1
|
Mudhaffer S, Althagafi R, Haider J, Satterthwaite J, Silikas N. Effects of printing orientation and artificial ageing on martens hardness and indentation modulus of 3D printed restorative resin materials. Dent Mater 2024:S0109-5641(24)00104-0. [PMID: 38735775 DOI: 10.1016/j.dental.2024.05.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2024] [Revised: 04/29/2024] [Accepted: 05/03/2024] [Indexed: 05/14/2024]
Abstract
BACKGROUND Three-dimensional (3D) printing is increasingly used to fabricate dental restorations due to its enhanced precision, consistency and time and cost-saving advantages. The properties of 3D-printed resin materials can be influenced by the chosen printing orientation which can impact the mechanical characteristics of the final products. PURPOSE The objective of this study was to evaluate the influence of printing orientation and artificial ageing on the Martens hardness (HM) and indentation modulus (EIT) of 3D-printed definitive and temporary dental restorative resins. METHODS Disk specimens (20 mm diameter × 2 mm height) were additively manufactured in three printing orientations (0°, 45°, 90°) using five 3D-printable resins: VarseoSmile Crownplus (VCP), Crowntec (CT), Nextdent C&B MFH (ND), Dima C&B temp (DT), and GC temp print (GC). The specimens were printed using a DLP 3D-printer (ASIGA MAX UV), while LavaTM Ultimate (LU) and Telio CAD (TC) served as milled control materials. Martens hardness (HM) and indentation modulus (EIT) were tested both before and after storage in distilled water and artificial saliva for 1, 30, and 90 days at 37 °C. RESULTS 90° printed specimens exhibited higher HM than the other orientations at certain time points, but no significant differences were observed in HM and EIT between orientations for all 3D-printed materials after 90 days of ageing in both aging media. LU milled control material exhibited the highest HM and EIT among the tested materials, while TC, the other milled control, showed similar values to the 3D printed resins. CT and VCP (definitive resins) and ND displayed higher Martens parameters compared to DT and GC (temporary resins). The hardness of the 3D-printed materials was significantly impacted by artificial ageing compared to the controls, with ND having the least hardness reduction percentage amongst all 3D-printed materials. The hardness reduction percentage in distilled water and artificial saliva was similar for all materials except for TC, where higher reduction was noted in artificial saliva. SIGNIFICANCE The used 3D printed resins cannot yet be considered viable alternatives to milled materials intended for definitive restorations but are preferable for use as temporary restorations.
Collapse
Affiliation(s)
- Shaymaa Mudhaffer
- Division of Dentistry, School of Medical Sciences, University of Manchester, Manchester, UK; Substitutive Dental Sciences, Faculty of Dentistry, Taibah University, Madinah, Saudi Arabia.
| | - Rana Althagafi
- Substitutive Dental Sciences, Faculty of Dentistry, Taibah University, Madinah, Saudi Arabia
| | - Julfikar Haider
- Division of Dentistry, School of Medical Sciences, University of Manchester, Manchester, UK; Department of Engineering, Manchester Metropolitan University, Manchester, UK
| | - Julian Satterthwaite
- Division of Dentistry, School of Medical Sciences, University of Manchester, Manchester, UK
| | - Nick Silikas
- Division of Dentistry, School of Medical Sciences, University of Manchester, Manchester, UK.
