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Tiu J, Belli R, Lohbauer U. A step toward bio-inspired dental composites. Biomater Investig Dent 2023; 10:1-7. [PMID: 36684391 PMCID: PMC9858410 DOI: 10.1080/26415275.2022.2150625] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
This feasibility study aimed to develop a new composite material of aligned glass flakes in a polymer resin matrix inspired by the biological composite nacre. The experimental composite was processed by an adapted method of pressing a glass flake and resin monomer system. By pressing and allowing the excess monomer to flow out, the long axis of the flakes was aligned. The resultant anisotropic composite with silanized and non-silanized glass flakes were subjected to fracture toughness tests. We observed increasing fracture toughness with increasing crack extension (Δa) known as resistance curve (R-curve) behavior. Silanized specimens had higher stress intensity KR-Δa over non-silanized specimens, whereas non-silanized specimens had a much lower Young's modulus, and higher nonlinear plastic-elastic JR-Δa R-curve. In comparison with conventional composites, flake-reinforced composites can sustain continued crack growth for more significant extensions. The primary toughening mechanism seen in flake-reinforced composites was crack deviation and crack branching. We produced an anisotropic model of glass flake-reinforced composite showing elevated toughening potential and a prominent R-curve effect. The feasibility of flake reinforcement of dental composites has been shown using a relatively efficient method. The use of a biomimetic, nacre-inspired reinforcement concept might guide further research toward improvement of dental restorative materials.
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Affiliation(s)
- Janine Tiu
- Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Zahnklinik 1 – Zahnerhaltung und Parodontologie, Forschungslabor für dentale Biomaterialien, Erlangen, Germany
| | - Renan Belli
- Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Zahnklinik 1 – Zahnerhaltung und Parodontologie, Forschungslabor für dentale Biomaterialien, Erlangen, Germany
| | - Ulrich Lohbauer
- Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Zahnklinik 1 – Zahnerhaltung und Parodontologie, Forschungslabor für dentale Biomaterialien, Erlangen, Germany,CONTACT Ulrich Lohbauer Research Laboratory for Dental Biomaterials, Dental Clinic 1 – Operative Dentistry and Periodontology, Glueckstrasse 11 D-91054Erlangen, Germany
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A split-Chevron-Notched-Beam sandwich specimen for fracture toughness testing of bonded interfaces. J Mech Behav Biomed Mater 2022; 131:105236. [DOI: 10.1016/j.jmbbm.2022.105236] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Revised: 04/06/2022] [Accepted: 04/10/2022] [Indexed: 11/22/2022]
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Mechanical degradation of contemporary CAD/CAM resin composite materials after water ageing. Dent Mater 2021; 37:1156-1167. [PMID: 33933272 DOI: 10.1016/j.dental.2021.04.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 03/29/2021] [Accepted: 04/08/2021] [Indexed: 11/22/2022]
Abstract
OBJECTIVE The aim of the present study was to assess the effect of water storage on the quasi-static properties and cyclic fatigue behavior of four contemporary CAD/CAM resin composite materials. METHODS The CAD/CAM resin composites Grandio Blocs, LavaTM Ultimate, CerasmartTM and Brilliant Crios, as well as the direct resin composite Grandio SO, were evaluated. Rectangular plates were cut from the blocks or fabricated using a silicon mold to obtain specimens for fracture toughness (KIc, n = 10), biaxial strength (σ0, n = 30) and cyclic fatigue testing (n = 30). Half of the specimens was stored for 24 h in dry conditions and the other half was aged for 60 days in distilled water at 37 °C. KIc was determined using the Compact-Tension (C(T)) method and σ0 and cyclic fatigue were tested using the Ball-on-Three-Balls assembly. Additional disc-shaped specimens (n = 5) were produced to obtain water sorption curves of the materials. Weibull statistics and two-way ANOVA with Tukey's post-hoc test were used for data assessment. RESULTS The highest water sorption was observed for LavaTM Ultimate (42.6 μg/mm3), whereas Grandio SO displayed the lowest uptake (14 μg/mm3). A statistically significant drop in KIc and σ0 was measured for all materials after water storage, except for the σ0 of CerasmartTM. Water ageing had a dissimilar effect on the cyclic fatigue behavior, increasing the slow crack growth susceptibility of LavaTM Ultimate, but decreasing it for CerasmartTM and Brilliant Crios. SIGNIFICANCE Contemporary CAD/CAM resin composites are susceptible to water driven degradative processes, although differences in filler content and resin matrix constitution play an important role in how it impacts their mechanical properties.
