Abstract
Objectives
We aimed to determine the prevalence of dental caries and its associated factors among primary school children in Tunisia.
Methods
A cross-sectional study was conducted among children enrolled in primary schools in Sousse, Tunisia, in April 2022. A systematic random sampling technique was used. A structured questionnaire and medical records were used to collect data. A multivariate analysis was performed using binary logistic regression to identify factors independently associated with dental caries.
Results
In total, 376 children were included. The prevalence of dental caries was 43.9%. Based on a bivariate analysis, many factors were associated with dental caries, such as children from public schools (p < 0.001), lack of tooth brushing (p < 0.001), tooth brushing only 1 time per day (p < 0.001), unhealthy eating habits (p ≤ 0.05), and overweight body mass index (p = 0.016). In multivariate analysis, risk factors for dental caries were age and eating after brushing in the evening, whereas protective factors included frequent tooth brushing and regular toothbrush replacement.
Conclusions
We recommend organizing awareness days in schools, implementing programs on preventive measures against dental caries, and expanding screening campaigns.
Introduction
Oral diseases are a major burden of disease in many countries. These diseases affect 3.5 billion people worldwide, and dental caries is one of the most prevalent conditions. 1 The World Health Organization (WHO) has considered dental caries as the fourth global public health scourge, after cancer, cardiovascular diseases, and acquired immunodeficiency syndrome. 2
The WHO has described the carious lesion as a localized pathological process of external origin, appearing after the eruption of the tooth. 3
Dental caries is a condition that affects not only adults but also children. Globally, an estimated 2 billion people have permanent tooth decay, and 520 million children experienced baby tooth decay in 2019. 4 Moreover, a study performed by the Nutrident team found that 60% of school children worldwide had dental caries. 5 Another study conducted by the National Center for Health Statistics in the United States showed that the prevalence of dental caries among school children aged 6–11 years was 45.2% in 2018. 6 Furthermore, the WHO regional office in Europe revealed that in 2015, 20%–90% of all 6-year-old children had dental caries. 6 These figures were more alarming in developing countries. In particular, the prevalence of dental caries among school children in some African countries was high, with 67.7% in Mali in 2013, 7 49% in Ivory Coast in 2018, 8 and 79% in Mauritania in 2016. 9 Similarly, in the countries of the Greater Maghreb, a national survey on the oral health status of Algerian students, conducted in 2013, revealed a prevalence of 74% for all children aged 6, 12, and 15 years. 3 Furthermore, in Tunisia, where a survey was conducted in 2016 among school children in Jelma, the prevalence of dental caries was 83.5%. 10 Another survey conducted in Tunisia in 2012 showed that 29% of school children (aged 7–12 years) had tooth decay. 11
Furthermore, research has shown that dental caries is caused by the interaction of several factors, such as eating habits and oral hygiene. Nutritional deficiencies and sugar overconsumption are the main etiologies. 12 Good oral hygiene is essential to ensure a healthy dentition. Thus, regular cleaning of the teeth enables the removal of dental plaque containing bacteria and preserves healthy teeth as long as possible by protecting them from the carious process and periodontal diseases. 13 Therefore, an analysis of these factors is an essential step to ensure the development of best prevention strategies against this global scourge. 14
However, studies on dental caries among school children in Tunisia are currently limited. Thus, the purpose of this study was to determine the prevalence of dental caries and its associated factors among primary school children in Sousse, Tunisia.
Methods
Study design and setting
A cross-sectional study was conducted among primary school children in Sousse, Tunisia, during the academic year 2021–2022.
Study participants
Children from three primary schools— “El Amarat North, Khzema East, and Pythagore”—who were aged 6–13 years, were in first or third grade, and lived in Sousse were enrolled in our study.
The inclusion criteria were as follows: (a) children enrolled in the abovementioned schools who were present on the day of the survey and agreed to participate in our study; (b) those in the first or third year of primary school who were present at the systematic school medical check-up; and (c) those whose parents accepted their participation in our study.
The exclusion criterion included children who refused to answer the questionnaire.
Sample size and sampling
The sample size was calculated using the single population proportion formula, assuming a 95% confidence interval (CI), 5% margin of error, and dental caries prevalence of 29.58%, resulting in a final sample size of 320. 11
A systematic random sampling technique was employed to select the study participants. We randomly selected Sousse delegation 1, which included 10 schools, of which 4 were private. To obtain a representative sample, three schools were selected randomly; the total number was 1247. Twenty basic first and third classes were included for each institution. Our total sample size was 376 children.
