Fracture load of 3D-printed fixed dental prostheses compared with milled and conventionally fabricated ones: the impact of resin material, build direction, post-curing, and artificial aging-an in vitro study

Marcel Reymus; Rosalie Fabritius; Andreas Keßler; Reinhard Hickel; Daniel Edelhoff; Bogna Stawarczyk

doi:10.1007/s00784-019-02952-7

Fracture load of 3D-printed fixed dental prostheses compared with milled and conventionally fabricated ones: the impact of resin material, build direction, post-curing, and artificial aging-an in vitro study

Clin Oral Investig. 2020 Feb;24(2):701-710. doi: 10.1007/s00784-019-02952-7. Epub 2019 May 24.

Authors

Marcel Reymus¹, Rosalie Fabritius², Andreas Keßler³, Reinhard Hickel³, Daniel Edelhoff², Bogna Stawarczyk²

Affiliations

¹ Department of Conservative Dentistry and Periodontology, University Hospital, LMU Munich, Goethestrasse 70, 80336, Munich, Germany. mreymus@dent.med.uni-muenchen.de.
² Department of Prosthetic Dentistry, University Hospital, LMU Munich, Goethestrasse 70, 80336, Munich, Germany.
³ Department of Conservative Dentistry and Periodontology, University Hospital, LMU Munich, Goethestrasse 70, 80336, Munich, Germany.

PMID: 31127429
DOI: 10.1007/s00784-019-02952-7

Abstract

Objective: To investigate the impact of 3D print material, build direction, post-curing, and artificial aging on fracture load of fixed dental prostheses (FDPs).

Materials and methods: Three-unit FDPs were 3D-printed using experimental resin (EXP), NextDent C&B (CB), Freeprint temp (FT), and 3Delta temp (DT). In the first part, the impacts of build direction and artificial aging were tested. FDPs were manufactured with their long-axis positioned either occlusal, buccal, or distal to the printer's platform. Fracture load was measured after artificial aging (H₂O: 21 days, 37 °C). In the second part, the impact of post-curing was tested. FDPs were post-cured using Labolight DUO, Otoflash G171, and LC-3DPrint Box. While the positive control group was milled from TelioCAD (TC), the negative control group was fabricated from a conventional interim material Luxatemp (LT). The measured initial fracture loads were compared with those after artificial aging. Each subgroup contained 15 specimens. Data were analyzed using Kolmogorov-Smirnov test, one-way ANOVA followed by Scheffé post hoc test, t test, Kruskal-Wallis test, and Mann-Whitney U test (p < 0.05). The univariate ANOVA with partial eta squared (η_P²) was used to analyze the impact of test parameters on fracture load.

Results: Specimens manufactured with their long-axis positioned distal to the printer's platform showed higher fracture load than occlusal ones (p = 0.049). The highest values were observed for CB, followed by DT (p < 0.001). EXP showed the lowest values, followed by FT (p < 0.001). After artificial aging, a decrease of fracture load for EXP (p < 0.001) and DT (p < 0.001) was observed. The highest impact on values was exerted by interactions between 3D print material and post-curing unit (η_P² = 0.233, p < 0.001), followed by the 3D print material (η_P² = 0.219, p < 0.001) and curing device (η_P² = 0.108, p < 0.001).

Conclusions: Build direction, post-curing, artificial aging, and material have an impact on the mechanical stability of printed FDPs.

Clinical relevance: The correct post-curing strategy is mandatory to ensure mechanical stability of 3D-printed FDPs. Additively manufactured FDPs are more prone to artificial aging than conventionally fabricated ones.

Keywords: 3D printing; Artificial aging; Build direction; Fracture load; Post-curing.

MeSH terms

Dental Materials*
Dental Prosthesis*
Dental Restoration Failure
Dental Stress Analysis
Materials Testing
Printing, Three-Dimensional

Substances

Dental Materials