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Šimunović L, Jurela A, Sudarević K, Bačić I, Haramina T, Meštrović S. Influence of Post-Processing on the Degree of Conversion and Mechanical Properties of 3D-Printed Polyurethane Aligners. Polymers (Basel) 2023; 16:17. [PMID: 38201683 PMCID: PMC10780983 DOI: 10.3390/polym16010017] [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: 11/30/2023] [Revised: 12/12/2023] [Accepted: 12/18/2023] [Indexed: 01/12/2024] Open
Abstract
BACKGROUND This study explores how different post-processing methods affect the mechanical properties and degree of conversion of 3d-printed polyurethane aligners made from Tera Harz TC-85 resin. METHODS Using Fourier-transform infrared (FTIR) spectroscopy, the degree of conversion of liquid resin and post-processed materials was analyzed. This investigation focused on the effects of various post-curing environments (nitrogen vs. air) and rinsing protocols (centrifuge, ethanol, isopropanol, and isopropanol + water). The assessed mechanical properties were flexural modulus and hardness. RESULTS The degree of conversion showed no significant variance across different groups, though the polymerization environment influenced the results, accounting for 24.0% of the variance. The flexural modulus varied considerably, depending on both the rinsing protocol and the polymerization environment. The standard protocol (centrifugation followed by nitrogen polymerization) exhibited the highest flexural modulus of 1881.22 MPa. Hardness testing revealed significant differences, with isopropanol treatments showing increased resistance to wear in comparison to the centrifuge and ethanol rinse treatments. CONCLUSIONS This study conclusively demonstrates the adverse effects of oxygen on the polymerization process, underscoring the critical need for an oxygen-free environment to optimize material properties. Notably, the ethanol rinse followed by nitrogen polymerization protocol emerged as a viable alternative to the conventional centrifuge plus nitrogen method.
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Affiliation(s)
- Luka Šimunović
- Department of Orthodontics, School of Dental Medicine, University of Zagreb, 10000 Zagreb, Croatia;
| | - Antonija Jurela
- Dental Clinic Fiziodent, 10000 Zagreb, Croatia; (A.J.); (K.S.)
| | - Karlo Sudarević
- Dental Clinic Fiziodent, 10000 Zagreb, Croatia; (A.J.); (K.S.)
| | - Ivana Bačić
- Forensic Science Centre “Ivan Vučetić”, Ministry of the Interior, 10000 Zagreb, Croatia;
| | - Tatjana Haramina
- Department of Materials, Faculty of Electrical Engineering and Computing, University of Zagreb, 10000 Zagreb, Croatia;
| | - Senka Meštrović
- Department of Orthodontics, School of Dental Medicine, University of Zagreb, 10000 Zagreb, Croatia;
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Alsunbul H, Khan AA, Alqahtani YM, Hassan SAB, Asiri W, Saadaldin S, Alharthi R, Aldegheishem A. Using Functionalized Micron-Sized Glass Fibres for the Synergistic Effect of Glass Ionomer on Luting Material. J Funct Biomater 2023; 14:550. [PMID: 37998119 PMCID: PMC10672604 DOI: 10.3390/jfb14110550] [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: 10/22/2023] [Revised: 11/09/2023] [Accepted: 11/14/2023] [Indexed: 11/25/2023] Open
Abstract
This laboratory experiment was conducted with the objective of augmenting the mechanical properties of glass ionomer cement (GIC) via altering the composition of GIC luting powder through the introduction of micron-sized silanized glass fibres (GFs). Experimental GICs were prepared through the addition of two concentrations of GFs (0.5% and 1.0% by weight) to the powder of commercially available GIC luting materials. The effect of GF in set GIC was internally evaluated using micro-CT while the mechanical attributes such as nano hardness (nH), elastic modulus (EM), compressive strength (CS), and diametral tensile strength (DTS) were gauged. Additionally, the physical properties such as water solubility and sorption, contact angle (CA), and film thickness were evaluated. Reinforced Ketac Cem Radiopaque (KCR) GIC with 0.5 wt.% GF achieved improved nH, EM, CS, and DTS without affecting the film thickness, CA or internal porosity of the set GIC cement. In contrast, both GF-GIC formulations of Medicem (MC) GIC showed the detrimental effect of the GF incorporation. Reinforcing KCR GIC with 0.5 wt.% silanized GFs could improve the physical and mechanical attributes of luting material. Silanized GF, with optimal concentration within the GIC powder, can be used as a functional additive in KCR GIC with promising results.
