Rule 1984.
| Methods | Trial design: 2‐armed, double‐blind, placebo‐controlled, stratified RCT Location: USA Number of centres: 7 schools in 3 semi‐rural North‐Eastern Connecticut communities Recruitment period: study began 1977 | |
| Participants | Inclusion criteria: not reported Exclusion criteria: not reported Baseline caries: 8.6 DMFS (Gp A: 8.28 DMFS (SE 0.25); Gp B: 8.72 DMFS (SE 0.27)). Baseline characteristics (TAR, DMFS, DMFT, DS, DT) "balanced" (DFS baseline data not reported) Age at baseline (years): range 9 to 12 years, mean 11 (Gp A: 11.30 years (SE 0.05); Gp B: 11.24 years (SE 0.05)). Baseline characteristic (age) "balanced" Sex: 551 F:603 M (Gp A: 275 F:320 M; Gp B: 276 F:283 M). Baseline characteristic (sex) "balanced" Any other details of important prognostic factors: background exposure to fluoride: community, home, school water supplies < 0.3 ppm F except for 1 school at 1.4 ppm F Number randomised: 1154 (Gp A: 595; Gp B: 559) Number evaluated: 876 at 2 years (present for all examinations) (Gp A: 460; Gp B: 416) Attrition: 24% dropout after 2 years (study duration = 2 years). Reasons for attrition not described; exclusions based on presence in all follow‐up examinations; no differential group losses | |
| Interventions | Comparison: FT versus PL Gp A (n = 595): SMFP 1000 ppm F; abrasive system: silica zerogel; school use/supervised, daily, for 1 min (appropriate toothpastes also provided for home use) Gp B (n = 559): placebo; abrasive system: silica zerogel; school use/supervised, daily, for 1 min (appropriate toothpastes also provided for home use) | |
| Outcomes | Primary: 2‐year DFS increment ‐ (E + U) (CA) cl + (ER) xr; O‐DFS; MD‐DFS; DFT; DMFS; DMFT(at 1, 2 years) Secondary: oral soft tissue lesions (at 1, 2 years) Assessments irrelevant to this review's scope: not reported Follow‐up duration: 2 years | |
| Notes | Adverse effects: "No lesions attributable to product use were noted" Funding source: grant from Lever Brothers Company Declarations/conflicts of interest: institutional affiliations reported only Data handling by review authors: n/a Other information of note: clinical (VT) caries assessment (FOTI used) by 1 examiner, diagnostic threshold = CA; state of tooth eruption included = E/U. Radiographic assessment (2 postBW) by 1 examiner, diagnostic threshold = ER. Reproducibility checks done in 10% sample clinically and radiographically | |
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Unclear risk | Quote: "Subjects were stratified according to school, grade and sex and randomly assigned to one of two 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 | Quote: "One group received the sodium monofluorophosphate dentifrice, and other group the placebo. The study was conducted under double‐blind conditions" 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% in 2 years. Dropout by group: 135/595 FT, 143/559 PL. Reasons for losses: exclusion based on presence at all examinations Comment: numbers lost were not unduly high given length of follow‐up with no differential losses 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 for all examinations |
| Selective reporting (reporting bias) | Low risk | Outcomes reported:
DFS increment ‐ (E + U) (CA) cl + (ER) xr, reported at 1 and 2 years follow‐ups DFT DMFS DMFT O‐DFS MD‐DFS oral soft tissue lesions Comment: trial protocol not available. All pre‐specified outcomes (in Methods) were reported and were reported in the pre‐specified way |
| Baseline characteristics balanced? | Low risk | Prognostic factors reported:
age: 11.30 FT, 11.24 PL TAR: 13.84 FT, 13.37 PL sex: 320 M, 275 F FT; 283 M, 276 F PL DMFS: 8.28 FT, 8.72 PL DMFT: 5.21 FT, 5.48 PL DS: 5.87 FT, 6.16 PL DT: 3.55 FT, 3.78 PL Comment: initial caries appears balanced |
| Free of contamination/co‐intervention? | Low risk | Quote: "Sufficient quantity were provided to ensure adequate supply for both students and families throughout the year, including summer vacation" Comment: there is sufficient indication overall of prevention of contamination/co‐intervention |