Index of orthodontic treatment need in children from the Niš Region Indeks potrebe za ortodontskim le enjem kod dece niškog regiona

Background/Aim. The Index of Orthodontic Treatment Need (IOTN) is a scoring system for malocclusion that consists of the two independent components: Denal Health Component (DHC) and Aesthetic Component (AC). IOTNs are usually used in the countries with dental healthcare financed by the government through the national healthcare system or healthcare insurance. The aim of the study was to determine IOTN in primary school children from the town of Niš and to asses percent of children with any kind of orthodontic treatment. Methods. The study involved 301 school children, 11–14 (12.4 ± 1.1) years old. The IOTN was used by the two examiners in order to evaluate the treatment need. Results. The results of the study showed that 111 (37%) out of 301 examined children had orthodonic treatment (33.33% boys and 66.67% girls) and they were excluded from the study. Out of final sample of 190 school children, considering DHC of the IOTN, 27.4% of the children showed great (grades 4–5), 41.0% moderate (grade 3) and 31.6% slight or no treatment need (grade 1–2). Considering IOTN AC, 15.3% of the children showed great (grade 8–10), 24.3 % moderate (grade 5–7) and 60.4% slight or no treatment need (grade 1–4). Conclusion. The need for orthodontic treatment in school children in the town of Niš, Serbia, is similar to the need in most European countries, despite the fact that the number of children orthodontically treated is much higher compared to most of European countries.


Introduction
In the Republic of Serbia, Healthcare Fund provides free mobile appliances for orthodontic treatment for children under 18.Orthodontic treatment with fixed appliances will be charged depending on the institution in which the treatment is carried out.In the City of Niš, in public institutions, generally, there are waiting lists for orthodontic treatment with mobile appliances.Waiting time for the treatment is from two to three months.
The orthodontic treatment is not obligatory and it depends on personal desires of children and their parents.Thus, educating parents and children in this sense even in primary schools, would certainly contribute to rising the awareness among parents and children about the existing orthodontic irregularities.It would influence the increment of the number of patients who request orthodontic treatment.Assessment of the severity of malocclusion and estimating the need for treatment is not always easy and depends on many factors: age, gender, dentition, knowledge, and experience of the orthodontist, but of course also on the financial situation of patients 1 .
Many studies are dealing with the assessment of the need of orthodontic treatment by patients and orthodontists 2-6 .There is a significant difference in the assessment of patients and specialists in orthopedics of jaws, except when it comes to very severe forms of irregularities.
The first quantitative method for the assessment of malocclusion was developed by Massler and Frankel in 1951 7 .Since then a large number of occlusal indexes was developed.Several contemporary orthodontics methods are used for assessing the severity of malocclusion, such as: Index of Orthodontic Treatment Need (IOTN) 4 , Peer Assessment Rating Index (PAR) 8 and the Index of Complexity, Outcome and Need (ICON) 9 .The IOTN and ICON are most commonly used.The results of the measurement needs for treatment obtained by these methods in certain ethnic groups largely coincide 10 .The IOTN is due to its simplicity more frequently used especially among researchers from the Middle East [11][12][13][14][15] .
The IOTN is a scoring system for malocclusion, developed by Brook and Shaw 4 in 1989.It consists of the two independent components.The Dental Health Component (DHC) is a five-grade index that records the dental health need for orthodontic treatment.The Aesthetic Component (AC) records the aesthetic need for orthodontic treatment using a ten-grade standardized ranking scale of colored photographs showing different levels of dental attractiveness.
These indexes are usually used in the countries with dental healthcare financed by the government through the national healthcare system or healthcare insurance (Denmark, Finland, Norway, and Great Britain).The leading idea is to take care of patients with severe orthodontic anomalies first and to limit the free of charge orthodontic services to severe cases of malocclusions.This can considerably narrow the waiting list 3 .
Up to now, in the city of Niš there were no studies on the IOTN.The aim of this study was to determine the IOTN among children from the city of Niš aged 11-14 and to find the percentage of children with the history of orthodontic treatment.The results would help determine the facts about the prevalence of malocclusion and the efficiency of the existing healthcare services.

