Esthetic evaluation of single implant-supported prostheses: Comparative analysis of the reliability of the esthetic indices

Objectives To carry out a detailed analysis of four indices proposed for the esthetic evaluation of implant-supported single crowns in the anterior maxillary sector. Material and methods Four esthetic indices were selected: the Pink and white esthetic score, the Copenhagen Index Score, the peri-implant and crown index (PICI), and the implant restoration esthetic index (IREI). The examiners were 15 expert subjects and 30 nonexpert ones. The intraclass correlation coefficient was used to assess reproducibility. The validity and the correlation of the esthetic indices results with the perception of nonexpert subjects were evaluated using the Pearson's correlation. Results For inter- and intra-observer reproducibility, all the esthetic indices had an intraclass correlation coefficient value>0.8. As for validity, the highest correlation values were found for the PICI and for the IREI. The values of correlation with the perception of nonexpert subjects did not exceed 0.3 for all esthetic indices. Conclusions All esthetic indices evaluated presented good intra- and inter-rater reproducibility. Validity was considered satisfactory only for the PICI and the IREI. The correlation with the perception of nonexpert subjects showed a weak correlation with all the indices considered. Clinical significance An approved esthetic indice with proven reproducibility and validity could provide a better objective overview of one's own esthetic results in the daily practice. It could also help to record the results over time to analyze the stability of the treatment procedure. The esthetic results of the different surgical and prosthetic protocols can also be compared, which facilitates the analysis of the indications relevance and clinical effects. However, low reproducibility according to the specialty and the practitioner's level of expertise was observed. A heterogeneity of results was also noted when compared with those of nonexpert subjects.