Comparison of trends in the prevalence of caries and restorations in young adult populations of several countries

We compared DMFT (decayed, missing and filled teeth) values of young adult populations (about 18- to 21 yr old) obtained over two decades in five industrialized countries (Denmark, Finland, Israel, Japan, U.S.A.). Trends of the active disease factor (D) and treatment factor (F) within and between these countries during two decades were also compared. No uniform trend in caries prevalence data, based on total DMFT scores, was found. In some countries DMFT scores declined (Denmark, U.S.A.), in some they remained relatively static (Finland), and in some they increased during the last 20 yr (Israel, Japan). However, DMFT scores did not always correlate with untreated lesions, D, which decreased remarkably in Denmark and Finland and moderately in the U.S.A., remained stable in Japan, but increased in Israel. Similarly, treatment of caries, F, varied in different countries, increasing dramatically in Finland and Japan and moderately in Israel, remaining static in Denmark, and decreasing in the U.S.A. These trends appear to be influenced largely by the extent of caries-preventive measures (particularly fluorides) in the respective countries, and to a lesser degree by sugar utilization and the availability of dental personnel. This age population has not been studied in a comparative fashion previously. This study also emphasizes the importance of looking not only at DMFT scores but at the trends in meeting treatment needs, D vs F scores.     

The caries decline: a review of reviews

The aim of this paper is to review publications discussing the declining prevalence of dental caries in the industrialized countries during the past decades, focusing on some main conferences addressing this issue. Has there been a real decline in the prevalence of dental caries? Several excellent papers and reviews have been published, and there is a general agreement that a marked reduction in caries prevalence has occurred among children in most of the developed countries in recent decades. This fact has stimulated much debate and attempts to identify the most likely explanations for this change. The conclusion made from this review is that the various authors believe that the use of fluoride in various forms has contributed most significantly to the decline in dental caries prevalence. A number of other factors must, however, also be taken into consideration, and such factors have been extensively discussed in the various publications.     

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.     

Reasons for the caries decline: what do the experts believe?

The aim of this paper was to describe what experts of today believe are the main reasons explaining the caries decline seen in many westernized countries over the past 3 decades. We have collected the views of a number of international experts, trying to answer the specific question “What are the main reasons why 20-25-year-old persons have less caries nowadays, compared to 30 years ago?”. A questionnaire was mailed to 55 experts with a number of thinkable explanations to be scored according to a predetermined scale. The 25 items were divided into main groups under the heading of diet, fluorides. plaque, saliva, dentist/dental materials and other factors. The experts were asked to think of a specific country or area, and also to specify whether the chosen area had water fluoridation or not. The main finding of our study, based on a 95% response rate, was that there is a very large variation in how the experts graded the impact of various possible factors. For the use of fluoride toothpaste, there was a clear agreement of a definite positive effect.     

Effects of lifelong consumption of fluoridated water or use of fluoride supplements on dental caries prevalence

Abstract This study was undertaken to determine the prevalence of dental caries in children ages 6–14, from fluoridated and non-fluoridated areas in British Columbia, Canada, and the effects of receiving certain fluoride preventive procedures during childhood. Children from two communities were surveyed using a modified Decayed, Missing and Filled Tooth Surface Index (D₁ D₂ MFS). Questionnaires on the use of various fluoride preventive practices and residence histories during childhood were collected. Completed questionnaires were returned and exams were performed on 1131 children. Crude caries prevalence scores for the different fluoride exposure groups were tested for differences in dental age and the level of educational attainment of parents and/or guardians. No significant group differences were found. The 110 children with lifelong exposure only to fluoridated water had 35%, or 0.88 (S.D. = 2.91), fewer decayed or filled tooth surfaces per child (P(0.07) than children with no reported exposure to systemic fluorides. For the 122 children who had taken fluoride supplements for 4 yr or more, 0.67 fewer decayed and filled tooth surfaces (26% reduction) were observed per child when compared to children with no exposure to fluoridated water or supplements. For children who used fluoride supplements for less than 4 yr, no significant benefits were observed. Approximately 75% of the caries prevalence for control and fluoride-exposed groups was on pit and fissured surfaces. Reductions by surface type showed savings on both smooth and pit and fissured surfaces.     

