Association Between Water Sanitation and Living Conditions and Dental Caries in Brazilian Schoolchildren

Objective: To analyze the association between water sanitation and living conditions and dental caries in Brazilian schoolchildren. Material and Methods: A list containing names of children enrolled in 18 urban public schools was obtained. Then, data registered by community health agents from the family health strategy were consulted, aiming to obtain information about socio-environmental variables such as house type, number of rooms in the house, water supply, water treatment, waste, feces and urine disposal. For sample calculation, 95% confidence level, 80% test power and 5% error rate were used A total of 199 5-yearold and 137 12-year-old schoolchildren participated in the research. For examinations, World Health Organization recommendations for epidemiological surveys of dental caries were followed. Results: For 5year-old children, dental caries prevalence was related to municipality of origin, water supply system and sewage system. For 12-year-old children, untreated water and waste collection were related to higher dental caries rates. Conclusion: Dental caries was associated to house type and water sanitation.


Introduction
Dental caries is the most common chronic disease in children and constitutes an important public health problem due to its high prevalence and individual and collective impact for causing pain, discomfort [1][2][3][4], nutritional impairment, deterioration of the general state and social and functional limitations that can affect children's quality of life [2,3,[5][6][7][8].
National data have shown that 53.4% of Brazilian children had caries disease in the primary dentition at the age of five, and at 12 years of age, 56.5% had the same condition in the permanent dentition. In this study, uneven dental caries distribution was observed, being worse in states of Northeastern and Northern Brazil, compared to those of Southern and Southeastern Brazil [9].
Studies have shown that caries disease affects populations unevenly [1,5,6,10,11]. While in the past, the focus of studies on dental caries was the relationship between biological and dietary variables in the process of the appearance of dental caries, in the last decades, there has been greater interest in researching how demographic and socioeconomic characteristics play a role in the prevalence of this disease in the population [2].
Access to fluoride in fluoridated water benefits mainly the most vulnerable children, because the caries-preventing power of fluorination is relatively more effective in situations of greater economic and social inequality. However, for the population to have access to treated water, sanitation should be implemented, thus guaranteeing a better quality of life for the population [5,11,17].
Housing and sanitation situations were recorded on forms used to register families by Community Health Agents (ACS), called Form A from 1996, whose objective was to use data in the planning and creation of strategies of health interventions by the primary care management, considering the real needs of the community [18].
Replacing form A, used by the Family Health Strategy (FHS), the Ministry of Health started to adopt e-SUS from 2013, and one of its items in the household register, whose purpose is to identify the socio-sanitary characteristics of households in the territory covered by Primary Care teams, in the housing conditions block [19].
Through home visits, it is possible to know the living conditions and surroundings, understand what guidelines are necessary for people to take better care of their health and improve their quality of life and to identify families that need more frequent or special follow up.
It is worth highlighting that, for the federal government, oral health was among actions of the community health agent. In the 2000/2003 Pluriannual Plan (PPA) bill, among the four indicators, dental caries reduction was included [20].
Even though the registration of families in Primary Care is being carried out throughout the Brazilian territory, the housing and sanitation situation is assessed, and little is known about its predictive potential for dental caries. In this context, this study aimed to analyze the association between housing and sanitation condition and dental caries in schoolchildren in the Family Health Strategy of two municipalities in the state of Minas Gerais.

Study Design
This is a primary cross-sectional and analytical study of epidemiological inquiry type, using secondary data to compose the independent variables to be analyzed.

