Atieh 2008.

Methods	RCT with 2‐year follow‐up Unit of randomisation: teeth
Participants	Setting: Dammam Medical Center (DMC) in the Eastern Province of Saudi Arabia between January 2003 and January 2004. Single site. Single operator Sample size Number screened: 535 children Number eligible: 126 (39 refused) Number randomised: 87 participants (160 teeth), 47 treated for more than one tooth Number analysed: at 24 months, 65 teeth with fillings (81%) and 68 teeth with crowns (85%) Age: 4–7 years, mean 5.5 years; SD 1.1 Sex: 41 boys and 46 girls Teeth/lesions: not reported Inclusion criteria for participants: acceptable oral hygiene i.e. plaque index score of 20% or less had a behavioural rating score of 3 or 4 on the Frankl scale at least 1 restorable primary molar tooth Inclusion criteria for teeth: restorable primary molar with cariously exposed pulp Exclusion criteria for teeth: symptomatic teeth with spontaneous pain, swelling, and tenderness to percussion, pathological mobility, and preoperative radiographic pathology (bitewing radiographs)
Interventions	Intervention: PMCs Control: modified open‐sandwich technique using resin‐modified glass ionomer cement or composite resin restorations All teeth had pulpotomies carried out before the crowns or restorations were placed. All participants were given oral hygiene instructions after treatment
Outcomes	Outcomes were assessed at 6, 12, 18 and 24 months ± 2 weeks, or until tooth exfoliation or participant dropout and included: retention of restored teeth (survival analysis censoring fillings that dropped out, natural exfoliation, or replacement of restorations) clinical failure: spontaneous pain, fistula, soft tissue swelling, pathological tooth mobility, partial fracture or total loss of RMGIC/CRRs, crown loss following cement failure, or perforation of occlusal surface as a result of wear modified United States Public Health Service (USPHS) criteria in terms of marginal integrity, gingival health, secondary caries, proximal contact, and occlusion gingival health ‐ whether a site bled on gentle probing
Source of Funding	No information provided
Declaration of interest	No information provided
Notes	All teeth had pulptotomies carried out before the interventions Follow‐up numbers: initially: fillings 80 (100%), crowns 80 (100%) 6 months: fillings 75 (94%), crowns 77 (96%) 12 months: fillings 73 (91%), crowns 74 (93%) 18 months: fillings 69 (86%), crowns 71 (89%) 24 months: fillings 65 (81%), crowns 68 (85%)
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "Randomization was generated through a computer program where each primary molar had an equal chance to be assigned to either SSC or RMGIC/CRR"
Allocation concealment (selection bias)	Unclear risk	No description of allocation concealment method provided
Blinding of participants and personnel (performance bias) All outcomes	High risk	Quote: "Both the participants and the dentist could not be blinded to the intervention because of the different appearance of the two types of restoration" Comment: no blinding, patient and operator aware of different treatments, as restorations looked different. Unclear whether this affected level or quality of care
Blinding of outcome assessment (detection bias) All outcomes	High risk	Quote: "At each follow‐up visit, the children were examined by the same dentist in a dental chair with a dental mirror and a probe" Comment: Participant and operator were aware of different treatments, which could affect judgement of subjective outcomes
Incomplete outcome data (attrition bias) All outcomes	High risk	Participants who had bleeding during pulpotomy were excluded from analysis (total of 6: 2 teeth from the SSC group, 4 from the control group) In addition, 4 participants in each group were lost to follow‐up after 24 months. Only 68/80 from the SSC and 65/80 from the control group were analysed for clinical outcome Not all exclusions/losses were fully accounted for
Selective reporting (reporting bias)	High risk	No access to protocol Statistical analysis did not take clustering into account, and insufficient information was reported to allow for an analysis for the year 2 data. Data could not be analysed in a meta‐analysis
Other bias	Low risk	No other potential biases detected