Fluoride Flashcards
What pH does enamel start to demineralise
5.5
What pH does dentine start to demineralise
6.5
What is enamel mainly comprised of
Hydroxyapatite 96%
What are the 2 ions which enamel is composed of
Phosphate ions
Calcium ions
What is the primary mineral source of fluorine
Fluorite/fluorapatite/cryolite
List 5 systemic intake of fluoride sources
Toothpaste
Water supplies
Mouthwash
Food made with fluoridated water
Fluoride supplements
At what level does fluorosis not occur
Under 1.0 ppm
What did Dr F McKay find in 1909
That a large amount of children had brown stains on their teeth which appeared to be resistant to dental caries
What was discovered in 1945 in relation to fluoride
By adding fluoride to the water supply it reduced dental caries by 50-60% and was safe
List 3 reasons for what fluoride does to help prevent dental caries
It enhances remineralisation of tooth enamel
Inhibits demineralisation of tooth enamel
Makes cariogenic bacteria less able to produce acid from carbohydrates
Why did topical application occur
As water fluoridation found that anterior teeth had greater reduction to caries than posterior teeth since the water came into contact with the anteriors more than posterior teeth
What happens in the presence of fluoride during tooth development
The OH- ion is replaced by the fluoride ion producing fluorapatite
What is more resistant to acid demineralisation
Fluorapatite compared to hydroxyapatite
In the presence of fluoride what also happens to tooth development
They have more well coalesced grooves on the occlusal surfaces and fewer pits and fissures
How does demineralisation occur
When sucrose turns into acid which isolates hydroxyapatite
Naturally occurring bacteria on the surface of teeth form biofilm creating plaque
Bacteria then convert sugar into acid causing pH levels to fall
Hydroxyapatite begins to dissolve removing the inorganic component of enamel
How does fluoride help prevent demineralisation
When it is present in saliva F- binds to remineralising surface of enamel
Induces the preferential formation of fluorapatite in place of hydroxyapatite
How does fluoride help remineralisation
The fluoride ion replaces the OH- groups in hydroxyapatite to make fluorapatite
Rebuilds the surface of teeth
Saliva is constantly buffering even when sugar is present it just takes longer
pH remains low for a time after the main sugar attack
When is fluoride more readily absorbed
By demineralised enamel than sound enamel
What does fluoride in plaque inhibit
Glycolysis in cariogenic bacteria
After brushing or using mouthwash how long does it take for the fluoride content in the mouth to return back to normal
After 1-2 hours
Why does fluorosis occur
Due to excess fluoride during tooth development as it interacts with mineralising tissues causing alterations