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Improved Fracture Toughness and Conversion Degree of Resin-Based Dental Composites after Modification with Liquid Rubber. MATERIALS 2020; 13:ma13122704. [PMID: 32545845 PMCID: PMC7344604 DOI: 10.3390/ma13122704] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 06/05/2020] [Accepted: 06/11/2020] [Indexed: 11/17/2022]
Abstract
There are many methods widely applied in the engineering of biomaterials to improve the mechanical properties of the dental composites. The aim of this study was to assess the effect of modification of dental composites with liquid rubber on their mechanical properties, degree of conversion, viscosity, and cytotoxicity. Both flow and packable composite consisted of a mixture of Bis-GMA, TEGDMA, UDMA, and EBADMA resins reinforced with 60 and 78 wt.% ceramic filler, respectively. It was demonstrated that liquid rubber addition significantly increased the fracture toughness by 9% for flow type and 8% for condensable composite. The influence of liquid rubber on flexural strength was not statistically significant. The addition of the toughening agent significantly reduced Young’s modulus by 7% and 9%, respectively, while increasing deformation at breakage. Scanning electron microscopy (SEM) observations allowed to determine the mechanisms of toughening the composites reinforced with ceramic particles. These mechanisms included bridging the crack edges, blocking the crack tip by particles and dissipation of fracture energy by deflection of the cracks on larger particles. The degree of conversion increased after modification, mainly due to a decrease in the matrix resin viscosity. It was also shown that all dental materials were nontoxic according to ISO 10993-5, indicating that modified materials have great potential for commercialization and clinical applications.
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Shah S, Shilpa-Jain D, Velmurugan N, Sooriaprakas C, Krithikadatta J. Performance of fibre reinforced composite as a post-endodontic restoration on different endodontic cavity designs— an in-vitro study. J Mech Behav Biomed Mater 2020; 104:103650. [DOI: 10.1016/j.jmbbm.2020.103650] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Revised: 01/18/2020] [Accepted: 01/21/2020] [Indexed: 12/13/2022]
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Rising R-curves in particulate/fiber-reinforced resin composite layered systems. J Mech Behav Biomed Mater 2020; 103:103537. [DOI: 10.1016/j.jmbbm.2019.103537] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Revised: 11/05/2019] [Accepted: 11/14/2019] [Indexed: 11/17/2022]
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Tiu J, Belli R, Lohbauer U. R-curve behavior of a short-fiber reinforced resin composite after water storage. J Mech Behav Biomed Mater 2020; 104:103674. [PMID: 32174430 DOI: 10.1016/j.jmbbm.2020.103674] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 02/03/2020] [Accepted: 02/04/2020] [Indexed: 10/25/2022]
Abstract
As a supplement to our investigation into R-curves in a short-fiber reinforced dental resin composite, we investigate the effects of 2-months water storage. Water is known to degrade the siloxane bonds linking matrix and fillers, which has been suggested to decrease the fracture toughness in conventional resin composites. However, fiber-reinforced systems seem to be less affected as the toughness is dependent on fiber bridging, which is only effective if a weaker interfacial bond between fiber and matrix is present.
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Affiliation(s)
- Janine Tiu
- Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Zahnklinik 1 - Zahnerhaltung und Paradontlogie, Forschungslabor für dentale Biomaterialien, Glueckstrasse 11, Erlangen 91054, Germany.
| | - Renan Belli
- Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Zahnklinik 1 - Zahnerhaltung und Paradontlogie, Forschungslabor für dentale Biomaterialien, Glueckstrasse 11, Erlangen 91054, Germany.
| | - Ulrich Lohbauer
- Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Zahnklinik 1 - Zahnerhaltung und Paradontlogie, Forschungslabor für dentale Biomaterialien, Glueckstrasse 11, Erlangen 91054, Germany.
