A feasible, aesthetic quality evaluation of implant-supported single crowns: an analysis of validity and reliability

To test the reliability and validity of six aesthetic parameters and to compare the professional- and patient-reported aesthetic outcomes.

Thirty-four patients with 66 implant-supported premolar crowns were included. Two prosthodontists and 11 dental students evaluated six aesthetic parameters, the Copenhagen Index Score (CIS): (i) crown morphology score, (ii) crown colour match score, (iii) symmetry/harmony score, (iv) mucosal discolouration score, (v) papilla index score, mesially and (vi) papilla index score, distally. The intra- and inter-observer agreement and the internal consistency were analysed by Cohen's κ and Cronbach's α, respectively. The validity of CIS parameters was tested against the corresponding Visual Analogue Scales (VAS) scores. The Spearman correlation coefficients were used. Six aesthetic Oral Health Impact Profile (OHIP) questions were correlated to the CIS and the overall VAS scores.

The intra-observer agreement was >70% in 2/3 and >50% in all observations. The inter-observed agreement was >50% in 4/5 of all observations. The mucosal discolouration score had the overall highest observed agreement followed by the papilla index scores. The crown morphology and the symmetry/harmony scores had the overall lowest agreement. The Cronbach α value was over 0.8 for all observers. All CIS scores demonstrated significant (P<0.0001) correlation to the corresponding VAS scores. Low correlation coefficients (CIS/OHIP: r(s) <0.36; VAS/OHIP: r(s) >-0,24) were found between patient and professional evaluations.

The feasibility, reliability and validity of the CIS make the parameters useful for quality control of implant-supported restorations. The professional- and patient-reported aesthetic outcomes had no significant correlation.