Dental Aesthetic Index among Nepalese Orthodontic Patients

Malocclusion is defined as the irregularity of teeth or malrelationship of the dental arches beyond the normal. It is the third most common dental health problem worldwide concerning with facial esthetics, dental appearance and dental health of the people.1,2 Occlusal indices are the methods to determine the amount of deviation from normal occlusion; frequency, severity and level of treatment need among individual patient or population.3 Many occlusal indices have been proposed to categorize the malocclusion frequency, severity and treatment need.4


INTRODUCTION
Malocclusion is defined as the irregularity of teeth or malrelationship of the dental arches beyond the normal.
It is the third most common dental health problem worldwide concerning with facial esthetics, dental appearance and dental health of the people. 1,2Occlusal indices are the methods to determine the amount of deviation from normal occlusion; frequency, severity and level of treatment need among individual patient or population. 3Many occlusal indices have been proposed to categorize the malocclusion frequency, severity and treatment need. 4 Dental Aesthetic Index (DAI) was introduced by Cons et al in 1986 as an epidemiological tool to rank dental esthetics and orthodontic treatment need on a scale of social norms for a socially acceptable dental appearance which links mathematical, objective (occlusal), clinical, common complaints with which the patients come for orthodontic treatment. 1The objective of the study was to assess malocclusion severity level and orthodontic treatment need in referred Nepalese orthodontic patients using Dental Aesthetic Index (DAI).

RESULT
The study sample consisted of 150 pre-treatment orthodontic study models in which 60.66% belonged to female patients.The DAI scores obtained from the present study ranged from 19 to 62, with the mean DAI score 34.59 (SD 9.88).Anterior incisal segments irregularity, maxillary overjet, and midline diastema were found to be of higher prevalence among all occlusal traits.The frequency distribution of each occlusal trait is shown in  In fact, many of these shortcomings are addressed by Index of Orthodontic Treatment Need (IOTN) with dental health and aesthetic components with greater reliability and wider applicability. 12However, DAI can be used directly in patients' mouth, even a trained dental auxiliaries can use it reducing the cost and reducing burden on orthodontist. 8,10ing a developing country, Nepal does not have publicly funded dental treatment program or dental insurance policy to cover orthodontic treatment; people have to pay on out-of-pocket expenditure for their orthodontic treatment.
On this scenario, the use of DAI as an epidemiological tool or a screening device shows a good promise to evaluate malocclusion severity and to prioritize treatment need among Nepalese population.Surveys on larger scale should be carried out in both community and clinical set-up involving government health service and dental institutions.

CONCLUSION
The highest prevalence of malocclusion severity among Nepalese orthodontic patient sample was 'very severe' or 'handicapping' malocclusion with mandatory need

A
total of randomly selected 150 pre-treatment study models of 91 female and 59 male were collected from the Department of Orthodontics, Kantipur Dental College Teaching Hospital & Research Center, Kathmandu.The study was conducted during April-June 2015.The study was designed as an observational, retrospective, crosssectional study.Good quality pre-treatment study models having unbroken teeth were chosen for the study.The study models of the orthodontic patients with permanent dentition having all teeth fully erupted (except third molar) were included in the study.Any study model of orthodontically pre-treated cases and patients with congenital anomaly were excluded from the study.DAI consists of 10 occlusal traits related to dentofacial anomalies assessing the dentition, spacing and occlusion.The ten occlusal traits include: number of missing teeth (incisor, canine, premolar), crowding in the incisal segment, spacing in the incisal segment, midline diastema, largest anterior irregularity in maxilla, largest anterior irregularity in mandible, anterior maxillary overjet, anterior mandibular overjet, vertical anterior open bite and antero-posterior molar relationship.DAI components were assessed by a single examiner from each pair of study models using graduated periodontal probe and metallic scale.The findings were recorded in a predetermined performa to evaluate total DAI score.Obtained component scores were multiplied with calculated weight of standard DAI method to find the cumulative DAI score to differentiate the severity of malocclusion and orthodontic treatment need.DAI score was calculated using the regression equation of 10 occlusal traits: "(visible missing teeth × 6) + (crowding) + (spacing) + (midline diastema × 3) + (anterior maxillary Shrestha RM, Lamichhane B, Sharma AK, Shrestha S: Dental Aesthetic Index among Nepalese Orthodontic Patients irregularity) + (anterior mandibular irregularity) + (anterior maxillary overjet × 4) + (anterior mandibular overjet × 4) + (anterior vertical open bite × 4) + (antero-posterior molar relationship × 3) + 13(constant)". 1,2,7Obtained score were recorded on DAI score chart.Chart 1 shows the reference for DAI scoring criteria classification.Pretest was done on 10 study models by the single examiner at the interval of one week.The attained reliability (kappa value 0.86 intra-class correlation coefficient) was in agreement with the recommended standards.Statistical analyses were done using SPSS Version 20; descriptive statistical data were calculated for DAI scores and occlusal traits.Gender variation was compared using chi-square test with the significance level of p<0.05.
Shrestha RM, Lamichhane B, Sharma AK, Shrestha S: Dental Aesthetic Index among Nepalese Orthodontic Patients DISCUSSION Dental Aesthetic Index was used in the present study for its simplicity, reliability and validity; which has not been used on Nepalese samples in the past.Standard method without any modifications or adaptations was used in the study.The DAI scores in our sample ranged from 19-62, with the mean DAI score 34.59 indicating that the majority of orthodontic patients having severe or very severe malocclusions with mandatory treatment need.The mean DAI score in Peruvian samples was 28.87; indicating that lesser Peruvian samples having severe or very severe malocclusion. 8On dichotomizing the DAI scores as "no need for treatment DAI ≤ 25" and "in need of treatment DAI > 25"; nearly 81% Nepalese patients required orthodontic treatment and 19% required little or no treatment.Among similar studies; 89% Rwandese samples required orthodontic treatment, 1 almost 60% Peruvian young adults required orthodontic treatment, 8 and 97% Indian patients required orthodontic treatment. 10The distribution of severity of malocclusion in Nepalese orthodontic patients is comparable to other population samples.The present study found 43.3% Nepalese orthodontic patients having very severe or handicapping malocclusion, while Goyal et al found 51% Rwandese samples having handicapping malocclusion. 1Poonacha et al found 82% of the Indian sample having severe or very severe malocclusion. 10Among the occlusal traits, incisal crowding, anterior irregularity and increased overjet were the most frequently observed orthodontic problems; while anterior open bite and mandibular overjet (anterior crossbite) showed low prevalence rates in Nepalese subjects.Despite incorporating 10 major occlusal traits, DAI cannot be considered as a sole criterion to determine the orthodontic treatment need.DAI considers crowding and spacing in incisal region only, while crowding in canines and premolar region is also esthetic concern.DAI has the limitation to exclude other occlusal traits that are equally significant in concluding the severity level of malocclusion and treatment plan.Buccal cross bite, labially or palatally erupted canines and premolars, midline discrepancy, deep and traumatic bite, supernumerary teeth, extracted posterior teeth with mutilated dentition, posterior open bite, cleft palate problems etc. are some of the malocclusions that can affect the orthodontic treatment need. 11In addition, DAI component measurements are made using a millimeter probe, even a small error can have an exaggerated effect on the cumulative DAI scorebecause of the score multiplied with regression coefficient.6,10

Table 1 .
According to the study; 43.3% had very severe

Distribution of sample according to DAI severity level Figure 2: Comparison of gender with respect to DAI score
Shrestha RM, Lamichhane B, Sharma AK, Shrestha S: Dental Aesthetic Index among Nepalese Orthodontic Patients