| |
Collapse
|
2
|
Schmeiser F, Arbogast F, Ruppel H, Mayinger F, Reymus M, Stawarczyk B. Methodology investigation: Impact of crown geometry, crown, abutment and antagonist material and thermal loading on the two-body wear of dental materials. Dent Mater 2021; 38:266-280. [PMID: 34953628 DOI: 10.1016/j.dental.2021.12.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Revised: 11/19/2021] [Accepted: 12/08/2021] [Indexed: 11/03/2022]
Abstract
OBJECTIVES To investigate the impact of crown geometry, crown/abutment/antagonist material and thermal loading on the two-body wear of dental materials caused by chewing simulation. MATERIALS AND METHODS For the crown geometry, crowns (polymethylmethacrylate (PMMA), polyetheretherketone (PEEK) and silicate ceramic (SiO2)) were milled with a flat, steep, or medium cusp inclination (CINC). For the crown/abutment material, crowns (PMMA, PEEK and SiO2) were combined with PMMA, polymer-infiltrated-ceramic-network (PICN), cobalt-chrome alloy (CoCr) and natural teeth (ENAM) abutments. For the antagonist material, antagonists were fabricated from PICN, CAD/CAM resin composite (RECO), steatite (STEA), steel (STL) and ENAM and tested against flat specimens (substrates) made of veneering ceramic (VC). For thermal loading, the duration (30 s, 60 s, 120 s) and presence of temperature changes (37 °C versus 5 °C/55 °C) was varied. Material losses were determined by matching scanned specimens before and after aging (400,000 chewing cycles, 50 N, 1.3 Hz). Martens parameters were determined for the antagonists/substrates. Data were analyzed using Kolmogorov-Smirnov-test, Kruskal-Wallis H, Scheffé-Post-Hoc-tests, pairwise comparisons, Bonferroni correction, one-way ANOVA, Mann-Whitney-U and Spearman rho. RESULTS PMMA crowns presented the highest and PEEK the lowest material losses. Flat CINC showed the lowest material losses for PEEK and SiO2 crowns. CoCr and ENAM abutments presented material losses in the same range. Antagonist and cumulative material losses for RECO and ENAM were similar. Thermal loading did not influence material losses. SIGNIFICANCE Crown geometry influences the crown and antagonists wear, with an increased cusp inclination entailing increased wear. For in vitro set-ups, CoCr abutments and RECO antagonists present valid alternatives to natural teeth. For polymers, in vitro chewing simulations may be performed at a constant temperature (37 °C).
Collapse
Affiliation(s)
- Felix Schmeiser
- Dental Material Unit, Department of Prosthetic Dentistry, University Hospital Ludwig-Maximilians-University, Goethestrasse 70, 80336 Munich, Germany.
| | - Fee Arbogast
- Dental Material Unit, Department of Prosthetic Dentistry, University Hospital Ludwig-Maximilians-University, Goethestrasse 70, 80336 Munich, Germany
| | - Hendrik Ruppel
- Dental Material Unit, Department of Prosthetic Dentistry, University Hospital Ludwig-Maximilians-University, Goethestrasse 70, 80336 Munich, Germany
| | - Felicitas Mayinger
- Dental Material Unit, Department of Prosthetic Dentistry, University Hospital Ludwig-Maximilians-University, Goethestrasse 70, 80336 Munich, Germany
| | - Marcel Reymus
- Department of Conservative Dentistry and Periodontology, University Hospital Ludwig-Maximilians-University, Goethestrasse 70, 80336 Munich, Germany
| | - Bogna Stawarczyk
- Dental Material Unit, Department of Prosthetic Dentistry, University Hospital Ludwig-Maximilians-University, Goethestrasse 70, 80336 Munich, Germany
| |
Collapse
|
3
|
Ilie N, Schmalz G, Fujioka-Kobayashi M, Lussi A, Price RB. Correlation of the mechanical and biological response in light-cured RBCs to receiving a range of radiant exposures: Effect of violet light. J Dent 2021; 105:103568. [PMID: 33385531 DOI: 10.1016/j.jdent.2020.103568] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Revised: 12/11/2020] [Accepted: 12/23/2020] [Indexed: 11/21/2022] Open
Abstract
