Marks 1994.
| Methods | Trial design: 5‐armed, double‐blind, stratified RCT Location: USA Number of centres: 25 elementary schools at baseline, Polk County, Florida; 39 schools overall (allowing for subjects followed‐up after moving to middle school) Recruitment period: study began 1983 | |
| Participants | Inclusion criteria: not reported Exclusion criteria: not reported Baseline caries: 2.5 DMFS (Gp A: 2.48 (SD 3.40); Gp B: 2.52 (SD 3.44); Gp C: 2.50 (SD 3.76); Gp D: 2.61 (SD 3.64); Gp E: 2.46 (SD 3.48)). Baseline characteristics (sound surfaces, DMFS, DMFT, DFS inter) "very well balanced" (evaluated subjects only) Age at baseline (years): range: 6 to 14 years; mean 9.6 years (Gp A: 9.6; Gp B: 9.6; Gp C: 9.6; Gp D: 9.7; Gp E: 9.7). Baseline characteristic (age) "very well balanced" (evaluated subjects only) Sex: 2717 F:2757 M (Gp A: 560 (50.0%) F:560 (50.0%) M; Gp B: 562 (50.4%) F:554 (49.6%) M; Gp C: 528 (49.1%) F:548 (50.9%) M; Gp D: 547 (49.2%) F:565 (50.8%) M; Gp E: 520 (49.5%) F:530 (50.5%) M). Baseline characteristic (sex) "very well balanced" (evaluated subjects only) Any other details of important prognostic factors: background exposure to fluoride in community water at baseline < 0.3 ppm F; new water fluoridation programs commenced during trial affecting 17 of 39 schools (44%), although levels not reported ("A separate analysis was done for the water‐fluoride children, and the results between dose groups were no different in schools having new water fluoridation than in schools not implementing water fluoridation") Number randomised: 8027 (Gp A: 1597; Gp B: 1615; Gp C: 1609; Gp D: 1604; Gp E: 1602) Number evaluated: 5474 at 3 years (Gp A: 1120; Gp B: 1116; Gp C: 1076; Gp D: 1112; Gp E: 1050) Attrition: 31.8% dropout (for all study groups combined) after 3 years (study duration = 3 years). Reasons for attrition not reported; no differential group losses | |
| Interventions |
Comparison: FT versus FT (5 groups)
Gp A (n = 1597): SMFP 1000 ppm F; abrasive system: silica; home use/supervised toothbrushing at school, daily frequency
Gp B (n = 1615): SMFP 1500 ppm F; abrasive system: silica; home use/supervised toothbrushing at school, daily frequency Gp C (n = 1609): SMFP 2000 ppm F; abrasive system: silica; home use/supervised toothbrushing at school, daily frequency Gp D (n = 1604): SMFP 2500 ppm F; abrasive system: silica; home use/supervised toothbrushing at school, daily frequency Gp E (n = 1602): NaF 2000 ppm F; abrasive system: silica; home use/supervised toothbrushing at school, daily frequency |
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| Outcomes | Primary: 3‐year DMFS increment ‐ cl xr; DMFT increment; DFS interproximal increment (at 3 years) Secondary: not assessed Assessments irrelevant to this review's scope: compliance Follow‐up duration: 3 years | |
| Notes | Adverse effects: not reported Funding source: grant from Chesebrough‐Pond's Inc (toothpaste manufacturer of Mentadent) Declarations/conflicts of interest: not reported Data handling by review authors: Gp A versus B versus C + E versus D in analysis. Summary data obtained from 1994 paper Other information of note: clinical caries assessment by 1 examiner. Analysis of covariance adjusting for baseline age, sex and DMFS. This is a re‐analysis of a previous study with inclusion of 2000 ppm NaF group | |
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Unclear risk | Quote: "... block randomisation scheme was used to balance study groups for age, sex and baseline experience.." |
| Allocation concealment (selection bias) | Unclear risk | Comment: insufficient information |
| Blinding (performance bias and detection bias) All outcomes | Low risk | Quotes: "double‐blind caries trial" and "All dentifrices were identical in appearance and flavour" Comment: although not stated examiners probably blinded to group |
| Incomplete outcome data (attrition bias) All outcomes | Unclear risk | Quote: "Attrition rates ranged from 29.9 per cent in 1000 ppm group to 34.5 in 2000 ppm NaF group and the overall attrition rate over all groups was 31.8 per cent" Comment: no reasons given for losses |
| Selective reporting (reporting bias) | Low risk | Comment: DMFT, DMFS, DFS on interproximal surfaces increments over 3 years reported |
| Baseline characteristics balanced? | Low risk | Comment: balance of age, sex, baseline caries. Analysis of covariance adjusting for baseline age, sex and DMFS |
| Free of contamination/co‐intervention? | Unclear risk | Comment: daily supervised toothbrushing and normal home use so contamination unlikely. Insufficient information |