van Palenstein 1997

Methods	Study design: quasi‐experimental, controlled before‐and‐after study Conducted in: Tanzania Unit of randomisation: school Unit of analysis: individuals clustered by school Setting: Morogoro Funded by: "The research was supported by grants from the Netherlands through NUFFIC and from Denmark through DANIDA" Duration of the study: 3 years
Participants	Inclusion criteria: not reported Exclusion criteria: not reported Age at baseline: not reported N (controls baseline): 200 N (controls follow‐up): 122 N (interventions baseline): 400 N (interventions follow‐up): 309 Recruitment: through schools Gender: not reported
Interventions	Intervention: school‐based oral health education (OHE) programme One‐day workshop administered to the head teacher and to 1 teacher at each participating school Included: information on good oral hygiene practice, demonstrations of good oral hygiene behaviour and implementation of regular supervised toothbrushing sessions at school. Teachers then undertook weekly toothbrushing sessions and monthly lessons about causes and prevention of caries and gingivitis. These lessons incorporated traditional methods of schooling in Tanzania such as use of songs, dance and drama Control: schools where representatives did not attend the OHE workshop Duration of intervention: 1‐day workshop, then ongoing throughout duration of grade 4
Outcomes	Dental caries, plaque, calculus, gingival bleeding
Implementation related factors	Theoretical basis: social determinants of health, socio‐ecological model Resources for implementation: workshop, training, staff time Who delivered the intervention: teachers 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: specifically designed low‐budget OHE programme for application in semi industrialised Tanzania Economic evaluation: The school‐based OHE programme was designed as a low‐budget programme. Study authors inferred that the cost‐effectiveness of the intervention was questionable
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Process of randomisation not reported
Allocation concealment (selection bias)	Unclear risk	First 2 randomly selected schools were assigned as participating schools for assessment of clinical outcome effects (n = 8). The third school randomly selected from each quarter section was assigned as a non‐participating school to serve as control (n = 4)
Incomplete outcome data (attrition bias) All outcomes	Low risk	Of a total of 400 children at baseline in participating schools, 91 dropped out during the course of the study. In control schools, 200 children were examined at baseline. One control school (M = 50) had to be withdrawn from the study because the school had started a similar OHE programme on its own initiative. Of the remaining 150 control children at baseline, 28 dropped out. Most dropouts were caused by transfer to other schools. Some were due to illness or occurred because students were moved back to a lower grade
Selective reporting (reporting bias)	Low risk	Published report presents all expected outcomes of interest to the review
Other bias	Unclear risk	Unclear
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Unclear
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Unclear, but article states, “the examiner did not know which schools were the controls”