Caries prevalence in Icelandic children in 1970 and 1983

Prevalence of dental erosion in children: a national survey

OBJECTIVES

To measure the prevalence of dental erosion in permanent teeth in Iceland as part of the National Oral Health Survey.

METHODS

A representative, nationwide sample of 2251 Icelandic children, 20% of those aged 6, 12 and 15 year, was examined. Dental erosion was recorded for all erupted permanent teeth and graded using the modified scale of Lussi.

RESULTS

Erosion was not seen in the permanent teeth of six-year-olds, but was present in 15.7% of 12-year-olds, more frequently in boys than girls (19.9% boys, 11.0% girls; P < 0.001). Among 15-year-olds, dental erosion was seen among 30.7% of subjects (38.3% boys, 22.7% girls; P < 0.001). Severity of erosion was mostly scored as grade I, with only 5.5% of 15-year-olds scored as grade II, mostly on tooth 46 (4.3%) and 36 (4.2%). For 12-year-olds, 0.9% had erosion scores of grade II mostly on tooth 46 (0.8%) and 36 (0.7%). No subjects had erosion of grade III. The most common clinical manifestation of erosion was the appearance of cup-like lesions on the cusps of lower first molars.

CONCLUSIONS

Dental erosion was frequently present by the age of 12; the prevalence doubled by age 15 and was seen almost twice as often among boys than girls. Teeth most frequently showing signs of erosion were the lower first molars. The rapidly growing prevalence of erosion demonstrated by this nationwide survey emphasizes the need for further research into the aetiology of erosion and possible methods of preventing and treating this emerging dental problem.

Caries prevalence of permanent teeth: a national survey of children in Iceland using ICDAS

OBJECTIVES

The Icelandic Oral Health Survey aimed to obtain new national data on the oral health of Icelandic children and teenagers.

METHODS

A representative stratified random cluster sample of 2251 Icelandic children in first, seventh and 10th grade, aged approximately 6-, 12- and 15-years old was examined for caries prevalence using the ICDAS criteria. Bite-wing digital radiographs were obtained for the children in 7th and 10th grade.

RESULTS

D(3)MFT scores by visual examination of 6-, 12- and 15-year olds were 0.12, 1.43 and 2.78 respectively but when including radiographs, the D(3)MFT rose to 2.11 at 12 years and 4.25 at 15 years. The Significant Caries Index, SiC, by visual examination for 12 and 15 y was 3.7 and 6.7 respectively but was 4.7 for 12 y and 8.9 for 15 y with radiographs. In all age groups and at most disease levels, caries was active in the majority of the lesions (58-100%). The percentage of children with no visually detectable caries at D(3)/D(1) level was 93%/74% for 6 years, 48%/22% for 12 years and 35%/16% for 15 years. When radiographs were included the percentage reduced to 34%/15% for 12 years and 20%/6% for 15 years. Approximately 80% of 12- and 15-year-olds had at least one of their first molars sealed, with the mean number of sealed first molars being 2.2 among 12 y and 2.0 among 15 y.

CONCLUSIONS

Caries levels were higher than expected in this national survey and further away from the goals of the National Health Plan for 2010 than anticipated. Caries distribution was skewed with more than half of the children having low caries scores but a wide distribution of caries experience was seen among the remaining population.

Trends in dental health among Icelandic urban children

Caries experience, oral hygiene and caries-related salivary parameters were recorded in a 20% representative sample of 12-year-old schoolchildren in Reykjavik, Iceland in 1991. The majority of the children was re-examined 3 years later in 1994. Trends in prevalence of caries and salivary bacteria were assessed by comparison with an analogous earlier longitudinal study (1984-87). Mean DFS values for 12-year-olds were 12.1 and 4.1, for 15-year-olds 23.3 and 11.3 in the earlier and later study, respectively. Reduction in DFS was 66% and 52% for the respective age groups. The decline was most pronounced in the group with low caries prevalence. Trends in caries experience were paralleled by salivary bacteria. The mean caries scores and frequency distributions of 15-year-olds in 1994 closely resembled those of 12-year-olds a decade earlier, suggesting a delay rather than a true fall in caries prevalence.

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

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.

