The effects of preheating on color values of polyacid-modified composite resins

Objectives: Color stability is crucial to the esthetic success of restorative materials. Internal and external factors affect the coloring of these materials. Research carried out on the development of restorative materials draws attention to the advantages of methods such as preheating resins, reducing the viscosity and light cure time, increasing the marginal adaptation, and increasing the degree of monomer conversion. The aim of this study was to examine the in vitro effects of preheating polyacid-modified composite resins (PMCRs) on their color values and evaluate the obtained findings comparatively. Materials and Methods: Four main groups were formed by preparing discs from A2-colored PMCR material, which were kept at four different temperatures (4°C, 23°C, 39°C, and 55°C) before polymerization. The colors of the discs were measured according to the Commission on Illumination Laboratory system before and after they were kept in distilled water for 24 hours. The data were statistically analyzed using IBM Statistical Package for the Social Sciences V3. Results: It was seen that the preheating treatment did not significantly affect the color sensation (∆E) and red-green (∆a) color values of the PMCRs. It was determined that this process was effective on the lightness (∆L) and blue-yellow (∆b) color values of the materials. Conclusion: It should be considered that preheating applied to PMCRs may be beneficial for the longevity of the color stability of restorations, but different oral hygiene and dietary habits may have different effects on PMCRs.