James 1977.

Methods	Trial design: 2‐armed, double‐blind, placebo‐controlled and stratified RCT Location: UK Number of centres: 12 schools in Shropshire Recruitment period: study commenced in 1970
Participants	Inclusion criteria: not reported Exclusion criteria: not reported Baseline caries: 11.2 DMFS (Gp A: 11.0 DMFS; Gp B: 11.4 DMFS). Baseline characteristic (DMFS) "balanced" Age at baseline (years): range 11 to 12 years (Gp A: mean 11.9 years; Gp B: mean 12.0 years). Baseline characteristic (age) "balanced" Sex: randomised 490 F:474 M; evaluated 397 F:385 M (Gp A: 204 F:199 M; Gp B: 193 F:186 M). Baseline characteristic (sex) "balanced" Any other details of important prognostic factors: data unavailable for site fluoridation status Number randomised: 964 (group distribution not reported) Number evaluated: 782 at 3 years (present at all assessments. Gp A: 403; Gp B: 379) Attrition: 19% dropout after 3 years (study duration = 3 years). Reasons for attrition not reported; exclusions based on presence in all follow‐up examinations; any differential group losses not assessable
Interventions	Comparison: FT versus PL Gp A (n = evaluated 403): SMFP 2400 ppm F; abrasive system: Al oxide trihydrate; home use/unsupervised, daily frequency assumed Gp B (n = evaluated 379): placebo; abrasive system: Al oxide trihydrate; home use/unsupervised, daily frequency assumed
Outcomes	Primary: 3‐year DMFS increment ‐ (CA) cl + (ER) xr; posterior MD‐DMFS; O‐DMFS; BL‐DMFS; O‐BL‐MD‐DMFS; anterior DMFS (at 3 years) Secondary: not assessed Assessments irrelevant to this review's scope: n/a Follow‐up duration: 3 years
Notes	Adverse effects: not reported Funding source: "supported by a grant from the Unilever Research Laboratories" Declarations/conflicts of interest: not reported Data handling by review authors: n/a Other information of note: clinical (VT) caries assessment by 2 examiners, diagnostic threshold = CA; radiographic assessment (2 postBW); state of tooth eruption included not reported. Inter‐ and intra‐examiner reliability for clinical and radiographic diagnosis revealed by re‐examination of 10% sample
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote: "After baseline examination, they were stratified by sex, school and level of caries experience and randomly allocated to one or other of two groups"  Comment: not enough information provided
Allocation concealment (selection bias)	Unclear risk	No information provided
Blinding (performance bias and detection bias) All outcomes	Low risk	Quotes: "... one of the groups was supplied with the dentifrice containing fluoride, while the other received the paste without it. The two dentifrices were identical in taste, appearance and texture, and the trial was conducted on a double‐blind basis" and "After the analysis the code was broken...."  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: 18.9% (182/964) in 3 years. Dropout by group: not reported. Reasons for losses: exclusion due to absence from any examination Comment: numbers lost were not unduly high for the length of follow‐up. It is unclear if there were any differential losses, and if reasons for missing outcome data are acceptable and balanced. Caries data used in analysis pertain to participants who took part in all examinations
Selective reporting (reporting bias)	Low risk	Outcomes reported: DMFS increment ‐ (E + U) (CA) cl, reported at 3 years follow‐up posterior MD‐DMFS O‐DMFS BL‐DMFS O‐BL‐MD‐DMFS anterior DMFS proportion of caries‐free teeth/surfaces (by tooth type/ surface type) which developed caries proportion of children who complained of 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: 11.0 FT, 11.4 PL mean age: 11.9 FT, 12.0 PL Comment: initial caries appears balanced
Free of contamination/co‐intervention?	Unclear risk	Quote: "The appropriate pastes were distributed by home visitors to the children's homes... they were not instructed to supervise or monitor the usage of the paste" Comment: not enough information provided