Mainwaring 1983.

Methods	Stratified random allocation; double‐blind (A); placebo‐controlled; 19% drop out (for all study groups combined) after 4 years (study duration = 4 years). Natural losses, no losses due to any adverse effects; any differential group losses not assessable.
Participants	682 children analysed at 4 years (available at final examination). Age range at start: 11‐12 years. Surfaces affected at start: 6.9 DFS. Background exposure to fluoride: none reported. Year study began: in/before 1978. Location: UK.
Interventions	FT (2 groups)** versus PL (SMFP group = 1000 ppm F, SMFP‐NaF group = 1000 ppm F). Home use/unsupervised, daily frequency assumed. Abrasive system: Ca carbonate in all toothpastes.
Outcomes	4yNetDFS increment ‐ (CA)cl+(ER)xr. Reported at 4 years follow up. O‐DFS. MD‐DFS. postMD‐DFS. MD‐BL‐DFS.
Notes	Participants randomised (numbers for relevant groups NR). Baseline characteristics (age, SAR, DFS, FS) 'balanced'. Clinical (VT) caries assessment (FOTI used) by one examiner; diagnostic threshold = CA; state of tooth eruption included NR. Radiographic assessment (2 postBW) by one examiner; diagnostic threshold = ER. Intra‐examiner reproducibility checks for DFS in 10% sample (icc for VT/XR over 0.95). **Ca glycerophosphate/SMFP toothpaste group not considered (additional non‐F active agent in this group only).
Risk of bias
Bias	Authors' judgement	Support for judgement
Allocation concealment (selection bias)	Unclear risk	B ‐ Unclear