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Dai J, Luo K, Liu Q, Unkovskiy A, Spintzyk S, Xu S, Li P. Post-processing of a 3D-printed denture base polymer: Impact of a centrifugation method on the surface characteristics, flexural properties, and cytotoxicity. J Dent 2024; 147:105102. [PMID: 38852693 DOI: 10.1016/j.jdent.2024.105102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2023] [Revised: 05/22/2024] [Accepted: 05/24/2024] [Indexed: 06/11/2024] Open
Abstract
OBJECTIVES To investigate the impact of a centrifugation method on the surface characteristics, flexural properties, and cytotoxicity of an additively manufactured denture base polymer. METHODS The tested specimens were prepared by digital light processing (DLP). A centrifugation method (CENT) was used to remove the residual uncured resin. In addition, the specimens were post-processed with different post-rinsing solutions: isopropanol (IPA), ethanol (EtOH), and tripropylene glycol monomethyl ether (TPM), respectively. A commercial heat-polymerized polymethyl methacrylate was used as a reference (REF). First, the values of surface topography, arithmetical mean height (Sa), and root mean square height (Sq) were measured. Next, flexural strength (FS) and modulus were evaluated. Finally, cytotoxicity was assessed using an extract test. The data were statistically analyzed using a one-way analysis of variance, followed by Tukey's multiple comparison test for post-hoc analysis. RESULTS The Sa value in the CENT group was lower than in the IPA, EtOH, TPM, and REF groups (p < 0.001). Moreover, the CENT group had lower Sq values than other groups (p < 0.001). The centrifugation method showed a higher FS value (80.92 ± 8.65 MPa) than the EtOH (61.71 ± 12.25 MPa, p < 0.001) and TPM (67.01 ± 9.751 MPa, p = 0.027), while affecting IPA (72.26 ± 8.80 MPa, p = 0.268) and REF (71.39 ± 10.44 MPa, p = 0.231). Also, the centrifugation method showed no evident cytotoxic effects. CONCLUSIONS The surfaces treated with a centrifugation method were relatively smooth. Simultaneously, the flexural strength of denture base polymers was enhanced through centrifugation. Finally, no evident cytotoxic effects could be observed from different post-processing procedures. CLINICAL SIGNIFICANCE The centrifugation method could optimize surface quality and flexural strength of DLP-printed denture base polymers without compromising cytocompatibility, offering an alternative to conventional rinsing post-processing.
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Affiliation(s)
- Jingtao Dai
- Department of Orthodontics, Stomatological Hospital, School of Stomatology, Southern Medical University, South Jiangnan Road No. 366, Guangzhou 510280, China
| | - Ke Luo
- Center of Oral Implantology, Stomatological Hospital, Southern Medical University, South Jiangnan Road No. 366, Guangzhou 510280, China
| | - Qian Liu
- Center of Oral Implantology, Stomatological Hospital, Southern Medical University, South Jiangnan Road No. 366, Guangzhou 510280, China
| | - Alexey Unkovskiy
- Department of Prosthodontics, Geriatric Dentistry and Craniomandibular Disorders, Charité - University Hospital, Aßmannshauser Str. 4-6, Berlin 14197, Germany; Department of Dental Surgery, Sechenov First Moscow State Medical University, Bolshaya Pirogovskaya Street, 19с1, Moscow 119146, Russia
| | - Sebastian Spintzyk
- ADMiRE Lab - Additive Manufacturing, intelligent Robotics, Sensors and Engineering, School of Engineering and IT, Carinthia University of Applied Sciences, Europastraße 4, 9524 Villach, Austria
| | - Shulan Xu
- Center of Oral Implantology, Stomatological Hospital, Southern Medical University, South Jiangnan Road No. 366, Guangzhou 510280, China.
| | - Ping Li
- Department of Prosthodontics, School and Hospital of Stomatology, Guangdong Engineering Research Center of Oral Restoration and Reconstruction, Guangzhou Medical University, Guangzhou, China; Guangzhou Key Laboratory of Basic and Applied Research of Oral Regenerative Medicine, Guangzhou Medical University, Guangzhou, China.
