Find information on thousands of medical conditions and prescription drugs.

Amelogenesis imperfecta

Amelogenesis imperfecta (AI) is a disorder of tooth development. This condition causes teeth to be unusually small, discolored, pitted or grooved, and prone to rapid wear and breakage. Other dental abnormalities are also possible, and the defects vary among affected individuals. These problems can affect both primary (baby) teeth and permanent teeth. more...

Home
Diseases
A
Aagenaes syndrome
Aarskog Ose Pande syndrome
Aarskog syndrome
Aase Smith syndrome
Aase syndrome
ABCD syndrome
Abdallat Davis Farrage...
Abdominal aortic aneurysm
Abdominal cystic...
Abdominal defects
Ablutophobia
Absence of Gluteal muscle
Acalvaria
Acanthocheilonemiasis
Acanthocytosis
Acarophobia
Acatalasemia
Accessory pancreas
Achalasia
Achard syndrome
Achard-Thiers syndrome
Acheiropodia
Achondrogenesis
Achondrogenesis type 1A
Achondrogenesis type 1B
Achondroplasia
Achondroplastic dwarfism
Achromatopsia
Acid maltase deficiency
Ackerman syndrome
Acne
Acne rosacea
Acoustic neuroma
Acquired ichthyosis
Acquired syphilis
Acrofacial dysostosis,...
Acromegaly
Acrophobia
Acrospiroma
Actinomycosis
Activated protein C...
Acute febrile...
Acute intermittent porphyria
Acute lymphoblastic leukemia
Acute lymphocytic leukemia
Acute mountain sickness
Acute myelocytic leukemia
Acute myelogenous leukemia
Acute necrotizing...
Acute promyelocytic leukemia
Acute renal failure
Acute respiratory...
Acute tubular necrosis
Adams Nance syndrome
Adams-Oliver syndrome
Addison's disease
Adducted thumb syndrome...
Adenoid cystic carcinoma
Adenoma
Adenomyosis
Adenosine deaminase...
Adenosine monophosphate...
Adie syndrome
Adrenal incidentaloma
Adrenal insufficiency
Adrenocortical carcinoma
Adrenogenital syndrome
Adrenoleukodystrophy
Aerophobia
Agoraphobia
Agrizoophobia
Agyrophobia
Aicardi syndrome
Aichmophobia
AIDS
AIDS Dementia Complex
Ainhum
Albinism
Albright's hereditary...
Albuminurophobia
Alcaptonuria
Alcohol fetopathy
Alcoholic hepatitis
Alcoholic liver cirrhosis
Alektorophobia
Alexander disease
Alien hand syndrome
Alkaptonuria
Alliumphobia
Alopecia
Alopecia areata
Alopecia totalis
Alopecia universalis
Alpers disease
Alpha 1-antitrypsin...
Alpha-mannosidosis
Alport syndrome
Alternating hemiplegia
Alzheimer's disease
Amaurosis
Amblyopia
Ambras syndrome
Amelogenesis imperfecta
Amenorrhea
American trypanosomiasis
Amoebiasis
Amyloidosis
Amyotrophic lateral...
Anaphylaxis
Androgen insensitivity...
Anemia
Anemia, Diamond-Blackfan
Anemia, Pernicious
Anemia, Sideroblastic
Anemophobia
Anencephaly
Aneurysm
Aneurysm
Aneurysm of sinus of...
Angelman syndrome
Anguillulosis
Aniridia
Anisakiasis
Ankylosing spondylitis
Ankylostomiasis
Annular pancreas
Anorchidism
Anorexia nervosa
Anosmia
Anotia
Anthophobia
Anthrax disease
Antiphospholipid syndrome
Antisocial personality...
Antithrombin deficiency,...
Anton's syndrome
Aortic aneurysm
Aortic coarctation
Aortic dissection
Aortic valve stenosis
Apert syndrome
Aphthous stomatitis
Apiphobia
Aplastic anemia
Appendicitis
Apraxia
Arachnoiditis
Argininosuccinate...
Argininosuccinic aciduria
Argyria
Arnold-Chiari malformation
Arrhythmogenic right...
Arteriovenous malformation
Arteritis
Arthritis
Arthritis, Juvenile
Arthrogryposis
Arthrogryposis multiplex...
Asbestosis
Ascariasis
Aseptic meningitis
Asherman's syndrome
Aspartylglycosaminuria
Aspergillosis
Asphyxia neonatorum
Asthenia
Asthenia
Asthenophobia
Asthma
Astrocytoma
Ataxia telangiectasia
Atelectasis
Atelosteogenesis, type II
Atherosclerosis
Athetosis
Atopic Dermatitis
Atrial septal defect
Atrioventricular septal...
Atrophy
Attention Deficit...
Autoimmune hepatitis
Autoimmune...
Automysophobia
Autonomic dysfunction
Familial Alzheimer disease
Senescence
B
C
D
E
F
G
H
I
J
K
L
M
N
O
P
Q
R
S
T
U
V
W
X
Y
Z
Medicines

