Yichen Xu1, Alexander B Xepapadeas2, Bernd Koos2, Jürgen Geis-Gerstorfer3, Ping Li4, Sebastian Spintzyk3. 1. State Key Laboratory of Oral Diseases and National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, Sichuan, China; Department of Oral Prosthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, Sichuan, China; University Hospital Tübingen, Section Medical Materials Science and Technology, Osianderstrasse 2-8, Tübingen 72076, Germany. 2. Department of Orthodontics, University Hospital Tübingen, Osianderstrasse 2-8, Tübingen 72076, Germany. 3. University Hospital Tübingen, Section Medical Materials Science and Technology, Osianderstrasse 2-8, Tübingen 72076, Germany. 4. University Hospital Tübingen, Section Medical Materials Science and Technology, Osianderstrasse 2-8, Tübingen 72076, Germany. Electronic address: ping.li@uni-tuebingen.de.
Abstract
OBJECTIVE: 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. METHODS: 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. RESULTS: 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. SIGNIFICANCE: 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.
OBJECTIVE: 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. METHODS: 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. RESULTS: 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. SIGNIFICANCE: 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.
Authors: Tamas Hegedus; Patrik Kreuter; Aron Attila Kismarczi-Antalffy; Tamas Demeter; Dorottya Banyai; Adam Vegh; Zoltan Geczi; Peter Hermann; Michael Payer; Akos Zsembery; Ahmad Al-Hassiny; Khaled Mukaddam; Valentin Herber; Norbert Jakse; Daniel Vegh Journal: Int J Environ Res Public Health Date: 2022-02-09 Impact factor: 3.390