Manual 1: Topical Fluoride Flashcards
When can we use topical fluoride?
- to prevent carious lesions
- to manage existing carious lesions
What is the concentration of fluoride in topical fluoride?
- 22,600 ppm Fluoride
What quantity of fluoride to be used for age 2-5?
- 0.25ml max
What is the minimum age patient where you can use TF?
- minimum 2 years old
What quantity of fluoride to be used for age 6+?
- 0.4ml max
What are contraindications of topical fluoride? why?
- patients with allergy to colophony because there is wax in fluoride varnish
- patients with ulcerative gingivitis/stomatitis
- patients hospitalised due to severe allergy/asthma
How do you apply topical fluoride?
- inspect tooth
- dry the tooth: cotton wool, dry guard or saliva ejector
- clean tooth if needed, removing plaque with toothbrush
- apply topical fluoride interdentally first using micro-brush
- apply fluoride varnish to occlusal surface
- cover all occlusal surface and contact points
- Advice to patient; don’t eat or drink for 30 mins, don’t brush for minimum 4 hours.
how does fluoride prevent carious lesion?
- inhibits demineralisation
- makes enamel more resistant to erosion
- in high conc. it can inhibit bacterial metabolism / bacteriostatic (stops bacteria growing)
How does fluoride inhibit demineralisation?
- surface of tooth is made of HAP lattice
- HAP lattice composed of: OH ions - 3 calcium ions - 3 phosphate ions - 6 calcium ions
- bacteria convert sugar into acid (s. mutans convert sugar into lactic acid)
- the H+ ions from the acid combine with phosphate and hydroxide ions from the HAP lattice
- this breaks up the lattice and causes demineralisation of enamel
- fluoride in the varnish substitutes OH- ions in the HAP lattice to form FAP, the new lattice is more resistant to acid because it has lower solubility - the fluoride ions are smaller than OH so make the lattice tightly packed together.
- FAP tooth surface structure has higher resistant to acid so more resistant to caries and erosion: critical ph of HA is 5.5 vs FA is 4.5.
how does fluoride inhibit bacterial growth/ bacteriostatic?
Direct:
interacts with the enzyme enolase to reduce acid production:
- enzyme enolase is involved in glycolysis ( process of ATP production)
- if no ATP then bacteria cant reproduce so no acid will be produced
Indirect:
- limits phosphoenolpyruvate, where bacteria get energy from to absorb sugar, so it decreases amount of sugar entering bacteria so less acid produced.
- enters bacterial cell as hydrofluoric acid, reducing cell ph internally and preventing growth
- s.mutans are sensitive to fluoride
what is the problem with using a low concentration of fluoride in terms of bacteria?
- low conc. can cause bacterial resistance
how do we check if inter-proximal caries is cavitated?
- use floss, if it catches/frays then most likely cavitated
- use orthodontic separators, leave in for 3-5 days, ensure separator goes above and below contact point.
what is the most commonly used fluoride varnish? what is the conc. of fluoride in 1ml of varnish?
- Duraphat
- 1ml = 22,600 ppm F
what is the toxic dose of fluroide?
- 5mg per kg of body weight
how much of 1450 ppm F toothpaste would it take a 5 year old child who weighs 20kg to be intoxicated?
- we must know dose of fluoride in mg
- toxic dose for 5 year old child = 5mg x 20kg = 100mg
- toothpaste is 1450 ppm fluoride per 1 ml
- 1ml = 1 gram
- 1 ml = 1450ppm F
- 1 gram = 1000mg
- to find mg, 1450/1000 = 1.45mg per ml
- if toothpaste is 100ml, then the toothpaste is 145mg so it would take the child about 80% of tube to be intoxicated
