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Elraggal A, Abdelraheem IM, Watts DC, Roy S, Dommeti VK, Alshabib A, Althaqafi KA, Afifi RR. Biomechanical reinforcement by CAD-CAM materials affects stress distributions of posterior composite bridges: 3D finite element analysis. Dent Mater 2024; 40:869-877. [PMID: 38609774 DOI: 10.1016/j.dental.2024.04.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2024] [Revised: 03/28/2024] [Accepted: 04/02/2024] [Indexed: 04/14/2024]
Abstract
OBJECTIVES This 3D finite element analysis study aimed to investigate the effect of reinforcing CAD-CAM bars on stress distribution in various components of a posterior composite bridge. METHODS A virtual model mimicking the absence of an upper second premolar was created, featuring class II cavity preparations on the proximal surfaces of the adjacent abutment teeth surrounding the edentulous space. Five distinct finite element analysis (FEA) models were generated, each representing a CAD-CAM reinforcing bar material: 3-YTZP (IPS. emax ZirCAD MO; Zr), lithium disilicate (IPS e.max CAD; EX), nano-hybrid resin composite (Grandio Blocs; GB), Fibre-reinforced composite (Trilor; Tri), and polyetheretherketone (PEEK). A veneering resin composite was employed to simulate the replacement of the missing premolar (pontic). In the FEA, an axial force of 600 N and a transverse load of 20 N were applied at the center of the pontic. Subsequently, maximum von Mises (mvM) and maximum principal stresses (σmax) were computed across various components of the generated models. Additionally, shear stresses at the interface between the CAD-CAM bars and the veneering resin composite were determined. RESULTS CAD-CAM materials with high modulus of elasticity, such as Zr and EX, exhibited the highest mvM stresses and shear stresses while transferring the lowest stress to the veneering resin composite in comparison to other materials. Conversely, PEEK demonstrated the lowest mvM stresses but produced the highest stresses within the veneering resin composite. There was a uniform distribution of mvM stresses in the remaining tooth structure among all groups, except for a noticeable elevation in the molar region of Zr and EX groups. SIGNIFICANCE Reinforcing CAD-CAM bar materials with a high modulus of elasticity, such as Zr and EX, may result in debonding failures at the connector sites of posterior composite bridges. Conversely, GB, PEEK, and Tri have the potential to cause fracture failures at the connectors rather than debonding.
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Affiliation(s)
- Alaaeldin Elraggal
- Division of Dentistry, School of Medical Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK; Conservative Dentistry Department, Faculty of Dentistry, Alexandria University, Alexandria, Egypt.
| | - Islam M Abdelraheem
- Conservative Dentistry Department, Faculty of Dentistry, Alexandria University, Alexandria, Egypt
| | - David C Watts
- Division of Dentistry, School of Medical Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK
| | - Sandipan Roy
- Department of Mechanical Engineering, SRM Institute of Science and Technology, Kattankulathur 603203, Tamil Nadu, India
| | - Vamsi Krishna Dommeti
- Department of Mechanical Engineering, SRM Institute of Science and Technology, Kattankulathur 603203, Tamil Nadu, India
| | - Abdulrahman Alshabib
- Restorative Dentistry Department, Faculty of Dentistry, King Saud University, Riyadh, Saudi Arabia
| | - Khaled Abid Althaqafi
- Restorative Dentistry Department, Faculty of Dentistry, College of Dental Medicine, University of Umm Al Qura, Makkah, Saudi Arabia
| | - Rania R Afifi
- Conservative Dentistry Department, Faculty of Dentistry, Alexandria University, Alexandria, Egypt
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AboElhassan RG, Watts DC, Alamoush RA, Elraggal A. Biomechanical behavior and Weibull survival of CAD-CAM endocrowns with different marginal designs: A 3D finite element analysis. Dent Mater 2024; 40:227-235. [PMID: 37977990 DOI: 10.1016/j.dental.2023.11.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 11/04/2023] [Accepted: 11/06/2023] [Indexed: 11/19/2023]
Abstract
OBJECTIVES To evaluate and compare the effect of tooth preparation designs and different CADCAM. materials on stress distribution and Weibull survival probability of endocrowns. applied to root canal-treated lower first permanent molar using the 3D finite element. analysis method. METHODS A root canal-treated lower first permanent molar was prepared for endocrowns with a. butt joint or with a ferrule design by placing, circumferentially, a 1-mm wide shoulder. finish line. The prepared molar was scanned for the two designs and modeled on a 3D. Finite element model. Monolithic zirconia (IPS e.max ZirCAD MT, FCZ), lithium. disilicate (IPS e.max CAD, EX), and nano-ceramic resin composite (Lava Ultimate, LU). CAD-CAM materials were used for each preparation to design the virtual endocrown. A. total of six models were built according to the different tooth preparation designs and. endocrown materials. An occlusal load of 600 N and a transverse load of 20 N in. magnitude that simulates the average occlusal load was directed toward the occlusal. surfaces. von Mises and maximum principle values were evaluated Weibull risk-ofrupture. analysis was used to analyze the survival probability of the restorations and. tooth in the different models. RESULTS The highest von Mises were found in the butt joint design for FCZ, EX, and LU (45.3. MPa, 35.2 MPa, and 24.2 MPa, respectively) compared to the ferrule design for the. same materials (42.6 MPa, 31.2 MPa, and 23.6 MPa, respectively). For von Mises. stress distribution in the remaining part of tooth structure (dentin), the highest stresses. were found in LUFerrule which was closely similar to LUButt joint (135.4 MPa and. 134.7 MPa, respectively), followed by EXFerrule and FCZFerrule (132.2 MPa and. 131.7 MPa, respectively), while the lowest stresses were found in EXButt joint and. FCZButt joint (129.0 MPa and 128.4 MPa, respectively). Shear stresses within the. resin cement were the highest in FCZ and EX compared to LU. EX was found to be the. most reliable material with the highest survival probability, while FCZ showed the. lowest survival probability according to the Weibull risk-of-fracture results. SIGNIFICANCE Materials with high elastic modulus transfer more stresses to the endocrown and less. to the remaining tooth structure. Endocrown tooth preparation with ferrule design has. better stress distribution and magnitude compared to the butt joint design.
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Affiliation(s)
- Rewaa G AboElhassan
- Conservative Dentistry Department, Faculty of Dentistry, Alexandria University, Alexandria, Egypt
| | - David C Watts
- Division of Dentistry, School of Medical Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK
| | - Rasha A Alamoush
- Department of Fixed and Removable Prosthodontics, School of Dentistry, the University of Jordan, Amman, Jordan
| | - Alaaeldin Elraggal
- Conservative Dentistry Department, Faculty of Dentistry, Alexandria University, Alexandria, Egypt; Division of Dentistry, School of Medical Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK.
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Gönder HY, Mohammadi R, Harmankaya A, Yüksel İB, Fidancıoğlu YD, Karabekiroğlu S. Teeth Restored with Bulk–Fill Composites and Conventional Resin Composites; Investigation of Stress Distribution and Fracture Lifespan on Enamel, Dentin, and Restorative Materials via Three-Dimensional Finite Element Analysis. Polymers (Basel) 2023; 15:polym15071637. [PMID: 37050251 PMCID: PMC10096709 DOI: 10.3390/polym15071637] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2023] [Revised: 03/21/2023] [Accepted: 03/24/2023] [Indexed: 03/29/2023] Open
Abstract
Objectives: the aim of this study was to examine the stress distribution of enamel, dentin, and restorative materials in sound first molar teeth with restored cavities with conventional resin composites and bulk–fill composites, as well as to determine their fracture lifetimes by using the three-dimensional finite element stress analysis method. Materials and Methods: an extracted sound number 26 tooth was scanned with a dental tomography device and recorded. Images were obtained as dicom files, and these files were transferred to the Mimics 12.00 program. In this program, different masks were created for each tooth tissue, and the density thresholds were adjusted manually to create a three-dimensional image of the tooth, and these were converted to a STL file. The obtained STL files were transferred to the Geomagic Design X program, and some necessary adjustments, such as smoothing, were made, and STP files were created. Cavity preparation and adhesive material layers were created by transferring STP files to the Solidworks program. Finally, a FE model was created in the ABAQUS program, and stress distributions were analyzed. Results: when the bulk–fill composite and conventional resin composite materials were used in the restoration of the cavity, the structures that were exposed to the most stress as a result of occlusal forces on the tooth were enamel, dentin, restorative material, and adhesive material. When the bulk–fill composite material was used in restoration, while the restorative material had the longest fracture life as a result of stresses, the enamel tissue had the shortest fracture life. When the conventional resin composite material was used as the restorative material, it had the longest fracture life, followed by dentin and enamel. Conclusion: when the bulk–fill composite material was used instead of the conventional resin composite material in the cavity, the stress values on enamel, dentin, and adhesive material increased as a result of occlusal forces, while the amount of stress on the restorative material decreased. In the fracture analysis, when the bulk–fill composite material was used instead of the conventional resin composite material, a decrease in the number of cycles required for the fracture of enamel, dentin, and restorative materials was observed as a result of the forces generated in the oral cavity.
