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Cheng YL, Zhong BJ, Su C, Lu ZC, Yu H. Enhanced tooth bleaching with a hydrogen peroxide/titanium dioxide gel. BMC Oral Health 2024; 24:923. [PMID: 39123150 PMCID: PMC11316293 DOI: 10.1186/s12903-024-04691-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2024] [Accepted: 07/30/2024] [Indexed: 08/12/2024] Open
Abstract
BACKGROUND This study aimed to explore the effects of the titanium dioxide (TiO2) concentration and particle size in hydrogen peroxide (HP) on tooth bleaching effectiveness and enamel surface properties. METHODS TiO2 at different concentrations and particle sizes was incorporated into 40% HP gel to form an HP/TiO2 gel. The specimens were randomly divided into 8 groups: C1P20: HP + 1% TiO2 (20 nm); C3P20: HP + 3% TiO2 (20 nm); C5P20: HP + 5% TiO2 (20 nm); C1P100: HP + 1% TiO2 (100 nm); C3P100: HP + 3% TiO2 (100 nm); C5P100: HP + 5% TiO2 (100 nm); C0: HP with LED; and C0-woL: HP without LED. Bleaching was conducted over 2 sessions, each lasting 40 min with a 7-day interval. The color differences (ΔE00), whiteness index for dentistry (WID), surface microhardness, roughness, microstructure, and composition were assessed. RESULTS The concentration and particle size of TiO2 significantly affected ΔE00 and ΔWID values, with the C1P100 group showing the greatest ΔE00 values and C1P100, C3P100, and C5P100 groups showing the greatest ΔWID values (p < 0.05). No significant changes were observed in surface microhardness, roughness, microstructure or composition (p > 0.05). CONCLUSIONS Incorporating 1% TiO2 with a particle size of 100 nm into HP constitutes an effective bleaching strategy to achieve desirable outcomes.
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Affiliation(s)
- Yi-Ling Cheng
- Fujian Key Laboratory of Oral Diseases & Fujian Provincial Engineering Research Center of Oral Biomaterial & Stomatological Key Laboratory of Fujian College and University, School and Hospital of Stomatology, Fujian Medical University, Fuzhou, China
- Department of Prosthodontics & Research Center of Dental Esthetics and Biomechanics, Fujian Medical University, Fuzhou, China
| | - Bing-Jie Zhong
- Fujian Key Laboratory of Oral Diseases & Fujian Provincial Engineering Research Center of Oral Biomaterial & Stomatological Key Laboratory of Fujian College and University, School and Hospital of Stomatology, Fujian Medical University, Fuzhou, China
| | - Chen Su
- Fujian Key Laboratory of Oral Diseases & Fujian Provincial Engineering Research Center of Oral Biomaterial & Stomatological Key Laboratory of Fujian College and University, School and Hospital of Stomatology, Fujian Medical University, Fuzhou, China
| | - Zhi-Cen Lu
- Fujian Key Laboratory of Oral Diseases & Fujian Provincial Engineering Research Center of Oral Biomaterial & Stomatological Key Laboratory of Fujian College and University, School and Hospital of Stomatology, Fujian Medical University, Fuzhou, China
- Department of Prosthodontics & Research Center of Dental Esthetics and Biomechanics, Fujian Medical University, Fuzhou, China
| | - Hao Yu
- Fujian Key Laboratory of Oral Diseases & Fujian Provincial Engineering Research Center of Oral Biomaterial & Stomatological Key Laboratory of Fujian College and University, School and Hospital of Stomatology, Fujian Medical University, Fuzhou, China.
- Department of Prosthodontics & Research Center of Dental Esthetics and Biomechanics, Fujian Medical University, Fuzhou, China.
- Department of Applied Prosthodontics, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan.
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Rizk A, Abdou A, Ashraf R, Omar S. Effect of multiple firings on optical and mechanical properties of Virgilite-containing lithium disilicate glass-ceramic of varying thickness. Clin Oral Investig 2024; 28:370. [PMID: 38869624 PMCID: PMC11176229 DOI: 10.1007/s00784-024-05746-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Accepted: 05/24/2024] [Indexed: 06/14/2024]
Abstract
OBJECTIVES To investigate the effect of multiple firings on color, translucency, and biaxial flexure strength of Virgilite-containing (Li0.5Al0.5Si2.5O6) lithium disilicate glass ceramics of varying thickness. MATERIALS AND METHODS Sixty discs were prepared from Virgilite-containing lithium disilicate blocks. Discs were divided according to thickness (n = 30) into T0.5 (0.5 mm) and T1.0 (1.0 mm). Each thickness was divided according to the number of firing cycles (n = 10); F1 (Control group): 1 firing cycle; F3: 3 firing cycles, and F5: 5 firing cycles. The discs were tested for color change (ΔE00) and translucency (TP00) using a spectrophotometer. Then, all samples were subjected to biaxial flexure strength testing using a universal testing machine. Data were collected and statistically analyzed (α = 0.5). For chemical analysis, six additional T0.5 discs (2 for each firing cycle) were prepared; for each firing cycle one disc was subjected to X-ray diffraction analysis (XRD) and another disc was subjected to Energy dispersive X-ray spectroscopy (EDX) and Scanning electron microscope (SEM). RESULTS Repeated firing significantly reduced the translucency of F3 and F5 compared to F1 in T0.5 (p < 0.001), while for T1.0 only F5 showed a significant decrease in TP00 (p < 0.001). For ΔE00, a significant increase was recorded with repeated firings (p < 0.05) while a significant decrease resulted in the biaxial flexure strength regardless of thickness. CONCLUSIONS Repeated firings had a negative effect on both the optical and mechanical properties of the Virgilite-containing lithium disilicate glass ceramics. CLINICAL RELEVANCE Repeated firings should be avoided with Virgilite-containing lithium disilicate ceramics to decrease fracture liability and preserve restoration esthetics.
