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Souza LFB, Teixeira KF, Cadore-Rodrigues AC, Pires TDS, Valandro LF, Moraes RR, Özcan M, Pereira GKR. Evaluating mechanical and surface properties of zirconia-containing composites: 3D printing, subtractive, and layering techniques. J Mech Behav Biomed Mater 2024; 157:106608. [PMID: 38833781 DOI: 10.1016/j.jmbbm.2024.106608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2024] [Revised: 05/01/2024] [Accepted: 05/29/2024] [Indexed: 06/06/2024]
Abstract
This study assessed the monotonic and fatigue flexural strength (FS), elastic modulus (E), and surface characteristics of a 3D printed zirconia-containing resin composite compared to subtractive and conventional layering methods. Specimens, including discs (n = 15; Ø = 15 mm × 1.2 mm) and bars (n = 15; 14 × 4 × 1.2 mm), were prepared and categorized into three groups: 3D printing (3D printing - PriZma 3D Bio Crown, Makertech), Subtractive (Lava Ultimate blocks, 3M), and Layering (Filtek Z350 XT, 3M). Monotonic tests were performed on the discs using a piston-on-three-balls setup, while fatigue tests employed similar parameters with a frequency of 10 Hz, initial stress at 20 MPa, and stress increments every 5000 cycles. The E was determined through three-point-bending test using bars. Surface roughness, fractographic, and topographic analyses were conducted. Statistical analyses included One-way ANOVA for monotonic FS and roughness, Kruskal-Wallis for E, and Kaplan-Meier with post-hoc Mantel-Cox and Weibull analysis for fatigue strength. Results revealed higher monotonic strength in the Subtractive group compared to 3D printing (p = 0.02) and Layering (p = 0.04), while 3D Printing and Layering exhibited similarities (p = 0.88). Fatigue data indicated significant differences across all groups (3D Printing < Layering < Subtractive; p = 0.00 and p = 0.04, respectively). Mechanical reliability was comparable across groups. 3D printing and Subtractive demonstrated similar E, both surpassing Layering. Moreover, 3D printing exhibited higher surface roughness than Subtractive and Layering (p < 0.05). Fractographic analysis indicated that fractures initiated at surface defects located in the area subjected to tensile stress concentration. A porous surface was observed in the 3D Printing group and a more compact surface in Subtractive and Layering methods. This study distinguishes the unique properties of 3D printed resin when compared to conventional layering and subtractive methods for resin-based materials. 3D printed shows comparable monotonic strength to layering but lags behind in fatigue strength, with subtractive resin demonstrating superior performance. Both 3D printed and subtractive exhibit similar elastic moduli, surpassing layering. However, 3D printed resin displays higher surface roughness compared to subtractive and layering methods. The study suggests a need for improvement in the mechanical performance of 3D printed material.
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Affiliation(s)
- Luiza Freitas Brum Souza
- MSciD and PhD Post-Graduate Program in Oral Science, Faculty of Dentistry, Federal University of Santa Maria (UFSM), Santa Maria, Rio Grande do Sul State, Brazil.
| | - Kétlin Fagundes Teixeira
- MSciD and PhD Post-Graduate Program in Oral Science, Faculty of Dentistry, Federal University of Santa Maria (UFSM), Santa Maria, Rio Grande do Sul State, Brazil.
| | - Ana Carolina Cadore-Rodrigues
- MSciD and PhD Post-Graduate Program in Oral Science, Faculty of Dentistry, Federal University of Santa Maria (UFSM), Santa Maria, Rio Grande do Sul State, Brazil.
| | - Telma de Souza Pires
- Faculty of Dentistry, Federal University of Santa Maria (UFSM), Santa Maria, Rio Grande do Sul State, Brazil.
| | - Luiz Felipe Valandro
- MSciD and PhD Post-Graduate Program in Oral Science, Faculty of Dentistry, Federal University of Santa Maria (UFSM), Santa Maria, Rio Grande do Sul State, Brazil; Faculty of Dentistry, Federal University of Santa Maria (UFSM), Santa Maria, Rio Grande do Sul State, Brazil.
| | - Rafael R Moraes
- School of Dentistry, Universidade Federal de Pelotas, Pelotas, RS, Brazil.
| | - Mutlu Özcan
- Clinic for Masticatory Disorders and Dental Biomaterials, Center for Dental Medicine, University of Zurich, 8032, Zurich, Switzerland.
| | - Gabriel Kalil Rocha Pereira
- MSciD and PhD Post-Graduate Program in Oral Science, Faculty of Dentistry, Federal University of Santa Maria (UFSM), Santa Maria, Rio Grande do Sul State, Brazil; Faculty of Dentistry, Federal University of Santa Maria (UFSM), Santa Maria, Rio Grande do Sul State, Brazil.