Factors for changes of caries prevalence among adolescents in Germany

Data on caries prevalence among adolescents in East and West Germany before and after unification (1990) were compared with changes in etiologic and preventive parameters. The postwar increase of total sugar consumption resulted in an increase of caries prevalence among adolescents in both East and West Germany until 1970. Parallel to the introduction of preventive measures, especially systemic fluoridation, the national caries level in East Germany stabilized at 4–5 DMFT (in 13–14–year–olds) with significant regional differences. The introduction of fluoridated toothpaste after 1973 in West Germany was followed by a caries decline in children (1970s) and in adolescents (1980s) from very high caries levels (8.8 DMFT in 13–14–year–olds in 1983) to moderate levels (5.1 DMFT in 1989). The sudden increase from 10% to 90% fluoridated toothpaste in East Germany in 1990 was also accompanied by a caries decline in adolescents. Group prevention, which included fluoride varnish programs and the introduction of free prevention (brushing instructions, fluoridations. sealants) at private dentists for 6–19–year–olds since 1983. seems to be responsible for the latest caries reductions all over Germany.     

Decline in caries prevalence in6–14-year-old schoolchildren during1975–85 in Shizuoka, Japan

The purpose of this study was to examine changes in caries prevalence during 1975-85 in Japanese schoolchildren who did not have an apparent change in fluoride exposure. A total of 2872 schoolchildren aged 6-14 yr in two primary schools and one junior high school in Shizuoka city, Japan, were examined in 1985. The caries prevalence in 1985 was then compared with data which had been collected in a longitudinal survey on schoolchildren in the same primary and junior high schools by Katayama in 1970-75. The results indicated that DMFT and DMFS indices in 1985 were significantly lower than those in 1970-75 in all the examined ages (P < 0.01). The DMFT indices at age 12 were 3.60 in 1985 and 5.47 in 1970-75. Remarkable decreases in DMFT at age 12 were observed in maxillary incisors (50%), followed by maxillary molars (24%) and mandibular molars (22%). The decline in caries prevalence in the examined area may be mainly attributed to several factors other than use of fluoride, such as changes in dietary pattern, an increasing dental awareness and promotion of dental health care. But the percentage decrease per annum of DMFT index at age of 12 in the examined population was relatively low (-4.1%) in comparison with other industrial countries. Comparing the results with data from national dental surveys, it can be considered that rural areas in Japan do not exhibit a similar decline of caries prevalence as in Shizuoka city, but there will be a lot of districts exhibiting significant reduction in caries prevalence in the near future.     

Changes in the caries prevalence of 11–12-year-old schoolchildren in the North-West of England from 1968 to 1981

Abstract Since 1968, six caries clinical trials have been conducted in the North-West of England by different examiners using the same diagnostic system, and a steady reduction in caries prevalence in 11–12-yr-old schoolchildren has been recorded. In the present study, five of the examiners revisited some of the schools which participated in their original trials and each examined between 196 and 296 children. The time intervals between the original and repeat examinations were 12, 10, 8, 5 and 3 yr. Percent caries reductions (PCRs) ranged from 19 to 33 for DMFT and from 24 to 35 for DMFS but the PCRs did not relate to the time intervals between examinations. The PCRs were greater on free smooth and approximal surfaces than on fissure surfaces and for the anterior teeth than for the mouth as a whole, suggesting that fluoride may have played a role in the reductions.     

