The Study On Extrinsic Coloration Dye Solution Of ZY-1Silicone Elastomer Maxillofacial Prosthesis

Color matching and copy of the surface of the prosthesis is still need the doctor basedon clinical experience, and with reference to the patient’s skin color by hand, the doctordifferences in color discrimination ability, subjective of adding pigment, psychologicalfactors, as well as lighting conditions and other factors are affecting the prosthesis colorsimulation. Therefore, demanding of the coloring process is high for the doctor, which isthe main reason for the difficulties to train general prosthetic practitioners. The traditionalpigments directly coloring not only take a long time, the final color of the surface is difficultto deploy and grasp, and silicone elastomer and pigments are mixed, prosthesis surface isthickness, surface texture depth and three-dimensional is reduced. Therefore, changing thetraditional coloring has important clinical significance for improving prosthetic simulation,reducing the difficulty of production, reducing production time, and simplifying theproduction process. Abroad with the extrinsic coloring dye solution system of prostheticmaterial supporting (including silicone rubber, pigments, solvents, closed, etc), and fordomestic there is no the extrinsic coloring dye solution system of ZY-1prostheses with silicone rubber supporting. Therefore, the possibility of using the existing conditions toprepare extrinsic coloring dye solution applicable in the ZY-1prostheses with siliconerubber and shifting from the traditional pigments direct coloring to dye solution coloring isthe focus of the current research in the field, and laying the foundation for preliminaryexploration of computer-aided extrinsic coloring printing technology of facial prosthesis.This study was to determine solubility of oil pigments in different solvents, comparethe size of its solubility, prepare the extrinsic coloration dye solution which is applicable tothe ZY-1silicone elastomer. To determine chromaticity values of the dye solution in thenatural aging conditions in the silicone elastomer and evaluate its color stability and itsclinical application effect. Further exploring the effect of polyvinylpyrrolidone (PVPK30)to improve the dispersion stability of the dye solution and determining its the optimumdosage. Determining and evaluating PVPK30on the changes of the viscosity and surfacetension of the dye solution.The paper includes four parts，evaluating application prospectsof extrinsic coloring dye solution in computer-aided extrinsic coloring printing technologyof facial prosthesis.Part1Preparing extrinsic coloration dye solution of ZY-1silicone elastomerIn this study, analyzing solubility of soil red、cadmium red、the Rose Madderi oilpigments in n-butanol，n-trichloroethane，hexamethyldisiloxane and decamethylcyclopen-tasiloxane by a UV-VIS spectrophotometer for preliminary screening the optimumsolvent. The results showed that similar of three pigments in the solubility of the foursolvents in descending order: n-butanol> n-trichloroethane> hexamethyldisiloxane>decamethylcyclopentasiloxane. The solubility of soil red、cadmium red、the Rose Madderioil pigments in n-butanol were1.6465g/L,0.7238g/L.5174g/L, soil red was greaterthan the solubility of the other two pigments so that it was determined the n-butanol as thesolvent of extrinsic coloring dye solution used for research.Part2Research of color stability on extrinsic coloration dye solution of ZY-1siliconeelastomerIn this study, we measured in natural aging and protected from light the chrominance value and color difference ΔE of extrinsic coloring dye solution on silicone rubber by thecolorimeter. The experimental results showed that in the natural aging or dark storageconditions, ΔE values of each specimen group were significantly different, but after6months natural aging ΔE was1.86, less than2.0, the naked eye can not detect the twocolor differences that showed it had a good color stability. In the natural aging or the darkcolor difference were gradually increased, color changes in the natural aging were moreobvious than stored in the dark, that suggested that the color stability of silicone elastomerwere related with their way of preserving, and with minimizing or avoiding light. You canslow fading of silicone elastomer prosthesis.Part3Research of clinical application on extrinsic coloration dye solution of ZY-1silicone elastomerIn this experiment, oil pigments dye solution prepared by n-butanol as extrinsiccoloring dye solution of prosthesis was evaluated clinically. The clinical effect:simplifying the coloring process, reducing the difficulty of the production, reducingproduction time, the surface texture had a sense of depth and dimension of the skin,patient felt satisfaction.Part4The study of polyvinylpyrrolidone (PVPK30) on improving of dispersion stabilityof the extrinsic coloring dye solutionThis experiment was observed contrastly by microscopic change of the particle sizeof the pigment before or after adding PVPK30, and analyzed the impact of the amount ofPVPK30on absorbance values and centrifugal sedimentation ratio. The results found thatbefore or after centrifugation, the pigment particle size with not adding PVPK30werelarge and showed the state of aggregation, the pigment particle size were reduced afteradding PVPK30, and distributed evenly, which indicated PVPK30on the pigment hadobvious dispersion effect. After adding PVPK30with the time extending, pigmentsvisually observed had deposition of different degrees, while using UV spectrophotometerit is found that the absorbance value of the solution was reduced. Add the differentconcentration PVPK30the centrifugal sedimentation ratio can be obtained by measuring the weight of the pigment precipitate after centrifugation. The results showed thatcentrifugal sedimentation ratio gradually decreased with the increasing of PVPK30, inPVPK30relative content for1.2g centrifugal sedimentation lowest percentage was5.26%,the dispersion stability of the solution was best, and there was no obvious deposition forstanding one months; PVPK30relative content of more than1.2g, the dispersion stabilitywas not improved.Thus, PVPK30was obvious for dispersion of pigment particles in the dye, which caneffectively improve the dispersion stability of the dye solution, but the amount of PVPK30in the stable dispersion of the oil pigment dye solution existed an optimum value, so wecan determine per100ml n-butanol the best quality ratio of PVPK30and oil pigmentwas12:1.when the optimum value was exceeded, the excess of PVPK30but not conduciveto the dispersion stability of the pigment.Part5Polyvinylpyrrolidone (PVPK30) on effect of viscosity and surface tension of theextrinsic coloring dye solutionAdding PVPK30into dye solution, the viscosity of the dye solution is determinedthrough the viscometer, and using the hanging drop method determined dye solutionsurface tension by the surface tension meter. It showed that the viscosity increased, surfacetension decreased. When dispersion stability of the dye solution was best and PVPK30relatively content was1.2g, viscosity was23.77mPa.s that was greater than the viscosityindex range of the printing dye solution; surface tension was17.63mN/m that wassmaller than the index range of the printing dye solution.In summary, the extrinsic coloring dye solution applicable to the ZY-1siliconeelastomer had good color stability. After adding PVPK30the dispersion stability of thedye solution was greatly improved. PVPK30can have viscosity of the dye solutionincreased and the surface tension decreased. If this dye solution was used incomputer-aided extrinsic coloring printing of silicone elastomer, it should need to considerthe PH value of the dye solution、conductivity、the number of suspended particles、color、the number of colors generated (referred to as the color gamut of the color) and otherproperties for the effect of print nozzles and accuracy、speed and quality of print color, which required further in future studies to add auxiliary ingredients to adjust the physicaland chemical properties of dye solution.