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Kumar N, Zafar MS. Weibull statistics for strength evaluation of viscoelastic resin-based dental composites. J Taibah Univ Med Sci 2023; 18:1099-1100. [PMID: 37009397 PMCID: PMC10050765 DOI: 10.1016/j.jtumed.2023.03.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2023] [Accepted: 03/02/2023] [Indexed: 03/17/2023] Open
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Ong J, Yap AU, Abdul Aziz A, Yahya NA. Flexural Properties of Contemporary Bioactive Restorative Materials: Effect of Environmental pH. Oper Dent 2023; 48:90-97. [PMID: 36445974 DOI: 10.2341/21-202-l] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/20/2022] [Indexed: 11/30/2022]
Abstract
This study investigated the effects of environmental pH on the flexural properties of ion-releasing restorative materials (IRMs), including giomer (Beautifil-Bulk Restorative - BB), alkasite (Cention N - CN), bioactive composite (Activa - AB) and resin-modified glass ionomer (Riva Light Cure -RV) restoratives. A bio-inert resin-based composite (Filtek Bulk-fill Posterior - FB) served as the control. Stainless steel molds were used to fabricate 40 beam-shaped specimens (12mm × 2mm × 2mm) for each material. The specimens were finished, measured, and randomly distributed into four groups (n=10) and immersed in aqueous solutions of pH 3.0, pH 5.0, pH 6.8, and pH 10.0 at 37°C for 28 days. Specimens were then subjected to a uniaxial three-point bending flexural test with a load cell of 5 KN and a fixed deformation rate of 0.5 mm/min until fracture occurred. Flexural modulus and strength were statistically analyzed using analysis of variance/Dunnet T3's test (p=0.05). Mean flexural modulus varied from (2.40±0.41 to 9.65±1.21 GPa), while mean flexural strength ranged from (21.56±2.78 to 163.86±13.13 MPa). Significant differences in flexural properties were observed among the various pH values and materials. All materials immersed in artificial saliva (pH 6.8) presented the highest flexural properties, except AB. The flexural strength of AB was significantly better when exposed to acidic environments. FB had better flexural properties than IRMs after exposure to a range of environmental pH values.
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Affiliation(s)
- Jex Ong
- Joshua Ee Xin Ong, BDS, MJDF RCS, MOSc, Centre of Restorative Dentistry Studies, Faculty of Dentistry, MARA University of Technology, Malaysia
| | - A U Yap
- Adrian U-Jin Yap, BDS, MSc, PhD, Grad Dip Psychotherapy, Department of Dentistry, Ng Teng Fong General Hospital, National University Health System, Singapore
| | - A Abdul Aziz
- Azwatee Abdul Aziz, BDS, MClinDent, PhD, Department of Restorative Dentistry, Faculty of Dentistry, University of Malaya, Malaysia
| | - N A Yahya
- *Noor Azlin Yahya, DipTrans, BDS, MDentSci, Department of Restorative Dentistry, Faculty of Dentistry, University of Malaya, Malaysia
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Alrahlah A, Khan R, Vohra F, Alqahtani IM, Alruhaymi AA, Haider S, Al-Odayni AB, Saeed WS, Murthy HCA, Bautista LS. Influence of the Physical Inclusion of ZrO 2/TiO 2 Nanoparticles on Physical, Mechanical, and Morphological Characteristics of PMMA-Based Interim Restorative Material. BIOMED RESEARCH INTERNATIONAL 2022; 2022:1743019. [PMID: 36033557 PMCID: PMC9417768 DOI: 10.1155/2022/1743019] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Accepted: 07/28/2022] [Indexed: 11/18/2022]
Abstract
Polymethyl methacrylate (PMMA) is often used in restorative dentistry for its easy fabrication, aesthetics, and low cost for interim restorations. However, poor mechanical properties to withstand complex masticatory forces are a concern for clinicians. Therefore, this study aimed to modify a commercially available PMMA-based temporary restorative material by adding TiO2 and ZrO2 nanoparticles in different percentages as fillers and to investigate its physio-mechanical properties. Different percentages (0, 0.5, 1.5, and 3.0 wt%) of TiO2 and ZrO2 nanoparticles were mixed with the pristine PMMA resin (powder to liquid ratio: 1 : 1) and homogenized using high-speed mixer. The composites obtained were analyzed for their flexural strength (F.S.), elastic modulus (E.M.), Vickers hardness (H.V.), surface roughness Ra, morphology and water contact angle (WCA). The mean average was determined with standard deviation (SD) to analyze the results, and a basic comparison test was conducted. The results inferred that adding a small amount (0.5 wt%) of TiO2 and ZrO2 nanoparticles (NPs) could significantly enhance the physio-mechanical and morphological characteristics of PMMA interim restorations. EM and surface hardness increased with increasing filler content, with 3.0 wt.% ZrO2 exhibiting the highest EM (3851.28 MPa), followed by 3.0 wt.% TiO2 (3632.34 MPa). The WCA was significantly reduced from 91.32 ± 4.21° (control) to 66.30 ± 4.23° for 3.0 wt.% ZrO2 and 69.88 ± 3.55° for 3.0 wt.% TiO2. Therefore, TiO2 and ZrO2 NPs could potentially be used as fillers to improve the performance of PMMA and similar interim restorations.
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Affiliation(s)
- Ali Alrahlah
- Engineer Abdullah Bugshan Research Chair for Dental and Oral Rehabilitation, College of Dentistry, King Saud University, Riyadh 11545, Saudi Arabia
- Restorative Dental Sciences Department, College of Dentistry, King Saud University, Riyadh 11545, Saudi Arabia
| | - Rawaiz Khan
- Engineer Abdullah Bugshan Research Chair for Dental and Oral Rehabilitation, College of Dentistry, King Saud University, Riyadh 11545, Saudi Arabia
| | - Fahim Vohra
- Engineer Abdullah Bugshan Research Chair for Dental and Oral Rehabilitation, College of Dentistry, King Saud University, Riyadh 11545, Saudi Arabia
- Department of Prosthetic Dental Science, College of Dentistry, King Saud University, Riyadh 11545, Saudi Arabia
| | - Ibrahim M. Alqahtani
- Public Security Medical Services, Security Patrols Medical Center, Riyadh, Saudi Arabia
| | - Adel A. Alruhaymi
- Prince Mohammed bin Naif Medical Center, King Fahad Security College, Riyadh, Saudi Arabia
| | - Sajjad Haider
- Department of Chemical Engineering, College of Engineering, King Saud University, PO Box 800, Riyadh 11421, Saudi Arabia
| | - Abdel-Basit Al-Odayni
- Engineer Abdullah Bugshan Research Chair for Dental and Oral Rehabilitation, College of Dentistry, King Saud University, Riyadh 11545, Saudi Arabia
| | - Waseem Sharaf Saeed
- Engineer Abdullah Bugshan Research Chair for Dental and Oral Rehabilitation, College of Dentistry, King Saud University, Riyadh 11545, Saudi Arabia
| | - H. C. Ananda Murthy
- Department of Applied Chemistry, School of Applied Natural Science, Adama Science and Technology University, P O Box, 1888 Adama, Ethiopia
- Department of Prosthodontics, Saveetha Dental College & Hospital, Saveetha Institute of Medical and technical science (SIMAT), Saveetha University, -600077, Chennai, Tamil Nadu, India
| | - Leonel S. Bautista
- Engineer Abdullah Bugshan Research Chair for Dental and Oral Rehabilitation, College of Dentistry, King Saud University, Riyadh 11545, Saudi Arabia
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Zhao H, Liu S, Wei Y, Yue Y, Gao M, Li Y, Zeng X, Deng X, Kotov NA, Guo L, Jiang L. Multiscale engineered artificial tooth enamel. Science 2022; 375:551-556. [PMID: 35113708 DOI: 10.1126/science.abj3343] [Citation(s) in RCA: 70] [Impact Index Per Article: 35.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Tooth enamel, renowned for its high stiffness, hardness, and viscoelasticity, is an ideal model for designing biomimetic materials, but accurate replication of complex hierarchical organization of high-performance biomaterials in scalable abiological composites is challenging. We engineered an enamel analog with the essential hierarchical structure at multiple scales through assembly of amorphous intergranular phase (AIP)-coated hydroxyapatite nanowires intertwined with polyvinyl alcohol. The nanocomposite simultaneously exhibited high stiffness, hardness, strength, viscoelasticity, and toughness, exceeding the properties of enamel and previously manufactured bulk enamel-inspired materials. The presence of AIP, polymer confinement, and strong interfacial adhesion are all needed for high mechanical performance. This multiscale design is suitable for scalable production of high-performance materials.
