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Year : 2007  |  Volume : 25  |  Issue : 1  |  Page : 10-14

The use of index of orthodontic treatment need in an Iranian population

1 Orthodontist and Assistant Professor, Dental School, Shiraz University of Medical Sciences, Shiraz, Iran
2 Orthodontic Department, Dental School, Shiraz University of Medical Sciences, Shiraz, Iran

Correspondence Address:
Z Hedayati
No: 21 Mogharabi Alley, Ghasrodasht Square 71866-77764, Shiraz
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0970-4388.31982

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This study aims to evaluate the need for orthodontic treatment between 11 and 14 year old school children in Shiraz. A sample of 2000 students consisting of 1200 boys and 800 girls from various parts of the city was selected. The index of orthodontic treatment need (IOTN) was used by two calibrated examiners. The data was recorded in questionnaires to assess dental health components (DHC). Aesthetic components (AC) were evaluated both by students (AC) and examiners (ACE). The results for DHC of IOTN were: 18.39% of population showed severe and very severe need for treatment, 25.8% were in border line category, 48.1% had a slight need and the percentage for no need to treatment was 7.63%. In evaluating AC, 91.93% were in no need or little need, 3.91% in moderate need and 4.11% in great need to treatment group. Where as ACE resulted in: 91.31% no need and little need, 2.44% moderate need and 6.21% great need to treatment. There was a slight statistical correlation (0.54) between AC and ACE, but a very weak correlation between DHC and AC was observed. According to DHC, boys showed more need for treatment than girls (P=0.001). Grade 8 showed the most percentage in great need category in both AC and ACE (3.41% of 4.11% and 5.74% of 6.21%, respectively). The results indicate that the need for orthodontic treatment was less than other studies and most of the students were in the category of little need for treatment.

Keywords: Aesthetic component, dental health component, index of orthodontic treatment need

How to cite this article:
Hedayati Z, Fattahi H R, Jahromi S B. The use of index of orthodontic treatment need in an Iranian population. J Indian Soc Pedod Prev Dent 2007;25:10-4

How to cite this URL:
Hedayati Z, Fattahi H R, Jahromi S B. The use of index of orthodontic treatment need in an Iranian population. J Indian Soc Pedod Prev Dent [serial online] 2007 [cited 2022 Sep 26];25:10-4. Available from: http://www.jisppd.com/text.asp?2007/25/1/10/31982

   Introduction Top

For many years epidemiologic studies of malocclusion suffered from considerable disagreement among investigators, especially regarding how much deviation from the ideal should be accepted within the bounds of normal. [1] For this reason several quantitative systems of assessing malocclusion and evaluating treatment need have been developed in recent years. [2],[3],[4],[5],[6],[7]

Recently Shaw et al . developed the Index of Orthodontic Treatment Need (IOTN) in the U.K. [1] This index was initially described by Brook and Shaw [8] and Shaw et al . [7] and later modified by Richmond. [9] Because of simplicity and ease of use, it became popular and is recognized as a method of objectively assessing treatment need. [10],[11]

This index ranks malocclusion in terms of the significance of various occlusal traits for the individual dental health component (DHC) and the perceived aesthetic impairment (AI), with the intention of identifying those who would likely benefit from orthodontic treatment. This index incorporates an aesthetic component (AC) and DHC. [7],[12],[13],[14] The AC was developed originally by Evan and Shaw [15] and consists of a scale of ten color photographs showing different levels of dental attractiveness. [10],[13],[16],[17]

The dental attractiveness of prospective patients can be rated with reference to this scale. Grade 1 represent the more and grade 10 the least attractive arrangements of teeth [Figure - 1]. The score reflects the aesthetic impairment.

