Socio-behavioral and clinical determinants of high caries experience among 12-year-old Thai schoolchildren: a cross-sectional study

1. Introduction

Dental caries remains one of the most prevalent chronic diseases affecting children and adolescents worldwide, imposing a substantial burden on health, quality of life, and healthcare systems [1, 2, 3]. As a multifactorial disease influenced by biological, behavioral, and socio-environmental factors, effective prevention requires comprehensive and holistic approaches [4, 5]. In Thailand, dental caries remains a major public health concern among school-aged children, as evidenced by both national oral health surveys and recent regional studies [6, 7]. The 2023 national oral health survey reported a prevalence of 49.7% among 12-year-old children [7]. Despite ongoing preventive programs [8], a substantial proportion of children continue to experience dental caries [9], while untreated decay and caries-related risk behaviors persist [7]. The burden falls disproportionately on children from socioeconomically disadvantaged backgrounds. Key determinants include socioeconomic status, oral health behaviors, dietary practices, access to dental care, and clinical factors such as enamel defects [10, 11, 12, 13, 14, 15].

School-aged children are in a transitional phase toward adolescence, during which they begin to develop greater autonomy in health-related behaviors, including oral hygiene practices and dietary behaviors [16, 17]. The age of 12 years has been identified by the World Health Organization (WHO) as a key index age for monitoring oral health, as most permanent teeth have erupted and behaviors become more established, allowing cumulative caries experience to be more reliably assessed [18]. This represents a critical window for understanding the influence of behavioral and environmental determinants on dental caries [19, 20].

Caries experience in this age group, commonly assessed using the Decayed, Missing, and Filled Permanent Teeth (DMFT) index, a WHO-recommended epidemiological tool [18], reflects the cumulative history of dental caries in an individual or population. Beyond reflecting current tooth decay alone, the DMFT index captures evidence of both past and present disease through decayed, missing, and filled teeth, thereby providing a more comprehensive assessment of lifetime caries burden and offering broader insight into an individual’s oral health status, including patterns of dental service utilization and access to dental care [21].

Children with high caries experience may represent a particularly high-risk group that warrants further investigation. A better understanding of the factors associated with high caries experience is essential for identifying high-risk groups and developing targeted prevention strategies. Therefore, this study aimed to identify the socio-behavioral and oral health-related clinical factors associated with high caries experience among 12-year-old schoolchildren, with the goal of elucidating the underlying determinants of these impacts and informing interventions to improve the oral health of Thai schoolchildren. We hypothesized that unfavorable socio-behavioral factors and poor oral health conditions would be significantly associated with high caries experience in this population.

2. Materials and methods

3. Results

A total of 423 children were initially assessed for eligibility. After excluding 2 children with ongoing orthodontic treatment, and 21 children with incomplete questionnaires (caregiver questionnaires or child interviews), 400 children were included in the final analysis. The overall non-response rate was 5.0%.

4. Discussion

This study identified several socio-behavioral and clinical-related factors associated with high caries experience among Thai 12-year-old schoolchildren. A substantial burden of dental caries was observed in this population, with more than two-thirds of children experiencing caries and nearly half classified as having high caries experience. The mean DMFT score in this study (2.60) was considerably higher than that reported in the Thai National Oral Health Survey [7] (DMFT = 1.2), as well as those reported in other countries [12, 26, 27, 28, 29]. This discrepancy may reflect differences in study settings, population characteristics, and potential clustering of high-risk individuals in the selected schools. Notably, our study found that MT and FT were low, indicating that the DMFT score was predominantly driven by DT. This pattern may reflect poor oral health status and suggest a substantial unmet need for dental treatment [21], despite the study being conducted in a non-rural setting. Furthermore, the high SiC index observed in this study suggested that dental caries is disproportionately concentrated among a subgroup of children with the highest disease burden. This finding indicates a clear polarization of dental caries and highlights substantial inequalities in oral health within the study population [20, 30, 31].

