Ueno 2012

Methods	Study design: controlled before‐and‐after study Conducted in: Tokyo Unit of randomisation: grade Unit of analysis: individual Setting: senior high school in the “Encourage School” programme Funded by: not disclosed Duration of the study: 1 year
Participants	Inclusion criteria: not reported Exclusion criteria: not reported Age at baseline: 15 to 17 years N (controls baseline): 135 N (controls follow‐up): 135 N (interventions baseline): 163 N (interventions follow‐up): 163 Recruitment: All students in grade 1 acted as the intervention group. All students in grade 2 acted as the control group Gender Intervention: male = 79, female = 84 Control: male = 65, female = 70
Interventions	Intervention Two 100‐minute sessions of oral health education. Sessions contained detailed explanations of cause, treatment and prevention of malodour. Visual materials such as photographs, figures and dental models were used Control: routine school oral health education Duration of intervention: 1 year
Outcomes	Decayed teeth Gingivitis
Implementation related factors	Theoretical basis: not reported Resources for implementation: not reported Who delivered the intervention: research staff and dentists 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: ‘Encourage School’ is a school programme specifically targeted at students with lower levels of academic and social achievement Economic evaluation: not reported
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	High risk	Two grades from a school were selected. All grade 1 students formed the intervention group, and all grade 2 students served as the control group
Allocation concealment (selection bias)	Unclear risk	Unclear
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Unclear
Selective reporting (reporting bias)	Unclear risk	Unclear
Other bias	High risk	Intervention was delivered at the same school, and it is possible for allocated units (grades) to become contaminated
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Unclear
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Unclear