Lecture 4 - Fluoride & Caries Flashcards
Enamel is laid down by…
ameloblasts
During the _________ stage, the ameloblasts lay down the protein matrix for the rod crystal structure and the rods begin to form.
secretory
During the __________ maturation stage, the ameloblasts fill in the crystal structure with mineral.
pre-eruptive
Very high physiologic levels of fluoride during the secretory stage can cause _______ and this condition is called _______.
pitting
fluorosis
Chronically, moderately high levels of fluoride during the _________ maturation stage causes disruptions in crystal formation (chalky whiteness and weakness of enamel). This is very common.
pre-eruptive
T/F
There is no benefit from fluoridated water before tooth eruption.
True
Fluoridation must continue _________ ____ in order to continue its benefits.
throughout life
The effects of water fluoridation are ________.
topical
Fluorosis risk is _________ by ingestion.
increased
________ supplementation still officially recommended for high risk children.
Systemic
Enamel composition is __% mineral (HA), __% water, and _% organic matrix.
87
11
2
Newly formed crystals in a young tooth usually contain what 3 impurities?
carbonate
sodium
other ions
In what process is the HA crystal perfected in a tooth when bathed in saliva (Ca++ and PO4) and exposed to fluoride?
post-eruptive enamel maturation
In post-eruptive enamel formation, phosphate replaces ________, calcium replaces ________, and fluoride replaces _________. These replacements make HA less soluble (stronger).
carbonate
sodium
hydroxyl
T/F
Young teeth are more susceptible to caries because post-eruptive maturation strengthens them over time.
True
HA dissolves if pH drops below ___.
5.5
What prevents the dissolving of calcium ions?
Fluoride ions
T/F
Fluorhydroyxapatite (FHA) is less soluble than HA making enamel stronger.
True
T/F
Lactic acid causes dissolution of enamel mineral that diffuses to the surface where reaction with fluoride causes formation of FHA.
True
T/F
Fluoride diffuses well into the body of a lesion.
False
Fluoride does NOT diffuse well into the body of a lesion, because it reacts before it gets there with the outer layers to form FHA
Subsurface HA is _______ while FHA is ______ in the surface layers.
dissolved
formed
Whitespot lesions can have very high fluoride concentrations on their surface because of _____-_____ cycles.
demin-remin
T/F
Areas covered by plaque have higher fluoride levels.
True
T/F Worn areas (abrasion, erosion) contain low levels of fluoride.
True
What 4 things increase CaF2 deposition?
- increasing concentration of fluoride
- increasing exposure time
- lowering pH
- protecting- limit rinsing or cover with varnish
Saliva is supersaturated with what two molecules which prevent teeth from dissolving?
calcium
phosphate
T/F
Fluorosis can occur during any stage of life.
False
Fluorosis can only occur when teeth are developing
T/F
Fluoride levels are dependent on daily intake and bone stores.
True
There are no homeostatic mechanisms to control F concentration anywhere in the body
T/F
Mild fluorosis is perceived as attractive by most people because the increase in enamel porosity appears chalky white.
True
Which teeth are at the greatest risk of fluorosis and during what age range?
Upper central incisors
15-30 months old
T/F
Bacteria do NOT develop resistance to fluoride.
True
What are the different methods of fluoride delivery?
- community-based water fluoridation
- self-applied
- professionally applied
What are the three things on which the surface concentration of fluoride depends?
- topical exposure to F
- acid exposure
- wear
If fluorosis is severe, enamel may be _______.
fragile
Self-applied method of fluoride delivery has ____ frequency and ___ concentration.
high
low
Professionally applied methods of fluoride delivery has ___ frequency and ____ concentration.
low
high
When fluoride concentration is >100 ppm, what is deposited on tooth surface?
CaF2
What amount of ppm of fluoride is safe and typically the amount found in OTC toothpaste?
1000 ppm
Prescription toothpaste is available at what ppm?
5000 ppm
T/F
There is no relationship between the fluoride concentration and caries benefit.
False
The higher the fluoride concentration, the better the toothpaste, but too much can lead to fluorosis
T/F
There is no relationship between the amount of toothpaste and caries benefit.
True
It’s not how much you use, but how much fluoride is present
Fluoride supplements (ingesting fluoride) are really only recommended for ____ _____ patients.
high risk
not supported by evidence
What is the typical concentration of fluoride in an OTC fluoride rinse?
0.02% (200 ppm)
T/F
OTC rinses have shown to be as effective as toothpaste because you don’t rinse.
True
What two types of professional products are most often used due to comfort to the patient?
Foams and varnishes
