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Amelogenesis (AI)
OMFP
Question | Answer |
---|---|
What is Amelogenesis Imperfecta (AI)? | A developmental alteration in the structure of enamel in the absence of a systemic disorder. |
What is the main clinical feature of AI? | AI is a group of rare, inherited disorders that are characterized by abnormal enamel formation with a lack of systemic or syndromic findings. |
What is the appearance of AI? | This is a disorder that causes teeth to misshapen with small, discolored, pitted, or grooved enamel, depending on the type of AI. |
What are these teeth prone to? | They are prone to increased wear and potentially loss of tooth structure due to enamel breaking without dysfunctional habits. |
True or False: The varied defects of AI only affect permanent teeth. | False: They affect both primary and permanent dentition. |
What is a sub-type based on? | It is based on the inheritance pattern and clinical features of the disorder. |
What inheritance patterns are possible for this disease? | Autosomal dominant, Autosomal Recessive, and X-linked. |
The type of AI is based on ___: | what aspect of enamel formation is altered. |
What are the names of each of the types in the original classification system? | Type I: Hypoplastic Type II: Hypomaturation Type III: Hypocalcified Type IV: Hypomaturation/Hypoplastic |
What is type I and what is it caused by? | Type I: Hypoplastic This is due to an inadequate deposition of enamel matrix. |
What are some characteristics of Type I? | - Normal enamel mineralization and contrast on x-rays. - Patterns: generalized or localized. - Enamel surface defects: pitted, linear, smooth, rough, agenesis. - Open bite is not rare as there may be no occlusion with the opposing teeth. |
How many subtypes of Type I are there? | 7 |
What is type II and what is it caused by? | Type II: Hypomaturation This is due to normal enamel matrix with defective maturation (crystal structure). |
What are some characteristics of Type II? | - Normal tooth anatomy, but the tooth will have soft and discolored enamel. - Enamel chips from dentin because of the immature nature. - Reduced contrast on x-rays - enamel looks like dentin. - Patterns: Pigmented, X-linked, Snow-capped. |
How many subtypes of Type II are there? | 4 |
What is Type III and what is it caused by? | Type III: Hypocalcified This is due to appropriate matrix laid down, but abnormal or no mineralization. |
What are some characteristics of Type III? | - Normal anatomy, but soft enamel. - Yellow-brown discoloration progresses to black. - Cervical enamel more resistant to this type. - Poor radiographic contract of enamel. - Calculus will build up easily. - Impacted teeth and open bite. |
How many subtypes of Type III are there? | 2 |
What is type IV? | Type IV: Hypomaturation/Hypoplastic |
What are some characteristics of type IV? (Part 1) | - Primary and permanent dentitions affected and this type is severe. - Teeth will exhibit both pigmentations and surface defects. - Poor radiographic contrast. - Displays Taurodontism and large pulp chambers. |
What are some characteristics of type IV? (Part 2) | - Patterns: (A) Hypomaturation/Hypoplastic and (B) Hypoplastic/Hypomaturation - Tricho-dento-osseous syndrome will present with this type. |
How many subtypes of Type IV are there? | 2 |
What is the incidence of AI? | 1/700-14,000 |
How many children does AI affect in the US? | 14,000-16,000 children in the US and 40% have hypocalcified dominant type. |
What are the gender predilections of AI? | The autosomal dominant and recessive forms affect males and females equally. The X-linked dominant type affects twice as many females as males. The X-linked recessive type affects only males. |
How do practitioners go about diagnosis of AI? | Clinical correlation of patient/family history, radiographs, and severity. Dental anomaly decision tree should also be used to rule out syndromes or local factors. Genetic analysis will highlight potential enamel mutation. |
What are the microscopic features of AI? | Histologic samples should have a variable appearance. Due to the quality of the enamel, decalcified specimens do not work in this disorder. Most clinicians use ground sections of the tooth for histological analysis. |
What are treatment options for AI? | There is no treatment to stop enamel dysfunction. Clinicians restore teeth to their normal size and function and can do full restorative coverage to protect the tooth from further decay. Some will require extractions along with prosthesis or implants. |
What is the prognosis of AI? | Overall prognosis is good with restoration of function and will depend on the severity of the disorder. |
What diseases can be provided as differential diagnoses? | - Dentinogenesis Imperfecta - Dental Fluorosis - Tricho-dento-osseous Syndrome - Ectodermal Dysplasia - Multiple syndromes should be considered - Various local disturbances not genetic based |