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Kim JE, Mangal U, Yu JH, Kim GT, Kim H, Seo JY, Cha JY, Lee KJ, Kwon JS, Choi SH. Evaluation of the effects of temperature and centrifugation time on elimination of uncured resin from 3D-printed dental aligners. Sci Rep 2024; 14:15206. [PMID: 38956329 PMCID: PMC11219924 DOI: 10.1038/s41598-024-66150-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2024] [Accepted: 06/27/2024] [Indexed: 07/04/2024] Open
Abstract
The study investigated the effects of temperature and centrifugation time on the efficacy of removing uncured resin from 3D-printed clear aligners. Using a photo-polymerizable polyurethane resin (Tera Harz TC-85, Graphy Inc., Seoul, Korea), aligners were printed and subjected to cleaning processes using isopropyl alcohol (IPA) or centrifugation (g-force 27.95g) at room temperature (RT, 23 °C) and high temperature (HT, 55 °C) for 2, 4, and 6 min. The control group received no treatment (NT). Cleaning efficiency was assessed through rheological analysis, weight measurement, transparency evaluation, SEM imaging, 3D geometry evaluation, stress relaxation, and cell viability tests. Results showed increased temperature and longer centrifugation times significantly reduced aligner viscosity, weight (P < 0.05), and transmittance. IPA-cleaned aligners exhibited significantly lower transparency and rougher surfaces in SEM images. All groups met ISO biocompatibility standards in cytotoxicity tests. The NT group had higher root mean square (RMS) values, indicating greater deviation from the original design. Stress relaxation tests revealed over 95% recovery in all groups after 60 min. The findings suggest that a 2-min HT centrifugation process effectively removes uncured resin without significantly impacting the aligners' physical and optical properties, making it a clinically viable option.
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Affiliation(s)
- Ji-Eun Kim
- Department and Research Institute of Dental Biomaterials and Bioengineering, Yonsei University College of Dentistry, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, Republic of Korea
| | - Utkarsh Mangal
- BK21 FOUR Project, Yonsei University College of Dentistry, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, Republic of Korea
| | - Jae-Hun Yu
- BK21 FOUR Project, Yonsei University College of Dentistry, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, Republic of Korea
- Department of Orthodontics, Institute of Craniofacial Deformity, Yonsei University College of Dentistry, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, Republic of Korea
| | - Gi-Tae Kim
- Department and Research Institute of Dental Biomaterials and Bioengineering, Yonsei University College of Dentistry, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, Republic of Korea
- BK21 FOUR Project, Yonsei University College of Dentistry, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, Republic of Korea
| | - Hoon Kim
- Research Institute of Agriculture and Life Sciences, College of Agriculture and Life Sciences, Seoul National University, Seoul, Republic of Korea
| | - Ji-Young Seo
- Department of Orthodontics, Institute of Craniofacial Deformity, Yonsei University College of Dentistry, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, Republic of Korea
| | - Jung-Yul Cha
- Department of Orthodontics, Institute of Craniofacial Deformity, Yonsei University College of Dentistry, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, Republic of Korea
| | - Kee-Joon Lee
- Department of Orthodontics, Institute of Craniofacial Deformity, Yonsei University College of Dentistry, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, Republic of Korea
| | - Jae-Sung Kwon
- Department and Research Institute of Dental Biomaterials and Bioengineering, Yonsei University College of Dentistry, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, Republic of Korea.
- BK21 FOUR Project, Yonsei University College of Dentistry, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, Republic of Korea.
| | - Sung-Hwan Choi
- Department of Orthodontics, Institute of Craniofacial Deformity, Yonsei University College of Dentistry, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, Republic of Korea.
