Effects of UV Postcuring Times on the Color Stability, Surface Properties and Conversion of 3D-printed Temporary Resin Composites.

ABSTRACT

OBJECTIVE: To evaluate the effects of UV postcuring times on color stability (CS), surface properties (wettability [°] and surface roughness [Ra]), and conversion of 3D-printed resins for temporary restorations. METHODS: Disc-shaped specimens (10.0×3.0 mm) and maxillary central incisors (8.2×10.3 mm) were fabricated using provisional 3D-printed resin (PriZma Bio Prov [PZ] and PrintaX AA TEMP [PX]) in A2 shade and subjected to UV postcure times of 0 (T0), 5 (T1), 10 (T2), and 15 (T3) minutes (n=15). The incisors were used for CS evaluation with a colorimeter. In contrast, discs were used to measure the contact angle using the sessile drop method, surface roughness with an optical profilometer, and degree of conversion with FT-NIR. For CS, Ra, contact angle, and degree of conversion, a two-way ANOVA with Bonferroni post-hoc test (α=0.05) was used. RESULTS: PX resin demonstrated greater color stability than PZ (p=0.001). Long UV postcuring times (10 to 15 minutes) will increase the contact angle (p=0.013) and stabilize the degree of conversion (p=0.01), while 5 to 10 minutes of UV postcuring will provide better surface smoothness (p=0.04) of both resins. CONCLUSIONS: Long UV postcuring times (10 to 15 minutes) lead to greater alterations in color, contact angle, and stability of the degree of conversion, while 5 to 10 minutes lead to a smoother surface of the 3D-printed temporary resins.