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Affiliation(s)
- Amr Rizk
- Department of Prosthetic Dentistry, Fixed Prosthodontics Division, Faculty of Dentistry, King Salman International University, South Sinai, Egypt.
| | - Ahmed Abdou
- Department of Restorative Dentistry, Faculty of Dentistry, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Reem Ashraf
- Department of Prosthetic Dentistry, Dental Biomaterials Division, Faculty of Dentistry, King Salman International University, South Sinai, Egypt
| | - Sarah Omar
- Department of Prosthodontics, Faculty of Oral and Dental Medicine, Badr University in Cairo, Cairo, Egypt
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Calixto ET, Kelmer VF, Komegae GH, Pacheco RR, Pini N, Sundfeld D. Influence of Varied Silane Commercial Brands and Adhesive Application on Bond Strength and Stability to Lithium Disilicate Glass Ceramic. Oper Dent 2024; 49:325-335. [PMID: 38632867 DOI: 10.2341/23-124-l] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/05/2023] [Indexed: 04/19/2024]
Abstract
OBJECTIVES This study aimed to evaluate the impact of various commercial silane brands with varied chemical compositions with or without the application of an adhesive layer on the microshear bond strength and durability of a resin luting agent to lithium disilicate glass ceramic. METHODS AND MATERIALS Lithium disilicate glass ceramic discs (EMX, IPS e.max Press, Ivoclar Vivadent) measuring 10 mm in diameter and 3 mm in thickness were fabricated (n=240). Surfaces were etched using 5% hydrofluoric acid and randomly assigned to 10 groups based on the commercial brand of silane used (n=24): [RP] RelyX Ceramic Primer (3M ESPE); [PS] Prosil (FGM); [SA] Silano (Angelus); [SM] Silano (Maquira); [SU] Silane (Ultradent); [GL] GLUMA Ceramic Primer (Kulzer); [CB] Ceramic Bond (VOCO); [MB] Monobond N (Ivoclar Vivadent); [CP] Clearfil Ceramic Primer (Kuraray); and [DE] 2-step silane (Dentsply Sirona). Half of the EMXs (n=12) received a thin adhesive layer (+) after the silane and prior to resin luting agent, while the other half (n=12) did not receive an adhesive layer (-). For the microshear bond strength test (μSBS), four light-cured resin luting agent cylinders (1 mm in diameter) were created on each EMX surface. Half of these specimens were tested after 24 hours, while the other half were stored in deionized water for 6 months. The μSBS test was conducted using a universal testing machine (DL 500, EMIC) at a crosshead speed of 1 mm/min until failure. The obtained data underwent statistical analysis using analysis of variance (ANOVA) and the Tukey test (α=0.05). RESULTS There was significant influence of the silane commercial brand on bond strength. Notably, "universal primers" yielded lower bond strength results compared to "pure" silane solutions. Water storage had a detrimental effect on microshear bond strength for certain silane commercial brands. Additionally, the application of an adhesive layer negatively impacted bond strength results for all silanes. CONCLUSIONS This study confirms the importance of both silane commercial brand and chemical composition in relation to bond strength of resin luting agents to lithium disilicate glass ceramic. Furthermore, the application of an adhesive layer may have an adverse effect on bond stability over time.
