KARIJES RIZIK PROFIL DECE PREDŠKOLSKOG UZRASTA GRADA NIŠA CARIES RISK PROFILE OF PRESCHOOL CHILDREN IN THE CITY OF NIŠ

1 UNIVERZITET U NIŠU, MEDICINSKI FAKULTET, KLINIKA ZA STOMATOLOGIJU, PREVENTIVNA I DEČJA STOMATOLOGIJA, NIŠ, SRBIJA 2 UNIVERZITET U NIŠU, MEDICINSKI FAKULTET, ORALNA MEDICINA I PARODNOTOLOGIJA, NIŠ, SRBIJA 3 UNIVERZITET U NIŠU, MEDICINSKI FAKULTET, KLINIKA ZA STOMATOLOGIJU, ORTOPEDIJA VILICA, NIŠ, SRBIJA 4 UNIVERZITET U NIŠU, MEDICINSKI FAKULTET, STOMATOLOŠKA PROTETIKA, NIŠ, SRBIJA 5 UNIVERZITET U NIŠU, MEDICINSKI FAKULTET, STUDENT DOKTORSKIH STUDIJA, NIŠ, SRBIJA


Introduction
Early childhood caries is defined as the presence of one or more decayed, missing (due to caries) and filled surfaces of primary teeth in children up to 71 months of age, which includes preschool children aged 3 to 6 years 1 . Epidemiological studies indicate a high prevalence of caries in preschool children, which in some countries reaches as much as 85.5% 2 . Current data show that about 30% of children aged 3 in the Republic of Serbia has at least one decayed, missing or filled (dmf) tooth, that the incidence of caries increases with age, and that as many as 89% of children aged 6 has at least one decayed, missing or filled tooth 3 . According to these data, the prevalence of caries in children in the Nišava district is within the national average, i.e. each child in this age group has an average of 2.31 decayed, missing, and/or filled teeth 4 .
In many countries around the world, including the developed ones, caries is still a major social, economic, and health problem 5 . At preschool age, caries is the leading cause of oral pain and tooth loss, with a negative repercussion on the quality of life of children and their families [6][7][8] . Moreover, research has shown that early childhood caries is a significant caries predictor in school-age children 9 .
Therefore, primary caries prevention from the earliest childhood has multiple significance, and its efficacy is, in addition to identifying the subpopulation at risk, conditioned by the knowledge of caries risk factors and caries predictors as a basic prerequisite for developing effective measures and strategies for disease prevention and control 10 .
Due to the multicausal etiology of caries, a large number of variables may be important in the field of caries risk assessment. However, it was found that none of them as a solo factor showed high reliability in the assessment of caries risk and that the prediction of future caries increases with the simultaneous combined application of the variables that have shown importance in the diagnosis of caries risk 11 . In 1997, Bratthall et al. developed Cariogram ® , a computer program for assessing caries risk, whose efficacy was tested for different subject age groups 12 . This program takes into account the interaction between individually assessed caries risk factors which have shown the greatest caries predictive importance: caries experience, associated diseases, dietary composition and frequency of intake, oral hygiene, fluoride bolesti, sastav ishrane i frekventnost unosa hrane, stanje oralne higijene, primena fluorida, brzina protoka i puferski kapacitet pljuvačke, salivarni nivo kariogenih mikroorganizama. Međutim, nedavno su Petsi i sar. 13 i Taqi i sar. 14 sugerisali to da primena ovog komjuterskog programa može biti ograničena u zemljama niskog socioekonomskog statusa, jer zahteva upotrebu skupih salivarnih testova. Stoga su ovi autori testirali primenu redukovanog Cariogram ® modela, kojim salivarni testovi nisu obuhvaćeni i utvrdili da se uz nešto niži prediktivni značaj može koristiti za efikasnu procenu karijes rizik profila dece.
Uzimajući u obzir značaj poznavanja karijes rizik profila dece predškolskog uzrasta za primarnu prevenciju karijesa, cilj ove studije bio jeda se izvrši procena karijes rizik profila dece predškolskog uzrasta na teritoriji grada Niša, primenom redukovanog kompjuterskog Cariogram ® modela.  13 and Taqi et al. 14 have recently suggested that the application of this computer program may be limited in countries of low socioeconomic status, as it requires the use of expensive salivary tests. Therefore, these authors tested the application of a reduced Cariogram ® model which did not include salivary tests and found that it could be used with somewhat lower predictive significance to effectively assess the caries risk profile of children.

Materijal i metode
Considering the importance of the knowledge of the caries risk profile of preschool children for primary caries prevention, this study was aimed at assessing the caries risk profile of preschool children in the City of Niš using a reduced computer Cariogram ® model.

