Blinkhorn 1983.
| Methods | Trial design: 4‐armed, double‐blind, placebo‐controlled and stratified RCT Location: UK Number of centres: 7 secondary schools, Greater Manchester, UK Recruitment period: study commenced in 1972 | |
| Participants | Inclusion criteria: not reported Exclusion criteria: not reported Baseline caries: 8.2 DMFS (Gp A: 7.83 DMFS (SD 5.17); Gp B: 8.48 DMFS (6.29)). Baseline characteristics (DMFS, DMFT, SAR) "balanced" (DFS baseline data not reported) Age at baseline (years): 11 to 12 years (not reported by group) Sex: 225 F:143 M (groups relevant to review: Gp A: 115 F:69 M; Gp B: 110 F:74 M) (evaluated participants only) Any other details of important prognostic factors: no background exposure to fluoride was reported. Fluoride content of the water supplies was less than 0.10 mg/L Number randomised: 826 (groups relevant to review: 410: Gp A: 205; Gp B: 205) Number evaluated: 751 at 3 years (present at final assessment. Groups relevant to review: 368: Gp A: 184; Gp B: 184) Attrition: 10% dropout after 3 years. Reasons for attrition described with respective total numbers for all 4 arms: 57 left school, 12 withdrawn by parents, 6 absent at final examination; no differential group losses: Gp A: 21/ 205; Gp B: 21/205 | |
| Interventions | Comparison: FT versus PL Gp A (n = 205): SMFP 1000 ppm F; IMP (main abrasive) abrasive system; school use/supervised, daily, for 1 min, post‐brushing water rinse done. FT provided to all groups for use at home Gp B (n = 205): placebo; IMP (main abrasive) abrasive system; school use/supervised, daily, for 1 min, post‐brushing water rinse done. FT provided to all groups for use at home | |
| Outcomes | Primary: 3‐year net DFS increment ‐ (E+U) (CA) cl + (DR) xr; PF‐DFS; MD‐BL‐DFS; MD‐DFS; posterior MD‐DFS; DMFT; DMFT (U); anterior DMFT; posterior DMFT; DFS (U) (at 3 years follow‐up) Secondary: none assessed Assessments irrelevant to this review's scope: SAR Follow‐up duration: 3 years | |
| Notes | Adverse effects: not reported Funding source: "supported from a grant from the Colgate‐Palmolive Company" Declarations/conflicts of interest: none reported Data handling by review authors: study contained 4 arms. Gp 1: fluoride paste + fluoride rinse; Gp 2: placebo paste + placebo rinse; Gp 3: fluoride paste + placebo rinse; Gp 4: placebo paste + fluoride rinse. Only Gps 2 (Gp B) and 3 (Gp A) are used in this review Other information of note: clinical (V) caries assessment by 1 examiner, diagnostic threshold = CA. Radiographic assessment (1 postBW) by 1 examiner, diagnostic threshold = DR. State of tooth eruption included = E/U. Intra‐examiner reproducibility checks for incremental clinical and radiographic caries data in 10% sample (ICC score 0.9) | |
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Unclear risk | Quote: "The children were allocated to four groups by stratified random sampling at two levels: school and dental age" Comment: not enough information provided |
| Allocation concealment (selection bias) | Unclear risk | No information provided |
| Blinding (performance bias and detection bias) All outcomes | Low risk | Quotes: "The trial was organized on a double‐blind basis, neither the children nor the examiner being aware of who was receiving test or control products" and "...another group used the fluoride dentifrice..... and a fourth group....a placebo dentifrice" 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: 10% in 3 years. Dropout by group: 21/ 205 FT, 21/205 PL. Reasons for losses: left school (57), withdrawn by parents (12), absent at final examination (6) (not reported by group) Comment: numbers lost were not unduly high for the length of follow‐up with no differential loss between groups. It is unclear if reasons for missing outcome data are acceptable and balanced. Caries data used in analysis pertain to participants present at final examination |
| Selective reporting (reporting bias) | Low risk | Outcomes reported:
DFS increment (E+U) (CA) cl + (DR) xr, reported at 3 years follow‐up
PF‐DFS
MD‐BL‐DFS
MD‐DFS posterior MD‐DFS DFS (U) DMFT anterior DMFT posterior DMFT DMFT (U) 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:
DMFT: 4.94 (2.86) FT, 5.26 (3.47) PL DMFS: 7.83 (5.17) FT, 8.48 (6.29) PL SAR: 93.41 (21.30) FT, 93.61 (20.43) PL Comment: initial caries appears balanced between groups |
| Free of contamination/co‐intervention? | Low risk | Quote: "..both dentifrice tubes and rinse bottles were colour coded so that the children received the correct products. Independent laboratory checks of the dispensed rinse and dentifrice were made at regular intervals to assess the reliabilty of the supervisors who dispensed agents. The coded dentifrice and rinse was dispensed in the school..." Comment: there is sufficient indication overall of prevention of contamination/co‐intervention |