Dynamic fatigue of 3D-printed splint materials.

Johann Wulff, Alois Schmid, Christina Huber, Martin Rosentritt

Journal of the mechanical behavior of biomedical materials 2021 Dec

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Printed splints may be an alternative treatment for functional disorders. In addition to the selection of materials, the influence of cleaning or polymerisation can affect the dynamic behaviour and fatigue limit of printed materials. 96 discs (n = 6 per group, 16mmx2mm) were printed (P30+ DLP-printer, Straumann, CH; 100 μm layer) from splint materials (M1: Luxaprint OrthoPlus, DMG, G; M2: V-Print Splint, Voco, G). Specimens were either automatically cleaned (C1: Straumann P Wash, Straumann, CH) or manually cleaned (C2: Voco Pre-/Main-Clean protocol, Voco, G). Post polymerisation was performed with LED (P1: Cure, Straumann, CH) or Xenon light (P2: Otoflash N171, Ernst Hinrichs Dental, G). The flexural fatigue limit was determined under cyclic loading in terms of a staircase approach with a piston-on-3-ball-test according to ISO 6872 after 24 h or 60 days water storage (37 °C). Specimens were preloaded with 50N and dynamic force was applied for 105 loadings per step (f = 3Hz; steps 1: 50N-100N, 2: 50N-150N, 3: 50N-200N, 4: 50N-250N; F1000, Prematec, G; water at 37 °C). Kaplan Maier Log Rank (Mantel-Cox) test, ANOVA, Pearson correlations, Levene-test (α = 0.05, SPSS 26.0, IBM, Armonk, NY, USA)). Mean survival cycles after 24 h of storage varied between 40388 (M1C2P2) and 195140 (M2C2P1) cycles and after 60 d decreased to 14022 (M1C2P2) and 173237 (M2C1P1). Kaplan Maier Log Rank test revealed significant differences between the material combinations. For M1 cleaning (Pearson: 0.346, p = 0.016) and for M2 polymerisation (Pearson: 0.616, p = 0.000) significantly influenced the number of loading cycles. Intermediate effects were found for material (p = 0.026), cleaning (p = 0.024) and polymerisation (p = 0.000) as well as the combination of material and polymerisation (p = 0.008). The results show that the number of possible loading cycles of additively manufactured splint specimens depends on the type of material, their cleaning and post-polymerisation. Materials, cleaning and post-polymerisation of additive manufacturing processes should be matched to improve dynamic loading performance of splint materials. Copyright © 2021 Elsevier Ltd. All rights reserved.

Citation

Johann Wulff, Alois Schmid, Christina Huber, Martin Rosentritt. Dynamic fatigue of 3D-printed splint materials. Journal of the mechanical behavior of biomedical materials. 2021 Dec;124:104885