Base Research On Color Matching Of Dental CAD/CAM Fluorine Mica Glass-Ceramic

CAD/CAM all-ceramic restoration technologies have been accepted by more and more doctors and patients of all ages for safety, aesthetics and fast way to repair. At present, the main materials used for CAD/CAM all-ceramic system were machinable ceramics.Fluorosilicic mica glass -ceramic have became a kind of favourable dental CAD/CAM all-ceramic materials for its proximity with the teeth of the semi-transparent and better mechanical properties, however, commercial fluorosilicic mica glass -ceramic still need to be stained or prepared by dentine porcelain, wasting manpower and time because of achromatic color, which was contradictory with the original beautiful, fast production of CAD/CAM.Rapid Prototyping Technology (RP) created a prototype exactly through the accumulation of material instead of using the original machine and cutting tools. At present, the technology has became more mature, in which three-dimensional printing (3DP) and selective laser sintering (SLS) are especially suitable to fabricate all-ceramic material, providing a new enlightenment for us of the production of CAD / CAM all-ceramic restoration in clinical rapidly: add an appropriate proportion of ceramic pigment in all-ceramic materials when form the restoration using three-dimensional printing technology, and then sinter it by laser, in this way the prosthesis can match the color with natural teeth. As RP technology and computer-assisted color matching technology have developed maturely, this experiment aimed to do the researches as follow: on the basis of the preliminary studies of the K₂O-MgO-MgF₂-SiO₂ glass system, to conduct a comparative study of two different colored Process ,and to select suitable ceramic pigment; to do the Colorimetric Experiment to checkout whether the pigment can be measured and added or not ,to provide experimental evidence for computer color matching.Content and methods:1. The objective of this study was to evaluate the coloration effects of Zr-based iron oxide red pigment using melting and sintering processes, respectively. In order to elect more suitable fluorosilicic mica glass-ceramics of the coloring process for the next coloring step process.2. Fluorosilicic mica glass-ceramics by sintering method with four different types of pigment : Zr-based iron oxide red, chrome-tin pink, chrome aluminum red, iron oxide red, and observe the effect of pigments to the microstructure and the color of blocks. The objective of this study was to selecte suitable ceramic pigment for fluorosilicic mica glass-ceramics.3. The monochromatic fluorosilicic mica glass-ceramic samples with different concentrations of zirconate-based pigments were prepared and their chroma values and reflective spectrums were mensurated and investigated.Results:1. Fluorosilicic mica glass-ceramics colored by melting were colorless and translucent glass-ceramic-like; the blocks colored by sintering were red and the color was stable with color value of L: 63.32±0.14, a: 12.44±0.11, b 9.55±0.14 .2. The four kind of pigments had not obviously influenced the microstructure of the colored mica glass ceramic, chromatic aberration of the colored mica glass ceramic samples were less than 0.65, hue angle of Zr-based iron oxide red group by sintering process had no difference(P>0.05), and the three others had differences(P<0.05), especially hue angle of iron oxide red group.3. pigments had different influence on chromatic value of colored fluorosilicic mica glass-ceramics , Zr-based iron oxide red and cerium- praseodymium yellow had impact on the a and b value, respectively; and nickel mainly effected the brightness. At low concentrations, with adding the three pigments concentration, the spectral reflectance curve of a specific wavelength absorptedregion were in descending trend,and the plot with different concentration of pigment were basically the same; different concentrations of curve; the K/S of colored mica glass ceramic samples met the linear relationship with the concentration.Conclusions:1. On the fluorine-mica glass-ceramic coloring process, the sintering process was better than melting coloring coloring process.2. The four kind of pigments had not obviously influenced the microstructure of the colored mica glass ceramic, and stability of the Zr-based pigments included Zr-based iron oxide red were best in the trial.3. The relationship between the concentrations of pigments and the chroma values was accorded with the principles of pigmentation, and that the spectral reflectivity groups of monochromatic samples were feasible for establishing database of computer-color-matching software.