Dental caries prevalence in schoolchildren of Baghdad province, Iraq

Abstract The First National Oral Health Survey on caries prevalence was estimated on 1213 Iraqi primary schoolchildren aged 6–12 years from mixed socioeconomic levels, to provide a baseline data for future planning of dental services. The mean dill was 5.2±3.6 for the 6-year-olds and 11 % of the children were caries free. For the permanent teeth caries experiences were 0.6±1.0, 1.4±1.5 and 2.7±2.4 for ages 6, 9 and 12 years respectively and the rate of caries free children were 67%, 40% and 21% for the respective ages. The majority of the dift and DIMFT indices were due to decayed teeth and almost no restorations were found.     

Changes in the prevalence of caries in children and adolescents in Sweden 1985–1994

The prevalence of caries among 3-. 6-. 12- and 19-year-olds in Sweden was followed during the period 1985–1994 through county council reports to the National Board of Health and Welfare. Nearly all the county councils take part in this reporting, and the details for 1994 were based upon 74% of all the country's 12-year-olds and 81% of all the 19-year-olds. Particulars of caries are noted during the annual examination at national dental service clinics. Only manifest caries is recorded. For the age groups studied, the prevalence of caries diminished markedly during the period. The proportion of caries-free 3- and 6-year-olds increased. In 1994. 91% of the 3-year-olds and 64% of the 6-year-olds were free of caries in the deciduous dentition. DFT for 12-year-olds sank from 3.1 to 1.5 during 1985–1994. For 19-year-olds, DFT changed from 8.5 to 5.2. while the proportion of individuals who were caries-free on approxi-mal surfaces increased from 36% to 58%. The change for DFS-a (carious or filled approximal surface) was from 3.4 in 1985 to 1.6 in 1994. These changes in the mean values were accompanied by changes in the frequency distribution of the values for DFT and DFS-a. The proportion of severely carious individuals decreased greatly during the 10-year period studied. At the same time, the differences in caries prevalence among the 26 county councils evened out.     

Dental caries prevalence in intermediate Saudi schoolchildren in Riyad

Abstract The study was performed in 1378 intermediate Saudi schoolchildren in Riyad, 693 females and 685 males. The results indicate low caries prevalence among Saudi children. This may be due to the type of food eaten, and other factors could be important, e.g. the use of miswak by Saudi children as the traditional practice for brushing teeth. The difference between the DMFT of the total number of Saudi females and males by sex and age were not statistically significant, P > 0.7498 and P > 0.1808, respectively. The chi-square analysis for treatment needs between females and males indicate that the differences were not statistically significant (X²= 0.254, I df, P= 0.6145). The most prominent finding was a high percent (77.65%) of treatment needs for Saudi children. This confirmed the continuous need for planning and delivering dental services.     

The prevalence of dental caries and fluorosis in Japanese communities with up to 1.4 ppm of naturally occurring fluoride

OBJECTIVES: The purpose of this study was to determine the relationship between the concentration of fluoride in drinking water and the prevalence of dental caries and fluorosis in seven Japanese communities with different concentrations of fluoride occurring naturally in the drinking water. METHODS: A total of 1,060 10- to 12-year-old lifetime residents were examined to determine the prevalence of dental caries and fluorosis in communities with trace amounts to 1.4 ppm fluoride in the drinking water in 1987. Systemic fluorides (drops or tablets) have never been available in Japan and the market share of fluoride-containing toothpaste was 12 percent at the time of the study. RESULTS: The prevalence of dental caries was inversely related and the prevalence of fluorosis was directly related to the concentration of fluoride in the drinking water. The mean DMFS in the communities with 0.8 to 1.4 ppm fluoride was 53.9 percent to 62.4 percent lower than that in communities with negligible amounts of fluoride. Multivariate analysis showed that water fluoride level was the strongest factor influencing DMFS scores. The prevalence of fluorosis ranged from 1.7 percent to 15.4 percent, and the increase in fluorosis with increasing fluoride exposure was limited entirely to the milder forms. CONCLUSIONS: The findings of this study conducted in 1987 in Japan parallel those reported by Dean et al. in the early 1940s.     