Prevalence of gingivitis in 6-year-olds in Reykjavik, Iceland

As part of a wider investigation of malocclusion, the aim of this study was to determine the prevalence of gingivitis in 6-year-olds in Reykjavik. Parents and guardians of the 401 children in 8 schools were invited by letter to have their children take part. There were 230 positive replies (57%). The Gingival Bleeding Index was used to determine the condition of the gingiva on mesiobuccal and buccal surfaces of 6 selected teeth (totaling 12 surfaces). The results showed that 26% had healthy gingivae, 23% showed bleeding from one surface, 20% from two, 17% from three, and 15% from four to eight surfaces. There were no statistically significant differences in the number of bleeding surfaces between boys and girls. The mean GBI for the whole group was 16%. Gingivitis in this group was therefore prevalent but usually slight.

Restoring oral health. On the rise and fall of dental caries in Iceland

During the last decade, a continuous decrease in dental caries has been observed among schoolchildren in Iceland. In this paper, various epidemiological studies have been reviewed and summarized to illustrate caries prevalence, and how it has changed during the last decades. Furthermore, an attempt has been made to describe some of the factors involved and their possible effects on caries disease. During this period, sugar consumption increased, especially in the form of sweets and soft drinks. At the same time, the import of toothpaste increased, and preventive measures such as fissure sealants and fluoride rinsing programs were intensified. Other factors likely to have had an impact were changes in treatment philosophy and increased personnel resources. There does not seem to be any single factor responsible for the onset of the caries decline. It rather looks as if this was a multifactorial effect due to a number of different preventive measures. During recent years, a change in treatment philosophy, the evident increase in fluoride toothpaste consumption, and possible changes in the oral microbial flora, together with the use of fluoride varnishes, sealants, and increased manpower, may explain the decline.

Longitudinal study of caries, cariogenic bacteria and diet in children just before and after starting school

Fifty 5-yr-old preschool children living in Akranes, a small community in West Iceland known to have a high caries prevalence, were investigated with respect to caries, salivary counts of mutans streptococci and lactobacilli, and consumption of cariogenic foods. Fifteen months later, after being in school for half a year, 43 of the 50 children were reexamined and investigated as before. Mean dmfs scores rose from 7.1 to 9.0, but the scores including initial caries rose from 9.7 to 15.3. Mutans streptococci were carried by 84% of children on both occasions with a mean count 2.1 and 3.6 x 10(5) cfu/ml. Lactobacillus carriage increased from 29 to 38% and the mean count from 5.1 to 13 x 10(3) cfu/ml at 6 yr. The frequency of consumption of sugar-containing foods increased from 4.2 to 5.2 intakes per day and between-meal snacks rose from 3.0 to 3.7 per day. Children classified as "misusing" sugar were 59% at 5 yr and 83% at 6 yr. The mean caries score at 6 yr for children "misusing" sugar was 10.7 but only 2.0 for those not misusing sugar. Thus the deterioration in dental health appears, in these children, to be associated with the increased consumption of sweets and other cariogenic between-meal snacks after starting school.

Caries experience in Icelandic 12-year-old urban children between 1984 and 1991

In order to evaluate trends in caries experience, a 20% random sample of 12-yr-old residents of Reykjavik, Iceland (252 children) was examined clinically and radiographically in 1991 under conditions consistent with those of the survey conducted in 1984. In addition to caries data, frequency of toothbrushing and use of fluoride dentifrice were recorded. The mean DFT and DFS were 3.0 and 4.1, respectively. The decrease in caries experience reached 60% with an annual fall in DFS of nearly 10%. During the 7-yr period between examinations the decline in DFT and DFS scores averaged 5.2 and 8, respectively, the annual reduction amounting to 0.7 DF teeth or 1.1 DF surfaces per child. The ratio of approximal/occlusal caries and the proportion of approximal caries were similar in both surveys. Fourteen percent of the children were free from manifest caries in 1991, but only 2% in 1984. Polarization between low and high prevalence individuals had intensified. Ninety-five percent of the children brushed their teeth regularly and 97% reported using a fluoride dentifrice.

