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Carrillo-Cotto R, da Silva AF, Isolan CP, Selayaran RPG, Selayaran M, Lima FG, Münchow EA. Effects of alternatively used thermal treatments on the mechanical and fracture behavior of dental resin composites with varying filler content. J Mech Behav Biomed Mater 2021; 117:104424. [PMID: 33652234 DOI: 10.1016/j.jmbbm.2021.104424] [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] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 01/13/2021] [Accepted: 02/21/2021] [Indexed: 11/19/2022]
Abstract
The purpose of this study was two-fold: (i) to investigate whether the thermal treatment of direct dental resin composites (RCs) using microwave or autoclave heating cycles would modify the materials' strength as compared to the protocol without heating (control); and (ii) to compare the mechanical performance of direct and indirect RCs. Three RCs (from 3M ESPE) were tested: one indirect (Sinfony); and two direct materials (microhybrid - Filtek Z250; and nanofilled - Filtek Z350). Specimens from the direct RCs were prepared and randomly allocated into three groups according to the thermal treatment (n = 10): Control - no thermal treatment was performed; Microwave - the wet heating was performed using a microwave oven; and Autoclave - the wet heating was performed in an autoclave oven. The indirect RC was prepared following the instructions of the manufacturer. All materials were tested using flexural strength, elastic modulus, work of fracture (Wf), microhardness, and scanning electron microscopy (SEM) analyses. Data were analyzed with ANOVA and Tukey as well as Weibull analysis (α = 0.05). The thermal treatments tended to produce slight changes in the topography of direct RCs, especially by the autoclave' wet heating. Overall, the physico-mechanical properties changed after thermal treatment, although this effect was dependent on the type of RC and on the heating protocol. Sinfony showed the lowest modulus and hardness of the study, although it was the most compliant system (higher work of fracture). The load-deflection ability was also greater for the indirect RC. Reliability of the tested materials was similar among each other (p > 0.05). In conclusion, the alternative thermal treatments suggested here may significantly influence some aspects of the mechanical behavior of dental resin composites, with negative effects relying on both the chemical composition of the restorative material as well as on the wet heating protocol used. Clinicians should be aware of the possible effects that additional wet heating of direct resin composites using microwave or autoclave thermal protocols as performed here could have on the overall fracture and mechanical responses during loading circumstances.
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Affiliation(s)
- Ricardo Carrillo-Cotto
- Department of Restorative Dentistry and Dental Biomaterials, School of Dentistry, University of San Carlos of Guatemala, Guatemala City, Guatemala; Graduate Program in Dentistry, School of Dentistry, Federal University of Pelotas, Pelotas, RS, Brazil
| | - Adriana F da Silva
- Graduate Program in Dentistry, School of Dentistry, Federal University of Pelotas, Pelotas, RS, Brazil
| | - Cristina P Isolan
- Graduate Program in Dentistry, School of Dentistry, Federal University of Pelotas, Pelotas, RS, Brazil
| | - Raquel P G Selayaran
- Center for the Development and Control of Biomaterials, Federal University of Pelotas, Pelotas, RS, Brazil
| | - Maicon Selayaran
- Center for the Development and Control of Biomaterials, Federal University of Pelotas, Pelotas, RS, Brazil
| | - Fábio G Lima
- Graduate Program in Dentistry, School of Dentistry, Federal University of Pelotas, Pelotas, RS, Brazil
| | - Eliseu A Münchow
- Department of Conservative Dentistry, School of Dentistry, Federal University of Rio Grande do Sul, Porto Alegre, RS, Brazil; Graduate Program in Dentistry, Federal University of Rio Grande do Sul, Porto Alegre, RS, Brazil.
