Association between feeding habits and severe - early childhood caries in children up to 24 month old

Abstract Introduction During the first two years of life children’s nutrition is mostly based on frequent, liquid and sweetened meals which can cause Severe-Early Childhood Caries (S-ECC) development. The aim of this research was to determine the relationship between dietary habits and S-ECC in children up to 24 month-old living in Banja Luka, Bosnia and Herzegovina. Methods Cross-sectional study included representative sample of 192 children. Before dental examination of children, each parent/caregiver was interviewed about the basic info, socio-demographic characteristics and children's eating habits. The questionnaire was conducted as interview (“face to face”). Subjects were divided into two groups: the first group - children with S-ECC and the second group - caries free children. For statistical analysis and presentation of results SPSS 16.0 for Windows, MS Office Word and Microsoft Office Excel were used. Results In the study sample 34.9% of children were suffering from S-ECC. About 50% of children who were breast-fed at night after first tooth eruption had S-ECC. The use of baby bottle with milk or other sweetened content during bedtime and during the night was identified as significant caries risk factor (P <0.05). Conclusion Nighttime breastfeeding, use of bottle with milk during bedtime/nighttime or other sweetened content during night after eruption of first primary tooth were strongly associated with S-ECC in the examined children.


INTRODUCTION
Early childhood is crucial for proper development and maintaining oral health. Early childhood caries (ECC) is one of major public health problems in the world [1][2][3][4][5][6][7]. According to the research it is one of the most common chronic infectious disease in early childhood that is due to its multifactorial etiology difficult to control [8,9].
Aggressive form of the disease -Severe Early Childhood Caries (S-ECC) can occur as soon as the deciduous tooth appears in the mouth, with localization on caries immune sites or smooth surfaces of the tooth [10]. The disease mostly begins as an off-white chalky change on the vestibular surface of the enamel along the gum line and sometimes on oral surface of primary maxillary incisors. Caries destruction of the tooth can be quite rapid and soon it can spread on other teeth. If child does not receive an appropriate treatment the disease can lead to pulp involvement, pain and other complications.
Similar to other forms of tooth decay S-ECC etiology includes interaction of three main factors: cariogenic microorganisms, fermentable carbohydrates and a host (tooth) during period of time [11]. Besides, specificities of an early age, like immature immune system, newborn teeth in the stage of post eruptive mineralization, hy-poplastic changes, a special type of food (mostly liquid based) are considered to be risk factors for S-ECC development [12,13]. In addition to primary risk factors, there is a wide range of secondary factors that can indirectly contribute to development of carious lesions in primary teeth, but they are still under investigation [8][9][10].
Breastfeeding is natural, desirable type of feeding of a newborn and undoubtedly has great impact on overall health and development. Human milk is specific and its composition ideally suits human babies, opposite to substitutions of different origin (adapted infant formula, animal milk) that differs greatly in content. Breastfeeding is of great significance for proper growth, it provides optimal nutritional ingredients, immune protection to infants, and minimizes economic impact on families. The World Health Organization recommends breastfeeding until 24 months of age [14]. However, the American Academy of Pediatric Dentistry (AAPD) recommends that breastfeeding should stop around 12 months of age, even before, as soon as the first primary tooth erupts (around six months of age), because they consider that a longer duration of this habit contribute to development of an aggressive form of Early Childhood Caries (S-ECC) [10].
Children's diet in the first two years of life is mostly based on frequent, liquid and often sweetened meals.
A special role in the etiology of dental caries in early childhood plays an inappropriate use of baby bottle especially during bedtime and nighttime. When a child falls asleep, liquid from a bottle is poured onto maxillary incisors, representing an outstanding basis for the development of cariogenic bacteria, especially because during the night the secretion of saliva is reduced [15].
In Banja Luka, Republic of Srpska, there is no organized prevention program in dentistry. There is no systematic oral health promotion and education of parents, there is lack of data regarding dental pathology and related risk factors in an early age because the practice of the first dental visit around the first birthday is not yet established. Unfortunately, the first dental examination is required only when enrolling into primary school.
The aim of this study was to determine relationship between dietary habits and development of Severe-Early Childhood Caries (S-ECC) in children up to 24-month-old living in Banja Luka, Bosnia and Herzegovina.

