Lu 1987.
| Methods | Trial design: 3‐armed, double‐blind, active‐controlled and stratified RCT Location: USA Number of centres: not reported. Area surrounding Portland, Oregon Recruitment period: study commenced in/before 1983 |
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| Participants | Inclusion criteria: not reported Exclusion criteria: orthodontic appliances; unsuitable medical history (examiner‐determined) Baseline caries: 4.01 DMFS (Gp A: 3.89 DMFS (SE 0.160); Gp B: 4.08 DMFS (SE 0.184); Gp C: 4.07 DMFS (SE 0.186). Baseline characteristics (DMFS, DMFT) "balanced" Age at baseline (years): range 7 to 15 years, mean 10.48 years (Gp A: 10.22; Gp B: 10.18; Gp C: 10.50). Baseline characteristic (age) "balanced" Sex: 2273 F:2221 M (Gp A: 339 F:364 M; Gp B: 334 F:339 M; Gp C: 345 F:334 M). Baseline characteristic (sex) "balanced" Any other details of important prognostic factors: background exposure to fluoride: community water supply < 0.3 ppm F Number randomised: 4494 (Gp A: 1491; Gp B: 1503; Gp C: 1500) Number evaluated: 2055 at 3 years (present at final assessment. Gp A: 703; Gp B: 673; Gp C: 679) Attrition: 55% dropout (for all study groups combined) after 3 years (study duration = 3 years). Reasons for attrition not reported; any differential group losses not assessable |
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| Interventions |
Comparison: FT versus FT (3 groups)a
Gp A (n = 1491): NaF 1100 ppm F; abrasive system: silica; home use/unsupervised: daily frequency assumed
Gp B (n = 1503): SMFP 2800 ppm F; abrasive system: silica; home use/unsupervised: daily frequency assumed Gp C (n = 1500): NaF 2800 ppm F; abrasive system: silica; home use/unsupervised: daily frequency assumed |
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| Outcomes | Primary: 3‐year DMFS increment ‐ cl + xr; DMFT increment (at 1, 2 and 3 years) Secondary: not assessed Assessments irrelevant to this review's scope: n/a Follow‐up duration: 3 years | |
| Notes | Adverse effects: not reported Funding source: grant from Procter & Gamble Declarations/conflicts of interest: 2 (OP Sturzenberger, RW Lehnhoff) of 5 authors employed by the manufacturer, Procter & Gamble. Remaining authors employed by Oregon Health Sciences University. 2 additional Procter & Gamble employees (BW Bollmer, WE Cooley ‐ neither are authors) undertook the study's statistical analyses and data presentation Data handling by review authors: aGps B + C versus Gp A combined in analysis Other information of note: analysis of covariance undertaken. Clinical examination by 1 examiner |
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| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Unclear risk | Quote: " ... assigned at random.." |
| Allocation concealment (selection bias) | Unclear risk | Comment: insufficient information |
| Blinding (performance bias and detection bias) All outcomes | Low risk | Quotes: " double‐blind clinical study" and "Toothbrushes and assigned dentifrices labelled with the subjects name and unique identification number were supplied by the study's sponsor in plain white 2,7 oz tubes every 6 months" |
| Incomplete outcome data (attrition bias) All outcomes | High risk | Comment: no reasons for attrition reported and 3‐year withdrawals are high 53%, 55%, 55% in the 1100, 2800 SMFP, 2800 NaF groups |
| Selective reporting (reporting bias) | Low risk | Comment: DMFT, DMFS increments over 3 years |
| Baseline characteristics balanced? | Low risk | Comment: balance of age, sex, DMFS, DMFT at baseline. Adjusted analysis (analysis of covariance) |
| Free of contamination/co‐intervention? | Unclear risk | Comment: toothpaste given at school in named tube for home use for all the family. Contamination unlikely |