OBJECTIVE This study correlates the mechanical and biological response of commercially available resin-based composites (RBCs) to clinically relevant light-curing conditions. METHODS Two RBCs (Venus and Venus Pearl; Kulzer) that use different monomer and photo-initiator systems, but have a similar filler volume and shade, were exposed to either just blue light, or violet and blue light from two different LCUs (Translux Wave and Translux 2Wave; Kulzer). Distance and exposure times were adjusted so that both LCUs delivered 5 similar levels of radiant exposures (RE) between 1.5 J/cm²-25 J/cm² in the blue wavelength range. Thus, the violet light was additional light. The top and bottom of 2-mm thick specimens were subjected to a depth-sensing indentation test (Martens hardness/HM, Vickers hardness/HV, indentation modulus/YHU, mechanical work/Wtotal, plastic deformation work/Wplas, creep/Cr). The viability of human gingival fibroblasts was assessed after three days of exposure to RBC eluates. One and multiple-way analysis of variance (ANOVA), the Tukey honestly significant difference (HSD) post-hoc tests (α = 0.05), t-test and a Spearman correlation analysis were used. RESULTS As the RE increased, the mechanical properties increased at a greater rate at the top compared to the bottom of the RBCs. Values measured at the bottom of 2-mm increments approached the values measured at the top only when RE > 25 J/cm² of blue light was delivered. Toxicity decreased with RE and elution cycles and was lower for Venus Pearl. Within one RE level, addition of violet light resulted in significantly improved properties (in 131 out of 150 comparisons, p < 0.05). This effect was stronger for Venus Pearl. There was a good correlation between mechanical and biological parameters. This correlation decreased as the number of eluates increased. CLINICAL SIGNIFICANCE The mechanical and biological response to variation in RE is interrelated. The addition of violet light has a positive effect, particularly at low RE.
Collapse
|
4
|
Jerman E, Lümkemann N, Eichberger M, Zoller C, Nothelfer S, Kienle A, Stawarczyk B. Evaluation of translucency, Marten's hardness, biaxial flexural strength and fracture toughness of 3Y-TZP, 4Y-TZP and 5Y-TZP materials. Dent Mater 2021; 37:212-22. [PMID: 33267975 DOI: 10.1016/j.dental.2020.11.007] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Revised: 07/20/2020] [Accepted: 11/02/2020] [Indexed: 11/20/2022]
Abstract
OBJECTIVES Testing and comparing of different non-shaded zirconia materials (3Y-TZP, 4Y-TZP and 5Y-TZP) on optical and mechanical properties. MATERIALS AND METHODS Zirconia materials (N = 320, Opaque O, Translucent T, Extra Translucent ET, High Translucent HT) were investigated on translucency, Martens parameter, biaxial flexural strength, Chevron-Notch-Beam (CNB) fracture toughness (KIC) and grain size. The grain size was analyzed using a scanning electron microcopy (SEM). Univariate ANOVA, post-hoc Scheffé, partial eta-squared, Kolmogorov-Smirnov-, Kruskal-Wallis- and Mann-Whitney-U-tests (p < 0.05) were performed. The reliability of flexural strength was calculated with two-parametric Weibull analysis and 95 % confidence level. RESULTS The translucency of ET and HT increased with the thermo-mechanical aging (p < 0.001). The zirconia material and aging had no impact on the Martens hardness and the indentation modulus. ET showed the highest flexural strength values after initial and thermo-mechanical aging (p < 0.001 - 0.683). All four materials showed the highest flexural strength after thermo-mechanical aging after 1.2 Mio cycles. Thermo-mechanically (1.2 Mio cycles) aged HT presented the highest Weibull modulus (m = 15.0) regardless of aging. Within initial groups, T (p ≤ 0.001) showed the highest fracture toughness, followed by O (p ≤ 0.001), ET (p < 0.003) and HT (p ≤ 0.001). SIGNIFICANCE Translucency of ET and HT increases with thermo-mechanical aging. Chevron-Notch-Beam (CNB) is a valid alternative to the single-edge-V-notched beam (SEVNB) method for testing fracture toughness.
