2023 Volume 3 Issue 1 Pages 43-51
Purpose: This study aimed to evaluate the influence of 37°C water immersion for up to 180 days on the discoloration of conventional resin composite cements and self-adhesive resin cements.
Methods: Three conventional resin cements (Panavia V5, RelyX Ultimate, and Variolink Esthetic DC) and three self-adhesive resin cements (SA Luting Cement, RelyX Unicem 2, and SpeedCEM Plus) were examined in this study. Disk specimens (⌀15.0×1.0 mm) were fabricated using the cements and their colors were measured (CIELAB). The specimens were immersed in distilled water at 37°C for 180 days and the colors were repeatedly measured at 1, 7, 14, 21, 28, 90, and 180 days. The color differences (ΔE) were calculated for each measurement period. In addition, water sorption, water solubility, and surface free energy of the cements were measured. Data were analyzed using the Shapiro-Wilk test, Friedman’s test and Bonferroni corrections, and Mann-Whitney U-test.
Results: All the cements except SA Luting Cement revealed clinically acceptable values of ΔE (＜3.3) at 90 days of immersion. ΔE of the cements remarkably increased after 90 days and showed values much greater than 3.3 at 180 days. All the self-adhesive resin cements demonstrated significantly greater values of water sorption than the corresponding conventional resin composite cements. As for water solubility, one of the three comparison pairs (Panavia V5 and SA Luting Cement) did not show a significant difference. The surface free energy was similar among the cements at approximately 50 mJ/m2.
Conclusions: Although the water sorption of the resin cements increased due to the presence of the adhesive monomers, the discoloration did not intensify as water absorption increased. The degree of discoloration was not related to the degree of water sorption.
