Water Fluoridation

Question 1

quality of evidence

Answer 1

SIGN guideline 118, feb 2010

1++ High quality meta-analyses, systematic reviews of RCTs, or RCTs with a very low risk of bias

1+ Well conducted meta analyses, systematic reviews or RCTs with a low risk of bias

1- Meta analyses, systematic reviews or RCTs with a high risk of bias

2++ High quality systematic review of case control or cohort studies

High quality case control or cohort studies with a very low risk of confounding or bias and a high probability that the relationship is causal

2+ Well conducted case control or cohort studies with a low risk of confounding or bias and a moderate probability that the relationship is causal

2- Case control or cohort studies with a high risk of confounding or bias and a significant risk that t he relationship is not causal

3 Non-analytic studies, e.g. case reports, case studies

4 Expert Opinion

Question 2

anomalies in evidence can be due to

Answer 2

mistakes in survey gathering

Question 3

describe

Answer 3

clinical photograph

4 or 5 years (deciduous)

3 incisors grossly carious

Pain, before non-vital

Likely bottle fed caries

Question 4

what is Fluroide

Answer 4

• Fluoride is the anion of the element fluorine.
• Atomic symbol F,
• atomic number 9 (similar size to oxygen)
• Fluorine ~ non metal.
  
  • Halogen – they are found in the environment only in compounds or as ions
    13th commonest element

Question 5

Hydroxyapatite -> fluoroxyapatite

Answer 5

Ca5(PO4)3OH + F → Ca5(PO4)3F + OH

Question 6

intermediate CaF₂

importance in mineral structure

Answer 6

Packs tighter into Hydroxyapatite – post eruption more effective

Question 7

enamel formation

Answer 7

• Internal enamel epithelium induced by the dental papilla which was originally induced by the enamel organ or dental lamina – a migration of neural crest cells.
• Internal enamel epithelium produces ameloblasts for the enamel
• Dental papilla produces the odontoblasts for the dentine.

Preameloblasts initiated by dental papilla

• Elongate to become, secretory ameloblasts.

Ameloblasts stimulate dentinogenesis.

• Secretory stage, ameloblasts move from dentine.

Tomes’ processes angled, which gives differences in crystallite orientation and structure.

Differential movement leads to enamel rods.

Maturation stage, the ameloblasts mineralise the enamel – pre-eruptive fluoride action?

Question 8

water fluoridation

Answer 8

adjustment of fluoride ion to the UK optimum of 1ppm (1mg/l);

• 1ppm in a temperate climate.
  
  • Varies 0.5ppm ~ 1.2ppm;
  • related to ambient air temperature; latitude

Question 9

how is optimum level of fluoridation (1ppm F (1mg/l)) obtained in UK

Answer 9

• Hydrofluorosilicic acid or hexafluosilicic acid H₂SiF₆
• Sodium fluorosilicate or sodium silicofluoride, Na₂SiF₆

Question 10

history of water fluoridation

Answer 10

1901 Dr Frederick McKay dentist moved from Philadelphia to Colorado Springs

During 1909 dental inspection of 2,945 children.

• 87.5% had stain, all native to the region.

Colorado Brown Stain

• Stained teeth – dental fluorosis
• Only in lifelong residents
• Distinct geographical areas
• No more likely to have caries – less like

1920s – Brown stain from the water

1930s – assay for fluoride developed

1931 – H Trendley Dean studies in USA

Dose response – fluorosis and caries 1ppm optimal dose to minimise both

Question 11

first water fluoridation trial

Answer 11

1945

• Muskegon – negative control (source lake michigan)
• Grand Rapids – study town (source lake michigan)
• Aurora – positive control 1.2ppm

Results

• Grand Rapids – study town adjusted to 1ppm
• Muskegon – negative control (F < 0.2ppm)
  
  • (fluoridated in 1951 - results were so good)
• Aurora – positive control 1.2ppm

50 – 63% reduction in DMFT of 12/14-year-olds

48 – 50% reduction in DMFT of 15/16-year-olds

Question 12

forrest plot for systematic review of water fluoridation

Answer 12

Vertical line is no difference and we can see they all favour fluoridation.

One crosses the line so the difference is not statistically significant from zero, I bet they wished they had seen a larger sample

Question 13

Centre for NHS Reviews & Dissemination University of York, review of Water fluoridation

confimed

Answer 13

• 14.6% more children will be decay free mean reduction in dmft/DMFT of 2.25 teeth per child.

Confirms that fluoridation is effective.

review confirms that water fluoridation works -reduces tooth decay.

Question 14

is water fluoridation safe?