Collapse
|
5
|
Shelef Y, Bar-On B. Interfacial indentations in biological composites. J Mech Behav Biomed Mater 2020; 114:104209. [PMID: 33309000 DOI: 10.1016/j.jmbbm.2020.104209] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Revised: 11/02/2020] [Accepted: 11/11/2020] [Indexed: 10/23/2022]
Abstract
Biocomposites comprise highly stiff reinforcement elements connected by a compliant matrix material. While the interfacial elastic properties of these biocomposites play a key role in determining the mechanical properties of the entire biocomposite, these properties cannot be measured directly from standard nanomechanical experiments. Developing a method for extracting the interfacial elastic properties in biocomposites is, therefore, a major objective of cutting-edge biomaterials science. Here, using mechanical modeling and Finite-Element simulations, we analyze the interfacial force-depth relationships, stress distribution, and indentation modulus of standard nanoindentation testing in biocomposites, and we establish an analytical framework that connects these results to the elastic properties of the underlying matrix and reinforcement components. The resulting analytical framework is general and holds for a broad range of biocomposites, thus enabling a deeper understanding of the mechanical characteristics of functional interfaces in various biomaterials. Moreover, this framework can be adapted to account for synthetic, microscale, and nanoscale composite materials, and thereby promotes the development of advanced interfacial configurations with specialized mechanical capabilities.
Collapse
Affiliation(s)
- Yaniv Shelef
- Department of Mechanical Engineering, Ben-Gurion University of the Negev, Beer Sheva, 84105, Israel
| | - Benny Bar-On
- Department of Mechanical Engineering, Ben-Gurion University of the Negev, Beer Sheva, 84105, Israel.
| |
Collapse
|
6
|
Lümkemann N, Pfefferle R, Jerman E, Sener B, Stawarczyk B. Translucency, flexural strength, fracture toughness, fracture load of 3-unit FDPs, Martens hardness parameter and grain size of 3Y-TZP materials. Dent Mater 2020; 36:838-845. [PMID: 32370908 DOI: 10.1016/j.dental.2020.03.027] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Revised: 01/31/2020] [Accepted: 03/30/2020] [Indexed: 10/24/2022]
Abstract
OBJECTIVE This investigation tested pre-shaded 3Y-TZP materials on optical, mechanical and structural properties and calculated correlations between these properties. METHODS Seven A2-shaded 3Y-TZP zirconia materials were investigated on translucency (T) via UV-vis-spectrophotometer, fracture load of 3-unit FDPs (FL), biaxial flexural strength (FS), Chevron-Notch Beam (CNB), fracture toughness (KIC) and Martens parameter (hardness: HM and indentation modulus: EIT). FL, FS and KIC were measured in a universal testing machine. The grain size was evaluated by scanning electron microscopy (SEM). Data was analyzed using one-way ANOVA followed by post hoc Scheffé, Kruskal-Wallis-, Mann-Whitney-U- and Pearson-test (p<0.05). RESULTS For translucency, negative correlations were found with results of facture load (R=-0.444, p<0.001) and KIC (R=-0.503, p<0.001). While a positive correlation was found between translucency and flexural strength (R=0.238, p=0.019), between fracture load and EIT (R=0.227, p<0.029), between fracture load and KIC (R=0.362, p<0.001) as well as between fracture load and the grain size (R=0.598, p=0.007). While the grain size positively correlated with EIT (R=0.534, p=0.017) as well as EIT with HM (R=0.720, p<0.001). SIGNIFICANCE Despite of being based on the same raw material, tested zirconia materials significantly differed regarding optical, mechanical (except biaxial flexural strength and Martens hardness) and structural properties. Materials with highest optical properties were those with lowest mechanical properties (CER, COP).