It is a genetic disorder because the instructions to form the proteins for the enamel are encoded in the genes and are passed from generation to generation. New mutations are also possible.

Researchers have described at least 14 forms of amelogenesis imperfecta. These types are distinguished by their specific dental abnormalities and by their pattern of inheritance.

Features

Amelogenesis imperfecta presents with abnormal formation of the enamel or external layer of teeth. Enamel is composed mostly of mineral, that is formed and regulated by the proteins in it. AI is due to the malfunction of the proteins in the enamel: ameloblastin, enamelin, tuftelin and amelogenin.

People afflicted with amelogenesis imperfecta have teeth with abnormal colour: yellow, brown or grey. The teeth have a higher risk for cavities and are hypersensitive to temperature changes. This disorder can afflict any number of teeth.

Genetics

Up to date, mutations in the AMELX, ENAM MMP20and KLK-4 genes have been found to cause amelogenesis imperfecta (non-syndromic form). The AMELX, ENAM, KLK-4 and MMP20 genes provide instructions for making proteins that are essential for normal tooth development. These proteins are involved in the formation of enamel, which is a hard, calcium-rich material that forms the protective outer layer of each tooth. Mutations in any of these genes alter the structure of these proteins or prevent the genes from making any protein at all. As a result, tooth enamel is abnormally thin or soft and may have a yellow or brown color. Teeth with defective enamel are weak and easily damaged.

Researchers are looking for mutations in other genes that may also cause amelogenesis imperfecta.

Amelogenesis imperfecta can have different inheritance patterns depending on the gene that is altered. Most cases are caused by mutations in the ENAM gene and are inherited in an autosomal dominant pattern. This type of inheritance means one copy of the altered gene in each cell is sufficient to cause the disorder.

Amelogenesis imperfecta is also inherited in an autosomal recessive pattern; this form of the disorder can result from mutations in the ENAM or MMP20 gene. Autosomal recessive inheritance means two copies of the gene in each cell are altered.

About 5% of amelogenesis imperfecta cases are caused by mutations in the AMELX gene and are inherited in an X-linked pattern. A condition is considered X-linked if the mutated gene that causes the disorder is located on the X chromosome, one of the two sex chromosomes. In most cases, males with an X-linked form of this condition experience more severe dental abnormalities than affected females.

Read more at Wikipedia.org


[List your site here Free!]


Dental anomalies
From Encyclopedia of Nursing and Allied Health, by RDA Cindy F. Ovard

Definition

Dental anomalies are craniofacial abnormalities of form, function, or position of the teeth, bones, and tissues of the jaw and mouth.

Description

Dental anomalies can range from missing or stained teeth to cleft palates. Many are expressions of other, more complex disorders. The National Institute of Dental and Craniofacial Research (NIDCR) estimates that in the United States a baby is born every hour with a craniofacial defect.

Causes and symptoms

Many dental anomalies are caused by inherited genetic defects or result from spontaneous genetic mutations. The Center for Biotechnology Information recognizes 1,250 gene loci for craniofacial diseases and disorders. Dental deformities may also have environmental, traumatic, or nutritional causes; these may develop or become clinically apparent at any time during an individual's life.