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Affiliation(s)
- Hewei Zhao
- School of Chemistry, Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University, Beijing 100191, China
| | - Shaojia Liu
- School of Chemistry, Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University, Beijing 100191, China
| | - Yan Wei
- Department of Geriatric Dentistry, NMPA Key Laboratory for Dental Materials, National Engineering Laboratory for Digital and Material Technology of Stomatology, Beijing Laboratory of Biomedical Materials, Peking University School and Hospital of Stomatology, Beijing 100081, China
| | - Yonghai Yue
- School of Chemistry, Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University, Beijing 100191, China
| | - Mingrui Gao
- School of Chemistry, Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University, Beijing 100191, China
| | - Yangbei Li
- School of Chemistry, Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University, Beijing 100191, China
| | - Xiaolong Zeng
- School of Chemistry, Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University, Beijing 100191, China
| | - Xuliang Deng
- Department of Geriatric Dentistry, NMPA Key Laboratory for Dental Materials, National Engineering Laboratory for Digital and Material Technology of Stomatology, Beijing Laboratory of Biomedical Materials, Peking University School and Hospital of Stomatology, Beijing 100081, China
| | - Nicholas A Kotov
- Department of Chemical Engineering, Department of Materials Science, Biointerface Institute, University of Michigan, Ann Arbor, MI 48109, USA.,Michigan Institute of Translational Nanotechnology (MITRAN), Ypsilanti, MI 48198, USA
| | - Lin Guo
- School of Chemistry, Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University, Beijing 100191, China
| | - Lei Jiang
- School of Chemistry, Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University, Beijing 100191, China.,CAS Key Laboratory of Bio-Inspired Materials and Interfacial Science, CAS Center for Excellence in Nanoscience, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, China
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Thermoanalytical Investigations on the Influence of Storage Time in Water of Resin-Based CAD/CAM Materials. Biomedicines 2021; 9:biomedicines9121779. [PMID: 34944594 PMCID: PMC8698771 DOI: 10.3390/biomedicines9121779] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 11/23/2021] [Accepted: 11/24/2021] [Indexed: 11/16/2022] Open
Abstract
New resin-based composites and resin-infiltrated ceramics are used to fabricate computer-aided design (CAD) and computer-aided manufacturing (CAM)-based restorations, although little information is available on the long-term performance of these materials. The aim of this investigation was to determine the effects of storage time (24 h, 90 days, 180 days) on the thermophysical properties of resin-based CAD/CAM materials. Thermogravimetric Analysis (TGA), differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) were used in the study. TGA provided insight into the composition of the resin-based materials and the influence of internal plasticization and water sorption. Resin-based composites showed different decomposition, heat energy and mechanical behavior, which was influenced by storage time in water. Individual materials such as Grandio bloc showed lower influence of water storage while maintaining good mechanical properties.
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Niem T, Gonschorek S, Wöstmann B. Evaluation of the damping capacity of common CAD/CAM restorative materials. J Mech Behav Biomed Mater 2021; 126:104987. [PMID: 34871956 DOI: 10.1016/j.jmbbm.2021.104987] [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: 09/23/2021] [Revised: 11/15/2021] [Accepted: 11/18/2021] [Indexed: 10/19/2022]
Abstract
OBJECTIVES To evaluate and quantify the damping capacities of common CAD/CAM restorative materials (CRMs) and to assess their energy dissipation abilities by comparing loss tangent and Leeb hardness data. METHODS Leeb hardness (HLD), together with its deduced energy dissipation data (HLDdis), and loss tangent values recorded via dynamic mechanical analysis (DMA) were determined for 4 ceramic, 13 composite, and 2 polymer-based CRMs as well as 1 metal. For Leeb hardness, ten indentations per material were performed on two separate specimens (12.0 × 12.0 × 3.5 mm3) after water storage (24 h; 37.0 ± 1.0 °C). For DMA, ten specimens (16.00 × 4.00 × 1.00 mm3 ± 0.05 mm) per material were investigated in distilled water (37.0 ± 0.5 °C) with a dynamic force of 1 N at 1.5 Hz. Each data set was analyzed using two-way analysis of variance (ANOVA) with material type and material nested in material type as factors. Post-ANOVA contrasts were performed using a Bonferroni adjustment for multiple comparisons (α = 0.05). Correlations between different parameters were tested (Pearson, α = 0.05). RESULTS HLDdis data revealed the significantly highest damping capacity for metal and the lowest values for ceramics with composites and polymers in between. However, for loss tangent, the metal together with lithium disilicate glass-ceramics exhibited the lowest damping effects and polymer materials the highest results with composites likewise in between. A strong dependency of the loss tangent results on the filler content of the investigated CRMs was indicated (r = - 0.822, p < 0.001), while a positive and only moderate correlation between loss tangent and HLDdis was observed (r = 0.565, p < 0.001), which conversely revealed a very strong correlation (r = 0.911, p < 0.001) if the metal was excluded from the calculation. CONCLUSIONS Although HLDdis and loss tangent values both allowed a distinct differentiation of the damping capabilities of various CRMs and the respective material types, HLDdis data appeared to more accurately describe the damping capacity of CRMs as the energy dissipation mechanism of permanent plastic material deformation, that is commonly observed for metals and some composite-based CRMs, is equally captured. This finding could be particularly interesting for the future development of new CRMs with improved mechanical properties as HLDdis data determination in principle is a very efficient and simple technique to entirely specify unknown damping capacities of materials.
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Affiliation(s)
- T Niem
- Department of Prosthodontics, Justus-Liebig University, Schlangenzahl 14, 35392, Giessen, Germany.
| | - S Gonschorek
- Department of Prosthodontics, Justus-Liebig University, Schlangenzahl 14, 35392, Giessen, Germany.
| | - B Wöstmann
- Department of Prosthodontics, Justus-Liebig University, Schlangenzahl 14, 35392, Giessen, Germany.
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Al-Saud LM. Comparative evaluation of Rheological characteristics of Giomers and other Nano-flowable resin composites in vitro. Biomater Investig Dent 2021; 8:170-179. [PMID: 34778794 PMCID: PMC8583922 DOI: 10.1080/26415275.2021.1996239] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Objective The purpose of this research was to determine the viscoelastic properties of a group of commercially available nano-flowable resin composites; and to explore the relation between these properties and the materials’ composition (with/without fluoride), filler size description (nano-filled, nanohybrid and submicron-filled) and filler loading (by volume). Methods Rheological measurements were performed using a rheometer. A Dynamic frequency sweep test was conducted to evaluate the complex viscosity, storage and loss moduli, loss tangent, and complex shear modulus at an angular frequency (ω) of 0.1–100 rad/s. Comparative evaluations of the nano flowable resin composites on rheological properties was performed, and statistically analyzed using one-way ANOVA. Results The results indicated that all the tested materials exhibited shear-thinning flow behaviour. As the shear rate increased, the complex viscosity of the nano-flowable composites decreased. The nanohybrid filled flowable resin composites exhibited the highest complex viscosity, while the nano-filled flowable resin composites exhibited the lowest value. The submicron-filled materials exhibited the lowest complex shear moduli and loss tangent values. Conclusions: The findings from the current study provided comprehensive evaluation of the rheological properties of different nano-flowable composites. The observed differences in rheological properties among the tested materials were independent of their fluoride content or filler size. Furthermore, no relationship was found between the complex viscosity of the tested nano-flowable resin composites and their filler volume.
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Affiliation(s)
- Loulwa M Al-Saud
- Division of Operative Dentistry, Department of Restorative Dental Sciences, College of Dentistry, King Saud University, Riyadh, Saudi Arabia
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Gornig DC, Maletz R, Ottl P, Warkentin M. Influence of artificial aging: mechanical and physicochemical properties of dental composites under static and dynamic compression. Clin Oral Investig 2021; 26:1491-1504. [PMID: 34453210 PMCID: PMC8817055 DOI: 10.1007/s00784-021-04122-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Accepted: 08/01/2021] [Indexed: 11/25/2022]
Abstract
OBJECTIVE The aim of the study was to evaluate the influence of filler content, degradation media and time on the mechanical properties of different dental composites after in vitro aging. MATERIALS AND METHODS Specimens (1 mm3) of three commercially available composites (GrandioSO®, Arabesk Top®, Arabesk Flow®) with respect to their filler content were stored in artificial aging media: artificial saliva, ethanol (60%), lactic acid (pH 5) and citric acid (pH 5). Parameters (Vickers microhardness, compressive strength, elastic modulus, water sorption and solubility) were determined in their initial state (control group, n = 3 for microhardness, n = 5 for the other parameters) and after 14, 30, 90 and 180 days (n = 3 for microhardness, n = 5 for the other parameters for each composite group, time point and media). Specimens were also characterized with dynamic-mechanical-thermal analysis (compression tests, F = ± 7 N; f = 0.5 Hz, 1 Hz and 3.3 Hz; t = 0-170 °C). RESULTS Incorporation of fillers with more than 80 w% leads to significantly better mechanical properties under static and dynamic compression tests and a better water sorption behavior, even after chemical degradation. The influence of degradation media and time is of subordinate importance for chemical degradation. CONCLUSION Although the investigated composites have a similar matrix, they showed different degradation behavior. Since dentine and enamel occur only in small layer thickness, a test specimen geometry with very small dimensions is recommended for direct comparison. Moreover, the use of compression tests to determine the mechanical parameters for the development of structure-compatible and functionally adapted composites makes sense as an additional standard. Clinical relevance Preferential use of highly filled composites for occlusal fillings is recommended.
