Saied‐Moallemi 2009.

Methods	Study design: Cluster randomised controlled trial (4 clusters) Conducted in: Tehran Unit of randomisation: Schools Unit of analysis: Schools Funded by: Iran Centre for Dental Research (ICDR)
Participants	Inclusion criteria: Attending third‐grade class in a boys and girls school within Tehran Exclusion criteria: None reported Age at baseline: 9 year olds Gender: Mixed boys (n = 224) and girls (n = 233) (2 boys and 2 girls schools in each group) Number of participants randomised: Total Intervention n = 340 (Class‐work group (n = 115) 4 schools; Parental‐aid group (n = 114) 4 schools; Combined group (n = 111) 4 schools); Control group (n = 117) 4 schools Number of participants evaluated: Total Intervention n = 331 (Class‐work group (n = 110) 4 schools; Parental‐aid group (n = 112) 4 schools; Combined group (n = 109) 4 schools); Control group (n = 116) 4 schools
Interventions	Comparison: Compare the effectiveness in promoting children's gingival health of 3 school‐based interventions versus a no intervention control group Class‐work group: Delivered in class under supervision of school health counsellors during 3 to 4 sessions in 1 month (30‐45 minutes each) by means of 7 various illustrative puzzles printed on A4 sheets, used as learning tools, including oral health messages guiding children to twice‐daily toothbrushing, use of fluoride toothpaste and understanding of cariogenic food. After the completion of each puzzle, the health counsellor explained the oral health message that it conveyed. Intervention delivered by teachers and school health counsellors. Details of the interventions were not explained to the children Parental‐aid group: Provided at home by parents without giving any additional instructions on oral health at school. 2‐page A4‐size oral health leaflet and a brushing diary/chart together were delivered by the health counsellors to the children to take home. Leaflet contained comprehensive oral health information on the aetiology of common oral diseases – gingival disease and dental caries – and their associations with general diseases and quality of life. Emphasizing the preventability of oral diseases and ways to keep the mouth healthy by recommending twice‐daily toothbrushing, use of fluoride toothpaste and restricting sugary snacking. Modelling role of parents was underlined Combined group: Intervention carried out in schools and at home through combination of both groups above Control: No intervention in control group only clinical exam and parental questionnaire Duration of intervention: 3 months Post‐intervention: 3 months Duration of follow‐up: None stated Behavioural or psychological component: School 7 BCTs; home 5 BCTs Dental: Promoting children's gingival health Nutrition: Puzzles about healthy foods and posters on the issues around sugary snacks
Outcomes	Plaque: Modification of a plaque index (PI). Dental plaque was recorded as no plaque, plaque on gingival margins only, and plaque elsewhere, with scores correspondingly 0, 1, and 2. Acceptable oral hygiene and healthy gingiva were also reported in each group Mothers completed self administered questionnaires at baseline concerning demographic variables (90% reported)
Notes	Design by/Pilot work: Unclear how the intervention was designed and if any pilot work was conducted Power calculation: "To detect a 25% reduction in the scores of dental plaque and gingival bleeding with a = 0.05 (2 sided), power = 80%, 1%‐3% attrition, means of 11.00 (SD = 1.4) for plaque and of 4.00 (SD = 1.3) for bleeding, the intra‐cluster correlation coefficients being 0.08 and 0.12, respectively, 1 school/arm with 29 children examined in each school was required. To allow the use of normal distribution critical values and possible effects by gender 16 schools (4 schools/arm) were enrolled" (p 521)
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	"The clusters were not randomly assigned". Method of sequence generation not described
Allocation concealment (selection bias)	Unclear risk	Not reported
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Details of the interventions were not explained to the children
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Dental examiner were blinded to group assignment for post‐intervention but baseline examinations was carried out by a separate examiner who was one of the authors, but it was unclear if they were blinded. Calibration between examiners was carried out
Incomplete outcome data (attrition bias) All outcomes	Low risk	Numbers excluded from analysis are low and similar in each group. Reasons for missing outcome data unlikely to be related to true outcome
Selective reporting (reporting bias)	High risk	Post‐intervention data were not reported clearly only baseline data were presented in the tables
Other bias	Low risk	No other sources of bias identified