J. Dent. 1990;
18: 291-295
291
Caries in the preschool international trends
child:
A-K. Holm Department
of Pedodontics,
University
of Ume& Sweden
ABSTRACT Most studies on the prevalence and incidence of dental caries are carried out on schoolchildren and data on preschool children are comparably few. In most of the developing countries in South East Asia, children have a high prevalence of dental caries in the primary dentition, often in contrast to the situation in the permanent dentition. The reasons for this difference are not obvious, but may be linked to differences in diet. In Africa, dental caries prevalence in the preschool child seems to be increasing somewhat in countries or parts of countries where there is an increase in sugar intake, while it stays low in countries where a poor economy restricts sugar intake. The prevalence does not seem to be as high as in South East Asia. In most industrialized countries in northern Europe, in North America, in Australia and New Zealand, dental caries is decreasing, often linked to an increasing use of fluorides, to various types of dental health education programmes, etc. In many European countries, the prevalence in preschool children is, however, still high and caries in primary teeth is often left untreated. In Scandinavia, where all preschool children are included in an organized dental care programme, dental caries has been decreasing markedly during the 1970s and at the beginning of the 1980s. While the mean values for d.m.f.t. at present appear to be largely unchanged, there seems to be a change in the distribution of the disease. More and more children are totally free of the disease, while the group with high d.m.f. values has a tendency to increase. KEY WORDS:
Dental caries, Preschool child, Trends
J. Dent. 1990; 18: 29 l-295 (Presented at ‘Caries and the Preschool Child’, a symposium Society, 22 May 1990, London, UK.) Correspondence should be addressed S-901 87 Ume& Sweden.
ro: Professor A-K. Holm, Department
Over the past decade, the decreasing caries incidence in children has been documented in several studies. Most of them have dealt with children in the industrialized countries, where the decline in dental caries, with a few exceptions, is indisputable. Most authors seem to agree that the widespread use of fluorides is the main reason for the decline in dental caries, but that other factors like improved oral hygiene and changes in eating patterns have had an impact. The dental health of the preschool child has not nearly been documented to the same extent as the dental health of schoolchildren. This is probably because primary teeth in many countries still are not considered to be as important or as valuable as permanent teeth, and also because in many of the developing countries, the older children may be going to school and are easier to identify and include in oral health surveys. One of the goals set by WHO for Oral Health by the 0 1990 Butterworth-Heinemann 0300-57 12/90/06029 I-05
Ltd.
of the British Paedodontic
of Pedodontics,
University
of Ume&
Year 2000, is for 50 per cent of the 5-6 year olds to be totally free from dental caries. This seems to be a rather modest goal, but there are many countries where it still appears very remote. What is the caries situation of the preschool child today in countries that lie outside Great Britain, and can we discern any trends in the disease pattern? As was mentioned earlier, data on preschool children are rather limited, but some studies have been published in recent years. In the majority of the studies to which I will be referring, WHO methods and criteria have been used in the diagnosis of dental caries (WHO, 1987).
SOUTH
EAST ASIA
Data on dental health of preschool children in South East Asia are sparse. One study has, however, recently been
292
J. Dent. 1990; 18: No. 6
Table1. Caries prevalence in preschool children in some countries in South East Asia Children
Year
Age
(no.)
hfr)
Beijing, China Kandy, Sri Lanka Malaysia
1987 1984 1986
120 280 509
6 ;I:
Thailand
1986
599
5-6
Country
published on the dental health of 6 and 12 year olds in the city of Beijing (Table I). The study was carried out by a team of Australian and Chinese dentists (Wright et al., 1989) and includes 100 children in each age group. There is a striking difference in caries prevalence between the groups. While only 5 per cent of the 6 year olds are caries free, the corresponding figure for the 12 year olds is 54 per cent. The 6 year olds had a mean d.m.f.t. of 6.3 and a mean d.m.f.s. of 12.0.The d-component was close to 80 per cent. These children resided in a central area of Beijing, and their dental awareness may be higher than average. Thus, 74 per cent said that they used a toothbrush to clean their teeth. In Sri Lanka, preschool and school children are given dental care by dental nurses after the New Zealand model, however, there is only one nurse per 30000 children. A survey of the dental health of 3-5 year olds, carried out in 1984 (Amaratunge et al., 1986), showed a very serious caries situation with 90 per cent of 3 year olds affected by dental caries and d.m.f.s. values of the 5 year olds close to 11 (Table I). Between 50 and 60 per cent of 3-5 year olds had carious incisors. According to the authors, a team of Danish and Sri Lankan dentists, the nurses are overwhelmed by the size of the treatment needs. The authors are not inclined to say anything definite about the trends in dental health in preschool children, but point towards the fact that the 3 year olds had a higher caries prevalence than the 5 year olds. They explain the rapid, rather uncontrolled caries in the primary dentition to be due at least partly to the increased consumption of refined sugar-containing snacks in the urban areas of Sri Lanka during the last decade. In Malaysia, children between 3 and 6 years of age, selected from private schools, were caries free in 21 per cent and had a mean d.m.f.t. of 5.4 (Table Z) (Majid et al., 1987). Rampant caries was found in 16 per cent of the children. There are no previous data in preschool children to compare with, but the authors, a team from the dental faculty of Kuala Lumpur, consider caries to be increasing, and blame the situation on easy access to confectionary and soft drinks. Thailand has a highly developed system of primary health care. In an extensive survey from 1986 (Songpaisan and Davies, 1989),including both children and acults, the preschool children amounted to 600. These children showed large variations in their caries experience, for reasons that are not really given (Table I). The most
% Caries
free 5 :y 9-39
x d.rn.f.t. x d.m.f.s. ::: ;::-8.2
12.0 11.0 -
conspicuous feature was a low caries prevalence in the permanent dentition compared to a much higher prevalence in the primary dentition. There is some speculation in the paper about the possibility of the children included being undernourished, this in turn predisposing to linear enamel hypoplasias which in turn would increase the risk of dental caries, however the diet of the children is not mentioned. If China, Sri Lanka, Malaysia and Thailand are taken to represent four countries in the south-east of Asia, where resources for dental care to preschool children are, or have been, very limited, then the situation in Japan ought to be of interest. In this highly industralized country there are 29 dental schools and a high dentist to population ratio. Dental caries is, however, still very prevalent in Japan. According to a short note published by Katayama and Rugg-Gunn in 1986, there has been no decline in dental caries prevalence in Japan comparable to that recorded in other industrialized countries. In 1981, the d.m.f.t. at the age of 5 was 8.2, a lower value, however, than in 1975. According to the Ministry of Health & Welfare in Japan, 66.7 per cent of 3 year olds had dental caries in 1987 compared to 72.4 per cent in 1981, indicating an improvement (Noda T., 1990,personal communication). The main reasons for the high caries prevalence in Japan are probably a fairly high sugar consumption in combination with a restricted use of fluorides. The discernible trend in the dental caries prevalence of preschool children in South East Asia seems to be that dental caries is increasing.
