Background

Oral and dental health is an integral part of complete health and well-being [1]. In most developing low-income countries, the prevalence of dental caries is high and more than 90% of caries are reported to be untreated [2]. Dental caries is the most common progressive chronic disease in school-age children with an increasing prevalence as children grow up [3, 4]. Recent trends relating to the increase in the prevalence of dental caries in children emphasize the need for more comprehensive measures as it is a preventable disease [5]. Oral and dental health in school-age children totally depends on oral hygiene behavior of children and their parents, dietary habits, parental education level, socioeconomic status, regular dental examination, adequate fluoride supplementation, oral microflora, age, and other demographic and cultural characteristics [3, 6, 7].

Caries risk assessment and determining leading risk factors enable effective prevention programs to be implemented at different levels (families, schools, institutions, local communities, etc.). In assessing a caries risk, a single method or model cannot simultaneously measure host resistance, microbial pathogens, and carcinogenicity of the diet. Therefore, caries risk should be assessed by analyzing and integrating several causal factors [8]. This study aims to examine the effects of socioeconomic status, oral and dental health practices, dietary habits, and anthropometric measurements on dental health in 12-year-old school children, and unlike the other studies, many factors involved in the etiology of dental caries were assessed together.

Methods

Research sample and design

The sample of this study was composed of a total of 254 voluntary 12-year-old school children (44.1% boys and 55.9% girls) enrolled in three different middle schools (low, moderate, and high socioeconomic level) in Turkey. The World Health Organization develops basic methods and criteria for use in oral and dental health field surveys and recommends the use of specific age or age bands to make comparisons between countries. It is stated in the “basic principles” of the World Health Organization that it is sufficient to select 5 years of age to determine the condition of milk teeth and to select sample among 12- and 15-year-old children who have different risks to determine the condition of permanent teeth in childhood. This study was carried out with 12-year-old children due to the fact that all permanent teeth except for the third molars should erupt until 12 years of age and this age group is a global indicator age group for monitoring international comparisons and disease trends [9]. The study was conducted with the approval of the Ethics Committee of Mardin Artuklu University dated 11.01.2018 and no. 2018/01-3.

Data collection tools

The data were collected by face-to-face interviews via a questionnaire form including socioeconomic status, oral and dental health practices, dietary habits, and anthropometric measurement. Children’s height (cm), body weight (kg), waist circumference (cm), hip circumference (cm), upper middle arm circumference (cm), triceps skinfold thickness (mm), and biceps skinfold thickness (mm) were taken in accordance with the technique. Waist circumference ≥ 84.5 cm for boys and ≥ 81.9 cm for girls were considered “risk”, but the ones below these values were considered “normal” [10]. Waist-to-height ratios were classified as “take care” if < 0.4, “normal” if 0.4–0.5, “take care” if 0.5–0.6, and “take action” if ≥ 0.6 [11]. Body mass index (kg\m2) was classified as < 3 “too weak”, ≥ 3–< 15 “weak”, ≥ 15–< 85 “normal”, ≥ 85–< 97 “overweight”, and ≥ 97 “obese” according to the 12-year-old table of percentiles [12].

Clinical examinations were performed by a dentist to assess the oral and dental health of the children. The dentist determined the number of teeth affected by caries and its results for each child and marked them in the oral examination form. The sums of the number of decayed teeth (DT), missing teeth (MT) and filled teeth (FT) (decayed, missing, and filled teeth: DMFT), and teeth surfaces (decayed, missing, and filled surfaces: DMFS) were calculated. DMFT and DMFS indices of the children were determined as a result of these calculations. dmft and dmfs indices were used for milk teeth. The missing teeth were not included in the examination for milk teeth. The dental caries levels of the children were determined using WHO classification based on the means DMFT and dmft (< 1.2 “very low”, 1.2–2.6 “low”, 2.7–4.4 “moderate”, 4.5–6.5 “high”, and > 6.5 “very high”) [9].

Statistical analysis

SPSS (Statistical Package for the Social Sciences) package program was used to analyze the data. Chi-square and Fisher’s exact chi-square tests were performed to determine whether there was a significant relationship between qualitative variables. Mann-Whitney U test was used to analyze the means between the two groups that did not show normal distribution, and mean (X̅), median, standard deviation (SD), and upper and lower values were shown. Kruskal-Wallis variance analysis was used to analyze the means among the three and more groups. Kruskal-Wallis hypothesis test was applied to uncover which group caused the difference. Spearman correlation was used to determine the relationship between the factors affecting oral and dental health indicators. Statistical significance was evaluated at p < 0.01 and p < 0.05. The confidence interval for all statistical tests was adopted as 95.0%.

Results

A total of 254 12-year-old children (44.1% boys and 55.9% girls) participated in the study. It was found that 70.9% of the children have dental caries on their permanent teeth and 44.1% of them have at least one caries on their milk teeth. Moreover, it was found that the number of girls who have caries on their permanent teeth and boys who have caries on their milk teeth is higher (p < 0.05). dmft and dmfs indices were found to be very low in 47.2% and 75.2% of the children, respectively. It was discovered that low DMFT rates (girls 20.5%, boys 9.8%) were higher in girls and high dmft rates (girls 2.1%, male, 9.8%) were higher in boys (p < 0.05) (Table 1).