Data collection
For data collection, we used a structured questionnaire and the medical records of participants. The questionnaire covered the following variables:
Sociodemographic data: age, sex, origin (urban/rural), and type of school (public/private). Oral hygiene practices: frequency of tooth brushing per day, brushing time, products used for brushing, and frequency of changing the toothbrush. Dental consultation behaviors: history of visiting the dentist, reason for consultation, and fear of the dentist. Dietary habits: frequency of consumption of milk, bread, eggs, sweet foods (e.g. cakes and jam), and fruit juice as well as eating at night after brushing teeth. We collected detailed data on the frequency of consumption of various sweet and cariogenic foods because they differ in form, texture, sugar content, and how often they are consumed, factors that may influence their potential to cause dental caries.
The study was conducted in April 2022 under the supervision of the school nurses responsible for each school, after being authorized by the school doctor and the head of the district delegation of the region. The survey was conducted at the beginning of the sessions after the teacher’s authorization. After explaining the objective of our study and the content of the questionnaire, emphasizing on confidentiality and anonymity, the children completed the questionnaire. Following appropriate infection control measures, oral examinations were performed by trained dentists under standardized conditions, with participants seated on a chair in a well-lit environment, using sterile dental mirrors and explorers. The Decayed, Missing, Filled Teeth (DMFT) index was used as the diagnostic criterion for caries assessment.
Data analysis
Statistical analysis was performed using SPSS statistical package (version 20.0, SPSS Inc, Chicago, IL, USA). Quantitative variables were presented as means and standard deviation and compared using the Student t-test. Qualitative variables were presented by numbers and percentages and compared using the chi-squared test or Fisher’s exact test.
A multivariate analysis was performed using binary logistic regression to identify factors independently associated with dental caries.
The significance level was set at p value <0.05.
Ethical considerations
The study was conducted in accordance with the principles of the Declaration of Helsinki. Ethical approval was obtained from the regional education delegate of Sousse and the director of each school. A consent was obtained from the children’s parents before the interview. Participation in research was voluntary, with clear and complete information provided to children. The anonymity and confidentiality of the data were maintained. All personal information of the participants was de-identified to ensure anonymity and prevent any possible identification.
Results
Characteristics of the study population
A total of 376 children were enrolled in the study. Among them, 197 were males (52.4%). The mean participant age was 7.4 ± 1.2 years. The participants’ ages ranged from 5 to 12 years.
More than half of the study participants did not visit the dentist (n = 204; 54.2%). Almost half of the study participants consulted the dentist only when they had a problem (n = 195; 51.9%). The majority of students admitted that they were not afraid of the dentist (n = 220; 58.5%).
Half of the children (49.7%) consumed milk 1–2 times a day. All participants consumed bread. The frequency of egg consumption was daily for 221 respondents (58.8%). Moreover, 240 children (68.8%) consumed fruit juice 1–2 times a day. Most of the children (55.8%) consumed sweet foods.
The majority of the children (n = 287; 76%) brushed their teeth. Among them, 129 (44.9%) cleaned their teeth only once a day, 112 (39%) cleaned their teeth 2 times a day, and 46 (16%) cleaned their teeth 3 times a day. The majority of the children (n = 276; 96.2%) used toothbrushes with toothpaste for brushing. Less than one-third of the children (n = 84; 29.3%) responded that they ate at night after brushing their teeth. The majority of the children (n = 224; 59.7%) changed their toothbrushes. One-third of the children (n = 74; 33.2%) changed their toothbrushes every 6 months.