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Affiliation(s)
- E T Calixto
- Emerson Tavares Calixto, DDS, MSc student, Ingá University Center, Uningá, Maningá, PR, Brazil
| | - V F Kelmer
- Vinicius Fernandez Kelmer, DDS student, Ingá University Center, Uningá, Maningá, PR, Brazil
| | - G H Komegae
- Gabriely Hikari Komegae, DDS, MSc student, Ingá University Center, Uningá, Maningá, PR, Brazil
| | - R R Pacheco
- Rafael Rocha Pacheco, DDS, MSc, PhD, associate professor and section director of Dental Materials, Department of Restorative Sciences, The Dental College of Georgia at Augusta University, Augusta, GA, USA
| | - Nip Pini
- Nubia Inocencya Pavesi Pini, DDS, MSc, PhD, adjunct professor, School of Dentistry, Department of Restorative Dentistry and Prosthodontics, Ingá University Center, Uningá, Maningá, PR, Brazil
| | - D Sundfeld
- *Daniel Sundfeld, DDS, MSc, PhD, adjunct professor, Department of Restorative Dentistry and Prosthodontics, Ingá University Center, Uningá, Maningá, PR, Brazil
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Chai H, Russ J, Vardhaman S, Lim CH, Zhang Y. A Bilayer Method for Measuring Toughness and Strength of Dental Ceramics. J Dent Res 2024; 103:419-426. [PMID: 38410925 DOI: 10.1177/00220345231225445] [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: 02/28/2024] Open
Abstract
The ever-increasing usage of ceramic materials in restorative dentistry necessitates a simple and effective method to evaluate flexural strength σF and fracture toughness KC. We propose a novel method to determine these quantities using a bilayer specimen composed of a brittle plate adhesively bonded onto a transparent polycarbonate substrate. When this bilayer structure is placed under spherical indentation, tunneling radial cracks initiate and propagate in the lower surface of the brittle layer. The failure analysis is based on previous theoretical relationships, which correlate σF with the indentation force P and layer thickness d, and KC with P and mean length of radial cracks. This work examines the accuracy and limitations of this approach using a wide range of contemporary dental ceramic materials. The effect of layer thickness, indenter radius, load level, and length and number of radial cracks are carefully examined. The accuracy of the predicted σF and KC is similar to those obtained with other concurrent test methods, such as biaxial flexure and 3-point bending (σF), and bending specimens with crack-initiation flaws (KC). The benefits of the present approach include treatment for small and thin plates, elimination of the need to introduce a precrack, and avoidance of dealing with local material nonlinearity effects for the KC measurements. Finally, the bilayer configuration resembles occlusal loading of a ceramic restoration (brittle layer) bonded to a posterior tooth (compliant substrate).
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Affiliation(s)
- H Chai
- School of Mechanical Engineering, Faculty of Engineering, Tel Aviv University, Tel Aviv, Israel
| | - J Russ
- School of Dental Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - S Vardhaman
- Department of Preventive and Restorative Sciences, University of Pennsylvania, School of Dental Medicine, Philadelphia, PA, USA
- College of Dental Medicine, Columbia University, New York, NY, USA
| | - C H Lim
- Department of Preventive and Restorative Sciences, University of Pennsylvania, School of Dental Medicine, Philadelphia, PA, USA
| | - Y Zhang
- Department of Preventive and Restorative Sciences, University of Pennsylvania, School of Dental Medicine, Philadelphia, PA, USA
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Diken Türksayar AA, Demirel M, Donmez MB. Optical properties, biaxial flexural strength, and reliability of new-generation lithium disilicate glass-ceramics after thermal cycling. J Prosthodont 2023; 32:815-820. [PMID: 36585789 DOI: 10.1111/jopr.13632] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Revised: 11/24/2022] [Accepted: 12/16/2022] [Indexed: 01/01/2023] Open
Abstract
PURPOSE To investigate the color stability, translucency, biaxial flexural strength (BFS), and reliability of nano-lithium disilicate and fully crystallized lithium disilicate after thermal cycling and to compare with those of a commonly used lithium disilicate. MATERIALS AND METHODS Three lithium disilicate glass-ceramics were used to prepare disk-shaped specimens (ø:12 mm, thickness: 1.2 mm) from A2 shaded HT blocks (Amber Mill, AM; Initial LiSi Block, IN; IPS e.max CAD, EX). AM and EX specimens were crystallized, and all specimens were polished with a polishing paste (Diamond Polish Mint). A spectrophotometer (CM-26d) was used to measure color coordinates before and after thermal cycling. BFS test was performed after thermal cycling. Color differences (ΔE00 ) and relative translucency parameter (RTP) values were calculated. One-way analysis of variance (ANOVA) (ΔE00 and BFS), two-way ANOVA followed by Tukey's HSD tests (RTP), and chi-square tests (Weibull modulus and characteristic strength) were used for the statistical analyses (α = 0.05). RESULTS No significant differences were observed among the ΔE00 values of tested materials (df = 2, F = 2.933, p = 0.070). RTP values were only affected by material type (p < 0.001) as AM had the highest RTP (p < 0.001), whereas IN and EX had similar values (p ≥ 0.165). BFS values varied among tested materials (df = 2, F = 21.341, p < 0.001). AM and EX had similar BFS values (p = 0.067) that were higher than that of IN (p ≤ 0.001). Weibull moduli of the materials were similar (p = 0.305), whereas EX had the highest and IN had the lowest characteristic strength values (p < 0.001) CONCLUSIONS: Although nano-lithium disilicate had the highest translucency, all materials had imperceptible color and translucency changes after thermal cycling when reported threshold values were considered. Newly introduced lithium disilicate glass-ceramics had adequate flexural strength as compared to the precursor material.
