Carvalho 2010.

Study characteristics
Methods	Design: parallel‐group RCT Recruitment period: not stated Administration setting: schools Country: Brazil Funding source: the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Participants	Number of participants randomised: 232; 232 teeth (rubber dam: 115; cotton rolls: 117) Randomisation unit: participant/tooth Age: 6 to 7 years, mean age 6.3 years Sex: 128 boys, 104 girls Inclusion criteria: aged 6 to 7 years proximal lesions having access to ART hand instruments, with a mesio‐distal maximum dimension of 1 mm and a buccal‐lingual maximum dimension of 2 mm length, measured on the occlusal surface using a periodontal probe lesions with unimpaired adjacent tooth Exclusion criteria: cavitated carious lesions having pulpal involvement, swelling, fistula, or pain Number of participants evaluated: 155 (rubber dam: 72 teeth; cotton rolls: 83 teeth) Withdrawals/loss to follow‐up: 77 children in total. 48 children were unavailable at the time of assessment. 29 children lost their teeth due to exfoliation or extraction
Interventions	Number of groups: 2 Intervention: rubber dam: "For the experiment group, a rubber dam was used, fixed with a clamp on the adjacent distal tooth without local anaesthesia" Control: cotton rolls: "New cotton rolls were placed on both sides of the molar without local anaesthesia" Restorative treatment: proximal ART in primary molars
Outcomes	Outcomes: failure rate/cumulative survival rate of restorations Time points: 6, 12, 18, and 24 months after restoration placement Diagnostic criteria: restorations assessed according to the following criteria: successful treatment: when it was still present and correct or having only a slight wear or defect at the margin < 0.5 mm in depth treatment failures: when the restorations were either completely lost, or were fractured with defects ≥ 0.5 mm in depth, had secondary caries, or inflammation of the pulp lost to follow‐up: when the children who were not found at the time of assessment, or when the teeth were lost to exfoliation or extraction
Notes	Adverse events: not stated No details on sample size or power calculation provided The survival/failure rate was not consistent with the number of restorations considered as success or failure presented in table 1 of the report. We were unable to use the data in the analysis
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "Each child was individually allocated into a group by the use of generated random numbers, and no restrictions were considered" Comment: method stated and appropriate
Allocation concealment (selection bias)	Unclear risk	Quote: "Each child was individually allocated into a group by the use of generated random numbers, and no restrictions were considered. The group in charge of making the restorations or those who assessed the restorations did not have access to the randomizations procedure. All children were allocated into the respective group before the restorations were made" Comment: sequence allocation was not adequately described
Blinding of participants and personnel (performance bias) All outcomes	High risk	Comment: the operators and the participants could not be blinded
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Quote: "These examiners were blinded to the exposure categories. In other words, at the time of examination of the restoration, the examiners did not know to which group the child belonged to" Comment: examiners were blinded
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Quote: "Throughout the study, a total of 48 (20.7%) children were considered as lost to follow‐up. Others eventually lost their teeth due to exfoliation or extraction. Due to such reasons, a total of 77 restorations (33.2%) were censored (lost to follow‐up), where 34 (14.7%) were from the control group and 43 (18.5%) from the rubber dam group (χ2 [Chi2] = 1.82; df [degrees of freedom] = 1; P = 0.18)" Comment: loss to follow‐up was high (overall 33.2%) and reasons for loss to follow‐up (20.7%) were not explicitly explained
Selective reporting (reporting bias)	High risk	Comment: survival/failure rate was not consistent with the number of restorations considered as success or failure presented in table 1. We were unable to use the data in the analysis
Other bias	Low risk	Comment: groups at baseline (age, gender, jaw, molar and operator) comparable