Differences in Caries Status and Risk Factors among Privileged and Unprivileged Children in Colombia.

OBJECTIVE: The objective of this study was to compare the ICDAS-II caries status and caries-related factors among children from rural and urban schools in Pasto, Colombia.
MATERIALS AND METHODS: The study included 120 children (4 - 6 year- old children) from rural (privileged) and urban (unprivileged) schools. Caries was evaluated using the ICDAS-II criteria. A survey about the factors related to the presence of caries was applied. Chi-square and Fisher's tests were used to assess the differences in each study variable between the two groups. A Mann-Whitney U test was used to compare the number of teeth, per ICDAS-II category, between the groups. Negative binomial regression was used to estimate the percentage change in the mean number of teeth, per ICDAS-II category, among the rural and urban students.
RESULTS: Significant differences were found between the rural and urban students for the ICDAS-II 0 and 3-6 categories (p<0.001). The mean number of teeth with moderate-to-severe caries status increased 233% in children from the rural school compared to those attending the urban school (p=0.0). Toothbrushing frequency (p=0.006), cariogenic diet, time elapsed from last dental visit, socioeconomic status, and type of health regime (p<0.001) were among the significant factors related to the rural and urban schools.
CONCLUSIONS: This was the first study to compare ICDAS-II caries status between rural and urban students in Colombia. A worse caries status was found in rural students. This study identified the socioeconomic and clinical factors to guide specific interventions for rural children by modifying the available oral health promotion and disease prevention programs.

Introduction

Dental caries is considered to be one of the most prevalent pathologies in the history of oral morbidity worldwide (). Caries can cause functional, physical and esthetic deterioration, which can affect both the general health and quality of life of children (). In Colombia, the prevalence of caries was 52.20% and 52.38% (in 5 year- old children) in primary and mixed dentition, respectively (). At a local level, in students from Genoy (Pasto, Colombia) a 2008 study (published in 2012) showed that the dmft was 5.16 in 5 year- old children and the caries prevalence was 88% (). In another study of the Genoy population, the prevalence of caries was similar: 88% (). The efforts made by the government were not sufficient; oral diseases are still the second most common cause of morbidity in the Colombian population and the population of Genoy, and caries is one of the most prevalent pathologies (). Dental caries is a multifactorial disease related to intraoral bacteria, oral hygiene (), and good dietary practices (, ). Oral health is also affected by social, economic, environmental, and geographic factors (, ). In rural areas, it is more common to find higher levels of poverty and lower educational and socioeconomic levels than in urban areas (). In Colombia, according to the ENSAB-IV, the prevalence of dental caries in rural areas, as measured by the DMFT/dmft index, was lower in primary and mixed dentition (32.33%), while in urban areas the prevalence was higher for primary (46.41%) and mixed (57.88%) dentition. On the other hand, the prevalence of caries, as measured by a modified version of the DMFT that included the ICDAS (International Caries Detection and Assessment System) criteria (D(2-6 ICDAS)MFT), was higher in the rural areas for three kinds of dentition (69.59% in primary, 93.59% mixed and 82.59% in permanent dentition) (). These data show that DMFT/dmft underestimated the diagnosed cases of caries.

The infant population, especially in rural areas, is vulnerable to the presence of caries, which makes it necessary to establish diagnostic baselines that allow the identification of caries lesions in a timely manner. The ICDAS-II system was developed as a visual method to detect caries in its early phase, determine its severity and measure its level of activity; it is utilized in the clinical practice, research and development of public oral health programs (-). The efficacy of the ICDAS-II has been compared to transillumination, fluorescence, and radiographic methods (-). The ICDAS-II consists of a two-digit code that is assigned to each tooth. The first digit (0-9) refers to dental condition (intact, partially sealed, fully sealed, etc.) (). The second digit refers to the categories that establish the caries status (). The objective of this study was to compare the caries status, measured by the ICDAS-II criteria, and the factors related to the caries development among children from rural and urban schools in Pasto (Colombia). This study will allow for the reorientation of public oral health programs specific to the study population, according to their sociodemographic conditions. This will cause a major reduction in the prevalence of caries in these rural populations ().