Factors associated with dental caries
Univariate analysis
Among the 320 study participants, 165 had decayed teeth (43.9%). The proportion of missing teeth was 0.5%. Only 8.2% of our population had treated teeth. Girls had a higher prevalence of dental caries than boys (44.1% vs. 43.7%; p = 0.925). The prevalence rates of dental caries were 52.6% and 21.2% among children from state schools and private schools, respectively. This difference was statistically significant (p < 0.001). Children who did not brush their teeth had the highest prevalence of dental caries (98.9% vs. 26.8%; p < 0.001). Thus, the prevalence of dental caries was significantly higher among students who cleaned their teeth only once a day (p < 0.001). In addition, the prevalence of tooth decay was higher among students who cleaned their teeth before breakfast than in those who cleaned their teeth after each meal, namely, breakfast, lunch, and dinner (29.7% vs. 8%, 10.2%, and 21.5%). This difference was statistically significant (p < 0.001). The prevalence of tooth decay was also significantly greater among students who ate at night after brushing their teeth (81% vs. 4.4%; p < 0.001) and who did not change their toothbrushes (87.4%; p < 0.001). A significant association was also found with sweet food consumption, snacking, and being overweight (p < 0.005; p < 0.001; p = 0.016, respectively) (Table 1).
Factors associated with dental caries in primary school children in Sousse, Tunisia, in 2022 (univariate analysis).
Multivariate analysis
In the multivariate analysis, independent risk factors for dental caries were age (adjusted odds ratio (aOR) = 1.757; 95% CI: 1.126–2.740; p = 0.013) and eating in the evening after brushing teeth (aOR = 56.680; 95% CI: 19.938–161.135; p ≤ 10−3). Protective factors included tooth brushing frequency, with brushing twice a day (aOR = 0.254; 95% CI: 0.089–0.726; p = 0.011) and brushing more than twice a day (aOR = 0.079; 95% CI: 0.011–0.587; p = 0.013) significantly reducing the risk compared with brushing once daily. Additionally, regular toothbrush replacement was associated with a lower risk of dental caries (aOR = 0.114; 95% CI: 0.040–0.329; p ≤ 10−3) (Table 2).
Factors associated with dental caries among primary school children in Sousse, Tunisia, in 2022 (multivariate analysis).
aOR: adjusted odds ratio; CI: confidence interval.
Discussion
Dental caries is a common health problem among primary school children worldwide. Without timely treatment, it can be the first cause of dental pain and tooth loss. 15 Moreover, it affects the chewing function, speech, and quality of life of the child. 16 The objective of the WHO and the International Federation of Dental Medicine is to keep more than half of the children free of caries worldwide. 17 The prevalence rate observed in our study (43.9%) seemed close to this objective. 17 This prevalence was comparable to those reported in two studies conducted in Ethiopia and China (40.98% and 41.17%, respectively).18,19 However, it was lower than that reported in a study conducted in Spain (81.87%). 20 The difference could be due to differences in the number of samples, knowledge, and attitude on oral hygiene, as our study was performed among urban school children.
Moreover, our research showed that 8.2% of our population had treated teeth. A tooth is considered treated or filled when it has undergone one or more permanent restorations. This percentage was close to the result found in China in 2017, which was estimated to be 9.29% among 7-year-old students. 19 Unlike Australia, 90% of children underwent restoration of their decayed teeth. 19 However, the rate of restoration of decayed teeth in our population was lower than that found in some developed countries, which emphasizes the importance of oral health education.
Our study found that the risk of dental caries increased with aging; moreover, it increased among children who ate after brushing in the evening. In contrast, the risk decreased with frequent tooth brushing and regular toothbrush replacement in multivariate analysis. The risk factors for caries include low socioeconomic level, poor oral hygiene, non-use of toothpaste, and eating sweet foods. 20
A cross-sectional study among 6–12-year-old children in marginalized areas of Valencia (Spain) found no significant association between DMFT and sex, age, diet, dental visits, or plaque index but showed significant links with ethnicity and brushing frequency. Plaque index was also significantly associated with diet and dental visits. 21
Some studies have shown that children who study in state schools have a higher prevalence of dental caries due to the difference in socioeconomic level. 22 Moreover, several studies showed this difference, including a study conducted in China and another conducted in the Middle East.22,23
According to our results, 76% of the children reported that they brushed their teeth. There was a statistically significant association between non-brushing of teeth and tooth decay (p = 0.001), frequency of brushing teeth (p < 0.001), and brushing time (p < 0.001). Obviously, adopting negligent oral hygiene habits is a major factor that favors the appearance of dental caries. In this context, approximately 10 studies found similar results. 24 Consequently, recent recommendations showed that teeth cleaning should be performed after each meal and in the evening before bedtime to avoid the formation of dental plaque, which is formed within 24 h. 13
In our study, 96.2% of the students who cleaned their teeth used toothpaste. There was a significant relationship between the non-use of toothpaste and tooth decay. Thus, our results were consistent with those found in the literature; for example, a survey conducted in Ethiopia in 2020 showed a statistically significant association between the non-use of toothpaste and tooth decay. 25 In contrast, another survey published in Nigeria in 2018 showed that the relationship between these two variables is not significant. 26 Moreover, clinical studies have demonstrated the essential role of fluoride toothpastes in the prevention of dental caries. These toothpastes reinforce the action of brushing the teeth by eliminating food debris and dental plaque from the surface of the tooth and interstices. 27
The results of our study showed that the occurrence of dental caries was significantly associated with eating in the evening after brushing the teeth.
