Disparities in Dental Caries among Students in Senegalese Koranic School: Epidemiological Study in Daara of Koki

Background: School is a space where children are exposed to the social and psychosocial environment that can affect their health. In Senegal, the prevalence of dental caries is high in classic schools according to fragmented data, and unknown in the koranic school (Daaras). Objective: The objective is to describe the disparity of dental caries in the schoolchildren (talibes) of Daara of Koki. Method: A cross-sectional study was carried out on 400 talibes aged 7 to 12 years. Dental caries and socio-demographic data were, respectively, collected by clinical examination and questionnaire. Results: The sex ratio was 9, the mean age of 9.9 ± 1.5 years and the mean length of stay in the Daara was 2.3 ± 1.1 years. The prevalence of dental caries was 47.4%. The average mixed DFMT index was 1.1 ± 1.5. The prevalence was 51.2% among boys, 60% among eight-year-old children and 37.4% among twelve-year-old children. By length of stay, the prevalence was 52.9% at the start and 22.2% at the end with a significant downward trend (p < 0.0001). Conclusion: The study showed an unequally distributed of caries among talibes of Koki’s Daara. She suggests that oral health promotion policies are needed in Koranic schools and must rely on koranic teachers.


Introduction
School health is a global public health issue. School is a space where the child, still weakly prepared for the difficulties of life, is exposed to a particular social and psychosocial environment as well as to various influences that can shape his lifestyle and affect his health [1] [2]. School is also a place for education, for producing knowledge and for the construction of behaviors that can be beneficial to health [1]. Thus, the school environment has both positive and negative implications for student health in general and oral health [3].
In Africa, oral pathologies with their social and emotional implications in schoolchildren are a real concern [4] [5]. They affect the quality of life and cause absenteeism [6] [7]. One of the most common oral diseases is tooth decay. Its prevalence is estimated at 60.1% among students in a primary school in Ouagadougou in Burkina Faso [8], at 95% and 50.3% among 12-year-old schoolchildren, respectively, in the District of Bamako in Mali [9] and northern Kenya [10].
The distribution of dental caries is unequally distributed in children according to a social determinism with a more pronounced impact on the underprivileged layers [11]. In a 2015 study, Folayan et al. reported a prevalence of early childhood caries of 15.3%, 39.4% and 45.5% respectively in children of better, average, and lower socioeconomic status [12].
In Senegal, children's education is provided by the classical school, the Franco-Arab school, and the Koranic school (called Daara). The first represents formal education in the French language; it can be public or private. Daaras are primarily concerned with Islamic education and are generally private initiatives, made up of traditional Daaras and modern Daaras [13]. The dental health situation in Senegalese schools remains worrying. In schools in charge of formal education, the prevalence of caries has been estimated at 51.6% in 12-year-old Senegalese schoolchildren [14], at 64.8% in 3 to 9-year-old children. from the department of Pikine, a suburb of Dakar [15]. A review of the literature carried out in 2016, reported a social inequality in the prevalence of caries observed among schoolchildren in Senegal [16]. In the Daaras, to our knowledge, epidemiological data on dental caries are not available. However, the physical and social environment between the french classical school and that of the Koranic school may differ. This latter is generally more precarious. Several koranic schools are in a boarding school system where social living conditions are generally difficult, and the schoolchildren (called talibe) are cut off from their families [17].
This socio-educational environment is predictive of a dental health status that should be evaluated. This work aims to describe the disparities in oral health among the talibe of Daara of Koki.

Method
Type, setting, and study population A descriptive cross-sectional study was carried out. The study population was students aged 7 to 12 years old, selected among the children, presented at the

Sampling and sample size
A two-stage survey was carried out on the talibes. The first was to draw 40 groups of them at random out of 57 in the Daara; groups consisted of around 50 talibes. Then in each group, a draw of 10 talibes was made until the calculated size was reached. The sample size is calculated using Schwartz's formula (N = ɛ2.p.q/i2) where N represents the sample size; ɛ is equal to 1.96 for risk of error α of 5%; i corresponds to the desired precision of 0.05; p representing the prevalence, is theoretically estimated at 50% and q is the complementary probability, that is to say 1 − p. In total, N = 385, but rounded to 400 to avoid collection errors and any damaged files.