Materials and methods

This was an observational analytical cross-sectional study. A convenience sampling among registered students during 2014 was performed in 4 rural schools in the town of Genoy and an urban school; all the educational institutions were in Pasto city, Nariño (Colombia). The rural schools were public, and the urban school was private. Four to five- year-old children (n=120) with primary dentition were selected. We excluded children with systemic diseases and dental patients with severe conditions. From a total of 64 children registered in rural schools, 60 children (unprivileged) were included and their parents signed a voluntary informed consent; this determined the number of children selected in the urban school. There were 72 registered children, 4 to 6 years olds, in the urban school and 60 (privileged) were randomly selected for the study. The parents of the children from the urban school also signed a voluntary informed consent. This research was ethically conducted based on the Declaration of Helsinki and the Bioethics Subcommittee of the Universidad Cooperativa de Colombia (UCC) Pasto approved the study (Ethics Committee approval number: 04-2014).

The ICDAS-II criteria were used to classify each tooth according to the caries status (). The diagnosis was established using a calibrated ICDAS-II pediatric dentist. During the procedure, the pediatric dentist worked on clean, dry teeth using adequate light. The data were registered using the odontogram formats from the UCC Pasto. A total of 22 variables were analyzed. The variables which were analyzed included the number of healthy teeth (ICDAS-II 0), the number of teeth in the initial stage of caries (ICDAS-II 1-2), and the number of teeth in the moderate-severe stages of caries (ICDAS-II 3-6). Ten important clinical and dental health variables were measured by a second dentist or taken from a survey of the cariogenic diet (UCC format). The variables were as follows: time since the last dental visit; use of a toothbrush, dental floss, and mouthwash; toothbrushing frequency; bleeding gums during toothbrushing; bacterial plaque; cariogenic diet; application of fluoride, and dmft. The dmft was classified as very low (0 – 1.1), low (1.2 – 2.6), moderate (2.7 – 4.4), high (4.5 – 6.5), and very high (≥ 6.6). Eleven sociodemographic variables were measured using a survey answered by the parents of the children and created by the principal investigator, including: gender, age, socioeconomic status, educational level, access to electricity, sewer systems, television, telephone, internet, cellphone, and type of heath service. A pilot test was performed on 28 parents to validate the sociodemographic survey; an Alfa Cronbach test was used in which a value near one represented high validity and consistency. The pilot test Alfa Cronbach value was 0.884.

Statistical analysis

The clinical and sociodemographic variables were summarized per group (rural or urban) using contingency tables with absolute and relative frequencies. To summarize the dependent variables, we used measures of central tendency and dispersion. The Pearson's chi-square test was used to identify the significant differences for each clinical or sociodemographic variable between the groups. When the expected values of more than 20% of cells in a contingency table were lower than 5, the Fisher’s exact test was applied. The comparison of the number of teeth per caries category, according to the ICDAS-II criteria (healthy, initial, and moderate-severe), among children from the rural and urban schools was performed using the Mann–Whitney U test. Simple and multiple negative binomial regressions were used to estimate the percentage change in the mean of healthy teeth (ICDAS-II 0) and teeth in the moderate-severe category (ICDAS-II 3-6) between the rural and urban students. The multiple regression was used to age-adjust for the estimated percentage change. The significant p-value threshold was set at 0.05. The analyses were performed using R v.3.3.3 and the libraries “tableone” and “MASS” ().

Results

Analysis of the caries status according to ICDAS-II criteria

The ICDAS-II moderate and severe categories were grouped into one category called the moderate-severe category due to the small sample size per category. Therefore, the Mann–Whitney U test was performed independently for three ICDAS-II categories: healthy teeth (ICDAS-II 0), initial stage of caries (ICDAS-II 1-2), and moderate-severe caries (ICDAS-II 3-6), comparing the rural and urban groups. Table 1 shows the results of these analyses. Significant differences were found between the rural and urban students with respect to the healthy and moderate-severe (p < 0.001) categories. In both schools, most of the teeth were healthy (n = 20). The median number of healthy teeth was 16 in the rural school (mean = 14.9 ± 4.0) and 19 for the urban school (mean = 18.2 ± 2.0). In the moderate-severe category, 15 teeth in the rural school compared to 5 in the urban school were classified with ICDAS-II codes 3 to 6. The median of moderate-severe teeth was 3.5 (mean = 4 ± 3.0) in the rural school and 0 (mean = 1.2 ± 1.5) in the urban school. The estimated percentage change in the number of teeth in the healthy or moderate-severe categories among the rural and urban students was calculated. Figure 1 shows the results of the negative binomial regression adjusting for age or not, to identify the possible effect of age on the differences observed between the groups. Before and after adjustment for age, the median number of teeth in the moderate-severe category increased significantly by 233% in the children from the rural area compared to children in the urban area. The mean number of healthy teeth was significantly lower (16%) in the rural students compared to the urban students.

