CAR03-2004

Question 1

What foods can fluoride be found in?

Answer 1

Fish

Meat

Eggs

Tea leaves

Question 2

What did Dr Trendley Dean discover?

Answer 2

Fluoride levels up to 1ppm in drinking water did not cause fluorosis

Question 3

What is fluorapatite?

Answer 3

Compound similar to hydroxyapatite but OH- has been replaced by fluoride ions

Stronger and more resistant to acidic conditions (reduces cavity formation rate)

Question 4

How can pre-eruptive fluoride exposure be useful?

Answer 4

F- incorporated into crystal structure and present in enamel fluid

Enhances enamel structure by increasing crystal size and decreasing acid solubility

F- release on dissolution promotes remineralisation

Question 5

How does post-eruptive (topical) fluoride promote remineralisation?

Answer 5

Supersaturation of saliva allows F- to be incorporated into crystal structure = fluorapatite

Fluorapatite is less soluble so topical fluoride addition creates a supersaturated solution to increase thermodynamic driving force for mineralisation

Question 6

How does F- affect bacteria

Answer 6

Inhibits enolase which inhibits acid formation via glycolysis

Decreases extracellular polysaccharide formation (decreases adherence)

Bacteriocidal

Question 7

What community level fluoride interventions are used?

Answer 7

Water fluoridation

Salt fluoridation

Milk fluoridation

Question 8

Describe water fluoridation.

Answer 8

~5.8mil people in England, some areas are natural and depends on local authority

Systemic but action is topical and depends on frequency of water consumption

Pre-eruptive effects especially in pit and fissure areas of 6s

Added as sodium fluoride, hydrofluosilicic acid or sodium silicofluoride

Max permitted level = 1.5ppm, optimum = 0.7ppm

Question 9

What is the max permitted level of water fluoridation?

Answer 9

1.5ppm

Question 10

What is the optimum level of water fluoridation?

Answer 10

0.7ppm

Question 11

What can ppm also be expressed as?

Answer 11

mg/L

Question 12

What is the issue with salt fluoridation?

Answer 12

Promotes more salt consumption ~8-10g/day when WHO recommends only 5g/day

Question 13

What is the Blackpool fluoridated milk scheme?

Answer 13

The Borrow Foundation

F- added to milk for children

Concentration ranges from 2.5-7.5ppm

Question 14

What is an issue with milk fluoridation?

Answer 14

F- incompletely ionised in milk so post-eruptive effect is limited

Question 15

Describe fluoridated toothpaste action.

Answer 15

Highest level of evidence, used on individual level

Topical action

Creates a reservoir of F- in plaque to promote remineralisation when pH drops

Question 16

What fluoride compounds can be found in fluoride mouthrinses?

Answer 16

Sodium fluoride

Acidulated phosphate fluoride

Stannous fluoride

Ammonium fluoride

Amine fluoride

Question 17

Describe fluoride varnish action.

Answer 17

Duraphat = NaF at 22,600ppm

Topical = precipitates on enamel surface and creates a reservoir of F-

Question 18

What is the Childsmile programme and what are the cons of it?

Answer 18

In Scotland, fluoride varnish offered twice a year in priority nurseries and schools from 3 years old

Cons = requires personnel, time consuming, more expensive, requires access to dental services

Question 19

What can high doses of F- cause?

Answer 19

Acute effects:
GI = nausea, vomiting, diarrhoea, excessive salivation, cramps
Neurological = paresthesia, paresis, tetany, CNS depression, coma
Cardiovascular = weak pulse, hypotension, pallor, shock
Blood chemistry = acidosis, hypoglycaemia, hypomagnesemia

Question 20

What are the chronic effects of too much fluoride?

Answer 20

Skeletal fluorosis

Reproductive and developmental effects

GI and renal effects

Carcinogenicity and genotoxic effects

Question 21

What is required to give rise to chronic effects of too much F-?

Answer 21

Water fluoridation and another source (not just one cause usually)

Question 22

Describe dental fluorosis.

Answer 22

Chronic, fluoride-induced disruption of enamel development

Enamel is hypomineralised due to long-term excessive F- consumption

Common in areas with high levels of F- in drinking water (>1ppm)

Varies clinically from faint white spots to severe pitting and discolouration