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Tang T, Suputtamongkol K, Harnirattisai C, Neoh SP, Pongprueksa P. Interfacial fracture toughness of different surface treatments on zirconia-reinforced lithium silicate glass-ceramics. Dent Mater J 2023; 42:835-843. [PMID: 37880135 DOI: 10.4012/dmj.2023-124] [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] [Indexed: 10/27/2023]
Abstract
This study investigated the influence of different surface treatments on unfiring or firing zirconia-reinforced lithium silicate (ZLS) glass-ceramics. Celtra Duo and IPS e.max CAD blocks were cut and process following manufacturer protocols. The specimen surface was treated with seven different protocols. Two ceramic blocks with the same surface treatment were bonded with luting agent and prepared for mini-interfacial fracture toughness tests (mini-iFT). The specimens were tested after 1-week storage. The data was statistically analyzed using two-way ANOVA and Dunnett's T3 comparison (α=0.05). The highest mini-iFT of both Celtra Duo unfired and fired was shown in the HF+S group, which was not significantly different from HF+S+UA. For IPS e.max CAD, the mini-iFT was higher in the groups treated with hydrofluoric acid. Additional adhesive after silane application did not significantly improve bonding effectiveness. Therefore, surface treatment with hydrofluoric acid and silane is recommended for both unfiring and firing ZLS glass ceramics.
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Affiliation(s)
- Tianyu Tang
- Dental Biomaterials Science (International Programme), Faculty of Dentistry, Mahidol University
- School and Hospital of Stomatology, Kunming Medical University
| | | | | | - Siew Peng Neoh
- Department of Orthodontics, Faculty of Dentistry, Mahidol University
| | - Pong Pongprueksa
- Department of Operative Dentistry and Endodontics, Faculty of Dentistry, Mahidol University
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Saratti CM, Scotti N, Comba A, Bijelic-Donova J, Suchy T, Abdelaziz M, Leprince JG, Rocca GT. Exploring the influence of placing bi-directional E-glass fibers as protective layer under a CAD-CAM resin composite on the fracture pattern. Dent Mater 2023; 39:986-993. [PMID: 37734973 DOI: 10.1016/j.dental.2023.09.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 08/17/2023] [Accepted: 09/15/2023] [Indexed: 09/23/2023]
Abstract
OBJECTIVES To investigate the influence of the presence and position of bidirectional E-glass fibers under a CAD-CAM resin composite on the fracture pattern evaluated both after quasi-static mechanical loading and after fatigue. METHODS Rectangular specimens (10 mm-long, 5 mm-large and 4.2 mm-thick) were prepared and divided into four groups (n = 30/group). The control group (C-Group) consisted of a 4.2 mm-thick layer of monolithic CAD/CAM resin composite resin (Cerasmart, GC). In the 3 other groups including the placement of a fiber layer (F-Groups), the CAD/CAM resin composite layer was reduced to 3-, 2- and 1-mm thickness (F3-, F2- and F1-Groups, respectively). Two bonded layers of bidirectional E-glass FRC (Dentapreg, ADM A.S.) were bonded underneath and a light-curable resin composite base (Gaenial Posterior, GC) was then added to reach a total thickness of 4.2 mm for all samples. In each group, half of the specimens (n = 15) were submitted to quasi-static mechanical loading to failure in a universal testing machine. The other half (n = 15) was subjected to cyclic isometric stepwise loading until failure or completion of 105000 cycles (5000 cycles at 500 N, followed by five stages of 20000 cycles at 750 N, 1000 N, 1250 N, 1500 N, and 1750 N). The data were analyzed by Weibull statistics for quasi-static loading, and by the Kaplan-Meier product limit estimation procedure after fatigue. All fractured specimens were studied using light and electron microscopy techniques, and the types of fracture were determined. RESULTS For quasi-static mechanical loading, significant differences were observed for Weibull modulus and characteristic strength between groups, with values ranging from 10.8 to 22.4 for the former and from 2336.6 to 2974.7 for the latter. Also, survival after stepwise fatigue revealed statistically significant differences between groups (p < 0.05), the lowest values of cycles before failure being observed for F1-Group - Median = 61223 (50415; 65446) - as compared to the other groups - C-Group: Median = 89005 (86189; 98195); F3-Group: Median = 85198 (77279; 87860); F2-Group: Median = 89306 (87454; 97024). Both in quasi-static loading and after fatigue, the observation of fracture modes revealed major differences. While all fractures were vertical (split) in C-Group, the majority of the specimens in F-Groups presented some degree of horizontal deflection of the crack. In all deviated fractures, fractographic analysis confirmed a toughening effect of the fiber layer. SIGNIFICANCE The present in vitro work tends to show that the fracture pattern of CAD-CAM resin composites is favorably affected by the presence and position of an underlying bidirectional E-glass fiber layer. The placement of E-glass fibers under a CAD-CAM resin composite may therefore represent an interesting strategy to reduce the risk of catastrophic restoration failure, which could be integrated in the development of the new generation of indirect materials, possibly in 3D-printing approaches.
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Affiliation(s)
- C M Saratti
- Division of Cariology and Endodontology, School of Dentistry, University of Geneva, Geneva, Switzerland.
| | - N Scotti
- Department of Surgical Sciences, Dental School, University of Turin, Turin, Italy
| | - A Comba
- Department of Surgical Sciences, Dental School, University of Turin, Turin, Italy
| | - J Bijelic-Donova
- Department of Prosthetic Dentistry and Stomatognathic Physiology, Institute of Dentistry, University of Turku, Lemminkäisenkatu 2, Turku, Finland
| | - T Suchy
- Department of Composites and Carbon Materials, Institute of Rock Structure and Mechanics, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - M Abdelaziz
- Division of Cariology and Endodontology, School of Dentistry, University of Geneva, Geneva, Switzerland
| | - J G Leprince
- Division of Cariology and Endodontology, School of Dentistry, University of Geneva, Geneva, Switzerland
| | - G T Rocca
- Division of Cariology and Endodontology, School of Dentistry, University of Geneva, Geneva, Switzerland
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Lubauer J, Schuenemann FH, Belli R, Lohbauer U. Speed-sintering and the mechanical properties of 3-5 mol% Y 2O 3-stabilized zirconias. Odontology 2023; 111:883-890. [PMID: 36859729 PMCID: PMC10492746 DOI: 10.1007/s10266-023-00796-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Accepted: 02/15/2023] [Indexed: 03/03/2023]
Abstract
Ever faster workflows for the fabrication of all-ceramic restorations are of high economic interest. For that purpose, sintering protocols have been optimized for use in modern sintering furnaces, the so-called speed-sintering. However, conventional furnaces are still the most widely used equipment to sinter zirconia restorations. In this in-vitro study, we evaluated the feasibility of a speed-sintering protocol using a conventional sintering furnace to sinter different dental zirconias (stabilized with 3 mol% up to 5.4 mol% Y2O3) in comparison to a conventional sintering program. The properties evaluated were Young's modulus, Poisson's ratio, density, biaxial flexural strength, and fracture toughness. We show here that despite differences being dependent on material, the physical and mechanical properties of speed-sintered zirconia are comparable to those obtained by the conventional sintering.
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Affiliation(s)
- Julia Lubauer
- Zahnklinik 1-Zahnerhaltung und Parodontologie, Forschungslabor für dentale Biomaterialien, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Glueckstraße 11, 91054, Erlangen, Germany
| | - Fernanda Haverroth Schuenemann
- Zahnklinik 1-Zahnerhaltung und Parodontologie, Forschungslabor für dentale Biomaterialien, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Glueckstraße 11, 91054, Erlangen, Germany
| | - Renan Belli
- Zahnklinik 1-Zahnerhaltung und Parodontologie, Forschungslabor für dentale Biomaterialien, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Glueckstraße 11, 91054, Erlangen, Germany.
| | - Ulrich Lohbauer
- Zahnklinik 1-Zahnerhaltung und Parodontologie, Forschungslabor für dentale Biomaterialien, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Glueckstraße 11, 91054, Erlangen, Germany
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Alqahtani NM, Chaturvedi S, Tomar SS, Kumari L, Gill S, Nayan K, Shariff M, Bhagat TV, Addas MK, Chaturvedi M. Fracture toughness of 3D printed denture teeth. Technol Health Care 2023; 31:247-258. [PMID: 36031920 DOI: 10.3233/thc-220288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
BACKGROUND Advances in digital dentistry lead to use of three-dimensional (3D) printed resin denture teeth. Fracture toughness of these teeth must be assessed. OBJECTIVE This study aimed to compare the chipping and indirect tensile fracture resistance of denture teeth fabricated by 3D printing technique with traditionally fabricated resin denture teeth. METHOD Four groups (Gr) were made (n= 50/group): Gr-1 3D printed denture teeth (denture teeth; Formlabs Inc., Somerville, MA, USA), Gr-2 SR-Orthosit-PE (Ivoclar Vivadent AG), Gr-3 Portrait IPN (Dentsply Sirona), Gr-4 Pala Premium 8 (Heraeus Kulzer GmbH). Stereolithography 3D printing was used to create the methacrylate-based photopolymerized resin teeth models and remaining group teeth were collected commercially. A 1 mm/min chipping and indirect tensile fracture speed tests were carried out till fracture occurred. The data so obtained were statistically analysed using one-way analysis of variance with Tukey's honestly significant difference multiple comparisons test (p< 0.05). At the end of the test, the fractured areas of the specimens were evaluated by the chief researcher to assess the fracture pattern of the teeth. RESULTS The indirect tensile fracture values of the 3D printed teeth were more than that of Pala Premium-8 and SR-Orthosit-PE but it was lower than that of Portrait IPN teeth. In chipping test, buccal chipping of the loaded cusp was seen in 3D printed resin without distortion and in indirect tensile test in 3D printed resin teeth, line of fracture emerges near the loading point propagates from the inner incline of both cusps and extends cervically, unlike in other groups where first deformation occurs then fracture. CONCLUSION Prosthetic teeth fabricated by the 3D printing technique using printable resin material provide adequate fracture resistance as denture teeth.
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Affiliation(s)
- Nasser M Alqahtani
- Department of Prosthetic Dentistry, College of Dentistry, King Khalid University, Abha, Saudi Arabia
| | - Saurabh Chaturvedi
- Department of Prosthetic Dentistry, College of Dentistry, King Khalid University, Abha, Saudi Arabia
| | - Shobhit Singh Tomar
- Dentistry Department, Bundelkhand Medical College, Sagar, Madhya Pradesh, India
| | - Lalima Kumari
- Department of Orthodontics and Dentofacial Orthopaedics, Patna Dental College and Hospital, Patna, India
| | - Shruti Gill
- Department of Prosthodontics, Terna Dental College, Nerul, Navi Mumbai, India
| | - Kamal Nayan
- Department of Prosthodontics and Crown and Bridge, Mithila Minority Dental College and Hospital, Laheriasarai, Darbhanga, Bihar, India
| | - Mansoor Shariff
- Department of Prosthetic Dentistry, College of Dentistry, King Khalid University, Abha, Saudi Arabia
| | - Tushar V Bhagat
- College of Dentistry, Prince Sattam bin Abdulaziz University, AlKharj, Saudi Arabia
| | - Mohammed Khalid Addas
- Department of Prosthetic Dentistry, College of Dentistry, King Khalid University, Abha, Saudi Arabia
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Daabash R, Alshabib A, Alqahtani MQ, Price RB, Silikas N, Alshaafi MM. Ion releasing direct restorative materials: Key mechanical properties and wear. Dent Mater 2022; 38:1866-1877. [DOI: 10.1016/j.dental.2022.09.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 09/18/2022] [Accepted: 09/22/2022] [Indexed: 11/15/2022]
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Wu Y, Liu J, Yang Y, Tu S, Liu Z, Wang Y, Peng C, Liu G, Jin Y. Special architecture and anti-wear strategies for giant panda tooth enamel: Based on wear simulation findings. Front Vet Sci 2022; 9:985733. [PMID: 36187810 PMCID: PMC9516319 DOI: 10.3389/fvets.2022.985733] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2022] [Accepted: 08/10/2022] [Indexed: 11/13/2022] Open
Abstract
Giant pandas are the flagship species in world conservation. Due to bamboo being the primary food source for giant pandas, dental wear is common owing to the extreme toughness of the bamboo fiber. Even though research on tooth enamel wear in humans and domestic animals is well-established, research on tooth enamel wear in giant pandas is scarce. The purpose of this study is to evaluate tooth enamel wear resistance in giant pandas to provide a basis for a better understanding of their evolutionary process. From microscopic and macroscopic perspectives, the abrasion resistance of dental enamel in giant pandas is compared with that of herbivorous cattle and carnivorous dogs in this study. This involves the use of micro-scratch and frictional wear tests. The results show that the boundary between the enamel prism and the enamel prism stroma is well-defined in panda and canine teeth, while bovine tooth enamel appears denser. Under constant load, the tribological properties of giant panda enamel are similar to those of canines and significantly different from those of bovines. Test results show that the depth of micro scratches in giant panda and canine enamel was greater than in cattle, with greater elastic recovery occurring in dogs. Scratch morphology indicates that the enamel substantive damage critical value is greater in pandas than in both dogs and cattle. The analysis suggests that giant panda enamel consists of a neatly arranged special structure that may disperse extrusion stress and absorb impact energy through a series of inelastic deformation mechanisms to cope with the wear caused by eating bamboo. In this study, the excellent wear resistance of giant panda's tooth enamel is verified by wear tests. A possible theoretical explanation of how the special structure of giant panda tooth enamel may improve its wear resistance is provided. This provides a direction for subsequent theoretical and experimental studies on giant panda tooth enamel and its biomaterials.
