Hypodontia is an inherited condition characterized by the development of missing teeth, regardless of the absent third molar. In cases where there are six or more permanent missing teeth, this condition is called oligodontia. Anodontia refers to a condition in which no teeth are present. Supernumerary teeth refer to a condition in which the tooth is more than ordinary.
The third missing molar occurs in 9-30% of the population studied. In the primary tooth, the maxilla is more affected, with conditions usually involving maxilla lateral incisors.
Many other terms to describe the reduction in the number of teeth appear in the literature: dental aplasia, congenital missing teeth, absence of teeth, tooth agenesis and lack of teeth.
Video Hypodontia
Prevalence
In people of European descent, the most common missing teeth are wisdom teeth (25-35%), permanent upper permanent incisors (2%), lower second premolars (3%), or second upper premolar teeth, with higher prevalence in women than in men. The prevalence of lost primary teeth was found in 0.1-0.9%, with a 1: 1 male and female ratio. Excluding the third molar, permanent tooth loss is 3.5-6.5%. A similar tendency of missing teeth can be seen in about 3-10% of orthodontic patients.
30-50% of people with missing primary teeth will lose permanent teeth as well.
In a systematic review in the Journal Of Orthodontics, the overall prevalence of hypodontia was found to be 6.4%, with the highest incidence in Africa (13.4%). There is an increased risk of hypodontia in women than in men.
Maps Hypodontia
Other dental anomalies associated with Hypodontia
- Conical teeth
- ectopic kaninus
- Cleft lip and palate
- Diastema
- Pending errors
Cause
The cause of missing missing teeth remains unclear, but these conditions are believed to be related to genetic or environmental factors during dental development. Missing teeth have been reported in association with maternal age, low birth weight, multiple births and rubella virus infection during embryonic life.
In a recent study assessing environmental risk factors for hypodontia, it was determined that maternal smoking did play a causal role in hypodontia. Passive smoking and caffeine are also assessed but do not show statistical significance.
There is a possible correlation between tooth agenesis and innervation. Relationships were also postulated between brainstem abnormalities and presence of agenesis.
Hipodontia often occurs in families, and can also be associated with genetic disorders such as ectodermal dysplasia or Down syndrome. Hypodontia can also be seen in people with cleft lip and palate.
Among the possible causes are mentioned genetic, hormonal, environmental and contagious.
Causes due to hormonal defects: idiopathic hypoparathyroid and pseudohypoparathyroidism. It is possible that this defect depends on moniliasis (candidiasis, candida endokrinopati syndrome ).
Environmental causes involving exposure to PCB (ex.dioxin), radiation, anticancer chemotherapy agents, allergy and toxic epidermal necrolysis after the drug.
Causes of hypodontia infection: rubella, candida.
The Journal of the American Dental Association published preliminary data showing statistical linkages between permanent dental hypodontia and epithelial ovarian cancer (EOC). This study shows that women with EOC 8.1 times more likely to experience hypodontia than women without EOC. Therefore, the suggestion is that hypodontia can serve as a "marker" for potential EOC risk in women.
Also increased frequency of hypodontia in twins and low birth weight in twins with hypodontia showed that environmental factors during perinatal were responsible hypodontia.
Genetics
The genetic cause also involves genes MSX1 and PAX9.
The genetic associations for selective dental agenesis ("STHAG") include:
Genetics always plays an important role in dental aplasia. The congenital missing tooth pattern seen in different monozygotic twins, indicates an underlying epigenetic factor, which may be caused by two simultaneous anomalies. This multifactorial etiology involves environmental factors that trigger a genetic anomaly that results in the occurrence of tooth agenesis. Common environmental factors include infection, trauma and drugs that affect this condition. In the case of heredity, evidence of dental germs develops after the surrounding tissue has closed the space required for development may be a contributing factor as well.
Another supported aetiological theory is the way of polygenic inheritance. The combination of epistatic genes and environmental factors influences the phenotypic expression of the genes involved, thus disrupting the early proliferation of dental germs. The isolated cases may be dominant, recessive or even X-linked inherited patterns of inheritance. Mutations in the genes MSX, PAX9 and TGFA are known to cause congenital loss of teeth in some racial groups. MSX1 and MSX2 are important homeobox genes in the mediation of direct mesenteral-epithelial interactions during the growth of craniofacial bone and teeth. MSX1 generally produces second premolar teeth and third molar loss, with a small percentage of first molar teeth. PAX9 and TGFA are involved in regulating between MSX1 and PAX9 which cause hypodontia in the molar.
Research
In the 1960s and 1970s, several studies were conducted sponsored by the US Atomic Energy Commission, with the aim of finding a link between genetics and hypodontia.
Hypodonsia restoration management
Oral rehabilitation of hypodontia, especially where a large number of teeth have not developed, is often a multidisciplinary process, involving orthodontist specialists, consultants in restorative dentistry, and dentists in previous years. The process of treating and managing hypodontia begins in the early years of dental patients where no teeth are identified and the process of maintaining remaining teeth begins. This is mostly done by a pediatric dentist with orthodontic input. After all adult orthodontic eruption teeth are likely to be associated with a restorative dentist regarding optimal dental placement for subsequent replacement by prosthodontic method. This may include the use of resin-retained bridges and implants for composite spaces or resins, veneers or crowns where teeth are small or incorrectly shaped.
References
Source of the article : Wikipedia
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