McInnes 1982.

Methods	FLUOROSIS STUDY Country of study: South Africa Geographic location: Kenhardt (F); Keimoes (non‐F); North‐western Cape Province Year of study: not stated Year of change in fluoridation status: NA Study design: cross sectional
Participants	Inclusion criteria: lifetime residents of study area; pre‐school children aged 1‐5 years Exclusion criteria: none stated Other sources of fluoride: majority of babies were breastfed so would not be exposed to fluoride from water used in preparation of infant formula Social class: reported as being the same across groups; experimental and control groups reported as being similar (parents were land or railway labourers) Ethnicity: all children same ethnic origin i.e. European‐African‐Malay origin Residential history: lifetime residents Other confounding factors: same climatic conditions in both areas
Interventions	All natural fluoridation Group 1: 2.2‐4.1 ppm Group 2: 0.2 ppm
Outcomes	Dental fluorosis (Dean's Index) Age at time of measurement: 1‐5 years
Funding	Part funded by South African Sugar Association
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Sampling	Unclear risk	Insufficient detail reported to determine how selection took place
Confounding	High risk	Malnutrition and SES were reported to be similar across groups but no supporting data provided Did not report any details about other sources of fluoride
Blinding of outcome assessment (detection bias) All outcomes	High risk	Did not undertake blinding
Incomplete outcome data (attrition bias) All outcomes	Low risk	Data appear to be presented for all participants
Selective reporting (reporting bias)	Low risk	All expected data appeared to be present
Other bias	Low risk	No other apparent bias