Ripa 1988.
| Methods | Trial design: 3‐armed, double‐blind, head‐to‐head, stratified RCT Location: USA Number of centres: 2 school districts in 20 mile range (number of schools not reported), Long Island, New York, USA Recruitment period: study began 1982 | |
| Participants | Inclusion criteria: not reported Exclusion criteria: not reported Baseline caries: 3.8 DMFS (Gp A: 3.71 DMFS (SD 4.00); Gp B: 3.92 DMFS (SD 4.10); Gp C: 3.91 DMFS (SD 4.41)). Baseline characteristic (baseline DMFS) "comparable" Age at baseline (years): range 9 to 15 years, mean 11.7 (Gp A: 11.7 years; Gp B: 11.7 years; Gp C: 11.7 years). Baseline characteristic (age) "comparable" Sex: distribution not reported. Baseline characteristic (sex) reported to be "comparable" Any other details of important prognostic factors: background exposure to fluoride: community water supply < 0.1 ppm F Number randomised: 3785 (Gp A: 1242; Gp B: 1250; Gp C: 1293) Number evaluated: 2509 at 3 years (available at final examination) (Gp A: 827; Gp B: 824; Gp C: 858) Attrition: 34% dropout (for all study groups combined) after 3 years (study duration = 3 years). Reasons for attrition: change of residence (54%), withdrew (27.4%), orthodontically banded, absent at final examination; no differential group losses | |
| Interventions |
Comparison: FT (3 groups)
Gp A (n = 1242): SMFP 1000 ppm F; abrasive system: IMP then dicalcium phosphate dihydrate; home use/unsupervised, daily frequency assumed Gp B (n = 1250): combination 1000 ppm F (SMFP 500 ppm F + NaF 500 ppm F); abrasive system: silica; home use/unsupervised, daily frequency assumed Gp C (n = 1293): combination 2500 ppm F (SMFP 1250 ppm F + NaF 1250 ppm F); abrasive system: silica; home use/unsupervised, daily frequency assumed |
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| Outcomes | Primary: 3‐year DMFS increment ‐ cl; DMFS increment by surface (at 3 years). DMFT results reported for 2‐year follow‐up only Secondary: none assessed Assessments irrelevant to this review's scope: compliance Follow‐up duration: 3 years | |
| Notes | Adverse effects: not reported Funding source: partial funding by National Institute of Dental Research, US Public Health Service, Contract no. NO1DE12431. Other partial source not reported Declarations/conflicts of interest: institutional affiliations reported Data handling by review authors: groups A + B versus C in analyses Other information of note: clinical caries assessment by 2 calibrated examiners, whose results were pooled and analysed together. No values for reliability | |
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Unclear risk | Quotes: ".... stratified according to age, sex, and initial caries score and were randomly assigned to one [of] three dentrifice groups" and "randomly assigned to one of three dentifrice groups" |
| Allocation concealment (selection bias) | Unclear risk | Comment: insufficient information |
| Blinding (performance bias and detection bias) All outcomes | Low risk | Quotes: "A double‐blind protocol was used" and "... dentrifices were identically packaged in plain white tubes except for subject's name and code number on a plain label" |
| Incomplete outcome data (attrition bias) All outcomes | Unclear risk | 2509/3785 available at 3 years. Attrition mainly due to moving away from area; did not alter balance between groups. 34% dropout at 3 years; unlikely to be due to intervention Comment: some participants were withdrawn |
| Selective reporting (reporting bias) | Low risk | Clinical assessments only |
| Baseline characteristics balanced? | Low risk | Comment: comparable values for age, sex and DMFS at baseline |
| Free of contamination/co‐intervention? | Low risk | Comment: no apparent cause for concern regarding contamination. Participant's siblings assigned same toothpaste. Toothpaste clearly labelled with participant's name. Compliance assessed by telephone |