DHC represents an attempt at synthesis of the current evidence for the deleterious effects of malocclusion and is loosely based on the index of the Swedish Medical Health Board. [13],[18]

The Swedish index was meant as a basic guide and its practical implementation called for a 'good sense of judgment.' The DHC was developed with well-defined cut-off points to reduce the subjectivity on measurement. [15]

The DHC records the various occlusal traits of a malocclusion, which would increase the morbidity of the dentition and surrounding structures. There are five grades from grade 1 'no need to treatment' to grade 5 'very great need.' Only the worst occlusal feature is recorded. The components that make up the five grades are shown in [Table - 1]. Validity and reliability of IOTN have been extensively verified in different countries by several investigators. [7],[8],[19],[20]

In many Asian populations need for orthodontic treatment has been determined by using the IOTN (So and Tang in 1993 in Hong Kong, [21] Ugur, [22] Uncuncu and Ertugay [11] in Turkey, Abdullah and Rock, [23],[24] in Malaysia, Hamdan [25] in Jordan). However, the results showed that the need for orthodontic treatment was from one third to half of the adolescent population.

Iran is a vast country with nearly a population of 70 million living in 31 provinces. Recently, especially in the past decade, due to growing public awareness on general matters the public interest and demand for orthodontic treatment have likewise shown an upward trend. The country has 16 dental schools, which offer limited orthodontic treatment. This is deemed insufficient for the national requirement considering that the treatment centers are mainly concentrated in the capital and other large cities. Therefore, in view of a significant demand for orthodontic treatment, it is important to identify those people who have orthodontic problems to prioritize them for proper treatment.

Currently, there are no research studies about this issue in connection with the Iranian population. The IOTN index, which is a simple, repeatable, and reliable index among the available range of indices and which does not require sophisticated tools and at the same is more practical compared to the other indices was chosen as the preferred measure of the degree of orthodontic treatment need.

So the main purpose of this study is to evaluate the need for orthodontic treatment between 11 and 14 year old school children in ancient city of Shiraz

   Materials and Methods Top

Our study group consisted of 2000 school children in Shiraz, aged between 11 and 14 years. Schools were selected based on random cluster sampling from different parts of the city. All the 11-14 years old children of these middle schools were examined. The sample consisted of 1200 boys and 800 girls. Thirty-five students (25 girls and 10 boys) who had already received orthodontic treatment, were excluded from the study.

Clinical examinations for evaluating IOTN were made by two calibrated examiners. Intra-examiner agreement was confirmed after re-examination of 100 children 2 weeks after initial examination. Inter-examiner agreement was also evaluated between two examiners by reassignment of groups. Both inter- and intra-examiner agreements were evaluated by using Kappa statistics.

No radiographic data were available and the examiners did not have access to any of the subjects' dental records.

The students were examined in natural daylight in one of the brightest rooms of their school, using tongue blade and a digital caliper. The data were recorded in the questionnaires. The percentages of IOTN components were determined separately. The collected data were also statistically processed by using Chi-square, t -test to compare results between boys and girls to assess the significance of the dependency on gender of DHC and AC grades. The correlation coefficient between AC, ACE and DHC was calculated.

   Results Top

Thirty-five students out of 2000 study cases had already undergone orthodontic treatment. They consisted of 10 boys (0.83% of boys) and 25 girls (3.12% of girls). From the remaining sample with respect to DHC, results showed that: 150 (7.63%) students were in the category of no need, 946 students (45.1%) in little need, 507 students (25.8%) in border line need and 250 students (12.72%) in the severe and 112 students (5.69%) were in the category of very severe need [Table - 2].

In evaluating AC, 1805 students (91.93%) were placed in the category of no need or little need, 77 students (3.91%) in moderate need and 81 students (4.11%) in great need category [Table - 3].

While professional results (ACE) revealed different distribution. With respect to AC evaluated by them it was shown that 1791 students (91.31%) were in no/slight need, 48 students (2.44%) in moderate need and 122 students (6.21%) in great need to treatment group [Table - 4].

Grade 8 showed the most percentage in great need category in both AC and ACE (3.41% out of 4.11% and 5.74% out of 6.21%, respectively).

The correlation coefficient between different components of the index was calculated.

According to these coefficients, there was weak relationship between IOTN components. In addition, there was a slight relation between AC and ACE (0.54) [Table - 5].

The correlation coefficient between AC and ACE was the same in both boys and girls (0.54) [Table - 5].

The treatment need according to DHC in boys and girls revealed that sex distribution of DHC grades was not similar in boys and girls and, 20.49% of boys were in the category of severe and very severe need. While, 15.21% of the total girls were placed in this category, therefore boys represented statistically more need ( P =0.001) [Table - 2].