AFRICA The caries situation in many African countries is different from that found in South East Asia. In Tanzania, one of the countries where several epidemiological surveys have been performed, lately data on preschool children have also been published. Mosha and Robison (1989) showed in a study performed in 1985 that 5-7 year olds, all residing in Dar es Salaam, had a d.m.f.t. of 1.1 (Table II). Sixty-two per cent were caries free. The figures should be regarded as maximum figures, as the children were all selected from nursery schools, where children are likely to have a higher socioeconomic background than children who do not attend. In developing countries, children from higher socioeconomic groups, often residing in the urban more
Holm: Caries in the preschool
child:
international
trends
293
Table II. Caries prevalence in preschool children in some countries in Africa
Country Dar es Salaam, Tanzania Ibadan, Nigeria Antananarivo, Madagaskar Ondo, Nigeria
Year
Children (no.1
Age (vr)
96 Caries free x d.m.f.t.
1985
546
5-7
62
1.1
1.9
1983 1986
470
6
70
1.0
-
176
4-6
24
-
5
-
0.8 2.0
;_g
z
6-7
-
1977
1983 Khartoum, Sudan
x d.m.f.s.
1963 1984
affluent parts of the country, have more dental decay than children from lower socioeconomic groups often residing in the rural areas. This is in contrast to the industrialized countries today, but similar to the situation that we had in our country about 60 years ago. A somewhat higher caries prevalence in preschool Tanzanian children is shown in a study carried out by a Finnish team in 3-8 year olds also residing in Dar es’ Salaam (Kerosuo et al., 1988). In this group mean d.m.f.t. was 2.6. Caries experience in general is relatively low in Tanzania today. One of the reasons could be the low consumption of sugar, approximately 6-8 kg per person per year (NBrmark and Mosha, 1989). There is also a national strategy in Tanzania, where the oral health education message to mothers of preschool children is delivered by maternal and child health aids in clinics (Mosha and Robison, 1989). A study by Noah from Ibadan in Nigeria (Noah, 1984) shows an equally low d.m.f.t. value in 6 year olds, as in the study by Mosha and Robison (1989) from Tanzania (Table II). Both studies show a more favourable caries situation for the preschool child in Africa than in South East Asia. On the other hand, it has been shown that if infants have an unfavourable eating pattern, such as prolonged nursing habit, then the mean d.m.f.t. value was 6.8 compared to 1.2 in a group with a favourable eating pattern (Salako, 1985). A study from Madagascar carried out in 1986 (Petersen and Steengard, 1988) shows very high d.m.f.s.values for 4-6 year olds (Table II). In two countries, Sudan and Nigeria, studies on caries prevalence of preschool children have been carried out several years apart, and comparisons have been made (Table Ir) (Emslie, 1966; Ibrahim et al., 1986; Olojugba and Lennon, 1987). In both countries, d.m.f. values of preschool children are increasing. Obviously there are large variations between African countries just as between countries in other parts of the world. Developing countries are often discussed as if they constituted one coherent group of populations with similar trends of health and disease, while in reality the differences in race, religion, culture, economy, diet, hygiene practices, attitudes and behaviour are large, and also have an impact on oral health. The trends for caries prevalence in preschool children in African countries is probably that caries will increase in
10.1
;::
those countries where the economy allows for an increasing sugar consumption and the resources to meet that situation will be scarce. The reason why Beijing 6 year olds have a lot more dental decay than Tanzanian children of about the same age living in Dar es Salaam, is probably that there are differences in dietary patterns, which we know too little about. Neither the traditional Asian nor the traditional African food is really caries promoting, but between-meal eating of sugary foods seems to have become increasingly common in most countries. Even though dietary studies are lacking, the sweet taste might be more common in the Asian food. In one of the studies from Tanzania (Kerosuo et al., 1988) children of both Asian/Arab and African origin were included. The children of Asian/Arab origin had higher d.m.f. values than the African children. The same finding has been reported earlier in a study of Asian and African children in Nairobi (Manji, 1983).
