Antonson 2012.

Methods	Trial design: split‐mouth design, sealant material randomly assigned among tooth pair Year the study started: no information provided Follow‐up: 24 months
Participants	Location: USA Inclusion criteria: Children had to have bilateral partially erupted permanent first molars that were free of restorations, hypoplasia, fracture or cracks; operculum coverage of at least one‐fourth and up to one‐half of the occlusal surface. Teeth with an operculum that covered more than one‐half of the occlusal surface were excluded. One dentist examined the molars with a calibrated laser fluorescence device (DIAGNOdent) for the absence of occlusal caries; teeth for which DIAGNOdent reading was higher than 20 were excluded (thus enamel lesions accepted). Age at baseline: 5 to 9 years Gender: not stated Baseline caries: not stated but children at high risk of developing caries were identified according to socioeconomic background and included in the study. Number randomly assigned: 39 children with 39 tooth pairs Number evaluated: 27 children with 27 tooth pairs
Interventions	Comparison: glass ionomer sealant versus resin‐based sealant Tooth pair: occlusal surface of 1 tooth sealed with glass ionomer sealant (light cured GC Fuji Triage White); occlusal surface of the other tooth of the tooth pair sealed with light cured resin‐based sealant Delton Plus+. Sealants were applied to partially erupted occlusal surfaces of permanent first molars by a dentist. No re‐sealing Co‐interventions: no information provided
Outcomes	Sound or carious occlusal surface of molar Examinations were performed with the use of a mirror, blunt explorer and air stream
Notes	Calibrated investigators (2 investigators) but there is no information on the kappa‐coefficients. Funding source: Nova Southeastern University President's Faculty Research and Development grant 335381 and GC America, Alsip, Ill
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "We used a coin toss to assign sealants randomly to quadrants"
Allocation concealment (selection bias)	Low risk	Comment: Although the information of allocation concealment was incomplete, this domain was graded low risk of bias because we saw that in split‐mouth studies the risk of selection bias is in any case insignificant.
Blinding? (Outcome assessors)	High risk	Quote: "Two calibrated investigators who were not involved with the treatment procedures evaluated the sealants". Comment: Although blinding of outcome assessor was indicated, this domain was graded as having high risk of bias because we saw that blinding of outcome assessor in clinical trials of this nature cannot be performed, as outcome assessor can discriminate between materials after follow‐up.
Incomplete outcome data? (Caries efficacy outcomes)	High risk	Missing data: 12/39 (31%) children after 24 months. Quote: "At the 24‐month recall visit, 12 participants were absent, mainly because of relocations". Comment: Missing data rate more than 25%
Selective reporting (reporting bias)	Low risk	Outcomes reported: incidence of dentinal carious lesion on treated occlusal surfaces of molars, retention Comment: Pre‐specified caries outcomes (in methods) were reported in the pre‐specified way
Free of other bias? Comparability of the groups	Low risk	Comment: Split‐mouth design with similar conditions during the follow‐up
Free of other bias? Co‐interventions	Unclear risk	No information provided