Changes in prevalence of approximal caries in 17-year-olds and related restorative treatment strategies over a 6-year period

Two cohorts of 17-yr-olds treated in a municipal child dental service in 1978-79 and 1984-85 had bitewing radiographs taken at the examination before the last course of treatment in the service. All radiographs were read by one examiner, who did not know to which cohort the individual belonged. The subsequent treatment was recorded from the treatment records by another examiner, who was unaware of the results of the radiographic examination. According to radiographic scores, the proportion of decayed or filled (DFS) approximal surfaces had decreased from 23.2% to 17.4% during the period (difference: 25%). The proportion of unfilled surfaces which were decayed (DS) had remained almost constant, while 9.6% of the surfaces were filled (FS) in 1978-79 compared to 3.1% in 1984-85 (difference: 68%). Thus, in spite of a 25% decrease in total caries experience (DFS), a reduction of 68% would be claimed if fillings (FS) were interpreted as expression of disease prevalence. The risk of an approximal surface being filled decreased to about one fifth from 1978-79 to 1984-85, and the risk of being filled was nearly three times as high for approximal surfaces of children who already had approximal fillings at the time of examination. Thus, both the year of examination and the subject's previously received treatment seemed to influence the treatment strategy of the dentist.     

Relationship of oral hygiene and sugar consumption to risk of caries in children

Abstract The associations of denial caries with poor oral hygiene and high sugar consumption were analyzed taking into account possible confounding and factor interaction. The series consisted of 543 children from low-fluoride areas (0.10–0.46 parts/10⁶), aged 5, 9 and 13 years Plaque accumulation and sugar consumption were slightly confounded throughout the observations. Effect-modification appeared to exist, since the effect of one factor was greater at higher levels of the other. The association between the amount of plaque and dental caries was statistically significant at all levels of sugar consumption. With increasing total sugar consumption the risk of caries increased significantly only when oral hygiene was simultaneously poor. Effect estimates (E) and attributable risk estimates (AR) were calculated for increased plaque accumulation and sugar consumption. For the total sets of tooth surfaces in the various age groups the proportions of the total caries load associated with increased plaque accumulation were 35.2–63.0%, and those associated with higher total sugar consumption 0.7–5.4%. The fractions varied greatly with the tooth group. The effect estimates for the two factors in combination were always greater than the sums of the separate effects, indicating synergistic interaction between the two caries determinants.     

Using the DMF gender difference to assess the "major" role of fluoride toothpastes in the caries decline in industrialized countries: a meta-analysis

Abstract The regular use of fluoridated toothpastes has been ascribed a major role in the observed decline in caries prevalence in industrialized countries during the last 20 to 25 years, but only indirect evidence supports this claim. The purpose of this study was to test the hypothesis that the more frequent use of fluoride toothpastes by girls than by boys has reduced the relative age-specific D(M)FT gender difference, and that this difference should decrease with increasing age and fluoride toothpaste exposure among adolescents. The material comprised 8,777 subjects 12 to 17 years of age from the pre-fluoride toothpaste era (1946–1959) and 39,903 from the period when use of fluoride toothpaste had become common (1983–1993) in industrialized countries. Meta-analyses were done using the relative age-specific mean D(M)FT difference between girls and boys. Separate analyses were carried out for subgroups of studies/countries to check for confounding. Regardless of analytical approach, no evidence was found to support the hypothesis. It is concluded that the gender difference in fluoride exposure due to tooth brushing frequency is too small to matter, that the study lacked power, or that the role of fluoride toothpastes in the caries decline has been overrated.     

Changing time trend in caries prevalence in Norwegian children and adolescents

Abstract The purpose of the present study was to determine whether or not the decline in caries prevalence had continued among Norwegian 5-, 12- and 18-yr-olds from 1985 to 1991. The analysis was carried out at national, county and dental district level based on the annual census reports from public dental officers. Caries decline continued at national level. Some counties exhibited increases from 1 year to the next, more so in the last 3 years than in the first 3 years of observation, but not consistently. There was stronger evidence for a leveling out or reversal of caries trend at district than at county level. Reversal affected more 5- than 15-yr-olds and more 12- than 18-yr-olds. The chief dental officers in districts reporting a reversal of trend in caries prevalence and in comparison districts showing continued caries decline were interviewed by telephone concerning factors which might explain the observed caries trend. The interviews revealed no obvious explanation why caries prevalence increased in some dental districts while it continued to decline in others. It is concluded that a reversal in caries trend has occurred in some Norwegian dental districts between 1985 and 1991 and that there is a need for a more detailed study of the situation.     

