Caries prevalence and length of residency in fluoridated and non-fluoridated communities

The caries experience of grade 6 Canadian schoolchildren was examined related to length of residence in non-fluoridated Camrose (0.23 ppm) and adjacent fluoridated Wetaskiwin (1.08 ppm). The mean age was 11.94 +/- 0.65 years, 115 being examined in Camrose and 89 in Wetaskiwin. The mean DMFT and DMFS values were similar in both the non-fluoridated and fluoridated communities with DMFT of 2.39 and 2.65 and DMFS of 3.40 and 3.54, respectively. When a minimum 5-year residency requirement was imposed, the data changed, showing for those children with 5-year residency DMFT values of 2.43 and 2.26 and DMFS values of 3.35 and 2.79, respectively, for non-fluoridated Camrose and fluoridated Wetaskiwin. Although the fluoridated community had 17% less surfaces with caries, differences between the fluoridated and non-fluoridated communities were not statistically significant. Within the fluoridated community, differences in DMFT and DMFS between children resident less than 5 and greater than 5 years were statistically significant (DMFT p less than 0.05; DMFS p less than 0.01). When comparing regions where adjacent communities exist, with and without water fluoridation, and in making decisions on fluoride supplementation levels for children who have changed residency to such communities, it is important that this type of information is taken into account.     

A reassessment of the dental health of urban Scottish schoolchildren following the cessation of water fluoridation

A comparison was made between the dental health of children in two Scottish towns, one of which was fluoridated until 1983. The mean decayed, missing and filled (dmft) score was found to be 69 per cent lower in 5-year-old children in the fluoridated town compared with the non-fluoridated one and there was a similar 65 per cent difference for DMFT scores in those aged 15 years. 10-year-old children in the fluoridated town had a 39 per cent lower DMFT score, less than the 50 per cent difference found in the 1980 study. Comparison with an identical 1980 study allowed secular trends in caries prevalence to be examined. This revealed a 13 per cent reduction in dmft scores for 5-year-old children and a 16 per cent reduction in DMFT in 10-year-old children in the non-fluoride town. There was a 52 per cent reduction in dmft in 5-year-old children in the previously fluoridated town; however those aged 10 years had a higher DMFT score in 1986 than in 1980. Although this study found that there is a residual benefit from fluoridation in all age groups, there are indications of an adverse trend in dental health in the 10-year-old children in the fluoridated town. The investigation confirmed that the trend is towards lower caries levels amongst Scottish schoolchildren.     

Water fluoridation and dental caries in 5- and 12-year-old children from Canterbury and Wellington

OBJECTIVES: Claims have been made that the effectiveness of water fluoridation has reduced due to the widespread availability of other sources of fluoride. This study examines the differences in the oral health of children living in fluoridated and non-fluoridated areas of Canterbury and Wellington, New Zealand. DESIGN: The data used in this cross-sectional study had been routinely collected into a computerized data-collection system by the School Dental Services in the two study areas. SUBJECTS AND METHODS: Records of dental status (dmfs/DMFS), fluoridation status, ethnicity, and socio-economic status for 8030 5-year-olds, and 6916 12-year-olds in 1996 were analysed. RESULTS: Caries prevalence and severity was consistently lower for children in the fluoridated area for both age groups, and within all subgroups. Five-year-olds in the fluoridated area had 2.63 dmfs (sd, 5.88), and those in the non-fluoridated area 3.80 dmfs (sd, 6.79). For 12-year-olds the respective figures were 1.39 DMFS (sd, 2.30) and 2.37 DMFS (sd, 3.46). Multivariable analysis confirmed the independent association between water fluoridation and better dental health. CONCLUSIONS: This results of this study show children living in a fluoridated area to have significantly better oral health compared to those not in a fluoridated area. These differences are greater for Maori and Pacific children and children of low socio-economic status.     

