In this blog, we’re going to look at how Fluoride works…its mechanism of action.
Fluoride ions from different sources (i.e. toothpaste, varnishes and gels), act by re-mineralizing enamel and forming Fluorapatite.
A cavity starts because acids are produced by bacteria in the mouth that break down any fermentable carbohydrate that is present (see blog ‘The Cavity Process’ posted on October 28, 2012). The enamel becomes demineralized.
Fluoride acts to decrease the rate of demineralization and in fact increases the rate of re-mineralization. It’s the balance between the frequency of the damaging acid attack and the reparative fluoride exposure that determines whether a cavity will progress.
Routes of Entry of Fluoride
1. Systemic: This is mainly for children, because their adult teeth are still developing in their jaws.
• Via routine drinking water, drops, salt, tablets
• Most cities have fluoride in their drinking water, so they don’t have to take it in any other form (ie: those listed above)
2. Topically: This benefits both adults and children.
• Can be in the form of a toothpaste, gel, rinse or varnish
• It works while in direct contact with your teeth
In the image above, a child is being given a fluoride treatment in a disposable tray.
As mentioned in the previous blog, topical fluoride acts by preventing a new cavity from progressing.
Fluoride: Its Effects on Exposed Root Surfaces
Fluoride also acts to prevent root decay in cases where the roots of the teeth are exposed, i.e. recession.
Remember, the roots of the teeth are made up of dentin which is much softer than the enamel. If the roots of the teeth are exposed to plaque and food debris then they will decay quite readily. Fluoride acts to delay or prevent this.
Root Recession and Dry mouth: A Recipe for Decay
Dry mouth occurs when the salivary flow decreases. This happens often when taking certain medication or undergoing radiation therapy to the head and neck area.
We recommend those who have recession and dry mouth (due to medication, radiation or any other cause), to apply fluoride to these root surfaces on a regular basis, to prevent them from decaying.
In the next blog, we’ll look at the different situations in which Fluoride is indicated.
Written by Dr. Robert Axlerad…your friendly neighbourhood dentist.