***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: Background Dental caries remains one of the most common chronic diseases of adolescents . In Australia there have been few epidemiological studies of the caries experience of adolescents with most surveys focusing on children . The New South Wales ( NSW ) Teen Dental Survey 2010 is the second major survey undertaken by the Centre for Oral Health Strategy . The survey is part of a more systematic and efficient approach to support State and Local Health District dental service planning and will also be used for National reporting purpose s. Methods Data for the NSW Teen Dental Survey were collected in 2010 from a r and om sample of Year 9 secondary school students aged 14 to 15 years from metropolitan and non-metropolitan schools under the jurisdiction of the NSW Department of Education and Training , the Catholic Education Commission and Independent Schools in New South Wales . Nineteen calibrated examiners performed 1269 clinical examinations at a total of 84 secondary schools across NSW . The survey was accompanied by a question naire looking at oral health related behaviours , risk factors and the usage of the Medicare Teen Dental Plan . Results 175 schools were contacted , with 84 ( 48 % ) accepting the invitation to participate in the study . A total of 5,357 student consent forms and parent information packages were sent out and 1,256 students were examined ; leading to a student participation rate of 23 % . The survey reported a mean DMFT for 14 and 15 year olds of 1.2 and it was identified that 45.4 % of students had an experience of dental caries . Major variations in caries experience reported occurred by remoteness , water fluoridation status , socio-economic status and household income levels . Conclusions The NSW Teen Dental Survey provided state-wide data that will contribute to the national picture on adolescent oral health . The mean DMFT score of 1.2 is similar to the national caries experience data for this age group from the Australian Child Dental Health Survey in 2009 Fluoride , a trace element with anticariogenic benefit may either occur naturally or be added to drinking water sources . This study aim ed at determining the fluoride level of the different drinking water sources in Ibadan , Oyo State , Nigeria and to relate this with the caries experience of secondary school children in the city . Sixteen sample s of the drinking water sources from various locations in the five local government areas of the city were analysed for fluoride concentration . The locations were selected around the vicinities of the secondary schools used for caries study . Nine hundred and fifty five students aged 15 - 19 years r and omly selected from eleven secondary schools in Ibadan metropolis were examined for dental caries over a period of 4 - 5 months . Only teeth with obvious cavitations were recorded as being carious using the WHO st and ard method . Teeth grossly covered with calculus and third molars were excluded . No radiograph was taken . The fluoride level of the different water sources was between 0.02 and 0.03 ppm . Forty-four ( 4.6 % ) of the children had dental caries . There was no statistically significant difference between either DMFT and gender ( t = 0.67 , p = 0.91 ) or DMFT and age ( F = 1.488 , p = 0.224 ) . However , females had a slightly higher mean DMFT than males and the highest mean DMFT ( 2.67 + /- 1.15 ) was found among the 19-year-old children . Twenty-three ( 52.3 % ) of the students with caries had only one carious tooth while only two had four carious teeth each . In conclusion , both the fluoride level and caries prevalence were low The objective of the present study was to determine the caries experience of schoolchildren aged 7–12 years from the Southeast area of São Paulo State , Brazil , in 1998 , according to town size and fluoridation status . Data for this cross‐sectional study were based on the data bank from the Epidemiological Survey of São Paulo State provided by the State Health Department . After stratification by fluoridation status and town size , 29 towns were r and omly selected to represent the Southeast area of São Paulo State , Brazil , and a total of 13,480 schoolchildren were r and omly selected for this study . Calibrated dentists performed clinical examinations according to the WHO criteria . Caries experience and prevalence were significantly lower in fluori date d areas ( 1.9 DMFT , 2.1 dmft , 20 % caries free ) than in non‐fluori date d areas ( 2.4 DMFT , 2.4 dmft , 13 % caries free ) . According to town size , DMFT and caries prevalence were significantly higher in small towns ( 2.3 DMFT , 13 % caries free ) , followed by medium‐sized ( 2.1 DMFT , 17 % caries free ) and large cities ( 1.6 DMFT , 27 % caries free ) . Among 12‐year‐old children  , caries prevalence was predominantly moderate or high in small and medium‐sized municipalities , whereas in large cities it was moderate or low . The results suggest that