Yang 2008.

Methods	Design: Double blind 4‐arm RCT ‐ 3 arms included in this review Location: Chongqing City, China Study started: December 2004
Participants	Number randomised: 150 Number analysed: 148 Age range: 3 years old at baseline Gender: M 79 / F 71
Interventions	Comparison: FV (2 groups) versus PL Group 1 (n = 37): 0.5% FV (Fluor Protector = 5000 ppm) applied with cotton swab twice after teeth were dried. Children told not to eat or drink for 30 minutes. Treatment was applied every 6 months Group 2 (n = 38): 0.1% FV (Fluor Protector = 1000 ppm) applied with cotton swab twice after teeth were dried. Children told not to eat or drink for 30 minutes. Treatment was applied every 6 months Group 4 (n = 36): Placebo (water) applied with cotton swab twice after teeth were dried. Children told not to eat or drink for 30 minutes. Treatment was applied every 6 months Study duration: 2 years Unclear who applied the interventions, or where the applications took place. There was also a third intervention group (Group 3) 0.5% sodium fluoride which was excluded from the review
Outcomes	Prevalence of caries (CA), dmft, dmfs, number of missing teeth
Notes	Translated by Chunjie Li (September 2012)
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	The authors only described that the participants were allocated randomly without mentioning the methods of randomisation
Allocation concealment (selection bias)	Unclear risk	Not mentioned
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Double blinded trial
Blinding of outcome assessment (detection bias) All outcomes	Low risk	The outcome assessors were blinded to allocated treatment but the details of how this was done are not reported
Incomplete outcome data (attrition bias) All outcomes	Low risk	2 lost to follow‐up: 1 in 0.1% fluoride varnish group and 1 in 0.5% sodium fluoride group. Both of these participants were not included in the analysis. Reason was unclear. Unlikely to have introduced a bias
Selective reporting (reporting bias)	Low risk	Planned outcomes prevalence of caries, dmft, dmfs reported
Baseline characteristics balanced?	Low risk	Prevalence of caries, dmft, dmfs were comparable at baseline
Free of contamination/co‐intervention?	Unclear risk	It was unclear whether participants were exposed to other treatments during the trial

Drop‐out rates based only on groups relevant to review, on relevant follow‐ups, unless otherwise stated. Baseline caries experience averaged among relevant study arms, and based on the study sample analysed at the end of treatment period (final sample), unless otherwise stated. Age range (average age when reported) at the time the study started based on all study participants (or on groups relevant to the review when data were available)
 
 1stm = first permanent molar; 'A' = classified as double‐blind but participants may not be blind (as a 'PL' was used); ADA = American Dental Association; CaF = calcium fluoride; CA = lesions showing loss of enamel continuity that can be recorded clinically (undermined enamel, softened floor/walls) or showing frank cavitation; CCT = controlled clinical trial; CIR = caries incidence rate; cl = clinical examination; deft/s = decayed, extracted and filled primary teeth or surface; dmft/s = decayed, missing (or extracted) and filled primary teeth or surface; D(M)FS/T = decayed, (missing) and filled permanent surfaces or teeth; DR = radiolucency into dentine; E = teeth erupted at baseline; ER = any radiolucency in enamel/enamel‐dentine junction; F = fluoride; FOTI = fibre‐optic transillumination; FV = fluoride varnish treatment; icc = intra‐class correlation coefficient (for inter‐rater reliability); ICC= intra‐cluster correlation coefficient; ICDAS = International Caries Detection and Assessment System; ITT = intention‐to‐treat; M = missing permanent teeth; MD = mesio and distal surfaces; N = numbers; NaF = sodium fluoride; NCA = non‐cavitated enamel lesions visible as white spots or discoloured fissures; NR = not reported; NS = not significant; NT = no treatment; O = occlusal surfaces; OH = oral health; PF = pit and fissure surfaces; PL = placebo varnish; 'PL' = not a true placebo (inactive treatment other than varnish used); postBW = posterior bite‐wing x‐ray assessment; ppm F = parts per million of fluoride; ptc = prior tooth‐cleaning performed with or without a non‐fluoride paste; RCT = randomised controlled trial; SES = socio‐economic status; U = teeth unerupted at baseline; VT = visual‐tactile assessment; xr = radiographic examination.