Does Printing Orientation Matter? In-Vitro Fracture Strength of Temporary Fixed Dental Prostheses after a 1-Year Simulation in the Artificial Mouth

Abstract

Computer-aided design and computer-aided manufacturing (CAD–CAM) enable subtractive or additive fabrication of temporary fixed dental prostheses (FDPs). The present in-vitro study aimed to compare the fracture resistance of both milled and additive manufactured three-unit FDPs and bar-shaped, ISO-conform specimens. Polymethylmethacrylate was used for subtractive manufacturing and a light-curing resin for additive manufacturing. Three (bars) and four (FDPs) different printing orientations were evaluated. All bars (n = 32) were subjected to a three-point bending test after 24 h of water storage. Half of the 80 FDPs were dynamically loaded (250,000 cycles, 98 N) with simultaneous hydrothermal cycling. Non-aged (n = 40) and surviving FDPs (n = 11) were subjected to static loading until fracture. Regarding the bar-shaped specimens, the milled group showed the highest flexural strength (114 ± 10 MPa, p = 0.001), followed by the vertically printed group (97 ± 10 MPa, p < 0.007). Subtractive manufactured FDPs revealed the highest fracture strength (1060 ± 89 N) with all specimens surviving dynamic loading. During artificial aging, 29 of 32 printed specimens failed. The present findings indicate that both printing orientation and aging affect the strength of additive manufactured specimens. The used resin and settings cannot be recommended for additive manufacturing of long-term temporary three-unit FDPs.

Analysis of compressive strength of occlusal splints manufactured with three liquid resins at three angles of orientation on 3D printer

“…Studies show that the orientation of printing influences strength and mechanical properties. Some of these studies show larger strength values for the vertical orientation (Väyrynen et al, 2016;Kebler et al, 2021;Nold et al, 2021). The present study showed that the orientation of 45 degrees of manufacture of occlusal splints with the Cosmos Splint resin increased the compressive strength in comparison with 0 degree; the splints manufactured at 90 degrees showed no significant difference from other orientations in terms of compressive strength.…”

Use Recognizable Digital twin in Virtual Measurement for General Both Evaluation of Additive & Subtractive Manufacturing Process

“…Unconventional processing techniques are different from conventional processing techniques because they use alternative types of energy (such as thermal energy, electrical energy, and chemical energy) to form or remove materials. In 2021，Julian Nold, Christian Wesemann, Laura Rieg, Lara Binder, Siegbert Witkowski, Benedikt Christopher Spies and Ralf Joachim Kohal [10] Unconventional machining processes can replace the original types of energy, such as thermal, electrical and chemical energy to form or remove material, and the fracture resistance of ISO-compliant specimens is used in additive manufacturing.…”

Biochemical Interaction between Materials Used for Interim Prosthetic Restorations and Saliva

“…Certain aspects concerning the conventional and modern materials used for manufacturing interim prosthetic restorations represent important topics in present-day scientific research: the dimensional accuracy and mechanical behavior (compression strength, flexural strength, tensile strength, and wear resistance) [ 4 , 5 , 6 , 7 , 8 , 9 ]; color stability and reparability [ 10 , 11 , 12 ]; and chemical composition and biocompatibility issues (such as cytotoxicity, the materials’ interactions with oral epithelial cells, fibroblasts or dental pulp cells monomer release bacterial adhesion, biofilm formation, antimicrobial activity, and the materials’ interactions with saliva) [ 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 ]. With regard to biocompatibility, the results of various tests performed on saliva samples can contribute to establishing a diagnosis in diverse local or systemic diseases and to monitoring physiological or pathological conditions.…”