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Affiliation(s)
- Hanan Alsunbul
- Restorative Dentistry Department, College of Dentistry, King Saud University, Riyadh 11451, Saudi Arabia;
| | - Aftab Ahmed Khan
- Dental Health Department, College of Applied Medical Sciences, King Saud University, Riyadh 11451, Saudi Arabia
| | - Yasser M. Alqahtani
- Restorative Dentistry Department, Ministry of Health, Abha 61321, Saudi Arabia;
| | - Saeed Awod bin Hassan
- Restorative Dental Sciences Department, College of Dentistry, King Khalid University, Abha 61321, Saudi Arabia;
| | - Waleed Asiri
- Restorative Dentistry Department, College of Dentistry, Najran University, Najran 66454, Saudi Arabia;
| | - Selma Saadaldin
- Prosthodontics Division, Schulich School of Medicine and Dentistry, Western University, London, ON N6A 5B9, Canada;
| | - Rasha Alharthi
- Clinical Dental Science Department, College of Dentistry, Princess Nourah bint Abdulrahman University, Riyadh 11671, Saudi Arabia; (R.A.); (A.A.)
| | - Alhanoof Aldegheishem
- Clinical Dental Science Department, College of Dentistry, Princess Nourah bint Abdulrahman University, Riyadh 11671, Saudi Arabia; (R.A.); (A.A.)
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Roberts H, Berzins D, Nicholson J. Long-Term Water Balance Evaluation in Glass Ionomer Restorative Materials. MATERIALS 2022; 15:ma15030807. [PMID: 35160751 PMCID: PMC8836498 DOI: 10.3390/ma15030807] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 01/13/2022] [Accepted: 01/14/2022] [Indexed: 02/01/2023]
Abstract
The complex role of water in glass ionomer cement (polyalkenoate) dental restorative materials has been studied, but much of the present understanding concerning water balance within these materials is based on very early studies and short-term experiments. This study evaluated the nature of the water species of six conventional and four resin modified glass ionomer restorative materials over 3 years using thermogravimetric analysis techniques. Materials were prepared, placed in crucibles, and stored in physiologic phosphate buffered saline and evaluated at 24 h, 1 week, and then at 1, 3, 6, 9, 12, 18, 24, 30 and 36 months. All materials demonstrated a significant increase in unbound water percentage content but except for the resin modified materials, the enthalpy required to remove the unbound water species did not significantly change over 36 months. Also, bound water content percentage and removal enthalpy was established at 24 h, as no significant increase was noted in both bound water content and removal enthalpy over the course of this evaluation. This study suggests that unbound water species may increase with time and is loosely held except for the resin modified materials. Protective coatings placement and re-evaluation are prudent to prevent unbound water loss.
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Affiliation(s)
- Howard Roberts
- Dental Biomaterials Research, College of Dentistry, University of Kentucky, Lexington, KY 40536, USA
- Correspondence: ; Tel.: +1-(847)-910-4255
| | - David Berzins
- Graduate Dental Biomaterials, School of Dentistry, Marquette University, Milwaukee, WI 53233, USA;
| | - John Nicholson
- Bluefield Centre for Biomaterials, UK and Dental Physical Sciences, Barts & The London School of Medicine and Dentistry, Queen Mary University of London, London E1 4NS, UK;
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Agha A, Parker S, Parkinson EK, Patel M. Characteristics of experimental resin-modified glass-ionomer cements, containing alternate monomers to HEMA. Dent Mater 2021; 37:1542-1552. [PMID: 34462139 DOI: 10.1016/j.dental.2021.08.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 07/31/2021] [Accepted: 08/04/2021] [Indexed: 11/24/2022]
Abstract
OBJECTIVE Resin-modified glass ionomer cements (RMGICs) present several advantages (e.g. fluoride release), but their reported cytotoxicity has been associated with hydroxyethyl methacrylate (HEMA) monomer release. Therefore, different monomers were tested for use in RMGICs in order to improve their biocompatibility and reduce monomer release. METHODS Eight experimental liquid compositions were prepared replacing different percentages of HEMA (conventional monomer used in commercial RMGICs) with hydroxypropyl-methacrylate (HPM) and/or tetrahydrofurfuryl-methacrylate (THFM), which are known to have better biocompatibility. Moreover, two commercial materials (Fuji-Plus and RelyX) and two compositions, based on these (home), were included as controls. Monomer release of all materials (commercial, home and experimental) were tested using high-performance liquid chromatography (HPLC) methods after immersing discs in deionized-water (DW) or ethanol:DW. Cytotoxicity of the materials extracts was tested on normal human oral fibroblast line (NHOF-1) using 3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide (MTT) assay. RESULTS Three experimental materials containing THFM (F3, R3 and R4) showed less or similar monomer release compared to corresponding commercial products. Furthermore, two experimental materials (F3 and F4) showed similar effects on NHOF-1 cells compared to the negative control medium. SIGNIFICANCE The lower monomer release and higher cell viability of some experimental THFM compositions are encouraging. THFM partially replacing HEMA is potentially a suitable alternative for producing biocompatible RMGICs.
