Cochrane · intervention · CD010856

Water fluoridation for the prevention of dental caries

Iheozor‐Ejiofor, Z, Worthington, HV, Walsh, T, et al. · Cochrane Database of Systematic Reviews · 2015 · Cochrane Library

Oral Health Dental caries2 versionsAMSTAR 2: not assessed

Full textEvery question was extracted from the full review (methods and results), not only its Summary of Findings table.

Questions

current version

GRADE rated

No studies

Included studies

155

as reported

No studies 5 · 35.7%Ungraded 1 · 7.1%Very low 1 · 7.1%Low 7 · 50%Moderate 0 · 0%High 0 · 0%

Ungraded means an effect was reported without a GRADE rating; it is not a gap. No studies means the review found nothing to answer the question. The six categories are a display order, not a score.

Review question

Element	Planned (methods)	Found (results)
Population	Populations of all ages receiving fluoridated water (naturally or artificially) and populations receiving non-fluoridated water	Caries: children aged 3 to 16 years, mostly recruited from schools (20 studies). Fluorosis: populations of all ages, mostly children (135 studies), about 73% in areas of naturally occurring fluoride
Intervention	For caries: a change in the level of fluoride in the water supply of at least one study area within three years of the baseline survey (exposure to fluoridated or non-fluoridated water, less than 0.4 ppm, allowing similar other fluoride sources across groups). For fluorosis: fluoride at any concentration present in drinking water	Initiation of water fluoridation (n=18); Cessation of water fluoridation (n=1); Higher water fluoride concentration for fluorosis (n=135)
Comparison	Non-fluoridated water (0.4 ppm fluoride or less)	Low/non-fluoridated water, 0.4 ppm or less (n=20 caries studies); Lower water fluoride concentration (fluorosis dose-response, n=135)
Outcomes	Primary (caries): change in decayed, missing and filled deciduous and permanent teeth and surfaces (dmft/DMFT, dmfs/DMFS); incidence of dental caries; percentage of caries-free children; disparities in caries. Secondary (dental fluorosis): percentage of children with fluorosis (any level or of aesthetic concern); Dean's Fluorosis Index; Tooth Surface Index of Fluorosis (TSIF); Thylstrup and Fejerskov index (TFI); Modified Developmental Defects of Enamel (DDE). Other adverse effects (e.g. skeletal fluorosis, bone fracture) recorded narratively	Change in dmft (n=9); Change in DMFT (n=10); Change in DMFS (n=1); Change in proportion of caries-free children deciduous (n=10); Change in proportion of caries-free children permanent (n=8); Disparities in caries by SES (n=3); Dental fluorosis of aesthetic concern (n=40); Any dental fluorosis (n=90); Other adverse effects e.g. skeletal fluorosis/bone fracture (n=5)
Study designs	For caries: only prospective studies with a concurrent control comparing at least two populations, one receiving fluoridated and the other non-fluoridated water, with at least two points in time evaluated (initiation or cessation of fluoridation). For fluorosis: any study design with concurrent control comparing populations exposed to different water fluoride concentrations. Randomised controlled trials are unfeasible	Prospective observational controlled before-and-after studies (caries, n=20); observational studies, mostly cross-sectional, with concurrent control (fluorosis, n=135)
Timing	At least two points in time evaluated for caries data	Caries: time between baseline and final measurement 2 to 12 years. Fluorosis: cross-sectional

Search date: 2015-02. Databases: Cochrane Oral Health Group's Trials Register; Cochrane Central Register of Controlled Trials (CENTRAL); MEDLINE via OVID; EMBASE via OVID; Proquest; Web of Science Conference Proceedings; ZETOC Conference Proceedings

Questions and results

Current version only

Initiation of water fluoridation (artificial or natural) vs Low/non-fluoridated water (0.4 ppm fluoride or less)

Population: People of all ages in a community setting; the included caries studies were all in children aged 3 to 16 years

