Frencken 2001

Methods	Study design: quasi‐experimental Conducted in: Zimbabwe Unit of randomisation: school Unit of analysis: individual Setting: sub‐Saharan Africa, Mutoko District in Mashonaland East Province Funded by: unclear in terms of support/funding. However, the study stated, "Assistance for the study was provided by the following institutions: the Ministry of Health, Dental Department of Zimbabwe, Provincial Hospital Mashonaland East, District Hospital in Mutoko, District Education Office in Mutoko, headmaster and teachers of all participating schools in Mutoko District" Duration of the study: 3.5 years (1992 to 1996)
Participants	Inclusion criteria: grade 2 and grade 4 children, children from schools accessible by vehicle that had representatives attending the oral health education (OHE7) programme Exclusion criteria: not reported Age at baseline: grade 2, mean age = 8.1 years; grade 4, mean age = 10.4 years N (controls baseline): 488 (229 grade 2, 259 grade 4) N (controls follow‐up): 309 (133 grade 2, 176 grade 4) N (interventions baseline): 477 (221 grade 2, 256 grade 4) N (interventions follow‐up): 297 (135 grade 2, 162 grade 4) Recruitment: school Gender: at baseline, 439 boys, 526 girls
Interventions	Intervention: oral health education workshop and information pack administered to 1 teacher and the headmaster of each school Control: not attending workshops Duration of intervention: 1.5 days
Outcomes	Plaque accumulation and caries increment
Implementation related factors	Theoretical basis: behaviour change Resources for implementation: workshop on oral health and rehabilitation, teacher time, toothbrush and chewing sticks, fluoridated toothpaste, oral health instruction booklet and OHE lessons Who delivered the intervention: ministry of health staff PROGRESS categories assessed at baseline: not reported 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)	High risk	A total of 9 rural schools were selected and were proportionately divided between those having attended the workshop (4 experimental) and those not attending the workshop (5 control)
Allocation concealment (selection bias)	Unclear risk	No concealment
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Unclear
Selective reporting (reporting bias)	Unclear risk	Unclear
Other bias	Unclear risk	Unclear
Blinding of participants and personnel (performance bias) All outcomes	High risk	No blinding of personnel. Researchers were involved in outcome measurement. “The evaluation could not be done blind, as the evaluators were involved in designing the study”
Blinding of outcome assessment (detection bias) All outcomes	High risk	No blinding