Similarly, another study conducted in Saudi Arabia in 2018 concluded the importance of the association between sleeping with a bottle in the mouth and dental caries. 28 Indeed, this association is scientifically explained by the decrease in salivary secretions and consequently the reduction of swallowing reflex in children in the evening during sleep, which allows carbohydrates to remain on the tooth surface and favors bacterial growth in this area. 29
In our study, a strong association was found between the consumption of sweet foods and the appearance of dental caries. Thus, several studies have been conducted on the effect of sugar, particularly sweetened drinks, on dental health. Some studies, such as that conducted in Quebec in 2021, 30 that conducted in Libya in 2019, 31 those conducted in northeastern Ethiopia in 2019 and in eastern Ethiopia in 2020,25,32 showed a strong association between sweet foods and the prevalence of caries, which is explained by the fermentation and transformation of carbohydrates in the mouth into acids under the action of the bacteria present in the dental plaque. 33
According to studies conducted in China in 2017, 19 in India in 2019, and in Qatar in 2013,23,34 the prevalence of dental caries increased in obese individuals. In the majority of these individuals, snacking causes an increased difficulty in maintaining good oral hygiene; however, bringing foods rich in refined sugars allows the growth of intra-oral bacteria and thus causes caries. This is consistent with our study, which found a significant association between caries and sweet food consumption, snacking, and being overweight. 35
Our study has some limitations. Dental caries was identified only with data collected from school medical records, which may not contain detailed information. Moreover, other grades were not included due to the lack of a systematic medical examination. Furthermore, we did not analyze dental caries separately for primary and permanent teeth or perform subgroup analyses by school grade. Future studies with larger populations are recommended to explore these differences.
Conclusion
This study revealed a high prevalence of dental caries (43.9%) among school children. Several factors were significantly associated with the presence of caries, including enrollment in public schools, overweight body mass index, poor oral hygiene practices (such as infrequent or absent tooth brushing, eating after brushing at night, and not changing toothbrushes), and unhealthy dietary habits. In multivariate analysis, the risk of dental caries increased with aging; moreover, it increased among children who ate after brushing teeth in the evening. In contrast, the risk decreased with frequent tooth brushing and regular toothbrush replacement.
Dental caries is a global public health scourge. In fact, the number of individuals affected with dental caries, especially among school-age children, is alarming, as observed in Tunisia. We recommend organizing awareness and information days in schools, implementing educational programs on preventive measures against dental caries, and expanding screening campaigns to improve early detection of this disease.
Footnotes
Acknowledgments
Not applicable.
Author contributions
Conceptualization: Hela Ghali, Syrine Souai, Sana Bhiri, Fatima Ezzahra Khouya; Methodology: Hela Ghali, Amani Maatouk, Henda Selmi, Khissal Youssef, Salwa Khefacha; Project administration:, Hela Ghali, Mohamed Ben Rejeb, Houyem Said Latiri; Supervision: Salwa Khefacha, Mohamed Ben Rejeb, Houyem Said Latiri, Asma Ben Cheikh; Visualization: Houyem Said Latiri, Asma Ben Cheikh; Writing–original draft: Hela Ghali, Syrine Souai, Sana Bhiri, Amani Maatouk, Fatima Ezzahra Khouya, Henda Selmi, Khissal Youssef; Writing–review & editing: Salwa Khefacha, Mohamed Ben Rejeb, Houyem Said Latiri, Asma Ben Cheikh.
Data availability statement
The datasets used and/or analyzed for this study are available upon reasonable request from the corresponding author.
Declaration of conflicting interests
The authors declare no competing interest.
Funding
This study received no funding.