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Kruzic JJ, Arsecularatne JA, Tanaka CB, Hoffman MJ, Cesar PF. Recent advances in understanding the fatigue and wear behavior of dental composites and ceramics. J Mech Behav Biomed Mater 2018; 88:504-533. [PMID: 30223214 DOI: 10.1016/j.jmbbm.2018.08.008] [Citation(s) in RCA: 75] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Revised: 08/06/2018] [Accepted: 08/08/2018] [Indexed: 12/30/2022]
Abstract
Dental composite and ceramic restorative materials are designed to closely mimic the aesthetics and function of natural tooth tissue, and their longevity in the oral environment depends to a large degree on their fatigue and wear properties. The purpose of this review is to highlight some recent advances in our understanding of fatigue and wear mechanisms, and how they contribute to restoration failures in the complex oral environment. Overall, fatigue and wear processes are found to be closely related, with wear of dental ceramic occlusal surfaces providing initiation sites for fatigue failures, and subsurface fatigue crack propagation driving key wear mechanisms for composites, ceramics, and enamel. Furthermore, both fatigue and wear of composite restorations may be important in enabling secondary caries formation, which is the leading cause of composite restoration failures. Overall, developing a mechanistic description of fatigue, wear, and secondary caries formation, along with understanding the interconnectivity of all three processes, are together seen as essential keys to successfully using in vitro studies to predict in vivo outcomes and develop improved dental restorative materials.
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Affiliation(s)
- Jamie J Kruzic
- School of Mechanical and Manufacturing Engineering, UNSW Sydney, Sydney, NSW 2052, Australia.
| | | | - Carina B Tanaka
- School of Mechanical and Manufacturing Engineering, UNSW Sydney, Sydney, NSW 2052, Australia
| | - Mark J Hoffman
- School of Mechanical and Manufacturing Engineering, UNSW Sydney, Sydney, NSW 2052, Australia; School of Materials Science and Engineering, UNSW Sydney, Sydney, NSW 2052, Australia
| | - Paulo F Cesar
- Department of Biomaterials and Oral Biology, School of Dentistry, University of São Paulo, São Paulo, Brazil
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Belli R, Wendler M, Zorzin JI, Lohbauer U. Practical and theoretical considerations on the fracture toughness testing of dental restorative materials. Dent Mater 2017; 34:97-119. [PMID: 29203072 DOI: 10.1016/j.dental.2017.11.016] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Revised: 11/13/2017] [Accepted: 11/13/2017] [Indexed: 11/19/2022]
Abstract
BACKGROUND An important tool in materials research, development and characterization regarding mechanical performance is the testing of fracture toughness. A high level of accuracy in executing this sort of test is necessary, with strict requirements given in extensive testing standard documents. Proficiency in quality specimen fabrication and test requires practice and a solid theoretical background, oftentimes overlooked in the dental community. AIMS In this review we go through some fundamentals of the fracture mechanics concepts that are relevant to the understanding of fracture toughness testing, and draw attention to critical aspects of practical nature that must be fulfilled for validity and accuracy in results. We describe our experience with some testing methodologies for CAD/CAM materials and discuss advantages and shortcomings of different tests in terms of errors in testing the applicability of the concept of fracture toughness as a single-value material-specific property.
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Affiliation(s)
- Renan Belli
- Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Zahnklinik 1 - Zahnerhaltung und Parodontologie, Forschungslabor für dentale Biomaterialien, Glueckstrasse 11, 91054 Erlangen, Germany.
| | - Michael Wendler
- Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Zahnklinik 1 - Zahnerhaltung und Parodontologie, Forschungslabor für dentale Biomaterialien, Glueckstrasse 11, 91054 Erlangen, Germany; Department of Restorative Dentistry, Faculty of Dentistry, University of Concepción, Concepción, Chile
| | - José I Zorzin
- Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Zahnklinik 1 - Zahnerhaltung und Parodontologie, Forschungslabor für dentale Biomaterialien, Glueckstrasse 11, 91054 Erlangen, Germany
| | - Ulrich Lohbauer
- Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Zahnklinik 1 - Zahnerhaltung und Parodontologie, Forschungslabor für dentale Biomaterialien, Glueckstrasse 11, 91054 Erlangen, Germany
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10
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ADM guidance-ceramics: Fatigue principles and testing. Dent Mater 2017; 33:1192-1204. [DOI: 10.1016/j.dental.2017.09.006] [Citation(s) in RCA: 77] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Accepted: 09/15/2017] [Indexed: 11/19/2022]
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Meng H, Sun Z, Jiang R, Zhang C. Measuring the adherence energy of the resin-metal interface with two fracture mechanics methods: The DCB and NTP tests. Biomed Mater Eng 2015; 26:149-60. [PMID: 26684887 DOI: 10.3233/bme-151562] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
OBJECTIVE To evaluate the abilities of the DCB and the NTP test for measuring adherence of an adhesive joint between a resin and a metal interface. METHODS Two-hundred stainless steel metal beams (diam. 50×5×2 mm) were cast and treated by the following methods: (1) sandblasting with aluminum oxide, followed by treatment with (2) the Rocatec system or (3) the Alloy primer. Superbond and Panavia F 2.0 were used as adhesives. The fracture energy (G1C) and fracture toughness (K1C) of two adhesives were compared by two-way analysis of variance. RESULTS With the DCB test, Superbond was more effective than Panavia, regardless of the surface treatment and conditions of crack propagation. The overall effectiveness of the treatments was in the following order: sandblasting + Rocatec > sandblasting alone > sandblasting + Alloy primer. The adherence energy in an aqueous medium was lower than that in air. With the NTP test, similar performances were obtained with three surface treatments. However, the potential of Rocatec seemed slightly higher. CONCLUSIONS The DCB and NTP tests provide independent measures of the inherent value of an adhesive. Rocatec appeared to provide greater resistance of the bonded joints in an aqueous environment.