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Affiliation(s)
- Almira Ada Diken Türksayar
- Department of Prosthodontics, Faculty of Dentistry, Biruni University, İstanbul, Turkey
- ADMiRE Research Center-Additive Manufacturing, Intelligent Robotics, Sensors and Engineering, School of Engineering and IT, Carinthia University of Applied Sciences, Villach, Austria
| | - Münir Demirel
- Oral and Dental Health, Vocational School, Biruni University, İstanbul, Turkey
| | - Mustafa Borga Donmez
- Department of Prosthodontics, Faculty of Dentistry, Istinye University, İstanbul, Turkey
- Department of Reconstructive Dentistry and Gerodontology, School of Dental Medicine, University of Bern, Bern, Switzerland
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Vichi A, Zhao Z, Mutahar M, Paolone G, Louca C. Translucency of Lithium-Based Silicate Glass-Ceramics Blocks for CAD/CAM Procedures: A Narrative Review. MATERIALS (BASEL, SWITZERLAND) 2023; 16:6441. [PMID: 37834578 PMCID: PMC10573117 DOI: 10.3390/ma16196441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Revised: 09/20/2023] [Accepted: 09/21/2023] [Indexed: 10/15/2023]
Abstract
Amid chairside CAD/CAM materials, the use of lithium-based silicate glass-ceramics (LSGC) has been steadily increasing. This review aims to report on the translucency of these materials and the variables used to measure it. An electronic search was performed within the PubMed database within the period between 2 June 2011 and 11 September 2022. English-language papers investigating the translucency of IPS e.max CAD, Celtra Duo, Suprinity PC, Initial LiSi Block, Amber Mill, N!ce, and CEREC Tessera LSGC CAD/blocks were included in the search strategy. After an initial retrieval of 160 papers, the application of exclusion criteria, and the screening of abstracts and then of full texts, 33 papers were included in the study. The retrieved materials, with different degrees of translucency (LT, HT), were IPS e.max CAD (n = 33), Suprinity PC (n = 8), and Celtra Duo (n = 1). Concerning the examined colors, the most used was A2 (n = 20), followed by A1 (n = 8) and A3 (n = 2). The translucency parameter (TP) was the most used method (n = 30) with respect to the contrast ratio (CR) (n = 11) to assess translucency. Five papers measured both. Several specimens' thicknesses (0.5-4 mm) were investigated, with 1 mm (n = 23) being the most frequently analyzed. While a general tendency could be identified, conflicting results among different papers were reported.
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Affiliation(s)
- Alessandro Vichi
- Dental Academy, University of Portsmouth, Portsmouth PO1 2QG, UK (C.L.)
| | - Zejiao Zhao
- Dental Academy, University of Portsmouth, Portsmouth PO1 2QG, UK (C.L.)
| | - Mahdi Mutahar
- Dental Academy, University of Portsmouth, Portsmouth PO1 2QG, UK (C.L.)
| | - Gaetano Paolone
- Dental School, IRCCS San Raffaele Hospital, Vita-Salute University, 20132 Milan, Italy
| | - Chris Louca
- Dental Academy, University of Portsmouth, Portsmouth PO1 2QG, UK (C.L.)
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Munoz A, Zhao Z, Paolone G, Louca C, Vichi A. Flexural Strength of CAD/CAM Lithium-Based Silicate Glass-Ceramics: A Narrative Review. MATERIALS (BASEL, SWITZERLAND) 2023; 16:4398. [PMID: 37374581 DOI: 10.3390/ma16124398] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2023] [Revised: 06/01/2023] [Accepted: 06/09/2023] [Indexed: 06/29/2023]
Abstract
Amongst chairside CAD/CAM materials, the use of lithium-based silicate glass-ceramics (LSGC) for indirect restorations has recently been increasing. Flexural strength is one of the most important parameters to consider in the clinical selection of materials. The aim of this paper is to review the flexural strength of LSGC and the methods used to measure it. METHODS The electronic search was completed within PubMed database from 2 June 2011 to 2 June 2022. English-language papers investigating the flexural strength of IPS e.max CAD, Celtra Duo, Suprinity PC, and n!ce CAD/CAM blocks were included in the search strategy. RESULTS From 211 potential articles, a total of 26 were identified for a comprehensive analysis. Categorization per material was carried out as follows: IPS e.max CAD (n = 27), Suprinity PC (n = 8), Celtra Duo (n = 6), and n!ce (n = 1). The three-point bending test (3-PBT) was used in 18 articles, followed by biaxial flexural test (BFT) in 10 articles, with one of these using the four-point bending test (4-PBT) as well. The most common specimen dimension was 14 × 4 × 1.2 mm (plates) for the 3-PBT and 12 × 1.2 mm (discs) for BFT. The flexural strength values for LSGC materials varied widely between the studies. SIGNIFICANCE As new LSGC materials are launched on the market, clinicians need to be aware of their flexural strength differences, which could influence the clinical performance of restorations.