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Liu Y, Jin G, Lim JH, Kim JE. Effects of washing agents on the mechanical and biocompatibility properties of water-washable 3D printing crown and bridge resin. Sci Rep 2024; 14:9909. [PMID: 38688952 PMCID: PMC11061276 DOI: 10.1038/s41598-024-60450-7] [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: 11/01/2023] [Accepted: 04/23/2024] [Indexed: 05/02/2024] Open
Abstract
Three-dimensional (3D) printing, otherwise known as additive manufacturing in a non-technical context, is becoming increasingly popular in the field of dentistry. As an essential step in the 3D printing process, postwashing with organic solvents can damage the printed resin polymer and possibly pose a risk to human health. The development of water-washable dental resins means that water can be used as a washing agent. However, the effects of washing agents and washing times on the mechanical and biocompatibility properties of water-washable resins remain unclear. This study investigated the impact of different washing agents (water, detergent, and alcohol) and washing time points (5, 10, 20, and 30 min) on the flexural strength, Vickers hardness, surface characterization, degree of conversion, biocompatibility, and monomer elution of 3D printed samples. Using water for long-term washing better preserved the mechanical properties, caused a smooth surface, and improved the degree of conversion, with 20 min of washing with water achieving the same biological performance as organic solvents. Water is an applicable agent option for washing the 3D printing water-washable temporary crown and bridge resin in the postwashing process. This advancement facilitates the development of other water-washable intraoral resins and the optimization of clinical standard washing guidelines.
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Affiliation(s)
- Yunqi Liu
- Department of Prosthodontics, College of Dentistry, Yonsei University, Yonsei-ro 50-1, Seodaemun-gu, Seoul, 03722, Republic of Korea
| | - Gan Jin
- Department of Prosthodontics, College of Dentistry, Yonsei University, Yonsei-ro 50-1, Seodaemun-gu, Seoul, 03722, Republic of Korea
| | - Jung-Hwa Lim
- Department of Prosthodontics, College of Dentistry, Yonsei University, Yonsei-ro 50-1, Seodaemun-gu, Seoul, 03722, Republic of Korea
| | - Jong-Eun Kim
- Department of Prosthodontics, College of Dentistry, Yonsei University, Yonsei-ro 50-1, Seodaemun-gu, Seoul, 03722, Republic of Korea.
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Nam NE, Hwangbo NK, Kim JE. Effects of surface glazing on the mechanical and biological properties of 3D printed permanent dental resin materials. J Prosthodont Res 2024; 68:273-282. [PMID: 37245959 DOI: 10.2186/jpr.jpr_d_22_00261] [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] [Indexed: 05/30/2023]
Abstract
Purpose This study aimed to determine the surface glazing effect on the mechanical and biological properties of three-dimensional printed dental permanent resins.Methods Specimens were prepared using Formlabs, Graphy Tera Harz permanent, and NextDent C&B temporary crown resins. Specimens were divided into three groups: samples with untreated surfaces, glazed surfaces, and sand-glazed surfaces. The flexural strength, Vickers hardness, color stability, and surface roughness of the samples were analyzed to identify their mechanical properties. Their cell viability and protein adsorption were analyzed to identify their biological properties.Results The flexural strength and Vickers hardness of the samples with sand glazed and glazed surfaces were significantly increased. The color change was higher for surface untreated samples than that for the samples with sand-glazed and glazed surfaces. The surface roughness of the samples with sand-glazed and glazed surfaces was low. The samples with sand-glazed and glazed surfaces have low protein adsorption ability and high cell viability.Conclusions Surface glazing increased the mechanical strength, color stability, and cell compatibility, while reducing the Ra and protein adsorption of 3D-printed dental resins. Thus, a glazed surface exhibited a positive effect on the mechanical and biological properties of 3D-printed resins.
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Affiliation(s)
- Na-Eun Nam
- Department of Prosthodontics, Yonsei University College of Dentistry, Seoul, Korea
| | - Na-Kyung Hwangbo
- Department of Orofacial Pain and Oral Medicine, Yonsei University College of Dentistry, Seoul, Korea
| | - Jong-Eun Kim
- Department of Prosthodontics, Yonsei University College of Dentistry, Seoul, Korea
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Espinar C, Pérez MM, Pulgar R, Leon-Cecilla A, López-López MT, Della Bona A. Influence of printing orientation on mechanical properties of aged 3D-printed restorative resins. Dent Mater 2024; 40:756-763. [PMID: 38429216 DOI: 10.1016/j.dental.2024.02.023] [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: 07/19/2023] [Revised: 02/15/2024] [Accepted: 02/18/2024] [Indexed: 03/03/2024]
Abstract
OBJECTIVE To evaluate the influence of printing orientation on flexural strength (σf) and elastic modulus (E) of different 3D printing dental restorative resins. METHODS Bar-shaped specimens (n = 20) were fabricated from two SLA-printed resins (FT- Formlabs Temporary, and FP- Formlabs Permanent) and two DLP-printed resins (DFT- Detax Freeprint Temp, and GCT- GC Temporary) using two building orientations (0º and 90º). The 3D-printed structures were aged (14 d) before submitted to three-point bending in 37ºC distilled water at a crosshead speed of 1.0 ± 0.3 mm/min until fracture to calculate the σf and the E values. The fractured surfaces were evaluated using stereomicroscopy and scanning electron microscopy (SEM) following fractography principles. Data were statistically analyzed using two-way ANOVA and Tukey post-hoc (α = 0.001). RESULTS FP and FT showed significantly higher E values than DFT and GCT, irrespectively of printing orientation (p < 0.001). There was no statistical difference between the building orientations (0º and 90º) for the mean σf and E values for the resin materials evaluated. Fractographic characteristics were similar for the surface fracture from all the materials evaluated, showing typical brittle fracture behavior. SIGNIFICANCE Printing orientation did not influence of flexural strength and elastic modulus values for the 3D-printed resin structures evaluated. Surface topography was mostly governed by the 3D printer type.