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Katheng A, Prawatvatchara W, Tonprasong W, Namano S, Kongkon P. Effect of Postrinsing Times and Methods on Surface Roughness, Hardness, and Polymerization of 3D-Printed Photopolymer Resin. Eur J Dent 2024. [PMID: 38759997 DOI: 10.1055/s-0044-1786866] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/19/2024] Open
Abstract
OBJECTIVES This in vitro study investigated the effects of different postrinsing times and methods on the surface roughness, surface hardness, and degree of polymerization of materials manufactured via stereolithography (SLA). MATERIALS AND METHODS A total of 288 disk-shaped specimens were manufactured using an SLA three-dimensional (3D) printer. The specimens were randomly divided into nine groups (n = 32) based on rinsing times and methods. The groups were categorized into three rinsing methods: automated, ultrasonic, and hand washing, with rinsing times of 5, 10, and 15 minutes using a 99% isopropanol alcohol as a solvent. Linear roughness (Ra) and area roughness (Sa) were measured using a 3D confocal laser microscopy; the roughness morphology was evaluated by using scanning electron microscopy. Vickers hardness (VHN) tests were performed using a Vickers microhardness tester. Fourier-transform infrared spectrometry was used to determine the degree of conversion of treated specimens. STATISTICAL ANALYSIS Data were statistically analyzed using two-way analysis of variance. The post hoc Tukey tests were conducted to compare the differences between groups (p < 0.05). RESULTS The choice of the rinsing time and method affected the surface properties of the SLA photopolymer resin. The 15 minutes of ultrasonic method exhibited the highest Ra scores (0.86 ± 0.1 µm), while the 15 minutes of automated method presented the highest Sa scores (1.77 ± 0.35 µm). For the VHN test, the 15 minutes of ultrasonic method displayed the highest VHN score (18.26 ± 1.03 kgf/mm2). For the degree of polymerization, the 15 minutes of automated method was initially identified as the most effective (87.22 ± 6.80). CONCLUSION To facilitate the overall surface roughness, surface hardness, and degree of polymerization, the optimal choice of postprocessing rinsing time and method for achieving a clear photopolymer resin was determined to be the ultrasonic method with a rinsing time of 15 minutes.
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Affiliation(s)
- Awutsadaporn Katheng
- Department of Restorative Dentistry, Faculty of Dentistry, Naresuan University, Phitsanulok, Thailand
| | - Wisarut Prawatvatchara
- Department of Prosthodontics, Faculty of Dentistry, Chulalongkorn University, Bangkok, Thailand
| | - Watcharapong Tonprasong
- Department of Restorative Dentistry, Faculty of Dentistry, Naresuan University, Phitsanulok, Thailand
| | - Sahaprom Namano
- Department of Gerodontology and Oral Rehabilitation, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Paweena Kongkon
- Department of Restorative Dentistry, Faculty of Dentistry, Naresuan University, Phitsanulok, Thailand
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Finck NS, Fraga MAA, Correr AB, Dalmaschio CJ, Rodrigues CS, Moraes RR. Effects of solvent type and UV post-cure time on 3D-printed restorative polymers. Dent Mater 2024; 40:451-457. [PMID: 38129193 DOI: 10.1016/j.dental.2023.12.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Revised: 12/04/2023] [Accepted: 12/08/2023] [Indexed: 12/23/2023]
Abstract
OBJECTIVES This study evaluated the impact of different solvents and UV post-curing times on properties of 3D printing resins for provisional restorations. METHODS The post-processing methods were tested using two solvents (isopropyl alcohol or absolute ethanol) and three UV times (5, 10, or 30 min). The resins tested were Resilab 3D Temp, Printax Temp, and Prizma Bioprov. Microhardness (kgf/mm2), fracture toughness (KIC, MPa√m), surface roughness (Ra, µm), gloss (gloss units), and degree of CC conversion (%DC) were measured (n = 8). All response variables were collected from the same specimen. The specimens were 3D printed using an SLA/LCD printer (150° angulation, 50 µm layer thickness). Light exposure times were adjusted for each material, and the post-processing methods were applied using an all-in-one machine immediately after printing. Data were analyzed using Three-Way ANOVA (α = 0.05). RESULTS Microhardness was affected by UV post-cure time and 3D resin. Resilab showed higher microhardness with isopropyl alcohol and 30-min UV time, while Printax had higher microhardness with absolute ethanol. KIC was influenced by solvent type, UV time, and 3D resin, with varying effects on different resins. Roughness was affected by 3D resin and UV time, but no significant differences were seen for Resilab or Prizma. Gloss was influenced by 3D resin, and for Prizma, it was lower with specific solvent/UV time combinations. DC was influenced by 3D resin, with each resin behaving differently. SIGNIFICANCE Tailoring the combination of 3D resin, solvent washing type, and UV post-curing time is important to achieve optimal mechanical and aesthetic outcomes for restorations.