Study design and subjects
To achieve the goals set, a crosssectional study that included preschool children aged 36-48 months was conducted. The study included patients of the Department of Preventive and Paediatric Dentistry of the Dentistry Clinic of the Faculty of Medicine, the University of Niš, Serbia, as well as patients of preschool clinics of the Department of Preventive and Paediatric Dentistry of the Community Health Centre in Niš. The parents of the subjects received all necessary information and gave written consent to the participation of children in this study, whose implementation was approved by decision number 12-14532-2/3 of the Ethics Committee of the Faculty of Medicine, the University of Niš.
The subjects were selected according to the basic criteria: 1) healthy subjects without acute and chronic systemic diseases in personal history; 2) subjects with permanent residence in the City of Niš since birth (average concentration of fluoride in drinking water is ≤0.05 mg/mL); 3) subjects without diagnosed structural defects on the teeth.
The size of the representative sample was determined on the basis of data on the population of children aged 36-48 months, selected according to the described criteria and the prevalence of caries in this age group of children with a confidence level of 5% and a study strength of 80%. The minimal calculated sample size was 249 subjects aged 36-48 months.

Assessment of caries risk profile of subjects
The caries risk profile of the subjects was assessed using the Cariogram ® model. To achieve the set goals, this study used a reduced Cariogram® model described by Taqi et al. 13 , which included seven variables out of the possible ten: caries experience, associated diseases, composition of diet, frequency of food intake, amount of plaque, fluoride use, and clinical assessment. Saliva and bacterial culture tests were excluded from the program.
The collection of data was done by a specialist in Preventive and Paediatric Dentistry. The mothers filled in a questionnaire, created for this study to collect, in addition to basic demographic data, data on (1) the health status of the subjects; (2) the frequency of carbohydrate intake and the number of daily meals (estimated based on food intake in the last three days); (3) fluoride intake through toothpaste and tablets.
The clinical examination of the subjects was performed using a probe and a dental mirror. The condition of dental health was recorded by the "visual-tactile" method following the WHO criteria for epidemiological research 15 , and expressed by the Klein-Palmer's 16 dmf (decayed, missing, filled) system, after which the dmf and dmfs indices were calculated. The assessment of the oral hygiene condition was performed using a simplified oral hygiene index according to Greene-Vermilion 17 (OHI-S), for whose determination the surfaces of six teeth, the representative for the entire dentition, were used. In primary dentition, according to Sowole et al. 18 , the vestibular surfaces of teeth 55, 51, 65, 71, as well as the oral surfaces of teeth 75 and 85 were used to determine the index.
After collection, the data were entered into the computer Cariogram ® program (available at www.mah.se/fakulteter-ochomraden/Odontologiska-fakulteten/Avdelningoch-kansli/Cariologi/Cariogram/). The variable "caries experience" was assessed based on the fact that the average DMF index of preschool children was 2.3 4 . The variable "clinical assessment" was in accordance with the one assessed by the Cariogram ® model, and for all subjects amounted to 1 .
Based on the Cariogram ® -estimated chance of avoiding new carious lesions, caries risk assessment in the studied group of children was performed, following the criteria shown in Table 1.

Statistical data processing
Statistical data processing was done in MS Excel program.
The frequency of caries was expressed by statistical indices (Caries Index of Persons (pci), Caries Index of Teeth (tci)), indices and average values measures (Caries Index Average (aci), the average number of tooth surfaces affected by caries (dmfs)), and indicators of caries structure (dmf structure).
Within descriptive statistics, numerical data were presented by measures of central tendency (mean value) and measures of variability (standard deviation). Attributive features were presented in the form of absolute and relative numbers. The obtained data are shown in tables and graphs.

Results
According to the set criteria, 276 preschool subjects aged 36-48 months, were selected. The basic demographic and clinical characteristics of the subjects are shown in Table 2.
The average Cariogram ® model shows that preschool children have an average of 50% chance of avoiding caries in the future (Graphic 1). The highest percentage of the subjects belongs to the moderate caries risk group, with the largest number of them having between 61-80% chances of avoiding the appearance of a new caries lesion in the future. Thirteen point four percent of the children of the studied age showed a high caries risk (Graphic 2).
The average caries risk profile of the children of the examined age was dominated by the "susceptibility" sector (18%), which referred to the use of fluoride in children of this age, followed by the "bacteria" sector (14%) (referred to dental hygiene) and then the "nutrition" sector (12%) (referred to variables related to nutrition -composition and frequency of food intake).