Methods
The study was approved by the Ethical Committee of the Faculty of Medicine, University of Niš, Serbia.With the help of schoolteachers, families of the examined children were contacted to obtain authorisation.
We examined 301 children, from 4 primary schools in Niš (139 boys and 162 girls).Their average age was 12.4 ± 1.1 years.A group of 111 children of the initial sample was excluded from the study because of a previous or current orthodontic treatment.The final sample included 190 school children, 102 boys and 88 girls.Their average age (± standard deviation) was 12.28 ± 1 years.The sample was chosen in order to give us reliable data for school children population from Niš.
The two orthodontists were collecting data.Before starting investigation, the necessary calibrations using plaster models were done with the examiners to provide the validity of the results.The clinical examinations were performed in school dental ordinations.In one session not more than 20 children were examined to avoid tiredness of the examiners.Following the World Health Organization (WHO) criteria and recommendations for oral health examinnations, WHOtype periodontal probe and No. 5 plain mouth mirror were used.The used indices were IOTN, DHC, and AC.The DHC consists 5 grades.Grade 1 and 2 represent slight or no treatment need, grade 3 moderate and grade 4 and 5 represent great need of orthodontic treatment.AC consists a scale of 10 color photographs showing 10 levels of dental attractiveness starting with most attractive dentition (grade 1).Grade 1 to 4 represent slight or no treatment need, grades 5 to 7 moderate and grades 8 to 10 represent great need for orthodontic treatment.
To test intra-examiner agreement, 65 of the referred population were re-examined, 6 weeks after their initial examination.The assignment of grades was also done by two examiners to test inter-examiner agreement.Kappa statistics 16 was used to evaluate the consistency of both intra-examiner and inter-examiner agreement.
The data were recorded on examination record forms and processed and stored in the access database.Statistical analysis was undertaken using the Statistical package for Social Sciences (SPSS Inc., Chicago, Illinois, USA) version 12.0.We analised the IOTN results regarding gender using the 2 -test.The differences greater than (p < 0.05) were considered statistically significant.

Results
The kappa values of the intra-examiner reproducibility for the DHC and AC were 0.88 and 0.80, respectively.On the other hand, the kappa values of the inter-examiner for the DHC and AC were 0.84 and 0.78.
The distribution of the results of the orthodontic treatment need in relation to DHC IOTN is shown in Table 1.Considering DHC IOTN 27.4% of school children from Niš showed great (grades 4-5), 41.0% moderate (grade 3) and 31.6%slight or no treatment need (grade 1-2).There were no statistically significant gender differences in the determined treatment need using the DHC ( 2 = 1.78; p = 0.183).The distribution of the results of the orthodontic treatment need in relation to the AC IOTN is shown also in Table 1.Considering the IOTN AC, 15.3% of school children from Niš showed great (grade 8-10), 24.3 % moderate (grade 5-7) and 60.4% slight or no treatment need (grade 1-4).No statistically significant gender differences in treatment need determined using the AC were found ( 2 = 0.37; p = 0.543).

Discussion
The conducted study is one of the first epidemiological studies on malocclusions using IOTN on the territory of the town of Niš.The obtained results allow comparisons with the other regions of Serbia as well as with the results obtained in Europe and other parts of the world.The present results are not totaly representative because of the fact that 37% of the examined children had the history of orthodontic treatment and they were excluded from the study.
In this study, the intra-examiner kappa values were 0.88 and 0.80 for the DHC and AC, respectively.The intraexaminer kappa values were 0.84 and 0.78 for the DHC and AC, respectively.When these values were analyzed, almost perfect agreement was obtained for the DHC and substantial agreement for the AC.
Taking into consideration IOTN DHC, our result of 27.4% of the children with the great need for orthodontic treatment is similar to the results obtained in the Southern Italy, (27.3%) 17 , and in Spain, (21.8%) 18 , while substantially smaller than those obtained in Sweden (37%) 19 , Turkey (38.8%) 20 and Malaysia (47.9%) 21.Significantly lower DHC IOTN value is found in Iran (18.4%) 22 and the Western Sahara (18.1%) 23 .According to AC IOTN our results 15.3% of the children with the great need for orthodontic treatment is similar to those obtained in the Western Sa-hara 23 (13.7%), while higher values are obtained in Malaysia (22.8%) 21.Most of the authors, however, received very low values of AC IOTN: in Iran 8.7% 22 , Spain 4.4% 18 , Turkey 4.8% 20 , Sweden 2.3% 19 .In our study there are no gender differences in the distribution of the orthodontic treatment need.These results are in the line with the results of many studies 17,20,23 .
The percentage of children with the history of orthodontic treatment (37%) is incredibly high compared to the results obtained in the Western Europe 18,24,25 .In the UK the percentage of orthodontically treated children aged 15-16 is 14%, France 2.4%, and 26.6% in Spain.This is a fact which is important to know when interpreting the results obtained after determining the IOTN only in children who did not have the history of orthodontic treatment.

Conclusion
The use of the Index of Orthodontic Treatment Need in epidemiological studies can be useful for comparing the need for orthodontic treatment in different populations and planning and improving the healthcare system of the society.The need for orthodontic treatment in school children in the town of Niš, Serbia, is similar to the need in most European countries, despite of the fact that the number of children orthodontically treated is much higher as compared to European countries.

Table 1 Influence of gender on Dental Health Component (DHC) and Aesthetic Component (AC) of treatment need frequency [expressed as Index of Orthodontic Treatment Need (IOTN) grade]
Fox NA, Daniels C, Gilgrass T. A comparison of the index of complexity outcome and need (ICON) with the peer assessment rating (PAR) and the index of orthodontic treatment need (IOTN).Br Dent J 2002; 193(4): 225 30.