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Affiliation(s)
- Yuanheng Wu
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, China Agricultural University, Beijing, China
| | - Jinxing Liu
- Tsinghua Laboratory of Brain and Intelligence, Nonhuman Primate Research Center Tsingua University, Beijing, China
| | - Yongqiang Yang
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, China Agricultural University, Beijing, China
| | - Shaotong Tu
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, China Agricultural University, Beijing, China
| | - Zichen Liu
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, China Agricultural University, Beijing, China
| | - Yingyun Wang
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, China Agricultural University, Beijing, China
| | - Chen Peng
- Department of Preventive Veterinary Medicine, College of Veterinary Medicine, China Agricultural University, Beijing, China
| | - Gang Liu
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, China Agricultural University, Beijing, China
- *Correspondence: Gang Liu
| | - Yipeng Jin
- Department of Clinical Veterinary Medicine, College of Veterinary Medicine, China Agricultural University, Beijing, China
- Yipeng Jin
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Sabino SDRF, Cordeiro BGB, Silva LD, Pukasiewicz AG, Zanotto ED, Serbena FC. Microstructural and residual stress effects on toughening of stoichiometric BaO.2SiO2 glass-ceramics. Ann Ital Chir 2022. [DOI: 10.1016/j.jeurceramsoc.2022.05.073] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Begand S, Spintzyk S, Geis-Gerstorfer J, Bourauel C, Keilig L, Lohbauer U, Worpenberg C, Greuling A, Adjiski R, Jandt KD, Lümkemann N, Stawarczyk B, Güllmar A, Kailer A, Oberle N, Stephan M. Fracture toughness of 3Y-TZP ceramic measured by the Chevron-Notch Beam method: A round-robin study. Dent Mater 2022; 38:1128-1139. [PMID: 35618552 DOI: 10.1016/j.dental.2022.05.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Revised: 05/03/2022] [Accepted: 05/03/2022] [Indexed: 11/28/2022]
Abstract
OBJECTIVE This interlaboratory round robin test investigated the robustness of the Chevron-Notch Beam (CNB) test method and the effect of the processing and testing variations on the fracture toughness of a dental 3Y-TZP ceramic. METHODS The round robin test was performed precisely following the procedures recommended in ISO 24370:2005 and applied on a commercial 3Y-TZP ceramic (product information). A total of 335 test specimens with dimensions 3×4 x 45 mm³ was equally distributed among 10 participating laboratories of varying experience in fracture toughness testing. A standard operating procedure was defined with either narrow processing tolerances or alternative (wider) processing tolerances (as proposed in ISO 24370). Fracture toughness data (series 2) was analyzed using one way ANOVA followed by post hoc Tukey HSD test and 95% Confidence Intervals (CI) were computed (p < 0.05). A further, preceding round-robin (series 1) test was conducted with - more possible variations of test conditions regarding CNB notch processing and storage conditions. Those results are summarized in the supplement and discussed with the actual ISO 24370 test. RESULTS Fracture toughness of the 3Y-TZP ceramic material, summarized over all laboratories was measured to KIc = 4.48 ± 0.11 MPam0.5 for the standard processing tolerance and KIc = 4.55 ± 0.31 MPam0.5 for the alternative tolerance. The results revealed a significant influence of cutting offset and notch geometry on KIc when using CNB method. The test medium also has a significant influence on KIc in terms of reduced fracture toughness under the influence of water. With defined testing conditions the number of valid tests and reduced standard deviation increased. In case of strictly following such standard operation procedures, KIc can be determined with high reliability. There is no difference between the involved laboratories, but significant influence of cutting offset on KIC was observed. SIGNIFICANCE The CNB method is suitable method for determination of KIc on fine-grained ceramics such as 3Y-TZP ceramic. By using tighter tolerances for processing and testing, i.e. closely following the ISO 24370 procedure, a highly-precise evaluation of fracture toughness with low data variation is achievable. The information of the storage medium should always be reported along with the data. CNB fracture toughness testing is an alternative method compared to Single-edge V-notch beam (SEVNB), especially for fine-grained ceramics.
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Affiliation(s)
- Sabine Begand
- Fraunhofer Institute for Ceramics Technologies and Systems IKTS, Michael-Faraday-Str. 1, 07629 Hermsdorf, Germany.
| | - Sebastian Spintzyk
- University Hospital Tübingen, Section "Medical Materials Science & Technology", Osianderstr. 2-8, 72076 Tuebingen, Germany
| | - Jürgen Geis-Gerstorfer
- University Hospital Tübingen, Section "Medical Materials Science & Technology", Osianderstr. 2-8, 72076 Tuebingen, Germany
| | - Christoph Bourauel
- University Hospital Bonn, Oral Technology, School of Dentistry, University of Bonn, Welschnonnenstr. 17, 53111 Bonn, Germany
| | - Ludger Keilig
- University Hospital Bonn, Oral Technology, School of Dentistry, University of Bonn, Welschnonnenstr. 17, 53111 Bonn, Germany
| | - Ulrich Lohbauer
- University of Erlangen-Nuremberg, Dental Clinic 1 - Operative Dentistry and Periodontology, Glueckstrasse 11, 91054 Erlangen, Germany
| | - Christin Worpenberg
- Hannover Medical School, Clinic for Dental Prosthetics, Carl-Neuberg-Straße 1, 30625 Hannover, Germany
| | - Andreas Greuling
- Hannover Medical School, Clinic for Dental Prosthetics, Carl-Neuberg-Straße 1, 30625 Hannover, Germany
| | - Ranko Adjiski
- Otto Schott Institute of Materials Research, Friedrich Schiller University Jena, Löbdergraben 32, 07743 Jena, Germany
| | - Klaus D Jandt
- Otto Schott Institute of Materials Research, Friedrich Schiller University Jena, Löbdergraben 32, 07743 Jena, Germany
| | - Nina Lümkemann
- Department of Prosthetic Dentistry, University Hospital, Dental School, Ludwig-Maximilians-University Munich, Goethestraße 70, 80336 Munich, Germany
| | - Bogna Stawarczyk
- Department of Prosthetic Dentistry, University Hospital, Dental School, Ludwig-Maximilians-University Munich, Goethestraße 70, 80336 Munich, Germany
| | - André Güllmar
- University Hospital Jena, Polyclinic for Conservative Dentistry, An der Alten Post, 407743 Jena, Germany
| | - Andreas Kailer
- Fraunhofer IWM, Freiburg, Wöhlerstraße 11, 79108 Freiburg im Breisgau, Germany
| | - Natalie Oberle
- Fraunhofer IWM, Freiburg, Wöhlerstraße 11, 79108 Freiburg im Breisgau, Germany
| | - Marc Stephan
- Materials Competence Center bei Institut Straumann AG, Peter-Merian-Weg 12, CH-4002 Basel, Switzerland
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A split-Chevron-Notched-Beam sandwich specimen for fracture toughness testing of bonded interfaces. J Mech Behav Biomed Mater 2022; 131:105236. [DOI: 10.1016/j.jmbbm.2022.105236] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Revised: 04/06/2022] [Accepted: 04/10/2022] [Indexed: 11/22/2022]
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Zhao M, Yang D, Fan S, Yao X, Wang J, Zhu M, Zhang Y. 3D-Printed Strong Dental Crown with Multi-Scale Ordered Architecture, High-Precision, and Bioactivity. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2104001. [PMID: 34936228 PMCID: PMC8844577 DOI: 10.1002/advs.202104001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Revised: 11/17/2021] [Indexed: 05/02/2023]
Abstract
Mimicking the multi-scale highly ordered hydroxyapatite (HAp) nanocrystal structure of the natural tooth enamel remains a great challenge. Herein, a bottom-up step-by-step strategy is developed using extrusion-based 3D printing technology to achieve a high-precision dental crown with multi-scale highly ordered HAp structure. In this study, hybrid resin-based composites (RBCs) with "supergravity +" HAp nanorods can be printed smoothly via direct ink writing (DIW) 3D printing, induced by shear force through a custom-built nozzle with a gradually shrinking channel. The theoretical simulation results of finite element method are consistent with the experimental results. The HAp nanorods are first highly oriented along a programmable printing direction in a single printed fiber, then arranged in a layer by adjusting the printing path, and finally 3D printed into a highly ordered and complex crown structure. The printed samples with criss-crossed layers by interrupting crack propagation exhibit a flexural strength of 134.1 ± 3.9 MPa and a compressive strength of 361.6 ± 8.9 MPa, which are superior to the corresponding values of traditional molding counterparts. The HAp-monodispersed RBCs are successfully used to print strong and bioactive dental crowns with a printing accuracy of 95%. This new approach can help provide customized components for the clinical restoration of teeth.
