Dental Caries Experience and Associated Oral Health Determinants of 5-6 Year Old Schoolchildren in Kandy District, Central Province of Sri Lanka

Introduction

Over the past two decades the incidence and prevalence of dental caries among children have declined in industrialized countries, while developing countries have experienced an increasing trend [1, 2]. Therefore, dental caries has become a significant public health problem among children especially in developing countries like Sri Lanka. However, dental caries is a disease of multifactorial etiology which can be prevented using established, evidence-based preventive methods such as fluoride applications, fluoride mouth rinsing, diet modifications and good oral hygienic practices. In fact, the WHO oral health report-2003 [1] noted that the prevalence and incidence of dental caries can be controlled by the joint action of the community, professionals and individuals.

National Oral Health Survey (NOHS) of Sri Lanka in 2003 [3] which traditionally assess the oral health status and treatment needs of Sri Lankan population, reported that mean decayed, missing, and filled teeth (dmft – for deciduous teeth) among the 5 year old children is at a moderate level of 3.51 consisting of 3.26 mean number of decayed teeth (d), 0.12 mean number of missing teeth (m) and 0.13 mean number of filled teeth (f). Furthermore, the prevalence of dental caries in the 5 year old group was reported as 65.31% and 2.21% for deciduous and permanent dentition, respectively. In addition, it has been reported that the prevalence of dental caries varies in different regions of Sri Lanka. For example, the prevalences of dental caries in Galle (southern province), Kandy (central province) and Kalutara (western province) for the 5 year age group were reported as 74.2%, 67.5% and 77.5% respectively. Further, the fluoride levels in water bases have shown a great diversity from less than 0.05ppm to 5ppm [4] in different parts of Sri Lanka. From the published data on NOHS, the prevalence of dental caries in different geographical regions emphasizes the fact that the caries level and water fluoride concentration in water are interrelated in different regions of the country. For example, 14 year old children in Colombo city where levels of fluoride in communal water supply systems was 0.1- 0.5ppm have shown moderate caries level as 3.2 in DMFT and 4.3 in DMFS [5] for permanent teeth. A study conducted to assess caries and fluoride levels in drinking water and their association in children aged 14 living in Uda Walawe; an area with high concentration of fluoride in drinking water, showed that both the caries prevalence and the mean caries experience were significantly lower as DMFS (0.25 + 0.7) for diffuse enamel opacities, and DMFS (1.1 + 1.7) for severe form of enamel opacities [6]. Further they showed that caries prevalence varied between 18- 25% whilst the mean DMFT and DMFS values ranged from 0.29-0.54 and 0.45-0.67 respectively [7]. Further it is noteworthy that only 14.7% of the Sri Lankan population received the desired level of fluoride concentration around 1mg/liter through natural drinking water supplies and the majority of the population is unaware of this fact [8].

Lack of studies on caries prevalence and contributory factors in different age groups in different regions of Sri Lanka emphasize the necessity of further studies in this milieu. This study was undertaken to assess the prevalence and severity of dental caries and the effectiveness of socio- behavioral factors in caries reduction in 5–6 year old school children in Kandy district of Sri Lanka where the naturally occurring water borne fluoride level is low.

Results

Out of the 410 schoolchildren who completed the study and at mean age of 67.3 months (5 years and 7.3 months), 224 were boys and 186 were girls representing

54.63% and 45.37% of the study sample respectively. Table 2 shows their caries experience according to the sex and to the total sample.

Out of the total sample, 32% of the children were caries-free and 68% were caries active. The index for decayed, missing and filled teeth for tooth surfaces (dmfs) was high as 7.2 (±1.1) (Table 2). The mean dmft index of the children was 3.5 (±0.4), and the mean dmfs index was 6.8 (± 0.8) while mean DMFT and DMFS indices were 0.02 (±0.01) and 0.02 (±0.01) respectively (Figure 1). Although, the dmft and dmfs indices levels of boys and girls are not statistically significant in this sample, the boys had higher dmft and dmfs than girls.

