Dhar 2012.

Methods	Trial design: split‐mouth design, teeth were randomly selected to be sealed with or without tooth preparation with a glass ionomer or resin‐based sealant Year the study started: no information provided Follow‐up: 24 months
Participants	Location: India, children represented low socio‐economic backgrounds Inclusion criteria: children had to have 4 erupted, non‐carious permanent first molars. Clinical examinations carried out by a single examiner with a dental assistant. Age at baseline: 6 to 10 years Gender: not detailed Baseline caries: caries prevalence for the studied age group in the area was 63.2% and DMFT of 2.60 (additional information obtained from the author). Number randomly assigned: 25 children with 50 tooth pairs Number evaluated: 25 children with 50 tooth pairs
Interventions	Comparison: glass ionomer sealant versus resin‐based sealant Tooth pair: occlusal surface of 1 tooth sealed with glass ionomer‐based sealant (GC Fuji Ionomer VII light pink)); occlusal surface of the other tooth of the tooth pair sealed with fluoride releasing resin‐based sealant (Clinpro pink) No resealing Each of the 25 children had their 4 permanent molars subjected randomly to the 4 techniques: a) glass ionomer‐based sealant with tooth preparation, b) glass ionomer‐based sealant without tooth preparation, c) resin‐based sealant with tooth preparation, and d) resin‐based sealant without tooth preparation. The preparation technique involved widening and deepening the fissures with a one quarter round bur, with a slow‐speed handpiece. Sealants were applied by 1 dentist with a dental assistant. Anesthesia and rubber dam application were used to obtain maximum standardisation of sealant placement. Applications and recall examinations were carried out in a dental clinic setting. Co‐interventions: all children were given oral hygiene instructions which was reinforced at each visit, and all children used regularly fluoridated toothpaste. None of the subjects were on fluoride supplements. Tap water was not fluoridated (additional information obtained from the author)
Outcomes	Sound or carious occlusal surface of molar and sealant retention status Data concerning teeth without surface preparation were included in review analyses. Data concerning teeth with surface preparation were reported separately because data were seen not to be comparable with data from the other studies (only this study included teeth with surface preparation). Outcomes were assessed by 1 dentist with the help of a dental assistant. Caries was detected visually for opacity, defects at the margin, or softness by an explorer
Notes	Inter‐examiner reproducibility: kappa statistic 1.0 Funding source: no identified funding source
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "Teeth were randomly selected to be sealed with or without tooth preparation with a glass ionomer or resin‐based sealant." Additional information obtained from the author: Randomisation was performed using the 'chit system'. A 'chit' was a piece of paper on which 1 of the treatment options was written‐ this paper was then carefully folded to conceal the written part. 4 such chits were made with different treatment options. Since the indications for all the 4 treatment options were the same, the provider randomly picked up a chit and provided the sealant type and technique mentioned for the tooth in question. He recorded what treatment was done for each tooth on the record sheet for that patient.
Allocation concealment (selection bias)	Low risk	The treatment provider randomly picked up a 'chit' and provided the sealant type and technique mentioned for the tooth in question. Information obtained from the author. Comment: The description gives an impression that the treatment was performed immediately (sealants were applied by 1 dentist with a dental assistant).
Blinding? (Outcome assessors)	High risk	Quote: "The examiner was blinded to the technique used, but not to the material used since the materials had different colours." Additional information obtained from the author: All the identifiers were concealed and the record forms of selected children were assigned a code number by a person other than the provider/examiner. The examiner evaluated each patient and filled out a new coded record sheet provided for that patient by the helper. The examiner could not be blinded for the type of sealants since 1 of the sealants used is coloured but did not have any information on whether the tooth was prepared or not. After evaluation was completed all the record sheets were collected by the helper and stapled together with the patient's previous record sheet. A new sheet was filled out by the examiner at each follow‐up visit.
Incomplete outcome data? (Caries efficacy outcomes)	Low risk	Missing data rate: 0%.
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	Quote: "Non‐carious molars included." Comment: This domain was graded low risk of bias because we saw that both surfaces within a tooth pair will eventually be in equal risk for caries because of the long follow‐up time (regardless of whether the diagnosis was sound surface or surface with enamel lesion)
Free of other bias? Co‐interventions	Low risk	Additional information obtained from the author: All children were given oral hygiene instructions which was reinforced at each visit. All children used regularly fluoridated toothpaste. None of the subjects were on fluoride supplements. Tap water was not fluoridated. Comment: This domain was graded low risk of bias because no other co‐interventions than fluoridated toothpaste were included in the protocol