Caries Prevalence in Israeli School Children, Aged 6-16 Years in 2026 Leiboviz-Haviv Shirley, Gaon Ofir, Mimoun Nofar, Michal Ben-Shitrit

Introduction

Policies of dental care for children have undergone dramatic changes in Israel during the last decades. Nationwide water fluoridation in Israel started in 2002 and led to a significant reduction in caries among children (Levy et al. 2023). However, a legislative change terminated it in 2014 (Levy et al. 2023; Yavnai et al. 2020), despite the opposition by the Israeli Dental Association, the Israeli Arab Dental Association, and senior university public health experts attacked the decision (Siegel-Itzkovich 2014). Children exposed to water fluoridation in Israel till 2014 had significantly lower rates of caries-related treatment, regardless of access to free dental care (Levy et al. 2023).

In 2010, free dental care for children was included in the National Health Insurance Law, providing free dental care for children under 8 years of age (Natapov et al. 2016; Yavnai et al. 2020). Until then, only School Dental Services, financed by state and provided by local authorities, offered dental care to primary school children in Israel . Most of the dental treatment was paid out of pocket but the high cost did not translate into a better oral health for Israeli children (Natapov et al. 2016). Free dental treatment for children expanded gradually (Yavnai et al. 2020) and from 2018 all children and adolescents up to the age of 18 years are eligible for free dental treatment at the four health insurance companies of Israel.

In the past twelve years children in Israel are entitled to free dental care, but their drinking water is not fluoridated. The present largescale study was designed to assess the oral health needs of Israeli children by measuring their DMFT, a measure approved by the World Health Organization (WHO) Oral Health Survey Methods (World Health Organization 2013). This measure aims to predict oral health needs in a population based on the number of teeth with decay (D in permanent dentition and d in primary dentition), missing teeth due to extractions (M/m), and teeth with restorations (F/f). DMFT (Decayed, Missing, Filled Teeth) in permanent dentition, or dmft in primary dentition, are universally accepted and are the most widely used indexes to assess caries experience (Broadbent and Thomson 2005).

During the last decades Israeli children have shown high DMFT/ dmft scores (Natapov et al. 2016), as demonstrated by several epidemiological surveys conducted since 1990, when a national survey among primary school children aged 5 (N=767) and 12 years (N=762) was performed. The survey reported a dmft of 2.7 and that 41% of children were caries free (Zadik et al. 1992). Several surveys followed: In 2002, the DMFT of 12-year-old children was 1.66 and 46% were caries free (Zusman et al. 2005). In 2016, a survey on 1,210 6–7-year-old children found a dmf of 2.56 and that 38.3% were caries free. This was the first time more teeth were found that were treated with fillings (f) than left untreated (d) (Natapov et al. 2016). In another survey performed in 2016 on 702 18-year-old Israelis, the DMFT was 1.95 and 46.7% were caries free (Yavnai et al. 2020).

The small scale of dmf/DMF data on Israeli children and adolescents during the last decades, as well as the small number of participants per age group, impair policymakers’ ability to assess the scale of the population’s needs and may undermine the design of efficient large-scale caries-prevention programs.

The present epidemiologic study is the largest of its kind performed in Israel to date. Over 7,000 school children aged 6-16 years from the city of Ashkelon were examined and their dmf/DMF data inform on the dental status of Israeli children.

Materials & Methods

A total of 7,011 healthy children from 18 schools in the city of Ashkelon, grades 1-9 (ages 6-16 years), were included in the study. The DMF/dmf scoring was performed during the annual dental examination of school children aimed to assess their dental needs. The annual examination is approved by the municipal authorities. The parents of the children signed an approval statement to examine the dental status of the children at school. The children were examined by four second year residents specializing in pediatric dentistry, with vast experience in dental examinations, according to the WHO Oral Health Survey Method (World Health Organization 2013). Each child was examined sitting, facing a natural light source, using only a dental mirror. One resident examined the child and a second resident, or an experienced dental assistant filled the dmf/DMF chart. The residents participated in a calibration exercise conducted by an experienced pediatric dentist (HLS) until a Cohen’s Kappa (McHugh 2012) of 0.85 or higher was achieved. The socioeconomic status of the examined children was based on the location of the schools and was received from the Ashkelon municipality.

Statistical Analysis

The data was transferred to a computer, and group comparisons were tested using non-parametric tests. Differences in caries prevalence were tested using chi-square tests, differences in DMFT between each two groups were tested using the Mann-Whitney test, and differences among three or more groups were tested using the Kruskal-Wallis’s test. Results

Sample Description

A total of 7,011 students who underwent dental examinations in 18 schools in the city of Ashkelon, in grades 1 to 9 (aged 6-16 years), were included in the study. The sample comprised 3,683 boys (52.5%) and 3,328 girls (47.5%). 3,268 students (46.6%) were in primary school (grades 1 to 6) and 3,743 students (53.4%) were in middle school (grades 7 to 9). The distribution of students by grade is presented in Table 1.

Table 1: Distribution of students by grade.

Caries Prevalence and Mean DMFT

Caries prevalence in the total sample was 47.4%, with 52.6% of students being caries-free. The mean DMFT was 1.76 (SD=2.61), and the range was 0 to 24.The distribution of DMFT scores in the sample was asymmetric and right-skewed, with a marked concentration of zero scores (that belong to the caries-free participants). The median is therefore reported alongside the mean.

