Samaranayake 1989.

Study characteristics
Methods	Trial design: CCT Location: University of Glasgow, Dental Hospital and School, UK Setting: 12 feet by 15 feet in the pedodontic clinic Language: English Number of centres: 1 Study period: not mentioned Funding source: not mentioned Study protocol: not available
Participants	Age: 10 to 14 years Total number of participants: 20 Inclusion criteria: children who required restorative procedures Exclusion criteria: not mentioned Number of participants: 20 (10 per group) Confounding factors: not found Selection bias: not found Method of blinding: not available Number evaluated (withdrawals/missing participants): 20 (none)
Interventions	Comparison: rubber dam versus no rubber dam Intervention: Group name: with rubber dam Number of intervention groups: 1 Number in intervention group: 10 Description of intervention: 10 children in the intervention group underwent restorative procedures with rubber dam. Any co‐interventions: no Comparator: Group name: without rubber dam Number of control groups: 1 Number in control group: 10 Description of control: 10 children in the control group underwent restorative procedures without rubber dam.
Outcomes	Outcome name: reduction in contamination of aerosols (measured at 1 metre, 2 metres, 3 metres from head rest) Outcome measurement: CFU Effect estimate: mean + SE Key conclusions: results indicate that the use of a rubber dam perioperatively is associated with significantly higher bacterial aerosol levels and bacterial reduction was greatest 1 metre from head rest.
Notes	Study author to be contacted for: method of randomisation, allocation concealment, blinding and study protocol. Study is 31 years old – missing data unlikely to be traceable. We could not contact the authors as their e‐mail details were not available.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	High risk	Details on confounding factors not found
Allocation concealment (selection bias)	High risk	Details of selection process not available
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Blinding is not possible. However, participants and personnel will not be able to alter their behaviour even if they know the received intervention.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	It is not clear if the CFU were manually counted or any automated colony counters were used – there is subjectivity if manually counted.
Incomplete outcome data (attrition bias) All outcomes	Low risk	No dropouts
Selective reporting (reporting bias)	Unclear risk	We are not sure of reporting selective outcomes as there is no protocol available
Other bias	Low risk	None