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Affiliation(s)
- D. C. Gornig
- Dres. Irina & Thorsten Brandt, Orthodontic Practice, Wiesbaden, Germany
| | - R. Maletz
- Department of Material Science and Medical Engineering, Faculty of Mechanical Engineering and Marine Technology, University of Rostock, Rostock, Germany
| | - P. Ottl
- Department of Prosthodontics and Material Science, Faculty of Medicine, University of Rostock, Rostock, Germany
| | - M. Warkentin
- Department of Material Science and Medical Engineering, Faculty of Mechanical Engineering and Marine Technology, University of Rostock, Rostock, Germany
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Effect of resin coating on highly viscous glass ionomer cements: A dynamic analysis. J Mech Behav Biomed Mater 2020; 113:104120. [PMID: 33086137 DOI: 10.1016/j.jmbbm.2020.104120] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2020] [Revised: 09/22/2020] [Accepted: 09/28/2020] [Indexed: 11/21/2022]
Abstract
OBJECTIVES This study determined the effects of self-adhesive resin coatings on viscoelastic properties of highly viscous glass ionomer cements (HVGICs) using dynamic mechanical analysis. MATERIALS AND METHODS The HVGICs evaluated were Zirconomer [ZR] (Shofu), Equia Forte [EQ] (GC) and Riva [RV] (SDI). Sixty specimens (12mm x 2mm x 2mm) of each material were fabricated using customized Teflon molds. After initial set, the specimens were removed from their molds, finished, measured and randomly divided into 3 groups of 20. Half the specimens in each group were left uncoated while the remaining half was covered with the respective manufacturers' resin coating. The specimens were subsequently conditioned in distilled water, artificial saliva or citric acid at 37°C for 7 days. The uncoated and coated specimens (n=10) were then subjected to dynamic mechanical testing in flexure mode at 37°C with a frequency of 0.1 to 10Hz. Storage modulus, loss modulus and loss tangent data were subjected to normality testing and statistical analysis using one-way ANOVA/Scheffe's post-hoc test and Ttest at significance level p<0.05. RESULTS Mean storage modulus ranged from 1.39 ± 0.36 to 10.80 ± 0.86 GPa while mean loss modulus varied from 0.13 ± 0.03 to 0.70 ± 0.14 GPa after conditioning in the different mediums. Values for loss tangent ranged from 39.4 ± 7.75 to 213.2 ± 20.11 (x10 -3 ). Significant differences in visco-elastic properties were observed between mediums and materials. When conditioned in distilled water and artificial saliva,storage modulus was significantly improved when ZR, EQ and RV were uncoated. Significantly higher values were, however, observed with resin coating when the materials were exposed to citric acid. CONCLUSION The visco-elastic properties of HVGICs were influenced by both resin coating and chemical environment.
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Shahramian K, Gasik M, Kangasniemi I, Walboomers XF, Willberg J, Abdulmajeed A, Närhi T. Zirconia implants with improved attachment to the gingival tissue. J Periodontol 2020; 91:1213-1224. [PMID: 31858607 DOI: 10.1002/jper.19-0323] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Revised: 11/03/2019] [Accepted: 11/13/2019] [Indexed: 12/25/2022]
Abstract
BACKGROUND Gingival tissue attachment is known to be important for long-term prognosis of implants. This in vitro study evaluated the gingival attachment to zirconia implants and zirconia implants modified with sol-gel derived TiO2 coatings. METHODS Zirconia endodontic posts (n = 23) were used to function as implants that were inserted into the center of full-thickness porcine gingival explants (n = 31). The tissue/implant specimens were then individually placed at an air/liquid interface on a stainless-steel grid in cell culture wells containing a nutrient solution. The tissue cultures were incubated at 37°C in a 5% CO2 environment and at days 7 and 14, the specimens were harvested and analyzed by dynamic mechanical analysis (DMA) measurements under dynamic loading conditions mimicking natural mastication. Specimens were also analyzed by immunohistochemical staining identifying the laminin (Ln) γ2 chain specific for Ln-332, which is known to be a crucial molecule for the proper attachment of epithelium to tooth/implant surface. RESULTS Tissue attachment to TiO2 -coated zirconia demonstrated higher dynamic modulus of elasticity and higher creep modulus, meaning that the attachment is stronger and more resistant to damage during function over time. Laminin γ2 was identified in the attachment of epithelium to TiO2 -coated zirconia. CONCLUSIONS Both DMA and histological analysis support each other, so the gingival tissue is more strongly attached to sol-gel derived TiO2 -coated zirconia than uncoated zirconia. Immunohistochemical staining showed that TiO2 coating may enhance the synthesis and deposition of Ln-332 in the epithelial attachment to the implant surface.
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Affiliation(s)
- Khalil Shahramian
- Department of Prosthetic Dentistry and Stomatognathic Physiology, Institute of Dentistry, University of Turku, Turku, Finland.,Turku Clinical Biomaterials Center (TCBC), University of Turku, Turku, Finland
| | - Michael Gasik
- School of Chemical Engineering, Aalto University Foundation, AALTO, Espoo, Finland
| | - Ilkka Kangasniemi
- Turku Clinical Biomaterials Center (TCBC), University of Turku, Turku, Finland
| | - X Frank Walboomers
- Biomaterials, Radboud University Nijmegen Medical Center, Nijmegen, Netherlands
| | - Jaana Willberg
- Department of Oral Pathology and Radiology, Institute of Dentistry, University of Turku, Turku, Finland.,Department of Pathology, Turku University Central Hospital, Turku, Finland.,Welfare Division, Oral Health Care, Turku, Finland
| | - Aous Abdulmajeed
- Department of General Practice, School of Dentistry, Virginia Commonwealth University, Richmond, VA, USA
| | - Timo Närhi
- Department of Prosthetic Dentistry and Stomatognathic Physiology, Institute of Dentistry, University of Turku, Turku, Finland.,Turku Clinical Biomaterials Center (TCBC), University of Turku, Turku, Finland.,Welfare Division, Oral Health Care, Turku, Finland
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Yap AU, Eweis AH, Yahya NA. Dynamic Viscoelastic Characterization of Bulk-fill Resin-based Composites and Their Conventional Counterparts. Oper Dent 2020; 45:173-182. [DOI: 10.2341/19-005-l] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
SUMMARYThis study compared the viscoelastic properties of restorative and flowable bulk-fill resin-based composites (RBCs) with their conventional counterparts and evaluated the impact of aqueous solutions on viscoelastic properties. The materials examined included three conventional RBCs (Filtek Z350, Tetric N Ceram, and Beautifil II), three restorative bulk-fill RBCs (Filtek Bulk-Fill Restorative, Tetric N Ceram Bulk-Fill, and Beautifil Bulk-Fill Restorative) in addition to three flowable bulk-fill RBCs (Filtek Bulk-Fill Flowable, Tetric N Flow Bulk-Fill, and Beautifil Bulk-Fill Flowable). Beam-shaped specimens (12×2×2 mm) were fabricated using customized stainless-steel molds, finished, and measured. The specimens were randomly divided into four groups and conditioned in air (control), artificial saliva, 0.02 N citric acid, and 50% ethanol-water solution for seven days at 37°C. They were then subjected to dynamic mechanical analysis (n = 10) in flexure mode at 37°C with a frequency of 0.1 to 10 Hz. Storage modulus, loss modulus, and loss tangent data were subjected to statistical analysis using one-way analysis of variance/Tukey post hoc test at a significance level of α = 0.05. Viscoelastic properties of the RBCs were found to be product and conditioning medium dependent. For most RBCs, exposure to aqueous solutions, particularly an ethanol-water solution, degraded viscoelastic properties. With the exception of Filtek Bulk-Fill Restorative, bulk-fill restorative and flowable RBCs generally had significantly lower storage and loss modulus than their conventional counterparts regardless of conditioning medium. Conventional RBCs are thus favored over their bulk-fill counterparts, particularly for high-stress-bearing areas.