CENTRAL AMERICA In Central America, in Mexico and in Guatemala, similar trends as in the South East of Asia seem to exist, with high d.m.f.t. values in preschool children (Table HZ). Low fluoride concentrations of the drinking water and no dental health education for young children are the explanations offered by the authors of the paper on dental caries prevalence of preschool children in a city in Mexico (Irigoyen et al., 1986). The authors claim that the use of fluoride toothpaste is becoming increasingly common, but as not all children use toothpaste and not all pastes contain fluorides the exposure of the children to fluorides is unclear. In a study from Guatemala, 109 4-6 year old children were examined. Mean d.m.f.t. was 5.4 and only 18 per cent of the children were caries free (Table IIT) (McNulty and Table 111.Caries prevalence in preschool children in Central America
Country
Age furl
% Caries free
x d.m.f.t.
Tepapan, Mexico Guatemala
6-7 4-6
7 18
6.1 5.4
294
J. Dent. 1990; 18: NO. 6
Fos, 1989). In this study, primary teeth were more affected than permanent teeth, which the authors suggested to be an effect of linear hypoplasia in primary teeth due to disturbances during tooth formation. Amore severe caries situation in the primary than in the permanent dentition has been noted in the studies from China, Thailand and Sri Lanka. In a Vietnamese refugee camp in Hong Kong, where the water is artificially fluoridated, the higher caries prevalence in primary than in permanent teeth was very obvious (Holm et al., 1989). Most of the children had lived in the camp in Hong Kong for between 4 and 7 years. The reasons for this difference between primary and permanent dentitions are not obvious. In the paper from Beijing, Wright and coworkers (1989) discuss the possible role of diet, and claim that there may be differences in the diet between younger and older children, younger children having a higher consumption of sweets, soft drinks, etc.
NORTH AMERICA, EUROPE, AUSTRALIA In North America, in several countries in Europe as well as in Australia dental health of preschool children has been investigated on various occasions, and in some of these studies actual comparisons have been made. In Australia, Spencer and co-workers (1989) studied 5-6 year old Melbourne children in 1977 and in 1985. They showed that the number of caries-free children had increased from 10 to 47 per cent and d.m.f.t. decreased from 6.4 to 2.3 (Table IV). Since 1977 the drinking water in Melbourne has been artificially fluoridated, fluoridecontaining toothpastes are widely used and preventive measures are recommended by dental personnel, etc. This situation is similar to that which has been shown in North America and in many countries in Europe. Commonly in those countries where caries in preschool children has been shown to decrease and artificial fluoridation of the drinking water has not been instituted, other resources have been allocated to dental preventive programmes, dental care has been systematic and organized and dental health education has been given. The situation in the European countries is by no means homogeneous. In the Scandinavian countries where all preschool children are included in an organized dental health care system and are seen annually by a dentist, from age 3, the caries situation in young children is fairly well controlled. In other European countries like Poland, Hungary, Spain and Portugal the prevalence of dental caries is still high, but where preventive programmes have been instituted, improvements can be shown. In Hungary the number of caries-free preschool children aged 3-6 had increased from 19 to 25 per cent between 1975 and 1982, and the mean d.m.f.t. decreased from 5.3 to 4.9, thus caries is still prevalent in preschool children (Table Iv) (Hanztly et al., 1985). The slight improvement could be due to a monthly fluoride mouthrinsing programme from 4 to 6 years of age.
Table IV. Changes in caries prevalence in preschool children in Europe and Australia
Counrrv Melbourne, Australia Umed, Sweden Baja, Hungan/
Year of studv
Age (vrl
96 Caries free
1977 1985 1976 1987 1975 1982
5-6 5-6 4 4 3-6 3-6
10 47 36 58 19 25
i d.rn.f.t.
:.: 2:4 A.3” 419
In studies from FR Germany (Pieperet al., 1985; Buhlet 1986), preschool children are shown to have a mean d.m.f.t. of about 3.0. Only 20-30 per cent of the 5 year olds are caries free.In these studies it is pointed out that in spite of the high values reported, there has been and still seems to be a continuous improvement, the yearly incidence being one surface compared to an earlier incidence of four surfaces (Pieperet al., 1985). It is also pointed out that this improvement is based on laborious work with preventive programmes in kindergartens, with fluoride tablet programmes, etc. What seems obvious in both studies is that fillings are only rarely carried out in primary teeth and that most of the decay is left untreated. It is also understood that caries may be more prevalent in preschool children elsewhere in FR Germany. In Sweden, dental caries prevalence has decreased, as in many other countries in Europe and North America, and caries is today uncommon in children below the age of 3. Four-year-old children in the north of Sweden have been included in several epidemiological surveys (Samuelsonet al., 1971; Holm, 1975; Stecksen-Blicksetal., 1985, 1989; A-K Holm, 1976, unpublished results). Fig. 1. shows the results of five cross-sectional studies carried out between 1967 and 1987 in 4 year olds residing in the city of Umea (Steckstn-Blicks et al., 1989). Methods and criteria were the same and bitewing radiographs were used for caries diagnosis. The mean d.m.f.s. values show that the decrease was most pronounced in the beginning of the 1970s and that the curve is now evening out. However, when caries distribution is studied, it seems clear that an increasing percentage of these 4 year olds are totally free from caries or fillings, while the number of al.,
IO j
1967
1971
1976
I980/81
1987
Fig. 7. Mean d.m.f.s. of 4-year-old children in UmeB, Sweden examined over a 20-year period.
