Background: This study aimed to determine the effect of repeated pre-polymerization
heating on the color and translucency of a one-shaded resin-based composite and to evaluate whether
the heating cycles affect its color stability. (2) Methods: Fifty-six samples of 1-mm thickness were
fabricated from Omnichroma (OM) after applying different heating cycles (for one, five, and ten
times at 45 C) before polymerization (n = 14/group) and afterwards were stained with a yellow
dye solution. CIE L*, a*, b*, C*, h coordinates were recorded, and color differences, whiteness, and
translucency were calculated, before and after staining. (3) Results: Heating cycles significantly
influenced the color coordinates, WID00, and TP00 of OM being higher after one heating cycle and
decreasing as the number of heating cycles increased. The color coordinates, WID, and TP00 after
staining significantly differed for each group. The color and whiteness differences calculated after
staining exceeded the acceptability thresholds for all groups. The color and whiteness variations after
staining were clinically unacceptable. (4) Conclusions: Repeated pre-polymerization heating induces
a clinically acceptable color and translucency change to OM. Although the color changes resulting
after staining are clinically unacceptable, increasing the number of heating cycles up to ten times
slightly reduces the color differences.Research Project PCD 1032/55 from the Iuliu Hatieganu University
of Medicine and Pharmacy, Cluj-Napoca, Romani
