*2.3. Cell Viability Assay*

We evaluated the cytotoxic effects of the four calcium silicate-based cements using a methyl-thiazoldiphenyl-tetrazolium (MTT) assay (MTT Cell Growth Assay Kit; Chemicon, Rosemont, IL, USA) [25,26]. The proliferation rate of the GDSCs was analyzed after 0, 1, 2, 3, and 5 days of culture growth. GDSCs were seeded at a density of 1.0 <sup>×</sup> 104 cells/well on 24-well cell culture plates (SPL Life Sciences, Pocheon, Korea) with a growth medium. After 24 h of culture for cell attachment, we obtained the optical density value for day 0. An individual disk was stored in an insert with a 0.4 μm pore size (SPLInsert; SPL Life Sciences) and the insert was stored over the GDSCs. For maintaining the medium level up to the disk, each well was supplemented with an extra 1 mL of growth medium. GDSCs cultured without experimental disks were used as positive controls, and IRM was used as a negative control. MTT solution at a concentration of 500 μg/mL was added to each well for 4 h. Thereafter, each well was washed with PBS and dimethyl sulfoxide was added to dissolve the synthesized formazan. The optical density at 570 nm was determined using an absorbance microplate reader (Power Wave XS; BioTek Instruments, Winooski, VT, USA) with the absorbance at 630 nm as the reference. Each group was evaluated in quadruplicate.

#### *2.4. Cell Migration Assay*

We evaluated cell migratory ability using a scratch wound healing assay. GDSCs were seeded at a density of 3.5 <sup>×</sup> <sup>10</sup><sup>4</sup> cells/well on 24-well cell culture plates (SPL Life Sciences, Pocheon, Korea) with a growth medium. After 24 h of culture, a scratch wound was created in the middle of the confluent cell layer using a 1000 μL pipette tip. After scratching, cell debris was rinsed off with PBS. After 24 h of culture, each individual disk was stored in an insert with a 0.4 μm pore size (SPLInsert; SPL Life Sciences) and the insert was stored over the GDSCs. For maintaining the medium level up to the disk, each well was supplemented with an extra 1 mL of growth medium. GDSCs with various calcium silicate-based cement disks were incubated for 4 days, with changing the medium every 2 days. Images of wound healing were observed at 0, 1, 2, 3, and 4 days using a phase-contrast microscope (Olympus, Tokyo, Japan). ImageJ 1.46r (National Institutes of Health, Bethesda, MD, USA) was used to determine

the wound healing area. We calculated the area of cell migration into the wound using the initial wound area as the reference. Each group was evaluated in quadruplicate.
