What is dental fluorosis?
Dental fluorosis is a common disorder, characterized by hypomineralization of tooth enamel caused by ingestion of excessive fluoride during enamel formation.
It appears as a range of visual changes in enamel causing degrees of intrinsic tooth discolouration, and, in some cases, physical damage to the teeth. The severity of dental fluorosis depends on the amount of fluoride exposure, the age of the child, individual response, weight, degree of physical activity, nutrition, and bone growth. Individual susceptibility to fluorosis is also influenced by genetic factors.
What does fluorosis look like?
The “very mild” (and most common) form of fluorosis, is characterized by small, opaque, “paper white” areas scattered irregularly over the tooth, covering less than 25% of the tooth surface. In the “mild” form, these mottled patches can involve up to half of the surface area of the teeth.
When fluorosis is moderate, all of the surfaces of the teeth are mottled and teeth may be ground down and brown stains frequently “disfigure” the teeth.
Severe fluorosis is characterized by brown discoloration and discrete or confluent pitting; brown stains are widespread and teeth often present a corroded-looking appearance.
People with fluorosis are relatively resistant to dental caries (tooth decay caused by bacteria), although there may be cosmetic concern.
Why does fluorosis of teeth happen?
Dental fluorosis is caused by a higher than normal amount of fluoride ingestion whilst teeth are forming. Primary dentin fluorosis and enamel fluorosis can only happen during tooth formation. Chemically, hydroxyapatite is converted to fluorohydroxyapatite.
The most superficial concern in dental fluorosis is aesthetic changes in the permanent dentition (the adult teeth). The period when these teeth are at highest risk of developing fluorosis is between when the child is born up to 6 years old, though there has been some research which proposes that the most crucial course is during the first 2 years of the child’s life. From roughly 7 years old thereafter, most children’s permanent teeth would have undergone complete development (except their wisdom teeth), and therefore their susceptibility to fluorosis is greatly reduced, or even insignificant, despite the amount of intake of fluoride.
What are the sources of fluoride?
Many well-known sources of fluoride may contribute to overexposure including dentifrice/fluoridated mouthrinse (which young children may swallow), excessive ingestion of fluoride toothpaste, bottled waters which are not tested for their fluoride content, inappropriate use of fluoride supplements, ingestion of foods rich in fluoride and public water fluoridation. Public water fluoridation is directly or indirectly responsible for 40% of all fluorosis, but the resulting effect due to water fluoridation is largely and typically aesthetic. Severe cases can be caused by exposure to water that is naturally fluoridated to levels above the recommended levels, or by exposure to other fluoride sources such as brick tea or pollution from high fluoride coal.
How can we prevent fluorosis?
Dental fluorosis can be prevented at a population level through defluoridation. It is the downward adjustment of the level of fluoride in drinking water. However, there are other sources of fluoride such as fluoride containing toothpastes. Also, defluoridation of water will not reverse the condiiton in an individual once exposure to excessive levels of fluoride during the years of tooth enamel formation has already occurred.
What are the treatment options in fluorosis?
Dental fluorosis may or may not be of cosmetic concern. In some cases, when there is a varying degree of negative psychosocial effect, the treatment options are:
- Mild cases:Tooth bleaching
- Moderate cases:Micro-abrasion (outer affected layer of enamel is abraded in an acidic environment)
- Severe cases:Composite fillings, Micro-abrasion, Veneers, Crowns