Variables
Among housing and sanitation characteristics, this study considered only those present in Form A and e-SUS (Table 1). This option is due to the fact that data collection took place in 2012, when Form A was in force and the elaboration of this article took place when e-SUS was in force. Therefore, the findings of this research can be considered current.  [24,25].
Children whose parents did not allow their participation in the study or were not present in schools on the day of examination were excluded from the study, being replaced by other children of the same age.
Children aged 5-12 years were randomly selected and examined, which age group is adopted by the World Health Organization (WHO) for epidemiological surveys [26] in 18 public schools in urban areas. All children at this age group who agreed to be examined and were present at schools on the day of examination and whose parents / guardians signed the informed consent form were included in the study. Examinations were carried out in schools due to the easier access to children.
To evaluate dental caries in children, the DMF-T / dmf-t index was used, obtained by the sum of decayed, missing or with extraction indication due to caries injury and filled teeth [27] using # 5 flat mouth mirror and # 1 dental probe, without previous prophylaxis, in place provided of natural light.
Children were examined by a single previously calibrated examiner in each municipality (Kappa intraexaminer 0.82 for Brumadinho and 0.90 for Fortuna de Minas), according to WHO recommendations [28].
Examiners were assisted by an annotator and registration was performed in a specific and individual odontogram for each child.
Registrations of participants made by community health agents of the Family Health Strategy were consulted to obtain information on socio-environmental variables contained in Form A such as house type, number of rooms in the house, water supply, water treatment, waste, feces and urine destination.
For sample calculation, 95% confidence level, 80% test power, 5% error were used, as well as SB 2003 prevalence data [29] such as percentage of caries-free five-year-old children and DMF-T for those at the age of 12 years in the southeastern region; and population data from the Family Health Program of both municipalities in 2012. To assess socio-demographic conditions, Form A was used as instrument.

Results
Distribution of participants in the two municipalities, according to the age group and sample size, can be seen in Table 2. In addition, at the age of five, statistically significant relationships were found between presence of caries and water supply system (p=0.003) and type of sewage system (p=0.001). Children from Fortuna de Minas, with public water supply and official sewage collection, had lower caries prevalence in primary dentition (Table 3).  Table 4 shows associations between caries prevalence and variables related to 12-year-old children.
Statistically significant relationships were found for health variables such as water treatment (p=0.044) and waste collection (p=0.004) when associated with the M component of DMF-T. The "F" component of DMF-T was also associated with water treatment (p=0.034).

Discussion
At the age of 5 years, the following were associated with dental caries prevalence: municipality of origin, water supply system and sewage system. At the age of 12 years, absence of water treatment and waste collection were related to higher caries rates.
Five-year-old children living in Fortuna de Minas had higher caries prevalence when compared to those living in Brumadinho. In this case, the first possible explanation is due to the fact that there are differences in the Human Development Index (HDI) between these two municipalities. Brumadinho occupies the 599th HDI position, with value of 0.747, being considered high human development index, while Fortuna de Minas occupies position 2028, with value of 0.696, being considered medium human development [30].
This result corroborates some studies in the literature that also found worse oral health conditions in cities with low HDI [13]. In this study, HDI is an important indicator of social inequality because it presents, among others, income data [30].
The second explanation may be associated with the lower sewage rate in households of Fortuna de Minas, indicating worse quality of life. It is known that worst oral health situation is associated with worse quality of life [3,6].
The third possible explanation may be that the water from the public supply of Fortuna de Minas is not fluoridated, unlike Brumadinho, which has fluoridated water. Statistically significant relationship was found between use of well or spring and greater risk of caries in 5-year-old children (p=0.003). Of children who used well or spring as water supply, 56.0% had caries experience, while this same prevalence was approximately 60% lower in children assisted by the official water supply network. These findings confirm data from literature, which point to the consumption of fluoridated water as a protective factor against dental caries compared to populations deprived of water fluoridation [5,6,11,17].
In the present study, it was found that 12-year-old children who are not assisted by water treatment (p=0.044) and waste collection (p=0.004) have greater number of missing teeth. Similar results have been found in some studies [31,32], where water treatment was considered a potential factor associated with better oral health indexes.
In a study [33] on the use of dental services by children aged 5-9 years, access to waste collection and sewage treatment stood out. According to these authors, waste collection and sewage treatment are benefits directly related to housing conditions, that is, better financial conditions. Children who had benefits at home were The fact that municipalities were chosen for convenience and do not represent the set of municipalities in the State is a study limitation. In addition, the non-inclusion of the population living in the rural area means that children enrolled may not represent all the children in the municipality, especially at the age of five.
Another limitation is that only students who were present on the day of examination were included, with no second attempt to retrieve absent ones. However, this study has the potential of identifying variables of the social and economic environment that influence dental caries. The literature often does not include sanitation and housing factors on the dental caries experience. Variables associated with dental caries, such as water supply system, water treatment, sewage system and waste collection, indirectly represent quality of life and corroborate other studies [2,3,5,6,8] that even without using these variables, have shown similar results. The results found can help managers to better plan oral health actions.

Conclusion
Dental caries experience was associated with housing and water sanitation.

Financial Support
None.