Amelogenesis imperfecta is a group of rare genetic conditions in which the outer layer of the teeth (enamel) fails to develop properly. People with amelogenesis imperfecta will have small, yellow, or brown teeth that are very prone to damage and breakage.
The exact incidence of amelogenesis imperfecta isn’t known, but it’s estimated to occur in just 1 out of every 14,000 people in the United States.
Amelogenesis imperfecta is caused by mutations in the genes AMELX, ENAM, or MMP20. These genes are responsible for making the proteins needed for normal formation of enamel. Enamel is the hard, mineral-rich material that forms the protective outer layer of your teeth. A mutation in any one of these genes can prevent it from making the correct protein, leading to enamel that is thin or soft.
The mutated genes can be passed on from parents to their children, or the mutation can develop in people with no family history of the disease.
The main symptom of amelogenesis imperfecta is defective enamel. This occurs in both baby teeth and adult permanent teeth. In general, symptoms include:
- smaller-than-normal teeth
- yellow or brown discoloration of the teeth
- teeth that are prone to damage and breakage
- sensitive teeth
- open bite malocclusion, a misalignment in which the upper and lower teeth don’t make contact with each other when the mouth is closed
The exact characteristics of the enamel depends on the type of amelogenesis imperfecta:
Type I: Hypoplastic
In this form, there is a defect in the amount of enamel created. In other words, the enamel is hard, but there isn’t enough of it. The teeth are small and may be white, yellow, or brown, and the enamel is quite thin. The teeth also have pits and grooves.
Type I represents the majority of all cases of amelogenesis imperfecta.
Type II: Hypomaturation
Hypomaturation means there is a defect in the final growth and maturation of enamel. The teeth are a creamy opaque to yellow or brown with sensitivity. The enamel has a normal thickness, but it’s too soft, so the teeth appear mottled and may wear away and break.
Hypomaturation represents between 20 to 40 percent of all cases of amelogenesis imperfecta.
Type III: Hypocalcified
In this type, a defect occurs in the initial stages of enamel formation. The enamel may have a normal thickness, but it’s too soft. The teeth may be white, yellow, or brown, and the enamel may be rough. The teeth may also be extremely sensitive to hot and cold.
This is the least common type of amelogenesis imperfecta, representing about 7 percent of all cases.
Amelogenesis imperfecta vs. dentinogenesis imperfecta
Amelogenesis imperfecta and dentinogenesis imperfecta are both genetic disorders of tooth development.
Dentinogenesis imperfecta affects a different part of the tooth, the dentin. This is a bone-like substance that makes up the middle layer of your teeth. Dentinogenesis imperfecta is caused by mutations in the DSPP gene. People with dentinogenesis imperfecta have teeth that are translucent and blue-grey or yellow-brown in color.
In both conditions, the teeth are weak and prone to breakage.
Amelogenesis imperfecta is typically diagnosed by a dentist. They will take a family history and perform an oral exam to assess the enamel. Your dentist will take X-rays both inside and outside your mouth, but usually the diagnosis can be made by visual examination.
A radiographic exam can help your dentist see contrast between the enamel and dentin of your teeth. This type of exam aids them in assessing the density of your tooth enamel. Knowing the density can help your dentist determine which type of treatment you need.
Without effective enamel, your teeth are prone to damage and breakage, as well as gum disease (gingivitis or periodontitis) and tooth decay. People with the condition will have to practice stringent oral hygiene. They will need to visit their dentist more frequently for a cleaning and evaluation. Most will need extensive dental treatment, which often poses a significant financial burden for the person or their family.
In addition, because the condition affects the way teeth look, some people may experience emotional or social issues, including depression and low self-esteem. Teenagers in particular may become withdrawn due to the pressure to fit in among their peers.
At the moment, there is no standard treatment for amelogenesis imperfecta. Treatment depends on the type and severity of the condition. Your dentist will have to also take into consideration your age, the overall condition of your teeth, and the treatments you can afford.
Some examples of treatment options include:
In tooth bonding, high-density, modern plastics called composite resins or porcelain veneers are attached to teeth to fill in gaps. Bonding procedures are often used for people with hypoplastic amelogenesis imperfecta because their teeth are usually hard enough to hold on to the bond.
Full crown restoration
A crown is a tooth-shaped cap that is placed over an existing tooth. It helps restore that tooth’s shape and size.
In the hypocalcified and hypomaturation types, the enamel is usually too weak to hold on to bonded restorations. So crowns are one of the most durable and predictable options for restoring these teeth. Crowns can also help prevent or eliminate tooth decay.
Temporary crowns of gold, porcelain, or stainless steel can be created for children or adolescents with the condition. Permanent crowns are often delayed by dentists until early adulthood, when all the teeth are present and stable.
People with amelogenesis often need orthodontic treatment, such as braces or appliances. The goal isn’t necessarily to make the teeth perfectly straight, but rather to get the teeth in a better position for restorations.
Good dental hygiene
Before any restorative treatment can be done, it’s important to have optimal dental health. Bleeding or inflamed gums (gingivitis) makes placement of bonded restorations extremely difficult. Excellent oral hygiene at home is crucial.
If you have painful sensitivity to heat and cold, you can use a desensitizing toothpaste.
Visiting a dentist on a regular schedule to have a professional cleaning is also very important.
Similar to good dental hygiene, diets that are low in sugar can help prevent cavities and gum disease, promoting healthy teeth.
Dentures or overlay dentures
A denture is a removable artificial device. It’s designed to look like real teeth. An overdenture or an overlay denture is a type of denture that lies directly on your existing teeth. Overlay dentures are reversible and relatively inexpensive compared to other treatment options. They can be a temporary or even permanent treatment option for people with a limited budget.
If tooth decay has already progressed too far, the teeth may have to be extracted. Traditional dentures may then be necessary to replace the missing teeth.
The earlier the treatment, the better the outlook. Proper dental care can help protect teeth from further damage. If left untreated, the teeth and enamel may break. This damage can be painful and will affect the overall appearance of the teeth.
With treatment, however, the teeth can look normal and remain functional for life. If you’re a parent who thinks your child’s tooth enamel hasn’t developed properly, see your dentist.