water fluoridation is an essential public health measure and that town size may affect caries distribution in the Southeast area of São Paulo State BACKGROUND The purpose of the study was to investigate the relationship between fluoride ions in drinking water and the incidence of  dental fluorosis in some endemic areas of Bongo District , Ghana . METHOD Two hundred children were r and omly selected from various homes and taken through a question naire . Their teeth were examined for the detection of dental fluorosis using the Dean 's specific index . Sample s of their permanent sources of water were taken for the determination of soluble fluoride levels by SPADNS spectrophotometric method . RESULTS The study revealed that the incidence of dental fluorosis among the children in the main Bongo township was 63.0 % , whereas villages outside the township recorded less than 10.0 % . The respondents from the various communities had similar age group , educational background , sources of drinking water , oral hygiene habits and usage of oral health products , p-value > 0.05 . However , there were statistically significant differences in the cases of dental fluorosis and fluoride ions among the communities , p-value < 0.05 . The fluoride ion concentration in the Bongo township was above the WHO requirement of 1.50 ppm , whereas the nearby villages showed acceptable fluoride levels . Statistically , there was no significant relationship between the presence of dental fluorosis and the other characteristics , except the age group and fluoride ion concentration of the area . CONCLUSION These findings strongly support the association between the dental fluorosis and the high fluoride levels in the underground water of Bongo community . Therefore , policy makers need to consider an alternative source of drinking water for the area This study assesses the effect on enamel formation of the use of fluoride toothpaste in a fluori date d area . The prevalence of enamel hypoplasia in 251 9 - 10-year-old children born and raised in a fluori date d city ( Birmingham ) was compared with that in 319 similar children born and raised in a non-fluori date d city ( Leeds ) . Observer bias was eliminated by the use of a new photographic technique , enabling colour slides of both groups to be assessed together in a r and om order . Scoring was done using both the Jackson-Al-Alousi ( J-A ) index , which is design ed to record nonspecific hypoplasias and the Tooth Surface Index of Fluorosis ( TSIF ) . Both were compared to the results from conventional clinical recording using the J-A index . The results showed that the photographic method was highly reproducible and more sensitive than conventional recording and showed a higher level of mild fluorosis in the fluori date d area . However , no evidence of an increase in the higher grade s of fluorosis was found . It is concluded that the use of fluoride toothpaste by young children in fluori date d areas is unlikely to produce aesthetically unacceptable levels of enamel Objective To assess the effects of provided fluoride-safe drinking-water for the prevention and control of endemic fluorosis in China . Design A national cross-sectional study in China . Setting In 1985 , r and omly selected villages in 27 provinces ( or cities and municipalities ) in 5 geographic areas all over China . Participants Involved 81 786 children aged from 8 to 12 and 594 698 adults aged over 16 . Main outcome measure The prevalence of dental fluorosis and clinical skeletal fluorosis , the fluoride concentrations in the drinking-water in study villages and in the urine of subjects . Results The study showed that in the villages where the drinking-water fluoride concentrations were higher than the government st and ard of 1.2 mg/l , but no fluoride-safe drinking-water supply scheme was provided ( FNB areas ) , the prevalence rate and index of dental fluorosis in children , and prevalence rate of clinical skeletal fluorosis in adults were all significantly higher than those in the historical endemic fluorosis villages after the fluoride-safe drinking-water were provided ( FSB areas ) . Additionally , the prevalence rate of dental fluorosis as well as clinical skeletal fluorosis , and the concentration of fluoride in urine were found increased with the increase of fluoride concentration in drinking-water , with significant positive correlations in the FNB areas . While , the prevalence rate of dental fluorosis and clinical skeletal fluorosis in different age groups and their degrees of prevalence were significantly lower in the FSB areas than those in the FNB areas . Conclusions The provision of fluoride-safe drinking-water supply schemes had significant effects on the prevention and control of dental fluorosis and skeletal fluorosis . The study also indicated that the dental and skeletal fluorosis is still prevailing in the high-fluoride drinking-water areas in China OBJECTIVES This paper presents data on the prevalence of primary tooth