Collapse
Affiliation(s)
- Nina Lümkemann
- Department of Prosthetic Dentistry, University Hospital, LMU Munich, Goethestrasse 70, 80336 Munich, Germany
| | - Regina Pfefferle
- Department of Prosthetic Dentistry, University Hospital, LMU Munich, Goethestrasse 70, 80336 Munich, Germany
| | - Eva Jerman
- Department of Prosthetic Dentistry, University Hospital, LMU Munich, Goethestrasse 70, 80336 Munich, Germany
| | - Beatrice Sener
- Periodontics and Cardiology, Clinic for Preventive Dentistry, University of Zurich, Plattenstrasse 11, 8032 Zurich, Switzerland
| | - Bogna Stawarczyk
- Department of Prosthetic Dentistry, University Hospital, LMU Munich, Goethestrasse 70, 80336 Munich, Germany.
| |
Collapse
|
7
|
Stawarczyk B, Dinse L, Eichberger M, Jungbauer R, Liebermann A. Flexural strength, fracture toughness, three-body wear, and Martens parameters of pressable lithium-X-silicate ceramics. Dent Mater 2020; 36:420-430. [PMID: 32007315 DOI: 10.1016/j.dental.2020.01.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Revised: 11/26/2019] [Accepted: 01/14/2020] [Indexed: 11/24/2022]
Abstract
OBJECTIVES To test and compare five pressable lithium-X-silicate-ceramics on their mechanical and wear properties. METHODS Specimens were pressed and prepared from: i. Amber Press (AP), ii. Celtra Press (CP), iii. Initial LiSi Press (IL), iv. Livento Press (LP), and v. IPS e.max Press (IE). Four-point flexural strength (FS), SEVNB fracture toughness (KIC), three-body wear (3BW), Martens hardness (HM) and indentation modulus (EIT) were measured. For CP, FS and HM were measured with and without additional Power Firing. Each subgroup contained 15 specimens. Data were analyzed using Kolmogorov-Smirnov, one-way ANOVA followed by Scheffé test, Kruskal-Wallis-H-, Mann-Whitney-U-, and Spearman-Rho-test (p < 0.05). The Weibull modulus was calculated using the maximum likelihood estimation method. RESULTS AP and CP presented higher FS than IL. LP presented the highest Weibull modulus. CP showed lower KIC values than AP, and AP was not significant compared to LP and IE. The most 3BW material loss was observed for CP. CP revealed higher HM values than the remaining ceramics. IL presented lower EIT compared to AP and CP. The following correlations were observed between the test parameters: 3BW with FS (r = 0.279, p = 0.015), with HM (r = -0.378, p = 0.001), and with EIT (r = -0.344, p = 0.004); EIT with FS (r = 0.203, p = 0.028); and HM with FT (r = -0.223, p = 0.027) and EIT (r = 0.884, p < 0.001). No correlations were observed between FS and KIC (r = 0.046; p = 0.346). SIGNIFICANCE AP followed by LP showed the highest and IL followed by CP the lowest properties tested. Power Firing of CP improved the flexural strength. Ceramics with high flexural strength and Martens parameters showed lower wear. Materials with high Martens hardness presented lower fracture toughness values and ones with high indentation modulus showed high flexural strength.
Collapse
Affiliation(s)
- Bogna Stawarczyk
- Department of Prosthetic Dentistry, University Hospital, LMU Munich, 80336 Munich, Germany.
| | - Lina Dinse
- Department of Prosthetic Dentistry, University Hospital, LMU Munich, 80336 Munich, Germany
| | - Marlis Eichberger
- Department of Prosthetic Dentistry, University Hospital, LMU Munich, 80336 Munich, Germany
| | - Rebecca Jungbauer
- Department of Prosthetic Dentistry, University Hospital, LMU Munich, 80336 Munich, Germany
| | - Anja Liebermann
- Department of Prosthetic Dentistry, University Hospital, LMU Munich, 80336 Munich, Germany
| |
Collapse
|
8
|
Ferreira AE, Ribeiro MR, Cramail H, Lourenço JP, Lorenzo V, Pérez E, Cerrada ML. Extraordinary mechanical performance in disentangled UHMWPE films processed by compression molding. J Mech Behav Biomed Mater 2018; 90:202-207. [PMID: 30384215 DOI: 10.1016/j.jmbbm.2018.09.035] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Revised: 09/21/2018] [Accepted: 09/24/2018] [Indexed: 11/27/2022]
Abstract
An approach to obtain disentangled ultra-high molecular weight polyethylene (UHMWPE) films is proposed using a common compression molding. For that, disentangled UHMWPE nascent powders from reactor are processed at temperatures lower than the main melting peak and at high pressure. Then, disentangled UHMWPE films obtained from homogeneous polymerization powders and from those that incorporate SBA-15 mesoporous silica can be easily achieved by this simple methodology. These disentangled UHMWPE based materials show very high crystallinity and, consequently, outstanding elastic modulus and hardness, both further increasing by presence of mesoporous SBA-15 in the hybrids.