MATERIAL AND METHODS
The survey was conducted among children up to 24 month old, between July 2012 and July 2013. The crosssectional retrospective study included 192 children of both genders that represented 10% sample (even slightly larger) of a total of 1,820 children born and living in the city of Banja Luka during the period of 2011 to 2012. The study was conducted in the Public Health Center of Banja Luka. Necessary approval of the General Director and Ethical Committee of the Public Health Center of Banja Luka was obtained before the initiation of research.
Inclusion criteria of the study were: the presence of at least two fully erupted primary teeth in a healthy child and parental consent for participation. Respondents were selected randomly. Healthy children who were visiting regular pediatric checkups in Public Health Center of Banja Luka were referred to the specialist of pediatric and preventive dentistry for the evaluation of risk factors for Severe Early Childhood Caries. First dental visits of children were conducted in a separate office near the pediatric ambulance of Public Health Center. Every child was examined and parent interviewed, but only children who passed the inclusion criteria were included in further research.
Before dental examination of a child, a parent/caregiver was interviewed. A total of 192 questionnaires was filled and subsequently analyzed. Interviews were conducted "face to face" by a single researcher. Questionnaire consisted of two separate parts: the first contained questions related to general information of patient, sociodemographic information, dietary information such as breastfeeding and use of bottles. The second part was Dental record. Issues related to eating habits (breastfeeding and use of bottle) as possible risk factors for S-ECC were considered for the period after primary tooth eruption. Milk bottle referred to infant formula or animal milk (cow milk), and other sweetened content involved juices, milk porridge or sweetened tea. Research questionnaire was formed according to the guidelines of the American Academy of Pediatric Dentistry (AAPD) [16].
After completion of the interview, dental examination of children was conducted in the office with good natural light. Dental examinations were done in "knee to knee" position where parent and dentist seated opposite to each other so the child was lying with body and legs on the parent's lap, while the head was on the dentist's lap [17]. Oral examination was done using dental mirror and CPI periodontal probe (CPI-Community Periodontal Index). Sterile gauze swabs were used to dry the teeth, and remove dental biofilm. Carious changes on infant's teeth were diagnosed using the International Caries Detection and Assessment System (ICDAS), which is used for diagnosis and records of initial "white spot" carious lesions (without formed holes) to observable carious cavity [18]. Every surface of the tooth was examined and recorded in the second part of the Research Form. Only teeth that were fully present in one's mouth and all crown surfaces visible were taken into consideration.
After data collecting respondents were divided into two groups for the purpose of further analysis and assessment of S-ECCC risk factors. The first group consisted of children who had S-ECC (children with at least one active initial carious lesions on smooth surfaces of maxillary anterior teeth, according to AAPD) and the second group included completely healthy individuals without caries lesions (caries-free children) [10].
For statistical analysis and presentation of results SPSS 16.0 for Windows, MS Office Word and Microsoft Office Excel were used. The results were analyzed statistically by the Fisher's exact test, χ2 test (for checking linear growth), and binary logistic regression. Values of p <0 .05 were considered statistically significant.

RESULTS
A total of 192 children were examined, 99 (51.6%) boys and 93 (48.4%) girls up to 24 months of age. The prevalence of S-ECC in the sample was 34.9%.
Socio-demographic characteristics of families are presented in the Table 1. Majority of mothers (n = 117) had secondary school education or lower, which was significant for the occurrence of S-ECC. About 71.87% of fathers also had secondary or lower school education, but this was not significant for the prevalence of caries in the examined sample. Monthly income below 1600 KM -Convertible Marks (< 818, 06 euro) reported 79.69% of families.
Most of examined children (89.58%) were breastfed for at least one month (n = 172). There was no statistically significant difference in the S-ECC presence between children who were breastfed (34.3%) or not (40.0%) ( Table  2). The children who were breast-fed four times per day or more (n = 41) were affected more by S-ECC (36.6%) compared to those who had lower frequency of daily feedings (33.6%) but this was not significant ( Table 2). A half of respondents (50%) who were breast-fed during the night had S-ECC. About 73.3% of those with S-ECC were breast-fed more than two times during the night. This was statistically significant ( Table 2). S-ECC was present in 50% of children practicing bedtime baby bottle with milk (Table 3). Children who consumed sweetened liquid (64.7%) or milk (54.2%) in bottle during nighttime were also significantly more affected by S-ECC (Table 3).