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Affiliation(s)
- Alvaro Munoz
- Faculty of Dentistry, University of Chile, Santiago 8380544, Chile
| | - Zejiao Zhao
- Dental Academy, University of Portsmouth, Portsmouth PO1 2QG, UK
| | - Gaetano Paolone
- Dental School, IRCCS San Raffaele Hospital, Vita-Salute University, 20132 Milan, Italy
| | - Chris Louca
- Dental Academy, University of Portsmouth, Portsmouth PO1 2QG, UK
| | - Alessandro Vichi
- Dental Academy, University of Portsmouth, Portsmouth PO1 2QG, UK
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PEREIRA RM, RIBAS RG, MONTANHEIRO TLDA, SCHATKOSKI VM, RODRIGUES KF, KITO LT, KOBO LK, CAMPOS TMB, BONFANTE EA, GIERTHMUEHLEN PC, SPITZNAGEL FA, THIM GP. An engineering perspective of ceramics applied in dental reconstructions. J Appl Oral Sci 2023; 31:e20220421. [PMID: 36820784 PMCID: PMC9972857 DOI: 10.1590/1678-7757-2022-0421] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Accepted: 01/04/2023] [Indexed: 02/22/2023] Open
Abstract
The demands for dental materials continue to grow, driven by the desire to reach a better performance than currently achieved by the available materials. In the dental restorative ceramic field, the structures evolved from the metal-ceramic systems to highly translucent multilayered zirconia, aiming not only for tailored mechanical properties but also for the aesthetics to mimic natural teeth. Ceramics are widely used in prosthetic dentistry due to their attractive clinical properties, including high strength, biocompatibility, chemical stability, and a good combination of optical properties. Metal-ceramics type has always been the golden standard of dental reconstruction. However, this system lacks aesthetic aspects. For this reason, efforts are made to develop materials that met both the mechanical features necessary for the safe performance of the restoration as well as the aesthetic aspects, aiming for a beautiful smile. In this field, glass and high-strength core ceramics have been highly investigated for applications in dental restoration due to their excellent combination of mechanical properties and translucency. However, since these are recent materials when compared with the metal-ceramic system, many studies are still required to guarantee the quality and longevity of these systems. Therefore, a background on available dental materials properties is a starting point to provoke a discussion on the development of potential alternatives to rehabilitate lost hard and soft tissue structures with ceramic-based tooth and implant-supported reconstructions. This review aims to bring the most recent materials research of the two major categories of ceramic restorations: ceramic-metal system and all-ceramic restorations. The practical aspects are herein presented regarding the evolution and development of materials, technologies applications, strength, color, and aesthetics. A trend was observed to use high-strength core ceramics type due to their ability to be manufactured by CAD/CAM technology. In addition, the impacts of COVID-19 on the market of dental restorative ceramics are presented.
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Affiliation(s)
- Raíssa Monteiro PEREIRA
- Instituto Tecnológico de AeronáuticaLaboratório de Plasma e ProcessosSão José dos CamposBrasilInstituto Tecnológico de Aeronáutica (ITA), Laboratório de Plasma e Processos (LPP), São José dos Campos, Brasil
| | - Renata Guimarães RIBAS
- Instituto Tecnológico de AeronáuticaLaboratório de Plasma e ProcessosSão José dos CamposBrasilInstituto Tecnológico de Aeronáutica (ITA), Laboratório de Plasma e Processos (LPP), São José dos Campos, Brasil
| | - Thaís Larissa do Amaral MONTANHEIRO
- Instituto Tecnológico de AeronáuticaLaboratório de Plasma e ProcessosSão José dos CamposBrasilInstituto Tecnológico de Aeronáutica (ITA), Laboratório de Plasma e Processos (LPP), São José dos Campos, Brasil
| | - Vanessa Modelski SCHATKOSKI
- Instituto Tecnológico de AeronáuticaLaboratório de Plasma e ProcessosSão José dos CamposBrasilInstituto Tecnológico de Aeronáutica (ITA), Laboratório de Plasma e Processos (LPP), São José dos Campos, Brasil
| | - Karla Faquine RODRIGUES
- Instituto Tecnológico de AeronáuticaLaboratório de Plasma e ProcessosSão José dos CamposBrasilInstituto Tecnológico de Aeronáutica (ITA), Laboratório de Plasma e Processos (LPP), São José dos Campos, Brasil
| | - Letícia Terumi KITO
- Instituto Tecnológico de AeronáuticaLaboratório de Plasma e ProcessosSão José dos CamposBrasilInstituto Tecnológico de Aeronáutica (ITA), Laboratório de Plasma e Processos (LPP), São José dos Campos, Brasil
| | - Lucas Kazunori KOBO
- Instituto Tecnológico de AeronáuticaLaboratório de Plasma e ProcessosSão José dos CamposBrasilInstituto Tecnológico de Aeronáutica (ITA), Laboratório de Plasma e Processos (LPP), São José dos Campos, Brasil
| | - Tiago Moreira Bastos CAMPOS
- Instituto Tecnológico de AeronáuticaLaboratório de Plasma e ProcessosSão José dos CamposBrasilInstituto Tecnológico de Aeronáutica (ITA), Laboratório de Plasma e Processos (LPP), São José dos Campos, Brasil
| | - Estevam Augusto BONFANTE
- Universidade de São PauloFaculdade de Odontologia de BauruDepartamento de Prótese e PeriodontiaBauruSPBrasilUniversidade de São Paulo, Faculdade de Odontologia de Bauru, Departamento de Prótese e Periodontia, Bauru, SP, Brasil.