Collapse
Affiliation(s)
- Ana E Ferreira
- Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Portugal; Laboratoire de Chimie des Polymères Organiques, UMR5629, Université Bordeaux, CNRS, INP-Bordeaux-ENSCBP, 16, Avenue Pey Berland, Pessac Cedex F-33607, France
| | - M Rosário Ribeiro
- Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Portugal.
| | - Henri Cramail
- Laboratoire de Chimie des Polymères Organiques, UMR5629, Université Bordeaux, CNRS, INP-Bordeaux-ENSCBP, 16, Avenue Pey Berland, Pessac Cedex F-33607, France
| | - João P Lourenço
- Centro de Química Estrutural, Instituto Superior Técnico, Universidade de Lisboa, Portugal; Faculdade de Ciências e Tecnologia, CIQA - Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal
| | - Vicente Lorenzo
- Grupo de Investigación "POLímeros: Caracterización y Aplicaciones" (U. A. del ICTP-CSIC), E.T.S.I. Industriales, Universidad Politécnica de Madrid, José Gutiérrez Abascal 2, 28006 Madrid, Spain
| | - Ernesto Pérez
- Instituto de Ciencia y Tecnología de Polímeros (ICTP-CSIC), Juan de la Cierva 3, 28006 Madrid, Spain
| | - Maria L Cerrada
- Instituto de Ciencia y Tecnología de Polímeros (ICTP-CSIC), Juan de la Cierva 3, 28006 Madrid, Spain.
| |
Collapse
|
9
|
Heinze K, Arnould O, Delenne JY, Lullien-Pellerin V, Ramonda M, George M. On the effect of local sample slope during modulus measurements by contact-resonance atomic force microscopy. Ultramicroscopy 2018; 194:78-88. [PMID: 30092392 DOI: 10.1016/j.ultramic.2018.07.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Revised: 07/03/2018] [Accepted: 07/22/2018] [Indexed: 11/28/2022]
Abstract
Contact-resonance atomic force microscopy (CR-AFM) is of great interest and very valuable for a deeper understanding of the mechanics of biological materials with moduli of at least a few GPa. However, sample surfaces can present a high topography range with significant slopes, where the local angle can be as large as ± 50°. The non-trivial correlation between surface slope and CR-frequency hinders a straight-forward interpretation of CR-AFM indentation modulus measurements on such samples. We aim to demonstrate the significant influence of the surface slope on the CR-frequency that is caused by the local angle between sample surface and the AFM cantilever and present a practical method to correct the measurements. Based on existing analytical models of the effect of the AFM set-up's intrinsic cantilever tilt on CR-frequencies, we compute the non-linear variation of the first two (eigen)modes CR-frequency for a large range of surface angles. The computations are confirmed by CR-AFM experiments performed on a curved surface. Finally, the model is applied to directly correct contact modulus measurements on a durum wheat starch granule as an exemplary sample.
Collapse
Affiliation(s)
- K Heinze
- L2C, University of Montpellier, CNRS, Montpellier F-34000, France; IATE, University of Montpellier, INRA, CIRAD, Montpellier SupAgro, Montpellier, France.
| | - O Arnould
- LMGC, University of Montpellier, CNRS, Montpellier, France
| | - J-Y Delenne
- IATE, University of Montpellier, INRA, CIRAD, Montpellier SupAgro, Montpellier, France
| | - V Lullien-Pellerin
- IATE, University of Montpellier, INRA, CIRAD, Montpellier SupAgro, Montpellier, France
| | - M Ramonda
- CTM-LMCP, University of Montpellier, Montpellier, France
| | - M George
- L2C, University of Montpellier, CNRS, Montpellier F-34000, France.
