Naylor 1979.
| Methods | Trial design: 3‐armed, double‐blind, placebo‐controlled, stratified RCT Location: UK Number of centres: not reported. Secondary schools in Winchester, Andover and Basingstoke across Hampshire Recruitment period: study began in 1973 | |
| Participants | Inclusion criteria: not reported Exclusion criteria: absence from school at baseline examination Baseline caries: 7.9 DFS (groups relevant to review: 7.9 DFS (Gp A: 8.00 DFS (SD 5.92); Gp B: 7.78 DFS (SD 5.36))). Baseline characteristics (SAR, TAR, DFS, DFT) "balanced" Age at baseline (years): range 11 to 12 years (groups relevant to review: Gp A: 11.94 years (SD 0.3); Gp B: 11.94 years (SD 0.3)). Baseline characteristic (age) "balanced" Sex: 465 F:479 M (groups relevant to review: 313 F:312 M (Gp A: 160 F:159 M; Gp B: 153 F:153 M)) (assessed participants only) Any other details of important prognostic factors: background exposure to fluoride in community water supply < 0.3 ppm F Number randomised: 1183 (groups distribution not reported) Number evaluated: 944 at 3 years (available at final examination) (groups relevant to review: 625 (Gp A: 319; Gp B: 306)) Attrition: 20% dropout (for all study groups combined) after 3 years (study duration = 3 years). Reasons for attrition not reported; any differential group losses not assessable | |
| Interventions | Comparison: FTa versus PL Gp A (n = 319 evaluated): SMFP 1000 ppm F; abrasive system: Ca carbonate; home use/unsupervised, daily frequency assumed Gp B (n = 306 evaluated): placebo; abrasive system: Ca carbonate; home use/unsupervised, daily frequency assumed | |
| Outcomes | Primary: 3‐year DFS increment ‐ (E) (CA) cl + (ER) xr; O‐BL‐DFS; MD‐DFS; DFT; DFT (U); CIR (at 3 years) Secondary: none assessed Assessments irrelevant to this review's scope: subjective oral hygiene rating assessment Follow‐up duration: 3 years | |
| Notes | Adverse effects: not reported Funding source: partial funding by Beecham Group Ltd. Other source of funds not reported Declarations/conflicts of interest: not reported, authors employed by Guy's Hospital, London and Forsyth Dental Center, Massachusetts Data handling by review authors: aCa glycerophosphate/SMFP toothpaste group not considered (additional non‐F active agent used in this group only) Other information of note: clinical (VT) caries assessment (FOTI used) by 2 examiners (independently), diagnostic threshold = CA; state of tooth eruption included = E/U. Radiographic assessment (2 postBW) by 2 examiners (independently), diagnostic threshold = ER. Results of 1 examiner chosen (findings consistent throughout) | |
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Low risk | Quote: "The subjects were stratified according to age and sex and assigned by means of a table of random numbers to dentifrice groups" |
| Allocation concealment (selection bias) | Unclear risk | No information provided |
| Blinding (performance bias and detection bias) All outcomes | Low risk | Quotes: "... at no time during the study was the identity of these groups known to the examiners or anyone directly associated with the study" and ".. control dentifrice same as for group 1 but without the fluoride" 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: 20.2% (239/1183) in 3 years (for all 3 groups). Dropout by group: not reported. Reasons for losses: not reported Comment: numbers lost were not unduly high for the length of follow‐up. It is unclear if there were any differential losses, and if reasons for missing outcome data are acceptable and balanced. Caries data used in the analysis pertain to participants present at final examinations |
| Selective reporting (reporting bias) | Low risk | Outcomes reported:
DFS increment ‐ (E) (CA) cl + (ER) xr, reported at 3 years follow‐up
DFT
DFT (U)
O‐BL‐DFS
MD‐DFS
CIR 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:
DFS: 7.36 FT, 7.62 PL mean age: 11.94 (0.30) FT, 11.94 (0.30) PL TAR: 17.6 FT, 17.66 PL DFT: 4.99 FT, 5.08 PL SAR: 95.84 FT, 96.21 PL Comment: initial caries appears balanced |
| Free of contamination/co‐intervention? | Low risk | Quote: "Sufficient supplies were also left for all other members of the family" Comment: there is sufficient indication overall of prevention of contamination/co‐intervention |