D'Cruz 2013

Methods	Study design: randomised controlled trial Conducted in: schools in Bangalore, India Unit of randomisation: schools Unit of analysis: individual Setting: school Funded by: not disclosed Duration of the study: 9 months
Participants	Inclusion criteria: school children 13 to 15 years of age, those willing to participate Exclusion criteria: school children with systemic diseases and conditions and under medication, those undergoing orthodontic treatment Age at baseline: 9 months N (control group) baseline: 300; follow‐up: 284 N (intervention group 1) baseline:150; follow‐up: 140 N (intervention group 2) baseline: 150; follow‐up: 143 Recruitment: Experimental and control schools were selected through a 2‐stage random sampling method using a table of random numbers Gender I group 1: male = 47.5%, female = 52.5% I group 2: male = 47.6%; female = 52.4% C: male = 51.8%, female = 48.2%
Interventions	Interventions Intervention group 1: oral health education delivered through a PowerPoint presentation Intervention group 2: oral health education delivered through a PowerPoint presentation combined with demonstration of toothbrushing using study models Control: no intervention Duration of intervention: not reported
Outcomes	Gingival index Plaque index
Implementation related factors	Theoretical basis: not reported Resources for implementation: not reported Who delivered the intervention: unclear PROGRESS categories assessed at baseline: gender PROGRESS categories analysed at outcome: not reported Outcomes related to harms/unintended effects: not reported Intervention included strategies to address diversity or disadvantage: not reported Economic evaluation: not reported
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Table of random numbers was used
Allocation concealment (selection bias)	Unclear risk	Unclear
Incomplete outcome data (attrition bias) All outcomes	Low risk	Attrition was only 6% in experimental group 1, 4.7% in experimental group 2 and 5.3% in the control group
Selective reporting (reporting bias)	Unclear risk	Unclear
Other bias	Unclear risk	Unclear
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Study is described as double‐blind, but information related to blinding is unclear
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Unclear