DISCUSSION
The prevalence of ECC varies from 1% to 70% in different parts of the world and can be affected by many factors [2,3,19,20]. A survey conducted in Banja Luka from 2008 to 2010, among 2 to 6 year-old children attending the Centre for pre-school education of Banja Luka, demonstrated high prevalence of dental caries (35.35 %) where carious lesion was diagnosed on a level of already formed carious cavity. The largest percentage of affected teeth (92.69%) was not treated [21]. However, this study did not cover children at infancy (up to 24 months-old) that is from the point of primary prevention the most important and initial caries lesions were not registered either. Leong et al. confirmed that factors occurring in the first year of life strongly influence the experience of early teeth decay, which particularly can be related to the eating habits of a child [9].
The prevalence of caries lesions in our research was high and included 34.9% of all respondents. Most of children came from families whose incomes were below average, considering that even 79.68% of the surveyed families had a monthly income less than 1600 KM (below 818.06 euro). According to the data of the Republic of Srpska Institute of Statistics the average monthly net salary in the Republic of Srpska was around 825 KM (421.81 euro) [22]. This study shows a significant association between the occurrence of S-ECC and socio-economic status of the family, which is consistent with previous studies [2,9,23].
Studies of various researchers have shown that milk and dairy products have multiple benefits for oral health [24,25]. Their role in prevention of dental pathology, such as caries and periodontal disease is well documented. It has been showed that milk contains a variety of bioactive peptides, as well calcium that play a key role in maintaining good health of teeth [24,25]. Recent study, among preschoolers, shows that children who were not breast-fed were at increased risk for the development of hypoplastic enamel changes [26]. It has also been found that the act of sucking of mother's milk greatly contributes to the proper formation of the stomatognathic system of infants [25].  Besides undoubtedly great positive impact on oral health in the literature, there is evidence that human milk under certain conditions, like frequent (on demand) or nighttime feedings after the eruption of primary teeth, leads to acidogenic and cariogenic conditions that contribute to S-ECC [27,28]. In our study, breastfeeding was not systematically related to the prevalence of S-ECC in the examined children, even frequent daily feedings (more than four times a day) after the eruption of the first primary tooth. Iida et al. found no relationship between breastfeeding, or duration of this habit with the prevalence of S-ECC in children aged two to five years of Mexican-American origin [29]. Nilza and Manoel Ribiero found no reliable scientific evidence to support the hypothesis of human milk cariogenicity, because it is very complex relationship often masked with other potentially cariogenic variables [13]. On the other hand Li et al. and Matea et al. in their research reported significant association between prolonged and frequent breastfeeding on demand and S-ECC [2,12]. In the further course of our study we showed that frequent nighttime breastfeeding (or in general practice of nighttime breastfeeding) significantly led to the emergence of S-ECC. Azavedo et al. also showed a link between breastfeeding habits at night (after the age of 12 months) and higher prevalence of S-ECC on a sample of preschool children [23]. Vachirarojpisan et al. reported the prevalence of S-ECC of 58.4% in children 6 to19 month-old in Thailand. He also showed a significant association between disease and prolonged and frequent breastfeeding, low-income parents, low level of mother's education, high levels of Streptococcus mutans in the mouth, and practicing night meal with bottles [3]. Santos and Soviero in children under 36 months old showed the prevalence of dental caries (including "white spots") was 41.6%. They found significant association between the incidence of dental caries and socio-economic status and practicing night meal (bottle or breast feeding) [20].
A large number of children in our study have been using a baby bottle with milk or other sweetened content at bedtime and during the night and that was significantly associated with the occurrence of S-EEC. This is an indicator of poor oral health education of parents who are not aware about harmful effects of such habits. Therefore we believe there is need for introducing obligatory oral health education of parents. Also dental visit of a child around 12 months of age should become legal obligation in Banja Luka and throughout Republic of Srpska. The American Academy of Pediatric Dentistry (AAPD) and the European Academy of Pediatric Dentistry (EAPD) suggest that regular first dental examination of a child should be done no later than one year of life [10,30]. In the scientific literature there is evidence that suggests that counseling and education of parents about nutrition, oral hygiene and other risk factors contribute to lower prevalence of S-ECC [31].

CONCLUSION
The prevalence of S-ECC in examined children up to 24 month-old in Banja Luka is high and it is associated with nighttime breastfeeding, use of baby bottle with milk during bedtime/nighttime and use of baby bottle with other sweetened content during nighttime after eruption of the first primary teeth. It is necessary to introduce mandatory first dental examination of a child around the first year of life as well as to organize oral health-education of parents.