Socioeconomic status, particularly low caregiver education level and low family income, remained significantly associated with high caries experience, with children from disadvantaged families being more likely to experience higher levels of caries [26, 32, 33, 34, 35, 36, 37]. This may partly reflect the continued influence of family and caregiver-related factors during the transition to adolescence, when children still largely depend on their families and caregivers. Consistent with this, poor caregiver oral health has been associated with increased caries prevalence among children and adolescents [38]. Family income reflects access to essential resources, such as dental care services, fluoride products, and healthy dietary options, all of which are critical for maintaining oral health [39]. In addition, caregiver education may be associated with oral health knowledge [40] and the capacity to promote appropriate oral health behaviors in children. These indicators remain strong determinants of oral health inequalities and are commonly used as proxies for assessing caries risk [10, 37]. However, no significant associations were found between high caries experience and caregiver-related or child-related characteristics, including caregiver age, sex, birth order, and BMI. The lack of association with BMI is consistent with a previous study [41]. Although other studies reported an association between BMI and dental caries [42], the relationship remains inconclusive, possibly reflecting the multifactorial nature of dental caries [43, 44], which is shaped by complex behavioral, dietary, and socioeconomic factors not fully captured by BMI alone [45].

It was noted that enamel defects were strongly associated with high caries experience. This finding is expected, as enamel defects are well-established risk factors for dental caries and are commonly included in caries risk assessment models [10]. Teeth with enamel defects are inherently more susceptible to caries due to their compromised structure, which increases vulnerability to demineralization and disease progression [14]. Consequently, enamel defects were associated with higher DMFT scores, consistent with findings from previous studies [46, 47]. These findings highlight the importance of early identification and management of enamel defects in children. Children with enamel defects should receive more intensive preventive care, including active dental monitoring and preventive strategies such as the application of remineralizing agents (e.g., fluoride varnish and casein phosphopeptide–amorphous calcium phosphate (CPP-ACP)), dental sealants, and intensive oral hygiene instruction [48, 49, 50]. In addition, our study found an association between oral hygiene status and caries experience. Dental biofilm (plaque) is widely used as an indicator in oral health surveys [7, 18] and caries risk assessment tools [10, 51]. Previous studies have also reported that dental biofilm is associated with increased caries prevalence [12, 28]. This finding supports the well-established role of dental biofilm as a primary etiological factor in dental caries, as inadequate dental biofilm control promotes the proliferation of cariogenic bacteria and sustained acid production, leading to demineralization of the tooth structure [52].

Unhealthy dietary and cariogenic consumption behaviors were observed among children with high caries experience, consistent with previous studies [15, 19, 44]. Frequent consumption of cariogenic foods and beverages was common in this age group, with many children reporting daily intake despite existing policies promoting healthy snack consumption [8]. This may reflect the current social and environmental context, where easy access to convenience stores and the continued availability of cariogenic foods contribute to frequent sugar exposure. These findings suggest the need for strengthened environmental and policy-level interventions, particularly within schools, to limit access to cariogenic foods and support healthier dietary choices. Public health policies, such as the WHO recommendation on sugar-sweetened beverage taxation and sugar reduction strategies [53], may help reduce sugar consumption and support caries prevention.

Frequency of toothbrushing may play an important role in caries experience [12, 15, 19]. Children who did not brush their teeth daily had higher odds of high caries experience. Interestingly, a non-significant reverse pattern was observed, with children who brushed once daily appearing to have lower odds of high caries experience compared with those who brushed at least twice daily. This finding should be interpreted with caution, possibly due to reverse causation. Notably, more than half of the children were unaware of their toothbrushing duration, which may reflect a gap in oral health knowledge. However, no significant associations were observed between toothbrushing duration, dental floss use, and high caries experience. Toothbrushing duration alone may not adequately reflect effective plaque control, which also depends on brushing technique, frequency, and supervision [54]. Overall, toothbrushing at least twice daily for at least 2 minutes remains a standard recommendation [55, 56]. In addition, the low prevalence of regular dental floss use may have limited the ability to detect a significant association, despite previous studies reporting an association between floss use and lower caries prevalence [13].

