Optical properties of base dentin ceramics for all-ceramic restorations.
OBJECTIVE
The study was conducted to compare the optical parameters of VM7(®) M-shade base dentin ceramics (VITA, Germany) for all ceramic restorations to the chemical composition across the 3D-MASTER(®) shade system.


METHODS
Three disc samples, 13 mm diameter and 1.4 mm thickness, were produced for each M-shade following the manufacturer's instructions. Each disc was ground and polished to a thickness of 1.0 mm. Spectral light transmittance and reflectance data were recorded in the visible spectrum under the standard illuminant D65 and 2° observer at 10 nm intervals by using a computer-controlled spectrophotometer. Opacity, translucency and opalescence parameters were determined for each sample.


RESULTS
(1) Spectral transmittance and reflectance in the short-wavelength range systematically decreased with increasing chroma number (M1, M2, M3) when compared within the same value (lightness) group. (2) Spectral transmittance and reflectance decreased systematically across the whole visible spectrum with increasing value group number when compared within the same chroma group. (3) Analysis of relationship between chemical composition and various optical parameters for all the samples showed the significant contribution of ZrO₂ and Y₂O₃ substances to optical properties of the present material.


CONCLUSIONS
Systematic variations in optical properties of VM7(®) M-shade base dentin ceramics were observed throughout the 3D-MASTER(®) shade system and were suggested to be caused by the fine structure of the sample which can interfere with shorter wavelengths in the visible spectrum.
Department of Dental and Biomedical Materials Science, Unit of Basic Medical Sciences, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8588, Japan. siraisi@nagasaki-u.ac.jp
Takanobu
T
Shiraishi
Duncan J
DJ
Wood
Nobuya
N
Shinozaki
Richard
R
van Noort
D000042:Absorption; D000538:Aluminum Silicates / Q000737:chemistry; D002516:Ceramics / Q000737:chemistry; D003116:Color; D003775:Dental Polishing; D003776:Dental Porcelain / Q000737:chemistry*; D017266:Dental Prosthesis; D003804:Dentin; D005898:Glass / Q000737:chemistry; D006801:Humans; D008027:Light; D008422:Materials Testing; D055620:Optical Phenomena; D017680:Potassium Compounds / Q000737:chemistry; D017797:Prosthesis Coloring / Q000295:instrumentation; D012542:Scattering, Radiation; D013052:Spectrometry, X-Ray Emission; D017971:Tin Compounds / Q000737:chemistry; D017968:Vanadium Compounds / Q000737:chemistry; D015019:Yttrium / Q000737:chemistry; D015040:Zirconium / Q000737:chemistry
D000538:Aluminum Silicates; D017680:Potassium Compounds; D017971:Tin Compounds; C556625:VITA VM7; D017968:Vanadium Compounds; D003776:Dental Porcelain; C016447:feldspar; D015019:Yttrium; C066075:vanadium pentoxide; D015040:Zirconium; C045358:stannic oxide; C028541:zirconium oxide; C091417:yttria