fluorosis among children residing in Iowa , and the relationships between fluorosis prevalence and selected measures of fluoride exposures . METHODS Children in the study cohort were followed prospect ively during the first year of life . This study assessed their home water fluoride concentrations and use of fluoride dentifrice or dietary fluoride supplements . A total of 637 children ( 320 females and 317 males ) were examined for fluorosis using a modification of the TSIF index at age 4 1/2 to 5 years , with 90.4 percent having intact primary dentitions . RESULTS 74 children ( 11.6 % ) had  fluorosis  present on one or more of their primary teeth , and 71 children ( 11.1 % ) had two or more teeth affected . Nearly all fluorosis was mild , with the primary second molar teeth most commonly affected . Fluorosis was significantly associated with higher water fluoride concentration , but not with the use of dentifrice or fluoride supplements . CONCLUSIONS The results of this study show that primary tooth fluorosis is relatively uncommon , but is most frequently seen on the posterior teeth , particularly the primary second molars , which form at later stages of development . This finding suggests that primary tooth fluorosis is mostly a postnatal phenomenon , and is associated with higher water fluoride levels The purpose of this study was to evaluate the difference in dental caries and fluorosis prevalence in 936 r and omly selected life-long residents selected from public and private schools in Trois-Rivières ( 1.0 ppm F in 1987 ) and Sherbrooke ( less than 0.1 ppm F ) , Que . , Canada . Students , 11 - 17 years of age , were examined for dental caries using the National Institute for Dental Research criteria and for dental fluorosis using the Tooth Surface Index of Fluorosis . Because of an inconsistent fluoridation history in Trois-Rivières , comparisons were carried out between two age strata : students 11 - 14 years of age who consumed for a longer duration suboptimally fluori date d water than those in the second stratum : students 15 - 17 years of age . Only public school students , 15 - 17 years of age , from Trois-Rivières had significantly lower mean filled surface and decayed , missing , and filled tooth surface ( DMFS ) scores ( 28 and 24 % , respectively ) than similar students in Sherbrooke . Among private school students , differences were not found , except in the youngest age group in Sherbrooke who had significantly lower mean DMFS than similar students from Trois-Rivières . The prevalence of fluorosis was 45.6 % and 58.0 % in Trois-Rivières public and private schools , respectively , and 31.1 % and 30.1 % in Sherbrooke public and private schools , respectively . The use of fluoride tablets was significantly associated with fluorosis . This study showed that water fluoridation benefitted students from public schools and that the risk factors for dental fluorosis were the use of fluori date d water and fluoride tablets OBJECTIVES To compare dental caries levels of schoolchildren stratified in different social classes whose domestic water supply had been fluori date d since birth ( Dublin ) with those living in an area where fluori date d salt was available ( Freiburg ) . METHODS A representative , r and om sample of twelve-year-old children was examined and dental caries was recorded using World Health Organization criteria . RESULTS A total of 699 twelve-year-old children were examined , 377 were children in Dublin and 322 in Freiburg . In Dublin the mean decayed , missing , and filled permanent teeth ( DMFT ) was 0.80 and in Freiburg it was 0.69 . An examination of the distribution of the DMFT score revealed that its distribution is highly positively skewed . For this reason this study provides summary analyses based on medians and inter-quartile range and nonparametric rank sum tests . In both cities caries levels of children in social class 1 ( highest ) were considerably lower when compared with the other social classes regardless of the fluoride intervention model 
    Output:
    
There is very little contemporary evidence , meeting the review 's inclusion criteria , that has evaluated the effectiveness of water fluoridation for the prevention of caries .
The available data come predominantly from studies conducted prior to 1975 , and indicate that water fluoridation is effective at reducing caries levels in both deciduous and permanent dentition in children .
There is insufficient evidence to determine whether water fluoridation results in a change in disparities in caries levels across SES .
We did not identify any evidence , meeting the review 's inclusion criteria , to determine the effectiveness of water fluoridation for preventing caries in adults .
There is insufficient information to determine the effect on caries levels of stopping water fluoridation programmes .
There is a significant association between dental fluorosis ( of aesthetic concern or all levels of dental fluorosis ) and fluoride level .