Holdcroft 1999.

Methods	CARIES STUDY Country of study: England Geographic location: north Birmingham and Sandwell (F), North Staffordshire, Herefordshire and Shropshire (non‐F) Year study started: 1985/6 Year of change in fluoridation status: 1986 Study design: CBA
Participants	Inclusion criteria: not stated Exclusion criteria: not stated Other sources of fluoride: not Stated Social class: measured using Jarman scores Ethnicity: not stated Residential history: not stated Other confounding factors: not stated
Interventions	Initiation of water fluoridation Group 1: not stated Group 2: not stated
Outcomes	dmft Age at baseline measure: not stated Age at final measure: not stated
Funding	Not stated
Notes	Data from original CRD review (unverified data)
Risk of bias
Bias	Authors' judgement	Support for judgement
Sampling	Unclear risk	Unable to make a judgement as study was unavailable
Confounding	High risk	Data does not appear to have been controlled for SES and use of fluoride from other sources
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Unable to make a judgement as study was unavailable
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Unable to make a judgement as study was unavailable
Selective reporting (reporting bias)	Unclear risk	Unable to make a judgement as study was unavailable
Other bias	Unclear risk	Unable to make a judgement as study was unavailable