Dental Caries Status and Trends in 5 Years Old Children in the Republic of Korea

Abstract

This study aimed to examine the current status of dental caries in primary teeth of 5-year-old children in the Republic of Korea using data from the Korea National Children’s Oral Health Survey. Data from 8,344 children (4,216 boys and 4,128 girls) from 215 daycare centers and 201 kindergartens nationwide who participated in the survey were analyzed in this study. The analyses conducted on the 2021–2022 Korea National Children’s Oral Health Survey data showed that the experience rate of dental caries in primary teeth was 66.4%, and the prevalence was 30.2%. The prevalence of dental caries in primary teeth were higher in girls than in boys. In addition, the experience rate level was associated with geography. The rate of severe early childhood caries (S-ECC) was high (46.1%), with one in two children having S-ECC. The experience rate of dental caries in primary teeth is more than 10 percentage points higher than the target of 55.0% in the National Health Promotion Plan (Health Plan 2030). Active interventions are needed to improve children's oral health, such as oral health education for proper oral care and regular dental visits to prevent primary caries.

Key messages

① What is known previously?

In 2018, the experience rate of 5-year-old children in the Republic of Korea with the experience rate of dental caries in primary teeth was 68.5%, and the prevalence of dental caries in primary teeth was 33.9%.

② What new information is presented?

The 2021–2022 Korea National Children’s Oral Health Survey data showed that the experience rate of dental caries in primary teeth was 66.4% and the prevalence was 30.2%, and the rate of severe early childhood caries (S-ECC) was 46.1%. The experience rate and prevalence of dental caries in primary teeth were higher in girls than in boys. In addition, the experience rate and S-ECC were linked to geography.

③ What are implications?

The experience rate of dental caries in primary teeth is more than 10 percentage points higher than the target of 55.0% in the National Health Promotion Plan (Health Plan 2030). Active interventions are needed to improve children's oral health, such as oral health education for proper oral care and regular dental visits to prevent primary caries.

Introduction

Dental caries is characterized by the demineralization of the enamel and dentin of teeth by acids, thereby a significant threat to children’s oral health, and these acids are metabolic byproducts of certain bacteria in the oral cavity [1]. Early childhood caries (ECC) refers to the presence of one or more cavities or filled (treated) tooth surfaces in the primary teeth of children aged 71 months or younger [2]. Severe ECC (S-ECC) is defined as the presence of smooth surface caries in children under 3 years of age and the presence of one or more caries, tooth loss due to caries, or smooth surface filling in the maxillary anterior teeth at 3 to 5 years of age; or the number of caries, tooth loss, and fillings of four or more at 3 years of age, five or more at 4 years of age, and six or more at 5 years of age [3].

The primary teeth not only affect pronunciation, mastication, and aesthetics but also maintain space for permanent teeth and facilitate the proper development of jawbones [4]. Dental caries occurring in the primary teeth indicates a high likelihood of caries occurring in the permanent teeth. The early loss of primary teeth due to caries can lead to malocclusion and pronunciation problems, which can have negative impacts on appearance, self-esteem, and quality of life later in life. The effective management of dental caries during primary dentition plays a crucial role in lifelong oral health. Most oral diseases are closely related to oral health during childhood. Since most dental conditions are preventable, oral health management is crucial for maintaining oral health. To maintain good oral health throughout life, it is essential to establish proper oral hygiene habits from childhood and undergo regular check-ups and monitoring [5].

The Korea National Children’s Oral Health Survey is conducted every 3 years to monitor the oral health of 5-year-olds, representing the level of primary teeth health, and 12-year-olds, representing the level of permanent teeth health. This study aims to examine the status of primary teeth health among 5-year-old children in the Republic of Korea (ROK) and the prevalence of S-ECC using the results of the 2021–2022 Korea National Children’s Oral Health Survey.

Methods

1. Study Subjects

Data from the 2021–2022 Korea National Children’s Oral Health Survey was used to examine the oral health status of 5-year-old children. The target population of the survey was comprised of 8,344 children, consisting of 4,216 boys and 4,128 girls, attending 215 daycare centers and 201 kindergartens nationwide. All children who participated in the survey without any exclusions were included in the analysis. Additionally, to understand the trend in primary teeth health over the past 12 years (2010–2022), data from the Korea National Children’s Oral Health Survey conducted since 2010 were utilized. The number of subjects in the surveys conducted in 2010, 2012, 2015, and 2018 were 3,857 (2,063 boys and 1,794 girls), 2,948 (1,478 boys and 1,470 girls), 1,822 (931 boys and 891 girls), and 6,819 (3,520 boys and 3,299 girls), respectively.

2. Research Methods

The condition of the children’s teeth was verified through oral examinations by dentists trained as oral health examiners visiting each institution. The study was approved by the Institutional Review Board (GWNUIRB-2021-35-1). Written informed consent was obtained from all participants. The experience rate of dental caries in primary teeth was defined as the proportion of individuals who either had decayed teeth or received fillings (treatment) due to decay. The prevalence of dental caries in primary teeth refers to the proportion of individuals with active dental caries in primary teeth. S-ECC was defined as the proportion of individuals who have decayed teeth experienced tooth loss or received fillings (treatment) due to decay in six or more surfaces.

3. Data Analysis

The collected data were analyzed using the IBM SPSS 28.0 for Windows software (IBM Corp.), and statistical significance was set at a significance level of p<0.05. The experience rate of dental caries in primary teeth, the prevalence of dental caries in primary teeth, and S-ECC by the characteristics of the subjects were analyzed using the chi-squared test.