Table 1

Frequency distribution table of variables important to clinical practice and to comparison of dental health between rural and urban students.

Variable	Level	Rural school(n=60)	Urban school (n=60)	p
		Mean (SD)	Mean (SD)
Healthy teeth (ICDAS-II 0)		14.9 (4)	18.2 (2.0)	<0.001*
Teeth in initial stage of caries (ICDAS-II 1 – 2)		0.3 (1)	0.2 (0.5)	0,737*
Teeth in moderate-severe stage of caries (ICDAS-II 3 – 6)		4.0 (3)	1.2 (1.5)	<0.001*
		n (%)	n (%)
Time since the last dental visit	1 month	12 (20.0)	6 (10.0)	<0.001
	2 months	20 (33.3)	6 (10.0)
	3 months	18 (30.0)	20 (33.3)
	> 3 months	10 (16.7)	28 (46.7)
Use of toothbrush	Yes	57 (95.0)	60 (100.0)	0.242
	No	3 (5.0)	0 (0.0)
Use of dental floss	Yes	18 (30.0)	23 (38.3)	0.441
	No	42 (70.0)	37 (61.7)
Use of mouthwash	Yes	9 (15.0)	33 (55.0)	<0.001
	No	51 (85.0)	27 (45.0)
Toothbrushing frequency (times/day)	One	7 (11.7)	2 (3.3)	0.006
	Two	30 (50.0)	18 (30.0)
	≥ 3	23 (38.3)	40 (66.7)
Bleeding gums during toothbrushing	Yes	7 (11.7)	21 (35.0)	0.005
	No	53 (88.3)	39 (65.0)
Bacterial plaque	Yes	59 (98.3)	42 (70.0)	<0.001
	No	1 (1.7)	18 (30.0)
dmft (%)	Very low	3 (5.0)	27 (45.0)	<0.001
	Low	4 (6.7)	7 (11.7)
	Moderate	8 (13.3)	9 (15.0)
	High	14 (23.3)	10 (16.7)
	Very high	31 (51.7)	7 (11.7)
Cariogenic diet	High	57 (95.0)	23 (38.3)	<0.001
	Average	3 (5.0)	31 (51.7)
	Low	0 (0.0)	6 (10.0)
Fluoride application	Yes	3 (5.0)	35 (58.3)	<0.001
	No	57 (95.0)	25 (41.7)

*Mann-Whitney U test. The differences between category variables were evaluated using chi-square or Fisher’s tests, as appropriate. Values lower than 0.05 are shown in bold. SD: standard deviation.

Figure 1

The estimated percentage change in the number of teeth in the healthy or moderate-severe categories among the rural and urban students (results of the negative binomial regression for the raw and adjusted for age estimates). Age did not have a significant effect on the percentage change.

Table 1 shows the results of comparing variables important for the clinical practice and dental health of children from the rural and urban schools. The significant variables in the groups (p < 0.001) were time since the last dental visit, use of mouthwash, presence of bacterial plaque, cariogenic diet, fluoride application, and dmft (%). The toothbrushing frequency and presence of bleeding gums during toothbrushing (p < 0.05) were also significant. In contrast to the urban school, in the rural school, the dmft was considered high and the diet was highly cariogenic (Table 1). Toothbrushing 3 or more times per day and the use of mouthwash were less frequent in the rural area. Table 2 summarizes the results of the bivariate analysis between the rural and urban schools. There were no significant differences in gender between the schools. Significant differences (p < 0.001) were found for age, socioeconomic status, educational level, access to sewer systems, telephone, and internet, and type of health regime. The most frequent socioeconomic status among the 5 statuses was 1 (the lowest) in the rural schools and 3 and 4 in the urban school. All children in the rural schools belonged to the subsidized health regime, compared to 5% of the urban students. In terms of access to public services, the rural area had significantly less access to sewer systems (68.3%) compared to the urban area (100%). The access to internet was limited in the rural area (16.7%) compared to the urban area (88.3%). The use of cellphones was similar between the two areas.