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Affiliation(s)
- Nathalia S Finck
- School of Dentistry, Centro Universitário FAESA, Vitória, Brazil; Graduate Program in Dentistry, Universidade Federal de Pelotas, Pelotas, Brazil
| | - May Anny A Fraga
- Department of Restorative Dentistry, Dental Materials Division, Piracicaba Dental School, State University of Campinas, Piracicaba, Brazil
| | - Américo B Correr
- Department of Restorative Dentistry, Dental Materials Division, Piracicaba Dental School, State University of Campinas, Piracicaba, Brazil
| | - Cleocir J Dalmaschio
- Department of Chemistry, Universidade Federal do Espírito Santo, Vitória, Brazil
| | - Camila S Rodrigues
- Graduate Program in Dentistry, Universidade Federal de Pelotas, Pelotas, Brazil
| | - Rafael R Moraes
- Graduate Program in Dentistry, Universidade Federal de Pelotas, Pelotas, Brazil.
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Zenthöfer A, Ilani A, Schmitt C, Rammelsberg P, Hetzler S, Rues S. Biaxial flexural strength of 3D-printed 3Y-TZP zirconia using a novel ceramic printer. Clin Oral Investig 2024; 28:145. [PMID: 38351386 PMCID: PMC10864574 DOI: 10.1007/s00784-024-05533-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Accepted: 01/29/2024] [Indexed: 02/16/2024]
Abstract
OBJECTIVES To compare the strength and reliability of 3D-printed 3Y-TZP zirconia manufactured with various printing orientations and staining. MATERIALS AND METHODS A total of one-hundred cylindrical zirconia specimens were designed and fabricated using 3D printing and processed according to ISO 6872 standards. Of these specimens, 80 were 3D printed using the new ZIPRO-D (ZD) 3D ceramic printer. In this ZD group, 60 specimens were printed in a vertical orientation and were either stained after debinding (ZD1, x-orientation, n = 20) or not stained (ZD2, x-orientation, n = 20; ZD3, y-orientation, n = 20) and the remaining 20 specimens out of n = 80 were printed in a horizontal orientation (ZD4). Further 20 specimens out of the entire sample N = 100 were printed vertically with the CeraFab7500 3D ceramic printer (LC). All completed specimens were loaded until fracture using a universal testing machine. Biaxial flexural strengths and Weibull parameters were computed for the ZD groups and for the LC group. Group and sub-group effects were evaluated using Welch ANOVA (alpha = 0.05). RESULTS The mean (standard deviation, SD) biaxial flexural strengths of vertically oriented ZD samples with (ZD1) and without (ZD2/ZD3) staining were 811 (197) and 850 (152) MPa, respectively (p > 0.05). The ZD4 (horizontally printed), 1107 (144) MPa, and LC (1238 (327)) MPa samples had higher mean (SD) flexural strengths than the ZD1-3 specimens. No difference was observed between the ZD4 and LC group (p > 0.05). Weibull moduli were between m = 4.6 (ZD1) and 9.1 (ZD4) in the ZD group and m = 3.5 in the LC group. CONCLUSIONS All tested 3D-printed zirconia specimens exceeded the flexural strengths required for class 5 restorations according to ISO 6872 standards. While the flexural strengths of zirconia printed using the novel ZD device in the vertical orientation are lower than those of zirconia printed using the LC printer, the ZD printer shows at least comparable reliability. CLINICAL RELEVANCE 3D-printing of zirconia is a new technology in dental application. Based on the presented strengths values, clinical application of 3D-printed zirconia for fixed dental protheses can be recommended.