   Discussion Top

According to DHC results, approximately half of the students were in the category of little need to treatment. Thirty-five students were undergoing orthodontic treatment and were excluded from the study. This does not affect the level of unmet treatment need, but results in a reduced overall assessment of the treatment need and will bias the prevalence of malocclusion. Children who already had started the treatment at 11 years of age probably had severe malocclusions that required correction. The result will be an under-reporting of some severe malocclusions that probably should be added to DHC grades 4 and 5.

The distribution of DHC and AC grades has been studied by several researchers. In the UK, Brook and Shaw [8] found that, the DHC proportions in 333 schoolchildren being 11-12 years old were 32.7% for great need and 35.1% for no/little treatment need. Burden and Holmes [12] distinguished that 21-24% of the population were in the great need category, when DHC was assessed for 1829 school children being 11-12 years old age. Ucuncu [11] found that 38.8% among 500 Turkish students aged 11-14 years old showed great need, 24.0% moderate need and 37.2% no/slight need. In Birkland et al . study, [26] of the 359 students aged 11 years old, 53.2% children had very great to moderate need and 46.8% had little to no need.

The results derived from Mandall's research [27] on 14-15 years old children from schools in Manchester showed 48, 34, and 18% for no need moderate need and great need to treatment, respectively. While in our study, the DHC scores were found as 18.41% for great and very great need that is more close to Mandall [27] results who has examined Asian and Caucasian children. But the need for treatment (including grades 3, 4, 5) was found to be 44.2%, which is more than one-third of the population and is still less than findings from other studies.

The distribution with respect to males and females of orthodontic treatment need has also been studied by several researchers. In 1999 Burden et al . [28] showed significantly more findings of need for orthodontic treatment in males than females which is in line with our findings. In our study, the difference between the IOTN values of boys and girls indicated that boys represented more need to treatment than girls ( P =0.001). Whereas there was more need for treatment among females in Mandall et al . [27] study sample and Ucuncu [11] found no significant difference between boys and girls in this field.

Most of the children in the category of need to treatment had a need for treatment or dental health grounds, although their aesthetic impairment did not fall into the most severe grades. This reflects the fact that many occlusal traits such as ectopic teeth, deep traumatic overbites or cross bites have dental health implications, but do not attract a high aesthetic component score.

The aesthetic component of IOTN seeks to quantify the likely socio-psychological effects of each child's malocclusion. Although the aesthetic component is assessed independently of the dental health component, results showed that most of the children with poor dental aesthetics were also considered to be in need of treatment on dental health grounds. This is not altogether surprising as many children with an unattractive arrangement of their teeth are likely to have discrepancies, which also have dental health implications. The small group which was scored needing treatment on aesthetic grounds, but not on dental health grounds, mostly comprised children with dentition which were considered to have unattractive aesthetics, but which were not considered to have dental health implication by IOTN, e.g., generalized spacing.

The correlation coefficient between AC and ACE was the same in both boys and girls (0.54). This indicates that both boys and girls had the same perception of the problems of their dentition and the evaluations were not affected by gender. This is in line with findings of Abdullah and Rock [24] and Birkeland. [26]

From the total girls, 25 girls (3.12%) had undergone orthodontic treatment, while just 10 boys (0.81%) were under treatment. This is similar to findings in a study by Shaw, who found that the parents pay more attention to girls' than boys' dental aesthetics.

   Conclusion Top

The need for orthodontic treatment was less than other studies and most of the students were in the category of little need to treatment.

  1. In comparison of the need to treatment according to DHC, it was concluded that boys represented more need than girls.
  2. In evaluating the correlation coefficient between AC and the ACE in boys and girls it was shown that perception of dentition problems and the assessment were little affected by gender.
  3. Parents pay more attention to girls' dental aesthetic than boys'.

   Acknowledgment Top

Authors would like to thank the Vice-Chancellor for Research at Shiraz University of Medical Sciences for kindly supporting this study financially.

   References Top

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  [Figure - 1]

  [Table - 1], [Table - 2], [Table - 3], [Table - 4], [Table - 5]

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