missing teeth most frequently affect the wisdom teeth, and less frequently, for example, the front molars or the lateral incisors. In about half of those affected, more than one tooth is missing.
Experts distinguish between several forms of missing teeth:
- Hypodontia: Single or few teeth are missing.
- Anodontia: There are no teeth at all in the jaw. However, the frequency of this hypodontia variant is very low, i.e.: anodontia is extremely rare.
Doctors speak of acquired hypodontia when teeth have fallen out, for example after an accident or in the course of a disease.
How is hyperdontia treated?
The supernumerary teeth are in the way of the regular teeth and can lead to malocclusions of the dentition. Especially in children, hyperdontia must therefore usually be treated surgically. In this case, an oral surgeon removes the excess teeth or tooth attachments.
In adults, the extra teeth can remain in place as long as there is no discomfort associated with them. Sometimes, however, they are a nuisance, for example for aesthetic reasons in the case of significant malocclusions. In this case, it is advisable to have the hyperdontia treated by surgery even in adulthood.
How is hypodontia treated?
There are various methods of treatment for missing teeth. Often the teeth are in place but cannot erupt, for example, because they are obstructed by other teeth. In this case, oral surgery can help to expose the impacted (retained) teeth.
The treatment of hypodontia always belongs in the hands of an experienced orthodontist. In a holistic therapy plan, the individual jaw and tooth situation of the affected person is taken into account.
What are the causes of hyperdontia?
The cause of hyperdontia is probably the division of a tooth germ (embryonic tooth attachment in the jaw), which later results in two teeth. Why this happens is not clear. Experts suspect a genetically determined overactivity of the tooth ridge during the tooth formation phase.
What are the causes of hypodontia?
Hypodontia is mostly based on heredity: the undercount of teeth has genetic causes and occurs in families. In addition, it is increasingly observed in certain diseases or chromosomal disorders. These include, for example:
- Cleft lip and palate: In this congenital malformation, the upper lip is not fused or the palate is split and directly connected to the nose.
- Hemolytic anemia: In this particular form of anemia, the lifespan of the red blood cells (erythrocytes) is significantly shortened.
- Down syndrome (trisomy 21): This chromosomal disorder leads to more or less pronounced intellectual and physical impairments.
- Bloch-Sulzberger syndrome: This very rare hereditary disease leads mainly to changes in the skin, teeth, nails and hair.
How to recognize hypo- and hyperdontia?
The absence of teeth (hypodontia) can be detected on an X-ray.
Imaging procedures are also necessary for the diagnosis of hyperdontia: Since in the vast majority of cases the supernumerary teeth are not erupted but hidden (retained), they can only be detected with imaging procedures such as X-rays. However, a visible indication of hyperdontia can be a wide gap between the incisors. This may give rise to further examination with imaging techniques.