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Affiliation(s)
- Cristina Espinar
- Department of Stomatology, Faculty of Dentistry, Colegio Máximo, Campus de Cartuja s/n. University of Granada, 18071 Granada, Spain
| | - María M Pérez
- Department of Optics, Faculty of Science, Campus Fuentenueva, Edificio Mecenas, s/n. University of Granada, 18071 Granada, Spain
| | - Rosa Pulgar
- Department of Stomatology, Faculty of Dentistry, Colegio Máximo, Campus de Cartuja s/n. University of Granada, 18071 Granada, Spain
| | - Alberto Leon-Cecilla
- Department of Applied physics, Faculty of Science, Campus Fuentenueva, University of Granada, 18071 Granada, Spain
| | - Modesto T López-López
- Department of Applied physics, Faculty of Science, Campus Fuentenueva, University of Granada, 18071 Granada, Spain
| | - Alvaro Della Bona
- Postgraduate Program in Dentistry, Dental School, University of Passo Fundo, Campus I, Passo Fundo, RS, Brazil.
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Prause E, Malgaj T, Kocjan A, Beuer F, Hey J, Jevnikar P, Schmidt F. Mechanical properties of 3D-printed and milled composite resins for definitive restorations: An in vitro comparison of initial strength and fatigue behavior. J ESTHET RESTOR DENT 2024; 36:391-401. [PMID: 37680013 DOI: 10.1111/jerd.13132] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2023] [Revised: 08/06/2023] [Accepted: 08/25/2023] [Indexed: 09/09/2023]
Abstract
OBJECTIVE To evaluate the flexural strength and fatigue behavior of a novel 3D-printed composite resin for definitive restorations. MATERIALS AND METHODS Fifty disc-shaped specimens were manufactured from each of a nanohybrid composite resin (NHC), polymer-infiltrated ceramic network (PICN), and 3D-printed composite resin (3D) with CAD-CAM technology. Biaxial flexural strength (σin ) (n = 30 per group) and biaxial flexural fatigue strength (σff ) (n = 20 per group) were measured using piston-on-three-balls method, employing a staircase approach of 105 cycles. Weibull statistics, relative-strength degradation calculations, and fractography were performed. The results were analyzed with 1-way ANOVA and Games-Howell post hoc test (α = 0.05). RESULTS Significant differences in σin and σff among the groups (p < 0.001) were detected. The NHC group provided the highest mean ± standard deviation σin and σff (237.3 ± 31.6 MPa and 141.3 ± 3.8 MPa), followed by the PICN (140.3 ± 12.9 MPa and 73.5 ± 9.9 MPa) and the 3D (83.6 ± 18.5 MPa and 37.4 ± 23.8 MPa) groups. The 3D group exhibited significantly lower Weibull modulus (m = 4.7) and up to 15% higher relative strength degradation with areas of nonhomogeneous microstructure as possible fracture origins. CONCLUSIONS The 3D-printed composite resin exhibited the lowest mechanical properties, where areas of nonhomogeneous microstructure developed during the mixing procedure served as potential fracture origins. CLINICAL SIGNIFICANCE The clinical indications of the investigated novel 3D-printed composite resin should be limited to long-term provisional restorations. A cautious procedure for mixing the components is crucial before the 3D-printing process, since nonhomogeneous areas developed during the mixing could act as fracture origins.
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Affiliation(s)
- Elisabeth Prause
- Department of Prosthodontics, Geriatric Dentistry and Craniomandibular Disorders, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Tine Malgaj
- Department of Prosthodontics, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Andraž Kocjan
- Department for Nanostructured Materials, Jožef Stefan Institute, Ljubljana, Slovenia
| | - Florian Beuer
- Department of Prosthodontics, Geriatric Dentistry and Craniomandibular Disorders, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Jeremias Hey
- Department of Prosthodontics, School of Dental Medicine, Martin-Luther-University, Halle, Germany
| | - Peter Jevnikar
- Department of Prosthodontics, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Franziska Schmidt
- Department of Prosthodontics, Geriatric Dentistry and Craniomandibular Disorders, Charité-Universitätsmedizin Berlin, Berlin, Germany
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Cao J, Liu X, Cameron A, Aarts J, Choi JJE. Influence of different post-processing methods on the dimensional accuracy of 3D-printed photopolymers for dental crown applications - A systematic review. J Mech Behav Biomed Mater 2024; 150:106314. [PMID: 38113824 DOI: 10.1016/j.jmbbm.2023.106314] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2023] [Revised: 12/05/2023] [Accepted: 12/07/2023] [Indexed: 12/21/2023]
Abstract
OBJECTIVES To perform a systematic review that provides an overview of the current literature on the influence of different post-processing methods on the accuracy of additive-manufactured (3D-printed) photopolymer crown materials, and whether more research is needed. MATERIALS AND METHODS The search used three online databases, Ovid (MEDLINE), Scopus and Web of Science which were screen for publications that involved assessing dimensional accuracy in post-processing of 3D printed dental crown materials. Publications that were literature reviews, abstracts, written in a language different from English, or publications that did not assess dimensional accuracy were excluded. RESULTS The included articles were published between 1995 and 2023. After the removal of duplicates using Endnote, 135 studies remained for further screening, 13 were selected for full-text analysis, and 7 studies were included in the systematic review. A total of 7 articles were examined and categorised based on several factors, such as the type of material, number of specimens per group, print layer thickness, print angle of specimens, 3D printer used, properties of the specimens studied, and the method of analysing the accuracy of the specimens. CONCLUSION It was found that post-processing washing times outside the prescribed instruction for use (IFU) may have an impact on the physical and biocompatibility characteristics of the material. Studies focusing on inert mediums during post-processing require more detailed investigation. The use of different post-curing conditions does not significantly affect the materials dimensional accuracy.