Dental caries and Streptococcus mutans in a rural child population in Iceland

In spite of having a high socioeconomic standing, in Iceland caries prevalence has remained stubbornly high. This study reports findings from a mixed fishing and farming community in East Iceland that has traditionally been associated with the highest prevalence of caries. A total of 188 children aged 3-16 yr (96.4% of residents of that age group) were examined. At 6 yr the mean dmfs score was 4.1, DMFS 0 and 48% were caries-free. The mean DMFS score at 12 yr was 4.7 and 22.6% remained caries-free but at 16 yr the DMFS score was 11.6 and no children were caries-free. Caries was unevenly distributed within each age group and was more prevalent among residents of the fishing town than the surrounding farming district. In a pilot study conducted in 1989 mean counts of Streptococcus mutans for children aged 4-7 yr were 2.6 x 10(5) cfu/ml and declined to 4.6 x 10(4) cfu/ml in 1990 after a program of chlorhexidine brushing had been added to the routine caries preventive measures adopted in this community. It may therefore be possible to screen Icelandic children for caries risk and apply preventive measures to those demonstrated to be most in need.

Caries prevalence, Streptococcus mutans and sugar intake among 4-year-old urban children in Iceland

Concern at the high prevalence of dental caries in Iceland prompted this survey of 158 preschool children in Reykjavik. On initial examination in 1987 45.8% of the children were caries-free and the prevalence of caries was a mean dmft 2.4 and a mean dmfs 3.3. A dietary questionnaire aimed at discovering the frequency of sugar consumption per week revealed a threshold value of 30 instances of sugar intake per week above which caries prevalence increased markedly. Some of this sugar is consumed in paediatric medicines, particularly antibiotics and anti-asthmatics, which are widely used in Iceland. Caries prevalence (dmft) for children taking such medicines regularly was 3.0 compared with 2.1 for remaining children (P less than 0.05). Those children who took fluoride tablets regularly had less caries (mean dmft 1.1) than those who used fluoride tablets irregularly or not at all (mean dmft 2.8; P less than 0.001). Samples of saliva from the dorsum of the tongue were taken for determination of numbers of Streptococcus mutans and lactobacilli. High bacterial counts were strongly associated with caries. Only 5% of children with more than 5 x 10(5 S. mutans cfu per ml were caries free but 27% of subjects had 67% of the total amount of caries for the group and all of these would have been detected by the bacterial test.

Sugar consumption and caries experience in 12- and 13-year-old Icelandic children

Dietary habits with regard to sugar consumption and caries experience were studied in a group of 275 Icelandic children aged 12 and 13 years. The pattern of meals and sugar-containing food intake frequency were assessed by means of a dietary questionnaire. All dental examinations were performed by one examiner, using standardized methods and diagnostic criteria. Only 75% of the children had three regular meals daily. Breakfast and lunch were the most frequently omitted meals. Sweet buns were consumed by 32% of the children with meals and by 58% between meals, whereas soft drinks were consumed by 42% and 46%, respectively. Eighty-three per cent of the children reported eating sweets daily. The most popular products included confectionery, buns, cakes, and soft drinks, which constituted 53% of the intake with meals and 68% of that between meals. A higher caries incidence was associated with frequent intake of buns and cakes with meals and confectionery.

Secretor status and dental caries in Iceland

The proportion of non-secretors of ABH blood-group substances among Icelanders is one of the highest recorded for European countries. Dental caries prevalence is also very high. In this study of dental caries in young adults mean number of decayed, missing and filled teeth for secretors were 17.4 and for non-secretors 19.9 (P less than 0.05). A majority of patients seeking free dental treatment in the Dental School were non-secretors (62.7%) significantly more than the proportion of non-secretors in the general population (36%; P less than 0.01). It is postulated that blood group substances may interfere with the adherence of Streptococcus mutans to teeth.

The pre- and posteruptive effects of fluoride in the caries decline

The widespread availability of fluoride from many sources is accepted as a major reason for the caries decline among children in developed countries. There is still controversy, however, about its principal mode of action. This article reviews the evidence on fluoride's preeruptive and posteruptive effects, and suggests reasons for its continuing role in the caries decline. Early fluoridation studies accepted that fluoride acted preruptively through incorporation into developing enamel; but further research could not explain why fluoride levels were not clearly higher in enamel exposed to fluoride, nor why there were no clear correlations between caries experience and enamel fluoride concentration. Instead, considerable evidence suggests that fluoride acts mainly, though not entirely, through posteruptive remineralization of demineralized enamel. Caries experience has declined in nonfluoridated as well as in fluoridated areas, though DMF scores are still consistently lower in fluoridated areas. Posteruptive remineralization effects are seen from fluoridated drinking water as well as with fluoride from other sources. The continuing caries decline, beyond the level suggested by early fluoridation field trials, can be attributed either to more efficient remineralization or to long-term, intraoral ecological change, or to both.