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Affiliation(s)
- HongMei Meng
- Department of Neurology, The First Hospital of JiLin University, 71 XinMin Street, ChangChun 130021, China
| | - ZhiGuang Sun
- Department of Stomatology, JiLin Province Hospital, 1183 GongNong Road, ChangChun 130021, China
| | - RiWen Jiang
- Department of Stomatology, 461 Outpatient Department, 208 Military Hospital, 108 ZiYou Road, ChangChun 130021, China
| | - CongXiao Zhang
- Department of Stomatology, The First Hospital of JiLin University, 71 XinMin Street, ChangChun 130021, China
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Yahyazadehfar M, Ivancik J, Majd H, An B, Zhang D, Arola D. On the Mechanics of Fatigue and Fracture in Teeth. APPLIED MECHANICS REVIEWS 2014; 66:0308031-3080319. [PMID: 25516632 PMCID: PMC4240032 DOI: 10.1115/1.4027431] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2013] [Revised: 03/30/2014] [Indexed: 05/24/2023]
Abstract
Tooth fracture is a major concern in the field of restorative dentistry. However, knowledge of the causes for tooth fracture has developed from contributions that are largely based within the field of mechanics. The present manuscript presents a technical review of advances in understanding the fracture of teeth and the fatigue and fracture behavior of their hard tissues (i.e., dentin and enamel). The importance of evaluating the fracture resistance of these materials, and the role of applied mechanics in developing this knowledge will be reviewed. In addition, the complex microstructures of tooth tissues, their roles in resisting tooth fracture, and the importance of hydration and aging on the fracture resistance of tooth tissues will be discussed. Studies in this area are essential for increasing the success of current treatments in dentistry, as well as in facilitating the development of novel bio-inspired restorative materials for the future.
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Affiliation(s)
- Mobin Yahyazadehfar
- Department of Mechanical Engineering,
University of Maryland Baltimore County,
Baltimore, MD 21250
| | - Juliana Ivancik
- Department of Mechanical Engineering,
University of Maryland Baltimore County,
Baltimore, MD 21250
- Protective Equipment Division,
U.S Army Aberdeen Test Center,
Aberdeen, MD 21001
| | - Hessam Majd
- Department of Mechanical Engineering,
University of Maryland Baltimore County,
Baltimore, MD 21250
| | - Bingbing An
- Department of Mechanics,
Shanghai University,
Shanghai 200444, China
- Shanghai Key Laboratory of
Mechanics in Energy Engineering,
Shanghai 200072, China
| | - Dongsheng Zhang
- Department of Mechanics,
Shanghai University,
Shanghai 200444, China
- Shanghai Key Laboratory of
Mechanics in Energy Engineering,
Shanghai 200072, China
| | - Dwayne Arola
- Department of Materials Science
and Engineering,
University of Washington,
Seattle, WA 98195
- Department of Endodontics,
Prosthodontics, and Operative Dentistry,
Dental School,
University of Maryland,
Baltimore, MD 21201
e-mail:
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Belli R, Geinzer E, Muschweck A, Petschelt A, Lohbauer U. Mechanical fatigue degradation of ceramics versus resin composites for dental restorations. Dent Mater 2014; 30:424-32. [DOI: 10.1016/j.dental.2014.01.003] [Citation(s) in RCA: 87] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2013] [Revised: 09/20/2013] [Accepted: 01/14/2014] [Indexed: 02/04/2023]
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Belli R, Petschelt A, Lohbauer U. Are linear elastic material properties relevant predictors of the cyclic fatigue resistance of dental resin composites? Dent Mater 2014; 30:381-91. [DOI: 10.1016/j.dental.2014.01.009] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2013] [Revised: 08/30/2013] [Accepted: 01/14/2014] [Indexed: 11/17/2022]
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Yahyazadehfar M, Nazari A, Kruzic JJ, Quinn GD, Arola D. An inset CT specimen for evaluating fracture in small samples of material. J Mech Behav Biomed Mater 2014; 30:358-68. [PMID: 24268892 PMCID: PMC4059206 DOI: 10.1016/j.jmbbm.2013.10.017] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Revised: 10/15/2013] [Accepted: 10/19/2013] [Indexed: 11/26/2022]
Abstract
