The role of fluoride in caries prevention

Question 1

what are the diff ways to target the population

Answer 1

population
community level
individual level

Question 2

What are the fluoride therapy settings

Answer 2

community
in clinic
at home

Question 3

What fluoride therapy can be done in the community

Answer 3

○ Water
		○ School based brushing (childsmile)
		○ Varnish
		○ Salt
		○ Milk
		○ Tablets
		○ Rinsing 
In clinic

Question 4

What fluoride therapy can be done in clinic

Answer 4

○ Varnish
○ Gels and foams
○ Slow release
SDF (newly come in with covid)

Question 5

What fluoride therapy can be done at home

Answer 5

○ Toothpaste
○ Mouthrinse
○ Tablets

Question 6

How does fluoride prevent caries

Answer 6

• Fluoride present in fluid at the plaque/tooth interface promotes remineralisation
  
  • Fluoro-apatite formed is less susceptible to demineralisation
  • Topical effect is greater than systemic
  • Fluoride may also have an effect on bacteria and metabolic pathways resulting in less acid being produced
  • Maintain elevated oral levels of fluoride for as long as possible (little and often)
  • Fluoride is the most effective on early lesions

Question 7

Describe the oral reservoir for fluoride

Answer 7

• The oral reservoir is small
• Fluoride from toothbrushing disappears quickly
• Oral reservoirs consist of 2 main types
○ Mineral deposits (Calcium fluoride:fluoroapatite)
§ Calcium fluoride is found in saliva and fluid phase of plaque
○ Biologically/bacterially bound calcium fluoride

Question 8

What is the aim for fluoride in the oral reservoir

Answer 8

• The aim is to maintain cariostatic levels of fluoride in oral fluids so that is the key goal for manufacturers of dental products

Question 9

What is more effective, topical or systemic

Answer 9

• Generally agreed that main effect is topical and this is important with caries
  
  • Water fluoridation is effective as universal and passive
  • Dentifrice use should be encouraged and should be optimised through simple advice and education
  • Public health vs. personal interventions

Question 10

What is the method of delivering fluoride in oral care products

Answer 10

• Toothpaste
• Mouth rinses
• Varnishes and gels
Tablets

Question 11

What is water fluoridation

Answer 11

• This is when the community water supply is adjusted so the fluoride content is 0.8-1.0ppm (natural water also contains fluoride)
○ 1ppm reduces the caries risk and has minimal fluorosis risk
• Occurs in some areas in England
• Despite fluoride being more effective topically, water fluoridation is still relevant as when water is ingested, the fluoride is incorporated into saliva meaning saliva will contain more frequent amounts of saliva

Question 12

What are fluoride tablets

Answer 12

• Clinical trails showed reductions in caries increments but studies were flawed in design
• The best outcomes result from
○ Chewing, swishing of the tablet prior to swallowing
○ Teeth are already erupted
• Not a public health measure
• It may be applicable to high risk children

Question 13

What is the dosage for fluoride tablets

Answer 13

• The dosage is
○ 6 months to 3 years = 0.25mg
○ 3-6 years = 0.5mg
○ >6 years = 1 mgF

Question 14

When are fluoride tablets used

Answer 14

• Systemic method of delivery
• Poor risk benefit balance
• Can be useful for compliance issues with more vulnerable children
Generally from a dental public health perspective and a efficacy and safety perspective it is not recommended

Question 15

What are fluoride mouth rinses available as

Answer 15

• Commonly available for home use as
○ Daily - low concentration of 0.05%
Weekly - higher concentration of 0.2%

Question 16

What fluoride mouth rinse is more effective

Answer 16

daily but more expensive

Question 17

What has to be done for fluoride mouth rinse to increase efficacy

Answer 17

swishing around the mouth

Question 18

What is fluoride varnish

Answer 18

• Fluoride varnish is a means of delivering high volume concentration of sodium fluoride to the tooth surface
The varnish is able to set and get a sustained contact that aids in efficacy against caries prevention
high fluoride conc

Question 19

Who can fluoride varnish be applied by

Answer 19

dentists

DCP

Question 20

How does fluoride varnish work

Answer 20

○ Colophony resin hardens in contact with saliva to maintain contact of fluoride with the tooth
○ This allows mobilisation of calcium ions into the enamel surface of the tooth and a precipitation of calcium fluoride onto the tooth surface
These deposits of calcium fluoride can release fluoride into the oral environment over a period of time

Question 21

What is the kinetics of fluoride adsorption

Answer 21

• Rapid absorption on tooth surface (enamel and dentine)
• Increase in fluoride content of enamel up to 77% after a single application
Progressive release of fluoride over several months

Question 22

How does calcium fluoride work

Answer 22

• During acid attack pH falls
• Fluoride products have greater bioavailability at a lower pH
As the pH lowers, fluoride ions are released into the oral environment and these help help remineralisation

Question 23

What are acidulated mouth rinses

Answer 23

• Low pH
• Stimulate mild demineralisation on tooth surfaces
• Presence of fluoride aids remineralisation and also the low pH increases the bioavailibility of fluoride
Effective way of getting fluoride into the tooth more so than non acidulated rinses

Question 24

What are fluoride boosters

Answer 24

• Casein phosphopeptide - amorphous calcium phosphate (CPP-ACP)
• Not suitable for milk allergies
• Used to be adjunct to fluoride but now supplied with fluoride
• Can be used at home or in office trays
• Useful in markets with no access to high fluorides
Systematic reviews indicate more research needed

