One of the most common infectious diseases related to nutrition is tooth decay. In this study, the relationship between diet and obesity with tooth decay in children was investigated. This descriptive-analytical study was conducted on children. Tooth decay was determined by the DMFT index. Also, BMI (Body Mass Index) was used to evaluate obesity, and a semi-quantitative FFQ (Food Frequency Questionnaire) was utilized to evaluate food intake. The results showed that the frequency of caries index in overweight and obese children was significantly higher than in other children (P < 0.05). The results of the frequency of food consumption showed that all children, except for the milk and dairy group, used fruits and vegetables from other food groups. An inverse correlation was observed between tooth decay and the average consumption of milk and dairy products, fruits, and vegetables, and a significant positive correlation was observed between BMI and the frequency of consumption of sweets. In the current study, obesity, consumption of carious snacks, and reduction in consumption of vegetables, fruits, and dairy products have been proposed as risk factors for dental caries in children. Due to the importance of teeth in children's general health, it seems necessary to educate parents and children about following a balanced diet.
Introduction
Dental caries is one of the most common chronic childhood diseases [1-4] and a practical health problem in developing countries [5-7]. Various factors such as genetic factors, nutritional status, obesity, dental anatomy, oral hygiene, use and absorption of fluoride, age, gender, composition and amount of saliva secretion, parental education level, and socio-economic status have been suggested in causing tooth decay [4-8]. Studies have shown that childhood nutrition is related to most diseases in adulthood [9, 10]. At the same time, research shows that diet has an effective role in the occurrence of obesity, premature loss of teeth, gum problems, and bad breath [11, 12].
Carbohydrates are a suitable substance for bacteria that cause tooth decay. Sucrose-rich foods and the frequency of food consumption cause the microbes in the mouth to break down sugary substances. For this reason, the acid caused by the bacterial fermentation of simple carbohydrates lowers the pH of saliva and provides the basis for caries. The longer the contact time of sugary substances with the oral environment, the more damage occurs. Therefore, sticky sweet substances such as raisins, dried berries, and chocolate have more destructive effects [13, 14]. This is especially important in children [5, 6].
Correct and appropriate nutrition from the beginning of life not only improves the physical growth and development of the child [9] but also has a major effect on the optimal health of the oral cavity and the general health of the child [15, 16]. Sweetening children's food makes the child's sense of taste accustomed to sugary substances, and this shows a greater interest in consuming sweet substances at an older age. Improper nutritional patterns among children and adolescents, especially sweet snacks, most of which are taken outside the home, lead to this age group being more at risk of obesity, overweight, and tooth decay [3, 4].
Obesity is one of the most common nutritional disorders associated with dental caries in children [4-6]. In some research, a positive and significant relationship between obesity and dental caries has been reported [4]. However, in some studies, an inverse relationship has been reported [8] and in some studies, no relationship has been reported [3, 5]. Considering the importance of healthy nutrition and the possible role of obesity in causing tooth decay, this study was conducted to determine the relationship between food intake and obesity with tooth decay in children.
Materials and Methods
The current study was cross-sectional and descriptive and was conducted on 79 children (47 girls and 32 boys). The sample size was estimated based on the formula used in cross-sectional studies, taking into account the prevalence of tooth decay of 82%, maximum error of 8%, and alpha of 0.05. First, the purpose of the research was explained to the mothers of the investigated children, and if the children agreed, they were included in the plan.
Tooth decay was determined using the DMFT (Decayed, Missing, and Filled Teeth) index, which is a sign of restored and extracted decayed teeth. For this purpose, the teeth were examined by dentists based in the pediatric dental clinic using a dental unit, a probe, and a flat dental mirror. To classify the severity of tooth decay, DMFT methods of zero (no decay), 1-3 (low decay group), and DMFT ≥ 4 (high decay group) were considered.
Body mass index was used to evaluate obesity. For this purpose, the weight of children with minimal clothes and without shoes was measured with a Bascoli scale (Seca/Germany) with an accuracy of 100 grams and height with a Seca caliper with an accuracy of 0.5 cm. Body mass index (BMI) is calculated from the division of weight (kilograms) by the square of height (square meters), calculated using the percentiles of body mass index, for age and sex, set by the US Centers for Disease Control and Prevention (CDC) [17]. Due to the small number of samples in this study, children were classified into 3 groups based on BMI percentiles: children with BMI less than 5th percentile, as underweight; between 5-85th percentiles were considered as normal, and children with a percentile above 85th were considered overweight and obese Semi-quantitative food frequency questionnaire (FFQ) to evaluate children's food intake based on the main food groups included A list of 142 food items in the groups of grains, dairy products, proteins, fruits, and vegetables, as well as other foods, including sweets (sugar, honey, jam, biscuits, cakes, cookies, sweets, chocolate, and candies), snacks and other low-value food items (chips, pretzels, pretzels) and sweet and carbonated drinks (carbonated drinks, desserts, and industrial fruit juices) were completed by nutrition experts through face-to-face interviews with mothers. The validity and reliability of the food frequency questionnaire were done in a previous study.