In evaluations on the fracture behavior of hard tissues and many biomaterials, the volume of material available to study is not always sufficient to apply a standard method of practice. In the present study an inset Compact Tension (inset CT) specimen is described, which uses a small cube of material (approximately 2×2×2mm(3)) that is molded within a secondary material to form the compact tension geometry. A generalized equation describing the Mode I stress intensity was developed for the specimen using the solutions from a finite element model that was defined over permissible crack lengths, variations in specimen geometry, and a range in elastic properties of the inset and mold materials. A validation of the generalized equation was performed using estimates for the fracture toughness of a commercial dental composite via the "inset CT" specimen and the standard geometry defined by ASTM E399 (2006). Results showed that the average fracture toughness obtained from the new specimen (1.23±0.02MPam(0.5)) was within 2% of that from the standard. Applications of the inset CT specimen are presented for experimental evaluations on the crack growth resistance of dental enamel and root dentin, including their fracture resistance curves. Potential errors in adopting this specimen are then discussed, including the effects of debonding between the inset and molding material on the estimated stress intensity distribution. Results of the investigation show that the inset CT specimen offers a viable approach for studying the fracture behavior of small volumes of structural materials.
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Affiliation(s)
- M Yahyazadehfar
- University of Maryland Baltimore County, Department of Mechanical Engineering, 1000 Hilltop Circle, Baltimore, MD 21250, USA
| | - A Nazari
- University of Maryland Baltimore County, Department of Mechanical Engineering, 1000 Hilltop Circle, Baltimore, MD 21250, USA
| | - J J Kruzic
- Materials Science, School of Mechanical(,) Industrial, and Manufacturing Engineering, Oregon State University, Corvallis, OR, 97331, USA
| | - G D Quinn
- University of Maryland Baltimore County, Department of Mechanical Engineering, 1000 Hilltop Circle, Baltimore, MD 21250, USA
| | - D Arola
- University of Maryland Baltimore County, Department of Mechanical Engineering, 1000 Hilltop Circle, Baltimore, MD 21250, USA; Department of Endodontics, Prosthodontics, and Operative Dentistry, Baltimore College of Dental Surgery, University of Maryland, Baltimore, MD 21201, USA.
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Khvostenko D, Mitchell JC, Hilton TJ, Ferracane JL, Kruzic JJ. Mechanical performance of novel bioactive glass containing dental restorative composites. Dent Mater 2013; 29:1139-48. [PMID: 24050766 DOI: 10.1016/j.dental.2013.08.207] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Revised: 08/14/2013] [Accepted: 08/18/2013] [Indexed: 01/31/2023]
Abstract
OBJECTIVES Bioactive glass (BAG) is known to possess antimicrobial properties and release ions needed for remineralization of tooth tissue, and therefore may be a strategic additive for dental restorative materials. The objective of this study was to develop BAG containing dental restorative composites with adequate mechanical properties comparable to successful commercially available composites, and to confirm the stability of these materials when exposed to a biologically challenging environment. METHODS Composites with 72 wt% total filler content were prepared while substituting 0-15% of the filler with ground BAG. Flexural strength, fracture toughness, and fatigue crack growth tests were performed after several different soaking treatments: 24h in DI water (all experiments), two months in brain-heart infusion (BHI) media+Streptococcus mutans bacteria (all experiments) and two months in BHI media (only for flexural strength). Mechanical properties of new BAG composites were compared along with the commercial composite Heliomolar by two-way ANOVA and Tukey's multiple comparison test (p≤0.05). RESULTS Flexural strength, fracture toughness, and fatigue crack growth resistance for the BAG containing composites were unaffected by increasing BAG content up to 15% and were superior to Heliomolar after all post cure treatments. The flexural strength of the BAG composites was unaffected by two months exposure to aqueous media and a bacterial challenge, while some decreases in fracture toughness and fatigue resistance were observed. The favorable mechanical properties compared to Heliomolar were attributed to higher filler content and a microstructure morphology that better promoted the toughening mechanisms of crack deflection and bridging. SIGNIFICANCE Overall, the BAG containing composites developed in this study demonstrated adequate and stable mechanical properties relative to three successful commercial composites.
