What is Dental Fluorosis?

“You’ve got what?!?  Dental fluorosis?  That sounds serious.  I hope it’s not catching.”

 Fluorosis is a dental condition that occurs during the years that a tooth is developing.  Excess fluoride is absorbed through the gut and can be stored in bones and teeth.  It is noted clinically as white striations but can appear brown that may be attributed to dietary staining of the effected enamel.  Severe fluorosis can present as pitted enamel.  Microscopically, the enamel layer is more porous and thus, weaker in nature. 

The age that fluorosis occurs is during the time the permanent teeth are forming, but it is not seen clinically until the teeth erupt into the mouth.  The top front four teeth are where fluorosis is the most commonly visible.  These teeth are affectionately called the central and lateral incisors.  The incisors begin forming early in a child’s first year of life and the visible portion of the tooth (crown) completes forming when the child is 4-5 years old.  Teeth begin forming at the bottom edge and form upwards until the root has been completed.  As you can see in the picture above, the staining occurs in lines.  The fluorosis is seen in the tooth layer that was forming at the time the child received excess fluoride. 

For example, in the picture above, the central incisors have a brown line near the top third of the tooth.  The lateral incisors have brown staining in the bottom third of the tooth.  It is likely that the fluorosis occurred at the same time, but the centrals and the laterals were at different stages of crown development.

Fluorosis is more common in the southwestern United States due to its higher naturally occurring fluoride levels.  Typically, fluorosis occurs from a long-term ingestion of excess fluoride and is not noticeable if a child has an acute fluoride toxicity event from eating a tube of toothpaste.  One instance that can cause fluorosis is using fluoridated water to mix infant formula.  Since this is the basis of the infant’s diet, especially early on, fluorosis can occur if fluoridated water is used on a regular basis. 

How do we treat a tooth with dental fluorosis?  Back in the day, the only treatment options were to use a high-speed handpiece to remove the stained tooth structure and place a filling or a crown.  I’ve said it before and I’ll say it again, I love the day and age we live in because we have more conservative options at our disposal.  I will list the options from most conservative to most aggressive:

  1. Tooth whitening – no tooth structure will be removed, but the discolored tooth may blend with whitening treatments.  Follow up treatment is usually required.
  2. Resin infiltration: a treatment option where the enamel is opened with an acid to release staining, apply a bleaching agent to the tooth, and apply a sealant to protect the tooth and prevent future staining.
  3. Microabrasion: the top layer of the enamel is removed with an abrasive to reveal a more esthetic layer of the tooth (not always an option for fluorosis, due to it affecting the entire depth of enamel)
  4. Remove the stained portion with a dental handpiece and apply a filling
  5. Remove tooth structure to allow for an esthetic crown to be placed

To summarize, causes of fluorosis can be atributed to long-term fluoride ingestion such as, drinking fluoridated water at levels higher than recommended by the CDC or using fluoridated water to mix infant formula.  Fluoride varnish is the most commonly placed dental fluoride at cleaning appointments.  Research studies do not support a correlation between increased dental fluorosis and fluoride varnish application.

References:

Dental fluorosis:

https://pdfs.semanticscholar.org/0fb5/28d4b7a7e193e90bd533b5ea54f816b04375.pdf

Dental Tooth Formation Chart:

https://www.aapd.org/globalassets/media/policies_guidelines/r_dentalgrowth.pdf

Correlation of fluorosis and fluoride varnish placement:

https://www.aapd.org/assets/1/7/Fluoride_varnish.pdf

American Academy of Pediatric Dentistry Fluoride Guidelines:

https://www.aapd.org/media/Policies_Guidelines/P_FluorideUse.pdf