Evaluation of a 3D-printed nanohybrid resin composite versus a milled resin composite for flexural strength, wear and color stability

Abstract

Background: Controversial properties and performance of commercially available 3D-printed resin composite for permanent restorations. So, the purpose of this study was to assess the flexural strength, microhardness, wear, and color stability of 3D-printed versus milled nanohybrid resin composites for permanent restoration. Methods: A total of 70 samples of nanohybrid resin composites were used; 38 bar-shaped (14 mm ⋅ 2 mm ⋅ 2 mm) and 32 disc-shaped samples (10 mm ⋅ 2 mm) of Tetric CAD^™ blocks (TC) and Flexcera Smile Ultra plus^™ (FSU) were fabricated (n = 35). Flexural properties were tested using 3-point bending test. The Vickers test was used for microhardness evaluation. Volumetric wear analysis and color changes were assessed after simulated aging via Geomagic Control X software and a Vita Easyshade spectrophotometer, respectively. Color changes were calculated via the CIEDE2000 formula. A paired t-test was used for dependent variable analysis, and the Mann‒Whitney U test was used for independent variables (α = 0.05). Results: TC resulted in significantly higher flexural strength (247.7 ± 29.1 MPa) and microhardness (94.6 ± 3 gf/um²) than did FSU (97.2 ± 10.2 MPa and 31 ± 4.6 gf/um^2, respectively) (P < 0.0001). Compared with FSU (–36.3 mm³), TC resulted in significantly lower wear rates (–17.6 mm³)(P < 0.0001). TC had a ΔE00 value of 2.4 ± 0.5, whereas FSU had a value of 2.1 ± 0.7 (P = 0.532), with no significant difference between the groups, but both values were above the acceptability limit (1.8). Conclusions: Compared with 3D-printed nanohybrid resin composites, milled nanohybrid resin composites have better flexural strength, microhardness and wear properties. Clinical relevance: Milled nanohybrid resin composites exhibit superior flexural strength, microhardness, and wear resistance, making them potentially more durable for clinical dental restorations compared to 3D-printed nanohybrid resin composites.