Study variables
The variables are formed from clinical data and socio-demographic factors.
The clinical data relate to dental caries, which corresponds to the presence of a clinically visible lesion.
It is assessed by clinical examination and described by prevalence and DMFT/dmft index. The socio-demographic data of the child are the sex (M/F), the age in years, the length of stay in the Daara in years, the child area of origin (rural/urban) and the frequency of financial support from parents (no/rarely/ frequently).

Collection of data
Data were collected using a questionnaire administered to talibes by a dental surgeon calibrated for this purpose. Through an interview with the talibe, the investigator provides information on socio-demographic data. He collects clinical data through an oral examination.

Analysis plan
The entry and analysis of data are done using the Epi info 7 software. This involved the calculation of frequencies for the qualitative variables, means and standard deviations for the quantitative variables. The distribution of tooth decay by talibes characteristics was tested by Pearson, Trend or Fischer Chi2.

Ethical aspects Open Journal of Epidemiology
The study was carried out after the authorization of the chief medical officer of the health district of Koki and the muslim chief of the Daara and moral officer of the talibes.

Results
Characteristic of the sample In total, 388 questionnaires, representing 97% of the sample, were analyzed. It is made up of 85.6% boys with a sex ratio of 9. The average age is 9.98 ± 1.5 years. Talibes had an average length of stay in the Daara of 2.3 ± 1.12 years and more than a third (34.3%) had spent two years. They had come to 65% from rural areas and 81.5% of parents sent money to children and only 36% did it frequently (Table 1).

Clinical data
The prevalence of dental caries was 47.4%. The average mixed DMF index was  (Figure 1). Caries prevalence is significantly different according to sex (p < 0.001); the risk of dental caries is higher in boys (51.2%) compared to girls; However, the prevalence of dental caries is higher among children from urban areas (53.7%) than that of children from rural areas (44%), but the reported difference is not significant (p < 0.070). According to the frequency financial support, the tests did not show a significant difference (p < 0.174) in the prevalence of caries (Table 1).

Discussion
This study describes the disparities in the prevalence of dental caries among ta- The results suggest a disparity in dental caries between talibes from urban areas and those from rural areas with a lower prevalence for these latter. Previous studies approach this by explaining it by the persistence of a natural diet that is less cariogenic and less risky behavior [22]. However, recent studies have reported the opposite conclusions supporting the importance of dental caries in African children living in rural areas compared to urban areas [23]. Indeed, the evolution of lifestyles associated with the increase in the prevalence of dental caries in Africa is a reality observed in both rural and urban areas. However, poverty is higher in the rural areas in Senegal; its social and health consequences for households do not spare children putting them at greater risk of dental caries [23] [24] [25].
The study suggests that talibes whose parents send money (frequent or rare) have more prevalence of dental caries than those whose parents never send money. This conclusion supports the literature which has largely established a significant correlation between the level of risk of dental disease occurrence and the amount of income [26] [27]. It assumes that income improves social conditions with its corollaries and makes it easier to obtain adequate oral hygiene products when needed [26].
The strengths of the study lie in the quality of the clinical data collected by a review performed by a professional. The large sample size is also strength in that it helps to highlight the differences that exist. One of the weaknesses of this study is the evaluation, in children by a questionnaire, of certain socioeconomic characteristics with potential classification bias. The scarcity of epidemiological data on the children of the Daaras makes comparison difficult.

Conclusion
Tooth decay among students at Koki Koranic School is still relatively high and shows disparities. Gender, area of origin and length of stay in Daara are factors that discriminate against decay among talibe. These results suggest that Koranic schools are suitable places for policies to promote oral health. The Daara of Koki is an example through the good initiatives developed in this direction. WHO recommendations on oral health in schools must be implemented in Daaras. Through a participatory approach based on proportion universalism, these actions will help to significantly reduce, if not eliminate, social inequalities in dental health in the Daaras.