The Role of Fluoride in Caries Prevention and Management

Question 1

What are the two broad types of fluroide found in oral reservoir?

Answer 1

– Mineral deposits (CaF2; FAP)
* CaF2 in saliva and fluid phase of plaque
– Biologically/bacterially bound calcium-fluoride

Question 2

What is water fluroide supply?

Answer 2

o.8-1 ppm

Question 3

How does duraphat fluroide varnish work?

Answer 3

Colophony resin hardens in contact with saliva to maintain contact of fluoride with the tooth

mobilisation of calcium ions in the enamel precipitation of calcium fluroide

Question 4

How does the adsorption of fluroide work?

Answer 4

Rapid adsorption 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 months2

Question 5

How does calcium fluoride work?

Answer 5

acid attack intially causing the release of fluoride ions

then remineralisation

Question 6

What are acidulated mouthwashes and what do they do?

Answer 6

slightly acidic mouthrinses (with low ph)
* Stimulates mild demineralisation on tooth
surfaces
* Presence of fluoride remains
* Effective means of getting fluoride into teeth

Question 7

What dental material provides fluroide release?

Answer 7

glass ionomer

Question 8

How does fluoride work at the tooth surface?

Answer 8

– Presence of F during caries process alters demin/remin dynamics
– Partially demineralised crystals
– act as nucleators
– F ions adsorbed to crystal surface
– Attract Ca, P – new mineral formed
– FAP “veneer” (Fluroapatite + hydroxyapatite), lower solubility

Question 9

What are the factors determining the anticaries activity of fluroide toothpaste?

Answer 9

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

Question 10

What does a higher concentration of fluoride do to the efficacy of floride toothpaste?

Answer 10

increases it (quantity of toothpaste not strongly associated)

Question 11

What is optimal brushing habits?

Answer 11

• twice daily
• not using beaker
• 1500 ppm F paste

Question 12

What are risks of fluroride?

Answer 12

enamel fluorosis from ingestion (chronic toxicity in young children)
acute toxicity (very rare)

Question 13

How much fluoride do young children need to swallow to risk fluorosis?

Answer 13

General consensus ~ 0.1 mg f/kg body weight
– 1 mg per day for 1 year-old
– 2 mg per day for 5-6 year-old

Question 14

What is the bioavailability of fluoride affected by?

Answer 14

gastric contents

Gastric absorption is rapid and complete in the absence of divalent and trivalent cations found in toothpaste

Ca2+, Mg2+ and Al3+ form less soluble salts with reduced gastric absorption

Question 15

When should you brush?

Answer 15

• Brush after meals – most effective at time of cariogenic challenge/less readily absorbed.
• Brush before bedtime - salivary flow rate reduced/increased oral retention.

Question 16

What can we do to maximize caries benefit but reduce fluorosis risk in young children?

Answer 16

• 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 .