Гипердонтия: лишние зубы и их особенности

Condition of having extra teeth beyond the regular number of teeth

Hyperdontia is the condition of having supernumerary teeth, or teeth 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 and can affect any dental organ. The opposite of hyperdontia is hypodontia, where there is a congenital lack of teeth, which is a condition seen more commonly than hyperdontia. 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." 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.

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. In some individuals, the additional teeth can erupt far from the dental arch, within the maxillary sinus. The extra teeth may also migrate to a different location after development. 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 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.

Specific genes play a role in determining the number and pattern of teeth that develop in an individual, and mutations or variations in these genes can result in the formation of extra teeth. An individual can inherit a genetic predisposition to hyperdontia from its parents. If an individual with hyperdontia reproduces, their offspring have an increased likelihood of having the same condition, as their offspring have an increased likelihood of having the same condition because hyperdontia has been proposed as having an autosomal dominant mode of inheritance. Furthermore, some developmental syndromes or medical conditions may also result in hyperdontia. For instance, cleidocranial dysplasia (CCD) is a genetic disorder that affects skeletal and dental development and is associated with the presence of supernumerary teeth. Trauma or injury to the oral cavity, particularly during tooth development, also has the potential to trigger the formation of supernumerary teeth because it disrupts normal tooth development. Furthermore, ancestral diets were often tougher and required more extensive chewing, meaning that being in the possession of extra teeth could help to facilitate the consumption of fibrous plant material and raw foods.

Hyperdontia is seen in a number of disorders, including Gardner's syndrome and cleidocranial dysostosis, where multiple supernumerary teeth develop. Other associated conditions are: Cleidocranial dysplasia, Ehlers–Danlos syndrome Type III, Ellis–van Creveld syndrome, Gardner's syndrome, Goldenhar syndrome, Hallermann–Streiff syndrome, Orofaciodigital syndrome type I, Incontinentia pigmenti, Marfan syndrome, Nance–Horan syndrome, and Tricho rhino phalangeal syndrome Type 1.

Supernumerary teeth may be detected by taking two different dental X rays 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. When classified by position, a supernumerary tooth may be referred to as a mesiodens, a paramolar, or a distomolar. The most common supernumerary tooth is a mesiodens, which is a malformed, peg like tooth that occurs between the maxillary central incisors. Fourth and fifth molars that form behind the third molars are another kind of supernumerary teeth.

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, 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.

It is evident that hyperdontia is more common in the permanent dentition 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. but underwent surgery to remove his extraneous teeth. David DeVore Jr. gained internet fame after being filmed after removing a supernumerary tooth at the dentist. Kalpana Balan, an Indian woman entered Guinness World Records for having the most teeth in a human mouth.

A poem by ancient Greek poet Ion describe the hero Heracles as having three rows of teeth. Len Linfhiaclach (lit. "Len of the Many Teeth"), a goldsmith who lived about the year 300, is the subject of Gaelic text Dindseanchas

Tukwishhemish is a character from a Cahuilla folk tale, a beautiful woman who smiled but never laughed on account of her having double rows of teeth in her upper jaw. Witches in certain parts of Estonia are said to be able to be recognized by having unusual teeth including double rows of teeth, giving rise to their being called hambamees (lit. "tooth man"); so as well can the Slavic upyr be recognized by its double rows of teeth.