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Affiliation(s)
- Jason Cao
- Sir John Walsh Research Institute, Faculty of Dentistry, University of Otago, New Zealand
| | - Xiaoyun Liu
- Sir John Walsh Research Institute, Faculty of Dentistry, University of Otago, New Zealand
| | - Andrew Cameron
- School of Medicine and Dentistry, Griffith University, Australia; Member Centre of Biomedical and Rehabilitation Engineering, Menzies Health Institute Queensland, Australia
| | - John Aarts
- Sir John Walsh Research Institute, Faculty of Dentistry, University of Otago, New Zealand
| | - Joanne Jung Eun Choi
- Sir John Walsh Research Institute, Faculty of Dentistry, University of Otago, New Zealand.
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Prause E, Hannak WB, Nicic R, Jakstat HA, Böning K, Klinke T. Visual Versus Digital Color Determination of 3D-Printed Teeth as an Exercise in Dental Students' Education. Dent J (Basel) 2024; 12:24. [PMID: 38392228 PMCID: PMC10888070 DOI: 10.3390/dj12020024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Revised: 01/05/2024] [Accepted: 01/22/2024] [Indexed: 02/24/2024] Open
Abstract
Visual color determination is part of the daily routine in dental practice. However, it is not a part of dental education so far. The aim of this study was to evaluate whether visual or digital tooth color determination of 3D-printed teeth is a reliable tool for inexperienced dentistry students. Preclinical dental students evaluated eleven 3D-printed, tooth-shaped samples (VarseoSmile Crown plus, BEGO, Bremen, Germany) of different color shades. Visual shade determination using a reference scale (3D-Master Toothguide (3DM_TG), VITA Zahnfabrik, Bad Säckingen, Germany), followed by a digital color determination using a spectrophotometer (VITA Easyshade V, (ES_V), VITA Zahnfabrik), was performed. Color deviation was calculated in the Lab* color space (ΔE00) and converted into CIELAB 2000. The results were evaluated using the Mann-Whitney U test and the Wilcoxon Rank Sum test (α = 0.05). Significant differences between visual and digital color determination were proven (p < 0.001). Visual color determination (3DM_TG) showed a mean deviation (ΔE00 ± 95%CI) of 6.49 ± 0.47. Digital color determination (ES_V) showed significantly lower mean deviations of ΔE00 of 1.44 ± 0.58. Digital tooth color measurement using a spectrophotometer was a more reliable tool for the color determination of 3D-printed teeth for inexperienced dentistry students.
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Affiliation(s)
- Elisabeth Prause
- Department of Prosthodontics, Geriatric Dentistry and Craniomandibular Disorders, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, 14197 Berlin, Germany
| | - Wolfgang B Hannak
- Department of Prosthodontics, Geriatric Dentistry and Craniomandibular Disorders, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, 14197 Berlin, Germany
| | - Robert Nicic
- Department of Prosthodontics, Geriatric Dentistry and Craniomandibular Disorders, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, 14197 Berlin, Germany
| | - Holger A Jakstat
- Department of Prosthodontics and Material Science, University of Leipzig, 20251 Leipzig, Germany
| | - Klaus Böning
- Department of Prosthetic Dentistry, Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden, 01069 Dresden, Germany
| | - Thomas Klinke
- Department of Prosthodontics, Gerodontology and Dental Materials, Center of Oral Health, University Medicine Greifswald, 17489 Greifswald, Germany
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Chung SH, Jiang ES, Lim BS, Kim SH, Chang J. Multi-peak Light-emitting Diode Curing Units and Polymerization of 3D-printed Crown and Bridge Resin. Oper Dent 2024; 49:98-109. [PMID: 38058011 DOI: 10.2341/23-061-l] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/05/2023] [Indexed: 12/08/2023]
Abstract
PURPOSE This study aimed to evaluate the substitutive and additive efficacy of multi-peak light-emitting diode (LED) curing units for post-curing of a three-dimensional- (3D-) printed crown and bridge resin. METHODS A total of 792 disc- and 180 bar-shaped specimens were printed with a crown and bridge resin (NextDent C&B MFH) and post-cured using two LED curing units (VALO Cordless and Bluephase N G4) in fast and standard modes. Conventional post-curing (LC-3D Print Box, Group PC) was compared with LED-only curing (Groups V1, V2, B1, and B2) and LED-combined curing (Groups PV1, PV2, PB1, and PB2) in terms of microhardness, flexural strength, degree of conversion (DC), and CIE L*a*b* color and translucency parameters. Cytotoxicity of the resin eluates was evaluated using the WST-1 assay. Temperature increases on the resin surface were measured with infrared thermography. Data were statistically analyzed using ANOVA and Kruskal-Wallis tests (α=0.05). RESULTS The microhardness and flexural strength in Groups V1, V2, B1, and DC in all LED-only groups were lower than in other groups (p<0.05). Larger color disparities existed between Group PC and all LED-only groups than between Group PC and the others (p<0.05). There was no significant difference in cytotoxicity among the groups. The temperature increase was lowest in Groups V1 and PV1 during light curing (p<0.05). CONCLUSIONS Post-curing by multi-peak LED curing units was not as effective as the conventional post-curing device. Additional post-curing by LED curing units did not improve the material properties.
