Hodge 1980.

Methods	Stratified random allocation; double‐blind (A); placebo‐controlled; 18% drop out after 3 years (study duration = 3 years). Reasons for attrition described with respective total numbers: 158 left school, 14 withdrawn by own choice, 8 lack of co‐operation; any differential group losses not assessable.
Participants	799 children analysed at 3 years (available at final examination). Age range at start: 11‐12 years. Surfaces affected at start: 7.3 DMFS. Background exposure to fluoride: none reported. Year study began: in/before 1976. Location: UK.
Interventions	FT (3 groups) versus PL (SMFP group = 1000 ppm F, both SMFP‐NaF groups = 1450 ppm F). School use/supervised, daily, for 1 min (appropriate toothpastes also provided for home use). Abrasive system: alumina (in placebo toothpaste, SMFP and in one SMFP‐NaF toothpaste), dicalcium phosphate (in another SMFP‐NaF toothpaste).
Outcomes	3yNetDFS increment ‐ (E) (CA)cl+(DR)xr. Reported at 3 years follow up. DMFT.
Notes	Participants randomised (N = 979); numbers by group NR. Baseline characteristics (DMFS, DMFT, SAR) 'balanced' (DFS baseline data NR). Clinical (VT) caries assessment by one examiner; diagnostic threshold = CA; state of tooth eruption included = E/U; radiographic assessment (2 postBW) by one examiner; diagnostic threshold = DR. Reproducibility checks done in 10% sample clinically and radiographically (icc of incremental data between 0.92 and 0.97).
Risk of bias
Bias	Authors' judgement	Support for judgement
Allocation concealment (selection bias)	Unclear risk	B ‐ Unclear