Genetic defects

The most common genetic craniofacial deformity is clefting of the lip and/or palate, a defect estimated by the NIDCR to occur once in every 500 births. A family history of clefting increases the chances of inheriting the disorder. Seen more often in boys than in girls, cleft lip is usually unilateral, appearing three times more frequently on the left side than on the right. Less common is a bilateral cleft, a condition formerly known as "harelip." An incomplete cleft stops short of the nostril; a complete cleft extends into the nostril. Both types frequently involve the palate as well. The typical patient with cleft palate and cleft ridge exhibits large defects in the roof of the palate with a direct opening into the nasal cavity.

Dentinogenesis imperfecta type II (DGI-II), another genetic defect, causes severely discolored teeth that break easily. Amelogenesis imperfecta produces only a soft, thin layer of tooth enamel. This lets the dentin show through, making teeth look yellow, and leaves them weak, easily damaged, and susceptible to decay.

Other genetic anomalies are less debilitating. Malocclusion, meaning bad or misaligned bite, is caused by crowding teeth, extra teeth, missing teeth, or jaws that are out of alignment. Most malocclusions are inherited genetically, although some can be caused by accidents, early or late loss of baby teeth, or prolonged thumb sucking. Orthodontia usually corrects this problem.

Relative microdontia is an inherited condition that produces smaller-than-normal teeth, usually in the upper jaw. To correct this condition crowns or veneers are applied to make the teeth the same size as the others. Microdontia is neither painful nor harmful; treatment is intended to improve the patient's bite and appearance.

Partial anodontia, or congenitally missing teeth, is a condition in which one or more permanent teeth fail to appear, although primary (baby) teeth usually erupt. Third molars are absent in as many as 35 percent of all subjects examined. Maxillary lateral incisors and maxillary and mandibular second premolars (bicuspids) also frequently fail to appear. When this happens, many dentists choose to leave the primary tooth in place to prevent the malocclusion that might otherwise occur. If this is not feasible, a dentist may extract the tooth and close the space with braces or cover it with a bridge.

Idiopathic anomalies

Stafne's bone cavity, also called static bone cyst or lingual mandibular bone concavity, is an anomaly of unknown etiology. A painless condition, it is an indentation of the jawbone that may contain muscle or salivary tissue. The skin covering this area is soft to the touch and feels concave. No treatment is required, although biopsies are often performed to rule out the presence of a malignant tumor.

Condylar hyperplasia, another idiopathic anomaly, affects the temporomandibular joint and surrounding tissues. The condition is characterized by unrestrained growth of the condyle, which deforms the face, jaw, and bite. Surgery is usually required to restore order, although once growth has stopped orthodontics are often helpful. Condylar hypoplasia occurs when one condyle is markedly shorter than the other, a condition that also causes facial and dental deformities. Surgery can restore balance, and orthodontics are indicated as well.

Environmental causes

Environmental anomalies are caused by external agents, including diet, that affect the teeth and gums. Extended use of the antibiotic tetracycline in young children, for example, can cause dark brown discoloration of the teeth. Fluorosis, an overabundance of fluorine in the diet, can create white or mottled spots on the teeth. This is most commonly seen in children who ingest greater-than-recommended amounts of fluoride by swallowing large quantities of fluoridated toothpaste. Teeth naturally darken with age, as the enamel thins and the dentin shows through. Coffee, tea, and red wine can also stain the teeth. Even children who swim an average of six hours or more a week in a pool may develop brown stains on their teeth.

Bulimia can cause severe decalcification of the teeth. Acid from constant regurgitation eats away at the enamel, especially in the molar region. This weakens the teeth, making them both susceptible to decay and highly sensitive. Unless the bulimia is arrested, sensitivity increases until the nerve is exposed and root canal therapy is needed or extraction is required.

Poor nutrition can also cause dental anomalies. Scurvy, a disease caused by a lack of vitamin C, affects periodontal and other connective tissue, causing purple, swollen, bleeding gums and, if untreated, tooth loss. Anemia, caused by a lack of iron in the diet, causes fiery red gum tissues. Both of these anomalies can be corrected with proper nutrition and routine care.

Other anomalies

Concrescence is the fusion of teeth above and below the gum line, although each tooth has separate roots. The teeth are united by cementum only. It may be caused by crowding or injury. Most commonly it occurs with the second premolars (bicuspids). This is a painless anomaly and treatment is required only for cosmetic reasons.

