O'Mullane 1997.
| Methods | Trial design: 4‐armed, double‐blind, stratified RCT Location: UK Number of centres: single, 2‐surgery mobile dental unit, attending secondary schools in Clwyd and Gwynedd, North Wales, UK Recruitment period: study began 1989 | |
| Participants | Inclusion criteria: not reported Exclusion criteria: caries‐free children, dentally immature children, or fitted with a fixed orthodontic appliance Baseline caries: 4.9 DMFS (Gp A: 5.11 DMFS (SD 4.15); Gp B: 4.69 DMFS (SD 3.78); Gp C: 5.10 (SD 4.15); Gp D: 4.74 (SD3.71)) (evaluated attendees only). Baseline characteristics (DMFS) "very good" Age at baseline (years): range 11 to 12 years, mean not reported (group distribution not reported) Sex: 1754 F:1713 M (Gp A: 854 F:867 M; Gp B: 900 F:846 M; Gp C: 874 F:856 M; Gp D: 800 F:857 M) (evaluated attendees only (clinical only)) Any other details of important prognostic factors: background exposure to fluoride: none reported, although Anglesey resident children were excluded as water supply was fluoridated Number randomised: 4196 (group distribution not reported) Number evaluated: 3467 at 3 years (available at final clinical examination; 1942 for clinical and radio examinations) (evaluated attendees only). (Groups relevant to review: Gp A: 491; Gp B: 474; Gp C: 477; Gp D: 500) Attrition: 17% dropout (for all study groups combined) after 3 years (study duration = 3 years). Reasons for attrition: only changing area of residence given; "this did not affect the balance between/among the toothpaste groups" | |
| Interventions |
Comparison: FT (4 groups)a
Gp A (n = evaluated 491): 1000 ppm NaF; abrasive system: silica; home use/unsupervised, daily frequency assumed
Gp B (n = evaluated 474): 1500 pppm NaF; abrasive system: silica; home use/unsupervised, daily frequency assumed Gp C (n = evaluated 477): 1000 ppm NaF + 3% TMP; abrasive system: silica; home use/unsupervised, daily frequency assumed Gp D (n = evaluated 500): 1500 pppm NaF + 3% TMP; abrasive system: silica; home use/unsupervised, daily frequency assumed |
|
| Outcomes | Primary: 3‐year DMFS increment cl (VT, FOTI) + xr; DMFS increment cl (at 3 years) Secondary: none assessed Assessments irrelevant to this review's scope: compliance; rinsing method Follow‐up duration: 3 years | |
| Notes | Adverse effects: not reported Funding source: grant from Unilever Dental Research Declarations/conflicts of interest: none stated Data handling by review authors: afactorial design, SMFP and TMP Other information of note: 2 clinical examiners re‐examined 5% of their allocated and 5% of children allocated to the other clinician. Intra‐ and inter‐reliability > 0.93 | |
| Risk of bias | ||
| Bias | Authors' judgement | Support for judgement |
| Random sequence generation (selection bias) | Unclear risk | Quotes: "... prospective participants allocated sequential identification numbers" and "... children randomly allocated to 1 of 4 toothpaste groups based on 4 stratifying factors" |
| Allocation concealment (selection bias) | Unclear risk | Comment: insufficient information |
| Blinding (performance bias and detection bias) All outcomes | Low risk | Quotes: "... double‐blind" and "radiographs were read by clinical examiners without reference to the clinical findings" |
| Incomplete outcome data (attrition bias) All outcomes | Low risk | 3467/4196 children available for analysis. Attrition mainly due to moving away from area; did not alter balance between groups Comment: reasonable dropout rate for duration of study; unlikely to be due to intervention |
| Selective reporting (reporting bias) | Low risk | DMFS increment. Clinical and radiographic assessments |
| Baseline characteristics balanced? | Low risk | Comment: no statistically significant difference in DMFS score at baseline for NaF only paste (8% lower in 1500 ppm group for combined NaF/NaF + TMP groups) |
| Free of contamination/co‐intervention? | Low risk | Comment: no apparent cause for concern regarding contamination. Sufficient toothpaste supplied for whole family so contamination unlikely |