***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: This paper examines the evidence demonstrating the effectiveness of sealants in high-caries-risk children and discusses the Research Triangle Institute/University of North Carolina 's ( RTI/UNC ) systematic review . The strict RTI/UNC protocol limited the number of sealant studies that could be included . This analysis exp and ed their criteria to permit additional methods of determining caries risk ( for example , past caries experience , less than two pairs of sound first permanent molars available/child in half-mouth design s ) and outcome measures in addition to DMFS ( that is , percent sealant retention , survival rates , cost-effectiveness , changes in salivary S. mutans levels ) . Nine clinical studies with a r and omized , half-mouth , clinical trial design and seven studies with observational study design s were included . There is good evidence that  sealants can be used efficaciously and effectively in high-risk  children as long as the sealant is retained . Sealants are more effective in preventing further caries and providing cost savings in a shorter time span if placed in children who have high rather than low caries risk The aim of the investigation was to evaluate the effect of chlorhexidine gel treatment on  caries development of approximal tooth surfaces  and on salivary counts of Streptococcus mutans .  220 12-year-old schoolchildren , divided into three groups , participated : ( 1 ) chlorhexidine gel group ( n = 72 ) , ( 2 ) placebo gel group ( n = 77 ) , and ( 3 ) control group ( n = 71 ) . The study was carried out double blind with respect to the two gel groups . Group 1 was treated 4 times/year with 1 % chlorhexidine gel and group 2 with a placebo gel . Approximately 1 ml of gel was applied interdentally by means of a flat dental floss . The control group did not receive any gel treatment or flossing . Number of S. mutans in the saliva was estimated on five occasions during the study with the spatula method . After 3 years , the mean approximal caries increment , expressed as new DFS , was 2.50 in the chlorhexidine gel group and 4.30 in the placebo gel group ( p less than 0.05 ) . The corresponding figure in the control group was 5.25 ( p less than 0.001 when compared to group 1 ) . 44 % of the children in the chlorhexidine gel group and 32 % in the placebo gel group did not develop any new approximal caries lesion during the 3-year observation period compared to 18 % in the control group ( group 1 - 3 p less than 0.001 ; group 2 - 3 p less than 0.05 ) . The number of new approximal fillings ( FS ) was 0.24 in the chlorhexidine gel group , 0.75 in the placebo gel group and 0.82 in the control group ( group 1 - 3 p less than 0.01 ; group 2 - 3 p less than 0.05 ) . There was no statistically significant difference between the groups with respect to numbers of S. mutans in saliva . However , there were more individuals with low numbers of S. mutans in the chlorhexidine gel group at the final examination compared to the baseline level ( p less than 0.05 ) 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 % ) Results of a 3-year clinical trial of Delton fissure sealant resin are reported . 41 % of first molar fissures remained fully sealed after 3 years . Significant differences were found between the levels of resin retention produced by the two operators and retention was significantly better on m and ibular molars than on maxillary molars . In a separate group of 11-year-old children 77 % of fissures were full)’sealed after 3 years The effect of daily toothbrushing with 0.5 % chlorhexidine-containing gel for 12 months was evaluated in a double-blind study in 37 dental students . The active gel did not markedly influence plaque formation , gingival conditions , or caries as compared with placebo gel treatment . Salivary bacterial counts were performed on subgroups of six subjects using chlorhexidine gel and on six using placebo gel . No differences in the effect of treatment on the microorganisms studied in the two subgroups could be detected except for S. sanguis . The percentage of this species decrease in the placebo group and increased in the chlorhexidine group . The difference became significant after 2 weeks . A tendency to a greater reduction of S. mutans noted in the chlorhexidine group was most marked in individuals who had high initial counts of this species . The proportion of S. sanguis , which could grow on chlorhexidinei-containing mitis salivarius medium , increased and after 12 months of chlorhexidine treatment averaged 34 % of cultivable S. sanguis compared with 0.002 % prior to treatment . The number of less sensitive S. sanguis decreased in the 12 months following termination of treatment . There was no observed tendency for the selection or proliferation of other streptococci , gram-negative rods , yeasts , or staphylococci 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 The effects of some oral hygiene measures on  Streptococcus mutans and approximal dental caries  were evaluated . One hundred and eighty-seven 13-year-old individuals with high levels of salivary S. mutans ( > 106/mL ) were selected . They were r and omly distributed into three groups . Group I initially received professional mechanical toothcleaning , tongue-scraping , chlorhexidine treatment , and oral hygiene instructions concentrated on the approximal surfaces most colonized by S. mutans . The treatment was given four times with intervals of two days , followed by one single treatment every six months throughout the experimental period . The initial treatment period for group II , also consisting of four visits , included the same oral hygiene instructions as for group 1 . The instructions were repeated every six months . Group III was