Caries experience among schoolchildren in relation to community fluoridation status and town size

The objective of the present study was to determine the caries experience of schoolchildren aged 7-12 years from the Southeast area of S?o 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 S?o Paulo State provided by the State Health Department. After stratification by fluoridation status and town size, 29 towns were randomly selected to represent the Southeast area of S?o Paulo State, Brazil, and a total of 13,480 schoolchildren were randomly selected for this study. Calibrated dentists performed dinical examinations according to the WHO criteria. Caries experience and prevalence were significantly lower in fluoridated areas (1.9 DMFT, 2.1 dmft, 20% caries free) than in non-fluoridated 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 S?o Paulo State.     

Should the drinking water of Truro,Nova Scotia,be fluoridated? Water fluoridation in the 1990s

Abstract – An epidemiological assessment of differences in caries and fluorosis prevalences between children in Truro (< 0.1 ppm) and Kentville (fluoridated at 1.1 ppm in 1991), Nova Scotia, Canada, was completed in 1991. Out of a total of 429 children, in grades 5 and 6, in the two towns in 1991, 219 (51%) were examined. Parents answered a self-administered questionnaire investigating the sources of drinking water used by the children since birth, residence history, use of fluoride supplements, dentifrices, and other fluoride products during the first 6 yr of the life. The examination criteria differentiated between non-cavitated and cavitated carious lesions. Dental fluorosis was measured using the TSIF index. Examiner agreement was excellent. Of the children examined, 80 (36.5%) drank water (fluoridated or non-fluoridated) from municipal water systems during the first 6 yr of life. The children were assigned into five groups based upon residence history and exposure to fluoridated water during the first 6 yr of life. The percentage difference in mean DMFS scores between children in the fluoridated and non-fluoridated groups is 17% (delta DMFS1 =0.7) when non-cavitated carious lesions are included and 39% (delta DMFS2= 1.1) when they are excluded. The differences are not statistically significant. The significant risk factors associated with the DMFS1 and DMFS2 scores identified by a stepwise multiple regression analysis are: education level of the father, gender, and number of years of reported use of toothpaste during the first 6 yr of life. Dental fluorosis (mainly TSIF score of 1) was present in 41.5% and 69.2% of the children in the non-fluoridated and fluoridated groups, respectively. Residence in a fluoridated area and the educational status of the mothers were positively associated with fluorosis status. It was concluded that water fluoridation be recommended as a part of an overall plan to educate the public and the medical and dental professions with respect to the proper and safe use of fluoride products. Determination of an optimal concentration of fluoride to be added to the water should take into account all potential major sources of systemic fluoride intake during the first 6 yr of life, including foods and beverages.     

Dental health in schoolchildren 5 years after water fluoridation ceased in south-west Scotland

A follow-up study of the dental health of children resident in two towns in south-west Scotland, one of which had fluoridated water until 1983, was carried out at the end of 1988. Comparison with an identical 1980 study allowed trends in the prevalence of caries to be examined. In 1988, the mean, decayed, missing and filled deciduous teeth (dmft) score for 5-year-old children in Stranraer, the formerly fluoridated town, was 3.08, 24 per cent worse than the score of 2.48 reported in 1980. In Annan, mean dmft for 5-year-old children was 3.18 in 1988, 27 per cent lower than the 1980 dmft score of 4.38. The difference in caries prevalence between the two towns in 1988 was a non-significant 3.1 per cent compared with the 44 per cent difference found in 1980. Similar trends in caries prevalence were also found in 10-year-old children with mean DMFT scores of 2.28 in Stranraer and 2.56 in Annan in 1988, a 10.9 per cent difference compared with the 50 per cent difference reported in 1980. The Stranraer DMFT score was 37.4 per cent higher than the DMFT of 1.66 recorded in 1980, while in Annan, the mean DMFT of 2.56 was 23.6 per cent lower than the 1980 score of 3.35. The comparison confirms a trend to lower caries levels in Annan children in line with the general trend in caries prevalence in much of western Europe. However, despite the almost universal use of fluoride toothpaste, caries prevalence in Stranraer children has increased since fluoridation ceased to almost parity with children in the non-fluoridated area. This study shows that there is still a benefit to be gained in terms of lower caries rates by implementing water fluoridation despite the general decline in dental caries.     

The prevalence of caries in 5-year-old children living in fluoridated and non-fluoridated communities in New Zealand.