| | - Petra Christine GIERTHMUEHLEN
- Heinrich-Heine-UniversityMedical FacultyUniversity Hospital DüsseldorfDüsseldorfGermanyHeinrich-Heine-University, Medical Faculty and University Hospital Düsseldorf, Düsseldorf, Department of Prosthodontics, Germany.
| | - Frank Akito SPITZNAGEL
- Heinrich-Heine-UniversityMedical FacultyUniversity Hospital DüsseldorfDüsseldorfGermanyHeinrich-Heine-University, Medical Faculty and University Hospital Düsseldorf, Düsseldorf, Department of Prosthodontics, Germany.
| | - Gilmar Patrocínio THIM
- Instituto Tecnológico de AeronáuticaLaboratório de Plasma e ProcessosSão José dos CamposBrasilInstituto Tecnológico de Aeronáutica (ITA), Laboratório de Plasma e Processos (LPP), São José dos Campos, Brasil
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Osman MLM, Lim TW, Chang HC, Ab Ghani AR, Tsoi JKH, Ab Ghani SM. Structural Integrity of Anterior Ceramic Resin-Bonded Fixed Partial Denture: A Finite Element Analysis Study. J Funct Biomater 2023; 14:jfb14020108. [PMID: 36826907 PMCID: PMC9962904 DOI: 10.3390/jfb14020108] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Revised: 02/06/2023] [Accepted: 02/09/2023] [Indexed: 02/17/2023] Open
Abstract
This study was conducted as a means to evaluate the stress distribution patterns of anterior ceramic resin-bonded fixed partial dentures derived from different materials and numerous connector designs that had various loading conditions imposed onto them through the utilization of the finite element method. A finite element model was established on the basis of the cone beam computed tomography image of a cantilevered resin-bonded fixed partial denture with a central incisor as an abutment and a lateral incisor as a pontic. Sixteen finite element models representing different conditions were simulated with lithium disilicate and zirconia. Connector height, width, and shape were set as the geometric parameters. Static loads of 100 N, 150 N, and 200 N were applied at 45 degrees to the pontic. The maximum equivalent stress values obtained for all finite element models were compared with the ultimate strengths of their materials. Higher load exhibited greater maximum equivalent stress in both materials, regardless of the connector width and shape. Loadings of 200 N and 150 N that were correspondingly simulated on lithium disilicate prostheses of all shapes and dimensions resulted in connector fractures. On the contrary, loadings of 200 N, 150 N, and 100 N with rectangular-shaped connectors correspondingly simulated on zirconia were able to withstand the loads. However, two of the trapezoidal-shaped zirconia connectors were unable to withstand the loads and resulted in fractures. It can be deduced that material type, shape, and connector dimensions concurrently influenced the integrity of the bridge.
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Affiliation(s)
- Mas Linda Mohd Osman
- Centre of Restorative Dentistry Studies, Faculty of Dentistry, Universiti Teknologi MARA, Sungai Buloh 47000, Selangor, Malaysia
| | - Tong Wah Lim
- Division of Restorative Dental Sciences, Faculty of Dentistry, The University of Hong Kong, Hong Kong SAR, China
| | - Hung-Chih Chang
- Department of Biomedical Engineering, Hungkuang University, Taichung City 433304, Taiwan
| | - Amir Radzi Ab Ghani
- College of Engineering, Universiti Teknologi MARA, Shah Alam 40450, Selangor, Malaysia
| | - James Kit Hon Tsoi
- Division of Applied Oral Sciences and Community Dental Care, Faculty of Dentistry, The University of Hong Kong, Hong Kong SAR, China
| | - Siti Mariam Ab Ghani
- Centre of Restorative Dentistry Studies, Faculty of Dentistry, Universiti Teknologi MARA, Sungai Buloh 47000, Selangor, Malaysia
- Correspondence: ; Tel.: +86-603-61266611
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Yamaguchi S, Li H, Imazato S. Materials informatics for developing new restorative dental materials: A narrative review. FRONTIERS IN DENTAL MEDICINE 2023. [DOI: 10.3389/fdmed.2023.1123976] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Materials informatics involves the application of computational methodologies to process and interpret scientific and engineering data concerning materials. Although this concept has been well established in the fields of biology, drug discovery, and classic materials research, its application in the field of dental materials is still in its infancy. This narrative review comprehensively summarizes the advantages, limitations, and future perspectives of materials informatics from 2003 to 2022 for exploring the optimum compositions in developing new materials using artificial intelligence. The findings indicate that materials informatics, which is a recognized and established concept in the materials science field, will accelerate the process of restorative materials development and contribute to produce new insights into dental materials research.