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Affiliation(s)
- Andreas Zenthöfer
- Department of Prosthodontics, University Clinic Heidelberg, University of Heidelberg, 69120, Heidelberg, Germany.
| | - Ali Ilani
- Department of Prosthodontics, University Clinic Heidelberg, University of Heidelberg, 69120, Heidelberg, Germany
| | - Clemens Schmitt
- Department of Prosthodontics, University Clinic Heidelberg, University of Heidelberg, 69120, Heidelberg, Germany
| | - Peter Rammelsberg
- Department of Prosthodontics, University Clinic Heidelberg, University of Heidelberg, 69120, Heidelberg, Germany
| | - Sebastian Hetzler
- Department of Prosthodontics, University Clinic Heidelberg, University of Heidelberg, 69120, Heidelberg, Germany
| | - Stefan Rues
- Department of Prosthodontics, University Clinic Heidelberg, University of Heidelberg, 69120, Heidelberg, Germany
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Li P, Fernandez PK, Spintzyk S, Schmidt F, Yassine J, Beuer F, Unkovskiy A. Effects of layer thickness and build angle on the microbial adhesion of denture base polymers manufactured by digital light processing. J Prosthodont Res 2023; 67:562-567. [PMID: 36804247 DOI: 10.2186/jpr.jpr_d_22_00126] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
Abstract
PURPOSE To investigate the effects of printing-layer thickness and build angle on the surface characteristics and microbial adhesion of denture base polymers manufactured by digital light processing (DLP). METHODS Specimens were additively manufactured using DLP. The specimens were printed with different printing-layer thicknesses (25, 50, and 100 μm) and build angles (0°, 45°, and 90°). Scanning electron microscopy was used to observe the surface topography, and the arithmetical mean heights (Sa) were measured. Moreover, the initial Candida albicans (C. albicans) adhesion to the specimens was evaluated using an adhesion test. Finally, two-way ANOVA and Tukey's multiple comparison tests were conducted. RESULTS The results regarding the Sa values exhibited a statistically significant interaction (F (4, 45) = 90.77, P < 0.0001). The build angle has a significant impact on the surface topography. Furthermore, quantitative results revealed that the printing-layer thickness significantly affected C. albicans adhesion (F (2, 99) = 6.96, P = 0.0015). CONCLUSIONS The surface roughness was significantly affected by the printing-layer thickness and the build angle. Additionally, the surface topography was mainly determined by the build angle. Furthermore, the adhesion of C. albicans to the DLP-printed denture surfaces was significantly affected by the printing-layer thickness but not by the build angle. Consequently, it is critical to decrease the thickness of the printing layer to produce digital dentures with optimal material properties.
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Affiliation(s)
- Ping Li
- Center of Oral Implantology, Stomatological Hospital, School of Stomatology, Southern Medical University, Guangzhou, China
- Section Medical Materials Science and Technology, Tübingen University Hospital, Tübingen, Germany
| | - Pablo Kraemer Fernandez
- Department of Prosthodontics at the Centre of Dentistry, Oral Medicine and Maxillofacial Surgery with Dental School, Tübingen University Hospital, Tübingen, Germany
| | - Sebastian Spintzyk
- Section Medical Materials Science and Technology, Tübingen University Hospital, Tübingen, Germany
- ADMiRE Lab - Additive Manufacturing, intelligent Robotics, Sensors and Engineering, School of Engineering and IT, Carinthia University of Applied Sciences, Villach, Austria
| | - Franziska Schmidt
- Department of Prosthodontics, Geriatric Dentistry and Craniomandibular Disorders, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Jamila Yassine
- Department of Prosthodontics, Geriatric Dentistry and Craniomandibular Disorders, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Florian Beuer
- Department of Prosthodontics, Geriatric Dentistry and Craniomandibular Disorders, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
| | - Alexey Unkovskiy
- Department of Prosthodontics, Geriatric Dentistry and Craniomandibular Disorders, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, Berlin, Germany
- Department of Dental Surgery, Sechenov First Moscow State Medical University, Moscow, Russia
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Liebermann A, Schultheis A, Faber F, Rammelsberg P, Rues S, Schwindling FS. Impact of post printing cleaning methods on geometry, transmission, roughness parameters, and flexural strength of 3D-printed zirconia. Dent Mater 2023; 39:625-633. [PMID: 37179237 DOI: 10.1016/j.dental.2023.05.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2023] [Revised: 04/12/2023] [Accepted: 05/02/2023] [Indexed: 05/15/2023]