| |
Collapse
|
10
|
Ilie N. Sufficiency of curing in high-viscosity bulk-fill resin composites with enhanced opacity. Clin Oral Investig 2018; 23:747-755. [PMID: 29777311 DOI: 10.1007/s00784-018-2482-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Accepted: 05/02/2018] [Indexed: 11/29/2022]
Abstract
OBJECTIVES The study aims analyzing if improved opacity in modern high-viscosity bulk-fill resin composites (BF-RBC) contradicts with the sufficiency of curing and to assess material's tolerance to less ideal curing conditions. MATERIALS AND METHODS Simulated large cavities (10 × 6) mm were filled in one increment with three BF-RBCs (Filtek One, FO; Tetric Evo Ceram Bulk Fill, TEC-BF; SonicFill2, SF2). One central and two peripheral (4 mm apart from the center) micromechanical property line-profiles (HV, Vickers hardness; YHU, indentation modulus) were measured in 0.2-mm steps at 24 h post-polymerization (n = 6). Depth of cure (DOC) was calculated from the HV variation in depth. A scratch test (DOCscratch test) estimated the tolerance in polymerization when simulating clinically relevant curing conditions (exposure distance up to 7 mm; centered and with a 3-mm offset placement of the LCU). Irradiance and spectral distribution of the used light curing unit (LCU) were assessed at various curing conditions. RESULTS DOC varied among 3.6 mm (SF2, peripheral) and 5.7 mm (FO, central). The BF-RBC influences DOC stronger (p < 0.001, ηP2 = 0.616) than the width (p < 0.001, ηP2 = 0.398). Significant lower DOC (t test) was measured peripheral compared to center in all materials. YHU was more sensitive to the varied parameters as HV. DOCscratch test varied among 2.4 mm (SF2, 3-mm offset, exposure distance 7 mm) and 3.9 mm (FO, center, 0 mm). CONCLUSIONS Whether opacity competes with DOC is material dependent. BF-RBCs tolerate small variations in LCU's centricity better than variations in exposure distance. CLINICAL RELEVANCE The upper incremental thickness threshold of 4 or 5 mm was not reached in all BF-RBCs under simulated clinically relevant curing conditions.
Collapse
Affiliation(s)
- Nicoleta Ilie
- Department of Operative Dentistry and Periodontology, University Hospital, Ludwig-Maximilians-Universität München, Goethestr. 70, 80336, Munich, Germany.
| |
Collapse
|
11
|
Casdorff K, Keplinger T, Rüggeberg M, Burgert I. A close-up view of the wood cell wall ultrastructure and its mechanics at different cutting angles by atomic force microscopy. Planta 2018; 247:1123-1132. [PMID: 29380141 DOI: 10.1007/s00425-018-2850-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Accepted: 01/13/2018] [Indexed: 06/07/2023]
Abstract
AFM measurements on spruce sample cross-sections reveal that the structural appearance of the S2 layer changes from a network structure to a concentric lamellar texture depending on the cutting angle. The structural assembly of wood constituents within the secondary cell wall has been subject of numerous studies over the last decades, which has resulted in contradicting models on the spatial arrangement and orientation of the wood macromolecules. Here, we use multichannel atomic force microscopy by means of quantitative imaging, to gain new insights into the macromolecular assembly. Cross-sections of spruce wood, which had been cut at different angles ranging from 0° to 30° were investigated. Strikingly, depending on the cutting angle, the structural appearance of the S2 layer changed from a network-like structure to a distinct concentric lamellar texture. This makes us conclude that the often visualized lamellar organization of the secondary cell wall is not the consequence of a continuous inherent ring pattern, but rather a result of the specific surface cross-section appearance of cellulose aggregates at larger cutting angles. By analyzing the recorded force distance curves in every pixel, a nano-mechanical characterization of the secondary cell wall was conducted. Substantially lower indentation modulus values were obtained compared to nanoindentation values reported in the literature. This is potentially due to a smaller interaction volume of the probe with a by far less deep indentation.
