COLOR STABILITY OF PROVISIONAL MATERIALS USED IN FIXED PROSTHODONTICS. IN VITRO STUDY BETWEEN ACRYLIC RESIN AND BISACRYLIC

The objective of this study is to evaluate the color stability of provisional materials used in fixed prosthesis by an in vitro study between acrylic and bisacrylic resin. Forty disks of acrylic resin and forty disks of bisacrylic resin were fabricated, using standardized measures; half of each group of resins were polished and the other half did not. Provisional materials were submerged in coffee and coke for a period of 24 hours. The initial and final color of the discs is quantified with a colorimeter. The 100% of the acrylic resin samples showed no color variations. The bisacrylic resin showed variations in color stability equal to 2.8 +/- SD 1.4. The polished bisacrylic resin group generated a value of 2.32 +/- SD 0.94 and in the non-polished group 3.24 +/- SD 1.60. As for the pigment substances the coffee causes color changes equal to 1.43 +/- SD 1.79. The material that best maintained its stability was the acrylic resin, since there were no clinical changes when submerged in these substances. The bisacrylic resins presented significant changes in color variation. The substance that had the highest pigmentation in the samples was coffee. Polishing significantly influences the color stability of the bisacryl resins.