Stephen 1988.
| Methods | Trial design: 6‐armed, double‐blind, head‐to‐head, stratified RCT Location: UK Number of centres: 12 secondary schools, Lanarkshire, Scotland, UK Recruitment period: study began 1983 | |
| Participants | Inclusion criteria: not reported Exclusion criteria: not reported Baseline caries: 10.2 DMFS (Gp A: 10.02 (SD 8.39); Gp B: 10.34 (SD 8.23); Gp C: 10.14 (SD 8.51)) and 10.2 DMFS zinc citrate trihydrate groups (Gp D: 10.10 (SD 7.89); Gp E: 10.01 (SD 8.29); Gp F: 10.42 (SD 8.53)). Baseline characteristics (baseline DMFS) "well balanced" Age at baseline (years): range 11 to 14 years, mean 12.55 years (group distribution not reported) Sex: 1199 F:1118 M (Gps A + D: 468 F:453 M; Gps B + E: 490 F:440 M; Gps C + F: 241 F:225 M) Any other details of important prognostic factors: background exposure to fluoride: not reported Number randomised: 3003 (Gp A: 599; Gp B: 600; Gp C: 299; Gp D: 596; Gp E: 603; Gp F: 306) Number evaluated: 2317 at 3 years (available at final examination) (Gp A: 469; Gp B: 464; Gp C: 239; Gp D: 452; Gp E: 466; Gp F: 227) Attrition: 23% dropout (for all study groups combined) after 3 years (study duration = 3 years). Reasons for attrition: excluded for non‐compliance, withdrew, absent at final examination; no differential group losses | |
| Interventions |
Comparison: FT (6 groups)a
Gp A (n = 599): SMFP 1000 ppm F; abrasive system: alumina trihydrate; home use/unsupervised, daily frequency assumed
Gp B (n = 600): SMFP 1500 ppm F; abrasive system: alumina trihydrate; home use/unsupervised, daily frequency assumed Gp C (n = 299): SMFP 2500 ppm F; abrasive system: alumina trihydrate; home use/unsupervised, daily frequency assumed Gp D (n = 596): SMFP 1000 ppm F + 0.5% zinc citrate trihydrate; abrasive system: alumina trihydrate; home use/unsupervised, daily frequency assumed Gp E (n = 603): SMFP 1500 ppm F + 0.5% zinc citrate trihydrate; abrasive system: alumina trihydrate; home use/unsupervised, daily frequency assumed Gp F (n = 306): SMFP 2500 ppm F + 0.5% zinc citrate trihydrate; abrasive system: alumina trihydrate; home use/unsupervised, daily frequency assumed |
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| Outcomes | Primary: 3‐year net DMFS increment ‐ cl + xr; DMFS increment by sex, clinician, tooth type, surface type (at 3 years) Secondary: none assessed Assessments irrelevant to this review's scope: n/a Follow‐up duration: 3 years | |
| Notes | Adverse effects: not reported Funding source: not reported Declarations/conflicts of interest: none reported Data handling by review authors: aTMP groups entered separately in analysis Other information of note: clinical (VT) caries assessment undertaken by 2 calibrated examiners. 5% re‐examined annually by allocated examiner and 5% by alternate examiner. Good intra‐ (0.92 to 0.99 clinical, 0.98 to 0.99 radiographic) and inter‐examiner (0.92 to 0.97 clinical, 0.99 radiographic) reliability | |
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Low risk | Quote: "... prospective participants were allocated sequential numbers ... one clinician saw all odd‐numbered .... the other all even‐numbered ... [following baseline examination] children were allocated to one of six toothpaste groups by stratified randomisation ... using computer constructed random number tables" |
| Allocation concealment (selection bias) | Unclear risk | Comment: insufficient information |
| Blinding (performance bias and detection bias) All outcomes | Low risk | Quotes: "double blind" and "The dentrifices were supplied in colour coded tubes, the particular composition of the toothpastes being unknown to the clinicians, home visitors or subjects" |
| Incomplete outcome data (attrition bias) All outcomes | Unclear risk | 2317/3044 available for analysis. Due to leaving the trial, excluded for non‐compliance, or absent at examination; did not alter balance between groups. 23% dropout rate at 3 years Comment: some participants were excluded for non‐compliance |
| Selective reporting (reporting bias) | Low risk | DMFS increment. Clinical and radiographic assessments |
| Baseline characteristics balanced? | Low risk | Comment: baseline caries scores from combined clinical/radiographic data comparable |
| Free of contamination/co‐intervention? | Low risk | Comment: no apparent cause for concern regarding contamination. Sufficient toothpaste supplied for whole family |