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Affiliation(s)
- D Khvostenko
- School of Mechanical, Industrial, and Manufacturing Engineering, Oregon State University, Corvallis, OR, USA
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Lohbauer U, Belli R, Ferracane J. Factors Involved in Mechanical Fatigue Degradation of Dental Resin Composites. J Dent Res 2013; 92:584-91. [DOI: 10.1177/0022034513490734] [Citation(s) in RCA: 98] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The design of clinical trials allows for limited insights into the fatigue processes occurring in resin composites and the factors involved therein. In vitro studies, in contrast, can fundamentally narrow study interests to focus on particular degradation mechanisms and, to date, represent the major contributors to the state of knowledge on the subject. These studies show that microstructural features are important in determining strength and fracture toughness, whereas fatigue resistance is mainly related to the susceptibility of the matrix and the filler/matrix interface to mechanical and chemical degradation. In this review, we focus on fracture mechanisms occurring during fatigue, on the methods used to assess them, and on additional phenomena involved in the degradation of initial mechanical properties of resin composites.
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Affiliation(s)
- U. Lohbauer
- Laboratory for Biomaterials Research, Dental Clinic 1 – Operative Dentistry and Periodontology, University of Erlangen-Nuremberg, Glueckstrasse 11, 91054 Erlangen, Germany
| | - R. Belli
- Laboratory for Biomaterials Research, Dental Clinic 1 – Operative Dentistry and Periodontology, University of Erlangen-Nuremberg, Glueckstrasse 11, 91054 Erlangen, Germany
| | - J.L. Ferracane
- Division of Biomaterials & Biomechanics, Department of Restorative Dentistry, School of Dentistry, Oregon Health & Science University, Portland, OR 97239, USA
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Dastjerdi AK, Pagano M, Kaartinen MT, McKee MD, Barthelat F. Cohesive behavior of soft biological adhesives: experiments and modeling. Acta Biomater 2012; 8:3349-59. [PMID: 22588071 DOI: 10.1016/j.actbio.2012.05.005] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2012] [Revised: 04/18/2012] [Accepted: 05/08/2012] [Indexed: 01/26/2023]
Abstract
Extracellular proteins play a key role in generating and maintaining cohesion and adhesion in biological tissues. These "natural glues" are involved in vital biological processes such as blood clotting, wound healing and maintaining the structural integrity of tissues. Macromolecular assemblies of proteins can be functionally stabilized in a variety of ways in situ that include ionic interactions as well as covalent crosslinking to form protein networks that can extend both within and between tissues. Within tissues, myriad cohesive forces are required to preserve tissue integrity and function, as are additional appropriate adhesive forces at interfaces both within and between tissues of differing composition. While the mechanics of some key structural adhesive proteins have been characterized in tensile experiments at both the macroscopic and single protein levels, the fracture toughness of thin proteinaceous interfaces has never been directly measured. Here, we describe a novel and simple approach to measure the cohesive behavior and toughness of thin layers of proteinaceous adhesives. The test is based on the standard double-cantilever beam test used for engineering adhesives, which was adapted to take into account the high compliance of the interface compared with the beams. This new "rigid double-cantilever beam" method enables stable crack propagation through an interfacial protein layer, and provides a direct way to measure its full traction-separation curve. The method does not require any assumption of the shape of the cohesive law, and the results provide abundant information contributing to understanding the structural, chemical and molecular mechanisms acting in biological adhesion. As an example, results are presented using this method for thin films of fibrin-a protein involved in blood clotting and used clinically as a tissue bio-adhesive after surgery-with the effects of calcium and crosslinking by Factor XIII being examined. Finally, a simple model is proposed, demonstrating how a bell-shaped cohesive law forms during the failure of the fibrin interface based on an eight-chain model whose structure degrades and changes configuration with stress.
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Affiliation(s)
- A Khayer Dastjerdi
- Department of Mechanical Engineering, McGill University, 817 Sherbrooke Street West, Montreal, Quebec, Canada H3A 2K6
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Ornaghi BP, Meier MM, Rosa V, Cesar PF, Lohbauer U, Braga RR. Subcritical crack growth and in vitro lifetime prediction of resin composites with different filler distributions. Dent Mater 2012; 28:985-95. [DOI: 10.1016/j.dental.2012.05.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2011] [Revised: 04/25/2012] [Accepted: 05/01/2012] [Indexed: 10/28/2022]
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