Data analysis was done using SPSS version 23 statistical software. Considering the normality of the data, the χ² test was used to analyze the qualitative variables, and the one-way ANOVA test was used to analyze the quantitative variables related to tooth decay. Also, to determine the correlation between the DMFT index with background variables and food groups, Pearson's correlation test was used. P<0.05 was considered as a significant level.
Results and Discussion
79 children (47 girls and 32 boys) aged 6 to 11 years with an average age of 9 ± 1.9 years were studied. The results showed that in all the samples, 20 children (25.3%) had normal weight, 20 children (25.3%) were underweight, and 39 children (49.4%) were overweight and obese. The average DMFT index in all samples was 3.97 ± 1.6. 71 (89.9%) of the studied children had tooth decay. 8 (10.1%) of the children had zero DMFT (no decay), 37 (46.8%) had DMFT 1-3 (low decay), and 34 (43.1%) had DMFT 4 and above (high decay). The highest percentage of fathers were employees (57%) and had a diploma and higher education (65.8%) and the highest percentage of mothers were housewives (69.6%) and had a diploma and higher education (54.4%). The average size of the household was 5.3 ± 1.3 people.
Table 1. Frequency distribution of body mass index and severity of dental caries in the studied children.
|
DMFT BMI |
0 |
1-3 |
≥ 4 |
Total |
||||
|
N |
% |
N |
% |
N |
% |
N |
% |
|
|
Low weight |
2 |
25 |
11 |
29.7 |
7 |
20.6 |
20 |
25.3 |
|
Normal |
3 |
37.5 |
11 |
29.7 |
6 |
17.6 |
20 |
25.3 |
|
Overweight/Obese |
3 |
37.5 |
15 |
40.6 |
21 |
61.8 |
39 |
49.4 |
|
Total |
8 |
100 |
37 |
100 |
34 |
100 |
79 |
100 |
As shown in Table 1, caries severity showed a significant relationship with body mass index (p = 0.05; X² = 7.2), so that 21 (8.61%) of the children who were overweight or obese had DMFT greater than or equal to 4. The average food groups consumed and their relationship with the severity of tooth decay are summarized in Table 2. The results showed that the average consumption of milk and dairy products (P = 0.02) as well as fruits and vegetables (p = 0.04) had a significant relationship with the severity of tooth decay.
Table 2. The average food groups consumed and the severity of tooth decay in the studied children.
|
The severity of tooth decay
Food groups |
0 (Mean ± SD) |
1-3 (Mean ± SD) |
≥ 4 (Mean ± SD) |
P |
|
Milk and dairy products |
2.3 ± 1.8 |
1.5 ± 1.2 |
0.7 ± 0.09 |
0.02 |
|
Fruits and vegetables |
2.6 ± 1.5 |
2.4 ± 1.7 |
1.9 ± 1 |
0.04 |
|
Bread and cereals |
5.7 ± 2.3 |
5.8 ± 1.9 |
5.6 ± 2.1 |
0.55 |
|
Meats, legumes, and eggs |
2.3 ± 0.9 |
2.3 ± 1.3 |
2.1 ± 0.9 |
0.35 |
Tables 3 and 4 show the frequency of consumption of milk and dairy products, fruits and vegetables, and decay-causing foods (including sweets, snacks, and sweet and carbonated drinks) in the studied children. As can be seen, most children (65.8%) only used milk and dairy products (P = 0.03; χ² = 15.2), fruits and vegetables (P = 0.02; χ² = 11.3) 1-2 times a week, while the consumption of sweets (P = 0.03; χ² = 23.2), sweet and carbonated drinks (P = 0.06; χ² = 19.7), and snacks (P = 0.055; χ² = 32.3), were more and equal to 5 times a week in most children.
Table 3. Frequency distribution of consumption of milk and dairy products, fruits, and vegetables in the studied children.
|
Frequency of consumption
Food intake |
Never |
1-2 times a week |
3-4 times a week |
≥ 5 times a week |
χ² |
P |
||||
|
N |
% |
N |
% |
N |
% |
N |
% |
|||
|
Milk and dairy products |
10 |
12.7 |
52 |
65.8 |
9 |
11.4 |
8 |
10.1 |
15.2 |
0.05 |
|
Fruits and vegetables |
14 |
17.7 |
50 |
63.3 |
10 |
12.7 |
5 |
6.3 |
11.3 |
0.02 |
Also, the results of the correlation test between tooth decay and food consumption pattern showed that there is a positive and significant correlation between tooth decay and BMI (P = 0.001; r = 0.94), and the frequency of consumption of sweets (P = 0.02; r = 0.84), as well as a significant inverse correlation between tooth decay and the average consumption of milk and dairy products (P = 0.016; r = -0.89) and fruits and vegetables (P = 0.01; r = -0.78) but no significant correlation was observed among other cases with tooth decay.