The prevalence of caries in 5-year-old children living in fluoridated and non-fluoridated communities was investigated. Clinical examinations were completed on 342 children, of whom 247 had been continuously resident in their towns. Children living in fluoridated communities had significantly lower mean dmft and dmfs than children living in non-fluoridated communities. There was a marked social gradient in the non-fluoridated communities, which was not observed in the children from the fluoridated communities.     

Dental caries and fluorosis among children in a rural Georgia area

PURPOSE: This IRB-approved study compared the caries experience, fluorosis prevalence, and plaque and salivary fluoride concentrations ([F]) in middle school (MS; N = 51) and elementary school (ES; N = 144) children residing in nonfluoridated and fluoridated communities in rural Georgia. All participants were exposed to fluoridated water at school (0.5-1.2 ppm), some received that level at home, and others received home water with < 0.1 ppm F. METHODS: Subjects' parents completed a questionnaire regarding fluoride exposure. Children were examined at school by two calibrated dentists. RESULTS: No significant differences were seen in DMFS+dfs between children with or without fluoridated home water, nor for those with or without fluorosis. MS children with non-fluoridated home water had lower mean salivary [F] values than MS children with fluoridated home water. No differences were found among MS and ES children in mean plaque [F] for those with or without fluorosis. CONCLUSIONS: Home water fluoridation had little effect on the variables measured. These findings appear to be due to fluoride exposure from fluoridated dentifrices, fluoridated drinking water at school, and the fluoride "halo" effect.     

Effect of fluoridation on dental health in 5-and 11-year-old Irish schoolchildren

Sixty percent of the population of the Republic of Ireland live in communities served with fluoridated water supplies. A study was carried out to compare dental caries levels, treatment needs, and the cost of meeting these needs, in one town with fluoridated water supplies and two smaller towns without. In the fluoridated town 5-yr-old children had 36% less caries and would cost 29% less to treat than the corresponding age group in the non-fluoridated towns. Restorative treatment levels in both areas were minimal for this age group. In the 11-yr-old children there was a 42% difference in DMFT and a cost saving in treatment required because of caries of 50% in favour of the fluoridated community. Anterior permanent teeth benefited most, with a reduction of 81% in mean DMFT. In both areas most of the decay was seen in the permanent first molar teeth. Restorative treatment levels, while higher for the 11-yr-old age group, were still unsatisfactory.     

Dental caries and enamel fluorosis among the fluoridated and non-fluoridated populations in the Republic of Ireland in 2002

BACKGROUND: A national survey of oral health of children and adolescents was carried out in the Republic of Ireland (RoI) in 2001/2002. AIMS: To compare the prevalence of caries between child and adolescent residents in fluoridated and non-fluoridated communities in the RoI whilst controlling for disadvantage. To compare caries levels amongst disadvantaged and non-disadvantaged groups with and without water fluoridation. To report the changes in caries levels between the 1960s and 2002 in RoI. To report the changes in dental fluorosis levels between 1984 and 2002. METHODOLOGY: Cross sectional oral health survey of a representative, random, stratified sample of 17,851 5-, 8-, 12- and 15-year-old children and adolescents in RoI. WHO examination criteria with the addition of visible, non-cavitated dentine caries were used for recording caries. Fluorosis was measured using Dean's Index. RESULTS: In the RoI the mean dmft/DMFT scores for 5-, 8-, 12-, and 15-year-olds were 1.2, 0.3, 1.1 and 2.3. For those with domestic water fluoridation since birth the scores were 1.0, 0.3, 1.1 and 2.1 respectively. In non-fluoridated areas of RoI the mean dmft/DMFT scores for 5-, 8-, 12-, and 15-year-olds was 1.7, 0.3, 1.3 and 3.2, respectively. For 5-, 12- and 15-year-old age groups dental caries levels were lower amongst children with fluoridated domestic water supplies (all p<0.0001). The prevalence of dental fluorosis has increased in RoI since 1984. 23% and 36% of 8- and 15-year olds respectively in fluoridated areas had Dean's Index scores at the questionable or greater level in 2002, compared with 6% and 5% respectively in 1984. CONCLUSIONS: Caries levels are lower among children with fluoridated domestic water supplies. Decay levels are much lower in 2002 than they were in 1984 and in the 1960s. The oral health of the less well off is worse than that of the rest of the population. The prevalence of dental fluorosis is higher amongst children and adolescents with fluoridated water supplies. Comparisons with 1984 data show an increase in the prevalence of fluorosis since that time.     