Table 2

Distribution of the sociodemographic variables among privileged and unprivileged children.

Variable	Level	Rural school (%)	Urban school (%)	p
n		60	60
Gender	Female	24 (40.0)	33 (55.0)	0.144
	Male	36 (60.0)	27 (45.0)
Age	4	0 (0.0)	11 (18.3)	<0.001
	5	25 (41.7)	12 (20.0)
	6	35 (58.3)	37 (61.7)
Socioeconomic status	1	57 (95.0)	0 (0.0)	<0.001
	2	3 (5.0)	1 (1.7)
	3	0 (0.0)	40 (66.7)
	4	0 (0.0)	19 (31.7)
Educational level	Preschool	8 (13.3)	22 (36.7)	<0.001
	Kindergarten	33 (55.0)	9 (15.0)
	First grade	19 (31.7)	29 (48.3)
Electricity	Yes	59 (98.3)	60 (100.0)	1
	No	1 (1.7)	0 (0.0)
Sewer systems	Yes	41 (68.3)	60 (100.0)	<0.001
	No	19 (31.7)	0 (0.0)
Television	Yes	56 (93.3)	59 (98.3)	0.361
	No	4 (6.7)	1 (1.7)
Telephone	Yes	10 (16.7)	48 (80.0)	<0.001
	No	50 (83.3)	12 (20.0)
Internet	Yes	10 (16.7)	53 (88.3)	<0.001
	No	50 (83.3)	7 (11.7)
Cellphone	Yes	52 (86.7)	54 (90.0)	0.776
	No	8 (13.3)	6 (10.0)
Health regime	Subsidized	60 (100.0)	3 (5.0)	<0.001
	Contributory	0 (0.0)	57 (95.0)

The differences between category variables were evaluated using chi-square or Fisher’s tests as appropriate. Values lower than 0.05 are shown in bold. SD: standard deviation.

Discussion

The present study compared the caries status according to the ICDAS-II criteria and caries-related clinical and sociodemographic factors for children from rural and urban schools in Pasto, Colombia. Several studies have evaluated the oral health status of the general population and have compared the prevalence of caries in rural and urban areas based on the DMFT/dmft indices (, , ). In the present study, we evaluated the history of caries using both methods, ICDAS-II and dmft, and emphasized the ICDAS-II results. In the population studied from Genoy (rural), this is the first time that the caries status of children has been evaluated using the ICDAS-II system, which will allow for a follow-up of the evolution of the caries in those children. One other study evaluated the caries status using the ICDAS-II criteria in rural and urban populations (). This French study included 6-year-old children from rural and urban schools and found significant differences between the two zones for the ICDAS-II 1-2 codes. Using the ICDAS-II method, 39% of the children were identified as free of caries, while using the WHO basic method, 67.2% of the children were identified as free of caries; these results indicate the better precision of the ICDAS-II system to measure carious lesions from the non-cavitated stages ().

In the present study, the most frequent dmft category was “very high” in rural students and “very low” in urban students; this is concordant to the ICDAS-II results. Other studies performed in Genoy measured the history of caries using the dmft method (, ). A mean dmft of 5.16 (high) in 5-year-old students and 4.58 (high) in 12-year-old students were reported (). The results for the 5-year-old students are close to our results in which a “very high” level of caries was predominant. It is important to consider that the present study included 4- to 6-year-old children and could have an impact on the mean dmft measurement. A study carried out in Popayan (province of Cauca), a southern Colombian city in the province next to Nariño, where Genoy is located, found a 96% history of caries in 12-year-old children and a dmft of 3.02 (); these values were similar to the ones found in Genoy.

In general, the caries status was worse in the rural students compared to the urban students in the present study, which was comparable to results reported by Cabrera et al. (), Fernandez-Gonzalez et al. () in Chile and Ribeiro de Campos Mello et al. () in Brazil. Worldwide, the studies showed contradictions for the prevalence of caries in urban and rural areas depending on the country. In the United States, China, Sweden, Burkina Faso and Senegal (), the prevalence of caries in children and adolescents was higher in the urban areas than in the rural areas. However, in other studies the highest prevalence of caries occurred in rural areas compared to urban areas (India, Russia and Poland) (-). These contradictory results can be explained in part because in very isolated rural areas, although there is less access to oral health services, the unfavorable socioeconomic conditions limit the access to cariogenic food, which can be easily found in urban zones (). These contradictory studies have shown that the differences in oral health found in rural and urban areas differ between developed and developing countries; furthermore, they differ among regions inside the same country or between countries with the same economic levels. It is recommended to conduct a follow-up investigation and intervene in populations at a small regional scale, considering the socioeconomic conditions and behavioral aspects of each region that create barriers to maintaining good oral health ().