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Currey JD, Brear K, Zioupos P. Strain rate dependence of work of fracture tests on bone and similar tissues: Reflections on testing methods and mineral content effects. Bone 2019; 128:115038. [PMID: 31446116 DOI: 10.1016/j.bone.2019.115038] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Revised: 08/15/2019] [Accepted: 08/15/2019] [Indexed: 11/15/2022]
Abstract
This paper is concerned with the effect of different strain rate on the Work of Fracture (Wf) of various vertebrate mineralised tissues, controlling for the effect of mineral content and Young's modulus of elasticity. Using specimens of uniform shape and size values for the Work of Fracture of specimens tested at various deformation rates, and also the energy absorbed by notched specimens in impact, are reported. The results indicated that, of those tested, for most bone specimens the Work of Fracture measurements were constant like in the case for a 'material property'. Variations due to loading conditions (deformation rate) were small, with the exemption of antler, which is relatively poorly mineralised and in which the Work of Fracture values increased by a factor of 4 across the range from quasistatic loading to impact. The Tattersall and Tappin (1966) test has shown itself to offer some great advantages: if the quest is for a fracture toughness test for an unknown tissue it offers reliability, it is perhaps more forgiving to handling errors, it also suffers less of the influence of strain rate effects and uses relatively simple instrumentation. It is also able to demonstrate the remarkable toughness of antler bone which other more commonly used fracture toughness methods cannot do.
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Affiliation(s)
- J D Currey
- Department of Biology, University of York, York YO10 5YW, UK
| | - K Brear
- Department of Biology, University of York, York YO10 5YW, UK
| | - P Zioupos
- Musculoskeletal & Medicolegal Research group, Cranfield Forensic Institute, Cranfield University, Shrivenham SN6 8LA, UK.
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Rosa de Lacerda L, Bossardi M, Silveira Mitterhofer WJ, Galbiatti de Carvalho F, Carlo HL, Piva E, Münchow EA. New generation bulk-fill resin composites: Effects on mechanical strength and fracture reliability. J Mech Behav Biomed Mater 2019; 96:214-218. [PMID: 31055211 DOI: 10.1016/j.jmbbm.2019.04.046] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [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: 03/04/2019] [Revised: 04/18/2019] [Accepted: 04/23/2019] [Indexed: 10/26/2022]
Abstract
PURPOSE To investigate the mechanical performance and fracture reliability of new generation, bulk-fill resin composites of different viscosities. METHODS Forty sound maxillary premolars were prepared into Class I cavities comprised of 5 mm width × 5 mm length × 5 mm thickness. The teeth were randomly allocated into four groups (n = 10) according to the restorative material: Negative control - without restoration; Positive control - conventional resin composite (Opallis; FGM) was applied using increments of up to 2.0 mm-thick; Bulk-Regular - bulk-fill resin composite of regular viscosity (Opus Bulk Fill; FGM) was applied using a single increment of 5 mm-thick; and Bulk-Flow - a low-viscosity bulk-fill resin composite (Opus Bulk Fill Flow; FGM) was applied as the first increment with ∼3.5 mm-thick, followed by two final increments of Opallis (∼1.5 mm-thick). The teeth were stored at 37 °C, for 24 h, and submitted to a mechanical testing machine (DL500; EMIC) under a compressive loading. Work of fracture (Wf) was also obtained. All data were analyzed using ANOVA and Tukey (α = 5%). Reliability of restorations and probability of failure were analyzed by Weibull analysis. RESULTS The non-restored teeth showed the weakest behavior of the study. All the restored groups demonstrated similar mechanical properties to each other (p ≥ 0.242). The positive and negative controls failed exclusively within the cohesiveness of enamel/dentin, whereas the bulk-fill-based restorations showed a mixture of cohesive and mixed failures. The restored groups showed an overall similar reliability, although the Bulk-Regular group demonstrated greater characteristic strength than the positive control. CONCLUSION The novel bulk-fill resin composites of low and regular viscosities show promising application in the restoration of Class I cavities in premolars, demonstrating similar mechanical performance and reliability as compared with restorations prepared using conventional resin composites. From the bulk-fill materials, the version with regular viscosity presented the greatest compliant behavior of the study.
