Peterson 1979.

Methods	Stratified random allocation; double‐blind (A); placebo‐controlled; 25% drop out after 2.5 years (study duration = 2.5 years). Natural losses; exclusions based on presence in all follow‐up examinations; any differential group losses not assessable.
Participants	712 children analysed at 2.5 years (present for all examinations). Age range at start: 8‐12 years (average = 10). Surfaces affected at start: 2.9 DFS. Background exposure to fluoride: water. Year study began: 1971. Location: USA.
Interventions	FT (2 groups) versus PL (both SMFP groups = 1000 ppm F). School use/supervised, daily, (appropriate toothpastes also provided for home use). Abrasive system: Ca carbonate in one toothpaste and in placebo toothpaste, IMP in the other SMFP toothpaste.
Outcomes	2.5yDFS increment ‐ cl+xr. Reported at 2.5 years follow up. DMFT. MD‐DFS.
Notes	Participants randomised (N = 950); numbers by group NR. Baseline characteristics (DFS, MD‐DFS, DFT) 'balanced'. Clinical (VT) caries assessment (FOTI used) by one examiner; diagnostic threshold = CA; state of tooth eruption included NR; radiographic assessment (postBW) by one examiner; diagnostic threshold = ER. Diagnostic errors NR.
Risk of bias
Bias	Authors' judgement	Support for judgement
Allocation concealment (selection bias)	Unclear risk	B ‐ Unclear