Mutans streptococci, lactobacilli and caries prevalence in 11- and 12-year-old Icelandic children

Since the caries prevalence has not declined in Iceland as it has in other European countries, it was of interest to study the presence of cariogenic bacteria in Icelandic children. The prevalence of salivary mutans streptococci and lactobacilli was examined in 217 11- and 12-yr-old Icelandic children and was related to their caries prevalence. In 2% of the children mutans streptococci were not found whereas 31% and 35% of the 11-yr-olds and 12-yr-olds respectively carried more than 10(6) CFU per ml saliva. Lactobacilli were not detected in 8% of the children whereas 28% of the 11-yr-olds and 23% of the 12-yr-olds had more than 10(5) CFU per ml saliva. The mean caries prevalence (DFS), initial caries included, for 11-yr-olds was 21.6 and for 12-yr-olds 28.8. Both mutans streptococci and lactobacilli were significantly correlated to each other as well as to caries prevalence. An increased number of these microorganisms, especially the mutans streptococci, were associated with an increased DFS. Children with high salivary counts of mutans streptococci and lactobacilli showed four times higher DFS than children with low numbers. The magnitude of salivary cariogenic bacteria as well as caries prevalence was found to resemble the situation in Sweden 10 yr ago. S. mutans (serotype c/e/f) was carried by all mutans streptococci positive children. S. sobrinus (serotype d/g) was found in 60 children (30.2%). Children with both S. mutans and S. sobrinus had significantly higher salivary counts of mutans streptococci and lactobacilli as well as caries prevalence than children with only S. mutans.

Dental health in Icelandic urban children aged 11 and 12 years

A total of 1370 children were examined for caries, gingivitis, periodontal pocketing, calculus and loss of marginal alveolar bone. The mean DFT and DFS scores were 6.2 and 8.7 for 11-yr-old children and 8.2 and 12.1 for 12-yr-olds. The average number of initial caries lesions was 12.4 among 11-yr-olds and 15.7 among 12-yr-olds. The proximal and smooth surfaces accounted for 37% of the total DFS score in the 11-yr-old children and 43% in the 12-yr-olds. The median DFS score for the 11-yr-old boys and girls was 7, while for the 12-yr-old boys it was 9 and for the girls 11. Only 1.8% of the children were free from caries. The occurrence of gingivitis, expressed by GBI, was 20 in both age groups. 8% of the children showed no advanced gingival inflammation, while less than 1% had bleeding gingivitis at all examined surfaces. Supragingival calculus was found in 10% of the children. Neither periodontal pocketing nor loss of marginal alveolar bone was observed.

Comparative study of oral conditions in schoolchildren of Strasbourg, France, 1974-85

A representative sample of 1650 children randomly selected in the 6-15-yr-old schoolchild population of Strasbourg was examined by well-calibrated examiners. The prevalence of caries was determined with the DMFT, DMFS and dft indices using bitewing radiographs. Plaque, calculus and gingival indices were also determined. The results obtained were compared with the initial study of 1974 performed in Strasbourg using the same epidemiologic methods. Whereas no important variations were observed in caries prevalence of primary teeth, a significant reduction of caries activity was observed in DMFT and DMFS indices in all age groups. There was a reduction of these two indices of respectively 32% and 33% in the 12-yr-old children. The reduction was the most significant on approximal surface lesions. A statistically significant decrease of the calculus and gingival indices was also observed between 1974 and 1984. A less significant decrease was observed for the plaque index.

Streptococcus mutans levels in saliva and distribution of serotypes among 9-year-old Icelandic children

Streptococcus mutans levels in saliva were determined in 9-yr-old children from five towns in Iceland. In four towns the mean counts were greater than 10(5)/ml. Serotype c was predominant but types e and d/g were also found. The proportion of children harbouring serotype d/g alone or in combination with other serotypes was higher than that reported in most other studies.