Clinical Comparison of a Spectrophotometric Shade Matching System with Conventional Shade Matching

Objectives: To test the shade matching of single PFM restorations with the adjacent dentition if the restorations were fabricated either using conventional visual shade matching (conventional crown: CC) or using a new spectrophotometric shade matching system (spectrophotometric crown: SC). Methods: The samples of a Vita Classic shade guide were measured with the spectrophotometer to determine the CIE L*a*b* coordinates. Three dentists with a negative history of visual color deficency independently selected the best match to the upper central incisor needing a restoration on 10 patients. Each patient was standing against a white wall with ceiling lighting of 5000 K away from all windows. Pictures were taken with uniform flash light of each patient's incisor with the selections of best matching (BM) shade guide teeth of all three dentists. The 10 incisors were then measured using a reflectance spectrophotometer (SP). CIE Lab coordinates were directly recorded on the SP's 18x13 square mm detector area using a standard light source (l=400-720 nm). Resulting conventional and spectrophotometric PFM’s were tested intraorally for best match with the adjacent incisor using conventional shade matching vs. spectrophotometric measuring (øDCC, øDSC). The total color difference was calculated (øDCC - øDSC). The three dentists' and patient's choice of crown was selected for final cementation (Choice of Cr.). Results: DE values were significantly higher for conventional crowns compared to spectrophotometric crowns (Mann-Whitney, p<0.01). In 9 of 10 cases spectrophotometric crowns were preferred over conventional crowns when evaluated visually. Conclusion: Spectrophotometric shade matching could be used efficiently fabricating PFM restorations.