Table 1 Classification of indicators of permanent and milk teeth of children
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It was found that nearly all of the children brush their teeth (96.1%) and the number of those who do not brush their teeth (7.9%) is higher among ones the with low socioeconomic status (p < 0.05). 34.3% of the students reported that they brush their teeth once a day and 21.7% reported they sometimes brush their teeth. The number of those who brush their teeth several times a week (10.1%) is higher among the ones with moderate socioeconomic status and the number of those who brush their teeth three times a day (6.3%) is higher among the ones with high socioeconomic status (p < 0.05). Nearly half of the children (49.2%) stated that they first saw a dentist at the age of 6–10 and 14.2% reported that they have never seen a dentist. It was found that the number of those who see a dentist 1–2 times a year (30.0%), have previously received oral and dental health education (65.6%) and change their toothbrush every 3 months (43.8%) is higher among the ones with high socioeconomic status (p < 0.05). It was discovered that 39.0% of children have harmful oral and dental health habits in which lip bite (62.6%) is the leading (Table 2).

Table 2 Information on oral and dental health of children
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There are 1.7 ± 1.78 decay, 0.1 ± 0.35 missing, and 0.2 ± 0.69 fillings in permanent teeth of the participants. The mean numbers of decayed and filled milk teeth are 1.0 ± 1.49 and 0.5 ± 0.36, respectively (data not shown). The mean DMFT is 2.0 ± 1.90, and dmft is 1.0 ± 1.57. dt, dmft, ds, and dmfs values of boys were found to be higher than of girls (p<0.05). It was determined that those who brush their teeth, brush their teeth after the meal and before bedtime, brush in a circular style, and change their toothbrush every 3 months have better oral examinations (p > 0.05). Those who brush their teeth three times a day (DMFT 1.3 ± 1.42, dmft 0.0 ± 0.00) have better permanent (p > 0.05) and milk teeth (p < 0.05) examination than sometimes brushers (DMFT 2.4 ± 2.02, dmft 1.5 ± 1.93). According to the brushing duration, those who brush their teeth for 2–3 min have the minimum mean DMFT values (1.8 ± 1.70) (p > 0.05) and it was found that those who brush more than 3 min (0.2±0.58) have lower mean dmft values than those who do not know their brushing duration (1.9±1.20) (p < 0.05) (Table 3).

Table 3 Oral Health Indicators According To Gender and Oral/Dental Health Practices
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Those consuming crackers, cornflakes, bread, flavored milk, dried fruit, instant fruit juice, fizzy drinks, iced teas, energy drinks, dessert, candy\delight etc., pastry products, jam, table sugar, jelly food, and sugary chewing gum have higher mean DMFT values than those who do not consume such foods and drinks, but the differences are not statistically significant (p > 0.05). Considering the mean dmft values, those who do not consume crackers, chips, bread, dried fruit, instant fruit juice, fruity drinks, fizzy drinks, energy drinks, dessert, cookies, cakes, pudding, biscuits, chocolate, table sugar, jelly foods, and sugary chewing gum have lower mean dmft values and the differences are statistically significant only for molasses and table sugar (p < 0.05) (Table 4). The mean duration of breastfeeding of children is 14.1 ± 7.46 months and the mean time of starting complementary feeding is 6.1 ± 1.64 months. It was determined that children with low socioeconomic status have less breastfeeding time (p < 0.05), and oral and dental health indicators do not differ according to breastfeeding time and the time of starting complementary feeding (p > 0.05) (data not shown).

Table 4 Oral health indicators of children according to their nutrient consumption status
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It was discovered that there is a negative relationship between waist-to-height ratio and FT; between waist circumference and FT and DMFT; between hip circumference and DMFT (p < 0.05). It was also found that there is a negative relationship between dt and body mass index, hip circumference, upper middle arm circumference, biceps skinfold thickness, and triceps skinfold thickness (p < 0.01); and between ft and hip circumference (p < 0.05). There is a negative relationship between dmft and Body Mass Index, waist circumference, hip circumference, upper middle arm circumference, biceps skinfold thickness, and triceps skinfold thickness (p < 0.01) (Table 5).

Table 5 Correlation between oral health indicators and children’s anthropometric measurements, socioeconomic status, and educational status of parents
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Discussion

The present study was conducted with a total of 254 12-year-old children enrolled in three different middle schools (high, moderate, and low socioeconomic status) to examine the effects of socioeconomic status, oral and dental health practices, dietary habits, and anthropometric measurements on oral and dental health.

