Fogels 1979.

Methods	Random allocation; double‐blind (A); placebo‐controlled; 40% drop out after 3 years (study duration = 3 years). Reasons for attrition described: graduations, change of residence/school, parental requests, and ortho treatment; no differential group losses.
Participants	1339 children analysed at 3 years (available at final examination). Age range at start: 6‐11 years (average = 9). Surfaces affected at start: 4.9 DFS. Background exposure to fluoride: none reported. Year study began: 1972. Location: USA.
Interventions	FT (2 groups) versus PL (both SnF2 groups = 1000 ppm F). Home use/unsupervised, daily frequency assumed. Abrasive system: silica gel in one SnF2 and placebo toothpaste, Ca pyrophosphate in the other.
Outcomes	3yNetDFS increment ‐ (CA)cl+(ER)xr. Reported at 3 years follow up. MD‐DFS. DFS (U). DMFT. Oral soft tissues lesions (data NR). Proportion of children with tooth staining (data NR).
Notes	Participants randomised (N = 2218). Baseline characteristics (DFS) 'balanced'. Clinical (VT) caries assessment by two examiners, diagnostic threshold = CA. Radiographic assessment (postBW) by two examiners; diagnostic threshold = ER. State of tooth eruption included E/U. Results shown for each examiner and for the pooled data from both (F‐ratios less than unit for examiner by treatment interactions); combined results considered.
Risk of bias
Bias	Authors' judgement	Support for judgement
Allocation concealment (selection bias)	Unclear risk	B ‐ Unclear