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Affiliation(s)
- AU Yap
- Adrian U Yap, PhD, MSc, BDS, adjunct professor, Grad Dip Psychotherapy, Restorative Dentistry, Faculty of Dentistry, University of Malaya, Kuala Lumpur, Malaysia and Department of Dentistry, Ng Teng Fong General Hospital, Singapore
| | - AH Eweis
- Ahmed H Eweis, MDSc, MFDS RCSEd, BDS, Restorative Dentistry, Faculty of Dentistry, University of Malaya, Kuala Lumpur, Malaysia
| | - NA Yahya
- Noor A Yahya, BDS (Otago), MDentSci (Leeds), DipTrans, Restorative Dentistry, Faculty of Dentistry, University of Malaya, Kuala Lumpur, Malaysia
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Eweis AH, Yap AU, Yahya NA. Comparison of Flexural Properties of Bulk-fill Restorative/Flowable Composites and Their Conventional Counterparts. Oper Dent 2020; 45:41-51. [DOI: 10.2341/18-133-l] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
SUMMARY
The objectives of the study were to compare the flexural modulus and strength of restorative and flowable bulk-fill resin-based composites (RBCs) to their conventional counterparts and to determine the effects of conditioning environment on their flexural properties. The materials evaluated included three conventional RBCs (Filtek Z350, Tetric N Ceram, and Beautifil II), three restorative bulk-fill RBCs (Filtek Bulk-Fill Restorative, Tetric N Ceram Bulk-Fill, and Beautifil Bulk-fill Restorative), as well as three flowable bulk-fill RBCs (Filtek Bulk-Fill Flowable, Tetric N Flow Bulk-Fill, and Beautifil Bulk-Fill Flowable). Specimens were fabricated using customized stainless-steel molds, finished, measured, and randomly divided into four groups. The various RBCs were conditioned in the following mediums (n=10) for seven days at 37°C: air, artificial saliva (SAGF), 0.02 N citric acid, and 50% ethanol-water solution. After conditioning, the specimens were rinsed, blotted dry, measured, and subjected to flexural testing using a universal testing machine. Data were subjected to statistical analysis using analysis of variance and the Tukey test at a significance level of α = 0.05. Significant differences in flexural properties were observed between materials and conditioning mediums. Bulk-fill restorative RBCs exhibited higher flexural modulus than their bulk-fill flowable and conventional counterparts. With the exception of Filtek Bulk-Fill Flowable, bulk-fill flowable RBCs had significantly higher flexural strength than bulk-fill restorative and conventional RBCs. Flexural properties were highest when RBCs were conditioned in air and generally the lowest after exposure to ethanol.
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Affiliation(s)
- AH Eweis
- Ahmed H Eweis, MDSc, MFDS RCSEd, BDS, postgraduate, Department of Restorative Dentistry, Faculty of Dentistry, University of Malaya, Kuala Lumpur, Malaysia
| | - AU Yap
- Adrian U-Jin Yap, PhD, MSc, BDS, Grad Dip Psychotherapy, adjunct professor, Department of Dentistry, Ng Teng Fong General Hospital, National University Health System, Singapore; Department of Restorative Dentistry, Faculty of Dentistry, University of Malaya, Kuala Lumpur, Malaysia; and Faculty of Dentistry, National University of Singapore, Singapore
| | - NA Yahya
- Noor A Yahya, MDentSci, BDS, DipTrans, senior lecturer, Department of Restorative Dentistry, Faculty of Dentistry, University of Malaya, Kuala Lumpur, Malaysia
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Yu P, Xiong Y, Zhao P, Xu Z, Yu H, Arola D, Gao S. On the wear behavior and damage mechanism of bonded interface: Ceramic vs resin composite inlays. J Mech Behav Biomed Mater 2019; 101:103430. [PMID: 31557660 DOI: 10.1016/j.jmbbm.2019.103430] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Revised: 09/09/2019] [Accepted: 09/12/2019] [Indexed: 02/05/2023]
Abstract
Advances in adhesive technologies have increased indications for the use of inlays. Decrease in the bonded interface integrity due to wear has been cited as the main cause of its failure. However, this process of interface degradation and the influence of inlay material on damage mechanism appear to be poorly understood. Thus, we aimed to compare the wear behavior and interface damage between ceramic and resin composite inlays bonded to enamel under sliding contact and use the experimental findings to support recommendation of the appropriate inlay material. Bonded interface specimens involving tooth enamel and either ceramic or resin composite inlays were prepared and subjected to reciprocating wear tests up to 5×104 cycles. The wear track profiles and morphologies were characterized after increments of cyclic sliding contact using white light interferometry and scanning electron microscopy, respectively. Optical microscopy was used to evaluate sub-surface cracks and their propagation within the samples. A finite element analysis was used to analyze the stress distributions of the bonded interfaces. Composite inlays showed higher wear depth than the ceramic in the early stage (N ≤ 5×102 cycles), while no significant difference was found at the later stage. For ceramic inlay a greater portion of the contact load was concentrated in the ceramic structure, which facilitated cracks and chipping of the ceramic inlay, with rather minimal damage in the adjacent interface and enamel. In contrast, for the resin composite inlay there was larger stress concentrated in the adjacent enamel, which caused the development of cracks and their propagation to the inner enamel. The restoration material could contribute to the stress distribution and extent of damage within enamel-inlay bonded interfaces. A tough ceramic appears to be more effective at protecting the residual dental tissue.
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Affiliation(s)
- Ping Yu
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Yuhuan Xiong
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Peng Zhao
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Zhou Xu
- Shanghai Putuo District Eye & Tooth Disease Control and Prevention Hospital, Shanghai, China
| | - Haiyang Yu
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Dwayne Arola
- Department of Materials Science and Engineering, University of Washington, Seattle, WA, USA; Departments of Oral Health Sciences, School of Dentistry, University of Washington, Seattle, WA, USA; Departments of Restorative Dentistry, School of Dentistry, University of Washington, Seattle, WA, USA
| | - Shanshan Gao
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China.
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Yap AU, Eweis AH, Yahya NA. Dynamic and Static Flexural Appraisal of Resin-based Composites: Comparison of the ISO and Mini-flexural Tests. Oper Dent 2019; 43:E223-E231. [PMID: 30183531 DOI: 10.2341/17-224-l] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The objective of this study was to determine the influence of specimen dimension and conditioning medium on the dynamic and static flexural properties of resin-based composites (RBCs). One conventional (Filtek Z350) and two bulk-fill RBCs (Filtek Bulk-fill and Beautifil-Bulk Restorative) were evaluated. Bar-shaped specimens with dimensions 25 × 2 × 2 mm (ISO flexural [IFT]) or 12 × 2 × 2 mm (mini-flexural [MFT]) were fabricated using customized stainless-steel molds, finished, measured, randomly divided into two groups, and conditioned in air or artificial saliva (SAGF) for seven days at 37°C. The specimens (n=10) were then subjected to dynamic and static three-point flexural testing. Data for storage modulus, loss modulus, loss tangent, flexural strength, and modulus were computed and subjected to t-test, analysis of variance/Tukey test, and Pearson correlation at a significance level of α = 0.05. For both IFT and MFT, significant differences in dynamic and static flexural properties were more prevalent between materials after storage in saliva. For both conditioning mediums, the strongest correlation between IFT and MFT was observed for flexural strength. While significant positive correlations were observed for all flexural properties with saliva, no significant correlations were detected for loss tangent and flexural modulus with air. For both IFT and MFT, storage in saliva appeared to be more discriminative than storage in air. As moderate to strong positive relationships exist between IFT and MFT for dynamic and static flexural properties, the mini-flexural test holds promise as a replacement for the ISO 4049 in view of its clinical relevance and greater efficiency.
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GRATTAROLA L, DERCHI G, DIASPRO A, GAMBARO C, SALERNO M. Local viscoelastic response of direct and indirect dental restorative composites measured by AFM. Dent Mater J 2018; 37:365-373. [DOI: 10.4012/dmj.2017-048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
| | | | | | - Carla GAMBARO
- Department of Mechanical Engineering, University of Genova
| | - Marco SALERNO
- Department of Nanophysics, Istituto Italiano di Tecnologia
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Ong J, Yap AU, Hong JY, Eweis AH, Yahya NA. Viscoelastic Properties of Contemporary Bulk-fill Restoratives: A Dynamic-mechanical Analysis. Oper Dent 2018. [PMID: 29533719 DOI: 10.2341/16-365-l] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
This study investigated the viscoelastic properties of contemporary bulk-fill restoratives in distilled water and artificial saliva using dynamic mechanical analysis. The materials evaluated included a conventional composite (Filtek Z350), two bulk-fill composites (Filtek Bulk-fill and Tetric N Ceram), a bulk-fill giomer (Beautifil-Bulk Restorative), and two novel reinforced glass ionomer cements (Zirconomer [ZR] and Equia Forte [EQ]). The glass ionomer materials were also assessed with and without resin coating (Equia Forte Coat). Test specimens 12 × 2 × 2 mm of the various materials were fabricated using customized stainless-steel molds. After light polymerization/initial set, the specimens were removed from the molds, finished, measured, and conditioned in distilled water or artificial saliva at 37°C for seven days. The materials (n=10) were then subjected to dynamic mechanical testing in flexure mode at 37°C and a frequency of 0.1 to 10 Hz. Storage modulus, loss modulus, and loss tangent data were subjected to normality testing and statistical analysis using one-way analysis of variance/Dunnett's test and t-test at a significance level of p < 0.05. Mean storage modulus ranged from 3.16 ± 0.25 to 8.98 ± 0.44 GPa, while mean loss modulus ranged from 0.24 ± 0.03 to 0.65 ± 0.12 GPa for distilled water and artificial saliva. Values for loss tangent ranged from 45.7 ± 7.33 to 134.2 ± 12.36 (10-3). Significant differences in storage/loss modulus and loss tangent were observed between the various bulk-fill restoratives and two conditioning mediums. Storage modulus was significantly improved when EQ and ZR was not coated with resin.
