Fluorosis tooth staining (a complication of excessive fluoride exposure) -
What is fluorosis staining?
Dental fluorosis is a type of permanent tooth staining that results from an elevated systemic exposure to fluoride during the time period when a child's tooth enamel is forming.
The high level of ingested fluoride leads to a disruption in the normal formation of tooth mineral. The result is areas of hypomineralization (under calcification) and increased porosity. (AlShehri 2016) [page references]
What does dental fluorosis look like?
Normal dental enamel has a glass-like translucency. In comparison, areas of a tooth that have been affected by fluorosis will display increased opacity and some type of color variation.
Both of these effects are due to the changes in composition of the tooth's enamel (reduced level of mineralization, increased porosity, increased fluoride content).
There's a direct correlation between the amount of fluoride contained in the tooth's enamel and the severity of the staining, or even damage, the fluorosis has caused. (Hovius 2014)
Types of fluorosis. / Appearance.
Mild dental fluorosis.
The affected white areas are sometimes referred to as "snow capping."
a) Mild and very mild cases.
In the vast majority of cases in the United States, the level of fluorosis that occurs can usually be classified as just "very mild" to "mild."
- Characteristically these cases involve staining that takes the appearance of chalky-white lines, or opaque white patches or flecks, in isolated regions of the tooth's enamel. Any portion of the tooth can be affected.
- When the staining is found right at the tooth's biting edge, it's sometimes referred to as "snow capping" (see picture).
Bilateral symmetry is common.
It's typical for the stain pattern of fluorosis to be at least somewhat bilaterally symmetrical (meaning it has affected the same teeth, and likely even the same tooth locations, on both the left and right side of the person's mouth).
That's because the teeth (left-right matching pairs) and their affected areas were all at the same point in enamel formation when the exposure to the fluoride took place. (See illustration below.)
Severe dental fluorosis.
Note the areas of brown discoloration.
b) Moderate to severe cases.
With higher systemic fluoride exposure, the resulting effects will tend to be more severe.
- Many of these cases will display yellow or brown discolorations. There may also be some degree of tooth surface pitting (porosity).
- It's possible that the fluorosis first presents itself as a whitish area that then due to its low mineral content and porosity picks up brown staining over time.
- In severe cases, the undermineralized enamel may be fragile and therefore become damaged relatively easily (like by events such as chewing, or activities that result in wear or abrasion).
Streaks of fluorosis like these would have all formed during the same general time frame.
They lie at different levels because the teeth were at different stages of development at the time of the exposure.
It's young children who are at risk for fluorosis.
Dental fluorosis only occurs if elevated levels of fluoride are ingested (swallowed) during that time period when a child's tooth enamel is forming.
- That means the most critical years for the risk of fluorosis lie between birth and age 6 or 7.
The damage isn't actually visible until later on.
Because fluorosis staining forms while the teeth are developing (and therefore still lie embedded in the jawbone), it's not visible until the affected teeth have finally come in, which typically occurs between the ages 6 through 12.
Causes of fluorosis staining. / Prevention.
a) The underlying problem.
Small children, especially those younger than age 6, characteristically are not able to reliably spit out when brushing.
As a result they may end up swallowing a large portion of the toothpaste that's been placed on their brush. And if it contains fluoride, over time enough may be ingested that fluorosis forms.
- 1 to 3 year olds may get up to 80% of their daily intake of fluoride from toothpaste. (Almeida 2007)
- It's estimated that 2 to 3 year olds ingest 48% of the amount of toothpaste dispensed, 4 year olds 42%, 5 year olds 34% and 25% in 6 year olds. The estimate for children between 8 and 12 years is around 10%. For adults it's 10% or less. (SCHER 2011).
b) Avoidance / Prevention.
The following suggestions can help to minimize a child's risk for fluorosis.
- Children should be given instructions about how to properly brush and rinse. So to help them avoid swallowing toothpaste, they should be supervised when brushing.
- In most cases it's the amount of product that's used rather than the concentration of its fluoride that poses the greatest risk (Davies 2003). Fluoridated toothpaste should always be dispensed by an adult, not the child.
Read your toothpaste's instructions, generally only a small amount of toothpaste is needed. A common measurement for children is a dab the size of a green pea (0.25 g). For those younger than 3 years, just a smear. Dispensing toothpaste the full length of a child's toothbrush can correlate with an amount that's times (0.75 g) the proper amount.
- As a general rule, unfluoridated tooth cleanser should be used with children 2 years and under. Ask your dentist for their specific recommendation.
- Store fluoridated toothpaste out of the reach of children (some kids like the way it tastes and eat it).
- When purchasing fluoride toothpaste, look for one that has the American Dental Association's (ADA) "Seal of Approval." These products have been shown to be both safe and effective.
Fruit drinks can be the culprit too.
Beyond just toothpaste, bottled juices and juice-flavored drinks manufactured with water may be a source of high levels of fluoride.
These products can have concentrations that are significantly higher than the 0.7 to 1.2 ppm (parts per million) that are considered appropriate and optimal.
Treatment for fluorosis tooth staining.
- With just mild cases of fluorosis, no treatment is required if the person considers the appearance of their teeth acceptable. The integrity of the affected areas of enamel is seldom a concern.
- With moderate or severe cases, especially those where significant surface pitting or dark staining is involved, a repair can be made (filling, veneer or crown placement, depending on the conditions and severity of the case).
Minimally invasive solutions.
In situations where only a relatively minor esthetic improvement is needed, a patient might have several "minimally invasive" options to choose from. They include (use the links provided for further details):
- Teeth whitening treatments - Treatments are used to lighten the overall color of the affected teeth, which helps to mask the appearance of their fluorosis staining. (View an example case that illustrates the use of this technique.)
- Microabrasion - When fluorosis staining is confined to the surface layer of a tooth's enamel, this process can be used to remove it.
- Resin infiltration - This is a relatively new procedure that may offer a minimally invasive solution for mild to moderate fluorosis cases.
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