***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: PURPOSE This study compares four chemotherapeutic regimens used for inhibiting carious lesion progression : silver nitrate ( AgNO3 ) ; silver fluoride/stannous fluoride ( AgF/SnF2 ) ; silver diammine fluoride ( SDF ) ; and chlorhexidine ( CHX ) . METHODS For this study , a bacterial model system containing Mutans streptococci ( MS ) and Lactobacilli casei ( L ) was used to generate carious lesions on 85 extracted sound permanent third molars which were r and omly assigned to four test groups and one control group . At week two , the four treatment regimens were applied to the lesions ( one treatment per test group ) . RESULTS Six weeks later , lesions treated with a single AgF/SnF2 or AgNO3 application demonstrated 29 % and 19 % less lesion progression , respectively , than did the control group ( P < 0.05 ) . SDF and CHX did not differ significantly from the control . CONCLUSION AgF/SnF2 and AgNO3 may be useful in slowing down carious lesion depth progression The recording of multiple interval-censored failure times is common in dental research . Modeling multilevel data has been a difficult task . This paper aims to use the Bayesian approach to analyze a set of multilevel clustered interval-censored data from a clinical study to investigate the effectiveness of silver diamine fluoride and sodium fluoride varnish in arresting active dentin caries in Chinese pre-school children . The time to arrest dentin caries on a surface was measured . A three-level r and om-effects Weibull regression model was used . Analysis was performed with WinBUGS . Results revealed a strong positive correlation ( 0.596 ) among the caries lesions ’ arrest times on different surfaces from the same child . The software WinBUGS made the above complicated estimation simple . In conclusion , the annual application of silver diamine fluoride on caries lesions , and caries removal before the application , were found to shorten the arrest time We hypothesized that the six-monthly application of silver diamine fluoride ( SDF ) can arrest the development of caries in the deciduous dentition of six-year-old schoolchildren and prevent caries in their first permanent molars . A prospect i ve controlled clinical trial was conducted on the efficacy of a 38 % SDF solution for caries reduction .  Four hundred and twenty-five six-year-old children were divided into two groups : One group received SDF solution in primary canines and molars and first permanent molars every 6 mos for 36 mos . The second group served as controls . The 36-month follow-up was completed by 373 children . The mean number of new decayed surfaces appearing in primary teeth during the study was 0.29 in the SDF group vs. 1.43 in controls . The mean of new decayed surfaces in first permanent molars was 0.37 in the SDF group vs. 1.06 in controls . The SDF solution was found to be effective for caries reduction in primary teeth and first permanent molars in schoolchildren Over a period of 18 months the following non-traumatic methods of treating dental caries in deciduous teeth were compared : application of stannous fluoride ( SnF2 ) ; application of SnF2 and silver diamine fluoride ( SDF ) ; application of SnF2 , SDF , minimal cavity preparation and use of composite resin ; minimal cavity preparation and composite resin only ; no treatment .  Caries progressed in only 5 per cent of the SDF/SnF2 group and 11 per cent of the composite resin group . The results indicate that it may be possible to treat carious lesions in a non-traumatic way using minimally prepared cavities and composite resin . This could significantly alter the restorative care of deciduous molars and it may be reasonable to speculate that the technique could also have important implication s for use in the permanent dentition This study aim ed to evaluate the risk-benefit balance of several fluoride exposures . Fluoride exposure history of r and omly selected children was collected for calculation of exposure to fluori date d water , toothpaste , and other fluoride sources . We evaluated the risk-benefit balance of fluoride exposure by comparing dental fluorosis on maxillary central incisors , recorded at the time of the study with the use of the Thylstrup and Fejerskov Index , and deciduous caries experience , recorded at age six years , of the same group of South Australian children who were from 8 to 13 years old in 2002–03 .  Population Attributable Risk for fluorosis and Population Prevented Fraction for caries were estimated . Fluorosis prevalence was found to be 11.3 % ; caries prevalence , 32.3 % ; mean dmfs , 1.57 ( SD 3.3 ) . Exposure to fluori date d water was positively associated with fluorosis , but was negatively associated with caries . Using 1000-ppm-F toothpaste ( compared with 400- to 550-ppm-F toothpaste ) and eating/licking toothpaste were associated with higher risk of fluorosis without additional benefit in caries protection . Evaluation of the risk-benefit balance of fluoride exposure provides evidence to assist in the formulation of appropriate guidelines for fluoride use Dental caries in Chinese pre-school children is common , and restorative treatment is not readily available . This prospect i ve controlled clinical trial investigated the effectiveness of topical fluoride applications in arresting dentin caries . We divided 375 children ( aged 3 - 5 yrs ) with carious upper anterior teeth into five groups . Children in the first and second groups received annual applications of silver diamine fluoride solution ( 44,800 ppm F ) . NaF varnish ( 22,600 ppm F ) was applied every three months onto the lesions of children in the third and fourth groups . For children in the first and third groups , soft carious tissues were removed prior to fluoride application . The fifth group was the control . We followed 341 children for 18 months . The mean numbers of new caries surfaces in the five groups were 0.4 , 0.4 , 0.8 , 0.6 , and 1.2 , respectively ( p = 0.001 ) . The respective mean numbers of arrested carious tooth surfaces were 2.8 , 3.0 , 1.7 , 1.5 , and 1.0 ( p < 0.001 ) 
    Output:
    
These promising results suggest that SDF is more effective than fluoride varnish , and may be a valuable caries-preventive intervention .
As well , the availability of a safe , effective , efficient , and equitable caries-preventive agent appears to meet the criteria of both the WHO Millennium Goals and the US Institute of Medicine ’s criteria for 21st century medical care