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Eweis AH, Yap AUJ, Yahya NA. Dynamic analysis of bulk-fill composites: Effect of food-simulating liquids. J Mech Behav Biomed Mater 2017; 74:183-188. [PMID: 28605721 DOI: 10.1016/j.jmbbm.2017.06.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Accepted: 06/05/2017] [Indexed: 10/19/2022]
Abstract
This study investigated the effect of food simulating liquids on visco-elastic properties of bulk-fill restoratives using dynamic mechanical analysis. One conventional composite (Filtek Z350 [FZ]), two bulk-fill composites (Filtek Bulk-fill [FB] and Tetric N Ceram [TN]) and a bulk-fill giomer (Beautifil-Bulk Restorative [BB]) were evaluated. Specimens (12 × 2 × 2mm) were fabricated using customized stainless steel molds. The specimens were light-cured, removed from their molds, finished, measured and randomly divided into six groups. The groups (n = 10) were conditioned in the following mediums for 7 days at 37°C: air (control), artificial saliva (SAGF), distilled water, 0.02N citric acid, heptane, 50% ethanol-water solution. Specimens were assessed using dynamic mechanical testing in flexural three-point bending mode and their respective mediums at 37°C and a frequency range of 0.1-10Hz. The distance between the supports were fixed at 10mm and an axial load of 5N was employed. Data for elastic modulus, viscous modulus and loss tangent were subjected to ANOVA/Tukey's tests at significance level p < 0.05. Significant differences in visco-elastic properties were observed between materials and mediums. Apart from bulk-fill giomer, elastic modulus was the highest after conditioning in heptane. No apparent trends were noted for viscous modulus. Generally, loss tangent was the highest after conditioning in ethanol. The effect of food-simulating liquids on the visco-elastic properties of bulk-fill composites was material and medium dependent.
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Affiliation(s)
- Ahmed Hesham Eweis
- Department of Restorative Dentistry, Faculty of Dentistry, University of Malaya, Kuala Lumpur, Malaysia
| | - Adrian U-Jin Yap
- Department of Restorative Dentistry, Faculty of Dentistry, University of Malaya, Kuala Lumpur, Malaysia; Department of Dentistry, Ng Teng Fong General Hospital, National University Health System, Singapore
| | - Noor Azlin Yahya
- Department of Restorative Dentistry, Faculty of Dentistry, University of Malaya, Kuala Lumpur, Malaysia.
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Reinforcement of a PMMA resin for interim fixed prostheses with silica nanoparticles. J Mech Behav Biomed Mater 2017; 69:213-222. [DOI: 10.1016/j.jmbbm.2017.01.013] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Revised: 01/04/2017] [Accepted: 01/08/2017] [Indexed: 11/15/2022]
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Jager S, Balthazard R, Vincent M, Dahoun A, Mortier E. Dynamic thermo-mechanical properties of various flowable resin composites. J Clin Exp Dent 2016; 8:e534-e539. [PMID: 27957266 PMCID: PMC5149087 DOI: 10.4317/jced.53061] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Accepted: 03/09/2016] [Indexed: 12/03/2022] Open
Abstract
Background This study compared the storage modulus (E’), the loss modulus (E’’) and the loss tangent (tan δ) of various flowable resin composites. Material and Methods Grandio Flow (GRF), GrandioSo Heavy Flow (GHF), Filtek Supreme XTE (XTE) and Filtek Bulk Fill (BUL) flowable resins and Clinpro Sealant (CLI) ultra-flowable pit and fissure sealant resin were used. 25 samples were tested using a dynamical mechanical thermal analysis system in bending mode. Measurements were taken within a temperature range of 10 to 55°C. The results were statistically analyzed using mixed-effect and repeated-measure analysis of variance followed by paired multiple comparisons. Results For all the materials, the E’ values decrease with temperature, whereas the tan δ values increase. Irrespective of the temperature, GHF and GRF present E’ and E’’ values significantly higher than all the other materials and CLI presents values significantly lower than all the other materials. Observation of the values for all the materials reveals a linear progression of the tan δ values with temperature. Conclusions A variation in temperature within a physiological range generates modifications in mechanical properties without damaging the material, however. Filler content in volume terms appears to be the crucial parameter in the mechanical behavior of tested materials. Key words:Dynamic mechanical thermal analysis, elastic modulus, filler content, flowable resin composites, loss modulus, loss tangent.
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Affiliation(s)
- Stéphanie Jager
- DDS, research fellow, Département d'Odontologie Pédiatrique, Faculté d'Odontologie, 54000 Nancy, France
| | - Rémy Balthazard
- DDS, PhD, Département d'Odontologie Conservatrice, Faculté d'Odontologie, 54000 Nancy, France
| | - Marin Vincent
- DDS, research fellow, Département d'Odontologie Conservatrice, Faculté d'Odontologie, 54000 Nancy, France
| | - Abdessellam Dahoun
- Professor, Institut Jean Lamour UMR 7198 CNRS, Université de Lorraine, Parc de Saurupt, 54011 Nancy Cedex, France
| | - Eric Mortier
- DDS, PhD, Institut Jean Lamour UMR 7198 CNRS, Université de Lorraine, Parc de Saurupt, 54011 Nancy Cedex, France
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Comparison of flowable bulk-fill and flowable resin-based composites: an in vitro analysis. Clin Oral Investig 2016; 20:2123-2130. [DOI: 10.1007/s00784-015-1700-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Accepted: 12/22/2015] [Indexed: 12/23/2022]
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Sideridou ID, Vouvoudi EC, Adamidou EA. Dynamic mechanical thermal properties of the dental light-cured nanohybrid composite Kalore, GC: Effect of various food/oral simulating liquids. Dent Mater 2015; 31:154-61. [DOI: 10.1016/j.dental.2014.11.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Revised: 08/20/2014] [Accepted: 11/14/2014] [Indexed: 11/16/2022]
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Al-Ahdal K, Silikas N, Watts DC. Rheological properties of resin composites according to variations in composition and temperature. Dent Mater 2014; 30:517-24. [DOI: 10.1016/j.dental.2014.02.005] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2014] [Revised: 02/11/2014] [Accepted: 02/11/2014] [Indexed: 10/25/2022]
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Watts DC, Alnazzawi A. Temperature-dependent polymerization shrinkage stress kinetics of resin-composites. Dent Mater 2014; 30:654-60. [PMID: 24703546 DOI: 10.1016/j.dental.2014.03.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2014] [Accepted: 03/06/2014] [Indexed: 10/25/2022]
Abstract
OBJECTIVES To determine temperature dependence of shrinkage stress kinetics for a set of resin composites formulated with dimethacrylate monomer matrices. METHODS Six representative resin composites with a range of resin matrices were selected. Two of them were considered as low shrinking resin composites: Kalore and Venus Diamond. The shrinkage stress kinetics at 23°C and 37°C were measured continuously using a Bioman instrument for 60min. Stress levels between materials were compared at two intervals: 2min and 60min. Specimen temperatures were controlled by a newly designed heating device. Stress measurements were monitored for 1h, after irradiation for 40s at 550mW/cm(2) (energy density=22J/cm(2)). Three specimens (n=3) were used at each temperature per material. RESULTS Shrinkage stress at 23°C ranged from 2.93MPa to 4.71MPa and from 3.57MPa to 5.42MPa for 2min and 60min after photo-activation, respectively. The lowest stress-rates were recorded for Kalore and Venus Diamond (0.34MPas(-1)), whereas the highest was recorded for Filtek Supreme XTE (0.63MPas(-1)). At 37°C, shrinkage stress ranged from 3.27MPa to 5.35MPa and from 3.36MPa to 5.49MPa for 2min and 60min after photo-activation, respectively. Kalore had the lowest stress-rate (0.44MPas(-1)), whereas Filtek Supreme XTE had the highest (0.85MPas(-1)). Materials exhibited a higher stress at 37°C than 23°C except for Kalore and Venus Diamond. Positive correlations were found between shrinkage stress and stress-rate at 23°C and 37°C (r=0.70 and 0.92, respectively). SIGNIFICANCE Resin-composites polymerized at elevated temperature (37°C) completed stress build up more rapidly than specimens held at 23°C. Two composites exhibited atypical reduced stress magnitudes at the higher temperature.
