Color perceptibility and validity of silicon carbide-based protective coatings for dental ceramics

Statement of problem. A silicon carbide (SiC) protective coating has been developed for dental ceramics, but whether the coated ceramics can match the classical VITA shades is unclear. Purpose. The purpose of this observational in vitro study was to evaluate the color adaptability of SiC-coated dental ceramics by testing the hypotheses that SiC-coated disks can be fabricated to match standard tooth shades and have a perceptible color match rate of at least 50% for disks with a color difference (Delta E)<2.0. The effects of Delta E, shade hue, shade value, observer sex, years of experience, profession, and shade guide orientation on color perception were studied. Material and methods. SiC-coated disks were fabricated to color match (Delta E-ab<3.3) all 16 VITA classical shades. Uncoated disks of each VITA shade were used as the reference materials to determine whether the SiC-coated disks were color matched to the classical VITA shade guide. Three Delta E formulas (76, 94, and 2000) were applied and compared. Participants (N=120) with an average of 22 years of experience included dental school students, dental faculty members, and dental assistants. Pseudoisochromatic plate and the Farnsworth D-15 Panel test for assessing color deficiency and color blindness were administered. Participants then attempted to match SiC-coated disks to standard shade guides arranged by value or hue. All spectrophotometer readings and color matching were conducted in a light booth with standardized daylight illumination. Statistical analysis used the Fisher's exact test to determine factors associated with improved matching performance (alpha=.05). Results. A significant difference in color match rate was found between disks with Delta E<2.0 (63.9%) and Delta E >= 2.0 (41.7%) (P<.001). Arranging shade by value (72.2%) instead of hue (67.2%) produced better color matching (P<.001). Sex (P=.430), profession (P=.708), and years of experience (P=.902) had no significant influence on color matching. Conclusions. SiC-coated disks were successfully fabricated to match all VITA classical shades, and clinical visual color matching results confirmed that Delta E was a useful metric in optimizing color matching for the SiC-coated dental ceramics.

Automated summary

This study aimed to evaluate the color adaptability of SiC-coated dental ceramics and verify if SiC-coated disks can match standard tooth shades. The results showed that Delta E was a useful metric in optimizing color matching for SiC-coated dental ceramics.