Holm: Caries in the preschool
child:
international
trends
295
Irigoyen M., Villanueva R. and de la Teja E. (1986) Dental caries status of of Mexico City. 306-309. Katayama T. and trends of caries
60506 ‘;j 40E 30-0 x e
20IO01 1967
1971
1976
1980
1987
Fig. 2. Proportion of 4-year-old children who are caries free (solid line) or have a d.m.f.s. > 10 over a 20-year period.
children with more than 10 d.m.f.s. does not seem to decrease (Fig. 2). Whether this change in caries distribution is also present in other parts of the country or in other age groups is not known. In the studies referred to, only a few show that the goal set up by WHO for 5-6 year olds has been fulfilled. In the countries where less than 50 per cent of 5-6 year olds have dental caries. this is because they have never experienced that much decay. In no country so far, where caries prevalence has been over 50 per cent in this age group, has it yet been possible to achieve this reduction of dental caries in the preschool child. Let us hope that by the year 2000 the goal can be reached. References Amaratunge _A, Heidmann J. and Jayatilake K. (1986) Oral health in a group of pre-school children attending dental nurse clinics in the Kandy area, Sri Lanka. Community Dent. Health 3, 169-173. Buhl M., Wetzel W-E. and Ehret R. (1986) Epidemiologische Befunde zur Htiufigkeit der Milchzahnkaries bei Kleinkindem. Dtsch. Zahnsrztl. Z. 41, 1038-1042. Emslie R. D. (1966) A dental health survey in the Republic of the Sudan. Br. Dent. J. 120, 167-178. Hanzely B.. Bgn6czy J., Hadas l?. ef al. (1985) Caries prevalence of pre-schoolchildren in Baja, Hungary, in 1975 and 1982: effect of a supervised monthly NaF mouthrinsing program. Community Dent. Oral Epidemiol. 13, 238-240. Holm A-K. (1975) Oral health in 4-year-old Swedish children. Community Dent. Oral Epidemiol. 3,25-33. Holm A-K., Morgan M. V. and Knight J. M. (1989) A dental treatment programme for Vietnamese refugee children in Hong Kong. J. Paediatr. Dent. 5, 21-26. Ibrahim Y. E.. Ghandour I. A. and Udani T. M. (1986) The prevalence of dental caries among urban, semi-urban and rural school children in the Sudan. Odontostomatol. Trop. 9, 157-162.
young children in a suburban community Community Dent. Oral Epidemiol. 14,
Rugg-Gunn A. J. (1986) Epidemiological in Japan (Letters). Br. Dent. J. 160, 229. Kerosuo H., Ngassapa D., Kerosuo E. et al. (1988) Caries experience in the primary dentition of nursery school children in Dar es Salaam, Tanzania. Caries Res. 22, 50-54. Manji F. (1983) The prevalence of dental caries in children of African and Asian origin in Nairobi. Kenya. Odontostomatol. Trop. 1, 27-33. McNulty J. A and Fos P. J. (1989) The study of caries prevalence in children in a developing country. J. Dent. Child. 56, 129-136. Majid Z. A., Nik Hussein N. N. and Meon R. (1987) The oral health of pre-school children in a satellite town in Malaysia. J. Int. Assoc. Dent. Child. 18, 36-40. Mosha R. J. and Robison V. A. (1989) Caries experience of the primary den&ion among groups of Tanzanian urban preschool children. Community Dent. Oral Epidemiol. 17, 34-37. Noah M. 0. (1984) Caries experience and oral cleanliness in the deciduous dentitions of Ibadan children from different social groups. .I. Int. Assoc. Dent. Child. 15, 43-49. Ndrmark S. and Mosha H. J. (1989) Relationship between habits and dental health among rural Tanzanian children. Community Dent. Oral Epidemiol. 17, 317-321. Olojugba 0.0. and Lennon M. A. (1987) Dental caries experience in 5- and 12-year-old school children in Ondo state, Nigeria in 1977 and 1983. Community Dent. Health 4, 129-135. Petersen P. E. and Steengaard M. (1988) Dental caries among urban schoolchildren in Madagascar. Community Dent. Oral Epidemiol. 16, 163-166. Pieper K., Kessler P. and Sirnaitis K. (1985) Kariesbefall. Sanierungsgrad und Mundhygiene bei Kindern im Vorschulalter. Dtsch. Zahn&zfl. Z. 40, 865-868. Salako N. 0. (1985) Infant feeding profile and dental caries status of urban Nigerian children. Acta Odontol. Pediatr. 6, 13-17. Samuelson G., GrahnCn H. and Lindstrdm G. (1971) An epidemiological study of child health and nutrition in a northern Swedish county. V. Oral health studies. Odontol. Revy 22, 189-220. Songpaisan Y. and Davies G. N. (1989) Dental caries experience in the Chiangmai/Lamphun provinces of Thailand. Community Dent. Oral Epidemiol. 17, 131-135. Spencer A. J., Wright F. A C., Brown L. M. et al. (1989) Changing caries experience and risk factors in five- and six-year-old Melbourne children. Aust. Dent. J. 34, 160-165. StecksCn-Blicks C., Arvidsson S. and Holm A-K. (1985) Dental health, dental care, and dietary habits in children in different parts of Sweden. Acta Odontol. Stand. 43, 59-67. StecksCn-Blicks C., Holm A-K. and Mayanagi H. (1989) Dental caries in Swedish 4-year-old children. Changes between 1967 and 1987. Swed. Dent. J. 13,39-44. WHO (1987) Oral Health Surveys. Basic Methods, 3rd edn. Geneva, WHO. Wright F. A. C., Deng H. and Shi S-T. (1989) The dental health status of 6- and 12 year-old Beijing schoolchildren in 1987. Community Dent. Health 6, 121-130.
