Dental fluorosis

**Dental fluorosis** is a change in the hard outer layer of the teeth (the **enamel**). It happens when a child takes in too much fluoride while teeth are still forming. This can make the enamel look different. The color may change. In strong cases, the enamel can be weaker than normal.

In very mild cases, there are small white spots that cover less than one quarter of the tooth. In mild cases, the white areas can cover up to half of the tooth. In moderate cases, all surfaces are affected. Brown stains may show. In severe cases, the enamel may have many pits. Teeth can look brown and rough.

People with fluorosis often get fewer cavities than others. But the color changes can cause worry about appearance. In moderate to severe cases, teeth can be weaker and may wear down more easily.

## Diagnosis

Dentists usually diagnose fluorosis by looking at clean, dry teeth with good light. The look of fluorosis can change from person to person. It depends on how long, how much, and when the child took in fluoride. Mild fluorosis often shows as small, white, cloudy areas without clear borders. With more severe fluorosis, the enamel under the surface becomes more porous (less mineral). Yellow or brown stains can appear. Pits may also appear in strong cases.

Other tooth problems can look like fluorosis. These include:
- Turner's hypoplasia (often in one area)
- Enamel changes from untreated celiac disease
- Some mild forms of amelogenesis imperfecta and enamel hypoplasia
- Enamel defects after infection or trauma in the baby tooth
- Tooth decay (sometimes confused with fluorosis)

## Classification

Dentists use simple scales to record how strong fluorosis is.

### Dean's index

The dentist gives a score from 0 to 5. The score is based on the most affected two or more teeth.
|Class|Code|Short description|
| --- | --- | --- |
|Normal|0|Enamel looks normal. Smooth and shiny.|
|Questionable|1|A few white flecks or small spots.|
|Very mild|2|Small white spots cover less than 25% of tooth.|
|Mild|3|White areas cover up to half of tooth.|
|Moderate|4|All surfaces affected. Wear and brown stains common.|
|Severe|5|All surfaces affected with many pits. Tooth shape may change. Brown stains are widespread.|

### TF index

The Thylstrup–Fejerskov index (TF index) gives a score from 0 to 9. It helps describe mild to very severe changes in more detail.

## Causes

Fluorosis happens only while teeth are forming in childhood. The risk is highest from birth to about 6 years old. It may be most important in the first two years of life. After about age 7, most permanent teeth (except wisdom teeth) have finished forming, so the risk becomes very low.

Too much fluoride can come from many places. Examples include swallowing toothpaste, using too much mouth rinse, taking fluoride tablets when not needed, some foods and drinks, and public water fluoridation.
Very high natural fluoride in well water, some brick teas, or smoke from coal with high fluoride can also cause severe fluorosis.

Genes may affect who gets fluorosis more easily than others.

## How it happens

Scientists think fluoride changes how enamel forms. It may affect the cells that make enamel (ameloblasts). It may also change the way certain proteins and minerals are broken down or removed. The result is enamel with less mineral. This enamel looks more opaque and can be brittle in strong cases.

## Management

Dental fluorosis may or may not be a cosmetic concern. In some cases, there can be social or personal worry. Treatment choices include:
- Mild cases: Tooth bleaching
- Moderate cases: Enamel microabrasion (removes a thin outer layer)
- Severe cases: Composite fillings, micro-abrasion, veneers, or crowns

## Epidemiology

Fluorosis is common in the United States. One report found 41% of adolescents with definite fluorosis and another 20% with “questionable” signs. Later surveys also showed increases compared with the 1980s and 1990s.

## Prevention

To prevent fluorosis, keep total fluoride intake low during early childhood. Examples:
- Use only a small smear or pea-sized amount of fluoride toothpaste for young children, and help them spit it out.
- Follow local advice about water fluoride levels.
- Ask a dentist or pediatrician before using supplements in fluoridated areas.
Public health groups say water fluoridation is safe and helps prevent tooth decay, but too much fluoride in early childhood can cause mild fluorosis.

## History

Writers in ancient times may have described teeth like fluorosis. In 1901, a U.S. dentist, Frederick McKay, reported “Colorado brown stain.” Later work showed the cause was fluoride in drinking water during childhood. H. Trendley Dean studied the problem and made a simple scale (_Dean’s Index_) that is still used today. Over time, scientists also found that the right amount of fluoride helps prevent tooth decay.

## Infobox (medical condition)

- **name**: Dental fluorosis
- **synonyms**: Mottled enamel
- **image**: Dental fluorosis (mild).png
- **caption**: Mild dental fluorosis shows small white patches on the enamel
- **field**: Dentistry