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Affiliation(s)
- Luciano Rosa de Lacerda
- Department of Dentistry, Health Science Institute, Federal University of Juiz de Fora, Governador Valadares, Brazil
| | - Mayara Bossardi
- BioMat Group, Materials Applied to Biosystems, Federal University of Juiz de Fora, Governador Valadares, Brazil
| | | | - Fabíola Galbiatti de Carvalho
- Department of Dentistry, Health Science Institute, Federal University of Juiz de Fora, Governador Valadares, Brazil; BioMat Group, Materials Applied to Biosystems, Federal University of Juiz de Fora, Governador Valadares, Brazil; Graduate Program in Dental Clinic, Federal University of Juiz de Fora, Juiz de Fora, Brazil
| | - Hugo Lemes Carlo
- Department of Dentistry, Health Science Institute, Federal University of Juiz de Fora, Governador Valadares, Brazil; BioMat Group, Materials Applied to Biosystems, Federal University of Juiz de Fora, Governador Valadares, Brazil; Graduate Program in Dental Clinic, Federal University of Juiz de Fora, Juiz de Fora, Brazil
| | - Evandro Piva
- Graduate Program in Dentistry, Federal University of Pelotas, Pelotas, Brazil
| | - Eliseu Aldrighi Münchow
- Department of Dentistry, Health Science Institute, Federal University of Juiz de Fora, Governador Valadares, Brazil; BioMat Group, Materials Applied to Biosystems, Federal University of Juiz de Fora, Governador Valadares, Brazil; Graduate Program in Dental Clinic, Federal University of Juiz de Fora, Juiz de Fora, Brazil.
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Xiao W, Zaeem MA, Li G, Bal BS, Rahaman MN. Tough and strong porous bioactive glass-PLA composites for structural bone repair. J Mater Sci 2017; 52:9039-9054. [PMID: 28943655 PMCID: PMC5606147 DOI: 10.1007/s10853-017-0777-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Accepted: 01/09/2017] [Indexed: 06/07/2023]
Abstract
Bioactive glass scaffolds have been used to heal small contained bone defects but their application to repairing structural bone is limited by concerns about their mechanical reliability. In the present study, the addition of an adherent polymer layer to the external surface of strong porous bioactive glass (13-93) scaffolds was investigated to improve their toughness. Finite element modeling (FEM) of the flexural mechanical response of beams composed of a porous glass and an adherent polymer layer predicted a reduction in the tensile stress in the glass with increasing thickness and elastic modulus of the polymer layer. Mechanical testing of composites with structures similar to the models, formed from 13-93 glass and polylactic acid (PLA), showed trends predicted by the FEM simulations but the observed effects were considerably more dramatic. A PLA layer of thickness -400 µm, equal to -12.5% of the scaffold thickness, increased the load-bearing capacity of the scaffold in four-point bending by ~50%. The work of fracture increased by more than 10,000%, resulting in a non-brittle mechanical response. These bioactive glass-PLA composites, combining bioactivity, high strength, high work of fracture and an internal architecture shown to be conducive to bone infiltration, could provide optimal implants for healing structural bone defects.
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Affiliation(s)
- Wei Xiao
- Department of Materials Science and Engineering, Missouri
University of Science and Engineering, Rolla, Missouri 65409, USA
| | - Mohsen Asle Zaeem
- Department of Materials Science and Engineering, Missouri
University of Science and Engineering, Rolla, Missouri 65409, USA
| | - Guangda Li
- Department of Materials Science and Engineering, Missouri
University of Science and Engineering, Rolla, Missouri 65409, USA
- Department of Medical Technology and Engineering, Henan
University of Science and Technology, Luoyang, China, 471023
| | - B. Sonny Bal
- Department of Orthopaedic Surgery, University of Missouri,
Columbia, Missouri 65212, USA
| | - Mohamed N. Rahaman
- Department of Materials Science and Engineering, Missouri
University of Science and Engineering, Rolla, Missouri 65409, USA
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