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Flexural strengths, failure load, and hardness of glass-ceramics for dental applications. J Prosthet Dent 2022; 128:512.e1-512.e9. [PMID: 35989200 DOI: 10.1016/j.prosdent.2022.05.023] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Revised: 05/29/2022] [Accepted: 05/31/2022] [Indexed: 11/23/2022]
Abstract
STATEMENT OF PROBLEM Glass-ceramics are often selected for use in dental restorations based upon advertised flexural strengths obtained from standardized tests on prefabricated specimens (bars and disks); these may not accurately reflect their performance in dental applications. PURPOSE The purpose of this in vitro study was to determine and compare 4-point flexural strength, biaxial flexural strength, hardness, and crown failure loads for 3 commercially available glass-ceramics. MATERIAL AND METHODS Specimens were pressed and prepared from 3 brands of glass-ceramics: Celtra (CEL), IPS e.max (EMA), and Lisi (LIS). Rectangular bars, circular disks, and fully contoured crowns were created (n=15 specimens per glass-ceramic, 45 specimens per geometry, totaling 135 specimens). Disks were tested for biaxial flexural strength by using a piston-on-3-ball (POB) test, while bars were tested for 4-point flexural strength by using 4-point bending (4PB) and Vickers hardness (VH) tests. Crown failure loads were assessed in "crunch-the-crown" (CTC) tests. The results were analyzed by using general linear modeling, the Pearson correlation coefficient, and Weibull analysis. RESULTS The general linear modeling revealed significant differences (P<.05) in the failure load for crown specimens (EMA>LIS>CEL), the 4-point flexural strength (EMA>LIS>CEL), and the biaxial flexural strength (EMA>LIS=CEL). The disk specimens had higher flexural strengths than the bar specimens for CEL and EMA materials. LIS had a higher Weibull modulus than EMA and CEL for bar and crown specimens. CEL had a higher Weibull modulus than LIS and EMA for disk specimens. There was no correlation among the VH (R2=0.86 and P=.24), biaxial flexural strength (R2=0.84 and P=.26), and crown failure load. However, there was a high correlation between the failure load (crown specimens) and 4-point flexural strength (bar specimens) (R2=0.99 and P=.03). CONCLUSIONS The 4-point flexural strength correlated significantly with crown failure load.
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Phark JH, Duarte S. Microstructural considerations for novel lithium disilicate glass ceramics: A review. J ESTHET RESTOR DENT 2022; 34:92-103. [PMID: 34995008 DOI: 10.1111/jerd.12864] [Citation(s) in RCA: 33] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Revised: 12/17/2021] [Accepted: 12/20/2021] [Indexed: 11/29/2022]
Abstract
OBJECTIVE To review the ultrastructural characteristics of novel lithium disilicate based glass ceramics (LDC), how their manufacturing process influences their structure and their clinical use. OVERVIEW Lithium disilicate based glass ceramic has been successfully used for indirect restorations ranging from partial tooth coverage up to tooth replacement for over 20 years. It combines esthetic and mechanical properties, unlike any other indirect material which makes it an indispensable part of esthetic and restorative dentistry. Recently, novel LDCs have been introduced to the market. Parameters for their use and their microstructure are still not been widely known. This article will review these materials and highlight with high-resolution scanning electron microscopic images their structural aspects and their resulting clinical relevance. CONCLUSION Restorations made from LDCs are reliable and can be predictably used only when proper guidelines and protocols during manufacturing and clinical use are followed. For novel LDCs manufacturing and long-term bonding protocols still must be established. Moreover, novel LDCs machinable blocks should be crystallized or heat-treated after milling for superior performance. CLINICAL SIGNIFICANCE With more and newer etchable LDC materials entering the market, clinicians and technicians need to be aware of the differences in manufacturing and the resulting microstructure to ensure a successful treatment outcome that will last.
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Affiliation(s)
- Jin-Ho Phark
- Department of Operative Dentistry, Herman Ostrow School of Dentistry, University of Southern California, Los Angeles, California, USA
| | - Sillas Duarte
- Advanced Operative and Adhesive Dentistry, Division of Restorative Sciences, Herman Ostrow School of Dentistry, University of Southern California, Los Angeles, California, USA
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Chu H, Chen L, Lu D, Wang Y, Zheng X. Ultrasonic pretreatment of spodumene with different size fractions and its influence on flotation. ULTRASONICS SONOCHEMISTRY 2022; 82:105889. [PMID: 34979458 PMCID: PMC8799599 DOI: 10.1016/j.ultsonch.2021.105889] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 12/19/2021] [Accepted: 12/21/2021] [Indexed: 05/11/2023]
Abstract
The potential of ultrasonic pretreatment enhancing selective surface dissolution to improve the floatability of spodumene with different size fractions was verified and investigated. For coarse particles of -0.15 + 0.0385 mm, compared with traditional pretreatment methods, ultrasonic pretreatment could optimize the physicochemical properties of the surface, markedly increased the amount of NaOL adsorbed on the mineral surface, and improved the floatability of the spodumene. For fine particles of -0.0385 mm, both pretreatment methods (Ultrasonic and Traditional) could greatly increase the flotation recovery, but ultrasonic pretreatment had no obvious advantage compared with traditional method. ICP combined with XPS analysis were conducted to investigate the dissolution mechanism of spodumene surface in different pretreatment system. Si species on the surface of coarse particles were easily dissolved into the solution under the effect of ultrasound, which increases the relative content of Al and Li species on the surface. This was conducive to the adsorption of the collectors on the surface. However, the selective dissolution of the fine particle surface was weakened by excessive energy intake in the ultrasonic system, which neutralized the advantage brought by the large amount of dissolution, making the results obtained by the two preprocessing methods the same.