maintained in the preventive program provided by the local Dental Health Office , based on mechanical plaque control and topical use of fluorides and chlorhexidine at individualized intervals . Group I showed a significant immediate reduction of S. mutans in saliva as well as on approximal tooth surfaces . After six months , there were no differences among the three groups regarding these variables . Compared with baseline , there was a significant reduction of S. mutans in all groups . There was no significant difference in caries progression among the three groups . However , the selected " high-risk " individuals in group I developed 0.25 new manifest caries lesions approximallylyear , compared with 0.27 for all children of the same age group in the area . Seventeen individuals had approximal surfaces with consistently high or consistently low S. mutans levels . Forty-six percent of the surfaces with high values developed new or progressive caries , compared with 2 % of the surfaces with low values A 3-year prospect i ve study was design ed to evaluate sealants in preventing the formation and progression of caries in a young adult military population . United States Navy dentists performed dental examinations on recruits being in-processed at the Naval Training Center , San Diego , California . Contralateral molar pairs ( same arch ) without caries or restorations were selected . Occlusal decalcification and lesions limited to enamel were also eligible , but teeth with proximal decalcification were disqualified . The sample consisted of 860 molar pairs in 529 Navy recruits , each contributing one or two pairs . Required annual dental examinations provided follow-up data , with results being recorded on postcards that were mailed back to the investigator . Yearly response rates were as follows : 1 year , 62.2 % ( 483 molar pairs ) ; 2 year , 47.8 % ( 378 molar pairs ) ; and 3 year , 41.4 % ( 317 molar pairs ) . The response rate for pairs having at least one observation during the 3-year follow-up was 72.6 % ( 563 molar pairs ) , with a caries conversion rate of 1.2 % ( 7 teeth ) on sealed teeth and 5.3 % ( 32 teeth ) on control teeth , yielding 35 discordant molar pairs on 33 recruits ( 30 on control teeth and 5 on sealed teeth ) ( p < 0.0001 ) . These results confirm the efficacy of sealants in significantly reducing the rate caries in a young adult military population The aim of this study was to evaluate the effect of professional flossing with NaF and SnF2 gels on caries development on approximal tooth surfaces . Two-hundred- and -eighty 13-year-old schoolchildren were divided into 3 groups : ( 1 ) NaF ( n = 97 ) , ( 2 ) SnF2 ( n = 85 ) , and ( 3 ) placebo gel group ( n = 98 ) . The investigation was carried out double-blind . The children were treated 4 times a year for 3 years with 1 % NaF gel , 1 % SnF2 gel , or placebo gel . The treatment was carried out by dental nurses and the time required per visit was approximately 10 min . After 3 years , the mean approximal caries increment , including initial caries lesions , was 2.8 in the NaF , 2.4 in the SnF2 , and 4.0 in the placebo gel group ( P < 0.05 for SnF2 vs placebo ) ; a reduction compared to the placebo of 30 % and 39 % in the NaF and SnF2 groups , respectively . Thus , professional flossing with NaF or SnF2 gel carried out 4 times a year may be considered as an interesting caries-preventing method for large-scale application in schoolchildren The aim of this study , performed in Bangkok , was to evaluate the possibility of reducing fissure caries development using an antimicrobial varnish , Cervitec .  Children aged 7 - 8 years and 12 - 13 years , 251 in each age group , with at least 2 sound contra-lateral permanent molars , were selected . A split mouth method was used with one test and one control tooth within the same jaw . At baseline and after two years all children were investigated for DMFS and DMFT . In addition , the size of any cavities was estimated . From 200 children , plaque sample s of test and control occlusal surfaces were collected at baseline and after one year and processed to estimate the number of mutans streptococci . Mutans streptococci in saliva were estimated by the Strip mutans method .  Cervitec varnish , containing 1 per cent chlorhexidine and thymol was applied at baseline , after 3 - 4 and after 8 - 9 months . The results showed that : Cervitec varnish reduced fissure caries development significantly ; the levels of salivary mutans streptococci at baseline were significantly correlated with caries status at baseline and with total caries increment over the two-year period ; caries development in a fissure was significantly correlated to the level of plaque mutans streptococci at that same site ; three months after the last varnish application , a certain reduction of mutans streptococci in plaque could be seen in the test teeth ; comparing the size of the lesions , more large cavities were found in the untreated teeth . It is concluded that varnishes should be considered as further options for prevention of fissure caries , possibly in more individualised programmes or in combination with already established methods A total of 220 children were examined at 4 1/2 years ( 54 months ) after a single application of a pit and fissure sealant . In 110 children , 177 permanent first molars were treated with Nuva-Seal ; and in 110 children , 168 permanent first molars were treated with Delton . Nuva-Seal was completely retained on 35 % of all paired permanent molars , partially retained on  
    Output:
    
Estimates for the number of patients or tooth surfaces needed to treat to prevent a carious event suggest that the effects of these professional treatments are low in patients who are at reduced risk for dental caries .