Dental Caries-reducing Effects of a Milk Fluoridation Project in Bulgaria

Objectives: The aim of the present study was to investigate the effects of a community-based milk fluoridation project on dental caries. Methods : Fluoridated milk was provided to about one-half of kindergarten and other schoolchildren in Asenovgrad, a town in the southern part of Bulgaria. The estimated daily milk consumption was 200 ml containing 1 mg of fluoride (～5 ppm F). Cross-sectional samples of 61/2-year-olds in Asenovgrad and Panaguriche (a nearby town selected as the reference community) were examined at the start of the study in 1988 and after three years. Additional cross-sectional samples of 7 1/2-year-olds in Asenovgrad who were and were not drinking fluoridated milk were examined at baseline and at three years to provided an internal control group. Samples of 6 1/2-and 8 1/2-year-olds from Asenovgrad and Karlovo were examined in 1993 to provide for five-year follow-up comparisons. Results : In 6 1/2-year-old children who had consumed fluoridated milk for three years, there was a decrease in the mean dmft per child of 40 percent and in the mean DMFT of 89 percent compared to children examined at baseline. Children in Asenovgrad who were 4 1/2 years old at the start of the study and had been drinking fluoridated milk for three years had on average 44 percent fewer dmft and 83 percent fewer DMFT at 7 1/2 years of age than those not drinking fluoridated milk. After five years the dmft index was 40 percent less and the DMFT index 79 percent less in those children who had participated in the full five years of the program compared to the control group. Conclusions : Results seem to confirm the caries-reducing effects of milk fluoridation found in previous studies. Unexpected large caries reductions obtained in this nonexperimental study, however, probably cannot be attributed to the fluoridation of milk alone. The mere introduction of the project might have led to other changes affecting dental caries, such as improved oral hygiene and better dietary habits.     

Caries prevalence in 6-, 11- and 14-year-old children in the Cyclades Islands, Greece

Following the World Health Organization criteria, a total of 1,604 out of 3,225 children aged 6, 11 and 14 years living on the 20 islands of the Cyclades complex were examined. Recordings showed that in the 6-year-old children, the mean dmft index was 2.21 (SD=3.00) with 46% caries free. In the 11-year-old children, the DMFT averaged 1.39 (SD=1.78) with 46% caries free. In the 14-year-old children, the mean DMFT was 2.62 (SD=2.83) with 32% caries free. Statistically significant differences were found in the DMFT of the 11- and 14-year-old subjects living in naturally water fluoridated and non-fluoridated areas. According to these data, it appears that the first two WHO targets for the year 2000 are almost fulfilled.     

Dental health of 12-year-olds in Israel-2002

OBJECTIVE: To gather epidemiological information on caries prevalence and treatment needs of Israeli 12-year-olds. RESEARCH DESIGN: Prevalence survey of a representative sample of 12-year- olds examined according to WHO Oral Health Survey methods. RESULTS: The mean DMFT was 1.66 (DT = 0.91, MT = 0.03 FT = 0.72), a 40% decline since the previous national survey in 1989. DT and DMFT were lower amongst males (p < 0.01). There were no differences between urban and rural communities. Arab subjects had a higher prevalence, higher DT, MT and DMFT (p < 0.01), but lower FT than the Jewish subjects. In fluoridated areas, the mean DMFT was 1.39 compared to 1.83 in the non-fluoridated areas (p < 0.01). SiC (Significant Caries Index which shows the average DMFT of the third of the population with the highest DMFT) was found to be 4.31. CONCLUSIONS: Caries prevalence has declined among 12-year-olds in Israel. However, 53.9% of the children still suffer from caries at this age. There are wide dental health disparities.     