Abstract
OBJECTIVE To analyze the impact of different post printing cleaning methods on geometry, transmission, roughness parameters, and flexural strength of additively manufactured zirconia. METHODS Disc-shaped specimens (N = 100) were 3D-printed from 3 mol%-yttria-stabilized zirconia (material: LithaCon 3Y 210; printer: CeraFab 7500, Lithoz) and were cleaned with five different methods (n = 20): (A) 25 s of airbrushing with the dedicated cleaning solution (LithaSol 30®, Lithoz) and 1-week storage in a drying oven (40 °C); (B) 25 s airbrushing (LithaSol 30®) without drying oven; (C) 30 s ultrasonic bath (US) filled with Lithasol30®; (D) 300 s US filled with LithaSol 30®; (E) 30 s US filled with LithaSol 30® followed by 40 s of airbrushing (LithaSol 30®). After cleaning, the samples were sintered. Geometry, transmission, roughness (Ra, Rz), characteristic strengths (σ0), and Weibull moduli (m) were analyzed. Statistical analyses were performed using Kolmogorov-Smirnov-, t-, Kruskal-Wallis-, and Mann-Whitney-U-tests (α < 0.05). RESULTS Short US (C) resulted in the thickest and widest samples. Highest transmission was found for US combined with airbrushing (E, p ≤ 0.004), followed by D and B (same range, p = 0.070). Roughness was lowest for US combined with airbrushing (E, p ≤ 0.039), followed by A and B (same range, p = 0.172). A (σ0 = 1030 MPa, m = 8.2), B (σ0 = 1165 MPa, m = 9.8), and E (σ0 = 1146 MPa, m = 8.3) were significantly stronger (p < 0.001) and substantially more reliable than C (σ0 = 480 MPa, m = 1.9) and D (σ0 = 486 MPa, m = 2.1). SIGNIFICANCE For 3D-printed zirconia, cleaning strategy selection is important. Airbrushing (B) and short US combined with airbrushing (E) were most favorable regarding transmission, roughness, and strength. Ultrasonic cleaning alone was ineffective (short duration) or detrimental (long duration). Strategy E could be particularly promising for hollow or porous structures.
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Affiliation(s)
- A Liebermann
- Department of Prosthetic Dentistry, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany.
| | - A Schultheis
- Department of Prosthetic Dentistry, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
| | - F Faber
- Department of Prosthetic Dentistry, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
| | - P Rammelsberg
- Department of Prosthetic Dentistry, Heidelberg University Hospital, Heidelberg, Germany
| | - S Rues
- Department of Prosthetic Dentistry, Heidelberg University Hospital, Heidelberg, Germany
| | - F S Schwindling
- Department of Prosthetic Dentistry, Heidelberg University Hospital, Heidelberg, Germany; Department of Prosthetic Dentistry, Medical University Innsbruck, Innsbruck, Austria
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Influence of the Printing Orientation on Parallelism, Distance, and Wall Thickness of Adjacent Cylinders of 3D-Printed Surgical Guides. PROSTHESIS 2023. [DOI: 10.3390/prosthesis5010023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/18/2023]
Abstract
This in-vitro study aimed to evaluate the influence of the printing orientation on parallelism, distance, and thickness between adjacent cylinders of 3D-printed surgical guides. CAD software was used to design a surgical guide with two adjacent parallel cylinders (reference); the design was saved as standard tessellation software (STL) and 63 samples were printed using three different orientations (0, 45, and 90 degrees). A metrology digital microscope was used to measure the distance, the angle and the thickness of the guides cylinders. Afterwards, the printed guides were scanned and cloud comparison software was used to compare STL files from the printed guides against the reference CAD model. One-way analysis of variance and Tukey test were used for multiple comparisons between groups and significance was p < 0.05. The printing orientation affected the distance between cylinders, the parallelism and the wall thickness. In addition, there were global deviations in all printing orientations. Printing with 90 degrees orientation produced almost-parallel cylinders but walls thicker than the reference model; all the cylinders converged toward the coronal but printing at 0 degrees produced the closest distance to the reference value. Within the limitations of this experimental in-vitro study it can be concluded that all the printing orientations influence the angle, the distance, and the thickness between adjacent cylinders of a surgical guide. Printing at 90 degrees produces the best global correspondence with the master model.
