Reproducibility of the Implant Crown Aesthetic Index - Rating Aesthetics of Single-Implant Crowns and Adjacent Soft Tissues with Regard to Observer Dental Specialization

Aim: The Implant Crown Aesthetic (ICA) Index evaluates the aesthetic outcome of implant-supported single crowns in the anterior zone by awarding nine points for the shape, color, and surface characteristics of the crowns and surrounding soft tissue. The aim of this study was to measure the reproducibility of the ICA Index and assess the influence exerted by the examiner's degree of dental specialization. Materials and Methods: Ten examiners (two general dentists, two prosthodontists, two oral surgeons, two orthodontists, and two dental technicians) applied the ICA Index to 23 implant-supported single crowns twice at an interval of 4 weeks. The inter- and intra-examiner ratings were analyzed. Cohen's kappa (K) was used to measure the interexaminer reliability of estimations by two appraisers at a significance level of p < .05. Results: Within the various parameters, the observer agreement ranged 53 to 81%. All the examiners achieved moderate agreement between the first and second ratings, whereby Cohen's kappa was 0.49 (p < .001). The most agreement was obtained by surgeons (K = 0.62, substantial) and the least by orthodontists (K = 0.24, sufficient). The lowest level of agreement with other occupational groups was manifested by the orthodontists (< 44.3%). The ICA Index produced a moderate Cohen's kappa of 0.42 and agreement amounting to 67% between the two ratings within the occupational groups. There was minimum agreement among the occupational groups (Cohen's K = 0.11-0.37, observer agreement: 40.2-66.3%); again, the least agreement was between the orthodontists and others. Conclusions: The ICA Index resulted in poor to moderate intra- and interexaminer agreement. The validity and reproducibility of the ICA indexing as an objective tool in rating implant aesthetics is questionable.