The decayed, filled and missed components of dmft comprised of 76.42%, 10.61% and 12.97%, respectively (Table 4), which were not statistically significant between boys and girls. The oral health care level of the population was assessed by means of Care Index and it was 10.61% (Table 3). According to the chi-square analysis on parent socio-demographics, children who used fluoride toothpaste showed lower incidence of caries than others, (OR=0.24, p<0.05) emphasizing that fluoride toothpaste has a positive impact on prevention of dental caries in primary schoolchildren (Table 4).

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*Number (%), NS: not significant © Grade 10 Final Examination/ Selection Exam for the Advanced level studies dmft1: the model was divided into 2 groups as a cut-off by caries free or not. dmft2: the model was divided into 2 groups as a cut-off point by median (50th percentile of children with number of dmft). The adapted scoring method was explained in the materials and methods. Table 4:** Difference in the determinants of oral health and deciduous dental caries.

were not significantly associated with dmft of the children (Table 5).

Discussion

According to the results of this study, the prevalence of dental caries among children at mean age of 67.3 months (5 years and 7.3months) in Kandy District is 68% and it is in line with the reported prevalence for Ragama area in Gampaha district [10]. It is also similar to that of NOHS of Sri Lanka in 2003 [3, 11] in which the prevalence of 5 year age group was 65.31% after seven years. Therefore, Sri Lanka might belongs to the group that did not achieve the goal set by WHO and the FDI (International Dental Federation) in 1981, with focused effort on 50% caries free 5-6 year old children by the year of 2000 [12]. Further, when comparing the dmft of our study of 3.5±0 with the NOHS of Sri Lanka in 2003 [3] where it was 2.21 and with the study of Ragama where it is 1.41 [10] pointed out the high level of caries in our sample. These results indicate continuing moderate level of dental caries in the study area (Kandy, Central province) according to the WHO guidelines [9] in caries levels.

The high proportion of restored teeth (Care index – 10.6%) reported in this study is consistent with the findings of other developing countries [13, 14, 15] and comparable with the care index of the United Kingdom which is 12% across the country [16]. In contrast to our finding the reported CI was 4.72 for preschool children living in Ragama area in Gampaha district [10]. Our result indicates the high perception of treatment need with improvement of oral health care facilities both in the public and private sectors in the study area. Further it highlights the inadequacy of preventive programmes in Kandy District. It is interesting to note that this is inspite of the routine dental care offered to all public schoolchildren in Sri Lanka [3]. A study conducted in New South Wales in Australia has reported a mean dmft score of 1.5 where there oral health programmes which consist of oral health education, risk assessment and clinical care for preschool children [17].

Therefore, we suggest implementing oral health education, risk assessment and clinical care at preschool level to change the symptom-oriented dental treatment seeking pattern to prevention-oriented routine dental care seeking patterns in Sri Lanka. Since Sri Lanka has very effective immunization programmes, preventive dental care clinics may be effortlessly organized in parallel with them. As shown in the Table 4, the only oral health behavioral factor of 5-6 year old children which has a significant effect on the dental caries experience is the use of fluoridated tooth paste. A policy statement of World Dental Federation (FDI) has stated “fluoride tooth paste remains the most widespread and significant vehicle for fluoride used in prevention of tooth decay. Its effectiveness has been confirmed since the 1950’s in over one hundred clinical trials in children, adults and the elderly”. Further fluoride toothpaste is safe to use irrespective of low, normal or high exposure to fluoride from other sources [18, 19].

A Limitation of our study is lack of data on the quality of the tooth paste fluoride content, extent of brushing behavior, time spend for a single brushing process, frequency of tooth brushing and quality of tooth brushing. However, these factors may also affect the efficacy of tooth brushing with fluoride toothpastes. Therefore, further studies are warranted to elucidate the use of fluoride toothpaste in reduction of dental caries in our population.

Conclusion

According to the results of this study, prevalence of dental caries among 5-6 year old children in Kandy district is relatively high (68.8%) with approximately 90% (Care Index of 10.61%) of them having untreated caries. High dmft level of 3.5±0 in the study highlights the urgent need of interventional programmes aiming the improvement of oral hygiene among the children of this age group in Kandy District. Further, our results show that brushing teeth with fluoridated tooth paste is an important factor that reduces dmft of this population.