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Goracci C, Juloski J, D’Amico C, Balestra D, Volpe A, Juloski J, Vichi A. Clinically Relevant Properties of 3D Printable Materials for Intraoral Use in Orthodontics: A Critical Review of the Literature. MATERIALS (BASEL, SWITZERLAND) 2023; 16:ma16062166. [PMID: 36984045 PMCID: PMC10058724 DOI: 10.3390/ma16062166] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 03/01/2023] [Accepted: 03/07/2023] [Indexed: 06/05/2023]
Abstract
The review aimed at analyzing the evidence available on 3D printable materials and techniques used for the fabrication of orthodontic appliances, focusing on materials properties that are clinically relevant. MEDLINE/PubMed, Scopus, and Cochrane Library databases were searched. Starting from an initial retrieval of 669 citations, 47 articles were finally included in the qualitative review. Several articles presented proof-of-concept clinical cases describing the digital workflow to manufacture a variety of appliances. Clinical studies other than these case reports are not available. The fabrication of aligners is the most investigated application of 3D printing in orthodontics, and, among materials, Dental LT Clear Resin (Formlabs) has been tested in several studies, although Tera Harz TC-85 (Graphy) is currently the only material specifically marketed for direct printing of aligners. Tests of the mechanical properties of aligners materials lacked homogeneity in the protocols, while biocompatibility tests failed to assess the influence of intraoral conditions on eluents release. The aesthetic properties of 3D-printed appliances are largely unexplored. The evidence on 3D-printed metallic appliances is also limited. The scientific evidence on 3D printable orthodontic materials and techniques should be strengthened by defining international standards for laboratory testing and by starting the necessary clinical trials.
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Affiliation(s)
- Cecilia Goracci
- Department of Medical Biotechnologies, University of Siena, 53100 Siena, Italy
| | - Jovana Juloski
- Department of Orthodontics, School of Dental Medicine, University of Belgrade, 11000 Belgrade, Serbia
| | - Claudio D’Amico
- Department of Medical Biotechnologies, University of Siena, 53100 Siena, Italy
| | - Dario Balestra
- School of Dental Medicine, Alfonso X El Sabio University, 28691 Madrid, Spain
| | - Alessandra Volpe
- Department of Medical Biotechnologies, University of Siena, 53100 Siena, Italy
| | - Jelena Juloski
- Department of Medical Biotechnologies, University of Siena, 53100 Siena, Italy
- Clinic for Paediatric and Preventive Dentistry, School of Dental Medicine, University of Belgrade, 11000 Belgrade, Serbia
| | - Alessandro Vichi
- Dental Academy, University of Portsmouth, Portsmouth PO1 2QG, UK
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Song S, Zhang J, Liu M, Li F, Bai S. Effect of build orientation and layer thickness on manufacturing accuracy, printing time, and material consumption of 3D printed complete denture bases. J Dent 2023; 130:104435. [PMID: 36693587 DOI: 10.1016/j.jdent.2023.104435] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 01/13/2023] [Accepted: 01/20/2023] [Indexed: 01/22/2023] Open
Abstract
OBJECTIVES To evaluate the influence of build orientation and layer thickness on manufacturing accuracy, material consumption, and printing time of complete denture (CD) bases fabricated using digital light processing (DLP). METHODS The CD base was designed on the basis of a standard maxillary edentulous model. Seventy CD bases were fabricated using a DLP 3D printer (Pro95, SprintRay, USA) and printable CD base material (DENTCA Denture Base II, Dentca, USA) at seven build orientations (0°, labial 45°, labial 90°, posterior 45°, posterior 90°, buccal 45°, and buccal 90°) and two types of layer thicknesses (50- and 100 μm) (n = 5). All test CD bases were digitalized and superimposed on the reference cast by section-based best-fit alignment. For evaluating manufacturing accuracy, deviation analysis was performed to compare the test data with the reference cast using the "3D Compare" in the 3D metrology software. The printing time and material consumption were calculated using slicing software and recorded, respectively. The two-way ANOVA test was used for accuracy evaluation, and the non-parametric test was used to evaluate printing time and material consumption (α = 0.05). RESULTS Statistically significant differences were found in the manufacturing accuracy (p < 0.001), printing time (p < 0.001), and material consumption (p < 0.001) among the build orientation groups. The labial 45° and labial 90° groups showed the best accuracy. The 90° build orientations required the least material consumption and longest printing time; the labial 45° group consumed the most printing materials; the 0° group required the shortest printing time to fabricate a CD base. Moreover, the layer thickness influenced the printing time (p < 0.001) rather than the accuracy (p = 0.560) and material consumption (p = 1.000). CONCLUSIONS When DLP was used to fabricate the CD bases, the build orientation influenced the manufacturing accuracy, material consumption, and printing time. However, the layer thickness only affected the printing time. CLINICAL SIGNIFICANCE This study suggests that optimizing the build orientation can improve the manufacturing accuracy and reduce the material consumption and printing time of a DLP-printed CD base. The fast-printing setting (100 μm layer thickness) can reduce the printing time without compromising the manufacturing accuracy of the CD base.
