Role of Fluoride in Caries Prevention Flashcards
What fluoride therapy is available in the community?
- School-based brushing and varnish (childsmile)
- Water (some areas)
What fluoride therapy is available/done in clinic?
- Varnishes
- Gels and foams
-Slow release devices (GI etc)
In what setting is there the most fluoride exposure/therapy?
At home
What fluoride therapy can be done at home?
- toothpaste
- mouthrinse
-tablets
What is SDF and when is it good to use?
Silver diamine fluoride
Is good for active carious lesions in primary dentition
How does fluoride prevent caries?
- it promotes remineralisation
- it forms fluoro-apatitie which is less susceptible to demineralisation than hydroxyapatite
Is the topical or systemic effect of Fl- greater?
The topical effect
What might fluoride also have an effect on which does something to acid levels?
May have an effect on bacteria and metabolic pathways resulting in less acid being produced
What is the key to maintaining elevated levels of oral fluoride for as long as possible?
Little amounts often
On what lesions is Fl- most effective?
EARLY lesions
The oral reservoir of Fl- is small. What are the 2 broad types of resevoir?
- Mineral deposits (CaF2 in saliva and fluid phase of plaque)
- Biologically/bacterially bound calcium-fluoride
The aim is to keep F levels in oral fluids at what level?
Cariostatic level
Are fluoride tablets any good?
some studies showed reductions in caries but flawed designs
Topical effect of chewing and swishing around the mouth is what gave any effect
Systemic effect not proven to do anythin
What are the UK guidelines for Fl- tablets?
It is NOT a public health measure
May be applicable to high risk children
Poor risk-benefit balance
Compliance issues
Fluoride mouthwashes see a reduction in caries by around what percent?
30
Is daily or weekly rinsing with Fl- mouthwashes more efective?
daily
Doing what with the Fl- mouthwash is important for the efficacy?
Swishing it around the mouth
What is the P compliance like with the FL- mouthrinses?
generally good compliance
What is the benefit to risk ratio like for Fl- mouthwashes?
good ratio
cost benefit ratio is also low
What is the fl conc in varnish?
22,600 ppm
What kind of contact is there with varnish?
Sustained contact
How does fluoride varnish work?
The colophony resin hardens in contact with saliva to maintain contact of fluoride with the tooth
During the contact there is mobilisation of calcium ions in the enamel and precipitation of calcium fluoride onto the tooth surface
The absorption of fl from the varnish onto tooth surface (enamel and dentine) is what?
rapid
After a single application, the fl content of enamel can increase up to what percent?
70%
The Fl- release from varnish can last how long?
several months
How does calcium fluoride work?
When there is an acid attack the pH falls. Fl- has greater bioavailability when pH is lower so more Fl is released leading to remineralisation
What are acidulated mouthwashes and how do they work?
Low pH mouthwashes.
They stimulate mild demineralisation on tooth surfaces but presence of fluoride from the washes remineralies it.
It is an effective means of getting Fl into teeth (more so than non-acidulated mouth rinses)
Fluoride mousses are useful where? What is the downfall?
In markets with no access to high fluorides (no professionals etc)
There needs to be more evidence regarding them
Describe Fl- release from GI/RMGI.
- slow diffusion
- very small amount but sustained
-possible fl recharge of the GI
Describe how Fl- aids remineralisation of tooth surface.
The Fl- ions absorbed into tooth surface act as nucleators
Ca, P are attracted which drives the formation of new mineral (hydroxyapatite)
What factors determine the anticaries activity of Fl- toothpastes? (4)
- Fl- conc
- Frequency of application
- Rinsing behaviours
- When brushing takes place
For every 500ppm increase of Fl- in toothpastes, what is the reduction in caries percent?
6-7%
The choice of toothpaste for specific patients depends on what?
Careful risk benefit assessment
Describe how the frequency of brushing/application effects the toothpastes anticaries effect?
More frequent brushing results in lower caries increments
Describe how rinsing behaviour affects the fluoride concs in the mouth after brushing. (rinsing with small water volume vs large water volume)
Rinsing with small water vol. removes excess fl in the mouth and a little fl is retained (reservoirs maintained)
Rinsing with large vol. = removal of excess fluoride and reduces the fl in the mouth (rinses out reservoirs as well)
Is rinsing with or without a beaker worse ? (cup vs cupped hands etc)
with a beaker is worse
What are the optimal brushing conditions?
- twice daily
- no rinsing
-1500ppm F paste
Optimal brushing vs sub-optimal brushing led to what % diff in caries incidence?
40-50%
Does the quantity of toothpaste applied correlate with efficacy?
Not really - quantity of toothpaste not strong associated with efficacy
What are the risk of using fluoride?
- inevitable ingestion in young people which can lead to fluorosis
- increased risk of enamel fluorosis
Acute toxicity from ingesting Fl is very rare but in what group is it a potential prob?
In very young children
What is chronic toxicity from Fl?
Developmental defect of enamel (fluorosis)
What is the general consensus about how much fl a young child has to swallow to risk fluorosis?
0.1mg/kg body weight
1mg per day for 1y/o or 2mg/day for 5-6y/o
Although 0.1mg.kg is the general consensus of fl swallowed to risk fluorosis, what is the lower limit?
There is NO LOWER LIMIT below which fluorosis does not occur
NOTE: there seems to be a dose response to severity
The bioavailability of ingested Fl is affected by what?
Stomach contents
i.e. full stomach = lower bioavailability
Describe the impact of an increase in toothpaste conc vs an increase in toothpaste quantity on mg of Fl ingested and therefore increase of fluorosis
increase in conc has less effect than increase in quantitiy
What can we do to maximise caries benefit but reduce fluorosis risk in young children?
- keep toothpaste out of reach
- Brush frequently
- Supervise brushing by young children to reduce risk of swallowing
- use small amount of toothpaste (smear or pea)
- discourage swallowing
- Brush after meals t minimise effect of fluoride ingestion
- encourage spitting out
- avoud excess rinsing (SPIT DONT RINSE)
- Use fl- conc with regards to risk of caries in child