Fluoride toothpaste use was highly prevalent in this population (84.5%). However, no significant association was observed between fluoride toothpaste use and high caries experience, possibly due to the limited variability in its use between groups. In Thailand, most commercially available toothpastes contain fluoride, and their use is widely promoted through national oral health policies [8]. Similarly, no association was observed between dental check-ups and high caries experience, despite 67.0% of participants reporting having had a dental check-up within the past 6 months. Nevertheless, more than two-thirds of the children still experienced dental caries. This may reflect limitations of self-reported data, including recall bias and potential misinterpretation, as well as the influence of routine school-based dental examinations, which may not represent active care-seeking behavior or timely treatment.

It was noted that the internet played an important role as a source of oral health information among children in this age group, with 44.3% of children reporting the internet as their primary source of oral health information, followed by teachers. These findings suggest that digital media and school-based education may play an important role in promoting oral health knowledge and positive oral health behaviors among schoolchildren [57, 58, 59].

The findings of this study have important public health implications. A substantial proportion of children experienced dental caries, while the proportion of filled teeth remained relatively low, suggesting a considerable unmet need for dental treatment in this population. Targeted preventive strategies should focus not only on children with unhealthy oral health behaviors, but also on children from socioeconomically disadvantaged families and those with enamel defects. School-based oral health promotion programs and digital media-based oral health interventions may help reduce the burden of dental caries. In addition, strategies to promote healthier dietary habits and encourage routine oral health visits should be considered.

This study has several limitations. First, the cross-sectional design precludes causal inference. Second, the use of self-reported data from structured questionnaires may be susceptible to recall and reporting bias. Third, the study was conducted in public schools in Pathum Thani Province, which may limit the generalizability of the findings to rural populations or private school settings. Fourth, although a single examiner was used throughout the study to minimize inter-examiner variability, the use of only one examiner may raise concerns regarding objectivity. Additionally, the binary classification of caries experience (high vs. non-high) did not distinguish children with no caries experience (DMFT = 0) as a separate category, which may have limited the identification of factors associated with being free of caries experience. Future studies involving more diverse populations and settings are recommended to improve generalizability. Longitudinal studies are also needed to further investigate causal relationships, evaluate targeted interventions, and explore additional behavioral, environmental, and psychosocial determinants of dental caries.

5. Conclusions

High caries experience among 12-year-old Thai schoolchildren was associated with socioeconomic, behavioral, and oral health-related clinical factors, including low caregiver education (middle school or lower), low family income (≤10,000 THB), enamel defects in permanent molars, fair-to-poor oral hygiene, infrequent toothbrushing, and frequent cariogenic food and beverage consumption. These findings provide insights for developing oral health promotion policies and preventive strategies in this population.

Abbreviations

WHO, World Health Organization; DMFT, Decayed, Missing, and Filled Permanent Teeth; DT, Decayed Teeth; MT, Missing Teeth; FT, Filled Teeth; SiC, Significant Caries Index; THB, Thai Baht; AOR, Adjusted Odds Ratio; CI, Confidence Interval; STROBE, Strengthening the Reporting of Observational Studies in Epidemiology; EPV, Events-per-variable; IOC, Item-Objective Congruence; BMI, Body Mass Index; DDE, Developmental Defects of Enamel; CPP-ACP, casein phosphopeptide–amorphous calcium phosphate; SD, Standard Deviation; IQR, Interquartile Range.

Availability of data and materials

The data presented in this study are available on reasonable request from the corresponding author.

Author contributions

KK—designed the study, collected and analyzed the data, and drafted the manuscript. NP—analyzed the data and revised the manuscript. Both authors read and approved the final manuscript.

Ethics approval and consent to participate

Ethical approval was obtained from the Human Research Ethics Committee, Faculty of Science, Thammasat University, Thailand (HREC-TU COA No. 027/2567). Written informed consent was obtained from legal guardians or primary caregivers, and written assent was obtained from participating children prior to data collection. Participants received information regarding the study objectives, procedures, potential risks and benefits, and their right to withdraw at any time without consequences. All procedures were conducted in accordance with the Declaration of Helsinki.

Acknowledgment

The authors would like to thank Pinpinut Wanichsaithong for valuable consultation regarding the data collection.

Funding

This research was funded by Thammasat University, Thailand (Grant No. TUFT 60/2567).

Conflict of interest

The authors declare no conflict of interest.