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Affiliation(s)
- Shiwei Song
- State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Key Laboratory of Stomatology, Digital Center, School of Stomatology, The Fourth Military Medical University, Xi'an, Shaanxi 710012, China; School of Stomatology, Shanxi Medical University, 56 Xinjian South Road, Taiyuan, Shanxi, China
| | - Jie Zhang
- State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Key Laboratory of Stomatology, Digital Center, School of Stomatology, The Fourth Military Medical University, Xi'an, Shaanxi 710012, China; School of Stomatology, Shanxi Medical University, 56 Xinjian South Road, Taiyuan, Shanxi, China
| | - Miao Liu
- State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Key Laboratory of Stomatology, Digital Center, School of Stomatology, The Fourth Military Medical University, Xi'an, Shaanxi 710012, China; School of Stomatology, Shanxi Medical University, 56 Xinjian South Road, Taiyuan, Shanxi, China
| | - Fenglan Li
- Department of Prosthodontics, Fifth Hospital of Shanxi Medical University, Taiyuan, Shanxi, China.
| | - Shizhu Bai
- State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Key Laboratory of Stomatology, Digital Center, School of Stomatology, The Fourth Military Medical University, Xi'an, Shaanxi 710012, China.
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Post-processing of DLP-printed denture base polymer: Impact of a protective coating on the surface characteristics, flexural properties, cytotoxicity, and microbial adhesion. Dent Mater 2022; 38:2062-2072. [DOI: 10.1016/j.dental.2022.11.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Revised: 10/26/2022] [Accepted: 11/11/2022] [Indexed: 11/27/2022]
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Analysis of the Deflection, Bristle Splaying, and Abrasion of a Single Tuft of a Polybutylene Terephthalate Toothbrush after Use: A Randomized Controlled Trial. MATERIALS 2022; 15:ma15144890. [PMID: 35888356 PMCID: PMC9320165 DOI: 10.3390/ma15144890] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Revised: 07/11/2022] [Accepted: 07/12/2022] [Indexed: 12/07/2022]
Abstract
The aim of this study is to clarify the deflection, splaying, and abrasion of single tufts of polybutylene terephthalate (PBT) toothbrushes after use. A single-center randomized controlled trial is performed. The changes in deflection, bristle splaying, and abrasion are investigated for the middle single tuft of the top line (top–middle tuft) and the middle single tuft of the bottom line (bottom–middle tuft) of PBT toothbrushes with medium stiffness after 1 month, 2 months, and 3 months of use by 34 participants. A soft-material bending-resistance tester is used to assess the deflection of the single tufts. The deflection value of the top–middle tuft significantly increased after 1 month of use compared with the baseline. In contrast, the deflection of the bottom–middle tuft significantly increased after 3 months of use compared with the baseline and after 1 month and 2 months of use. Importantly, the change in deflection was distinctly different between the top– and bottom–middle tufts. The bristle splaying of both tufts significantly increased after use, but a significant change in bristle abrasion was not found. The bending stiffness of the top tuft of a PBT toothbrush may decrease more rapidly than that of the bottom tuft with use.
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