18: 291-295
291
Caries in the preschool international trends
child:
A-K. Holm Department
of Pedodontics,
University
of Ume& Sweden
ABSTRACT Most studies on the prevalence and incidence of dental caries are carried out on schoolchildren and data on preschool children are comparably few. In most of the developing countries in South East Asia, children have a high prevalence of dental caries in the primary dentition, often in contrast to the situation in the permanent dentition. The reasons for this difference are not obvious, but may be linked to differences in diet. In Africa, dental caries prevalence in the preschool child seems to be increasing somewhat in countries or parts of countries where there is an increase in sugar intake, while it stays low in countries where a poor economy restricts sugar intake. The prevalence does not seem to be as high as in South East Asia. In most industrialized countries in northern Europe, in North America, in Australia and New Zealand, dental caries is decreasing, often linked to an increasing use of fluorides, to various types of dental health education programmes, etc. In many European countries, the prevalence in preschool children is, however, still high and caries in primary teeth is often left untreated. In Scandinavia, where all preschool children are included in an organized dental care programme, dental caries has been decreasing markedly during the 1970s and at the beginning of the 1980s. While the mean values for d.m.f.t. at present appear to be largely unchanged, there seems to be a change in the distribution of the disease. More and more children are totally free of the disease, while the group with high d.m.f. values has a tendency to increase. KEY WORDS:
Dental caries, Preschool child, Trends
J. Dent. 1990; 18: 29 l-295 (Presented at ‘Caries and the Preschool Child’, a symposium Society, 22 May 1990, London, UK.) Correspondence should be addressed S-901 87 Ume& Sweden.
ro: Professor A-K. Holm, Department
Over the past decade, the decreasing caries incidence in children has been documented in several studies. Most of them have dealt with children in the industrialized countries, where the decline in dental caries, with a few exceptions, is indisputable. Most authors seem to agree that the widespread use of fluorides is the main reason for the decline in dental caries, but that other factors like improved oral hygiene and changes in eating patterns have had an impact. The dental health of the preschool child has not nearly been documented to the same extent as the dental health of schoolchildren. This is probably because primary teeth in many countries still are not considered to be as important or as valuable as permanent teeth, and also because in many of the developing countries, the older children may be going to school and are easier to identify and include in oral health surveys. One of the goals set by WHO for Oral Health by the 0 1990 Butterworth-Heinemann 0300-57 12/90/06029 I-05
Ltd.
of the British Paedodontic
of Pedodontics,
University
of Ume&
Year 2000, is for 50 per cent of the 5-6 year olds to be totally free from dental caries. This seems to be a rather modest goal, but there are many countries where it still appears very remote. What is the caries situation of the preschool child today in countries that lie outside Great Britain, and can we discern any trends in the disease pattern? As was mentioned earlier, data on preschool children are rather limited, but some studies have been published in recent years. In the majority of the studies to which I will be referring, WHO methods and criteria have been used in the diagnosis of dental caries (WHO, 1987).
SOUTH
EAST ASIA
Data on dental health of preschool children in South East Asia are sparse. One study has, however, recently been
292
J. Dent. 1990; 18: No. 6
Table1. Caries prevalence in preschool children in some countries in South East Asia Children
Year
Age
(no.)
hfr)
Beijing, China Kandy, Sri Lanka Malaysia
1987 1984 1986
120 280 509
6 ;I:
Thailand
1986
599
5-6
Country
published on the dental health of 6 and 12 year olds in the city of Beijing (Table I). The study was carried out by a team of Australian and Chinese dentists (Wright et al., 1989) and includes 100 children in each age group. There is a striking difference in caries prevalence between the groups. While only 5 per cent of the 6 year olds are caries free, the corresponding figure for the 12 year olds is 54 per cent. The 6 year olds had a mean d.m.f.t. of 6.3 and a mean d.m.f.s. of 12.0.The d-component was close to 80 per cent. These children resided in a central area of Beijing, and their dental awareness may be higher than average. Thus, 74 per cent said that they used a toothbrush to clean their teeth. In Sri Lanka, preschool and school children are given dental care by dental nurses after the New Zealand model, however, there is only one nurse per 30000 children. A survey of the dental health of 3-5 year olds, carried out in 1984 (Amaratunge et al., 1986), showed a very serious caries situation with 90 per cent of 3 year olds affected by dental caries and d.m.f.s. values of the 5 year olds close to 11 (Table I). Between 50 and 60 per cent of 3-5 year olds had carious incisors. According to the authors, a team of Danish and Sri Lankan dentists, the nurses are overwhelmed by the size of the treatment needs. The authors are not inclined to say anything definite about the trends in dental health in preschool children, but point towards the fact that the 3 year olds had a higher caries prevalence than the 5 year olds. They explain the rapid, rather uncontrolled caries in the primary dentition to be due at least partly to the increased consumption of refined sugar-containing snacks in the urban areas of Sri Lanka during the last decade. In Malaysia, children between 3 and 6 years of age, selected from private schools, were caries free in 21 per cent and had a mean d.m.f.t. of 5.4 (Table Z) (Majid et al., 1987). Rampant caries was found in 16 per cent of the children. There are no previous data in preschool children to compare with, but the authors, a team from the dental faculty of Kuala Lumpur, consider caries to be increasing, and blame the situation on easy access to confectionary and soft drinks. Thailand has a highly developed system of primary health care. In an extensive survey from 1986 (Songpaisan and Davies, 1989),including both children and acults, the preschool children amounted to 600. These children showed large variations in their caries experience, for reasons that are not really given (Table I). The most
% Caries
free 5 :y 9-39
x d.rn.f.t. x d.m.f.s. ::: ;::-8.2
12.0 11.0 -
conspicuous feature was a low caries prevalence in the permanent dentition compared to a much higher prevalence in the primary dentition. There is some speculation in the paper about the possibility of the children included being undernourished, this in turn predisposing to linear enamel hypoplasias which in turn would increase the risk of dental caries, however the diet of the children is not mentioned. If China, Sri Lanka, Malaysia and Thailand are taken to represent four countries in the south-east of Asia, where resources for dental care to preschool children are, or have been, very limited, then the situation in Japan ought to be of interest. In this highly industralized country there are 29 dental schools and a high dentist to population ratio. Dental caries is, however, still very prevalent in Japan. According to a short note published by Katayama and Rugg-Gunn in 1986, there has been no decline in dental caries prevalence in Japan comparable to that recorded in other industrialized countries. In 1981, the d.m.f.t. at the age of 5 was 8.2, a lower value, however, than in 1975. According to the Ministry of Health & Welfare in Japan, 66.7 per cent of 3 year olds had dental caries in 1987 compared to 72.4 per cent in 1981, indicating an improvement (Noda T., 1990,personal communication). The main reasons for the high caries prevalence in Japan are probably a fairly high sugar consumption in combination with a restricted use of fluorides. The discernible trend in the dental caries prevalence of preschool children in South East Asia seems to be that dental caries is increasing.
