Muhler 1970.
| Methods | Trial design: 3‐armed, double‐blind, placebo‐controlled, stratified RCT Location: USA Number of centres: not reported Recruitment period: study began in/before 1967 | |
| Participants | Inclusion criteria: not reported Exclusion criteria: not reported Baseline caries: 10.3 DMFS (Gp A: 10.71 DMFS (SE 0.746); Gp B: 9.72 DMFS (SE 0.585)). Baseline characteristic (DMFS) with some imbalance Age at baseline (years): range 5 to 17 years, mean 10 years (Gp A: 10.33 years; Gp B: 10.16 years). Baseline characteristic (age) with some imbalance Sex: 426 F:336 M (groups relevant to review: 284 F:226 M (Gp A: 140 F:106 M; Gp B: 144 F:120 M)). Baseline characteristic (sex) with some imbalance Any other details of important prognostic factors: background exposure to fluoride: data not available for fluoridation status of site Number randomised: 762 (groups relevant to review: n = 510 (Gp A: 246; Gp B: 264) Number evaluated: at 1 year (available at final examination) (groups relevant to review: n = 436 (Gp A: 201; Gp B: 235)) Attrition: 15% dropout after 1 year (study duration = 1 year). Reasons for attrition not reported; differential group losses | |
| Interventions | Comparison: FTa versus PL Gp A (n = 246): SnF2 1000 ppm F; abrasive system: Ca pyrophosphate; home use/unsupervised, daily frequency assumed Gp B (n = 264): placebo; abrasive system: Ca pyrophosphate; home use/unsupervised, daily frequency assumed | |
| Outcomes | Primary: 1‐year DMFS increment ‐ cl + xr; DMFT (at 6 months and 1 year) Secondary: not assessed Assessments irrelevant to this review's scope: n/a Follow‐up duration: 1 year | |
| Notes | Adverse effects: not reported Funding source: partially funded by Procter & Gamble. Other source of funds not reported Declarations/conflicts of interest: sole author employed by Indiana University Data handling by review authors: aNa N‐lauroyl sarcosinate/SMFP toothpaste group not considered (additional non‐F active agent used in this group only) Other information of note: clinical (VT) caries assessment by 1 examiner, diagnostic threshold not reported. Radiographic assessment (5 to 7 BW) by 1 examiner, diagnostic threshold not reported. State of tooth eruption included not reported. Diagnostic errors not reported | |
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Low risk | Quote: "... children were divided into 3 groups by separation of age, sex and DMFS, followed by randomization with restrictions to balance by three's within each cell" Comment: block randomisation performed |
| Allocation concealment (selection bias) | Unclear risk | No information provided |
| Blinding (performance bias and detection bias) All outcomes | Low risk | Quotes: "The first group of children received placebo dentifrice...." "All dentifrices were furnished in plain white tubes with appropriate codes to identify the products" and "At no time during the study did the examiner, the recorder or the clinical staff have any knowledge of the patient being examined or the product being used" 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: 15% in 1 year. Dropout by group: 45/246 FT, 29/264 PL. Reasons for losses: not reported Comment: numbers lost were not unduly high for the length of follow‐up, but there is differential loss between groups (18% FT, 11% PL). 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. Group losses unlikely to be related to intervention |
| Selective reporting (reporting bias) | Low risk | Outcomes reported:
DMFS increment ‐ cl + xr, reported at 6 months and 1 year follow‐ups
DMFT 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:
DMFS: 10.71 FT, 9.72 PL age: 10.33 FT, 10.16 PL gender: 106 M, 140 F FT; 120 M, 144 F PL Comment: initial caries appears balanced between groups |
| Free of contamination/co‐intervention? | Low risk | Quote: "All the children were given new toothbrushes and sufficient dentifrice for their personal use and for their entire family" Comment: there is sufficient indication overall of prevention of contamination/co‐intervention |