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Affiliation(s)
- S H Chung
- Shin Hye Chung, DDS, MSD, PhD, Department of Dental Biomaterials Science, School of Dentistry and Dental Research Institute, Seoul National University, Seoul, Republic of Korea
| | - E-S Jiang
- En-Shi Jiang, DDS, MSD, PhD, Department of Stomatology, Yanbian University and Affiliated Hospital of Yanbian University, Yanji China
| | - B-S Lim
- Bum-Soon Lim, PhD, Department of Dental Biomaterials Science, School of Dentistry and Dental Research Institute, Seoul National University, Seoul, Republic of Korea
| | - S-H Kim
- Seong-Hae Kim, Center for Future Dentistry, Seoul National University, Seoul, Republic of Korea
| | - J Chang
- *Juhea Chang, DDS, MSD, PhD, National Dental Care Center for Persons with Special Needs, Seoul National University Dental Hospital, Seoul, Republic of Korea
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Lee WJ, Jo YH, Yoon HI. Influence of postpolymerization time and atmosphere on the mechanical properties, degree of conversion, and cytotoxicity of denture bases produced by digital light processing. J Prosthet Dent 2023; 130:265.e1-265.e7. [PMID: 37353410 DOI: 10.1016/j.prosdent.2023.05.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 05/14/2023] [Accepted: 05/16/2023] [Indexed: 06/25/2023]
Abstract
STATEMENT OF PROBLEM Studies on the effects of postprocessing conditions on the physical properties, degree of conversion (DC), and biocompatibility of denture bases produced by digital light processing are lacking. PURPOSE The purpose of this in vitro study was to evaluate the effects of the atmosphere during postpolymerization and of postpolymerization time on the flexural strength, Vickers hardness, DC, cytotoxicity, and residual monomer content of denture bases. MATERIAL AND METHODS Six different groups of bar- and disk-shaped specimens from the denture base resin were produced, considering 2 different atmospheres (air and nitrogen) and 3 different postpolymerization times (5, 10, and 20 minutes). To determine the physical properties, the flexural strength and Vickers hardness were measured. Fourier transform infrared spectrometry was used to calculate DC. Cytotoxicity was assessed from the effect on human gingival fibroblasts. The residual monomer content was determined by using high-performance liquid chromatography. Based on the normality test by the Shapiro-Wilk method, a nonparametric factorial analysis of variances was conducted (α=.05). RESULTS A significant interaction was detected between the atmosphere and postpolymerization time for hardness (P<.001) but no interaction for strength, DC, or cytotoxicity (P=.826, P=.786, and P=.563, respectively). Hardness was significantly affected by the postpolymerization time in the groups with the nitrogen atmosphere (P<.001). DC was significantly affected by the atmosphere (P=.012), whereas strength and cytotoxicity were not (P=.500 and P=.299, respectively). Cytotoxicity was significantly affected by the postpolymerization time (P<.001), but strength and DC were not (P=.482 and P=.167, respectively). Residual monomers were not detected after ≥10-minute postpolymerization time. CONCLUSIONS The atmosphere significantly affected hardness and DC, whereas the postpolymerization time significantly affected hardness, DC, cytotoxicity, and residual monomer content. Denture bases produced in a nitrogen atmosphere and with the 10-minute postpolymerization time showed sufficient hardness, DC, and no cytotoxicity.
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Affiliation(s)
- Won-Jun Lee
- Graduate student, Department of Prosthodontics, School of Dentistry and Dental Research Institute, Seoul National University, Seoul, Republic of Korea
| | - Ye-Hyeon Jo
- Senior Researcher, Dental Research Institute, Seoul National University School of Dentistry, Seoul, Republic of Korea
| | - Hyung-In Yoon
- Associate Professor, Department of Prosthodontics, School of Dentistry and Dental Research Institute, Seoul National University, Seoul, Republic of Korea; Adjunct Professor, Department of Reconstructive Dentistry and Gerodontology, School of Dental Medicine, University of Bern, Bern, Switzerland.
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10
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Oh R, Lim JH, Lee CG, Lee KW, Kim SY, Kim JE. Effects of washing solution temperature on the biocompatibility and mechanical properties of 3D-Printed dental resin material. J Mech Behav Biomed Mater 2023; 143:105906. [PMID: 37178635 DOI: 10.1016/j.jmbbm.2023.105906] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Revised: 05/07/2023] [Accepted: 05/08/2023] [Indexed: 05/15/2023]
Abstract
The use of digital manufacturing, particularly additive manufacturing using three-dimensional (3D) printing, is expanding in the field of dentistry. 3D-printed resin appliances must undergo an essential process, post-washing, to remove residual monomers; however, the effect of the washing solution temperature on the biocompatibility and mechanical properties remains unclear. Therefore, we processed 3D-printed resin samples under different post-washing temperatures (without temperature control (N/T), 30 °C, 40 °C, and 50 °C) for different durations (5, 10, 15, 30, and 60 min) and evaluated the degree of conversion rate, cell viability, flexural strength, and Vickers hardness. Increasing the washing solution temperature significantly improved the degree of conversion rate and cell viability. Conversely, increasing the solution temperature and time decreased the flexural strength and microhardness. This study confirmed that the washing temperature and time influence the mechanical and biological properties of the 3D-printed resin. Washing 3D-printed resin at 30 °C for 30 min was most efficient to maintain optimal biocompatibility and minimize changes of mechanical properties.
