Reed 1973.
| Methods | Trial design: 4‐arm, double‐blind, placebo‐controlled, RCT Location: USA Number of centres: not reported ("several elementary schools") Kansas City, Missouri, USA Recruitment period: study began in/before 1970 | |
| Participants | Inclusion criteria: not reported Exclusion criteria: not reported Baseline caries: 3.3 DMFS (Gp A: 3.36 DMFS (SE 0.158); Gp B: 3.39 DMFS (SE 0.172); Gp C: 3.47 DMFS (SE 0.163); Gp D: 3.46 DMFS (SE 0.165)). Baseline characteristics (DMFS, DMFT) "balanced" Age at baseline (years): range 6 to 14 years, mean 9 years (Gp A: 9.02 years; Gp B: 9.00 years; Gp C: 9.02 years; Gp D: 9.06 years). Baseline characteristic (age) "balanced" Sex: 1022 F:1082 M (Gp A: 252 F:279 M; Gp B: 264 F:273 M; Gp C: 251 F:262 M; Gp D: 255 F:268 M). Baseline characteristic (sex) "balanced" Any other details of important prognostic factors: Background exposure to fluoride: none reported. Community water supply not fluoridated. Number randomised: 2104 (Gp A: 531; Gp B: 537; Gp C: 513; Gp D: 523) Number evaluated: 1525 at 2 years (available at final examination) (Gp A: 379; Gp B: 387; Gp C: 362; Gp D: 397) Attrition: 28% dropout after 2 years (study duration = 2 years). Reasons for attrition not described; no differential group losses | |
| Interventions |
Comparison: FT (3 groups) versus PL
Gp A (n = 531): NaF 250 ppm F; abrasive system: high beta‐phase calcium pyrophosphate; home use/unsupervised, daily frequency assumed
Gp B (n = 537): NaF 500 ppm F; abrasive system: high beta‐phase calcium pyrophosphate; home use/unsupervised, daily frequency assumed
Gp C (n = 513): NaF 1000 ppm F; abrasive system: high beta‐phase calcium pyrophosphate; home use/unsupervised, daily frequency assumed Gp D (n = 523): placebo; abrasive system: high beta‐phase calcium pyrophosphate; home use/unsupervised, daily frequency assumed |
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| Outcomes | Primary: 2‐year DMFS increment ‐ cl + xr; DMFT (at 1, 2 years) Secondary: none assessed Assessments irrelevant to this review's scope: n/a Follow‐up duration: 2 years | |
| Notes | Adverse effects: not reported Funding source: not reported Declarations/conflicts of interest: not reported, institutional affiliation only Data handling by review authors: n/a Other information of note: clinical (VT) caries assessment by 1 examiner, diagnostic threshold not reported; state of tooth eruption included not reported. Radiographic assessment (up to 7 BW) by 1 examiner, diagnostic threshold not reported. Diagnostic errors not reported | |
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Low risk | Quote: "After initial clinical caries examination, children were placed in strata by age, sex and visual DMFS scores. Children within each strata were assigned by random permutation of four, to one of these dentifrices" |
| Allocation concealment (selection bias) | Unclear risk | No information provided |
| Blinding (performance bias and detection bias) All outcomes | Low risk | Quotes: "The dentifrices were similar in colour, flavour and other consumer properties and were supplied in coded tubes. Participants were not aware of the contents of the assigned dentifrice" and "The investigator was unaware of the dentifrice assignment for the participants during the examinations and radiographic interpretations" 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: 28% in 2 years. Dropout by group: 151/513 FT 1, 150/537 FT 2, 142/531 FT 3, 126/523 PL. Reasons for losses: not reported Comment: numbers lost were not unduly high given length of follow‐up with some differential losses between 2 groups (29.4% FT 1, 27.9% FT 2, 26.7% FT 3, 24.1% PL). 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) | Low risk | Outcomes reported:
DMFS increment ‐ cl + xr, reported at 1 and 2 years follow‐ups
DMFT 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:
DMFS: 3.36 (3.64) FT 1, 3.39 (3.99) FT 2, 3.47 (3.69) FT 3, 3.46 (3.77) PL DMFT: 2.32 (2.17) FT 1, 2.37 (2.41) FT 2, 2.45 (2.22) FT 3, 2.40 (2.26) PL gender: 279 M, 252 F FT 1; 273 M, 264 F FD2; 262 M, 251 F FT 3; 268 M, 255 F PL age: 9.02 FT 1, 9.00 FT 2, 9.02 FT 3, 9.06 PL Comment: initial caries appears balanced |
| Free of contamination/co‐intervention? | Low risk | Quote: "A family supply of the appropriate toothpaste (in coded tubes) and toothbrushes were distributed every 2 months..." Comment: there is sufficient indication overall of prevention of contamination/co‐intervention |