Koch 1990.
| Methods | Trial design: 5‐armed, double‐blind, active‐controlled and stratified RCT Location: Iceland Number of centres: 7 elementary schools, Reykjavik Recruitment period: study commenced in 1983 | |
| Participants | Inclusion criteria: not reported Exclusion criteria: not reported Baseline caries: 9.9 DFS (Gp A: 9.9 DMFS (SD 7.0); Gp B: 10.6 DMFS (SD 7.2); Gp C: 9.7 DMFS (SD 6.5); Gp D: 9.3 DMFS (SD 6.4); Gp E: 10.2 DMFS (SD 7.4). Baseline characteristic (DFS) "balanced" Age at baseline (years): range 11 to 12 years (group distribution reported by year of birth 1971/2). Baseline characteristic (age) "balanced" Sex: 587 F:559 M (Gp A: 113 F:116 M; Gp B: 114 F:115 M; Gp C: 113 F:116 M; Gp D: 133 F:101 M; Gp E: 114 F:111 M). Baseline characteristics (sex) "balanced" Any other details of important prognostic factors: background exposure to fluoride in community water supply < 0.1 ppm F Number randomised: 1161 (Gp A: 231; Gp B: 232; Gp C: 231; Gp D: 237; Gp E: 230) Number evaluated: 1035 at 3 years (present at final assessment. Gp A: 203; Gp B: 209; Gp C: 209; Gp D: 211; Gp E: 203) Attrition: 10.9% dropout (for all study groups combined) after 3 years (study duration = 3 years). Reasons for attrition: relocation, compliance, others; no differential group losses | |
| Interventions |
Comparison: FT versus FT (5 groups)a
Gp A (n = 231): 250 ppm NaF (no anti‐calculus agent); abrasive system: silica; home use/unsupervised, daily frequency assumed Gp B (n = 232): 940 ppm F SMFP (no anti‐calculus agent); abrasive system: CaHPO42H2O; home use/unsupervised, daily frequency assumed Gp C (n = 231): 970 ppm F NaF (no anti‐calculus agent); abrasive system: silica; home use/unsupervised, daily frequency assumed Gp D (n = 237): 980 ppm F NaF (anti‐calculus agent AHBP); abrasive system: silica; home use/unsupervised, daily frequency assumed Gp E (n = 230): 940 ppm F NaF (anti‐calculus agent AHBP); abrasive system: silica; home use/unsupervised, daily frequency assumed |
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| Outcomes | Primary: 3‐year net DFS increment cl + xr; DFS increment by surface; DFT increment; new lesions only and restorations (at 3 years) Secondary: adverse effects Assessments irrelevant to this review's scope: gingival health (gingival bleeding index); compliance Follow‐up duration: 3 years | |
| Notes | Adverse effects: "Adverse experiences were only noted [sic] one occasion when a child, belonging to [Gp D], claimed an allergic reaction to the dentifrice and was withdrawn from the study" Funding source: Henkel KGaA, manufacturer of experimental toothpaste Declarations/conflicts of interest: manufacturer engaged in funding the study, administration support of study: "The authors gratefully acknowledge... the financial, administrative and scientific support of Henkel KGaA, Düsseldorf, FRG" Data handling by review authors: a1000 ppm F groups combined for analysis Gps B + C versus Gp A. Groups with anti‐calculus agents excluded from analysis (Gps D and E) Other information of note: clinical examinations performed by 2 examiners. Prior to each exam, both dentists examined 20 of their assigned children at random who were re‐examined at least 1 day later to gauge consistency. ICC of at least 0.75 for acceptable reliability but exact values not stated | |
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Unclear risk | Quote: " ...randomly assigned to one of five treatment groups" |
| Allocation concealment (selection bias) | Unclear risk | Comment: insufficient information |
| Blinding (performance bias and detection bias) All outcomes | Low risk | Quotes: "...unsupervised double‐blind study" and "...dentifrices were purchased and refilled in laminated tubes to ensure dentifrices were identical" |
| Incomplete outcome data (attrition bias) All outcomes | Unclear risk | Comment: reasons for attrition stated. Attrition rate was low after 3 years, 11% overall and similar in all toothpaste groups. Query compliance as reason for withdrawal and this negates ITT analysis, although only 23/1146 (2%) withdrew or were withdrawn for this reason |
| Selective reporting (reporting bias) | Low risk | Comment: results reported DFT, DFS, on different surface types |
| Baseline characteristics balanced? | Low risk | Comment: balance of age, sex, DFS |
| Free of contamination/co‐intervention? | Unclear risk | Comment: insufficient information |