AFRICA The caries situation in many African countries is different from that found in South East Asia. In Tanzania, one of the countries where several epidemiological surveys have been performed, lately data on preschool children have also been published. Mosha and Robison (1989) showed in a study performed in 1985 that 5-7 year olds, all residing in Dar es Salaam, had a d.m.f.t. of 1.1 (Table II). Sixty-two per cent were caries free. The figures should be regarded as maximum figures, as the children were all selected from nursery schools, where children are likely to have a higher socioeconomic background than children who do not attend. In developing countries, children from higher socioeconomic groups, often residing in the urban more
Holm: Caries in the preschool
child:
international
trends
293
Table II. Caries prevalence in preschool children in some countries in Africa
Country Dar es Salaam, Tanzania Ibadan, Nigeria Antananarivo, Madagaskar Ondo, Nigeria
Year
Children (no.1
Age (vr)
96 Caries free x d.m.f.t.
1985
546
5-7
62
1.1
1.9
1983 1986
470
6
70
1.0
-
176
4-6
24
-
5
-
0.8 2.0
;_g
z
6-7
-
1977
1983 Khartoum, Sudan
x d.m.f.s.
1963 1984
affluent parts of the country, have more dental decay than children from lower socioeconomic groups often residing in the rural areas. This is in contrast to the industrialized countries today, but similar to the situation that we had in our country about 60 years ago. A somewhat higher caries prevalence in preschool Tanzanian children is shown in a study carried out by a Finnish team in 3-8 year olds also residing in Dar es’ Salaam (Kerosuo et al., 1988). In this group mean d.m.f.t. was 2.6. Caries experience in general is relatively low in Tanzania today. One of the reasons could be the low consumption of sugar, approximately 6-8 kg per person per year (NBrmark and Mosha, 1989). There is also a national strategy in Tanzania, where the oral health education message to mothers of preschool children is delivered by maternal and child health aids in clinics (Mosha and Robison, 1989). A study by Noah from Ibadan in Nigeria (Noah, 1984) shows an equally low d.m.f.t. value in 6 year olds, as in the study by Mosha and Robison (1989) from Tanzania (Table II). Both studies show a more favourable caries situation for the preschool child in Africa than in South East Asia. On the other hand, it has been shown that if infants have an unfavourable eating pattern, such as prolonged nursing habit, then the mean d.m.f.t. value was 6.8 compared to 1.2 in a group with a favourable eating pattern (Salako, 1985). A study from Madagascar carried out in 1986 (Petersen and Steengard, 1988) shows very high d.m.f.s.values for 4-6 year olds (Table II). In two countries, Sudan and Nigeria, studies on caries prevalence of preschool children have been carried out several years apart, and comparisons have been made (Table Ir) (Emslie, 1966; Ibrahim et al., 1986; Olojugba and Lennon, 1987). In both countries, d.m.f. values of preschool children are increasing. Obviously there are large variations between African countries just as between countries in other parts of the world. Developing countries are often discussed as if they constituted one coherent group of populations with similar trends of health and disease, while in reality the differences in race, religion, culture, economy, diet, hygiene practices, attitudes and behaviour are large, and also have an impact on oral health. The trends for caries prevalence in preschool children in African countries is probably that caries will increase in
10.1
;::
those countries where the economy allows for an increasing sugar consumption and the resources to meet that situation will be scarce. The reason why Beijing 6 year olds have a lot more dental decay than Tanzanian children of about the same age living in Dar es Salaam, is probably that there are differences in dietary patterns, which we know too little about. Neither the traditional Asian nor the traditional African food is really caries promoting, but between-meal eating of sugary foods seems to have become increasingly common in most countries. Even though dietary studies are lacking, the sweet taste might be more common in the Asian food. In one of the studies from Tanzania (Kerosuo et al., 1988) children of both Asian/Arab and African origin were included. The children of Asian/Arab origin had higher d.m.f. values than the African children. The same finding has been reported earlier in a study of Asian and African children in Nairobi (Manji, 1983).