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Affiliation(s)
- Menglu Zhao
- State Key Laboratory for Modification of Chemical Fibers and Polymer MaterialsShanghai Belt and Road Joint Laboratory of Advanced Fiber and Low‐dimension MaterialsCollege of Materials Science and EngineeringDonghua UniversityShanghai201620P. R. China
| | - Danlei Yang
- State Key Laboratory of Organic‐Inorganic CompositesBeijing University of Chemical TechnologyBeijing100029P. R. China
| | - Suna Fan
- State Key Laboratory for Modification of Chemical Fibers and Polymer MaterialsShanghai Belt and Road Joint Laboratory of Advanced Fiber and Low‐dimension MaterialsCollege of Materials Science and EngineeringDonghua UniversityShanghai201620P. R. China
| | - Xiang Yao
- State Key Laboratory for Modification of Chemical Fibers and Polymer MaterialsShanghai Belt and Road Joint Laboratory of Advanced Fiber and Low‐dimension MaterialsCollege of Materials Science and EngineeringDonghua UniversityShanghai201620P. R. China
| | - Jiexin Wang
- State Key Laboratory of Organic‐Inorganic CompositesBeijing University of Chemical TechnologyBeijing100029P. R. China
| | - Meifang Zhu
- State Key Laboratory for Modification of Chemical Fibers and Polymer MaterialsShanghai Belt and Road Joint Laboratory of Advanced Fiber and Low‐dimension MaterialsCollege of Materials Science and EngineeringDonghua UniversityShanghai201620P. R. China
| | - Yaopeng Zhang
- State Key Laboratory for Modification of Chemical Fibers and Polymer MaterialsShanghai Belt and Road Joint Laboratory of Advanced Fiber and Low‐dimension MaterialsCollege of Materials Science and EngineeringDonghua UniversityShanghai201620P. R. China
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Lubauer J, Belli R, Peterlik H, Hurle K, Lohbauer U. Grasping the Lithium hype: Insights into modern dental Lithium Silicate glass-ceramics. Dent Mater 2021; 38:318-332. [PMID: 34961642 DOI: 10.1016/j.dental.2021.12.013] [Citation(s) in RCA: 45] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Revised: 11/30/2021] [Accepted: 12/08/2021] [Indexed: 11/03/2022]
Abstract
OBJECTIVES Lithium-based glass-ceramics are currently dominating the landscape of dental restorative ceramic materials, with new products taking the market by storm in the last years. Though, the difference among all these new and old products is not readily accessible for the practitioner, who faces the dilemma of reaching a blind choice or trusting manufacturers' marketing brochures. To add confusion, new compositions tend to wear material terminologies inherited from vanguard dental lithium disilicates, disregarding accuracy. Here we aim to characterize such materials for their microstructure, crystalline fraction, glass chemistry and mechanical properties. METHODS Eleven commercial dental lithium-based glass ceramics were evaluated: IPS e.max® CAD, IPS e.max® Press, Celtra® Duo, Suprinity® PC, Initial™ LiSi Press, Initial™ LiSi Block, Amber® Mill, Amber® Press, N!CE®, Obsidian® and CEREC Tessera™. The chemical composition of their base glasses was measured by X-Ray Fluorescence Spectroscopy (XRF) and Inductive Coupled Plasma Optical Emission Spectroscopy (ICP-OES), as well as the composition of their residual glass by subtracting the oxides bound in the crystallized fraction, characterized by X-Ray Diffraction (XRD) and Rietveld refinement, and quantified accurately using the G-factor method (QXRD). The crystallization behavior is revealed by differential scanning calorimetry (DSC) curves. Elastic constants are provided from Resonant Ultrasound Spectroscopy (RUS) and the fracture toughness measured by the Ball-on-Three-Balls method (B3B- K Ic). The microstructure is revealed by field-emission scanning electron microscopy (FE-SEM). RESULTS The base glasses showed a wide range of SiO2 /Li2O ratios, from 1.5 to 3.0, with the degree of depolymerization dropping from ½ to 2/3 of the initial connectivity. Materials contained Li2SiO3+Li3PO4, Li2SiO3+Li3PO4+Li2Si2O5, Li2Si2O5+Li3PO4+ Cristobalite and/or Quartz and Li2Si2O5+Li3 PO4+LiAlSi2O6, in crystallinity degrees from 45 to 80 vol%. Crystalline phases could be traced to their crystallization peaks on the DSC curves. Pressable materials and IPS e.max® CAD were the only material showing micrometric phases, with N!CE® and Initial™ LiSi Block showing solely nanometric crystals, with the rest presenting a mixture of submicrometric and nanometric particles. Fracture toughness from 1.45 to 2.30 MPa√m were measured, with the linear correlation to crystalline fraction breaking down for submicrometric and nanometric crystal phases. SIGNIFICANCE Dental lithium-based silicate glass-ceramics cannot be all put in the same bag, as differences exist in chemical composition, microstructure, crystallinity and mechanical properties. Pressable materials still perform better mechanically than CAM/CAM blocks, which loose resistance to fracture when crystal phases enter the submicrometric and nanometric range.
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Affiliation(s)
- Julia Lubauer
- Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Zahnklinik 1 - Zahnerhaltung und Parodontologie, Forschungslabor für dentale Biomaterialien, Glueckstrasse 11, 91054 Erlangen, Germany
| | - Renan Belli
- Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Zahnklinik 1 - Zahnerhaltung und Parodontologie, Forschungslabor für dentale Biomaterialien, Glueckstrasse 11, 91054 Erlangen, Germany.
| | - Herwig Peterlik
- Faculty of Physics, University of Vienna, Boltzmanngasse 5, A-1090 Vienna, Austria
| | - Katrin Hurle
- Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), GeoZentrum Nordbayern, Mineralogy, Schlossgarten 5a, 91054 Erlangen, Germany
| | - Ulrich Lohbauer
- Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Zahnklinik 1 - Zahnerhaltung und Parodontologie, Forschungslabor für dentale Biomaterialien, Glueckstrasse 11, 91054 Erlangen, Germany
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Relationships between fracture toughness, Y2O3 fraction and phases content in modern dental Yttria-doped zirconias. Ann Ital Chir 2021. [DOI: 10.1016/j.jeurceramsoc.2021.08.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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The effect of dental restoration geometry and material properties on biomechanical behaviour of a treated molar tooth: A 3D finite element analysis. J Mech Behav Biomed Mater 2021; 125:104892. [PMID: 34688146 DOI: 10.1016/j.jmbbm.2021.104892] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 10/08/2021] [Accepted: 10/10/2021] [Indexed: 11/21/2022]
Abstract
OBJECTIVES To test the hypothesis that restoration of class II mesio-occlusal-distal (MOD) cavities can be strengthened through judicious choice of restoration geometry and material properties. METHODS An intact extracted human maxillary molar tooth was digitized, segmented, reconstructed, and four 3D restored tooth models were developed with four different restoration geometries: one straight, one single-curved, and two double-curved. Stress analysis was conducted for representative loading using finite element analysis, and maximum principal stresses were determined at the dentine-enamel and restoration-enamel junctions. A range of restorative material elastic moduli (5-80 GPa) and Poisson's ratios (0.25-0.35) were studied. Vertical loads of 400 N were applied on occlusal points, while the roots of the molar teeth, below the crevices, were supported in all directions. All the materials were modelled as homogeneous, isotropic, and elastic. RESULTS The maximum principal stresses at the restoration-enamel junctions were strongly dependent on the MOD restoration geometries. Peak stresses occurred along the palatal surface of the restoration rather than the opposite buccal surface. Double-curved restorations showed the lowest peak stress at restoration-enamel junctions. Choice of the mechanical properties of restorative material in the range of 5-35 GPa further reduced stress concentrations on the enamel. SIGNIFICANCE Class II MOD restorations may be stronger if designed with double-curved marginal geometries that can reduce stress concentrations. Designs with convex and concave geometries were particularly effective because they reduced stress concentrations dramatically. Results suggest that relatively minor changes to the geometry of a restoration can have a substantial effect on stress at the restoration-enamel junction and motivate future experimental analysis.
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Lubauer J, Hurle K, Cicconi MR, Petschelt A, Peterlik H, Lohbauer U, Belli R. Toughening by revitrification of Li 2SiO 3 crystals in Obsidian® dental glass-ceramic. J Mech Behav Biomed Mater 2021; 124:104739. [PMID: 34488173 DOI: 10.1016/j.jmbbm.2021.104739] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Revised: 07/21/2021] [Accepted: 07/27/2021] [Indexed: 11/26/2022]
Abstract
As a predominantly lithium-metasilicate-containing glass-ceramic, Obsidian® (Glidewell Laboratories, USA) has a peculiar composition and microstructure among other dental lithium silicates, warranting an evaluation of the crystallization process to establish relationships between microstructural evolution and mechanical properties. Blocks of the pre-crystallized material were processed into slices measuring 12 × 12 × 1.5 mm3 and subjected to the mandatory crystallization firing by interruption the heating ramp at temperatures between 700 °C and 820 °C (dwell time between 0 min and 10 min). The crystallization peaks of the base and the pre-crystallized glass were obtained by differential scanning calorimetry (DSC). The coefficient of thermal expansion and the glass transition temperature were derived from differential thermal analysis (DTA). X-ray diffraction (XRD) was performed to quantify and characterize the crystal phase fraction, whose microstructural changes were visualised using FE-SEM. The ball-on-three-balls surface crack in flexure method was used to track the evolution of fracture toughness. The microstructural evolution during crystallization firing was characterized by two regimes of growth: (i) the progressive revitrification (dissolution) of the 5 μm-sized Li2SiO3 polycrystals manifested at the boundaries of nanometric single coherent scattering domains (CSDs); (ii) the non-isothermal period is marked by an Ostwald ripening process characterized by the growth of the single crystalline structures into 0.5 μm polycrystals. The decrease in the crystal fraction of Li2SiO3 crystals from 41 vol.% to 37 vol.% is accompanied by the formation of a small amount of Li3PO4 (6 vol.%), maintaining the total crystal phase fraction mostly constant. The KIc accompanied the reverse trend of crystallinity, departing from 1.63 ± 0.02 MPa√m at the pre-crystallized stage to 1.84 ± 0.06 MPa√m after 10 min at 820 °C in a linear trend. Toughening appeared counter-intuitive in view of the decreasing crystal fraction and size, to rather relate to the relaxation of the residual stresses in the interstitial glass due to the spheroidization of the initially anisotropic, elongated Li2SiO3 crystals into round, nearly equiaxed particles, as let suggest from the disappearance of the extensive microcracking.
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Affiliation(s)
- Julia Lubauer
- Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Zahnklinik 1 - Zahnerhaltung und Parodontologie, Forschungslabor für Dentale Biomaterialien, Glueckstrasse 11, 91054, Erlangen, Germany.
| | - Katrin Hurle
- Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), GeoZentrum Nordbayern, Mineralogy, Schlossgarten 5a, 91054, Erlangen, Germany
| | - Maria Rita Cicconi
- Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Department Werkstoffwissenschaften, Institut für Glas und Keramik, Martenstrasse 5, 91058, Erlangen, Germany
| | - Anselm Petschelt
- Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Zahnklinik 1 - Zahnerhaltung und Parodontologie, Forschungslabor für Dentale Biomaterialien, Glueckstrasse 11, 91054, Erlangen, Germany
| | - Herwig Peterlik
- Faculty of Physics, University of Vienna, Boltzmanngasse 5, A-1090, Vienna, Austria
| | - Ulrich Lohbauer
- Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Zahnklinik 1 - Zahnerhaltung und Parodontologie, Forschungslabor für Dentale Biomaterialien, Glueckstrasse 11, 91054, Erlangen, Germany
| | - Renan Belli
- Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Zahnklinik 1 - Zahnerhaltung und Parodontologie, Forschungslabor für Dentale Biomaterialien, Glueckstrasse 11, 91054, Erlangen, Germany
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15
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Lubauer J, Belli R, Schünemann FH, Matta RE, Wichmann M, Wartzack S, Völkl H, Petschelt A, Lohbauer U. Inner marginal strength of CAD/CAM materials is not affected by machining protocol. Biomater Investig Dent 2021; 8:119-128. [PMID: 34447944 PMCID: PMC8386733 DOI: 10.1080/26415275.2021.1964969] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Purpose Here we aimed to compare two machining strategies regarding the marginal strength of CAD/CAM materials using a hoop-strength test in model sphero-cylindrical dental crowns, coupled with finite element analysis. Materials and Methods Five CAD/CAM materials indicated for single posterior crowns were selected, including a lithium disilicate (IPS e.max® CAD), a lithium (di)silicate (Suprinity® PC), a polymer-infiltrated ceramic scaffold (Enamic®), and two indirect resin composites (Grandio® Blocs and Lava™ Ultimate). A sphero-cylindrical model crown was built on CAD Software onto a geometrical abutment and machined using a Cerec MC XL system according to the two available protocols: rough-fast and fine-slow. Specimens were fractured using a novel hoop-strength test and analyzed using the finite element method to obtain the inner marginal strength. Data were evaluated using Weibull statistics. Results Machining strategy did not affect the marginal strength of any restorative material tested here. Ceramic materials showed a higher density of chippings in the outer margin, but this did not reduce inner marginal strength. IPS e.max® CAD showed the statistically highest marginal strength, and Enamic® and Lava™ Ultimate were the lowest. Grandio® Blocs showed higher performance than Suprinity® PC. Conclusions The rough-fast machining strategy available in Cerec MC XL does not degrade the marginal strength of the evaluated CAD/CAD materials when compared to its fine-fast machining strategy. Depending on the material, resin composites have the potential to perform better than some glass-ceramic materials.
