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In dentistry, anodontia, also called anodontia vera, is a rare genetic disorder characterized by the congenital absence of all primary or permanent teeth. It is divided into 2 subsections, complete absence of teeth or only some absence of teeth. It is associated with the group of skin and nerve syndromes called the ectodermal dysplasias. Anodontia is usually part of a syndrome and seldom occurs as an isolated entity. There is usually no exact cause for anodontia. The defect results in the dental lamina obstruction during embryogenesis due to local, systemic and genetic factors.
Congenital absence of permanent teeth can present as hypodontia, usually missing 1 or 2 permanent teeth, or oligodontia that is the congenital absence of 6 or more teeth. Congenital absence of all wisdom teeth, or third molars, is relatively common. Anodontia is the congenital absence of teeth and can occur in some or all teeth; whereas partial anodontia (or hypodontia), involves two dentitions or only teeth of the permanent dentition (Dorland's 1998). Approximately 1% of the population has oligodontia. Many denominations are attributed to this anomaly: partial anodontia, hypodontia, oligodontia, the congenital absence, anodontia, bilateral aplasia. Anodontia being the term used in controlled vocabulary Medical Subject Headings (MeSH) from MEDLINE which was developed by the United States National Library of Medicine. The congenital absence of at least one permanent tooth is the most common dental anomaly and may contribute to masticator dysfunction, speech impairment, aesthetic problems, and malocclusion (Shapiro and Farrington 1983). Absence of lateral incisors represents a major stereotype. Individuals with this condition are perceived as socially most aggressive compared with people without anodontia (Shaw 1981). The occurrence of anodontia is less so than hypodontia which has a prevalence of 0.1-0.7% in primary teeth and 3-7.5% in permanent teeth.
Hypodontia and anodontia are frequently associated with a multitude of genetic disorders and syndromes, approximately 70. Syndromes particularly involved with ectodermal involvement are a prime circumstance for anodontia to occur, some examples of these are: Rieger's, Robinson's and focal dermal hypoplasia. Three syndromes which classically have signs of anodontia are oculomandibulodyscephaly, mesoectodermal dysplasia and ectodermal dysplasia. In cases of oculomandibulodyscephaly there are no permanent teeth but there are deciduous teeth present. In mesoectodermal dysplasia the symptoms are anodontia and hypodontia. In cases of ectodermal dysplasia oligodontia is also present.
The complications associated with anodontia can vary but the majority results in problems with aesthetic appearance and masticatory function.
Prosthetic replacement of missing teeth is possible using dental implant technology or dentures. This treatment can be successful in giving patients with anodontia a more aesthetically pleasing appearance. The use of an implant prosthesis in the lower jaw could be recommended for younger patients as it is shown to significantly improve the craniofacial growth, social development and self-image. The study associated with this evidence worked with individuals who had ectodermal dysplasia of varying age groups of up to 11, 11 to 18 and more than 18 years. It was noted that the risk of implant failure was significantly higher in patients younger than 18 years, but there is significant reason to use this methodology of treatment in those older. Overall the use of an implant-prosthesis has a considerable functional, aesthetic and psychological advantage when compared to a conventional denture, in the patients.
- Hypodontia, the condition at which the patient has missing teeth
- Hyperdontia, meaning more than the usual number of teeth.
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- Borzabadi-Farahani; A (December 2012). "Orthodontic considerations in restorative management of hypodontia patients with endosseous implants". Journal of Oral Implantology. 38 (6): 779–791. doi:10.1563/AAID-JOI-D-11-00022. PMID 21728818.
- Yap, Alan K. W.; Klineberg, Iven (May–June 2009). "Dental implants in patients with ectodermal dysplasia and tooth agenesis: a critical review of the literature". The International Journal of Prosthodontics. 22 (3): 268–276. ISSN 0893-2174. PMID 19548409.
- de Santé, Haute Autorité (2010). "Traitement implantoprothétique de l'adulte atteint d'agénésies dentaires multiples liées à une maladie rare [Treatment of multiple missing teeth in adults with rare diseases by using implant-supported denture]" (in French). Paris.
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