CD010856.PUB2 (current) · 7 questions

Outcome	Effect	Evidence	Status / GRADE
Caries in permanent teeth (change in DMFT) Follow-up 8 to 11 years same question in other reviews	MD -1.16 [-1.61, -0.72] Mean DMFT at follow-up in low/non-fluoridated areas 0.7 to 5.5 (median 4.4) vs Water fluoridation 1.16 lower (0.72 to…	10 studies · 78764 participants	Low Downgraded: risk of bias, indirectness
Disparities in caries across socioeconomic status (SES) same question in other reviews	There is insufficient information to determine whether initiation of a water fluoridation programme results in a change in disparities in caries levels across SES. Data from 3 observational studies (participants not…	3 studies · 35399 participants	Low Downgraded: risk of bias
Change in proportion of caries-free children (permanent teeth) Follow-up 8 to 12 years same question in other reviews	MD 0.14 [0.05, 0.23] Proportion caries-free at follow-up in low/non-fluoridated areas 0.01 to 0.67 (median 0.14) vs Water fluoridation 0.14…	8 studies · 53538 participants	Low Downgraded: risk of bias, indirectness
Dental caries in adults Adults Population: Adults same question in other reviews	No studies that aimed to determine the effectiveness of water fluoridation for preventing caries in adults met the review's inclusion criteria. There are no data to determine the effect of water fluoridation on caries…	0 studies	No studies
Caries in deciduous teeth (change in dmft) Follow-up 3 to 12 years same question in other reviews	MD -1.81 [-2.31, -1.31] Mean dmft at follow-up in low/non-fluoridated areas 1.21 to 7.8 (median 5.1) vs Water fluoridation 1.81 lower (1.31 to…	9 studies · 44268 participants	Low Downgraded: risk of bias, indirectness
Caries in permanent teeth (change in DMFS) Follow-up (single study, Hardwick 1982) Population: Children aged about 12 to 16 years (Hardwick 1982), community setting same question in other reviews	MD -2.46 [-3.81, -1.11]	1 study · 343 participants	Ungraded
Change in proportion of caries-free children (deciduous teeth) Follow-up 3 to 12 years same question in other reviews	MD 0.15 [0.11, 0.19] Proportion caries-free at follow-up in low/non-fluoridated areas 0.06 to 0.67 (median 0.22) vs Water fluoridation 0.15…	10 studies · 39966 participants	Low Downgraded: risk of bias, indirectness

Higher water fluoride concentration (fluoridated water; natural or artificial) vs Lower water fluoride concentration (concurrent control)

Population: Populations of all ages (mostly children) exposed to drinking water with differing fluoride concentrations

CD010856.PUB2 (current) · 2 questions

Outcome	Effect	Evidence	Status / GRADE
Dental fluorosis of aesthetic concern (Dean's Index, TFI, TSIF) Cross-sectional same question in other reviews	OR 2.90 [2.05, 4.10]	40 studies · 59630 participants	Low Downgraded: risk of bias, inconsistency
Dental fluorosis of any level (all severities) Cross-sectional same question in other reviews	OR 3.60 [2.86, 4.53]	90 studies · 180530 participants	Low Downgraded: risk of bias, inconsistency

Cessation of water fluoridation (fluoride removed from the water supply) vs Continued fluoridated water

Population: People of all ages in a previously fluoridated community (Maupome 2001: children with generally low caries experience)

CD010856.PUB2 (current) · 5 questions

Outcome	Effect	Evidence	Status / GRADE
Change in proportion of caries-free children (deciduous or permanent teeth) same question in other reviews	No evidence to determine the effect of the cessation of water fluoridation on the proportion of caries-free children.	0 studies	No studies
Caries in deciduous teeth (dmft/dmfs) same question in other reviews	No evidence to determine the effect of the cessation of water fluoridation on caries in deciduous teeth. No included study reported change in dmft following cessation.	0 studies	No studies
Caries in permanent teeth (DMFS) Follow-up 3 years same question in other reviews	Insufficient evidence to determine the effect of the cessation of water fluoridation on caries. One study (Maupome 2001), at high risk of bias, over 3 years found no increase in caries in the fluoride-ended group…	1 study · 9249 participants	Very low Downgraded: risk of bias
Disparities in caries across socioeconomic status (SES) same question in other reviews	No evidence to determine the effect of the cessation of water fluoridation on disparities in caries across SES.	0 studies	No studies
Adverse effects same question in other reviews	No evidence to determine whether cessation of a water fluoridation programme is associated with any harms.	0 studies	No studies

Water fluoridation, i.e. a change in the water fluoride level (artificial or natural) vs Non-fluoridated water (less than 0.4 ppm fluoride)

Population: Populations of all ages receiving fluoridated or non-fluoridated water

CD010856 · 1 question

Outcome	Effect	Evidence	Status / GRADE
Outcome NR At least two points in time evaluated (planned)	Protocol (no results). Planned comparison: effect of water fluoridation on dental caries.	0 studies	No studies

Water with fluoride at any concentration (higher fluoride exposure) vs Water with a lower fluoride concentration (concurrent control)

Population: Populations of all ages exposed to drinking water with differing fluoride concentrations

CD010856 · 1 question

Outcome	Effect	Evidence	Status / GRADE
Outcome NR	Protocol (no results). Planned comparison: effect of water fluoride concentration on dental fluorosis.	0 studies	No studies