Naylor 1979.

Methods	Stratified random allocation; double‐blind (A); placebo‐controlled; 20% drop out (for all study groups combined) after 3 years (study duration = 3 years). Natural losses; any differential group losses not assessable.
Participants	625 children analysed at 3 years (available at final examination). Age range at start: 11‐12 years. Surfaces affected at start: 7.9 DFS. Background exposure to fluoride: none reported. Year study began: 1973. Location: UK.
Interventions	FT** versus PL (SMFP group = 1000 ppm F). Home use/unsupervised, daily frequency assumed. Abrasive system: Ca carbonate.
Outcomes	3yDFS increment ‐ (E) (CA)cl+(ER)xr. Reported at 3 years follow up. DFT. DFT (U). O‐BL‐DFS. MD‐DFS. CIR.
Notes	Participants randomised (numbers for relevant groups NR). Baseline characteristics (age, SAR, TAR, DFS, DFT) 'balanced'. Clinical (VT) caries assessment (FOTI used) by two examiners (independently); diagnostic threshold = CA; state of tooth eruption included = E/U. Radiographic assessment (2 postBW) by two examiners (independently); diagnostic threshold = ER. Results of one examiner chosen (findings consistent throughout) . **Ca glycerophosphate/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)	Unclear risk	B ‐ Unclear