Conventional visual vs. spectrophotometric shade taking for porcelain-fused-to-metal crowns: Clinical comparison.

The purpose of this study was to test how well the shade of single porcelain-fused-to-metal restorations matched with the adjacent dentition when the restorations were fabricated either using data from conventional visual shade matching (conventional crown: CC) or data from a new spectrophotometric shade matching system (spectrophotometric crown: SC). The samples of a Vita Classic shade guide were measured with the spectrophotometer to determine the CIE L*a*b* color parameters. Ten patients with upper right or left incisors in need of restoration were independently assessed for best shade match by three dentists with no history of visual color deficiency. Each patient was asked to stand against a white wall away from all windows, with ceiling lighting of 5000 K. Using uniform flash lighting, a conventional photograph was taken of each patient's incisors along with the best matching shade guide teeth selected by each dentist. The 10 incisors were then measured using a reflectance spectrophotometer (SP). CIE Lab coordinates were directly recorded on the SP's18x13 square mm detector area using a standard light source (I = 400-720 nm). Resulting conventional and spectrophotometric PFM restorations were assessed intraorally for best color matching with the adjacent incisor using conventional shade matching vs. spectrophotometric measurement. The total color difference was calculated and all groups were statistically analyzed. The three dentists' and patient's crown of choice was selected for final cementation. Regarding color matching, the visual shade selections of all three evaluators concurred in 2 cases, those of two evaluators concurred in 6 cases, and all three visual shade selections differed in the remaining 2 cases. In contrast, all three spectrophotometric shade selections matched in 9 out of 10 cases. Additionally, Delta E values of visually assessed tooth shades were higher than spectrophotometrically assessed Delta E values (p < 0.02) in 9 out of 10 cases. Delta E values for conventional crowns were significantly higher than those of spectrophotometric crowns (p < 0.01).