Effect of post-rinsing time on the mechanical strength and cytotoxicity of a 3D printed orthodontic splint material

[Display omitted] •Promising SLA-printed acrylic resin for orthodontic applications.•The effect of post-rinsing time on flexural strength and cytotoxicity was studied.•Post-rinsing may induce marked alterations in surface microstructure.•Flexural strength may decrease with increasing post-rinsing ti...

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Bibliographic Details
Published in:Dental materials 2021-05, Vol.37 (5), p.e314-e327
Main Authors: Xu, Yichen, Xepapadeas, Alexander B., Koos, Bernd, Geis-Gerstorfer, Jürgen, Li, Ping, Spintzyk, Sebastian
Format: Article
Language:English
Subjects:
3D printing
Additive manufacturing
Bend strength
Biocompatibility
Cell viability
Cholecystokinin
Cytotoxicity
Dentistry
Evaluation
Flexural Strength
Materials Testing
Mechanical properties
Methacrylate
Modulus of rupture in bending
Monomers
Orthodontics
Printing, Three-Dimensional
Rinsing
Scanning electron microscopy
Splints
Stereolithography
Surface Properties
Three dimensional printing
Toxicity testing
Vat photopolymerization
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Summary:[Display omitted] •Promising SLA-printed acrylic resin for orthodontic applications.•The effect of post-rinsing time on flexural strength and cytotoxicity was studied.•Post-rinsing may induce marked alterations in surface microstructure.•Flexural strength may decrease with increasing post-rinsing time.•Cytocompatibility was significantly improved after post-processing. Since the post-rinsing time is inconsistently recommended, this study aims to investigate the effect of post-rinsing time on the flexural strength and cytotoxicity of an stereolithographically (SLA) printed orthodontic splint material. SLA-printed specimens were ultrasonically rinsed with isopropanol (IPA) for 5 min, 12 min, 20 min, 30 min, 1 h, and 12 h, respectively. Surface characterization was conducted by scanning electron microscopy and roughness measurements. Flexural strength was evaluated using a three-point bending test. Cytotoxicity was determined by direct contact test and extract test. For both tests, cell viability (live/dead staining) and cell metabolic activity (CCK-8 assay) were evaluated. Additionally, water sorption and water solubility were tested to analyze the mass loss from immersion. No apparent surface alterations could be detected on the samples post-rinsed for less than 1 h. In contrast, when the post-rinsing time was prolonged to 12 h, surface fissures could be observed. Flexural strength linearly decreased with increasing post-rinsing time. All post-processed specimens did not show an obvious cytotoxic effect. The removal of cytotoxic methacrylate monomers by post-rinsing with IPA could be achieved in 5 min. Extending post-rinsing time could not improve the cytocompatibility of the SLA-printed orthodontic splint material, and may result in a decrease in flexural strength.
ISSN:0109-5641
1879-0097
DOI:10.1016/j.dental.2021.01.016