***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Abstract The aim of the study was to measure the fluoride ( F ) concentration in plaque after a single topical application of different fluoride varnishes with contrasting levels of F. Thirty adolescents ( 12–17 years ) with fixed orthodontic appliances were r and omly assigned to one of three groups : Bifluoride ( 6 % F ) , Duraphat ( 2.23 % F ) and Fluor Protector ( 0.1 % F ) . The varnishes were applied after professional cleaning in one upper quadrant , leaving the opposite quadrant untreated according to the split-mouth technique . Pooled plaque sample s from each quadrant were collected at baseline and 3 days , 7 days and 30 days after the varnish treatment , and fluoride was analysed by microdiffusion . All fluoride varnishes increased the fluoride concentration in plaque compared with baseline , and the mean values varied between 23 and 138 ng F/mg after 3 days , depending on varnish F concentration . Compared with the control quadrant , statistically significant elevations were recorded for Bifluoride after 3 days and 7 days and Duraphat after 3 days , while no significant differences were revealed in the Fluor Protector group . The fluoride concentration in plaque was back to baseline levels for all participants in the Duraphat group after 7 days , while some individuals in the Bifluoride and Fluor Protector groups still registered slightly increased levels after 30 days . The results suggest that fluoride varnish treatments result ed in elevated fluoride levels in plaque adjacent to fixed orthodontic appliances for a period of up to 1 week , although different patterns was disclosed for the various br and The present study compares visible-light Delton with Duraphat fluoride varnish for the prevention of occlusal caries in permanent first molars . A clinical trial was carried out in three groups of 6 - 8-yr-old schoolchildren : a sealant group ( 100 children ) , in which Delton light-polymerized fissure sealant was applied to permanent first molars ; a varnish group ( 98 children ) , in which Duraphat was applied to permanent first molars ; and a control group ( 116 children ) .  Replacement ( sealant ) and reapplication ( varnish ) was carried out every 6 months . Percent effectiveness at 24 months ( percentage of saving from caries taking molars as analysis unit ) for those molars initially healthy and with complete occlusal eruption was analyzed . 272 , 252 and 238 molars met the inclusion criteria in the control , varnish and sealant groups , respectively . Of these , 45.2 % , 28.2 % and 10.5 % developed caries after 24 months . The effectiveness was greater in the sealed molars than in the varnished molars ( 62.7 % ) The objective of this study was to compare Delton visible-light fissure sealant with Duraphat fluoride varnish in the prevention of occlusal caries in permanent first molars . A 48-month clinical trial was carried out in three groups of 6- to 8-year-old schoolchildren : a sealant group ( 104 children ) , in which Delton was used ; a varnish group ( 112 children ) , in which Duraphat was used ; and a control group ( 128 children ) . Sealant or varnish was applied to all sound permanent first molars , according to group . Replacement ( sealant ) and reapplication ( varnish ) was carried out every 6 months . A survival analysis was used to describe the molar failures over time in the three groups . A Cox proportional hazards regression model was built to test the influence of group on molar failure . The median survival times were 28.6 months for the control molars and more than 48 months for both sealed and varnished molars . The Cox model indicated a hazard ratio of 0.177 for the sealant vs control comparison , 0.463 for varnish vs control and 0.382 for sealant vs varnish OBJECTIVE The aim of this study was to determine the separate effects of dental sealants and fluoride varnish on  dental  caries in fissured and nonfissured surfaces of permanent first molars . METHODS A clinical trial was conducted with three groups of 6- to 8-year-old schoolchildren : a sealant group ( n = 100 ) , in which  Delton was applied to first molars ; a varnish group ( n = 98 ) , in which  Duraphat was applied to first molars  ;  and a control group ( n = 116 ) , which  had no intervention as part of the study .  Absolute and percent caries reductions were compared at 24 months . RESULTS Compared to the controls , sealants result ed in a 68 percent and 87 percent reduction on fissured and nonfissured surfaces , respectively . The corresponding figures for varnish were 38 percent and 66 percent . CONCLUSION Sealant and fluoride varnish are effective in preventing caries in both fissured and nonfissured surface 
    Output:
    
There was some evidence on the superiority of pit and fissure sealants over fluoride varnish application in the prevention of occlusal decays .