Supernumerary teeth are extra permanent teeth that may or may not erupt and can be found anywhere in the mouth. The most common is the mesiodens, a small tooth with a cone-shaped crown and a short root situated between the maxillary central incisors. Heredity may play a role in the development of supernumerary teeth, but other factors are thought to contribute as well. Supernumerary teeth can be extracted with no harm to the patient.

Diagnosis

Dental anomalies can be evidence of systemic disease and may have more than one cause. After weighing the patient's symptoms, pain (if any), health risks, family history, aesthetic considerations, treatment costs, and insurance coverage, the dentist will decide whether to treat or simply monitor the condition.

Treatment

Treatment is intended to eliminate or diminish the defect, manage pain, and alleviate the patient's concerns. Treatment may progress in multiple phases, including a program of continuing care that allows the dentist or doctor to evaluate the treatment's effectiveness.

In most cases, surgery can correct the deformity. Cleft lips are usually repaired before the infant is a month or two old, with excellent cosmetic and functional results. Surgical repair of a cleft palate, however, is not usually performed until the patient is approximately eighteen months old, to minimize the risk of damaging important growth centers. Psychological services are often included as part of the treatment along with speech and hearing services.

Depending on the severity of the anomaly, treatment can be expensive, but medical and dental insurance can help limit out-of-pocket expenses for the patient. Sometimes treatment will be covered by medical insurance if procedures are performed by an oral surgeon or medical doctor instead of a dentist.

Prognosis

Although many orofacial anomalies are currently managed, rather than treated, the rapid advance of science-such as the ability to identify mutated genes-promise future cures and treatments that will eliminate or reduce the number of defects currently seen. Gene therapy may also someday be applied to the treatment of many craniofacial anomalies, both to repair congenital defects and to accelerate healing after trauma. Gene mapping may also help doctors know which patients are susceptible to what type of anomalies.

The NIDCR is the primary sponsor of craniofacial research and training in the United States. The institute supports a variety of projects, including basic studies of cell migration and differentiation, cell signaling, patterns of gene expression, growth factor effects, tooth formation and eruption, and bone formation. These studies explore the genetic and molecular mechanisms behind craniofacial abnormalities and are intended to prevent or correct the anomaly or improve the patient's ability to function with it.

Health care team roles

No one specialist can provide the range of treatment that is frequently needed for many dental anomalies. The most effective management is accomplished with a team of professionals who can render a comprehensive diagnosis, determine treatment needs and priorities, and supervise long-term planning. A list of physicians and specialists required to treat a craniofacial deformity might include: plastic surgeon, otolaryngologist (ear, nose, and throat specialist), audiologist, speech-language pathologist, oral/maxillofacial surgeon, orthodontist, pediatric/family dentist, dental hygienist, prosthodontist, and geneticist or genetic counselor.

Prevention

The ADA advises dentists to discourage patients from using tobacco and illicit drugs, and to emphasize sound nutrition to maintain oral health and prevent nutritional anomalies. The NIDCR encourages clinical studies to diagnose genetic anomalies, decrease environmental risks, and improve treatment. Genetic counseling, mapping, and testing can help prevent dental anomalies in the next generation of children.

Key Terms

Anomaly
A deformity or abnormality.

Bridge
A dental prosthesis covering an open space in the mouth.

Cementum
A bony substance that covers the root of the tooth.

Condyle
The uppermost end of the mandible that sits in the zygomatic arch and allows the jaw to move.

Congenital
Present at birth; a nonhereditary condition acquired in utero.

Crown
1. The natural part of the tooth covered by enamel. 2. A restorative, protective shell that fits over a diseased or malformed tooth.

Decalcification
The wearing away of the enamel on the teeth.

Etiology
Cause or origin.

Extraction
Removal of the tooth.

Genetic
Inherited from the parents.

Mandible
Jaw, especially the lower jawbone.

Maxillary
Relating to the upper jaw region.

Maxillary central incisors
The front teeth on the upper jaw.

Maxillary lateral incisors
The teeth on the right and left quadrants of the upper jaw next to the front centrals.

Root canal therapy
Removal of the pulp of a tooth.

Veneer
A thin porcelain overlay that covers only the anterior surface of a tooth.

Return to Amelogenesis imperfecta
Home Contact Resources Exchange Links ebay