Kinkel 1972.
| Methods | Trial design: 2‐armed, double‐blind, placebo‐controlled RCT Location: Switzerland Number of centres: 37 elementary school classes from the Basel‐Landschaft canton Recruitment period: study commenced in/before 1969 | |
| Participants | Inclusion criteria: children 10 years of age Exclusion criteria: not reported Baseline caries: 2.2 DMFS (Gp A: 2.21 DMFS; Gp B: 2.29 DMFS). Baseline characteristic (DMFS) "balanced" Age at baseline (years): mean 10 years (age by group not reported) Sex: not reported (age by group not reported) Any other details of important prognostic factors: background exposure to fluoride not reported Number randomised: 927 (group numbers not reported) Number evaluated: 699 at 3 years (Gp A: 354; Gp B: 345) Attrition: 25% dropout rate after 3 years (study duration = 7 years). Reasons for dropout not described; any differential group losses not assessable | |
| Interventions | Comparison: FT versus PL Gp A (n = evaluated 354): SMFP F concentration not reported; abrasive system: not reported; home use/unsupervised, daily frequency assumed Gp B (n = evaluated 345): placebo; abrasive system: not reported; home use/unsupervised, daily frequency assumed | |
| Outcomes | Primary: 3‐year DMFS increment ‐ (CA) cl + (DR) xr (at 1, 2, 3, 4, 5 and 7 years) Secondary: none assessed Assessments irrelevant to this review's scope: none Follow‐up duration: 7 years | |
| Notes | Adverse effects: incidence of metabolic disorders measured. No events reported
Funding source: toothpaste was provided by Mibelle AG, Kasmetik und Seifenfabrik der Migros Declarations/conflicts of interest: not reported Data handling by review authors: n/a Other information of note: clinical (V) caries assessment, diagnostic threshold = CA and NCA; state of tooth eruption included not reported. Radiographic assessment (2 postBW), diagnostic threshold = DR and ER |
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| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Unclear risk | Quote: "... randomly allocated" 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 | Unclear risk | Overall dropout for length of follow‐up: 24.6% (228/927) in 3 years. Dropout by group: not reported. Reasons for losses: not reported Comment: numbers lost were not unduly high for the 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 used in analysis pertain to participants present at final examination |
| Selective reporting (reporting bias) | Unclear risk | Outcomes reported: DMFS increment ‐ (CA) cl + (DR) xr, reported at 1, 2, 3, 4, 5 and 7 years follow‐ups 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: DMFS: 2.21 FT, 2.29 PL Comment: initial caries appears balanced |
| Free of contamination/co‐intervention? | Unclear risk | Translation of report not detailed enough to make a categorical decision regarding any contamination/co‐intervention |