Charbeneau 1979.

Methods	Trial design: split‐mouth design, treatment tooth randomly assigned among tooth pair Year the study started: 1973 Follow‐up: 48 months
Participants	Location: USA, children were from 2 schools Inclusion criteria: children had to have at least 1 contralateral pair of caries ‐ or restoration‐free permanent first molar. Diagnosis made clinically by mirror and explorer. Age at baseline: 5 to 8 years Gender: no information provided Baseline caries: no information provided Number randomly assigned: 143 children with 229 tooth pairs Number evaluated: 186 tooth pairs at 24 months, 193 tooth pairs at 36 months, 185 tooth pairs at 48 months Drop‐out rate: 26/143 (18%) children at 48 months (information on numbers of children at all follow‐ups not stated).
Interventions	Comparison: resin‐based sealant versus no sealant Tooth pair: occlusal surface of 1 tooth sealed with resin‐based sealant (second generation resin‐based autopolymerised sealant (Kerr Pit and Fissure)); occlusal surface of the other tooth of the tooth pair served as a control without sealant.The occlusal surface was considered acceptable for treatment if the occlusal mesial surface of maxillary molar was sound, even though occlusal distal surface was carious or filled. No resealing. All procedures conducted in a 2‐chair mobile dental van, which provided optimal physical facilities. Co‐interventions: no information provided
Outcomes	Sound or carious or restored occlusal surface of molar and sealant retention status. Outcomes assessed by 2 dentists
Notes	Inter‐examiner agreement: 91.2% for tooth status (caries or restoration) at 36 months (2 evaluators) Funding source: no identified funding source (authors were from university)
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "Sealant was applied to the isolated test tooth that was selected by using a table of random numbers." Comment: Adequate sequence generation
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	Comment: this domain was graded as having high risk of bias because we saw that blinding of outcome assessors in clinical trials of this nature cannot be performed, as sealants are visible
Incomplete outcome data? (Caries efficacy outcomes)	Low risk	Missing data: 26/143 (18%) children at 48 months. Comment: Drop‐out rate under 25%
Selective reporting (reporting bias)	Low risk	Outcomes reported: Caries response and sealant retention. Comment: Pre‐specified outcomes (in methods) were reported in pre‐specified way
Free of other bias? Comparability of the groups	Low risk	Comment: Split‐mouth design with the same baseline diagnosis of the teeth within a tooth pair (caries‐free surfaces)
Free of other bias? Co‐interventions	Unclear risk	No information provided