Caries prevalence and mean DMFT by grade and age groups are presented in Table 2. An increase in the lower grades followed by a decline in higher grades was observed, with the peak of caries in grades 2 and 3 (prevalence of 58.8% and 63.4%, respectively) and a gradual decline to about 40% in the middle-school grades.

These differences among grades were significant, both in caries prevalence (χ²(8) = 182.63, p < .001), and in mean DMFT, (H(8) = 302.65, p < .001). Subsequent pairwise comparisons with Bonferroni correction (Dunn’s test for DMFT scores and comparison of proportions for prevalence) indicated the same pattern for both measures. Grades 2, 3, and 4, in which the peak of caries was found, had a higher DMFT than most other grades (p ≤ .002 for all significant comparisons) and did not differ from one another. The middle-school grades (7, 8, and 9) showed the lowest levels of DMFT and did not differ from one another. Grade 1 differed from the middle-school grades (p≤.001), whereas grade 6 did not differ from them.

Table 2: Caries prevalence and mean DMFT by grade (per age group).

DMFT by sex

Examining the difference between the sexes per grade (Table 3) revealed a higher DMFT score among boys in grade 4 (ages 9-10) (z = -2.88, p = .004), and among girls in grade 8 (ages 13-14) (z = -2.02, p = .044). No other inter- sex differences were found in the remaining grades and in the total sample.

Table 3: Mean DMFT by sex.

Caries prevalence and socio-economic status

The socioeconomic status in Ashkelon was between 5-7. In the overall analysis, the socioeconomic levels differed in caries prevalence (χ²(3) = 22.03, p < .001), and in DMFT score (H(3) = 46.55, p < .001), with higher DMFT scores found in the lower socioeconomic groups. Caries prevalence and mean DMFT by socioeconomic status are presented in Table 4. Pairwise comparisons with Bonferroni correction showed that the integration group had lower DMFT scores than group 5 (p < .001) and group 5-6 (p = .008). Group 5 had higher caries prevalence (at a corrected level of p < .05) than group 6-7 and the integration group.

Table 4: Caries prevalence and mean DMFT by socioeconomic status.

Caries components (dmf/DMF) by tooth groups

The caries components for each tooth group, primary (dmf) and permanent teeth (DMF) are presented in Table 5 (primary dentition) and Table 6 (permanent dentition).

Table 5: Caries Components by Primary Tooth Group.

Table 6: Caries Components by Permanent Tooth Group.

Caries components by age group

D, M, and F components were examined per age group within each dentition. In the permanent dentition, the mean D component rose from 0.09 at ages 6-7 to 0.67 at ages 14-15, and the mean F component rose from 0.03 to 0.63 over the same range; the M component was 0.02 or lower in every age group. In the primary dentition, the mean d component was highest at ages 8-9 (1.05) and declined to 0.01 at ages 14-15, the mean f component was highest at ages 7-8 (1.34) and declined to 0.01, and the m component was 0.23 or lower in every age group. The components by age group are shown in Figure 1 (permanent dentition) and Figure 2 (primary dentition).

Figure 1: Mean Number of Decayed, Missing, and Filled permanent teeth by age group (N = 7,011). Note: Bars show the mean number of decayed (D), missing (M), and filled (F) permanent teeth per child in each age group.

Figure 2: Mean Number of decayed, missing, and filled primary teeth by age group (N = 7,011). Note: Bars show the mean number of decayed (d), missing (m), and filled (f) primary teeth per child in each age group.

Dental needs by age group and dentition

Mean DMFT/dmft scores were computed separately for the permanent and primary dentitions within each age group (Figure 3). In the permanent dentition, caries prevalence rose with age, from 5.7% at ages 6-7 to 39.5% at ages 14-15, and mean DMF rose from 0.12 to 1.32 over the same range. In the primary dentition, caries prevalence was highest at ages 7-9 (56.3% for 7-8 and 60.5% for 8-9) and declined to 1.5% at ages 14-15. Mean DMF peaked to 2.5-2.6 at ages 7-9 and declined to 0.02 over the same range.

The treated component was higher than the untreated component in all age groups except the youngest (6-7 years), where the treated component was similar to the untreated component. In the permanent dentition, the decayed component was higher than the treated component, except in ages of 9-11 years, where the treated component was higher than the decayed component.

Overall caries prevalence (any tooth, either dentition) by age group is shown in Figure 3.

Figure 3: Caries prevalence by age group and dentition (N = 7,011). Note: Bars show the percentage of children with any caries experience (DMF > 0) in the permanent and primary dentitions, presented separately for each dentition. The two dentitions are shown separately because a child in the mixed-dentition years may have caries in both, and the two percentages therefore cannot be combined into a single value.

We compared the caries prevalence of 6-7 years old children in the current study to that found in a study on 6-year-old children in 2016, who had access to fluoridated water all their life (Natapov et al. 2016). All children had the same socio-economic status level 5-7. As shown in Table 7, the two cohorts did not differ in their caries prevalence.

Table 7: Carries prevalence in 2016 versus 2026.

Carries prevalence in 1^st class students (6-7 years) of socio-economic status level 5-7 who had access to fluoridated water (2016) vs. the prevalence in children from the same age and socio-economic status ten years later (2026), when Israeli children have no access to fluoridated water.