Applicability of the IOTN-AC index in a bimaxillary protrusion population

Abstract

Objective The objective of this study was to assess the validity of the IOTN-AC in the assessment of aesthetic impairment in bimaxillary protrusion patients. Materials and methods A cross-sectional study was conducted and involved 110 patients comprising 52 males (47.3%) and 58 females (52.7%) who were accepted for fixed appliance treatment at The University of the West Indies Dental Hospital and provided consent for the use of their records. The mean age was 13.45 years. Participants were asked to complete a questionnaire regarding their reasons for seeking orthodontic treatment and score their self-perceived IOTN-AC. An orthodontist also scored the malocclusion using the IOTN (AC and DHC). Results Spearman’s correlation between patient IOTN-AC and orthodontist IOTN-AC was r = 0.435, (p < 0.001). However, the patient IOTN-AC and the ‘normative’ need (p = 0.198), as well as the orthodontist IOTN-AC and the ‘normative’ need (p = 0.334), were not correlated (r = 0.124 and r = 0.094, respectively). Both patient and the orthodontist IOTN-AC scores were not in agreement with ‘normative’ need (IOTN-DHC). Cohen’s kappa test determined an agreement between the patient’s IOTN- AC and an orthodontist’s IOTN AC score, k = 0.395, p < 0.001. The questionnaire revealed aesthetics as the primary reason for seeking treatment but there was poor correlation between the questionnaire items and the patient or orthodontist IOTN-AC score, an AC score of 3 being the most common score for both. Conclusion The IOTN-AC is not a valid tool to determine patient perception of the need for treatment in a bimaxillary protrusion population when scored by either patients or orthodontists.