Buhe 1984.

Methods	Trial design: 3‐armed, double‐blind, placebo/active‐controlled and stratified RCT Location: West Germany (Federal Republic of Germany) Number of centres: not reported Recruitment period: study commenced 1976
Participants	Inclusion criteria: not reported Exclusion criteria: not reported Baseline caries: 17.4 DMFS (Gp A: 17.1; Gp B: 17.4; Gp C: 17.8 DMFS). Baseline characteristic (DMFS) "balanced" (DFS baseline data not reported) Age at baseline (years): range 11 to 13 years, mean 12.3 years (for all groups). Baseline characteristic (age) "balanced" Sex: not reported Any other details of important prognostic factors: data unavailable for site fluoridation status Number randomised: 1562 (Gp A: 520; Gp B: 520; Gp C: 522) Number evaluated: 1286 at 3 years (present at final assessment) (Gp A: 421; Gp B: 438; Gp C: 427) Attrition: 18% dropout after 3 years. No differential group losses
Interventions	Comparison: FT (2 groups) versus PL Gp A (n = 520): SMFP 1500 ppm F; IMP abrasive system; home use/unsupervised, daily frequency assumed Gp B (n = 520): SMFP 1000 ppm F; IMP abrasive system; home use/unsupervised, daily frequency assumed Gp C (n = 522): placebo; IMP abrasive system; home use/unsupervised, daily frequency assumed
Outcomes	Primary: 3‐year net DFS increment ‐ cl + xr; DMFS; DMFS (U); DMFT (at 3 years follow‐up) Secondary: none assessed Assessments irrelevant to this review's scope: none Follow‐up duration: 3 years
Notes	Adverse effects: not reported Funding source: supported by The Borrow Foundation Declarations/conflicts of interest: not reported Data handling by review authors: n/a Other information of note: clinical (VT) caries assessment, diagnostic threshold not reported; state of tooth eruption included = E/U; radiographic caries assessment, diagnostic threshold not reported
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Quote: "...stratified randomisation..." Comment: translation of report not detailed enough to make a categorical decision regarding sequence generation
Allocation concealment (selection bias)	Unclear risk	Translation of report not detailed enough to make a categorical decision regarding allocation concealment
Blinding (performance bias and detection bias) All outcomes	Low risk	Quotes: "Double blind study" and "...as compared to the placebo group.." Comment: blind outcome assessment and use of placebo described
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Overall dropout for length of follow‐up: 17.7% in 3 years. Dropout by group: FT 1: 99/520, FT 2: 82/520, PL: 95/522. Reasons for losses not reported Comment: numbers lost were not unduly high given length of follow‐up and showed no differential loss between groups. It is unclear if reasons for the missing outcome data are acceptable and balanced. Caries data used in the analysis pertain to participants present at final examination
Selective reporting (reporting bias)	Unclear risk	Outcomes reported: DFS increment ‐ cl + xr, reported at 3 years follow‐up DMFS DMFS (U) DMFT Comment: trial protocol unavailable. Translation of methods section not detailed enough to make a categorical decision regarding selective outcome reporting
Baseline characteristics balanced?	Low risk	Prognostic factors reported: mean age 12.3 years (for all groups) DMFS: 17.1 FT 1; 17.4 FT 2; 17.8 PL TAR: 15.4 FT 1; 15.5 FT 2; 15.3 PL Comment: initial caries appears balanced between groups
Free of contamination/co‐intervention?	Unclear risk	Translation of report not detailed enough to make a categorical decision regarding any contamination/co‐intervention