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Affiliation(s)
- Julia Lubauer
- Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Zahnklinik 1 - Zahnerhaltung und Parodontologie, Forschungslabor für dentale Biomaterialien, Erlangen, Germany
| | - Renan Belli
- Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Zahnklinik 1 - Zahnerhaltung und Parodontologie, Forschungslabor für dentale Biomaterialien, Erlangen, Germany
| | - Fernanda H Schünemann
- Post-Graduate Program in Dentistry (PPGO), School of Dentistry, Federal University of Santa Catarina, Florianópolis, Brazil
| | - Ragai E Matta
- Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Zahnklinik 2 - Prothetik, Labor für digitale Zahnmedizin, Erlangen, Germany
| | - Manfred Wichmann
- Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Zahnklinik 2 - Prothetik, Labor für digitale Zahnmedizin, Erlangen, Germany
| | - Sandro Wartzack
- Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Lehrstuhl für Konstruktionstechnik, Erlangen, Germany
| | - Harald Völkl
- Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Lehrstuhl für Konstruktionstechnik, Erlangen, Germany
| | - Anselm Petschelt
- Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Zahnklinik 1 - Zahnerhaltung und Parodontologie, Forschungslabor für dentale Biomaterialien, Erlangen, Germany
| | - Ulrich Lohbauer
- Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Zahnklinik 1 - Zahnerhaltung und Parodontologie, Forschungslabor für dentale Biomaterialien, Erlangen, Germany
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Maier E, Loumprinis N, Belli R, Petschelt A, Eliades G, Lohbauer U. Fracture toughness of dental incremental composite-composite interfaces at elevated temperatures. J Mech Behav Biomed Mater 2021; 122:104655. [PMID: 34246080 DOI: 10.1016/j.jmbbm.2021.104655] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Revised: 06/16/2021] [Accepted: 06/21/2021] [Indexed: 11/26/2022]
Abstract
The aim of the present laboratory study was to mechanically characterize the interface between two dental resin-based composite (RBC) increments, and to investigate if elevated temperatures have an influence on the quality of the interface mimicking clinical filling procedure. Four RBCs (CLEARFIL MAJESTY™ Posterior, Kuraray (CMP)/Filtek™ Supreme XTE, 3M (FSX)/Grandio®SO, VOCO (GSO)/VisCalor® bulk, VOCO (VCB)) were tested with a fracture toughness test using Chevron notched beams (KI,CNB) at 23, 37 and 54 °C. KI,CNB specimens (3 × 4x25mm) with a V-shaped notch at the incremental interface were loaded until failure in a 4-point bending set-up. Failure modes were characterized using light microscopy, microstructural interface was analyzed using SEM. Statistical analysis was performed using Kolmogorov-Smirnoff test, two-way ANOVA and Tukey Post-Hoc test (p = 0.05). Mean KI,CNB ranged between 0.73 ±0.14 MPam0.5 (VCB, 23 °C) and 1.11 ± 0.11 MPam0.5 (FSX, 23 °C). The tested conventional highly filled RBCs presented fracture toughness at the incremental interface comparable to the cohesive strength of the bulk materials. VCB showed reduced interfacial fracture toughness at 23 and 37 °C, but performed well at elevated temperature of 54 °C.
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Affiliation(s)
- Eva Maier
- Friedrich-Alexander University Erlangen-Nürnberg, Dental Clinic 1 - Operative and Restorative Dentistry, Laboratory for Dental Biomaterials, Glueckstrasse 11, 91054, Erlangen, Germany.
| | - Nikolaos Loumprinis
- Friedrich-Alexander University Erlangen-Nürnberg, Dental Clinic 1 - Operative and Restorative Dentistry, Laboratory for Dental Biomaterials, Glueckstrasse 11, 91054, Erlangen, Germany; National and Kapodistrian University of Athens, Department of Biomaterials, School of Dentistry, 2 Thivon Str, 11527, Goudi, Athens, Greece
| | - Renan Belli
- Friedrich-Alexander University Erlangen-Nürnberg, Dental Clinic 1 - Operative and Restorative Dentistry, Laboratory for Dental Biomaterials, Glueckstrasse 11, 91054, Erlangen, Germany
| | - Anselm Petschelt
- Friedrich-Alexander University Erlangen-Nürnberg, Dental Clinic 1 - Operative and Restorative Dentistry, Laboratory for Dental Biomaterials, Glueckstrasse 11, 91054, Erlangen, Germany
| | - George Eliades
- National and Kapodistrian University of Athens, Department of Biomaterials, School of Dentistry, 2 Thivon Str, 11527, Goudi, Athens, Greece
| | - Ulrich Lohbauer
- Friedrich-Alexander University Erlangen-Nürnberg, Dental Clinic 1 - Operative and Restorative Dentistry, Laboratory for Dental Biomaterials, Glueckstrasse 11, 91054, Erlangen, Germany
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Mechanical degradation of contemporary CAD/CAM resin composite materials after water ageing. Dent Mater 2021; 37:1156-1167. [PMID: 33933272 DOI: 10.1016/j.dental.2021.04.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 03/29/2021] [Accepted: 04/08/2021] [Indexed: 11/22/2022]
Abstract
OBJECTIVE The aim of the present study was to assess the effect of water storage on the quasi-static properties and cyclic fatigue behavior of four contemporary CAD/CAM resin composite materials. METHODS The CAD/CAM resin composites Grandio Blocs, LavaTM Ultimate, CerasmartTM and Brilliant Crios, as well as the direct resin composite Grandio SO, were evaluated. Rectangular plates were cut from the blocks or fabricated using a silicon mold to obtain specimens for fracture toughness (KIc, n = 10), biaxial strength (σ0, n = 30) and cyclic fatigue testing (n = 30). Half of the specimens was stored for 24 h in dry conditions and the other half was aged for 60 days in distilled water at 37 °C. KIc was determined using the Compact-Tension (C(T)) method and σ0 and cyclic fatigue were tested using the Ball-on-Three-Balls assembly. Additional disc-shaped specimens (n = 5) were produced to obtain water sorption curves of the materials. Weibull statistics and two-way ANOVA with Tukey's post-hoc test were used for data assessment. RESULTS The highest water sorption was observed for LavaTM Ultimate (42.6 μg/mm3), whereas Grandio SO displayed the lowest uptake (14 μg/mm3). A statistically significant drop in KIc and σ0 was measured for all materials after water storage, except for the σ0 of CerasmartTM. Water ageing had a dissimilar effect on the cyclic fatigue behavior, increasing the slow crack growth susceptibility of LavaTM Ultimate, but decreasing it for CerasmartTM and Brilliant Crios. SIGNIFICANCE Contemporary CAD/CAM resin composites are susceptible to water driven degradative processes, although differences in filler content and resin matrix constitution play an important role in how it impacts their mechanical properties.
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Determination of Hardness and Fracture Toughness of Y-TZP Manufactured by Digital Light Processing through the Indentation Technique. BIOMED RESEARCH INTERNATIONAL 2021; 2021:6612840. [PMID: 33628793 PMCID: PMC7896846 DOI: 10.1155/2021/6612840] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Revised: 01/09/2021] [Accepted: 01/18/2021] [Indexed: 02/05/2023]
Abstract
Objective The purpose of the study was to determine the hardness and fracture toughness of dental yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) manufactured by digital light processing (DLP) technology to study its clinical prospects. Methods The experimental group was DLP-manufactured zirconia, and the control group was milled zirconia. The hardness was investigated under a range of test loads (0.49 N, 0.98 N, 1.96 N, 4.90 N, 9.81 N, 29.42 N, 49.03 N, 98.07 N, and 196.1 N). Meyer's law was applied to describe the indentation size effect (ISE). Meanwhile, the PSR model and MPSR model were utilized to generate true hardness values. The cracks were observed to be induced by indentation under loads above 49.03 N, while the cracks showed the radial-median type under the load of 196.1 N, under which the fracture toughness was calculated. Results The true hardness of DLP-manufactured zirconia was 1189 HV based on the PSR model and 1193 HV based on the MPSR model, a bit lower than that of milled zirconia. The fracture toughness was 3.43 ± 0.29 MPa√m, which showed no statistical difference with the milled zirconia. Conclusion The dental zirconia manufactured by the DLP 3D printing technique is similar to that manufactured by the conventional milling process in hardness and fracture toughness, thus having a promising future of clinical use.
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Niem T, Gonschorek S, Wöstmann B. New method to differentiate surface damping behavior and stress absorption capacities of common CAD/CAM restorative materials. Dent Mater 2021; 37:e213-e230. [PMID: 33531148 DOI: 10.1016/j.dental.2020.12.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 12/17/2020] [Accepted: 12/30/2020] [Indexed: 01/20/2023]
Abstract
OBJECTIVES To assess energy dissipation capacities and surface damping abilities of different CAD/CAM restorative materials (CRMs) to characterize stress resistance during load peaks. METHODS Using instrumented indentation testing (IIT), Martens hardness (HM) together with its elastic (ηIT) and plastic index (ηITdis) and Leeb hardness (HLD) together with its deduced energy dissipation (HLDdis) were determined for eight ceramic, eight composite, and four polymer-based materials as well as three metals. The results were compared to those of bovine enamel. Ten indentations per material were performed at room temperature (23 ± 1 °C) on two separate specimens (12.0 × 12.0 × 3.5 mm3) after water storage (24 h; 37.0 ± 1.0 °C). Hardness parameters were recorded, and data were analyzed with one-way MANOVA (Games-Howell post hoc tests, α = 0.05). Correlations between different parameters were tested (Pearson, α = 0.05). RESULTS Independently determined HLDdis, and ηITdis values substantiated different energy dissipation characteristics of CRM, whereby a strong correlation was observed for the two datasets (r = 0.956, p = 0.011). Ceramics had the significantly lowest values (p < 0.001) while both parameters revealed the highest surface damping effects for metals (p < 0.001), followed in both cases by bovine enamel. Energy dissipation of polymer and composite CRM was in between ceramics and bovine enamel (p < 0.001), whereas only for HLDdis did both show no significant difference (p > 0.05). SIGNIFICANCE Promising new HLDdis and ηITdis data allow a reliable differentiation of energy dissipation and surface damping capacities of CRMs. Previously published rankings of edge chipping and loss tangent results were perfectly reproduced, especially by HLDdis.
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Affiliation(s)
- Th 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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Spintzyk S, Geis-Gerstorfer J, Bourauel C, Keilig L, Lohbauer U, Brune A, Greuling A, Arnold C, Rues S, Adjiski R, Sawada T, Lümkemann N, Stawarczyk B, Ilie N, Frankenberger R, Dudek MC, Strickstrock M, Begand S. Biaxial flexural strength of zirconia: A round robin test with 12 laboratories. Dent Mater 2020; 37:284-295. [PMID: 33358016 DOI: 10.1016/j.dental.2020.11.016] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 09/02/2020] [Accepted: 11/21/2020] [Indexed: 11/16/2022]
Abstract
OBJECTIVE The aim of this interlaboratory round robin test was to prove the robustness of the DIN EN ISO 6872:2019 and to identify the influence of processing and testing variations. METHODS Each of the 12 laboratories participated (A-L) received 60 (n = 720) assigned zirconia specimens. All participants seperated the specimens from the blanks, sintered them, polished half of all specimens and performed the biaxial flexural test (DIN EN ISO 6872:2019). The surface roughness was determined by using tactile measuring device. Fractographic examination was performed under scanning-electron-microscopy (SEM). Data was analysed using Kolmogorov-Smirnov-, Kruskal-Wallis-, Mann-Whitney-U-test and two-parametric Weibull statistic (p < 0.05). RESULTS The results for both preparation methods (as-fired and polished) showed significant differences for some participants. The values for as-fired groups ranged between 513 (I) and 659 (E) MPa. H showed higher Weibull modulus than C, E and I. Within polished groups flexural strengths values from 465 (L) to 1212 (E) MPa were observed, with a tendency to clustered groups A, I, J, L (465-689 MPa) and remaining groups (877-1212 MPa). E presented the highest and H the lowest Weibull modulus. Within A and J, no impact of the preparation method on flexural strength values was observed. Within L, as-fired specimens showed higher flexural strength than polished ones. The flexural strength increase did only associate to a certain extent with measured surface roughness. Fractography showed defect populations depending on polishing techniques, associated to the strength level, especially for polished groups. Reduced strength is related to machining defects, regardless of the surface state. SIGNIFICANCE DIN EN ISO 6872:2019 can be seen as guidance to biaxial flexural strength testing but additional effort is necessary to ensure interlaboratory comparability. Calibrated furnaces and reliable sintering conditions are mandatory requirements together with detailed specifications on finishing or polishing procedures. Biaxial flexural testing is really a matter of understanding specimen preparation, alignment and mechanical testing by itself. DIN EN ISO 6872:2019 should further recommend reporting of mean surface roughness along with any biaxial flexural strength data. Fractography is a mandatory tool in interpretation and understanding of strength data.