Dental caries experience and prevalence of children afraid of dental treatment

The aim of this study was to examine the clinical outcome with regard to dental caries of high self reported dental anxiety in a group of Scottish secondary schoolchildren. 1103 children participated in the study, mean age 14 yr (sd 0.35 yr), and the prevalence of high dental anxiety was 7.1% (95% CI = 5.6%, 8.6%). When these children were compared with their contemporaries their DMFT and all its components were higher but only the mean MT reached statistical significance after adjusting for gender and social class. Children with a high dental anxiety were 62% more likely to have at least 1 missing tooth due to caries. In addition this group when compared to the rest of the study population, had a significantly lower mean number of teeth fissure sealed and a lower proportion of children with sealants. No similar trend was obvious for children who had a high general fear. The dentally anxious more accurately perceived their treatment need and were more likely to defer, cancel or not turn up for dental appointments.     

A marked difference in caries prevalence between 5-year-old children in two areas of Staffordshire, England

The purpose of this study was to compare the dental caries experience of 5-year-old children in an urban and rural area of Staffordshire, England. The populations comprised 365 children and 206 children, respectively. 161 children in the urban area and 124 children from the rural area were examined. Those in the rural area had 44% less dental caries experience (P less than 0.01). The mean dmf of children with good dental cleanliness was similar in each area but there was a 39% and 33% interarea difference between those with fair and poor standards of dental cleanliness. A larger proportion in the rural area belonged to social classes 1 + 2 and fewer to social classes 4 + 5. A significant difference in dmf (P less than 0.01) between the areas in social classes 3N and 3M was found. Water supplies had less than 0.20 parts/10(6) fluoride. The interarea difference in caries prevalence cannot be fully explained by consideration of the variables of dental cleanliness, social class and waterborne fluoride. It is hypothesized that tooth resistance may differ between the areas. The study will be repeated to confirm the findings.     

Dental caries: intervened – interrupted – interpreted

This paper comprizes a summarizing discussion for a set of 13 papers on the theme caries decline. The complexity of the issue is highlighted, and it is concluded that there is not one single factor explaining the changes observed. Actually, in one and the same population, different explanations may be relevant for different individuals, for different age groups, for different teeth and for different periods of time. A new model for understanding the interaction of various caries etiological factors is proposed. The model can illustrate how in one situation caries activity can increase (or decrease) due to one such factor, while in another situation different factors are more important. As it, in a graphic way, maps the interactions of relevant factors, the author has chosen to call it a cariogram, and the process of preparing such graphs, cartography.     

High prevalence of mutans streptococci in a population with extremely low prevalence of dental caries

The quantitative distribution of the mutans streptococci was investigated in populations with very low caries prevalence. Three hundred and seven school children from rural Sudan with an estimated age of 12 years were examined for dental status and salivary mutans streptococci. Forty-two isolates from the salivary cultures were determined to species level by studying the serogroup and biotype. Denial caries in permanent teeth was diagnosed in 12% of the children and the mean DMFT was 0.17 (range 0-6 DMFT). Caries was confined to fissures. Mutans streptococci were found in 96% of the children and high counts were obtained in 45%. Of 42 isolated strains, 37 belonged to Streptococcus mutans , 5 to Streptococcus sobrinus and none to Streptococcus rattus. The observations show that the mutans streptococci can be widespread in human populations with extremely low prevalence of dental caries and consequently that these bacteria may be readily propagated in human populations without association to a caries-promoting life style.