بررسی خطای تجمعی بازسازی رنگ در مراحل رنگ گیری تا ساخت روکش PFM در دانشجویان دندانپزشکی همدان

Introduction & Objective: The ability of dentist to select appropriate tooth color is one of the most important factors in cosmetic dentistry. The aim of this study was to examine the cumu-lative error in reconstruction of colors from shade selection to crown fabrication. Materials & Methods: In this cross-sectional study, Easyshade2 device was used to investigate the changes of color. 50 dentistry students were invited to select the color. L, a, b parameters of Vita lumin color samples were measured by Easyshade2 and the differences between them and L, a, b defined in the device memory for the color sample were recorded. Students se-lected the color using Vita lumin color samples. Tooth color was recorded by Easyshade2 and after PFM fabrication, color of FPD was measured by laboratory the results were ana-lyzed using one way ANOVA and student t-test. Results: The mean error of the students compared with the control was about 9. Mean error of the students in comparison with the glaze was 7.6. The maximum cumulative error was re-lated to the student's error with the control (gingival) (ΔE= 14.4) and minimum error was re-lated to the cumulative student error with the glaze (incisal) (ΔE= 5.7). Differences be-tween the students and Easyshade2, Easyshade2 and the glaze or the students and the glaze were statistically significant (P<0.05). Conclusion: There are significant differences between the selected colors of the students, easy-shade2 and color of FPD was fabricated by the laboratory. The maximum cumulative error was related to the selection of color of gingival third by the students compared with the control.