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Affiliation(s)
- Sebastian Spintzyk
- University Hospital Tübingen, Section "Medical Materials Science & Technology", Osianderstr. 2-8, 72076 Tuebingen, Germany.
| | - Jürgen Geis-Gerstorfer
- University Hospital Tübingen, Section "Medical Materials Science & Technology", Osianderstr. 2-8, 72076 Tuebingen, Germany
| | - Christoph Bourauel
- University Hospital Bonn, Oral Technology, School of Dentistry, University of Bonn, Welschnonnenstr. 17, 53111 Bonn, Germany
| | - Ludger Keilig
- University Hospital Bonn, Oral Technology, School of Dentistry, University of Bonn, Welschnonnenstr. 17, 53111 Bonn, Germany
| | - Ulrich Lohbauer
- University of Erlangen-Nuremberg, Dental Clinic 1 - Operative Dentistry and Periodontology, Glueckstrasse 11, 91054 Erlangen, Germany
| | - Annike Brune
- Hannover Medical School, Clinic for Dental Prosthetics, Carl-Neuberg-Straße 1, 30625 Hannover, Germany
| | - Andreas Greuling
- Hannover Medical School, Clinic for Dental Prosthetics, Carl-Neuberg-Straße 1, 30625 Hannover, Germany
| | - Christin Arnold
- Department of Prosthodontics, School of Dental Medicine, Martin-Luther-University, Magdeburger Str. 16, 06112 Halle (Saale), Germany
| | - Stefan Rues
- Department of Prosthodontics, Heidelberg University Hospital, Im Neuenheimer Feld 400, 69120 Heidelberg, Germany
| | - Ranko Adjiski
- Otto Schott Institute of Materials Research, Friedrich Schiller University Jena, Löbdergraben 32, 07743 Jena, Germany
| | - Tomofumi Sawada
- Department of Prosthodontics, University Hospital Tübingen, Osianderstr. 2, -8, 72076 Tübingen, Germany
| | - Nina Lümkemann
- Department of Prosthetic Dentistry, University Hospital, Dental School, Ludwig-Maximilians-University Munich, Goethestraße 70, 80336 Munich, Germany
| | - Bogna Stawarczyk
- Department of Prosthetic Dentistry, University Hospital, Dental School, Ludwig-Maximilians-University Munich, Goethestraße 70, 80336 Munich, Germany
| | - Nicoleta Ilie
- Department of Operative Dentistry and Periodontology, University Hospital, Dental School, Ludwig-Maximilians-University Munich, Goethestraße 70, 80336 Munich, Germany
| | - Roland Frankenberger
- Department of Operative Dentistry, Endodontics and Pediatric Dentistry, Medical Center for Dentistry, University Medical Center Giessen and Marburg, Campus Marburg, Georg-Voigt-Str. 3, 35039 Marburg, Germany
| | - Marie-Christine Dudek
- Department of Operative Dentistry, Endodontics and Pediatric Dentistry, Medical Center for Dentistry, University Medical Center Giessen and Marburg, Campus Marburg, Georg-Voigt-Str. 3, 35039 Marburg, Germany
| | - Monika Strickstrock
- Faculty of Engineering and Computer Science, Material Science and Analysis, University of Applied Sciences Osnabrück, Albrechtstrasse 30, Osnabrück 49076, Germany
| | - Sabine Begand
- Fraunhofer Institute for Ceramics Technologies and Systems IKTS, Michael-Faraday-Str. 1, 07639 Hermsdorf, Germany
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Evaluation of translucency, Marten's hardness, biaxial flexural strength and fracture toughness of 3Y-TZP, 4Y-TZP and 5Y-TZP materials. Dent Mater 2020; 37:212-222. [PMID: 33267975 DOI: 10.1016/j.dental.2020.11.007] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Revised: 07/20/2020] [Accepted: 11/02/2020] [Indexed: 11/20/2022]
Abstract
OBJECTIVES Testing and comparing of different non-shaded zirconia materials (3Y-TZP, 4Y-TZP and 5Y-TZP) on optical and mechanical properties. MATERIALS AND METHODS Zirconia materials (N = 320, Opaque O, Translucent T, Extra Translucent ET, High Translucent HT) were investigated on translucency, Martens parameter, biaxial flexural strength, Chevron-Notch-Beam (CNB) fracture toughness (KIC) and grain size. The grain size was analyzed using a scanning electron microcopy (SEM). Univariate ANOVA, post-hoc Scheffé, partial eta-squared, Kolmogorov-Smirnov-, Kruskal-Wallis- and Mann-Whitney-U-tests (p < 0.05) were performed. The reliability of flexural strength was calculated with two-parametric Weibull analysis and 95 % confidence level. RESULTS The translucency of ET and HT increased with the thermo-mechanical aging (p < 0.001). The zirconia material and aging had no impact on the Martens hardness and the indentation modulus. ET showed the highest flexural strength values after initial and thermo-mechanical aging (p < 0.001 - 0.683). All four materials showed the highest flexural strength after thermo-mechanical aging after 1.2 Mio cycles. Thermo-mechanically (1.2 Mio cycles) aged HT presented the highest Weibull modulus (m = 15.0) regardless of aging. Within initial groups, T (p ≤ 0.001) showed the highest fracture toughness, followed by O (p ≤ 0.001), ET (p < 0.003) and HT (p ≤ 0.001). SIGNIFICANCE Translucency of ET and HT increases with thermo-mechanical aging. Chevron-Notch-Beam (CNB) is a valid alternative to the single-edge-V-notched beam (SEVNB) method for testing fracture toughness.
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Moreira Bastos Campos T, Marques de Melo Marinho R, de Oliveira Pinto Ribeiro A, Larissa do Amaral Montanheiro T, Carolina da Silva A, Thim GP. Microstructure and mechanical properties of fully sintered zirconia glazed with an experimental glass. J Mech Behav Biomed Mater 2020; 113:104093. [PMID: 33022517 DOI: 10.1016/j.jmbbm.2020.104093] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 09/09/2020] [Accepted: 09/14/2020] [Indexed: 10/23/2022]
Abstract
The need for improved mechanical properties in regions of higher masticatory loads led to the introduction of zirconia in dentistry. However, zirconia needs a characterization and glaze to have a more natural, tooth-like appearance. An experimental glass was produced based on the sol-gel method to exhibit a thermal expansion coefficient similar to that presented by zirconia. The experimental glass was used as glazing material on the previously sintered zirconia (vita YZ) surface. There was a significant reduction in the roughness and hardness of the material, caused by the formation of smooth, void-free and highly uniform glass coating. The glass infiltrated among superficial zirconia grains and caused the formation of monoclinic zirconia at the zirconia/glass interface. A consequent decrease in surface roughness and an increase in flexural strength and reliability was then observed in the experimental glass group. On the other hand, a significant decrease in the reliability of conventionally glazed group was observed. Therefore, the use of experimental glass instead of conventional glaze can improve the mechanical properties, smoothness, and mechanical reliability of fully sintered zirconia.
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Affiliation(s)
- Tiago Moreira Bastos Campos
- Physics Department, Aeronautics Technological Institute (ITA), 50 Marechal Eduardo Gomes Square, 12228-900, São José dos Campos, SP, Brazil.
| | - Renata Marques de Melo Marinho
- Department of Dental Materials and Prosthodontics, São Paulo State University (UNESP), Institute of Science and Technology, São José dos Campos, São Paulo, Brazil.
| | - Amanda de Oliveira Pinto Ribeiro
- Department of Dental Materials and Prosthodontics, São Paulo State University (UNESP), Institute of Science and Technology, São José dos Campos, São Paulo, Brazil.
| | - Thais Larissa do Amaral Montanheiro
- Physics Department, Aeronautics Technological Institute (ITA), 50 Marechal Eduardo Gomes Square, 12228-900, São José dos Campos, SP, Brazil.
| | - Ana Carolina da Silva
- Department of Dental Materials and Prosthodontics, São Paulo State University (UNESP), Institute of Science and Technology, São José dos Campos, São Paulo, Brazil.
| | - Gilmar Patrocínio Thim
- Physics Department, Aeronautics Technological Institute (ITA), 50 Marechal Eduardo Gomes Square, 12228-900, São José dos Campos, SP, Brazil.
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Cokic SM, Vleugels J, Van Meerbeek B, Camargo B, Willems E, Li M, Zhang F. Mechanical properties, aging stability and translucency of speed-sintered zirconia for chairside restorations. Dent Mater 2020; 36:959-972. [PMID: 32493658 DOI: 10.1016/j.dental.2020.04.026] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 04/10/2020] [Accepted: 04/30/2020] [Indexed: 12/01/2022]
Abstract
OBJECTIVE To evaluate the performance of zirconia ceramics sintered in a speed sintering induction furnace by comprehensive understanding of their optical and mechanical properties, microstructure, phase composition and aging stability, in comparison to ceramics sintered in a conventional furnace. METHODS Speed sintered (SS) Katana STMLSS (Kuraray Noritake) (total thermal cycle/sintering time/dwell temperature: 30min/16min/1560°C) and CEREC Zirconia (CEREC ZrSS) (Dentsply Sirona) (15min/2min/1578°C) were compared to conventionally sintered (CS) Katana STMLCS (6.8h/2h/1550°C) and inCoris TZICS (4h/2h/1510°C). The translucency parameter (TP) and contrast ratio (CR) were measured with a spectrophotometer. The chemical composition of the materials was determined by XRF and phase composition was characterized using XRD. Hydrothermal aging behavior was evaluated by measuring the tetragonal-to-monoclinic ZrO2 phase transformation after accelerated hydrothermal aging in steam at 134°C. The indentation fracture toughness, Vickers hardness and biaxial strength of the sintered ceramics were assessed. RESULTS Speed and conventionally sintered zirconia revealed similar density, microstructure, average strength and hydrothermal aging stability. Both Katana STMLSS/CS 5Y-PSZ ceramics were characterized with a higher content of cubic phase (≈53wt%), which resulted in a higher amount of Y2O3 in the remaining tetragonal ZrO2 phases compared to the 3Y-TZP CEREC ZrSS and inCoris TZICS (8 and 20wt%, respectively). The sintering program did not affect the hydrothermal aging behavior of Katana STMLSS and CEREC ZrSS. TP of Katana STMLSS (TP≈32) was not affected by speed sintering, while the translucency of CEREC ZrSS (TP=14) was significantly reduced. Hardness, fracture toughness and Weibull characteristic strength of Katana STMLSS and CEREC ZrSS also reached the optimal level, but speed sintering substantially lowered their mechanical reliability. SIGNIFICANCE Speed sintering of 3Y-TZP and 5Y-PSZ in a speed sintering induction oven appeared suitable for clinical applications. However, further studies should focus on improving of translucency and mechanical reliability of the speed-sintered zirconia ceramics.
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Affiliation(s)
- Stevan M Cokic
- KU Leuven (University of Leuven), Department of Oral Health Sciences, BIOMAT & UZ Leuven (University Hospitals Leuven), Dentistry, Leuven, Belgium
| | - Jef Vleugels
- KU Leuven (University of Leuven), Department of Materials Engineering (MTM), Kasteelpark Arenberg 44, B-3001 Leuven, Belgium
| | - Bart Van Meerbeek
- KU Leuven (University of Leuven), Department of Oral Health Sciences, BIOMAT & UZ Leuven (University Hospitals Leuven), Dentistry, Leuven, Belgium.
