fluoride Flashcards
how does fluoride make the enamel apatite less soluble?
becomes incorporated as fluoroapatie = less sol
displaces carbon and magnesium ions = improves crystalline structure and reduces solubility
how does F have an effect on enamel remineralisation after acid attack?
reduced the more soluble carbonate of enamel = less sol
releases F ions after acid attack from enamel into saliva = favours remineralisation
accumulates in early carious lesions at concs high enough to reduce solubility
how does fluoride affect the morphology of teeth when ingested during tooth development?
wider fissures
more rounded cusps
enamel and dentine thinner
F is an enzyme inhibitor and has an effect on plaque metabolism how?
binding to plaque bacteria at high concentrations
inhibiting metabolic pathways so demineralising acids are not formed
F absorbed where?
stored where?
excreted from where?
what is a partial barrier to F?
stomach
skeletal tissue
via kidneys/sweat/faeces
placenta
dosage of F tablets/drops?
0,25 mg - 6m-3yrs
0.5mg - 3-6yrs
1mg - over 6 yrs
what effects can F have on skeletal tissue? over 8 ppm regular intake
skeletal fluorosis - increase in bone density and increased thickness of long bones
calcification of ligaments
what is fluorosis?
excess fluoride causing distrurbance of enamel matrix and calcification and impaired ameloblastic function
child under 3 years what ppmF toothpaste?
no less than 1000
at what ages should parental supervision whilst brushing cease?
7
what did Dr Frederick McKay find in 1901?
colorado mottling stain - fluoridated water
what is the issue with carbonated portions of HA?
weak struture
suscpetible to acid erosion
what is the conc of daily F mw?
0.05%
what is the conc of weekly F mw?
0.2%
what is the critical pH of Fluoroapatite?
4.5 = larger drop in pH needed to cause disolution
what did Dr Trendley Dean do in 1934?
21 cities
high f in water = less caries
what is the Strathclyde case?
1978 - catherine mccoll - lord jauncey
claims fluoridated water was against informed consent
on what 4 grounds was F in water banned?
beyond powers
nuisance
breach of water act
medicinal product with no lisence
what did the 1980 Knox report conclude?
Fluoride at 1ppm not mutagenic but theraputic
for what age is duraphat 2800 recommended for?
10 and over
for what age is duraphat 5000 recommended for?
over 16’s
what happened in oregan state hospital?
fluoride given instead of powdered milk
236 died
47 injured
how should F tablets be given?
sucked in sulcus to give topical and systemic effects
how much does 1g of 1500ppmF toothpaste have of fluoride?
1.5mg
what is the adult toxic fluoride dose?
5-10g
what is the child toxic fluoride dose?
over 5g
what bulk sweetner has synergistic effects with fluoride?
xylitol
how to work out if child at risk of F toxicity?
body weight x 5g = x
how much toothpaste have they consumed?
from birth to 6 months how should a child look after their teeth?
soft tb
smear of tp
1000ppmF
how should a toddler brush their teeth?
smear and soft tb
1000-1500ppmF
what is the conc of duraphat varnish?
22600ppmF
children (under 7) giving concern - high risk/disabled - should be given what advice e.g cleaning/F?
pea size 1350-1500ppmF, fluoride varnish applied 3-4 times a year, tablets and drops
