The Influence of Modeling Liquid on Microhardness of Single-Shade Composite Resins: An In-Vitro Study.

Aim: To assess the effect of modeling liquid on the microhardness of single-shade universal composites.

Materials and methods: A total of 60 disk-shaped samples were prepared in six groups [Omnichroma (OM), Essentia Universal (EU), Vittra APS Unique (VA), OM + Signum, EU + Signum, and VA + Signum] for surface microhardness measurements. Samples were stored in a coffee solution for 7 days and after that bleached with an Office bleaching agent (Total Blanc Office). Surface microhardness was measured for baseline, after staining, and after bleaching. A two-way analysis of variance test was used for statistical analysis (P < 0.05).

Results: In terms of microhardness, there is a statistically significant difference (P < 0.05) between the two categories with and without modeling liquid. The alterations in microhardness measurements at baseline, after staining, and after bleaching are statistically significant (P < 0.05). The Essentia groups showed the lowest microhardness findings at all measurement times. Microhardness values decreased significantly more when EU was applied along with modeling liquid than when it was not applied at different intervals.

Conclusions: Modeling liquid affects the microhardness of single-shade composites. Microhardness is reduced when modeling liquid is used for all three single-shade universal composite resins at three different times.