James 1967.

Methods	Trial design: 2‐armed, double‐blind, placebo‐controlled RCT Location: UK Number of centres: 11 schools (5 grammar/high schools; 6 county secondary schools), Buckinghamshire Recruitment period: study commenced in 1962
Participants	Inclusion criteria: not reported Exclusion criteria: not reported Baseline caries: 11 DFS (Gp A: 10.73 DFS and DMFS; Gp B: 11.32 DFS and DMFS). Baseline characteristics (DFS, DFT, DMFS, DMFT) "balanced" Age at baseline (years): range 11 to 12 years (Gp A: 11.35 years; Gp B: 11.35 years). Baseline characteristic (age) "balanced" Sex: 518 F:525 M (Gp A: 268 F:262 M; Gp B: 250 F:263 M) Any other details of important prognostic factors: data unavailable for site fluoridation status Number randomised: 1043 (Gp A: 530; Gp B: 513) Number evaluated: 803 at 3 years (present at final assessment. Gp A: 406; Gp B: 397) Attrition: 23% dropout rate after 3 years (study duration = 3 years). Reasons for dropout described with respective total numbers: moved away, unco‐operative, not present on examination day, disliked toothpaste, staining of teeth, others; no differential group losses
Interventions	Comparison: FT versus PL Gp A (n = 530): SnF2 1000 ppm F; abrasive system: dicalcium pyrophosphate; home use/unsupervised, daily frequency assumed Gp B (n = 513): placebo; abrasive system: dicalcium pyrophosphate; home use/unsupervised, daily frequency assumed
Outcomes	Primary: 3‐year DFS increment ‐ (E) (CA) cl + (ER) xr; DFT; DMFS; DMFT; posterior MD‐DFS (at 3 years) Secondary: adverse effects (proportion of children who complained of tooth staining) (at 3 years) Assessments irrelevant to this review's scope: compliance Follow‐up duration: 3 years
Notes	Adverse effects: "Proportions of children with dark stain increased in all groups and the increase was significantly larger in test group children" Funding source: study funded by Procter & Gamble and "financial contribution from the Royal Dental Hospital Endowments Fund for the purchase of a counter‐sorter" Declarations/conflicts of interest: not reported Data handling by review authors: n/a Other information of note: clinical (VT) caries assessment by 1 examiner, diagnostic threshold = CA; state of tooth eruption included = E/U. Radiographic assessment (2 postBW) by 1 examiner, diagnostic threshold = ER. Diagnostic errors not reported
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "These children were divided, by sex and by school, into 2 groups, using a random number technique for designation into groups. Each school therefore contained approximately equal numbers of test and control children, with similar representation of boys and girls"
Allocation concealment (selection bias)	Unclear risk	No information provided
Blinding (performance bias and detection bias) All outcomes	Low risk	Quotes: "Children in the test group were supplied with stannous fluoride... dentifrice, while the control dentifrice was identical in colour, texture and flavour" and "Nobody involved in the study, except the manufacturers, knew the identity of the test dentifrice, and the double‐blind technique was maintained throughout the investigation" and "All radiographs were read by one of us at the end of the study without knowledge of group allocation" Comment: blind outcome assessment and use of placebo described
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Overall dropout for length of follow‐up: 23% in 3 years. Dropout by group: 124/530 FT, 116/513 PL. Reasons for losses: moved away (59 FT, 59 PL), unco‐operative (31 FT, 24 PL), not present on examination day (27 both groups), disliked toothpaste (3 FT, 2 PL), staining of teeth (2 FT, 2 PL), others (18 FT, 13 PL) Comment: numbers lost were not unduly high given the length of follow‐up with no differential losses between groups. It is unclear if reasons for the missing outcome data are acceptable and balanced between groups. Caries data used in analysis pertain to participants present at final examination
Selective reporting (reporting bias)	Low risk	Outcomes reported: DFS increment ‐ (E) (CA) cl + (ER) xr, reported at 3 years follow‐up DMFS DFT DMFT posterior MD‐DFS proportion of children with tooth staining Comment: trial protocol not available. All pre‐specified outcomes (in Methods) were reported and were reported in the pre‐specified way
Baseline characteristics balanced?	Low risk	Prognostic factors reported: DMFS: 10.73 FT, 11.32 PL age: 11.35 FT, 11.35 PL DFS: 10.73 FT, 11.32 PL DFT: 6.12 FT, 6.48 PL DMFT: 6.12 FT, 6.48 PL Comment: initial caries appears balanced
Free of contamination/co‐intervention?	Low risk	Quote: "It was decided to supply the whole of the subject's family with the appropriate dentifrice to reduce the risk of other brands being used during the test period" Comment: there is sufficient indication overall of prevention of contamination/co‐intervention