| | - Bernardo Camargo
- KU Leuven (University of Leuven), Department of Oral Health Sciences, BIOMAT & UZ Leuven (University Hospitals Leuven), Dentistry, Leuven, Belgium
| | - Evita Willems
- KU Leuven (University of Leuven), Department of Materials Engineering (MTM), Kasteelpark Arenberg 44, B-3001 Leuven, Belgium
| | - Maoyin Li
- KU Leuven (University of Leuven), Department of Materials Engineering (MTM), Kasteelpark Arenberg 44, B-3001 Leuven, Belgium
| | - Fei Zhang
- KU Leuven (University of Leuven), Department of Oral Health Sciences, BIOMAT & UZ Leuven (University Hospitals Leuven), Dentistry, Leuven, Belgium; KU Leuven (University of Leuven), Department of Materials Engineering (MTM), Kasteelpark Arenberg 44, B-3001 Leuven, Belgium
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STAWARCZYK B, LIEBERMANN A, ROSENTRITT M, POVEL H, EICHBERGER M, LÜMKEMANN N. Flexural strength and fracture toughness of two different lithium disilicate ceramics. Dent Mater J 2020; 39:302-308. [DOI: 10.4012/dmj.2019-045] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- Bogna STAWARCZYK
- Department of Prosthetic Dentistry, University Hospital, Ludwig-Maximilians-University Munich
| | - Anja LIEBERMANN
- Department of Prosthetic Dentistry, University Hospital, Ludwig-Maximilians-University Munich
| | | | - Hubertus POVEL
- Department of Prosthetic Dentistry, University Hospital, Ludwig-Maximilians-University Munich
| | - Marlis EICHBERGER
- Department of Prosthetic Dentistry, University Hospital, Ludwig-Maximilians-University Munich
| | - Nina LÜMKEMANN
- Department of Prosthetic Dentistry, University Hospital, Ludwig-Maximilians-University Munich
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Stawarczyk B, Dinse L, Eichberger M, Jungbauer R, Liebermann A. Flexural strength, fracture toughness, three-body wear, and Martens parameters of pressable lithium-X-silicate ceramics. Dent Mater 2020; 36:420-430. [PMID: 32007315 DOI: 10.1016/j.dental.2020.01.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Revised: 11/26/2019] [Accepted: 01/14/2020] [Indexed: 11/24/2022]
Abstract
OBJECTIVES To test and compare five pressable lithium-X-silicate-ceramics on their mechanical and wear properties. METHODS Specimens were pressed and prepared from: i. Amber Press (AP), ii. Celtra Press (CP), iii. Initial LiSi Press (IL), iv. Livento Press (LP), and v. IPS e.max Press (IE). Four-point flexural strength (FS), SEVNB fracture toughness (KIC), three-body wear (3BW), Martens hardness (HM) and indentation modulus (EIT) were measured. For CP, FS and HM were measured with and without additional Power Firing. Each subgroup contained 15 specimens. Data were analyzed using Kolmogorov-Smirnov, one-way ANOVA followed by Scheffé test, Kruskal-Wallis-H-, Mann-Whitney-U-, and Spearman-Rho-test (p < 0.05). The Weibull modulus was calculated using the maximum likelihood estimation method. RESULTS AP and CP presented higher FS than IL. LP presented the highest Weibull modulus. CP showed lower KIC values than AP, and AP was not significant compared to LP and IE. The most 3BW material loss was observed for CP. CP revealed higher HM values than the remaining ceramics. IL presented lower EIT compared to AP and CP. The following correlations were observed between the test parameters: 3BW with FS (r = 0.279, p = 0.015), with HM (r = -0.378, p = 0.001), and with EIT (r = -0.344, p = 0.004); EIT with FS (r = 0.203, p = 0.028); and HM with FT (r = -0.223, p = 0.027) and EIT (r = 0.884, p < 0.001). No correlations were observed between FS and KIC (r = 0.046; p = 0.346). SIGNIFICANCE AP followed by LP showed the highest and IL followed by CP the lowest properties tested. Power Firing of CP improved the flexural strength. Ceramics with high flexural strength and Martens parameters showed lower wear. Materials with high Martens hardness presented lower fracture toughness values and ones with high indentation modulus showed high flexural strength.
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Affiliation(s)
- Bogna Stawarczyk
- Department of Prosthetic Dentistry, University Hospital, LMU Munich, 80336 Munich, Germany.
| | - Lina Dinse
- Department of Prosthetic Dentistry, University Hospital, LMU Munich, 80336 Munich, Germany
| | - Marlis Eichberger
- Department of Prosthetic Dentistry, University Hospital, LMU Munich, 80336 Munich, Germany
| | - Rebecca Jungbauer
- Department of Prosthetic Dentistry, University Hospital, LMU Munich, 80336 Munich, Germany
| | - Anja Liebermann
- Department of Prosthetic Dentistry, University Hospital, LMU Munich, 80336 Munich, Germany
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Tzanakakis E, Kontonasaki E, Voyiatzis G, Andrikopoulos K, Tzoutzas I. Surface characterization of monolithic zirconia submitted to different surface treatments applying optical interferometry and raman spectrometry. Dent Mater J 2019; 39:111-117. [PMID: 31611497 DOI: 10.4012/dmj.2018-358] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
This study evaluated roughness parameters and phase transformation of monolithic zirconia ceramics after various mechanical and laser thermal treatments. Fully sintered monolithic zirconia cylinder specimens were divided to five groups, according to the applied surface treatment: CL: control, GB: grit-blasted with glass particles. AL50: grit-blasted with 50 μm alumina particles, AL90: grit-blasted with 90 μm dyed-alumina particles and FEML: subjected to femto laser thermal treatment. Six roughness parameters (Sa, Sq, Sz, Sci, Svi and Sdr) were measured by optical profilometry. Phase transformation in zirconia was determined by micro-Raman spectroscopy. The highest roughness values were recorded in AL90 and FEML groups, followed by AL50. AL90 presented statistically higher monoclinic phase content compared to all other groups. Control and GB groups presented similar roughness without phase transformation. Laser thermal treatment causes minimal destruction of the zirconia surface, and can be suggested as an alternative to other roughening treratments, for enhancing the adhesive potential to dentin.
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Affiliation(s)
| | - Eleana Kontonasaki
- Department of Fixed Prosthesis & Implant Prosthodontics, University of Thessaloniki University Campus, Dentistry Building
| | - George Voyiatzis
- Foundation for Research and Technology, Hellas-Institute of Chemical Engineering Sciences (FORTH/ICE-HT)
| | - Konstantinos Andrikopoulos
- Foundation for Research and Technology, Hellas-Institute of Chemical Engineering Sciences (FORTH/ICE-HT)
| | - Ioannis Tzoutzas
- Department of Operative Dentistry, University of Athens School of Dentistry
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Jansen JU, Lümkemann N, Letz I, Pfefferle R, Sener B, Stawarczyk B. Impact of high-speed sintering on translucency, phase content, grain sizes, and flexural strength of 3Y-TZP and 4Y-TZP zirconia materials. J Prosthet Dent 2019; 122:396-403. [DOI: 10.1016/j.prosdent.2019.02.005] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Revised: 02/19/2019] [Accepted: 02/19/2019] [Indexed: 01/24/2023]
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JANSEN JU, LÜMKEMANN N, SENER B, STAWARCZYK B. Comparison of fracture toughness measurements for zirconia materials using two test methods. Dent Mater J 2019; 38:806-812. [DOI: 10.4012/dmj.2018-361] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- Jan Ulrich JANSEN
- Department of Prosthetic Dentistry, Dental Material Unit, Ludwig-Maximilians-University Munich
| | - Nina LÜMKEMANN
- Department of Prosthetic Dentistry, Dental Material Unit, Ludwig-Maximilians-University Munich
| | - Beatrice SENER
- Periodontics and Cardiology, Clinic for Preventive Dentistry, University of Zurich
| | - Bogna STAWARCZYK
- Department of Prosthetic Dentistry, Dental Material Unit, Ludwig-Maximilians-University Munich
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Straface A, Rupp L, Gintaute A, Fischer J, Zitzmann NU, Rohr N. HF etching of CAD/CAM materials: influence of HF concentration and etching time on shear bond strength. Head Face Med 2019; 15:21. [PMID: 31395069 PMCID: PMC6686502 DOI: 10.1186/s13005-019-0206-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Accepted: 07/29/2019] [Indexed: 11/29/2022] Open
Abstract
Background The required pretreatment of CAD/CAM ceramic materials before resin composite cement application varies among studies. The aim of the present study was to evaluate the effect of hydrofluoric acid concentration and etching time on the shear bond strength (SBS) of two adhesive and two self-adhesive resin composite cements to different CAD/CAM ceramic materials. Methods SBS of two adhesive (Panavia V5, Kuraray, [PV5]; Vita Adiva F-Cem, Vita Zahnfabrik, [VAF]) and two self-adhesive (RelyX Unicem 2 Automix, 3 M Espe, [RUN]; Vita Adiva S-Cem, Vita, [VAS]) cements to four different CAD/CAM materials (Vitablocs Mark II, Vita, [VM]; Vita Enamic, Vita, [VE]; e.max CAD, Ivoclar Vivadent, [EC]; Vita Suprinity PC, Vita, [VS]) was measured. The effect of the surface pretreatment by using two different hydrofluoric acid products (HF5% Vita Ceramics Etch, Vita and HF9% buffered, Ultradent Porcelain Etch, Ultradent Products) were assessed at etching times of 0 s, 5 s, 15 s, 30s and 60s for each cement and restorative material combination (n = 10 per group, total n = 1440). Results Significant effects were found for the etching time and cement for all materials with highest shear bond strength for etching times of 60s = 30s = 15 s ≥ 5 s > 0 s and for RUN>PV5 = VAF > VAS (p < 0.05). Etching with HF5% for 5 s to 15 s resulted in higher SBS values, while no differences were observed between HF5% and HF9% buffered when the substrates were etched for 30s to 60s (p < 0.05). Conclusions Within the limitations of this study the recommended surface pretreatment of silicate ceramics is HF etching with concentrations of 5% or 9% for 15 s to 60s to achieve highest shear bond strength while the glassy matrix is sufficiently dissolved. The tested resin composite cements can be applied with all tested materials and suggested for clinical application.
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Affiliation(s)
- Antonio Straface
- Department of Reconstructive Dentistry, University Center for Dental Medicine, University of Basel, Mattenstrasse 40, CH-4058, Basel, Switzerland
| | - Lena Rupp
- Department of Reconstructive Dentistry, University Center for Dental Medicine, University of Basel, Mattenstrasse 40, CH-4058, Basel, Switzerland
| | - Aiste Gintaute
- Department of Reconstructive Dentistry, University Center for Dental Medicine, University of Basel, Mattenstrasse 40, CH-4058, Basel, Switzerland
| | - Jens Fischer
- Department of Reconstructive Dentistry, University Center for Dental Medicine, University of Basel, Mattenstrasse 40, CH-4058, Basel, Switzerland
| | - Nicola U Zitzmann
- Department of Reconstructive Dentistry, University Center for Dental Medicine, University of Basel, Mattenstrasse 40, CH-4058, Basel, Switzerland
| | - Nadja Rohr
- Department of Reconstructive Dentistry, University Center for Dental Medicine, University of Basel, Mattenstrasse 40, CH-4058, Basel, Switzerland.
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Lohbauer U, Belli R, Abdalla Alonso A, Goetz-Neunhoeffer F, Hurle K. Effect of sintering parameters on phase evolution and strength of dental lithium silicate glass-ceramics. Dent Mater 2019; 35:1360-1369. [PMID: 31377060 DOI: 10.1016/j.dental.2019.07.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Revised: 06/05/2019] [Accepted: 07/08/2019] [Indexed: 11/18/2022]
Abstract
OBJECTIVE With the establishment of CAD/CAM technology, competing lithium silicate based formulations have been introduced for clinical use, but little is known about their phase composition. Here we investigate a commercially available SiO2-Al2O3-K2O-Li2O-P2O5-ZrO2 system to evaluate the crystal phase evolution during the second heat treatment by changing the main crystallization parameters. METHODS With a focus on the final stage of crystallization, we characterized the dimensional changes in the crystallographic structure of the residual Li2SiO3 and the lithium orthophosphate (Li3PO4) phases with variations in crystallization parameters, i.e. time, temperature and cooling rate over the range of the glass transition temperature Tg. The phase fractions (crystalline and glass) and the sizes of coherent scattering domains (CSDs) were resolved by means of quantitative X-Ray Diffraction using Rietveld refinement combined with an external standard method (G-factor). Biaxial flexure testing was conducted to evaluate the influence of crystallization parameters on the characteristic strength and natural defect distribution. RESULTS An increase in crystallization temperature from 840 to 880°C resulted in a significant reduction of the Li2Si2O5 content, which indicated a reversion of the Li2SiO3 to Li2Si2O5 phase transformation. Reduction to 800°C had no significant effect. Furthermore, the CSD sizes of Li2SiO3 and Li3PO4 continuously increased with increasing temperature, which was accompanied by an increase in strength parameters. Reducing the cooling rate over the range of Tg resulted in an increased strength at low failure probabilities. SIGNIFICANCE These findings help to establish recommendations for adjustment of the crystallization protocol, which has potential to increase the clinical reliability of the material investigated.