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Affiliation(s)
- Rojee Oh
- Dental Hospital, Veterans Health Service Medical Center, Seoul, 05368, Republic of Korea; Department of Prosthodontics, Yonsei University College of Dentistry, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Republic of Korea
| | - Jung-Hwa Lim
- Department of Prosthodontics, Yonsei University College of Dentistry, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Republic of Korea
| | - Chan-Gyu Lee
- Department of Prosthodontics, Yonsei University College of Dentistry, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Republic of Korea; Oral Science Research Center, Yonsei University College of Dentistry, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Republic of Korea
| | - Keun-Woo Lee
- Dental Hospital, Veterans Health Service Medical Center, Seoul, 05368, Republic of Korea; Department of Prosthodontics, Yonsei University College of Dentistry, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Republic of Korea
| | - Sung-Yong Kim
- Dental Hospital, Veterans Health Service Medical Center, Seoul, 05368, Republic of Korea.
| | - Jong-Eun Kim
- Department of Prosthodontics, Yonsei University College of Dentistry, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Republic of Korea.
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Lankes V, Reymus M, Mayinger F, Coldea A, Liebermann A, Hoffmann M, Stawarczyk B. Three-Dimensional Printed Resin: Impact of Different Cleaning Protocols on Degree of Conversion and Tensile Bond Strength to a Composite Resin Using Various Adhesive Systems. MATERIALS (BASEL, SWITZERLAND) 2023; 16:ma16093580. [PMID: 37176461 PMCID: PMC10179867 DOI: 10.3390/ma16093580] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Revised: 05/03/2023] [Accepted: 05/05/2023] [Indexed: 05/15/2023]
Abstract
The present investigation tested the effect of cleaning methods and adhesives on the tensile bond strength (TBS) of a resin-based composite luted to a temporary 3D printed resin. Substrates (n= 360) were printed using a Rapidshape D20II and cleaned with a butyldiglycol-based solution, isopropanol, or by centrifugation. Specimens were air-abraded with Al2O3 (mean particle size 50 µm) at 0.1 MPa followed by pretreatment (n = 30/subgroup) with: (1) Clearfil Ceramic Primer (CCP); (2) Clearfil Universal Bond (CUB); (3) Scotchbond Universal Plus (SUP) or 4. Visio.link (VL) and luted to PanaviaV5. TBS (n = 15/subgroup) was measured initially (24 h at 37 °C water) or after thermal cycling (10,000×, 5/55 °C). The degree of conversion (DC) for each cleaning method was determined prior and after air-abrasion. Univariate ANOVA followed by post-hoc Scheffé test was computed (p < 0.05). Using Ciba-Geigy tables and chi-square, failure types were analyzed. The DC values were >85% after all cleaning methods, with centrifugation showing the lowest. CCP pretreatment exhibited the lowest TBS values, with predominantly adhesive failures. The combination of CCP and centrifugation increased the TBS values (p < 0.001) compared to the chemical cleaning. CUB, SUP, and VL, regardless of cleaning, can increase the bond strength between the 3D printed resin and the conventional luting resin.
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Affiliation(s)
- Valerie Lankes
- Department of Prosthetic Dentistry, University Hospital, LMU Munich, 80336 Munich, Germany
| | - Marcel Reymus
- Department of Conservative Dentistry and Peridontology, University Hospital, LMU Munich, 80336 Munich, Germany
| | - Felicitas Mayinger
- Department of Prosthetic Dentistry, University Hospital, LMU Munich, 80336 Munich, Germany
| | - Andrea Coldea
- Department of Prosthetic Dentistry, University Hospital, LMU Munich, 80336 Munich, Germany
| | - Anja Liebermann
- Head of the Department of Prosthetic Dentistry, Faculty of Medicine and University Hospital Cologne, 50931 Cologne, Germany
| | - Moritz Hoffmann
- Department of Prosthetic Dentistry, University Hospital, LMU Munich, 80336 Munich, Germany
| | - Bogna Stawarczyk
- Scientific Head Dental Material Unit, Department of Prosthetic Dentistry, University Hospital, LMU Munich, 80336 Munich, Germany
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Folwaczny M, Ahantab R, Kessler A, Ern C, Frasheri I. Cytotoxicity of 3D printed resin materials for temporary restorations on human periodontal ligament (PDL-hTERT) cells. Dent Mater 2023; 39:529-537. [PMID: 37055304 DOI: 10.1016/j.dental.2023.04.003] [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] [Received: 10/24/2022] [Revised: 04/03/2023] [Accepted: 04/05/2023] [Indexed: 04/15/2023]
Abstract
OBJECTIVES Various dental resin materials are available for the fabrication of temporary restorations using modern additive printing methods. Albeit these materials are placed for several months in intimate contact with dental hard and soft tissues, including the gingival crevice, there exists only insufficient evidence on the biocompatibility of these materials. This in vitro study aimed to delineate the biocompatibility of 3D printable materials on periodontal ligament cells (PDL-hTERTs). METHODS Samples of four dental resin materials for additive fabrication of temporary restorations using 3D printing (MFH, Nextdent; GC Temp, GC; Freeprint temp, Detax; 3Delta temp, Deltamed), one material for subtractive fabrication (Grandio disc, Voco) and one conventional temporary material (Luxatemp, DMG) were prepared with a standardized size according to the manufacturer's instructions. Human PDL-hTERTs were exposed to resin specimens or eluates of the material for 1, 2, 3, 6 and 9 days. For determination of cell viability, XTT assays were performed. In addition, the expression of the proinflammatory cytokines interleukin 6 and 8 (IL-6 and 8) was assessed in the supernatants with ELISA. Cell viability