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Affiliation(s)
- D C Watts
- School of Dentistry and Photon Science Institute, University of Manchester, UK; Institute of Materials Science and Technology, Friedrich-Schiller-University, Jena, Germany.
| | - A Alnazzawi
- School of Dentistry and Photon Science Institute, University of Manchester, UK; School of Dentistry, Taibah University, Medina, Saudi Arabia
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Effect of food/oral-simulating liquids on dynamic mechanical thermal properties of dental nanohybrid light-cured resin composites. Dent Mater 2013; 29:842-50. [DOI: 10.1016/j.dental.2013.04.013] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2012] [Revised: 11/13/2012] [Accepted: 04/25/2013] [Indexed: 11/23/2022]
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28
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Varanda E, Do Prado M, Simão RA, Dias KRHC. Effect of in-office bleaching agents on the surface roughness and morphology of different dental composites: An AFM study. Microsc Res Tech 2013; 76:481-5. [DOI: 10.1002/jemt.22190] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2012] [Revised: 12/02/2012] [Accepted: 01/17/2013] [Indexed: 11/05/2022]
Affiliation(s)
- Eduardo Varanda
- Department of Restorative Dentistry; State University of Rio de Janeiro; Rio de Janeiro, Rio de Janeiro; Brazil
| | - Maíra Do Prado
- Department of Dental Clinic; Division of Endodontics; Federal University of Rio de Janeiro; Rio de Janeiro; Brazil
| | - Renata A. Simão
- Department of Metallurgic and Materials Engineering; Federal University of Rio de Janeiro; Rio de Janeiro; Brazil
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Dogar A, Altintas SC, Kavlak S, Guner A. Determining the influence of fibre post light transmission on polymerization depth and viscoelastic behaviour of dual-cured resin cement. Int Endod J 2012; 45:1135-40. [DOI: 10.1111/j.1365-2591.2012.02085.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2010] [Accepted: 05/19/2012] [Indexed: 11/28/2022]
Affiliation(s)
- A. Dogar
- Department of Prosthodontics; Hacettepe University; Ankara; Turkey
| | - S. C. Altintas
- Department of Prosthodontics; Hacettepe University; Ankara; Turkey
| | - S. Kavlak
- Department of Polymer Chemistry; Hacettepe University; Ankara; Turkey
| | - A. Guner
- Department of Polymer Chemistry; Hacettepe University; Ankara; Turkey
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Dynamic mechanical properties of dental nanofilled light-cured resin composites: Effect of food-simulating liquids. J Mech Behav Biomed Mater 2012; 10:87-96. [PMID: 22520421 DOI: 10.1016/j.jmbbm.2012.02.007] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2012] [Revised: 02/08/2012] [Accepted: 02/09/2012] [Indexed: 11/21/2022]
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Sideridou ID, Karabela MM, Spyroudi CS. Dynamic Mechanical Analysis of a Hybrid and a Nanohybrid Light-Cured Dental Resin Composite. JOURNAL OF BIOMATERIALS SCIENCE-POLYMER EDITION 2012; 20:1797-808. [DOI: 10.1163/156856208x386408] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Affiliation(s)
- Irini D. Sideridou
- a Laboratory of Organic Chemical Technology, Department of Chemistry, Aristotle University of Thessaloniki, Thessaloniki GR-54124, Greece
| | - Maria M. Karabela
- b Laboratory of Organic Chemical Technology, Department of Chemistry, Aristotle University of Thessaloniki, Thessaloniki GR-54124, Greece
| | - Crysa S. Spyroudi
- c Laboratory of Organic Chemical Technology, Department of Chemistry, Aristotle University of Thessaloniki, Thessaloniki GR-54124, Greece
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The mechanical stability of nano-hybrid composites with new methacrylate monomers for matrix compositions. Dent Mater 2012; 28:152-9. [DOI: 10.1016/j.dental.2011.11.007] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2010] [Revised: 08/10/2010] [Accepted: 11/07/2011] [Indexed: 11/20/2022]
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33
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Reis JMSN, Giampaolo ET, Pavarina AC, Machado AL, Erxleben J, Vergani CE. Exothermic behavior, degree of conversion, and viscoelastic properties of experimental and commercially available hard chairside reline resins. J Appl Polym Sci 2011. [DOI: 10.1002/app.34268] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Gonçalves F, Azevedo CL, Ferracane JL, Braga RR. BisGMA/TEGDMA ratio and filler content effects on shrinkage stress. Dent Mater 2011; 27:520-6. [DOI: 10.1016/j.dental.2011.01.007] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2010] [Accepted: 01/18/2011] [Indexed: 10/18/2022]
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PROTOPAPA P, KONTONASAKI E, BIKIARIS D, PARASKEVOPOULOS KM, KOIDIS P. Reinforcement of a PMMA resin for fixed interim prostheses with nanodiamonds. Dent Mater J 2011; 30:222-31. [DOI: 10.4012/dmj.2010-135] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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36
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Initial dynamic viscoelasticity change of composites during light curing. Dent Mater 2010; 26:463-70. [DOI: 10.1016/j.dental.2010.01.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2009] [Accepted: 01/11/2010] [Indexed: 11/17/2022]
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Yamanel K, Caglar A, Gülsahi K, Ozden UA. Effects of different ceramic and composite materials on stress distribution in inlay and onlay cavities: 3-D finite element analysis. Dent Mater J 2010; 28:661-70. [PMID: 20019416 DOI: 10.4012/dmj.28.661] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
To reduce loss of tooth tissue and to improve esthetic results, inlay and onlay restorations are good treatment choices for extensive cavities in posterior teeth. The aim of this paper was to evaluate, by means of three-dimensional finite element analysis, the effects of restorative material and cavity design on stress distribution in the tooth structures and restorative materials. Two different nanofilled composites and two different all-ceramic materials were used in this study. A permanent molar tooth was modeled with enamel and dentin structures. 3-D inlay and onlay cavity designs were created. Von Mises, compressive, and tensile stresses on the restorative materials, core materials, enamel, and dentin were evaluated separately. On the effect of restorative material, results showed that in the case of materials with low elastic moduli, more stress was transferred to the tooth structures. Therefore, compared to the nanofilled composites, the all-ceramic inlay and onlay materials tested transferred less stress to the tooth structures. On the effect of cavity design, the onlay design was more efficacious in protecting the tooth structures than the inlay design.
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Affiliation(s)
- Kivanç Yamanel
- Department of Conservative Dentistry, Faculty of Dentistry, Baskent University, Ankara, Turkey.
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Janus J, Fauxpoint G, Arntz Y, Pelletier H, Etienne O. Surface roughness and morphology of three nanocomposites after two different polishing treatments by a multitechnique approach. Dent Mater 2010; 26:416-25. [PMID: 20097415 DOI: 10.1016/j.dental.2009.09.014] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2009] [Revised: 07/19/2009] [Accepted: 09/10/2009] [Indexed: 11/25/2022]
Abstract
OBJECTIVES The purpose of this study was to assess the surface roughness and morphology of three nanocomposites polished with two different polishing systems. METHODS Specimens made of hybrid composite (Tetric Ceram [TC] as control) and nanocomposites: nanofilled (Filtek Supreme [FS]), nanofilled hybrid (Grandio [Gr]), complex nanofilled hybrid (Synergy D6 [Syn]) were polished with CompoSystem [CS] or Sof-Lex [SL] polishing discs. The average surface roughness (Ra) before and after polishing was measured using optical profilometry. Both AFM and SEM techniques were additionally used to analyze the surface morphology after polishing with the aim of relating the surface morphology and the surface roughness. Statistical analysis was done by ANOVA using a general linear model (alpha=0.05) with an adjustment for multiple comparisons. RESULTS Within the same polishing system, FS exhibited the smoothest surface, followed by Syn, TC and Gr (p<0.0001). Sof-Lex polishing discs produced the smoothest surface compared to CompoSystem (p<0.0001). AFM and SEM observations confirmed that the surface roughness was related to the surface morphology and to the average filler size. SIGNIFICANCE Positive correlation between the average filler size and the surface roughness suggest that using nanoparticles in the formulation does not necessary improve the surface texture. The nanofilled composite FS, which contains only nanofillers, showed the best results when associated to Sof-Lex polishing discs.
