Tagliaferro 2011.

Study characteristics
Methods	Trial design: parallel‐group study, 6 randomly assigned treatment arms Follow‐up: 24 months
Participants	Location: children were from 2 public schools and lived in a low‐caries‐prevalence city, Brazil Inclusion criteria: children had to have: dmft ≥ 3 or ≥ 1 active cavitated lesion or dmft + DMFT = 0, or a combination of these, and ≥ 2 sound permanent first molars Age at baseline: mean age 7 years Sex: 52% girls, 48% boys Baseline caries: mean dmft index: 4.51 (SD 2.81) for HRS group and 4.28 (SD 2.54) for HRV group. In low‐caries‐risk groups (LRS, LRV groups), dmft + DMFT was 0 Number randomly assigned: 327 children with mean number of occlusal surfaces treated 3.47 (SD 0.80) Numbers of children per group: 57 in HRC group; 57 in HRV group; 55 in HRS group; 53 in LRC group; 52 in LRV group; 53 in LRS group Number evaluated: 268 at 24 months (44 children in HRC group; 48 in HRV group; 47 in HRS group; 42 in LRC group; 43 in LRV group; 44 in LRS group)
Interventions	Comparison: resin‐modified glass ionomer FS vs FV 6 treatment arms Groups 1, 2 and 3 included only high‐caries‐risk children Group 1 (HRC): control group with high‐caries‐risk children receiving OHE Group 2 (HRV): OHE and FV application biannually Group 3 (HRS): OHE and single FS application (resin‐modified glass ionomer cement) Groups 4, 5 and 6 included only low‐caries‐risk children Group 4 (LRC): control group receiving OHE Group 5 (LRV): OHE and FV application biannually Group 6 (LRS): OHE and single FS application (resin‐modified glass ionomer cement) (Only FS and FV groups were considered in this review: groups 2, 3, 5 and 6) Sealants were applied by dentist assisted by dental hygienist in dental clinic (sealants were applied to healthy permanent first molars). Procedure consisted of 4 stages: etching tooth surfaces with 37% phosphoric acid, primer application, ionomer application and finishing gloss application No resealing FV (Duraphat, sodium fluoride) was applied by dentist assisted by dental hygienist, at schools in well‐lit areas, under natural light. Duraphat was applied to occlusal surfaces of sound FPMs. Participants were informed to not brush their teeth or chew food for ≥ 2 hours after treatment, and to consume only soft foods and liquids for 24 hours OHE was carried out by dentist assisted by dental hygienist. Sessions lasting 1 hour were held every 3 months, with talks covering themes such as dental caries, dental plaque and fluoride. Oral hygiene instructions, supervised tooth brushing and dietary counselling were presented to children by means of lectures, videos, educational games and oral quizzes Co‐interventions: 93% of children used fluoridated dentifrice. Mean fluoride concentration in tap water was 0.7 ppm
Outcomes	Primary outcome Sound or carious occlusal surface of FPM: caries increment was stated as mean DMF scores 1 calibrated dentist carried out all examinations. Diagnosis was based on clinical examination, and no radiographs were taken at baseline or at final examinations Secondary outcome Adverse events
Notes	Intra‐examiner reliability: Kappa coefficients 0.95 (caries as cavitated lesions) and 0.90 (caries as cavitated and non‐cavitated lesions) Sealant retention: total sealant loss 16% at 24 months Funding source: FAPESP (São Paulo Research Foundation is an independent public foundation) Caries prevalence of population at study area: mean DMFT 1.32 for 12‐year‐old children
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Additional information was obtained from study authors. Children were systematically allocated to each treatment group as follows: approximately 10 children were taken from each classroom at random by a dental hygienist. The hygienist did not know the caries risk of each child. The hygienist organised the 10 children in a queue at random. (In the queue were also those children not included in the study because they did not fulfil the inclusion criteria of the study; those children were excluded after baseline examination by a dentist.) The examiner (Pardi V) performed the examination of the first child in the queue, and the main researcher (Tagliaferro EP) recorded data on a specific form and classified the child as having high‐ or low‐caries risk, according to pre‐established criteria. After each examination day, record forms were organised according to caries risk (low or high) and sequence of examination. After this, for example, the first examined child of that day classified as having high risk of caries was systematically allocated to the control group, the second to the FV group and the third to the FS group, and successively. Each child was given an ID code to be used over the whole study period. Comment: we graded this domain as low risk of bias because we considered that the randomisation procedure as a whole was unsystematic when noting to which treatment group each child was finally allocated.
Allocation concealment (selection bias)	Low risk	Additional information was obtained from study authors. The main researcher (Tagliaferro) called children for treatments as follows: children allocated to FS groups were brought to a clinical setting, their names and treatment group were checked and Tagliaferro applied sealants, with the help of a dental hygienist. Then, at another time, Tagliaferro went to the school, called the children allocated to FV groups and performed varnish applications. The process of calling only children allocated to FS or FV groups, when sealant applications or varnish applications were performed, respectively, ensured that each child received the intended treatment. Comment: despite incomplete allocation concealment (the same main researcher kept the records and made the applications), the large number of children in each allotted group and the fact that implementation of each treatment was centralised gave the impression that concealment was real.
Blinding of participants and personnel (performance bias) All outcomes	High risk	Blinding not possible as sealants could be seen.
Blinding of outcome assessor (detection bias)	High risk	The presence or absence of the sealant would have revealed the intervention.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Missing data: 8/55 (14.5%) in HRS group, 9/57 (15.8%) in HRV group, 9/53 (17%) in LRS group, 9/52 (17.3%) in LRV group. Quote: "Many individuals had moved out of the schools where the research was conducted, and some refused to take part in the final examination." Comment: although no information was provided to explain reasons for dropouts by group, groups (HRS vs HRV; LRS vs LRV) were assessed as balanced with each other.
Selective reporting (reporting bias)	Low risk	Outcomes reported: caries response. Comment: prespecified outcomes (in methods) were reported in the prespecified way.
Other bias	Low risk	Comparability of groups: Quote: "At baseline, gender, age, use of fluoridated dentifrice, family income, father's and mother's education were not statistically different among the six groups." With regard to clinical variables (dmfs, dmft, DMFS, DMFT, number of occlusal surfaces being treated) at baseline, groups were reported to be balanced. Quote: "Baseline caries experience (dmft + DMFT) was not significantly different between full participants and those lost to follow‐up for HRC, HRV, and HRS groups (in the low caries risk groups, dmft + DMFT was zero)." Comment: detailed description was given on demographic characteristics (sex, age and social class), on baseline caries risk level and on baseline condition of tooth surfaces to be treated, to assess comparability of groups also at 24 months. Groups were assessed as balanced with each other Co‐interventions: All children participated in an oral education programme. 93% of children used fluoridated dentifrice. Comment: in all groups, the same co‐interventions were allowed.