Hutcheson 2012.

Methods	RCT, split‐mouth study, with 1‐year follow‐up Unit of randomisation: teeth
Participants	Setting: Recruited from 2 dental clinics in Texas, 15 treated in clinic, 25 treated in operating theatre. Single site. Single operator Sample size Number screened: not reported Number eligible: not reported Number randomised: 40 participants (80 teeth) Number analysed: 37 participants (74 teeth) at 6 months, 31 participants (62 teeth) at follow‐up Sex: not reported Age: mean 5.1 years old (range 2.6 to 8) Teeth/lesions: "large carious lesions of similar size approaching the pulp" Inclusion criteria for participants: healthy participants between 2.5 and 8 years old have at least 2 matched, contralateral primary molars in the same arch with large carious lesions of similar size approaching the pulp Inclusion criteria for teeth: large carious lesions of similar size approaching the pulp at least 2 carious surfaces vital and deemed restorable; have previously been treatment planned for a pulpotomy expected to be retained in the mouth for at least 2 years no history of spontaneous or lingering provoked pain, radiographic evidence of internal or external resorption, intraradicular or periapical bone loss, and widening of the periodontal ligament space
Interventions	Intervention: stainless steel crown Control: resin composite multi‐surface, fitted using open sandwich technique. A layer of glass ionomer was used to cover the MTA before resin was applied All participants had MTA pulpotomy All teeth had pulptomies carried out before the crowns or restorations were placed
Outcomes	Outcomes assessed at 6 months and 12 months: gingival inflammation (only appearance of gingivae reported as inflamed or not ‐ not otherwise defined) intact, unchanged margin absence or presence of parulis condition of margin pain 'clinically successful' (not defined) 'radiologically successful' (not defined) plaque index scores gingival index scores (only appearance of gingivae reported as inflamed or not ‐ not otherwise defined)
Source of Funding	No information provided
Declaration of interest	No information provided
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "A tooth in each pair was randomly allocated by coin toss to either the experimental group (MTA/composite) or the control group (MTA/SSC), with the contralateral‐paired tooth assigned to the other treatment"
Allocation concealment (selection bias)	Low risk	Coin toss provided adequate concealment
Blinding of participants and personnel (performance bias) All outcomes	High risk	Comment: No blinding, participant and operator aware of different treatments. Blinding to type of treatment was not possible as the restorations look different. Unclear whether this affected level or quality of care
Blinding of outcome assessment (detection bias) All outcomes	High risk	Quote: "All pre‐ and postoperative radiographs were either digital or digitally scanned and evaluated by 2 blinded, standardized, and calibrated examiners. Coronal portions of the treated teeth were blackened‐out to ensure that the examiners were blinded." Comment: Blinding adequate for radiological findings, but most of the outcomes (clinical and patient‐reported) could not be blinded in the assessment
Incomplete outcome data (attrition bias) All outcomes	High risk	Dropouts were participants who failed to return, despite reminders 31/40 participants (77.5%) available at 12 months, 37/40 (92.5%) available at 6 months Percentage of losses quite large compared to the effect size of the trial
Selective reporting (reporting bias)	Unclear risk	All outcomes outlined in methods section were reported. Provided scale used for radiological ratings Definitions of 'radiologically successful' and 'clinically successful' were not provided
Other bias	Low risk	No other potential biases detected