Applicability of the aesthetic component of the index of complexity, outcome and need of orthodontic treatment (ICON), by three non-calibrated panels of evaluators

Abstract

Introduction: The occlusal indices, particularly those that measure the need for orthodontic treatment, have arisen to assess and prioritize the malocclusion’s need for treatment. Its use minimizes the subjectivity related to diagnosis, evaluation of the result and complexity of the orthodontic treatment [1]. The index of complexity, outcome and need of orthodontic treatment (ICON) is the only index that measures all three variables with only one protocol [2]. However, it has some limitations, namely the excessive weight and subjectivity assigned to the aesthetic component [2]. Therefore, this pilot study aims to evaluate the applicability of ICON’s aesthetic component by non-calibrated panels of evaluators.

Materials and methods: This study was submitted to the Egas Moniz Ethics Committee (Protocol 468). Twelve frontal intraoral photographs of patients with four anterior aesthetics displays were evaluated. Three versions of an online inquiry were created (with random different orders of the photographs) so that the evaluators could classify the aesthetic attractiveness of each case from 1 to 10, being 1 the most attractive and 10 the least. This evaluation was made using ICON’s aesthetic component scale as reference. The evaluators were divided in three non-calibrated groups, in order to verify if the professional training level was a differentiating factor in the dental aesthetic assessment: orthodontic specialists (n=28), non-specialists working in orthodontics at Clínica Dentária Universitária Egas Moniz (n=21) and final year dentistry students from Instituto Universitário Egas Moniz (n=52). Data analysis was performed using IBM SPSS Statistics version 24.0 for Windows (Armonk, NY: IBM Corp.). The statistical analysis comprised descriptive measures and inferential median comparisons, by using non-parametric tests. The level of significance was set at 5%, in all comparative statistical inference analyses.

Results: Figure 1 shows the median of the answers by the three groups, with higher median values (in the range 3–9) obtained for the orthodontic specialists (A) group, followed by the non-specialists working in orthodontics (B) (range 2–8) and dentistry students (C) (range 2–7). Nonetheless, the observed differences between professionals (A + B) and students (C) were not found to be statistically significant, except for photograph nº 5 (p = 0.012, Mann-Whitney test). However, when comparing groups A and B, the evaluation of all photographs, except for nº 3, was significantly different (p < 0.05, Mann-Whitney test).

Figure 1. Median, as a function of intraoral photograph, for the answers of the three groups: orthodontic specialists (blue), nonspecialists working in orthodontics (red) and students (green).

Discussion and conclusions: Based on these results it is possible to conclude that the professional training level influences the aesthetic evaluation using ICON’s scale, when comparing orthodontic specialists with non-specialists.