Five-year double-blind fluoridated milk study in scotland

A 5-yr double-blind fluoridated milk study has been completed and, following baseline stratification, 94 children aged 4 1/2/5 1/2 yr were allocated to the test group and 93 to the control. Each subject received 200 ml school milk daily, identification between the test and control plastic packs being by colour-coding alone with the former containing 1.5 mgF- giving a potential topical benefit of approximately 7 ppmF- per school day. After 5 yr, 50 of the test children remained and 56 of the controls. While the mean DMFT incremental data relating to permanent teeth was always in favour of the test group, it was not until the fourth year that a significant difference was obtained (P less than 0.01) between the fluoridated group (mean, 1.65) and the non-fluoridated group (mean, 2.56). For permanent teeth which were unerupted at baseline, the mean DMFS differences increased to 39.6% at the same time and to 48.0% by the fifth year. No benefit was noted for previously erupted primary teeth. Cavitation was less in the test group throughout the study. When the third, fourth and fifth year DMFT reductions obtained were compared with previously published artificial water fluoridated data where children were of comparable age at the onset of water adjustment, similar caries inhibition data were noted.     

Caries frequency in permanent teeth before and after discontinuation of water fluoridation in Kuopio, Finland

Abstract– The piped water of Kuopio, Finland, was fluoridated in 1959. Owing to strong opposition by different civic groups, water fluoridation was stopped at the end of 1992. Objectives: The aim of this study was to examine the consequences of the discontinuation on dental health. Methods: In 1992 and 1995, independent random samples of all children aged 6, 9, 12 and 15 years were drawn from Kuopio and Jyväskylä, a nearby low fluoride town whose distribution of demographic and socio-economic characteristics was fairly similar to Kuopio's. The total number of subjects examined was 550 in 1992 and 1198 in 1995. Caries was registered clinically and radiographically by the same two calibrated dentists in both towns. Results: In 1992, the mean DMFS values were lower in the fluoridated town for the two older age groups, the percentage differences for 12- and 15-year-olds being 37% and 29%, respectively. For the two younger age groups no meaningful differences could be found. In 1995, the only difference with possible clinical significance was found in the 15-year-olds in favor of the fluoridated town (18%). In 1995, a decline in caries was seen in the two older age groups in the nonfluoridated town. In spite of discontinued water fluoridation, no indication of an increasing trend of caries could be found in Kuopio. The mean numbers of fluoride varnish and sealant applications decreased sharply in both towns between 1992 and 1995. In spite of that caries declined. Conclusions: These findings suggest that the decline of caries has little to do with professional preventive measures performed in dental clinics.     

Prevalence of caries and developmental defects of enamel in 9-10 year old children living in areas in Brazil with differing water fluoride histories

AIMS: To assess the prevalences of caries, of developmental defects of enamel and their interrelationship in Brazilian 9-10-year-olds from areas of contrasting fluoridation histories. METHODS: Systematic random sampling procedures were used to select children from an area where water had been fluoridated in 1963 and from a second area where water had been fluoridated since 1998. Clinical examinations for caries were carried out using the DMFT index and WHO diagnostic criteria. Developmental defects of enamel on upper incisors were diagnosed using the DDE index. RESULTS: A difference of 40% in DMFT was observed, with a lower prevalence of disease in the area fluoridated since 1963. Diffuse opacities affected 14.3% of the children from the area fluoridated since 1963 compared with only 2.4% in the area fluoridated in 1998. Children living in the area fluoridated in 1963 who had diffuse defects had twice the chance of being free from caries compared with those living in the same area who had no defects or who had only demarcated or hypoplastic defects. CONCLUSIONS: This study confirms previous ones in showing the benefits of water fluoridation. Diffuse opacities of upper incisors affected relatively few subjects in either of the two areas.     

Fluoridation in Anglesey: a clinical study of dental caries in mothers at term.

