# Color Differences of Polimerized Resin-Based Composites and Corresponding Shade Guides
## 4 Discussion
All the other results for the composites fell into the \"extremely unacceptable\" range. The composite Empress(r) showed the highest \(\Delta\)E00 values for all three colors, with \(\Delta\)E00 = 11.8 for the color A2, \(\Delta\)E00 = 13.1 for the color A3, and \(\Delta\)E00 = 10.8 for the color A3.5. The Empress(r) composite was the most distant from the VITAPAN Classical(r) shade guide. The color differences obtained showed a weak correlation between the composites studied and the color guide, according to previous studies [31; 51]. These differences may be related to the manufacturing material or the curved geometry of the color guide samples. These factors could influence the reflection of light, varying the color measurements of the spectrophotometer. Taking into account the CIEDE2000 values recorded between the studied composites and their respective color guides, it was demonstrated that the Harmonize(r) composite resembled the VITAPAN Classical(r) shade guide more closely than its own color guide. However, the Empress(r) composite in all its colors and the Vocco(r) composite for the colors A2 and A3 showed colors that were closer to their respective color guides. The latter composite displayed the same CIEDE2000 value (\(\Delta\)E00 = 3.5) for the color A3.5 concerning both the VITAPAN Classical(r) shade guide and its own color guide, making it equally similar or dissimilar to both guides. Vocco(r) was the composite that presented the smallest color differences in relation to its respective color guide. These differences may be due to the manufacturing material of their own guides, the thickness of the samples or their geometry. Taking into consideration the study by [PERSON] et al. (2019) [50] and the CIEDE2000 values obtained between the composite samples and their respective color guides, the color differences for the Vocco(r) composite for the colors A2 (\(\Delta\)E00 = 3.5), A3 (\(\Delta\)E00 = 2.3) and A3.5 (\(\Delta\)E00 = 3.5) should be considered \"moderately unacceptable\"; the Empress(r) composite for the color A2 (\(\Delta\)E00 = 7.4) should be thought of as \"clearly unacceptable\"; last of all, the Harmonize(r) composite for the colors A2 (\(\Delta\)E00 = 12.6) and A3 (\(\Delta\)E00 = 11.3), as well as the Empress(r) composite for the colors A3 (\(\Delta\)E00 = 7.4) and A3.5 (\(\Delta\)E00 = 6.8), should be deemed \"extremely unacceptable\". Considering the results obtained from comparing the color samples of the studied composites with their own color guides and the VITAPAN Classical(r) color guide, it can be concluded that the color register can be established interchangeably with both guides as there were no statistically significant differences. However, when CIEDE2000 values were analyzed, which indicated the distance between colors, the composite colors were closer to their respective color guides than to the VITAPAN Classical(r) color guide. Our study highlights the need for more sophisticated color selection methods, such as color determination via spectrophotometry. We agree with [PERSON] et al. (2021) about all of the color guides used yielding unacceptable results and also with [PERSON] et al. (2022) that it is necessary to improve commercially available dental shade guides [18; 52]. The color measuring devices are especially useful for reducing subjective variables inherent in visual methods. Devices like spectrophotometers (e.g., Vita Easyshade) present high ICC and ROC values in vitro which validate their indication as color diagnostic tools [36]. Furthermore, it is necessary in clinical settings to control related effective factors or conditions to perform optimally [34; 53]. Relative to tooth color observed in the population, shade guides do not provide a full range of choices, making clinical shade selection difficult. However, composite shade guides that do not match their purported color standards make this already difficult task even more difficult.