Andlaw 1975.

Methods	Stratified random allocation; double‐blind (A); placebo‐controlled; 13% drop out after 3 years (study duration = 3 years). Main reasons for attrition described: moved away, absent at final examination; no differential group losses.
Participants	740 children analysed at 3 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: 1970. Location: UK.
Interventions	FT versus PL (SMFP group = 1000 ppm F). Home use/unsupervised, daily frequency assumed. Abrasive system: Al oxide trihydrate.
Outcomes	3yNetDFS increment ‐ (E+U)(CA)cl+(ER)xr. Reported at 3 years follow up. DMFS. DFT. DMFT. PF‐DMFS. MD‐BL‐DMFS. MD‐DMFS. O‐DMFS. ECSI.
Notes	Participants randomised (N = 846). Baseline characteristics (age, dental age, TAR, DFS, DMFS, DFT, DMFT, ECSI) 'balanced'. Clinical (VT) caries assessment by two examiners; diagnostic threshold = CA. Radiographic assessment (2 postBW) by two examiners; diagnostic threshold = ER. State of tooth eruption included = E/U. Reproducibility ratio was less than 0.22 for intra‐examiner reproducibility of clinical and radiographic caries diagnosis; "significant differences between examiners could not have affected caries increment figures since each examined same children annually".
Risk of bias
Bias	Authors' judgement	Support for judgement
Allocation concealment (selection bias)	Unclear risk	B ‐ Unclear