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Affiliation(s)
- Amani Agha
- Centre for Oral Bioengineering, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, E1 4NS, United Kingdom.
| | - Sandra Parker
- Centre for Oral Bioengineering, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, E1 4NS, United Kingdom
| | - Eric Kenneth Parkinson
- Clinical and Diagnostic Oral Sciences, Queen Mary University of London, E1 2AT, United Kingdom
| | - Mangala Patel
- Centre for Oral Bioengineering, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, E1 4NS, United Kingdom
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Delgado AHS, Owji N, Ashley P, Young AM. Varying 10-methacryloyloxydecyl dihydrogen phosphate (10-MDP) level improves polymerisation kinetics and flexural strength in self-adhesive, remineralising composites. Dent Mater 2021; 37:1366-1376. [PMID: 34144796 DOI: 10.1016/j.dental.2021.06.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 05/28/2021] [Accepted: 06/02/2021] [Indexed: 10/21/2022]
Abstract
OBJECTIVES To assess the influence of systematically varying concentrations of 10-methacryloyloxydecyl dihydrogen phosphate (10-MDP) versus 3% 4-META on the polymerisation kinetics and shrinkage, biaxial flexural strength (BFS) and modulus of remineralising composites. METHODS Composites were prepared by adding poly(propylene glycol) dimethacrylate (24 wt%), camphorquinone (1 wt%) and MDP (0%, 5%, 10%, 15% and 20 wt%) or 4-META (3%) to urethane dimethacrylate. These were mixed with glass fillers containing 8 wt% monocalcium phosphate and 4 wt% polylysine (powder-liquid ratio of 3:1). Continuous spectral changes, following 20 s light exposure (37 °C), were assessed with an ATR-FTIR to monitor polymerisation kinetics (n = 3). Final extrapolated conversions (DC,max) were employed to calculate polymerisation shrinkage. BFS and modulus of 24-h dry stored disc specimens (10 × 1 mm; n = 10) were determined using a ball-on-ring jig setup. RESULTS Maximum rate of polymerisation and DC,max increased linearly from 2.5 to 3.5% s-1 and 67 to 83%, respectively, upon increasing MDP from 0 to 20 wt%. Values with 3% 4-META were 2.6% s-1 and 78%. Shrinkage was 3.8 ± 0.3% for all formulations. Raising 4-META or MDP from 0 to 3 versus 5%, respectively, increased strength from 106 to 145 versus 136 MPa. A decreasing trend with higher MDP concentrations was noted. Elastic modulus showed no specific trend upon MDP increase. SIGNIFICANCE Whilst final conversion levels were enhanced by 3% 4-META or >5% MDP, trends did not correlate with strength. Peak strengths with 3% 4-META or 5% MDP may therefore be due to acidic monomers providing linkage between the hydrophilic, non-silane treated particles and the polymer matrix.
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Affiliation(s)
- António H S Delgado
- Division of Biomaterials and Tissue Engineering, UCL Eastman Dental Institute, London, UK; Centro de Investigação Interdisciplinar Egas Moniz (CiiEM), Monte de Caparica, Almada, Portugal.
