Naylor 1967.

Methods	Stratified random allocation; double‐blind (A); placebo‐controlled; 17% drop out (for all study groups combined) after 3 years (study duration = 3 years). Natural losses; any differential group losses not assessable.
Participants	973 children analysed at 3 years (available at final examination). Age range at start: 11‐12 years. Surfaces affected at start: 9.5 DMFS. Background exposure to fluoride: none reported. Year study began: 1961. Location: UK.
Interventions	FT** versus PL (SnF2 group = 1000 ppm F). Home use/unsupervised, daily frequency assumed. Abrasive system: IMP (main abrasive) in fluoride toothpaste, dicalcium phosphate (dihydrate) in placebo toothpaste.
Outcomes	3ycrudeDFS increment ‐ (E+U) (CA)cl+(ER)xr. Reported at 3 years follow up. DMFT. DMFS. postMD‐DFS. 1stmoMD‐DFS. Proportion of children with tooth staining.
Notes	Participants randomised (numbers for relevant groups NR). Baseline characteristics (age, gender, SAR, DMFS, DMFT, postMD‐DFS) 'balanced'. Clinical (VT) caries assessment by one examiner; diagnostic threshold = CA; state of tooth eruption included = E/U. Radiographic assessment (2 postBW) by one examiner; diagnostic threshold = ER. Reversal rate less than 4% of observed DFS increment in all groups. High accuracy of diagnosis revealed by 10% sample checks (clinically and radiographically). **Na N‐lauroyl sarcosinate/SMFP toothpaste group not considered (additional non‐F active agent used in this group only).
Risk of bias
Bias	Authors' judgement	Support for judgement
Allocation concealment (selection bias)	Low risk	A ‐ Adequate