Answer 14

• no evidence of a link with adverse health effects, specifically bone fractures or cancers.
• The review found that water fluoridation is safe.

confirms that water fluoridation and brushing with fluoride toothpaste are complementary.

The only other population-based measure they could consider was the introduction of fluoride toothpaste

Question 15

enamel mottling / dental fluorosis

Answer 15

At 1ppm

• overall 48% prevalence of fluorosis
• 12.5% fluorosis of aesthetic concern

Enamel Mottling

• Staining, over 90 causes
• Later good UK studies (photographic)
  
  • 1% Non F
  • 4% with F – most mild or very mild
• Earlier possible publication / observer bias?

Question 16

water fluoridation and healthl inequalities

Answer 16

review confirms fluoridation is likely to reduce differences in severity of tooth decay between social classes among 5-year-old children.

review confirms that fluoridation is beneficial in reducing differences in severity of tooth decay between social classes among 5-year-old children (water fluoridation reduces dental health inequalities for this age group)

Question 17

water fluoridation - good or bad at improving inequalities?

Answer 17

‘In the majority of studies water fluoridation reduced dental caries inequalities between high and low social groups; in no study did water fluoridation increase inequalities’. Medical Research Council 2002

negative control - group that drinks fluoridated water

positive control - drinking slightly more

• see the steepness of the gradient showing the relationship between tooth decay and the Jarman score (just a measure of deprivation)

how water fluoridation reduces the steepness of the curve and levels the playing field when it comes to tooth decay

Question 18

ethical issue of water fluoridation ?

Answer 18

• Beneficial
• Has no harmful consequences
• Not infringe any basic human right
  
  • (no right to drink fluoride-free water – only a personal preference)
• Replicate a situation found naturally in some places
• Could be unethical not to fluoridate where practicable to do so

Question 19

current water fluoridation

Answer 19

• Scotland - 0% Natural fluoride, 0.04 – 0.5ppm
• USA 73% - 207 million
• Canada 45% - 32 million
• England 10% - 6 million
• ire 67% - 3 million
• Israel 70% - 4.2 million
• Australia 65% - 11.5 million
• New Zealand 61% - 2.3 million
• Singapore & Hong Kong - 100%

Question 20

act of water fluoridation

Answer 20

Water fluoridation is adjusting this natural fluoride concentration to 1ppm.

Scotland the level of fluoride in the water varies from 0.001 ppm to 1ppm.

Question 21

current legislation of water fluoridation in scotland

Answer 21

• Water (Fluoridation) Act 1985 (now consolidated into the 1991 Water Industry Act)
• No new water fluoridation anywhere in the UK
• Water Act 2003, Section 58 (Fluoridation of Water supplies) Applies in E &W

Question 22

UK study of water fluoridation effect

water fluoridation health monitioring report 2014

Answer 22

• Accounting for deprivation & ethnicity, 12-year olds in fluoride areas are 21% less likely to have had caries than in non-fluoride areas.
• The reduction in tooth decay in children in fluoridated areas appears greatest among those in the most deprived local authorities.
• study of fluoridated Newcastle and non-fluoridated Manchester found that of 12-year old children with moderate dental fluorosis or more (fluorosis score of TF4 and above) is very low, at around 1% in Newcastle and 0.2% in Manchester.
• No evidence of different cancer rates between fluoride and non-fluoride areas.

Question 23

why not introduced water fluoridation?

Answer 23

Scottish Oral Health Improvement Plan 24^th January 2018

• Although we recognise that water fluoridation could make a positive contribution to improvements in oral health, the practicalities of implementing this means we have taken the view that alternative solutions are more achievable.

Question 24

health economics of water fluoridation

Answer 24

Southcentral SHA consultation 2008

• Estimated capital cost of plant £471,000 for 160,000 people.
• Revenue costs are estimated £59,000 a year.
• Estimated to prevent decay in 36,032 teeth over 20 years.
  
  • The cost to prevent tooth decay; 32 pence per tooth.
    
    • 1 surface amalgam @ £9 or composite £17.

Cost benefit ratio of water fluoridation is 28:1 (900:32) for an amalgam filling or 53:1 (1700:32) for a composite

INVESTMENT

Question 25

stark dental health inequalities UK

Answer 25

2015 REPORT BY THE RCS – Improvements generally – but still not good enough. Regional diffeences AND INEQUALITY * 34% suffering in Leicester, compared * with just 2% in south Gloucestershire. THE NATIONAL CHILDRENS BUREAU WROTE IN 2015- * There are startling variations in young children's outcomes at regional and local authority level. Young children growing up in deprived areas tend to do worse than those living in less deprived areas. Unacceptable - GA extractions going up- 10% increase over last 4 yrs.