Collapse
Affiliation(s)
- Kirstin Casdorff
- Wood Materials Science, Institute for Building Materials, ETH Zürich, Stefano-Franscini-Platz 3, 8093, Zurich, Switzerland.
- Applied Wood Materials, Empa-Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, 8600, Dübendorf, Switzerland.
| | - Tobias Keplinger
- Wood Materials Science, Institute for Building Materials, ETH Zürich, Stefano-Franscini-Platz 3, 8093, Zurich, Switzerland
- Applied Wood Materials, Empa-Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, 8600, Dübendorf, Switzerland
| | - Markus Rüggeberg
- Wood Materials Science, Institute for Building Materials, ETH Zürich, Stefano-Franscini-Platz 3, 8093, Zurich, Switzerland
- Applied Wood Materials, Empa-Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, 8600, Dübendorf, Switzerland
| | - Ingo Burgert
- Wood Materials Science, Institute for Building Materials, ETH Zürich, Stefano-Franscini-Platz 3, 8093, Zurich, Switzerland
- Applied Wood Materials, Empa-Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, 8600, Dübendorf, Switzerland
| |
Collapse
|
12
|
Zoergiebel J, Ilie N. An in vitro study on the maturation of conventional glass ionomer cements and their interface to dentin. Acta Biomater 2013; 9:9529-37. [PMID: 23954325 DOI: 10.1016/j.actbio.2013.08.010] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2013] [Revised: 08/05/2013] [Accepted: 08/07/2013] [Indexed: 11/29/2022]
Abstract
The objective of the study was to investigate the influence of long-term storage (up to 1 year) and coating on the variation of micro-mechanical properties of four conventional restorative glass ionomer cements (GICs) within 3.5 mm deep class I cavities. Four commercially available GICs (Riva Self Cure (SDI), ChemFil Rock (Dentsply), Fuji IX Fast and Fuji IX GP Extra/Equia (GC)) were applied to 100 teeth. In each tooth, two similar 3.5 mm deep class I cavities were prepared and filled with the GICs, with and without resin coating. The samples were stored in artificial saliva at 37 °C for 1 week, 1 month, 3 months, 6 months and 1 year. The variation in mechanical properties (indentation modulus (E) and Vickers hardness (HV)) were determined in 100 μm steps starting from the filling surface, through the intermediate layer in between dentine and GIC, and ending 100 μm in dentin. HV and E were strongly influenced by the material (P<0.05, partial eta-squared ηP(2) = 0.31 and 0.23) but less by aging duration (P<0.05, ηP(2) = 0.02 and 0.12) and resin coating (P<0.05, ηP(2) = 0.02 and 0.03). The depth of measurement (0-2 mm) has no influence on HV (P = 0.789). HV shows a gentle increase over the 1 year storage period (P = 0.002). A ∼300 μm GIC zone at the areas close to dentin with weaker properties as those measured in dentin or GIC was identified in all fillings, irrespective of the presence of coating, and at all storage periods. The thickness of this zone is more strongly influenced by storage (P<0.05, ηP(2) = 0.081) than by material type (P<0.05, ηP(2) = 0.056), while coating showed no influence (P = 0.869). Filler morphology and dimension were similar to upper parts of the GIC filling; however, the amount of low cations was higher. We concluded that the development of an intermediate layer in between dentine and GIC with lower mechanical properties might be responsible for the bond quality of GIC to dentine. Moreover, class I GIC restorations are unlikely to feature constant mechanical properties throughout the cavity, regardless of conditions such as aging and coating.
Collapse
Affiliation(s)
- Julius Zoergiebel
- Department of Operative/Restorative Dentistry, Periodontology and Pedodontics, Ludwig-Maximilians-University of Munich, Goethestr. 70, 80336 Munich, Germany
| | | |
Collapse
|