Medição digital de cor gengival e de cor de resinas produzidas para a caracterização de bases protéticas: um método fotográfico para a confecção de uma escala de cores

Abstract

This study aimed at the use of a new method for evaluating gingival color and color of resins produced for the characterization of prosthetic bases in order to make a color scale, in order to facilitate / standardize this practice that improves the aesthetic quality of the rehabilitations as well How to facilitate communication between dental surgeons and dental technicians. A total of 176 specimens were prepared from the blend of graphite powder (Vonder®), red self-curing resins (Dencrilay®, Duralay® and Cop Clas® brands), yellow resin color 69 (Dencor Clássico®) and thermo-polymerizable resin B with Veins (TDV®), in pre-established proportions, obtaining several shades of pink, purple, purple, red, gray, brown and orange. From this total, 40 specimens were discarded, in a visual and subjective way, whose colors were very different from the existing gingival tonalities, delimiting the sample of this work in 136 test specimens of colored resins more similar to the gingival tonalities. Each test piece was photographed in a closed room, illuminated by daylight neon lights with color temperature of 6,500K, reproduction index of 97, and lightness from 1000 to 1600 lx, + with Camera Canon T3i, macro lens 100, setting: Speed 1/60; Opening F11; Iso 800; Neutral Color Pattern; Tungsten White Balance. The photos were transferred to the computer and color measurements were taken with Mac OSX Lyon software, which performs digital color reading directly from photographs, by the CIE system L * a * b *. The results revealed significant relationships between the different proportions of material used as pigment and the corresponding values in the digital color measurement. In a second moment, photographs of gums were selected and transferred to the Mac Book computer, which were also subjected to color measurements with Mac OSX Lyon software. The color measurements of the resins and gums were compared, and 74 corresponding tones were found / compatible with the natural colors of the gingiva. The digital color measurement process proved to be more objective and precise than visual perception, and simpler, less invasive and costly compared to the use of spectrophotometers. The next step will be to take standardized photos of gums and repeat the process to make a color scale.