Table 4. Distribution of the frequency of consumption of sweets, sweet and carbonated drinks, and snacks in the studied children.
|
Frequency of consumption
Abundance of decaying food |
Never |
1-2 times a week |
3-4 times a week |
≥ 5 times a week |
χ² |
P |
||||
|
N |
% |
N |
% |
N |
% |
N |
% |
|||
|
Sweets |
4 |
5.1 |
4 |
51.1 |
28 |
35.4 |
43 |
54.4 |
33.2 |
0.03 |
|
Sweet and carbonated drinks |
14 |
17.7 |
14 |
17.7 |
29 |
37.8 |
22 |
27.8 |
19.7 |
0.06 |
|
Snacks |
21 |
26.5 |
6 |
7.6 |
10 |
12.7 |
42 |
53.2 |
32.3 |
0.055 |
Several factors affect the development of tooth decay. Tooth decay is a known multi-cause disease related to nutrition [17-20]. Considering the importance of oral and dental hygiene in childhood, the role of factors affecting it is also important. Today, special attention has been paid to the relationship between eating habits and obesity with oral health status [17-19]. In this study, the relationship between tooth decay and nutritional status based on body mass index and food intake of children was investigated.
The relationship between childhood obesity and tooth decay is very complex and is related to various factors such as age, sex, race, and family income [8]. The results of studies by Narksawat et al. [17] in urban and rural children of Thailand and Parshnath et al. [8] in India indicated a negative relationship between body mass index and tooth decay. In the present study, a positive and significant correlation was obtained between body mass index and DMFT. It has been suggested that probably an inappropriate eating pattern, especially excessive consumption of foods containing carbohydrates and sugars, exposes children to the risk of caries and being overweight at the same time [4, 5].
The results of the frequency of food consumption showed that the studied children used other main food groups, except for dairy products, fruits, and vegetables. In children with DMFT ≥ 4, the average consumption of milk and dairy products and fruits and vegetables was significantly lower than in other children, which indicates the direct effect of the child's diet on tooth decay. The presence of mineral salts, including calcium and phosphorus, vitamins A and D, as well as protein components in milk and dairy products, play an important role in preventing tooth decay [21, 22]. Calcium strengthens bones and teeth with the help of vitamin D and phosphorus. The lack of these minerals can lead to changes in the structure of teeth and gum tissues and increase the basis for tooth decay. It should be noted that incorrect and insufficient nutrition aggravates these complications in the long term [23, 24].
Regarding the relationship between food intake and tooth decay in children, many studies with different results have been reported. In some studies [25], an inverse relationship between the consumption of milk and dairy products with the condition of the gums and tooth wear was observed. The results of these studies confirm the results of the current research. Similar to the findings of our study, Stewart et al. [26] also reported that the prevalence of caries in children whose main diet was vegetables is lower than in other children. Even though fruits and vegetables contain natural sugar, due to the presence of a lot of water in them, their sugar is diluted, and as a result, they have little decay power. Also, due to the presence of fiber in them when chewing, they neutralize the action of fermenting bacteria and help to clean the teeth. More secretion of saliva when eating fresh fruits and vegetables neutralizes the amount of acid caused by the fermentation of simple carbohydrates, balances the pH of the mouth, and helps to maintain and restore tooth enamel. On the other hand, the presence of vitamins, including vitamins C and A found in many fruits and vegetables, is beneficial for the health of the gums. Sugar and other fermentable carbohydrates such as candy, biscuits, and cookies are also considered one of the most important factors of caries [27, 28].
Studies have shown that repeated consumption of snacks, especially sweet foods during the day with a decrease in the pH of oral saliva is an effective factor in tooth decay. The amount of acid produced by the fermentation of food by oral bacteria depends on the amount of sugar in that material. Especially the relationship between the consumption of food containing sugary substances that have a greater adhesive power on the surface of the teeth [29].
In the present study, a significant correlation was observed between the frequency of consumption of sweets and tooth decay. Similar to the results of the present study, Eronat et al. [30] studied children in Turkey, and Amin et al. Gives. Grenby's study [29] on British students also showed that almost all children consumed cakes, biscuits, and chips. In our study, 43 people (54.4%) of children used snacks such as chocolate sweets and candies more than 5 times a week, of which 21 people (48.8%) had excess underweight and obese, and the DMFT index (DMFT ≥ 4) in this group was significantly higher than other children. The results showed that in children whose parents had secondary and higher education, the average DMFT was lower than other children. Probably, more awareness of educated parents about oral and dental problems and their attention to children's health plays an important role in dental care for children [1-4]. Therefore, the level of education of parents can also be considered as one of the influential factors in the incidence of tooth decay.
Conclusion
The results showed that the frequency of caries index in overweight and obese children was significantly higher than in other children. The results of the frequency of food consumption showed that all children, except for the milk and dairy group, used fruits and vegetables from other food groups. An inverse correlation was observed between tooth decay and the average consumption of milk and dairy products, fruits, and vegetables, and a significant positive correlation was observed between BMI and the frequency of consumption of sweets. In the present study, obesity, consumption of carious snacks, and reduction in consumption of dairy products, fruits, and vegetables have been proposed as risk factors for dental caries in children. Considering the importance of teeth in children's general health, it seems necessary to educate parents and children about following a balanced diet.
Acknowledgments: None
Conflict of interest: None
Financial support: None
Ethics statement: None
