Held 1968b.
| Methods | Trial design: 2‐armed, double‐blind, placebo‐controlled and stratified RCT Location: France Number of centres: 1 Recruitment period: study commenced in 1961 | |
| Participants | Inclusion criteria: males born in 1944, 1945 and 1946 and residing in French institution (Meudon)
Exclusion criteria: not reported
Baseline caries: 10.2 DMFS (Gp A: 13.7 DMFS/7.1 DMFT; Gp B: 7.0 DMFS/4.3 DMFT). Baseline characteristics (DMFS, DMFT) not balanced
Age at baseline (years): mean 15 years Sex: all male Any other details of important prognostic factors: data unavailable for site fluoridation status Number randomised: 85 (Gp A: 44; Gp B: 41) Number evaluated: 32 at 2 yearsa (present at interim 2‐year assessment. Gp A: 14; Gp B: 18) Attrition: 62% dropout after 2 years (study duration = 3 years). Reasons for high dropout due to age range at which many leave the institutions; no differential group losses |
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| Interventions | Comparison: FT versus PL Gp A (n = 44): NaF 500 ppm F; abrasive system: not clearly specified (silica used); institution use/supervised, twice a day Gp B (n = 41): placebo; abrasive system: not clearly specified (silica used); institution use/supervised, twice a day | |
| Outcomes | Primary: 2‐yeara DMFS increment ‐ (E) cl; DMFT (reported at 2 and 3 years follow‐up) Secondary: none reported Assessments irrelevant to this review's scope: annual CAR Follow‐up duration: 3 years | |
| Notes | Adverse effects: not reported Funding source: not reported Declarations/conflicts of interest: not reported Data handling by review authors: aresults for 3 years follow‐up not considered due to very high dropout rate Other information of note: clinical (VT) caries assessment by 1 examiner, diagnostic threshold not reported; state of tooth eruption included = E. Intra‐examiner reproducibility checks done | |
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Unclear risk | Quote: "...distributed at random to 2 groups" Comment: translation of report not detailed enough to make a categorical decision regarding sequence generation |
| Allocation concealment (selection bias) | Unclear risk | No information provided |
| Blinding (performance bias and detection bias) All outcomes | Low risk | Quote: "double blind study" Comment: blind outcome assessment and use of placebo described |
| Incomplete outcome data (attrition bias) All outcomes | High risk | Overall dropout for length of follow‐up: 62.4% in 2 years. Dropout by group: 30/44 FT, 23/41 PL. Reasons for losses: participants leaving school Comment: numbers lost are unduly high for length of follow‐up, with differential losses between groups (68%, 56%). Reasons for the missing data are not balanced between groups. Caries data used in analysis pertain to participants present at each examination |
| Selective reporting (reporting bias) | Unclear risk | Outcomes reported:
DMFS increment ‐ (E) cl, reported at 2 years follow‐up
DMFT annual CAR Comment: trial protocol unavailable. Translation of methods section not detailed enough to make a categorical decision regarding selective outcome reporting |
| Baseline characteristics balanced? | High risk | Prognostic factors reported: DMFS: 13.7 FT, 7.0 PL DMFT: 7.1 FT, 4.3 PL Comment: initial caries (DMFS) appears imbalanced |
| Free of contamination/co‐intervention? | Unclear risk | Translation of report not detailed enough to make a categorical decision regarding any contamination and/or co‐intervention |