Discussion
Starting from the importance of the knowledge of the caries risk profile of a subpopulation at risk for primary prevention of caries, the aim of the study was to analyse the caries risk profile of preschool children in the City of Niš.
In the studied group of healthy preschool children in Niš aged 36 to 48 months, a moderate prevalence of caries was registered, with values of the examined parameters of caries prevalence that are generally in accordance with current data 3,4 . However, the study registered an unfavourable DMF structure, with a pronounced dominance of untreated, decayed teeth, which suggests that the preschool age of children in this region should still be considered a high caries risk age.
The study determined that the largest number of examined children showed a moderate caries risk, whereas 13.4% of them fell into the high caries risk group. In the assessed caries risk profile of the children, the most vulnerable sectors were "susceptibility" and "bacteria", which referred to the use of fluoride in children of this age and their oral hygiene.
It is widely recognized that fluorides exhibit the strongest cariostatic effect and that their controlled application is still the strongest caries preventive measure. The fluoride application program adopted by the European Academy of Paediatric Dentistry in 2000 and revised in 2009 and 2019 19 gives preference to the exogenous fluoride application, which is considered quite sufficient in areas where the concentration of fluoride in drinking water is optimal, i.e. above 0.3 mgF/L. Since this is not the case in Niš, in addition to toothpaste, the use of fluoride in the form of supplements is required. Based on the results of this study, the most common source of fluoride in children of this age is toothpaste, whereas supplements in the form of tablets are occasionally used or have been used by 10% of the children. About 12% of the subjects does not use fluoride in any form. Therefore, it can be considered that the exposure of teeth to fluoride is insufficient at this age and that, when developing caries preventive measures and strategies, it is desirable to consider the implementation of programs for fluoride application according to the proposed protocol of the European Academy of Paediatric Dentistry. Stoga, programom zdravstvenog vaspitanja treba, pre svega, obuhvatiti roditelje, budući da je briga o zdravlju zuba dece ovog uzrasta njihov zadatak. Međutim, treba napomenuti da ovaj program ne treba zasnivati na samom pružanju informacija, jer to obično daje kratkoročne rezultate 20 , te je neophodna i stalna motivacija i remotivacija, sa ciljem da se zdrave navike prihvate i prenesu na decu, što je često složen i dugotrajan proces.
The study determined high values of plaque index, which suggests the need for a more detailed analysis of the main criteria for assessing the maintenance of oral hygiene -frequency, regularity, frequency and technique of toothbrushing. Therefore, the health education program should primarily include parents, given that taking care of the dental health of their children at this age is their task. However, it should be noted that this program should not be based solely on the provision of information as it usually gives short-term results 20 , and that constant motivation and remotivation are necessary to adopt healthy habits and transmit them to children, which is often a complex and time-consuming process.
Even though diet is one of the primary caries factors, studies have shown that as a caries risk factor it is not of great importance, i.e. that its role is often masked by the use of fluoride and the frequency of oral hygiene.
The reduced Cariogram ® program shows that preschool children in Niš have an average of 50% chance of avoiding the appearance of a new caries lesion in the future. This result suggests that every other child may have an increased incidence of caries over one year. With such a trend, in this group of children in a year, it may be expected there will be a statistically significant increase in the incidence of caries, which can be considered a realistic outcome, as suggested by everyday clinical pedontological experience. Undoubtedly, this result also suggests the need for intensive work in the field of primary prevention of caries in children of this age to avoid all negative consequences that caries and its complications bring at this age. This primarily refers to pain, dentogenic infections and premature tooth loss, which leads to disruption of all functions of the entire masticatory apparatus, and disruption of social interaction of children, which, along with the economic component, significantly contributes to the impaired quality of life not only of children but of their entire families as well. Also, premature loss of one or more teeth impairs further development of the orofacial region. To avoid these negative consequences, one of the solutions could be prosthetic rehabilitation of primary teeth and making space maintainers, which can be quite complex at this age and unacceptable for the youngest patients. All this confirms the importance of primary prevention of caries from the earliest childhood, which is why it represents a basic step in the clinical approach to caries.

Conclusion
The registered moderate prevalence of caries in the examined group of children indicates that this developmental period can be regarded as a high caries risk period, and should be particularly considered in the field of primary dental health care of children. Based on the results of the study, insufficient exposure of teeth to fluoride and inadequate oral hygiene may be considered the most significant caries risk factors, which should be taken into account when choosing measures and strategies for disease prevention and control. Furthermore, it is necessary to reconsider the time of diagnostic examinations to reduce the prevalence of caries and its negative consequences at this age to a minimum.

Conflicts of Interest statement
The authors declare no conflicts of interest.