Oral and dental health in school-age children totally depends on such factors like oral hygiene behavior of children, dietary habits, socioeconomic status, regular dental examination, age, and other demographic and cultural characteristics [3, 6, 7]. Socioeconomic factors have become increasingly scrutinized in studies as they affect the prevalence of dental caries, oral health practices, and parental knowledge on oral and dental health [13, 14]. It is stated that families with high socioeconomic status behave more conscious about their children’s dental health [15]. In this study, it was shown that factors affecting oral and dental health, such as tooth brushing practices, age, and frequency of seeing a dentist and oral and dental health education vary by the one’s socioeconomic status. Oral and dental health practices were found to be better in the children of families with high socioeconomic status (Table 2). Similarly, in other studies, children with high socioeconomic status are more likely to see a dentist [4, 16] and to have higher rates of regular brushing [17]. The fact that children from higher-income households have more chances to access to dental care, including a more specific diagnostic assessment and have one or more filled teeth explains the difference in oral and dental health by the ones’ socioeconomic status. Higher prevalence of caries in lower socioeconomic status may be due to lack of prevention and treatment services most of the time. It is important that both children and their parents with low socioeconomic level are educated in oral health, awareness raising, and guided to make more use of treatment services.

Oral and dental diseases are seen different rates in every society and ages. The World Health Organization and the World Dental Federation (FDI) recommended that DMFT should not be more than 3 for 12 years until 2000, as one of the global goals for oral and dental health [18]. In this study, the mean DMFT value is 2.0 ± 1.90 and the recommended goal was reached. Considering certain studies conducted by countries, the mean DMFT values were determined as 4.8 ± 3.22 in Bosnia and Herzegovina [8], 0.14 in Nigeria [17], 3.3 ± 2.3 in Russia and 0.5 ± 0.8 in Norway [7], and 1.64 in Thailand [19]. Dental caries were determined in 70.9% of the children in the general sample, 61.6% of boys and 78.2% of girls (p < 0.05) (Table 2). There was no significant difference between gender and the mean DMFT\dmft value which was found to be 1.9 ± 2.2 in 12-year-old children in the Study for Oral and Dental Health Profile of Turkey [20]. In parallel with this study, although there are other studies revealing that the mean DMFT in girls is higher [3, 21], it was determined in some studies that oral and dental health indicators were similar by gender [7, 16, 22]. It is stated that the prevalence of caries may be higher due to the earlier ages for dentition in girls and the emergence of periodontal problems due to hormonal changes in puberty period.

Since dental caries has a multifaceted etiology including general health, nutrition, plaque, saliva secretion, type and amount of microorganism, sensitivity of host, oral hygiene habits, use of fluoride, social and behavioral factors, any relationship between oral and dental hygiene practices and caries is difficult to be detected [23]. In this study, it was found that the indicators for milk teeth of those who have higher tooth brushing time and frequency are better (p < 0.05) (Table 3). Proper oral and dental hygiene is also effective in preventing many diseases that are not associated with caries. The most common diseases such as caries and periodontal diseases are caused by poor oral hygiene practices as well as other factors [24], and children are important to be educated in subjects such as brushing style, duration, and frequency.

Dietary habits play an important role in general health status and oral health [25]. In one study, the predominant factor in caries risk profile was shown to be diet [8]. In this study, the mean DMFT\dmft values of the children consuming foods with high cariogenic potential were determined likely to be high (Table 4). In a study conducted to examine the effect of backward dietary habits of children on dental health, those who consumed foods increasing the risk of dental caries more than three times a day at the age of one and those who consumed candy more than once a week at the age of 3 were found to have higher number of decayed and filled teeth at the age of 15 [26]. The negative relationship between nutritional status and caries is explained by main meals and snacks. Main meals are stated to contain higher protein and fat and lower sugar than snacks so that snacks are associated with caries. While being exposed to sugary and starchy foods during meals reduces the risk of caries, it was revealed that high sugar consumption with snacks increase such risk.

Dental caries, obesity, and malnutrition are global diseases with adverse effects on health [27, 28]. As there are common risk factors for these diseases, the relationship between body weight and tooth decay has been the subject of many studies [29,30,31,32]. People who have an unbalanced diet with low nutritional value and high sugar and energy content are often affected by both malnutrition and caries. In addition, it is stated that there is a positive relationship between obesity and dental caries with increasing food and refined food consumption and consumption frequency. Therefore, it was investigated whether there is a causal relationship between dental diseases and anthropometric measurements or whether they share the same risk factors [2]. In this study, a negative relationship was found between anthropometric measurements and oral and dental health indicators (Table 5). Contradictory results were found in both research and review studies on body weight and oral health in children. Some studies showed a positive correlation between body weight and tooth decay [26, 33,34,35], some of them revealed a negative relationship [3, 6, 36], and others found no relationship between them [16, 37,38,39]. Besides, different results were reached according to different age groups [19, 40]. A negative relationship between anthropometric measurements and tooth decay may be caused by the risk of a weak immune system and dietary habits based on foods with low nutritional values and high energy foods in children with low body weight. The difficulty in studying the relationship between dental caries and obesity is due to the fact that many factors need to be measured at the same time in a standard way.

Conclusions

It was revealed in this study that dietary habits, anthropometric measurements, oral and dental health practices, gender, and socioeconomic status are effective on caries. It is recommended that children and parents with low socioeconomic status should be given education on oral and dental health practices and guidance to dental care services should be increased. Regulation of dietary habits of children is considerable both for anthropometric measurements and prevention of dental caries. In assessing the effect of dietary habits on dental health, the amount and frequency of consumed foods should be examined in more detail.