Color stability, surface roughness and flexural strength of additively manufactured and milled interim restorative materials after aging

To evaluate the effect of two different additive manufacturing technologies on the color stability, surface roughness and biaxial flexural strength of interim restorative materials after thermal aging. Disk-shaped specimens were manufactured via two types of vat polymerization methods [Stereo-lithography (SLA) and digital light processing (DLP)] and milling technology (n = 16). CIELab color coordinates and surface roughness were measured before and after thermal cycling. Then biaxial flexural strength tests were performed using a universal testing machine. The data were analyzed by Kruskal–Wallis, one-way ANOVA, and Tamhane and Tukey HSD tests (α < 0.05). There was no significant difference among ΔE values of all study groups (p = 0.191). The milled group showed a higher initial surface roughness value (p < 0.05), while there was no significant difference among the other groups after aging (p = 0.213). DLP had significantly lower flexural strength values than SLA and Milled (p = 0.000). After aging, SLA and DLP were similar to milling method, in terms of color stability and surface roughness. However, milling had an adverse effect on the initial surface roughness. The SLA and milled groups had better mechanical properties than the DLP group.