CENTRAL AMERICA In Central America, in Mexico and in Guatemala, similar trends as in the South East of Asia seem to exist, with high d.m.f.t. values in preschool children (Table HZ). Low fluoride concentrations of the drinking water and no dental health education for young children are the explanations offered by the authors of the paper on dental caries prevalence of preschool children in a city in Mexico (Irigoyen et al., 1986). The authors claim that the use of fluoride toothpaste is becoming increasingly common, but as not all children use toothpaste and not all pastes contain fluorides the exposure of the children to fluorides is unclear. In a study from Guatemala, 109 4-6 year old children were examined. Mean d.m.f.t. was 5.4 and only 18 per cent of the children were caries free (Table IIT) (McNulty and Table 111.Caries prevalence in preschool children in Central America
Country
Age furl
% Caries free
x d.m.f.t.
Tepapan, Mexico Guatemala
6-7 4-6
7 18
6.1 5.4
294
J. Dent. 1990; 18: NO. 6
Fos, 1989). In this study, primary teeth were more affected than permanent teeth, which the authors suggested to be an effect of linear hypoplasia in primary teeth due to disturbances during tooth formation. Amore severe caries situation in the primary than in the permanent dentition has been noted in the studies from China, Thailand and Sri Lanka. In a Vietnamese refugee camp in Hong Kong, where the water is artificially fluoridated, the higher caries prevalence in primary than in permanent teeth was very obvious (Holm et al., 1989). Most of the children had lived in the camp in Hong Kong for between 4 and 7 years. The reasons for this difference between primary and permanent dentitions are not obvious. In the paper from Beijing, Wright and coworkers (1989) discuss the possible role of diet, and claim that there may be differences in the diet between younger and older children, younger children having a higher consumption of sweets, soft drinks, etc.
NORTH AMERICA, EUROPE, AUSTRALIA In North America, in several countries in Europe as well as in Australia dental health of preschool children has been investigated on various occasions, and in some of these studies actual comparisons have been made. In Australia, Spencer and co-workers (1989) studied 5-6 year old Melbourne children in 1977 and in 1985. They showed that the number of caries-free children had increased from 10 to 47 per cent and d.m.f.t. decreased from 6.4 to 2.3 (Table IV). Since 1977 the drinking water in Melbourne has been artificially fluoridated, fluoridecontaining toothpastes are widely used and preventive measures are recommended by dental personnel, etc. This situation is similar to that which has been shown in North America and in many countries in Europe. Commonly in those countries where caries in preschool children has been shown to decrease and artificial fluoridation of the drinking water has not been instituted, other resources have been allocated to dental preventive programmes, dental care has been systematic and organized and dental health education has been given. The situation in the European countries is by no means homogeneous. In the Scandinavian countries where all preschool children are included in an organized dental health care system and are seen annually by a dentist, from age 3, the caries situation in young children is fairly well controlled. In other European countries like Poland, Hungary, Spain and Portugal the prevalence of dental caries is still high, but where preventive programmes have been instituted, improvements can be shown. In Hungary the number of caries-free preschool children aged 3-6 had increased from 19 to 25 per cent between 1975 and 1982, and the mean d.m.f.t. decreased from 5.3 to 4.9, thus caries is still prevalent in preschool children (Table Iv) (Hanztly et al., 1985). The slight improvement could be due to a monthly fluoride mouthrinsing programme from 4 to 6 years of age.
Table IV. Changes in caries prevalence in preschool children in Europe and Australia
Counrrv Melbourne, Australia Umed, Sweden Baja, Hungan/
Year of studv
Age (vrl
96 Caries free
1977 1985 1976 1987 1975 1982
5-6 5-6 4 4 3-6 3-6
10 47 36 58 19 25
i d.rn.f.t.
:.: 2:4 A.3” 419
In studies from FR Germany (Pieperet al., 1985; Buhlet 1986), preschool children are shown to have a mean d.m.f.t. of about 3.0. Only 20-30 per cent of the 5 year olds are caries free.In these studies it is pointed out that in spite of the high values reported, there has been and still seems to be a continuous improvement, the yearly incidence being one surface compared to an earlier incidence of four surfaces (Pieperet al., 1985). It is also pointed out that this improvement is based on laborious work with preventive programmes in kindergartens, with fluoride tablet programmes, etc. What seems obvious in both studies is that fillings are only rarely carried out in primary teeth and that most of the decay is left untreated. It is also understood that caries may be more prevalent in preschool children elsewhere in FR Germany. In Sweden, dental caries prevalence has decreased, as in many other countries in Europe and North America, and caries is today uncommon in children below the age of 3. Four-year-old children in the north of Sweden have been included in several epidemiological surveys (Samuelsonet al., 1971; Holm, 1975; Stecksen-Blicksetal., 1985, 1989; A-K Holm, 1976, unpublished results). Fig. 1. shows the results of five cross-sectional studies carried out between 1967 and 1987 in 4 year olds residing in the city of Umea (Steckstn-Blicks et al., 1989). Methods and criteria were the same and bitewing radiographs were used for caries diagnosis. The mean d.m.f.s. values show that the decrease was most pronounced in the beginning of the 1970s and that the curve is now evening out. However, when caries distribution is studied, it seems clear that an increasing percentage of these 4 year olds are totally free from caries or fillings, while the number of al.,
IO j
1967
1971
1976
I980/81
1987
Fig. 7. Mean d.m.f.s. of 4-year-old children in UmeB, Sweden examined over a 20-year period.