and the expression of IL-6 and 8 in presence of the resin material or their eluates was compared with untreated controls. Immunofluorescence staining for IL-6 and IL-8, as well as scanning electron microscopy of the discs after culturing, were performed. Differences between groups were analyzed with Student´s t-test for unpaired samples. RESULTS Compared to untreated control samples, the exposure against the resin specimen induced strong reduction of cell viability in case of the conventional material Luxatemp (p < 0.001) and the additive material 3Delta temp (p < 0.001) irrespective of the observation period. On the contrary, the presence of eluates of the various materials induced only minor changes in cell viability. Considering IL-6 (day 2: p = 0.001; day 6 and 9: p < 0.001) and IL-8 (day 1: p = 0.001; day 2, 3, 6, 9: p < 0.001) their expression was strongly reduced in presence of the eluate of Luxatemp. Except for IL-6 at day 1 and 6 also the material 3Delta temp caused significant reduction of both proinflammatory mediators at any time point. SIGNIFICANCE The conventional material Luxatemp and the additive material 3Delta temp appear to severely affect cell viability when in direct contact with PDL-hTERTs. The other tested materials of this new category of additive materials and the subtractive material Grandio seem to induce only minor changes in direct contact with these cells. Therefore, they could serve as a viable alternative in the fabrication of temporary restorations.
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Affiliation(s)
- Matthias Folwaczny
- Department of Conservative Dentistry and Periodontology, University Hospital, Ludwig-Maximilians-University, Goethestr. 70, D-80336 Munich, Germany.
| | - Roya Ahantab
- Department of Conservative Dentistry and Periodontology, University Hospital, Ludwig-Maximilians-University, Goethestr. 70, D-80336 Munich, Germany
| | - Andreas Kessler
- Department of Conservative Dentistry and Periodontology, University Hospital, Ludwig-Maximilians-University, Goethestr. 70, D-80336 Munich, Germany
| | - Christina Ern
- Department of Conservative Dentistry and Periodontology, University Hospital, Ludwig-Maximilians-University, Goethestr. 70, D-80336 Munich, Germany
| | - Iris Frasheri
- Department of Conservative Dentistry and Periodontology, University Hospital, Ludwig-Maximilians-University, Goethestr. 70, D-80336 Munich, Germany
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Rosentritt M, Rauch A, Hahnel S, Schmidt M. In-vitro performance of subtractively and additively manufactured resin-based molar crowns. J Mech Behav Biomed Mater 2023; 141:105806. [PMID: 37001248 DOI: 10.1016/j.jmbbm.2023.105806] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 03/21/2023] [Accepted: 03/24/2023] [Indexed: 03/29/2023]
Abstract
PURPOSE To compare the in-vitro performance and wear behavior of additively or subtractively fabricated resin-based composite molar crowns for temporary and permanent application. MATERIALS AND METHODS Identical molar crowns (n = 8 per group) were manufactured from materials for temporary or permanent application (3x temporary additive fabrication, 3x additive permanent fabrication, 1x temporary subtractive fabrication, 1x permanent subtractive fabrication). All crowns were adhesively bonded (Calibra Universal, Dentsply Sirona, USA) on standardized resin-based composite molars (FDI 46, P Pro temporary Crown & Bridge). Thermal cycling and mechanical loading (2 × 3000 × 5°C/55 °C, 2min, H20 dist., 1.2 × 106 force 50N) were performed and fracture force was determined (v = 1 mm/min, Z010, Zwick, Germany). Mean wear, maximum wear, and roughness were investigated on polished (P1200) specimens (n = 8 per group, d = 8 mm) in a pin-on-block test (50N; 120000 cycles; 1.6Hz; H2O). Statistics were performed by using one-way ANOVA, Bonferroni post-hoc-tests, and Pearson-correlation (α = 0.05). RESULTS All crowns survived TCML without failures. Fracture forces ranged from 1362.4 ± 182.4N to 2354.1 ± 373.3N for the additive temporary crowns, from 1680.4.4 ± 525.1N to 2601.6 ± 403.7N for the additive permanent crowns, and reached values of 2988.5 ± 604.7N for subtractive temporary crowns and 3092.0 ± 307.6 N for subtractive permanent crowns. Significant (p < 0.001) differences were identified between the various additively manufactured systems, but not for the subtractively fabricated systems (p = 0.673). Mean wear of the additive temporary crowns ranged between 114.5 ± 25.8 μm and 163.8 ± 21.4 μm without significant differences (p = 0.061). Mean wear of the additive permanent crowns ranged between 120.0 ± 27.5 μm and 171.3 ± 31.8 μm with significant differences (p = 0.004). No statistically significant differences were identified between temporary and permanent subtractively manufactured specimens, with mean wear ranging between 140.5 ± 51.1 μm and 176.6 ± 26.8 μm (p = 0.673). Maximum wear of additive temporary specimens ranged between 221.4.5 ± 53.3 μm and 322.1 ± 50.6 μm; significant differences were identified between the groups (p = 0.016). Maximum wear of additive permanent specimens ranged between 246.3 ± 47.3 μm and 337.4 ± 61.4 μm, and significant differences were identified between the groups (p = 0.006). Mean wear of the subtractive group (permanent and temporary) showed no differences in maximum wear from 277.9 ± 79.7.1 μm to 316.4 ± 58.1 μm (p = 0.288). Ra roughness ranged from 0.7 ± 0.2 μm to 3.6 ± 1.3 μm with significant differences (p < 0.001) and Rz reference between 65.9 ± 26.2 μm and 16.8 ± 6.3 μm. CONCLUSION Temporary and permanent molar crowns provided at least acceptable in-vitro performance and fracture force for clinical mid-term application. Laboratory wear stability of the resin-based materials appeared sufficient, but should be verified under clinical conditions.