Results

1. Trends in Dental Caries in Primary Teeth among 5-Year-Olds in the ROK

From 2010 to 2022, the experience rate of dental caries in primary showed an increasing trend. When comparing by sex, from 2010 to 2018, boys had a higher rate of dental caries in primary teeth than girls. However, in 2021–2022, girls had a higher rate than boys (Figure 1). In 2021–2022, the experience rate of dental caries in primary teeth was 66.4% overall, which was more than 10% higher than the Health Plan 2030 target of 55.0%. In 2021–2022, the prevalence of dental caries in primary teeth was 30.2%, which was lower than that in 2010. The prevalence of dental caries in primary teeth was higher in boys than girls from 2010 to 2018, By contrast, in 2021–2022, girls had a higher prevalence than boys (Figure 2).

Figure 1. Trends in 5-year-old primary caries experience rate, 2010–2022.

HP=health plan.

Figure 2. Trends in 5-year-old primary caries prevalence, 2010–2022.

2. Status of Oral Health among 5-Year-Olds in 2021–2022

The oral health status of 5-year-old children in 2021–2022 Korea National Children’s Oral Health Survey is presented in Table 1. The experience rate of dental caries in primary teeth did not differ significantly by sex or between children attending daycare centers and kindergartens. However, it prevalence was significantly higher in rural areas (counties) (66.0%) than in urban areas (cities) (71.1%) (p<0.05) as well as in girls (31.9%) than in boys (28.6%) (p<0.05). Differences according to institution and region were not significant. S-ECC was more frequent in rural areas (counties) (50.7%) than in urban areas (cities) (45.7%).

Table 1. Dental caries experience and prevalence .

Variable	Prevalence of dental caries experience	p-value	Prevalence of active dental caries	p-value	Severe early childhood caries	p-value
Total	66.4 (0.9)		30.2 (0.9)		46.1 (0.9)
Sex		0.505		0.023*		0.642
Boys	65.8 (1.2)		28.6 (1.2)		45.7 (1.2)
Girls	66.9 (1.2)		31.9 (1.1)		46.5 (1.3)
Center		0.981		0.226		0.394
Day care centers	66.3 (1.3)		31.6 (1.6)		45.2 (1.3)
Kindergartens	66.4 (1.2)		29.3 (1.1)		46.7 (1.1)
Geography		0.005*		0.058		0.005*
Urban	66.0 (0.9)		30.0 (1.0)		45.7 (0.9)
Rural	71.1 (1.4)		33.2 (1.4)		50.7 (1.5)

Unit: % (standard deviation). *p<0.05.

Discussion

The results of the analysis of the Korea National Children’s Oral Health Survey from 2010 to 2022 revealed an increasing trend in the experience rate of dental caries in primary teeth and a decreasing trend in the prevalence of dental caries in primary teeth. As of 2021–2022, 66.4% of 5-year-old children experienced dental caries in primary teeth, 30.2% had untreated dental caries in primary teeth, and 46.1% had experienced S-ECC (decay affecting six or more tooth surfaces). According to the Korea National Children’s Oral Health Survey report [5], the experience rate of dental caries in primary teeth decreased sharply from 83.3% in 2000 to 77.3% in 2006 and continued to decline until 2010 (61.5%). However, the rate subsequently increased to 68.5% in 2018 and decreased by 2.0% to 66.4% in 2021–2022. The prevalence of dental caries in primary teeth showed a sharp decrease from 63.9% in 2000 to 31.5% in 2006, followed by a steady decline until 2015. However, a slight increase was observed in 2018, followed by a decrease to 30.2% in 2021–2022. Thus, the experience rate of dental caries in primary teeth decreased from 2000 to 2010 and has remained relatively stable in the past decade. The prevalence of dental caries in primary teeth has been decreasing but remains high. Results from oral examinations conducted on 5-year-old children in the United Kingdom showed a decrease in the experience rate of dental caries in primary teeth from 30.8% in 2008 to 23.3% in 2017, followed by a slight increase to 29.3% in 2022, in contrast to the trend observed in the ROK [6].

When comparing the prevalence of dental caries in primary teeth by sex, boys had a higher prevalence than girls from 2010 to 2018. However, in 2021–2022, girls showed a higher prevalence than boys. The trend observed in the 2021–2022 survey contradicts findings from previous international studies that boys had a higher prevalence of dental caries in primary teeth than girls [7,8]. Further research, including the 2024 Korea National Children’s Oral Health Survey, is warranted to determine whether these differences are temporary or influenced by other factors. The experience rate of dental caries in primary teeth and S-ECC was higher in rural areas (counties) compared to urban areas (cities). Yang and Cho [9] found a higher prevalence of dental caries in primary teeth in rural areas (counties) than in urban areas (cities), which is similar to the findings of the present study. These results suggest that the accessibility of dental healthcare services may act as a barrier to oral health.

To prevent dental caries, a disease that poses a significant socioeconomic burden, the 5th National Health Promotion Plan set a target to reduce the experience rate of dental caries in primary teeth to 55.0%. However, as of 2021–2022, the rate was 66.4%, exceeding the target by more than 10%. This suggests that in addition to promoting dental caries in permanent teeth prevention projects, more active efforts are needed to promote oral health projects and insurance coverage for preventive dental care to prevent caries in early childhood. Active interventions and promotion efforts are necessary to improve children’s oral health status, including oral health education for proper oral hygiene practices, regular dental visits for the application of fluoride, and preventive treatment, such as dental sealants.

Funding Statement

Funding Source: None.