Holm: Caries in the preschool
child:
international
trends
295
Irigoyen M., Villanueva R. and de la Teja E. (1986) Dental caries status of of Mexico City. 306-309. Katayama T. and trends of caries
60506 ‘;j 40E 30-0 x e
20IO01 1967
1971
1976
1980
1987
Fig. 2. Proportion of 4-year-old children who are caries free (solid line) or have a d.m.f.s. > 10 over a 20-year period.
children with more than 10 d.m.f.s. does not seem to decrease (Fig. 2). Whether this change in caries distribution is also present in other parts of the country or in other age groups is not known. In the studies referred to, only a few show that the goal set up by WHO for 5-6 year olds has been fulfilled. In the countries where less than 50 per cent of 5-6 year olds have dental caries. this is because they have never experienced that much decay. In no country so far, where caries prevalence has been over 50 per cent in this age group, has it yet been possible to achieve this reduction of dental caries in the preschool child. Let us hope that by the year 2000 the goal can be reached. References Amaratunge _A, Heidmann J. and Jayatilake K. (1986) Oral health in a group of pre-school children attending dental nurse clinics in the Kandy area, Sri Lanka. Community Dent. Health 3, 169-173. Buhl M., Wetzel W-E. and Ehret R. (1986) Epidemiologische Befunde zur Htiufigkeit der Milchzahnkaries bei Kleinkindem. Dtsch. Zahnsrztl. Z. 41, 1038-1042. Emslie R. D. (1966) A dental health survey in the Republic of the Sudan. Br. Dent. J. 120, 167-178. Hanzely B.. Bgn6czy J., Hadas l?. ef al. (1985) Caries prevalence of pre-schoolchildren in Baja, Hungary, in 1975 and 1982: effect of a supervised monthly NaF mouthrinsing program. Community Dent. Oral Epidemiol. 13, 238-240. Holm A-K. (1975) Oral health in 4-year-old Swedish children. Community Dent. Oral Epidemiol. 3,25-33. Holm A-K., Morgan M. V. and Knight J. M. (1989) A dental treatment programme for Vietnamese refugee children in Hong Kong. J. Paediatr. Dent. 5, 21-26. Ibrahim Y. E.. Ghandour I. A. and Udani T. M. (1986) The prevalence of dental caries among urban, semi-urban and rural school children in the Sudan. Odontostomatol. Trop. 9, 157-162.
young children in a suburban community Community Dent. Oral Epidemiol. 14,
Rugg-Gunn A. J. (1986) Epidemiological in Japan (Letters). Br. Dent. J. 160, 229. Kerosuo H., Ngassapa D., Kerosuo E. et al. (1988) Caries experience in the primary dentition of nursery school children in Dar es Salaam, Tanzania. Caries Res. 22, 50-54. Manji F. (1983) The prevalence of dental caries in children of African and Asian origin in Nairobi. Kenya. Odontostomatol. Trop. 1, 27-33. McNulty J. A and Fos P. J. (1989) The study of caries prevalence in children in a developing country. J. Dent. Child. 56, 129-136. Majid Z. A., Nik Hussein N. N. and Meon R. (1987) The oral health of pre-school children in a satellite town in Malaysia. J. Int. Assoc. Dent. Child. 18, 36-40. Mosha R. J. and Robison V. A. (1989) Caries experience of the primary den&ion among groups of Tanzanian urban preschool children. Community Dent. Oral Epidemiol. 17, 34-37. Noah M. 0. (1984) Caries experience and oral cleanliness in the deciduous dentitions of Ibadan children from different social groups. .I. Int. Assoc. Dent. Child. 15, 43-49. Ndrmark S. and Mosha H. J. (1989) Relationship between habits and dental health among rural Tanzanian children. Community Dent. Oral Epidemiol. 17, 317-321. Olojugba 0.0. and Lennon M. A. (1987) Dental caries experience in 5- and 12-year-old school children in Ondo state, Nigeria in 1977 and 1983. Community Dent. Health 4, 129-135. Petersen P. E. and Steengaard M. (1988) Dental caries among urban schoolchildren in Madagascar. Community Dent. Oral Epidemiol. 16, 163-166. Pieper K., Kessler P. and Sirnaitis K. (1985) Kariesbefall. Sanierungsgrad und Mundhygiene bei Kindern im Vorschulalter. Dtsch. Zahn&zfl. Z. 40, 865-868. Salako N. 0. (1985) Infant feeding profile and dental caries status of urban Nigerian children. Acta Odontol. Pediatr. 6, 13-17. Samuelson G., GrahnCn H. and Lindstrdm G. (1971) An epidemiological study of child health and nutrition in a northern Swedish county. V. Oral health studies. Odontol. Revy 22, 189-220. Songpaisan Y. and Davies G. N. (1989) Dental caries experience in the Chiangmai/Lamphun provinces of Thailand. Community Dent. Oral Epidemiol. 17, 131-135. Spencer A. J., Wright F. A C., Brown L. M. et al. (1989) Changing caries experience and risk factors in five- and six-year-old Melbourne children. Aust. Dent. J. 34, 160-165. StecksCn-Blicks C., Arvidsson S. and Holm A-K. (1985) Dental health, dental care, and dietary habits in children in different parts of Sweden. Acta Odontol. Stand. 43, 59-67. StecksCn-Blicks C., Holm A-K. and Mayanagi H. (1989) Dental caries in Swedish 4-year-old children. Changes between 1967 and 1987. Swed. Dent. J. 13,39-44. WHO (1987) Oral Health Surveys. Basic Methods, 3rd edn. Geneva, WHO. Wright F. A. C., Deng H. and Shi S-T. (1989) The dental health status of 6- and 12 year-old Beijing schoolchildren in 1987. Community Dent. Health 6, 121-130.