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Jeršovaitė J, Šarachovaitė U, Matulaitienė I, Niaura G, Baltriukienė D, Malinauskas M. Biocompatibility enhancement via post-processing of microporous scaffolds made by optical 3D printer. Front Bioeng Biotechnol 2023; 11:1167753. [PMID: 37122855 PMCID: PMC10130666 DOI: 10.3389/fbioe.2023.1167753] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Accepted: 03/30/2023] [Indexed: 05/02/2023] Open
Abstract
Providing a 3D environment that mimics the native extracellular matrix is becoming increasingly important for various applications such as cell function studies, regenerative medicine, and drug discovery. Among the most critical parameters to consider are the scaffold's complicated micro-scale geometry and material properties. Therefore, stereolithography based on photopolymerization is an emerging technique because of its ability to selectively form volumetric structures from liquid resin through localized polymerization reactions. However, one of the most important parameters of the scaffold is biocompatibility, which depends not only on the material but also on the exposure conditions and post-processing, which is currently underestimated. To investigate this systematically, microporous scaffolds with pore sizes of 0.05 mm3 corresponding to a porosity of 16,4% were fabricated using the stereolithography printer Asiga PICO2 39 UV from the widely used resins FormLabs Clear and Flexible. The use of various polymers is usually limited for cells because, after wet chemical development, the non-negligible amount of remaining monomers intertwined in the photopolymerized structures is significantly toxic to cells. Therefore, the aim of this research was to find the best method to remove monomers from the 3D scaffold by additional UV exposure. For this purpose, a Soxhlet extractor was used for the first time, and the monomers were immersed in different alcohols. A Raman microspectroscopy was also used to investigate whether different post-processing methods affect DC (cross-linking) to find out if this specifically affects the biocompatibility of the scaffolds. Finally, mesenchymal stem cells from rat dental pulp were examined to confirm the increased biocompatibility of the scaffolds and their ability to support cell differentiation into bone tissue cells.
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Affiliation(s)
- Jurga Jeršovaitė
- Laser Research Center, Faculty of Physics, Vilnius University, Vilnius, Lithuania
| | - Ugnė Šarachovaitė
- Institute of Biochemistry, Life Sciences Center, Vilnius University, Vilnius, Lithuania
| | - Ieva Matulaitienė
- Department of Organic Chemistry, Center for Physical Sciences and Technology, Vilnius, Lithuania
| | - Gediminas Niaura
- Department of Organic Chemistry, Center for Physical Sciences and Technology, Vilnius, Lithuania
| | - Daiva Baltriukienė
- Institute of Biochemistry, Life Sciences Center, Vilnius University, Vilnius, Lithuania
| | - Mangirdas Malinauskas
- Laser Research Center, Faculty of Physics, Vilnius University, Vilnius, Lithuania
- *Correspondence: Mangirdas Malinauskas,
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Kang MJ, Lim JH, Lee CG, Kim JE. Effects of Post-Curing Light Intensity on the Mechanical Properties and Three-Dimensional Printing Accuracy of Interim Dental Material. MATERIALS (BASEL, SWITZERLAND) 2022; 15:6889. [PMID: 36234230 PMCID: PMC9570601 DOI: 10.3390/ma15196889] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 09/28/2022] [Accepted: 09/30/2022] [Indexed: 06/16/2023]
Abstract
This study evaluated the effects of the light intensity of curing and the post-curing duration on the mechanical properties and accuracy of the interim dental material. After designing the specimen, 3D printing was performed, and the light intensity was divided into groups G20, G60, G80, and G120 (corresponding to 1.4−1.6, 2.2−3.0, 3.8−4.4, and 6.4−7.0 mW/cm2, respectively), with no post-curing or 5, 10, or 20 min of post-curing being performed. The flexural properties, Vickers microhardness, degree of conversion (DC), and 3D accuracy were then evaluated. The flexural properties and Vickers microhardness showed a sharp increase at the beginning of the post-curing and then tended to increase gradually as the light intensity and post-curing time increased (p < 0.001). On the other hand, there was no significant difference between groups in the accuracy analysis of a 3D-printed three-unit bridge. These results indicate that the light intensity of the post-curing equipment influences the final mechanical properties of 3D-printed resin and that post-curing can be made more efficient by optimizing the light intensity and post-curing time.
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