| | - Nazanin Owji
- Division of Biomaterials and Tissue Engineering, UCL Eastman Dental Institute, London, UK
| | - Paul Ashley
- Division of Biomaterials and Tissue Engineering, UCL Eastman Dental Institute, London, UK; Unit of Paediatric Dentistry, Department of Craniofacial Growth and Development, UCL Eastman Dental Institute, London, UK
| | - Anne M Young
- Division of Biomaterials and Tissue Engineering, UCL Eastman Dental Institute, London, UK
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Delgado AHS, Young AM. Methacrylate peak determination and selection recommendations using ATR-FTIR to investigate polymerisation of dental methacrylate mixtures. PLoS One 2021; 16:e0252999. [PMID: 34106972 PMCID: PMC8189511 DOI: 10.1371/journal.pone.0252999] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Accepted: 05/26/2021] [Indexed: 01/03/2023] Open
Abstract
Investigation of polymerisation kinetics using ATR-FTIR systems is common in many dental studies. However, peak selection methods to calculate monomer-polymer conversion can vary, consequently affecting final results. Thus, the aim of this study is to experimentally confirm which method is less prone to systematic errors. Three commercial restorative materials were tested-Vertise Flow (VF), Constic and Activa Bioactive Restorative Kids. Firstly, Attenuated Total Reflectance Fourier Transform Infra-Red (ATR-FTIR) (Spectrum One, Perkin-Elmer, UK) spectra of monomers were acquired-10-methacryloyloxy decyl dihydrogen phosphate (10-MDP), bisphenol-A glycidyl dimethacrylate (Bis-GMA), 2-hydroxyethyl methacrylate (HEMA), triethyelene glycol dimethacrylate (TEGDMA) and urethane dimethacrylate (UDMA) to investigate proportionality of methacrylate peak heights versus concentration. Spectral changes upon light exposure of 2 mm discs of the restorative materials (irradiated for 20 s, LED curing unit 1100-1330 mW/cm2) were assessed to study polymerisation kinetics (n = 3), with continuous acquisition of spectra, before, during and after light exposure. Peak differences and degrees of conversion (DC %) were calculated using 1320/1336, 1320/1350 and 1636/1648 cm-1 as reaction/reference peaks. Inferential statistics included a MANOVA and within-subjects repeated measures ANOVA design (5% significance level). Proportionality of methacrylate peak height to concentration was confirmed, with the 1320/1352 cm-1 peak combination showing the lowest coefficient of variation (8%). Difference spectra of the polymerisation reaction showed noise interference around the 1500-1800 cm-1 region. Across the different materials, DC % results are highly dependent upon peak selection (p<0.001), with higher variability associated to the 1636 cm-1. Significant differences in the materials were only detected when the 1320 cm-1 peak was used (p<0.05). Within the same materials, methods were significantly different for Constic and Activa (p<0.05). It is possible to conclude that the 1320 cm-1 peak is more adequate to assess polymerisation of methacrylates and is therefore recommended.
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Affiliation(s)
- António H. S. Delgado
- Division of Biomaterials and Tissue Engineering, UCL Eastman Dental Institute, London, United Kingdom
- Centro de Investigação Interdisciplinar Egas Moniz (CiiEM), Instituto Universitário Egas Moniz, Monte de Caparica, Portugal
| | - Anne M. Young
- Division of Biomaterials and Tissue Engineering, UCL Eastman Dental Institute, London, United Kingdom
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Kaczmarek K, Leniart A, Lapinska B, Skrzypek S, Lukomska-Szymanska M. Selected Spectroscopic Techniques for Surface Analysis of Dental Materials: A Narrative Review. MATERIALS (BASEL, SWITZERLAND) 2021; 14:2624. [PMID: 34067921 PMCID: PMC8156406 DOI: 10.3390/ma14102624] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/17/2021] [Revised: 05/09/2021] [Accepted: 05/11/2021] [Indexed: 12/18/2022]
Abstract
The presented work focuses on the application of spectroscopic methods, such as Infrared Spectroscopy (IR), Fourier Transform Infrared Spectroscopy (FT-IR), Raman spectroscopy, Ultraviolet and Visible Spectroscopy (UV-Vis), X-ray spectroscopy, and Mass Spectrometry (MS), which are widely employed in the investigation of the surface properties of dental materials. Examples of the research of materials used as tooth fillings, surface preparation in dental prosthetics, cavity preparation methods and fractographic studies of dental implants are also presented. The cited studies show that the above techniques can be valuable tools as they are expanding the research capabilities of materials used in dentistry.
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Affiliation(s)
- Katarzyna Kaczmarek
- Department of Inorganic and Analytical Chemistry, Faculty of Chemistry, University of Lodz, 12 Tamka St., 91-403 Lodz, Poland; (A.L.); (S.S.)
| | - Andrzej Leniart
- Department of Inorganic and Analytical Chemistry, Faculty of Chemistry, University of Lodz, 12 Tamka St., 91-403 Lodz, Poland; (A.L.); (S.S.)
| | - Barbara Lapinska
- Department of General Dentistry, Medical University of Lodz, 251 Pomorska St., 92-213 Lodz, Poland;
| | - Slawomira Skrzypek
- Department of Inorganic and Analytical Chemistry, Faculty of Chemistry, University of Lodz, 12 Tamka St., 91-403 Lodz, Poland; (A.L.); (S.S.)
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