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Affiliation(s)
- J Janus
- University of Strasbourg, France
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Beun S, Bailly C, Dabin A, Vreven J, Devaux J, Leloup G. Rheological properties of experimental Bis-GMA/TEGDMA flowable resin composites with various macrofiller/microfiller ratio. Dent Mater 2009; 25:198-205. [DOI: 10.1016/j.dental.2008.06.001] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2007] [Revised: 05/26/2008] [Accepted: 06/04/2008] [Indexed: 11/25/2022]
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Almeida CCD, Mothé CG. Avaliação de compósitos odontológicos por análise térmica e microscopia eletrônica de varredura. POLIMEROS 2009. [DOI: 10.1590/s0104-14282009000100018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
O objetivo deste trabalho é caracterizar compósitos odontológicos fotossensíveis por análise térmica (TG, DTG e DTA) e Microscopia Eletrônica de Varredura (SEM). Dentre as marcas comerciais analisadas, quatro marcas são de uso indireto, -Resilab (Wilcos/Brasil), Epricord (Kuraray/Japão), Signum (Heraeus Kulzer/Alemanha) e Sinfony (3M/USA); e foram comparadas com duas marcas de compósitos de uso direto, 4Seasons (Ivoclar Vivadent/Liechtenstein) e Esthet X (Dentsply/USA). Os compósitos de uso direto foram curados por 20 segundos, enquanto que os indiretos foram curados por 180 segundos em diferentes equipamentos, seguindo as indicações dos fabricantes. A decomposição térmica dos compósitos (curados e não curados) foi estudada na temperatura de 30 a 800 °C em atmosfera de nitrogênio com fluxo de 120 -mL.min-1. As curvas de termogravimetria (TG) mostraram que os compósitos com maior estabilidade térmica foram aqueles com menor porcentagem de resíduo a 800 °C. As micrografias dos compósitos revelaram diferentes tamanhos de partículas de carga. A análise térmica apresentou-se como uma ferramenta interessante com precisão, para avaliar o comportamento térmico de compósitos odontológicos.
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Sideridou ID, Karabela MM, Vouvoudi EC. Dynamic thermomechanical properties and sorption characteristics of two commercial light cured dental resin composites. Dent Mater 2008; 24:737-43. [PMID: 17889316 DOI: 10.1016/j.dental.2007.08.004] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2007] [Accepted: 08/16/2007] [Indexed: 11/25/2022]
Abstract
OBJECTIVES The first objective of this work is the study by DMTA of viscoelastic properties (E', E'', tandelta, Tg) of two current dental resin composites Tetric EvoCeram (nanohybrid) and Heliomolar (microfilled) in dry condition and in water for up to 30 days. The second objective is to determine the sorption characteristics of these composites in water and ethanol/water solution 75vol.%. METHODS For DMTA the bar-shaped specimens divided into five groups of three samples each. The first group consisted of dry samples measured 1h after curing. The second and third group consisted of samples, which had been heated in air at 80+/-1 degrees C for 1 day or had been stored in distilled water at 80+/-1 degrees C for 1 day. The fourth and fifth group consisted of samples, which had been stored in distilled water at 37+/-1 degrees C for periods 1 and 7 days correspondingly. Also specimen discs (15mm in diameter and 1mm in thickness) were immersed in water or a 75vol.% ethanol/water solution at 37+/-1 degrees C. At fixed time intervals they were removed, blotted dry to remove excess liquid, weighted and returned to the liquid. This process continued for 30 days. RESULTS The viscoelastic properties (E', E'', tandelta, Tg) of the two composites treated under different conditions were recorded and compared. Also the mass uptake, diffusion coefficient, solubility and volumetric changes for immersion of composites in water and ethanol/water solution 75vol.% at 37+/-1 degrees C were determined. SIGNIFICANCE Tetric EvoCeram a nanohybrid composite with similar about resin matrix with Heliomolar which is a microfilled showed better dynamic thermomechanical properties and sorption characteristics than Heliomolar.
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Affiliation(s)
- Irini D Sideridou
- Laboratory of Organic Chemical Technology, Department of Chemistry, Aristotle University of Thessaloniki, GR-54124 Thessaloniki, Hellas, Greece.
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Mesquita RV, Geis-Gerstorfer J. Influence of temperature on the visco-elastic properties of direct and indirect dental composite resins. Dent Mater 2007; 24:623-32. [PMID: 17826827 DOI: 10.1016/j.dental.2007.06.025] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2006] [Accepted: 06/06/2007] [Indexed: 11/29/2022]
Abstract
OBJECTIVES The first aim of this study was to determine the visco-elastic properties of two direct (DiamondLite and Grandio) and two indirect (Artglass and Vita Zeta LC) dental composites over a wide range of temperatures, in order to avoid choosing a composite that would undergo sudden changes in its mechanical properties during service. METHODS Within this objective the composites were tested immediately after fabrication or after storage at 37 degrees C, either in air or distilled water for 1 day, 7 or 90 days. During dynamic testing, the elastic modulus (E'), viscous modulus (E'') and loss tangent (tandelta) were determined using a dynamic mechanical analyzer (DMA) over a temperature range from 0 to 200 degrees C, at an approximate masticatory frequency of 1 Hz. RESULTS Based on their high glass transition temperatures (Tg) and on the fact that materials are basically equilibrated at 37 degrees C in the mouth and are not thermal conductors, temperature changes from 37 degrees C are expected to be small and should lead to only modest changes in both moduli. However, composites might improve their initial degree of conversion when exposed to normal mouth temperature and higher temperatures due to the ingestion of hot food and beverages. This event can have positive and negative effects on the restoration, such as greater rigidity and additional micro-leakage, respectively. SIGNIFICANCE According to these results it could be said that monitoring the visco-elastic properties of dental composites under conditions that simulate the oral environment seems to be a useful tool to predict their clinical performance as restorative materials.
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Affiliation(s)
- Renata V Mesquita
- Department of Prosthodontics, Section Medical Materials and Technology, University of Tuebingen, Osianderstr. 2-8, 72076 Tuebingen, Germany.
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Khaled SM, Sui R, Charpentier PA, Rizkalla AS. Synthesis of TiO(2)-PMMA nanocomposite: using methacrylic acid as a coupling agent. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2007; 23:3988-95. [PMID: 17316031 DOI: 10.1021/la062879n] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Inorganic-polymer nanocomposites are of significant interest for emerging materials due to their improved properties and unique combination of properties. Methacrylic acid (MA), a functionalization agent that can chemically link TiO2 nanomaterials (n-TiO2) and polymer matrix, was used to modify the surface of n-TiO2 using a Ti-carboxylic coordination bond. Then, the double bond in MA was copolymerized with methyl methacrylate (MMA) to form a n-TiO2-PMMA nanocomposite. The resulting n-TiO2-PMMA nanocomposite materials were characterized by using thermal analysis, electron microscopy, and elemental analysis. The dynamic mechanical properties (Young's and shear modulus) were measured using an ultrasonic pulse technique. The electron microscopy results showed a good distribution of the nanofillers in the polymer matrix. The glass transition temperature, thermal degradation temperature, and dynamic elastic moduli of the nanocomposites were shown to increase with an increase in the weight percentage of nanofibers in the composite. The resulting nanocomposites exhibited improved elastic properties and have potential application in dental composites and bone cements.
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Affiliation(s)
- S M Khaled
- Department of Chemical and Biochemical Engineering, Faculty of Engineering, University of Western Ontario, London, Ontario, Canada N6A 5B9
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Okuda M, Nikaido T, Maruoka R, Foxton RM, Tagami J. Microtensile Bond Strengths to Cavity Floor Dentin in Indirect Composite Restorations using Resin Coating. J ESTHET RESTOR DENT 2007; 19:38-46; discussion 47-8. [PMID: 17244149 DOI: 10.1111/j.1708-8240.2006.00062.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
PURPOSE The aims of this study were (1) to evaluate the effect of a resin coating on the microtensile bond strengths (mu-TBSs) of indirect composite restorations bonded to dentin with resin cement and (2) to compare the mu-TBSs with that of a directly placed composite. MATERIALS AND METHODS Class I cavities were prepared in extracted human molars. The specimens were divided into five groups: For the indirect restorations, the cavity surfaces of the control group were left uncoated (group 1), while the surfaces of the experimental groups were resin coated with a dentin bonding system, Clearfil Protect Bond (PB; groups 2 and 3), or with a combination of PB and a flowable resin composite, Protect Liner F (PLF; group 4). The cavities were temporized for 1 day. Indirect composite restorations (Estenia) were cemented with a resin cement (Panavia F). Pretreatment with ED Primer II was performed in the groups 1, 3, and 4. For the direct restorations, the cavities were restored with PB and a direct composite (Clearfil AP-X; group 5). After 24 hours of water storage, mu-TBSs were measured at a crosshead speed of 1 mm/min. The data were analyzed with one-way analysis of variance and Sheffe's test (p < 0.05). In addition, fracture modes were determined visually and by scanning electron microscopy. RESULTS A combination of PB and PLF showed significantly higher bond strengths compared with the original bond strength of Panavia F and the single use of PB (p < 0.05). However, the highest bond strengths were obtained when PB was used for direct composite restorations (p < 0.05). CONCLUSION The application of a resin coating consisting of a self-etching primer dentin bonding system and a flowable resin composite significantly improved the mu-TBS of indirect restorations bonded to dentin using resin cement. CLINICAL SIGNIFICANCE A resin coating should be required to improve dentin bonding performance of Panavia F in indirect restorations. However, direct composite restorations still provide higher bond strength compared to indirect restorations.
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Affiliation(s)
- Makoto Okuda
- Department of Restorative Sciences, Tokyo Medical and Dental University, Tokyo, Japan.
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