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Affiliation(s)
- Ulrich Lohbauer
- Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Zahnklinik 1 - Zahnerhaltung und Parodontologie, Forschungslabor für dentale Biomaterialien, Glueckstrasse 11, 91054 Erlangen, Germany
| | - Renan Belli
- Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Zahnklinik 1 - Zahnerhaltung und Parodontologie, Forschungslabor für dentale Biomaterialien, Glueckstrasse 11, 91054 Erlangen, Germany.
| | - Alexandre Abdalla Alonso
- São Paulo State University (Unesp), Institute of Science and Technology, São José dos Campos, Brazil
| | - Friedlinde Goetz-Neunhoeffer
- Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), GeoZentrum Nordbayern, Lehrstuhl für Mineralogie, Schlossgarten 5a, 91054 Erlangen, Germany
| | - Katrin Hurle
- Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), GeoZentrum Nordbayern, Lehrstuhl für Mineralogie, Schlossgarten 5a, 91054 Erlangen, Germany
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Hampe R, Theelke B, Lümkemann N, Eichberger M, Stawarczyk B. Fracture Toughness Analysis of Ceramic and Resin Composite CAD/CAM Material. Oper Dent 2019; 44:E190-E201. [DOI: 10.2341/18-161-l] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
SUMMARY
Objectives:
To evaluate and compare the fracture toughness of dental CAD/CAM materials of different material classes intended for in-office milling (glass ceramics, hybrid, resin composites) and the influence of aging on this property.
Methods and Materials:
The fracture toughness (critical intensity factor, KIc) values of 9 CAD/CAM restorative materials (Ambarino High-Class, Brilliant Crios, Cerasmart, exp. CAD/CAM composite, Katana Avencia, Lava Ultimate, VITA Enamic, IPS Empress CAD, and IPS e.max CAD) were determined using the SEVNB method in a four-point bending setup. Twenty bending bars of each material with a 4 × 3 cross and a minimum length of 12 mm were cut out of CAD/CAM milling blocks. Notching was done starting with a pre-cut and consecutive polishing and v-shaping with a razor blade, resulting in a final depth of v-shaped notches of between 0.8 and 1.2 mm. Half of the specimens were selected for initial fracture toughness measurements. The others were thermocycled in distilled water for 30,000× (5/55°C; 30-second dwell time) before testing. Specimen fracture surfaces were analyzed using confocal laser scanning microscopy.
Results:
All specimens for each material fractured into two fragments and showed the typical compression curl and brittle failure markings. Comparing initial KIc values, lithium disilicate ceramic IPS e.max CAD showed significantly the highest and leucite-reinforced ceramic IPS Empress CAD significantly the lowest KIc values (p<0.001). All tested CAD/CAM materials with a resin component ranged in the same KIc value group (p>0.999-0.060). After thermal cycling, the highest KIc values were measured for lithium disilicate ceramic IPS e.max CAD, followed by resin composite materials Ambarino High-Class (p<0.001-0.006) and hybrid material VITA Enamic (p<0.001-0.016), while the significantly lowest values were reflected for the resin composite materials Cerasmart, LAVA Ultimate (p<0.001-0.006), and Katana Avencia (p<0.001-0.009). The roughness of the fracture surfaces varied depending on the microstructure of the respective material. The ceramic surfaces showed the smoothest surfaces. The fracture surface of VITA Enamic revealed microstructural inhomogeneities and microcracks. For CAD/CAM resin composite materials, crack paths through the matrix and interfaces of matrix and fillers could be observed at the microstructure level.
Conclusions:
The materials tested show differences in fracture toughness typical for the class they belong to. With one exception (Ambarino High-Class), thermocycling affected the fracture toughness of materials with a resin component negatively, whereas the leucite and lithium disilicate ceramic showed stability.
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Affiliation(s)
- R Hampe
- Rüdiger Hampe, Dipl-Ing (FH), MSc, Department of Prosthetic Dentistry, University Hospital, LMU Munich, Munich, Germany
| | - B Theelke
- Björn Theelke, Dipl-Ing (FH), School of Metallurgy and Materials, University of Birmingham, Birmingham, UK
| | - N Lümkemann
- Nina Lümkemann, MSc, Department of Prosthetic Dentistry, University Hospital, LMU Munich, Munich, Germany
| | - M Eichberger
- Marlis Eichberger, CDT, Department of Prosthodontics, Dental School Ludwig-Maximilians-University, Munich, Germany
| | - B Stawarczyk
- Bogna Stawarczyk, PhD, Dr Dipl-Ing (FH), MSc, Department of Prosthetic Dentistry, University Hospital, LMU Munich, Munich, Germany
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Alshabib A, Silikas N, Watts DC. Hardness and fracture toughness of resin-composite materials with and without fibers. Dent Mater 2019; 35:1194-1203. [PMID: 31176452 DOI: 10.1016/j.dental.2019.05.017] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2019] [Revised: 05/16/2019] [Accepted: 05/16/2019] [Indexed: 10/26/2022]
Abstract
OBJECTIVE To investigate the surface micro-hardness (VHN) and fracture toughness (KIC) of resin-composites, with and without incorporated short fibers, after solvent storage. METHODS Three resin-composites incorporating fibers, additional to particle reinforcement, were examined: everX™, NovoPro Fill™ and NovoPro Flow™. Four composites were used as controls, with only particle reinforcement: Filtek bulk Fill™, Filtek bulk one™, Filtek XTE™, and Filtek Flow XTE™. For hardness measurement, materials were cured in 2mm thick molds for 20s by a LED source of average irradiance 1.2W/cm2. Specimens (n=6/group) were stored dry for 1h and then in either water or 75% ethanol/water for 1h, 1 day and 30 days at 37±1°C. Vickers hardness was measured under a load of 300g for 15s. For fracture toughness (KIC) measurements, single-edge-notched specimens (n=6/group) were prepared: (32×6×3mm) for 3-point bending and stored for 1 and 7 days in water at 37°C. Fractured surfaces of fiber-reinforced composite were examined by scanning electron microscopy (SEM). VHN data were analyzed using three-way ANOVA, one-way ANOVA and the Tukey post hoc test (p≤0.05). KIC data were analyzed by two-way ANOVA and one-way ANOVA and the Tukey post hoc test (p≤0.05). An independent t-test was used to detect differences (α=0.05) in KIC between stored groups for each material. RESULTS VHN decreased for all composites with storage time in both solvents, but more appreciably in 75% ethanol/water (an average of 20%). KIC ranged from 2.14 (everX Posterior) to 0.96 NovoPro Flow) MPa.m0.5. The longer storage period (7 days) had no significant effect on this property relative to 1 day storage. SIGNIFICANCE Reinforcement with short fibers, and possibly matrix compositional differences, significantly enhanced the fracture toughness of EVX. However, for nano-fiber containing composites, there were no evident beneficial effects upon either their fracture toughness or hardness compared to a range of control composites. Water storage for 7 days of all these resin-composites produced no significant change in their KIC values, relative to 1 day storage.
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Affiliation(s)
- Abdulrahman Alshabib
- School of Medical Sciences, Division of Dentistry, University of Manchester, UK; Department of Restorative Dentistry, College of Dentistry, King Saud University, Riyadh, Saudi Arabia
| | - Nick Silikas
- School of Medical Sciences, Division of Dentistry, University of Manchester, UK.
| | - David C Watts
- School of Medical Sciences, Division of Dentistry, University of Manchester, UK.
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Crack-healing during two-stage crystallization of biomedical lithium (di)silicate glass-ceramics. Dent Mater 2019; 35:1130-1145. [PMID: 31133402 DOI: 10.1016/j.dental.2019.05.013] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Revised: 04/03/2019] [Accepted: 05/07/2019] [Indexed: 12/13/2022]
Abstract
OBJECTIVE The study is aimed to evaluate the two single commercially available two-step lithium-(di)silicate systems by analyzing their parent glass composition and studying the quantitative crystalline and glass phase evolution during the second stage heat-treatment. The mechanical repercussions of the crystallization firing were evaluated using strength and fracture toughness tests. METHODS XRF and ICP-OES were used to determine the oxide composition of the parent glasses in Suprinity PC (Vita Zahnfabrik) and IPS e.max CAD (Ivoclar-Vivadent). The crystalline phase of both materials was determined by quantitative XRD and the G-factor method in the partially and post-crystallization states. The oxide composition of the residual glass phase was derived by subtracting the chemistry of the crystalline phase fractions from the parent glass composition. Mechanical testing of biaxial flexural strength and fracture toughness were used to demonstrate how crack-like defects behave during crystallization. RESULTS The two tested lithium (di)silicate systems showed strong differences in oxide composition of the parent glass. This showed to influence the transformation of lithium metasilicate in lithium disilicate, with the former remaining in high vol.% fraction in the post-crystallization Suprinity PC. In IPS e.max CAD cristobalite precipitated at the surface during the second-heat treatment. Strength and fracture toughness tests revealed that crack in both materials, whether introduced by grinding or indentation, heal during the crystallization firing. Cristobalite seemed to have contributed to a surface strengthening effect in IPS e.max CAD. SIGNIFICANCE Accurate crystalline phase quantification aids in the determination of the residual glass composition in dental glass-ceramics. For both systems crystallization firing induced healing of cracks generated by CAM grinding.
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The potential of three-dimensional printing technologies to unlock the development of new ‘bio-inspired’ dental materials: an overview and research roadmap. J Prosthodont Res 2019; 63:131-139. [DOI: 10.1016/j.jpor.2018.10.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Revised: 10/05/2018] [Accepted: 10/26/2018] [Indexed: 11/23/2022]
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Khosravani MR. Mechanical behavior of restorative dental composites under various loading conditions. J Mech Behav Biomed Mater 2019; 93:151-157. [PMID: 30798181 DOI: 10.1016/j.jmbbm.2019.02.009] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2018] [Revised: 02/07/2019] [Accepted: 02/11/2019] [Indexed: 12/12/2022]
Abstract
Mechanical engineering and its scientific principles constitute an essential core in medical science. Currently, different composite resins are widely used as restorative dental materials. However, their lack of adequate strength and toughness has led to research that is aimed at improving the mechanical properties of dental composites. In the present study, the behavior of three different dental materials is investigated under static and dynamic loading conditions. In the experimental tests, a split Hopkinson pressure bar is utilized which corresponds to the most commonly used experimental setup for examining material behavior under a high rate of loading. The examined dental composites experience impacts during their service life and also during car accidents or sport injuries. Hence, in the study, impact loading is modeled in an experiment. A series of compression tests is conducted from low to high strain rates up to 40s-1, and the dynamic elastic moduli of three different dental composites are measured. Furthermore, studies on the compressed surface of the dental composite specimens are performed to improve the analysis with respect to the hardness of the materials. The responses of the examined composites to dynamic loadings verify the impact resistance of the materials. The results indicate the load-carrying capabilities of the dental composites. These results can be used for materials development and existing computational models.
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Pereira GKR, Dutra DM, Werner A, Prochnow C, Valandro LF, Kleverlaan CJ. Effect of zirconia polycrystal and stainless steel on the wear of resin composites, dentin and enamel. J Mech Behav Biomed Mater 2019; 91:287-293. [PMID: 30611925 DOI: 10.1016/j.jmbbm.2018.12.024] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Revised: 12/17/2018] [Accepted: 12/20/2018] [Indexed: 10/27/2022]
Abstract
This study evaluated the effect of two antagonist substrates (Y-TZP/zirconia or stainless steel) on the wear rate and surface alterations of different composite materials and bovine tooth substrates (enamel and dentin). The wear rate of different composite materials (n = 20; two direct composite resins: HelioMolar - HM; Clearfil AP-X - CAP, three indirect composite resins: Estenia C&B - EST; Adoro - ADO; Sinfony - SFY, and one composite resin for direct/indirect restorations: Filtek Z250 - Z250), bovine enamel and dentin against two different antagonist materials (zirconia or stainless steel) into two mediums (two-body and three-body wear) were collected. After wear tests on ACTA wear machine, Scanning Electron Microscopy (SEM) analysis was performed to access the surface alterations. The wear data were evaluated by three-way ANOVA and Tukey post-hoc test (α = 0.05). The factors 'antagonist', 'medium', 'restorative materials', and the interaction of all factors grouped by two and integrated showed statistical significance on the wear rates. A two-body test depicted no difference among all composites and enamel for wear rate, while a three-body test depicted differences among composites directly related to the filler content: EST < Z250 = CAP < ADO = HM < SFY. Dentin always showed the highest wear rates and enamel the lowest rates. The presence of food bolus (three-body test) led to higher wear rates in comparison to an only aqueous medium (two-body test). SEM analysis showed that different materials present specific wear patterns, regardless of the medium and the antagonist considered. Differently from enamel, dentin substrate was intensively prone to wear, regardless of the antagonist/medium. Resin composite substrates presented intermediate wear rates, depending directly on their filler content (% in weight).
