Gish 1966.
| Methods | Trial design: 2‐armed, double‐blind, placebo‐controlled and stratified RCT Location: USA Number of centres: Frankfort, Indiana, USA Recruitment period: study commenced in/before 1963 | |
| Participants | Inclusion criteria: not reported Exclusion criteria: not reported Baseline caries: 3.9 DMFS (Gp A: 3.99; Gp B: 3.99). Baseline characteristic (DMFS) "balanced" Age at baseline (years): range 6 to 14 years, mean 9.1 years (Gp A: 9.20; Gp B: 9.05). Baseline characteristic (age) "balanced" Sex: not reported Any other details of important prognostic factors: background exposure to fluoride in community water supply (0.9 ppm F) Number randomised: 500 (group numbers not reported) Number evaluated: 328 at 3 years (present at final assessment. Gp A: 165; Gp B: 163) Attrition: 34% dropout after 3 years (study duration = 5 years). Reasons for attrition not reported; any differential group losses not assessable | |
| Interventions | Comparison: FT versus PL Gp A (n = 165 evaluated): SnF2 1000 ppm F; Ca pyrophosphate abrasive system; home use/unsupervised, daily frequency assumed Gp B (n = 163 evaluated): placebo; Ca pyrophosphate abrasive system; home use/unsupervised, daily frequency assumed | |
| Outcomes | Primary: 3‐year DMFS increment ‐ cl + xr; DMFT (at 1, 2, 3, 4 and 5 years follow‐up) Secondary: none assessed Assessments irrelevant to this review's scope: none assessed Follow‐up duration: 5 years | |
| Notes | Adverse effects: not reported Funding source: Procter & Gamble, Cincinnati, USA Declarations/conflicts of interest: affiliations do not indicate immediate conflict of interests exist Data handling by review authors: examiners 1 and 2's reported assessments were pooled Other information of note: clinical (VT) caries assessment by 2 examiners, diagnostic threshold not reported. Radiographic assessment (5 to 7 BW), diagnostic threshold not reported. State of tooth eruption included not reported. Diagnostic errors not reported | |
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Unclear risk | Quote: "The children were stratified by past caries experience and dental age, and then assigned at random to test or control groups" Comment: not enough information provided |
| Allocation concealment (selection bias) | Unclear risk | No information provided |
| Blinding (performance bias and detection bias) All outcomes | Low risk | Quotes: "The dentifrices were packed in plain, white, coded tubes. The code was not known by either the subjects or the examiners" and "...those in group 2 received an identical dentifrice minus the stannous fluoride" 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: 34, 4% (172/500) in 3 years. Dropout by group: not reported. Reasons for losses: not reported Comment: numbers lost were not unduly high for length of follow‐up. It is unclear if there were any differential losses, and if reasons for missing outcome data are acceptable and balanced. Caries data pertain to participants present at final examinations (completing the relevant follow‐up exam) |
| Selective reporting (reporting bias) | Low risk | Outcomes reported:
DMFS increment ‐ cl + xr, reported at 1, 2, 3, 4 and 5 years follow‐ups
DMFT Comment: trial protocol not available. All pre‐specified outcomes were reported and were reported in the pre‐specified way |
| Baseline characteristics balanced? | Low risk | Prognostic factors reported: DFMS: 3.73 FT, 4.17 PL age: 9.27 FT, 9.25 PL Comment: initial caries appears balanced |
| Free of contamination/co‐intervention? | Low risk | Quote: "All of the children and their families received as much dentifrice as they wished, and no instructions were given to either group as to oral hygiene or frequency of use of either product" Comment: there is sufficient indication overall of prevention of contamination/co‐intervention |