Comparison of variables important for clinical practice and dental health

Nine variables important for clinical practice and dental health were significantly different in rural students compared to urban students. Children from the rural schools had more bacterial plaque and bleeding during toothbrushing; in summary, they showed worse oral health. Other important dental health variables agree with the low quality of oral health observed in the rural schools from Genoy. The presence of bacterial plaque and a cariogenic diet was higher in the rural students; toothbrushing, the use of mouthwash and application of fluoride were less frequent in rural students. A cariogenic diet, along with poor oral health care, is considered a risk factor for caries in children and adults (, , , ).

Comparison of sociodemographic variables

The utilization of cellphones was similar in the rural and urban areas because, in Colombia, there is access to low cost low-end and prepaid cellphones. It is important to consider the different technologies available to the population when health promotion and disease prevention programs are designed. For example, in the homes of children from the rural and the urban schools, there is approximately 90% access to cellphones and television; thus, these media channels can be used for dissemination of intervention programs using cellphone applications or television commercials. Most rural students belonged to the lowest socioeconomic status, which was 1 in Colombia. In addition, the rural school was public, and the urban school was private. In a study by Do et al. () (2015) completed in Australia, there was a higher weighted prevalence of caries in children from 5 to 8 years old from public schools (51.7%) than private (37.8%) or catholic schools (38.4%). There was also a higher weighted prevalence of caries from families with low incomes (54.4%) compared to families of mid (44.0%) to high (37.8%) incomes (). The differences in the socioeconomic status and the kind of school, private or public, were related to the type of health regime to which the children were affiliated in both the rural and urban area; in the present study, all the rural students belonged to the subsidized health regime and most children in the urban school belonged to the contributory health regime. The kind of regime with which a person is affiliated has an impact on their health, including their oral health (). The health system in Colombia is inequitable; the coverage is not universal, and there are differences in the health plans and the system’s expenditure according to the population’s income (). The differences between the contributory and subsidized regimes create limitations to accessing preventive services and timely oral health attention in the rural areas (), because in the contributory regime, the time to get health attention is longer. Additionally, the request and authorization of appointments, medications and treatments takes longer, causing some citizens to drop their right to access health care in many cases. For example, in Colombia, in 2010, 65% of the people from rural areas consulted about their health in a medical center compared to 73% of people in the urban areas (). In addition, in the rural areas of Colombia, people cannot afford medical treatments not covered by their health regimes, or if the treatments are available only in urban zones (which is common), they cannot afford transportation to visit a medical center outside their towns ().

This study had limitations; the number of students in the rural schools was small because the population of this rural area with access to education was also small. There were difficulties collecting the voluntary informed consent due to some parents being unable to attend the researchers’ visit to the school to collect the documents. When possible, the parents were visited at home to get the signed voluntary informed consent. There were no 4-year-old children registered at the rural schools; for this reason, there was an age difference between the rural and urban groups. Nonetheless, the differences in age did not affect the results, as shown in .

Conclusion

The present study found differences in the caries status between the children from rural and urban schools in Pasto (Colombia) using the ICDAS-II criteria and the dmft index. This study was the first to evaluate caries using ICDAS-II criteria in these populations. The application of the ICDAS-II system to measure the caries status in this study will allow the creation of actions to protect healthy dental surfaces, to avoid the development of caries in active or inactive lesions and to detect children at risk of worsening their oral condition. Sixteen out of 22 variables analyzed were significantly different in children from the rural and urban schools. Like other studies that evaluated the caries status of rural populations, we found that toothbrushing, a cariogenic diet, time since the last dental visit; socioeconomic status and health regime were related to caries severity. The significantly different variables between the rural and urban group could explain in part the caries levels observed in rural children, and thus, which aspects of oral health and sociodemographic parameters are to be used for interventions in these populations through the implementation of specific oral health promotion and disease prevention programs to reduce the high caries indices observed in this rural zone.