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Affiliation(s)
- Gabriel Kalil Rocha Pereira
- MSciD Graduate Program, School of Dentistry, Meridional Faculty - IMED, Passo Fundo, Rio Grande do Sul State, Brazil.
| | - Danilo Milbradt Dutra
- MSciD-PhD Postgraduate Program, Faculty of Odontology, Federal University of Santa Maria, Santa Maria, Rio Grande do Sul State, Brazil.
| | - Arie Werner
- Academic Centre for Dentistry Amsterdam (ACTA), Department of Dental Materials Science, University of Amsterdam and Vrije Universiteit Amsterdam, Amsterdam, the Netherlands.
| | - Catina Prochnow
- MSciD-PhD Postgraduate Program, Faculty of Odontology, Federal University of Santa Maria, Santa Maria, Rio Grande do Sul State, Brazil.
| | - Luiz Felipe Valandro
- MSciD-PhD Postgraduate Program, Faculty of Odontology, Federal University of Santa Maria, Santa Maria, Rio Grande do Sul State, Brazil.
| | - Cornelis Johannes Kleverlaan
- Academic Centre for Dentistry Amsterdam (ACTA), Department of Dental Materials Science, University of Amsterdam and Vrije Universiteit Amsterdam, Amsterdam, the Netherlands.
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Liu Z, Weng Z, Zhai ZF, Huang N, Zhang ZJ, Tan J, Jiang C, Jiao D, Tan G, Zhang J, Jiang X, Zhang Z, Ritchie RO. Hydration-induced nano- to micro-scale self-recovery of the tooth enamel of the giant panda. Acta Biomater 2018; 81:267-277. [PMID: 30273740 DOI: 10.1016/j.actbio.2018.09.053] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Revised: 08/17/2018] [Accepted: 09/27/2018] [Indexed: 11/19/2022]
Abstract
The tooth enamel of vertebrates comprises a hyper-mineralized bioceramic, but is distinguished by an exceptional durability to resist impact and wear throughout the lifetime of organisms; however, enamels exhibit a low resistance to the initiation of large-scale cracks comparable to that of geological minerals based on fracture mechanics. Here we reveal that the tooth enamel, specifically from the giant panda, is capable of developing durability through counteracting the early stage of damage by partially recovering its innate geometry and structure at nano- to micro- length-scales autonomously. Such an attribute results essentially from the unique architecture of tooth enamel, specifically the vertical alignment of nano-scale mineral fibers and micro-scale prisms within a water-responsive organic-rich matrix, and can lead to a decrease in the dimension of indent damage in enamel introduced by indentation. Hydration plays an effective role in promoting the recovery process and improving the indentation fracture toughness of enamel (by ∼73%), at a minor cost of micro-hardness (by ∼5%), as compared to the dehydrated state. The nano-scale mechanisms that are responsible for the recovery deformation, specifically the reorientation and rearrangement of mineral fragments and the inter- and intra-prismatic sliding between constituents that are closely related to the viscoelasticity of organic matrix, are examined and analyzed with respect to the structure of tooth enamel. Our study sheds new light on the strategies underlying Nature's design of durable ceramics which could be translated into man-made systems in developing high-performance ceramic materials. STATEMENT OF SIGNIFICANCE: Tooth enamel plays a critical role in the function of teeth by providing a hard surface layer to resist wear/impact throughout the lifetime of organisms; however, such enamel exhibits a remarkably low resistance to the initiation of large-scale cracks, of hundreds of micrometers or more, comparable to that of geological minerals. Here we reveal that tooth enamel, specifically that of the giant panda, is capable of partially recovering its geometry and structure to counteract the early stages of damage at nano- to micro-scale dimensions autonomously. Such an attribute results essentially from the architecture of enamel but is markedly enhanced by hydration. Our work discerns a series of mechanisms that lead to the deformation and recovery of enamel and identifies a unique source of durability in the enamel to accomplish this function. The ingenious design of tooth enamel may inspire the development of new durable ceramic materials in man-made systems.
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Affiliation(s)
- Zengqian Liu
- Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China; Department of Materials Science and Engineering, University of California Berkeley, Berkeley, CA 94720, USA
| | - Zhaoyong Weng
- Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China
| | - Zhao-Feng Zhai
- Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China
| | - Nan Huang
- Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China
| | - Zhen-Jun Zhang
- Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China
| | - Jun Tan
- Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China
| | - Chuanbin Jiang
- Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China
| | - Da Jiao
- Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China
| | - Guoqi Tan
- Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China; School of Materials Science and Engineering, University of Science and Technology of China, Hefei 230026, China
| | - Jian Zhang
- Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China; State Key Laboratory of Advanced Non-ferrous Materials, Lanzhou University of Technology, Lanzhou 730050, China
| | - Xin Jiang
- Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China
| | - Zhefeng Zhang
- Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China.
| | - Robert O Ritchie
- Department of Materials Science and Engineering, University of California Berkeley, Berkeley, CA 94720, USA.
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Chung YJ, Park JM, Kim TH, Ahn JS, Cha HS, Lee JH. 3D Printing of Resin Material for Denture Artificial Teeth: Chipping and Indirect Tensile Fracture Resistance. MATERIALS 2018; 11:ma11101798. [PMID: 30248955 PMCID: PMC6213768 DOI: 10.3390/ma11101798] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 09/19/2018] [Accepted: 09/20/2018] [Indexed: 01/11/2023]
Abstract
3D printing of denture artificial teeth with resin materials is worthy of study in a novel way. This study evaluated chipping and indirect tensile fracture resistance of 3D printing resin material (Dentca 3D printing denture teeth resin) compared with conventionally prefabricated resin denture teeth (Premium-8, Surpass, SR-Orthosit-PE, and Preference). One hundred tooth specimens were prepared for testing. The 3D printed tooth specimens were printed at a 50 µm layer thickness with methacrylate-based photopolymerized resin by stereolithography 3D printing. Chipping and indirect tensile fracture tests were conducted at a speed of 1 mm/min until fracture. The indirect tensile fracture loads of the 3D printed resin teeth were higher than those of Premium-8, Surpass, and SR-Orthosit-PE, and lower than those of Preference teeth. Regarding chipping resistance, the 3D printed resin teeth were not different from Surpass and SR-Orthosit-PE, and were lower than Premium-8 and Preference teeth. The 3D printed resin teeth exhibited vertical fracture of the loaded cusp without deformation in chipping. The 3D printed resin teeth showed simultaneous fracture of two cusps in indirect tensile fracture, unlike other teeth. The results of this study suggest that 3D printing technology using resin materials provides adequate fracture resistance for denture artificial tooth use.
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Affiliation(s)
- Yoo-Jin Chung
- Division of Prosthodontics, Department of Dentistry, Asan Medical Center, 88 Olympic-ro 43-gil, Songpa-gu, Seoul 05505, Korea.
| | - Ji-Man Park
- Department of Prosthodontics, College of Dentistry, Yonsei University, 250 Seongsanno, Seodaemun-gu, Seoul 03722, Korea.
| | - Tae-Hyung Kim
- Division of Restorative Sciences, Herman Ostow School of Dentistry of University of Southern California, Los Angeles, CA 90089-0641, USA.
| | - Jin-Soo Ahn
- Department of Dental Biomaterials Science and Dental Research Institute, School of Dentistry, Seoul National University, 101 Daehak-ro, Jongno-gu, Seoul 03080, Korea.
| | - Hyun-Suk Cha
- Division of Prosthodontics, Department of Dentistry, Asan Medical Center, College of Medicine, University of Ulsan, 88 Olympic-ro 43-gil, Songpa-gu, Seoul 05505, Korea.
| | - Joo-Hee Lee
- Division of Prosthodontics, Department of Dentistry, Asan Medical Center, College of Medicine, University of Ulsan, 88 Olympic-ro 43-gil, Songpa-gu, Seoul 05505, Korea.
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Belli R, Zorzin JI, Lohbauer U. Fracture Toughness Testing of Dental Restoratives: a Critical Evaluation. ACTA ACUST UNITED AC 2018. [DOI: 10.1007/s40496-018-0184-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Wendler M, Belli R, Valladares D, Petschelt A, Lohbauer U. Chairside CAD/CAM materials. Part 3: Cyclic fatigue parameters and lifetime predictions. Dent Mater 2018; 34:910-921. [DOI: 10.1016/j.dental.2018.03.024] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Revised: 03/13/2018] [Accepted: 03/23/2018] [Indexed: 10/17/2022]
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Kirsten M, Matta RE, Belli R, Lohbauer U, Wichmann M, Petschelt A, Zorzin J. Hygroscopic expansion of self-adhesive resin cements and the integrity of all-ceramic crowns. Dent Mater 2018; 34:1102-1111. [PMID: 29709240 DOI: 10.1016/j.dental.2018.04.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Revised: 04/09/2018] [Accepted: 04/15/2018] [Indexed: 11/30/2022]
Abstract
OBJECTIVE Low pH neutralization and subsequent remnant hydrophilicity can lead to hygroscopic expansion of self-adhesive resin cements (SARCs) after water storage. The aim of this in vitro study was to investigate the effects of hygroscopic expansion of SARCs, used as luting and partial core build-up material, on integrity and cement gap thickness increase of all-ceramic CAD/CAM crowns. METHODS Human third molars (n=48) were prepared and anatomical all-ceramic CAD/CAM crowns were manufactured (VITABLOCS Mark II, VITA Zahnfabrik). Crowns internal surfaces were HF etched and silanized. The prepared teeth with their respective crowns were divided into 6 groups (n=8). In groups 1, 3 and 5 the coronal dentin was removed to simulate a partial core build-up. Groups 1 and 2 were luted with iCEM (Heraeus Kulzer), 3 and 4 with RelyX Unicem 2 Automix (3M), 5 and 6 with Variolink Esthetic DC (Ivoclar Vivadent). All specimens were dual cured and stored in distilled water at 37°C. Crown integrity was controlled at baseline and in regular intervals until 180 days. Cement gap thickness was measured using an optical 3D scanner (ATOS Triple scan, GOM) at baseline and after 180 days. Crown integrity was statistically analysed using Kaplan-Meier survival analysis and cement gap thickness increase using two-way ANOVA (α=0.05). RESULTS After 180 days storage, crack formation was observed in all specimens of group 1 (mean survival time of 85.5 days), in one specimen of group 2 and in two specimens of group 4. Two-way ANOVA analysis revealed a statistically significant interaction between material type and build-up on cement gap size increase for iCEM. SIGNIFICANCE Within the limits of this study, the application of SARCs with low pH neutralization as partial build-up material under CAD/CAM crowns is not recommended for clinical use.
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Affiliation(s)
- Magdalena Kirsten
- Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Dental Clinic 1 - Operative Dentistry and Periodontology, Research Laboratory for Dental Biomaterials, Glückstrasse 11, D-91054 Erlangen, Germany
| | - Ragai Edward Matta
- Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Dental Clinic 2 - Department of Prosthodontics, Glückstrasse 11, D-91054 Erlangen, Germany
| | - Renan Belli
- Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Dental Clinic 1 - Operative Dentistry and Periodontology, Research Laboratory for Dental Biomaterials, Glückstrasse 11, D-91054 Erlangen, Germany
| | - Ulrich Lohbauer
- Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Dental Clinic 1 - Operative Dentistry and Periodontology, Research Laboratory for Dental Biomaterials, Glückstrasse 11, D-91054 Erlangen, Germany
| | - Manfred Wichmann
- Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Dental Clinic 2 - Department of Prosthodontics, Glückstrasse 11, D-91054 Erlangen, Germany
| | - Anselm Petschelt
- Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Dental Clinic 1 - Operative Dentistry and Periodontology, Research Laboratory for Dental Biomaterials, Glückstrasse 11, D-91054 Erlangen, Germany
| | - José Zorzin
- Friedrich-Alexander Universität Erlangen-Nürnberg (FAU), Dental Clinic 1 - Operative Dentistry and Periodontology, Research Laboratory for Dental Biomaterials, Glückstrasse 11, D-91054 Erlangen, Germany.
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