Question 25

Describe fluoride release from GI /RMGI

Answer 25

○ ‘early washout’ - 4 weeks from surface layer (early release)
○ Slower diffusion through bulk cement
○ Actual amount is very small but sustained which is the goal of fluoride delivery
○ Evidence says that glass ionomer can be recharged with fluoride but still unsure
The evidence of clinical benefit still is not that much

Question 26

What is the effect of fluoride at the tooth surface

Answer 26

• The presence of fluoride during caries alters the demineralisation/remineralisation dynamic
  
  • Partially demineralised crystals act as nucleators
  • Fluoride ions are adsorbed to the crystal surface
  • They attract calcium and phosphate so a new mineral is formed

Question 27

What do the principal mechanism of fluoride in caries control rely upon the presence of

Answer 27

○ Fluoride in saliva
○ Fluoride at plaque fluid and tooth interface
Fluoride in fluids around lesion mineral crystals

Question 28

What is the effect of fluoride at the tooth surface optimized by

Answer 28

○ Delivery of fluoride to tooth surface, plaque and plaque fluid
§ Remember the size of the oral reservoir and ‘fluoride boosting’
Maintaining fluoride levels (frequency of exposure)

Question 29

What are factors that determine the antiquaries activity of fluoride toothpaste

Answer 29

• Fluoride concentration
• Frequency of application
• Rinsing behaviours
When brushing takes place

Question 30

What is the effect of fluoride concentration

Answer 30

• 6-7 percent reduction in caries for every 500 ppm F increase in fluoride concentration
• Use of low fluoride formulations provide less anticaries benefit.
Choice of toothpaste depends on careful risk benefit assessment.

Question 31

What is the effect of frequency of application

Answer 31

More frequent brushing results in lower caries increments

Question 32

What is the effect of rinsing behavior

Answer 32

• Rinsing with a large volume of water removes excess fluoride and reduces fluoride in the mouth
Rinsing with small volumes of water removes excess fluoride and maintains fluoride in the mouth

Question 33

What is the effect of brushing habits

Answer 33

If someone brushes twice daily, doesn’t rinse using a beaker and uses 1500ppm toothpaste they will have a lower caries incidence than someone who does the opposite to these things

Question 34

What is the effect of toothpaste quantity

Answer 34

• Quantity of toothpaste does not have a strong effect on efficacy
Not a great difference in caries prevention

Question 35

What is the negatives to fluoride

Answer 35

• Efficacy of fluoridated toothpaste is clearly demonstrated
• The higher the fluoride content the greater the caries prevention
• Despite being topical, it is inevitable that there may be ingestion particularly in the young and this increases risk of enamel fluorosis
Therefore there should be a risk/benefit assessment between caries prevention and fluorosis risk

Question 36

What is the risk of fluoride use

Answer 36

• Risk results from ingesting fluoride
		○ Acute toxicity
			§ Very rare
			§ Generally potential problem in very young
		○ Chronic toxicity (fluorosis)
			§ Development defect in enamel

Question 37

What is the amount that is toxic for fluoride use

Answer 37

• The general consensus is that 0.1mg f/kg body weight is toxic
○ 1mg per day for a 1 year old
○ 2mg per day for 5-6 year old

Question 38

What is the limit for fluorosis

Answer 38

• Some say it is still possible to develop fluorosis at recommended daily intakes of 0.05-0.07 mg f/kg
• There is no lower limit below which fluorosis does not occur
There appears to be a dose response between fluoride exposure and fluorosis severity

Question 39

How is ingestion of fluoride minimized

Answer 39

• The bioavailibity of fluoride ingested from dentifrices is affected by stomach contents as stomach is a low pH so more bioavailable
  
  • Gastric absorption is rapid and complete in the absence of divalent and trivalent cations
  • Calcium, magnesium and aluminium form less soluble salts with reduced gastric absorption

Question 40

What are considerations regarding topical fluoride

Answer 40

• Quantity of toothpaste applied is not strongly associated with efficacy
  
  • Efficacy is primary concentration, not dose dependent as oral fluoride reservoir is small
  • Brush after meals - most effective at time of cariogenic challenge as pH is lower and if the fluoride is ingested then less is absorbed in the stomach but need to be careful as brushing is abrasive and you would be brushing a partially demineralised surface
  • Brush before bedtime - salivary flow rate is reduced so increased oral retention
  • Anti caries benefit is topical not systemic
  • Increased risk of developing fluorosis is systemic
  • Methods favouring topical delivery whilst minimising ingestion will have the best risk/benefit profile

Question 41

What can we do to maximize caries benefit but reduce fluoride risk in children

Answer 41

• Keep toothpaste out of reach of young children.
  
  • Brush frequently (twice daily: evening and one other time).
  • Supervise brushing by young children.
  • Use a small amount (pea/smear) of paste.
  • Discourage swallowing
  • Brush after meals to minimize effect of fluoride ingestion.
  • Encourage spitting out, remove slurry: avoid excessive rinsing.
  • Use a lower fluoride formulation if low caries risk, maximize fluoride concentration in relation to risk

Question 42

Where is community level prevention done

Answer 42

• Schools, nurseries, play groups
• Community groups, housing estates, local authority
○ Community health professionals (health visitor, DHSW, school nurse)
○ Local GMP surgery
○ Health centres
○ Shops
○ Shopping centres

Question 43

What are the community prevention tools

Answer 43

○ Fluoride 
			§ Tooth brushing schemes
			§ Fluoride varnish
		○ Diet 
			§ Healthy eating policies
			§ Free water/milk
			§ No sugary drinks
		○ Community at large
			§ Posting toothpaste home
			§ Out reach activities