A study of dental caries was carried out involving 1537 mothers who attended St David's Hospital, Gwynedd, between July 1986 and July 1987 for their confinement. The study was 'blind' in respect of residence. The mean DMFT value for mothers with continuous residence in the non-fluoridated Gwynedd mainland was 13.6 and the mean DMFT value for mothers living in the Anglesey Health Unit who had consumed fluoridated mains water from birth was 30% lower at 9.5 (P less than 0.0001). The confidence interval for the difference between means was 3.4-4.9. The samples from the two areas showed no significant differences in social class and age group structures. The percentage of Anglesey mothers with DMFT exceeding 15 was less than one-sixth of that for mainland mothers and the percentage of those with DMFT less than 6 was three times greater. The mean DMFS value for occlusal sites in premolars was 3.9 for mainland Gwynedd and for Anglesey 52% less at 1.9 (P less than 0.0001) with a confidence interval of 1.6-2.4. For smooth surface sites in posterior teeth, the difference was not as pronounced, with a mean DMFS value for mainland of 20.3 and for Anglesey 42% less at 11.8 (P less than 0.0001) with a confidence interval of 7.5-9.6. The results showed that child-bearing women continued to enjoy important benefits from water fluoridation into their early thirties.     

A comparison of dental caries levels in two communities with different oral health prevention strategies stratified in different social classes

OBJECTIVES: To compare dental caries levels of schoolchildren stratified in different social classes whose domestic water supply had been fluoridated since birth (Dublin) with those living in an area where fluoridated salt was available (Freiburg). METHODS: A representative, random 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 used. The caries levels showed a reduced disparity between children in social class 2 (medium) and 3 (lowest) in Dublin compared with those in social class 2 and 3 in Freiburg. CONCLUSIONS: The evidence from this study confirmed that water fluoridation has reduced the gap in dental caries experience between medium and lower social classes in Dublin compared with the greater difference in caries experience between the equivalent social classes in Freiburg. The results from this study established the important role of salt fluoridation where water fluoridation is not feasible.     

Dental caries prevalence amongst 12-year-old urban children in East Africa

It is commonly believed that the prevalence of dental caries in developing countries is increasing, though in Kenya and Tanzania there is insufficient information to confirm such trends. In order to test the hypothesis, therefore, 762 children in Dar es Salaam and 802 children in Nairobi aged 12 yr in 1984 were examined for dental caries as part of a baseline study to monitor changes of prevalence with time. Dental caries was recorded by surfaces using the criteria recommended by the WHO and examinations were performed by standardized examiners. The mean DMFT in Dar es Salaam of 0.67 (SD 1.20) was significantly higher than that for Nairobi, 0.51 (SD 1.23). No differences were found in the mean DMFS index. Nairobi children had a greater number of filled teeth and surfaces. Although a greater proportion of children were caries-free in Nairobi than in Dar es Salaam, amongst those with caries, Nairobi children had significantly higher DMFS scores, and a greater proportion with DMFS greater than 4. The possible reasons for such findings are discussed. The mean DMFT and DMFS reported here are amongst the lowest reported in the recent literature from both countries.     

Caries prevalence after cessation of water fluoridation in La Salud, Cuba

In the past, caries has usually increased after cessation of water fluoridation. More recently an opposite trend could be observed: DMFT remaining stable or even decreasing further. The aim of the present study conducted in La Salud (Province of Habana) in March 1997 was to analyse the current caries trend under the special climatic and nutritional conditions of the subtropical sugar island Cuba, following the cessation, in 1990, of water fluoridation (0.8 ppm F). Diagnostic evaluations were carried out using the same methods as in 1973 and 1982. Boys and girls aged 6-13 years (N = 414), lifelong residents in La Salud, were examined. Between 1973 and 1982 the mean DMFT had decreased by 71.4%, the mean DMFS by 73. 3% and the percentage of caries-free children had increased from 26. 3 to 61.6%. In 1997, following the cessation of drinking water fluoridation, in contrast to an expected rise in caries prevalence, DMFT and DMFS values remained at a low level for the 6- to 9-year-olds and appeared to decrease for the 10/11-year-olds (from 1. 1 to 0.8) and DMFS (from 1.5 to 1.2). In the 12/13-year-olds, there was a significant decrease (DMFT from 2.1 to 1.1; DMFS from 3.1 to 1. 5), while the percentage of caries-free children of this age group had increased from 4.8 (1973) and 33.3 (1982) up to 55.2%. A possible explanation for this unexpected finding and for the good oral health status of the children in La Salud is the effect of the school mouthrinsing programme, which has involved fortnightly mouthrinses with 0.2% NaF solutions (i.e. 15 times/year) since 1990.