Mechanical properties of 3D-printed and milled composite resins for definitive restorationsPrause, Elisabeth (Avtor) Malgaj, Tine (Avtor) Kocjan, Andraž (Avtor) Beuer, Florian (Avtor) Hey, Jeremias (Avtor) Jevnikar, Peter (Avtor) Schmidt, Franziska (Avtor) 3D-printed composite resinsWeibulladditive manufacturingflexural fatigue strengthflexural strengthmilled composite resinsstaircase approachObjective: To evaluate the flexural strength and fatigue behavior of a novel 3D-printed composite resin for definitive restorations. Materials and Methods: Fifty disc-shaped specimens were manufactured from each of a nanohybrid composite resin (NHC), polymer-infiltrated ceramic network (PICN), and 3D-printed composite resin (3D) with CAD-CAM technology. Biaxial flexural strength (σ$_{in}$) (n = 30 per group) and biaxial flexural fatigue strength (σ$_{ff}$) (n = 20 per group) were measured using piston-on-three-balls method, employing a staircase approach of 105 cycles. Weibull statistics, relative-strength degradation calculations, and fractography were performed. The results were analyzed with 1-way ANOVA and Games-Howell post hoc test (α = 0.05). Results: Significant differences in σ$_{in}$ and σ$_{ff}$ among the groups (p < 0.001) were detected. The NHC group provided the highest mean ± standard deviation σ$_{in}$ and σ$_{ff}$ (237.3 ± 31.6 MPa and 141.3 ± 3.8 MPa), followed by the PICN (140.3 ± 12.9 MPa and 73.5 ± 9.9 MPa) and the 3D (83.6 ± 18.5 MPa and 37.4 ± 23.8 MPa) groups. The 3D group exhibited significantly lower Weibull modulus (m = 4.7) and up to 15% higher relative strength degradation with areas of nonhomogeneous microstructure as possible fracture origins. Conclusions: The 3D-printed composite resin exhibited the lowest mechanical properties, where areas of nonhomogeneous microstructure developed during the mixing procedure served as potential fracture origins.20242024-01-24 13:34:10Članek v reviji154085UDK: 616.31ISSN pri članku: 1708-8240DOI: 10.1111/jerd.13132COBISS_ID: 163917571sl