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Affiliation(s)
- Haoran Chu
- School of Minerals Processing and Bioengineering, Central South University, Changsha, China
| | - Lanlan Chen
- School of Minerals Processing and Bioengineering, Central South University, Changsha, China
| | - Dongfang Lu
- School of Minerals Processing and Bioengineering, Central South University, Changsha, China.
| | - Yuhua Wang
- School of Minerals Processing and Bioengineering, Central South University, Changsha, China
| | - Xiayu Zheng
- School of Minerals Processing and Bioengineering, Central South University, Changsha, China
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Translucency and flexural strength of translucent zirconia ceramics. J Prosthet Dent 2021; 129:644-649. [PMID: 34303523 DOI: 10.1016/j.prosdent.2021.06.019] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Revised: 06/10/2021] [Accepted: 06/11/2021] [Indexed: 11/21/2022]
Abstract
STATEMENT OF PROBLEM Translucent zirconias have been developed with better esthetics than high-strength zirconias by reducing opacity. However, studies on their translucency and strength are sparse. PURPOSE The purpose of this in vitro study was to compare the relationship between translucency and biaxial flexural strength of recently developed high-translucency zirconia, high-strength zirconia, and lithium disilicate ceramics. MATERIAL AND METHODS Disks (n=12) were fabricated for 5 ceramic materials: high-strength zirconia (BruxZir 16 shaded), translucent zirconia (BruxZir Anterior shaded, Katana UTML, Katana STML), and lithium disilicate (IPS e.max, Press HT, and LT). A standard tessellation language (STL) file was designed, and the specimen milled, finished, and glazed according to manufacturer's instructions for each material. The translucency parameter was calculated against black and white backgrounds and white and stump shade with ND4 background by using a spectrophotometer. Biaxial flexural strength was calculated by using the 3-ball test. The load was applied at a crosshead speed of 0.5 mm/min with a 49-N load cell until failure occurred. Translucency parameter and biaxial flexural strength data were analyzed with 1-way analysis of variance (ANOVA). A Tukey honest significant difference multiple comparison test was used to determine significant differences (α=.05). RESULTS The IPS e.max HT was more translucent against both backgrounds (32.85 for black/white and 15.34 for white/stump), while BruxZir 16 was the least translucent (19.78 for B/W and 8.83 for W/S). All groups tested differed in translucency (P<.001) except for BruxZir Anterior and Katana STML, which were not significantly different (P=.052). For biaxial flexural strength, BruxZir 16 had the highest strength (995.44 MPa) and e.max HT, the lowest (186.75 MPa). No significant differences were found between BruxZir anterior and Katana STML, Katana UTML and IPS e.max LT, or IPS e.max LT and IPS e.max HT (P>.05). Translucency parameter values using both backgrounds were strongly correlated (r=0.99). However, biaxial flexural strength values were inversely related to translucency parameter values when using black/white and white/stump shade but with high correlation (r=-0.777 and -0.756 respectively). CONCLUSIONS Lithium disilicate was the most translucent and yet the weakest material, whereas high-strength zirconia was the most opaque ceramic and the strongest. Katana UTML had the highest translucency but was weakest among translucent and high-strength zirconia materials. Overall, translucency was negatively correlated with biaxial flexural strength.
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Qiu Z, Wang Y. Multi-tip indenter tool scratch behavior of glass-ceramics. J Mech Behav Biomed Mater 2021; 121:104617. [PMID: 34091152 DOI: 10.1016/j.jmbbm.2021.104617] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 05/23/2021] [Accepted: 05/27/2021] [Indexed: 01/29/2023]
Abstract
To reduce the surface flaws and subsurface damages of glass-ceramics as clinical substitute and repair materials, it is necessary to clarify the material removal behaviors and crack propagation modes in the grinding process. In this paper, a multi-tip indenter tool was fabricated and assembled on a Nanomechanical testing system. The experiments of ramp load scratching with the single-tip/multi-tip indenter tools were conducted on glass-ceramics to compare the material removal behavior under different scratch methods. The surface morphology, subsurface cracks propagation, and the brittle-ductile transition region were observed and investigated. Based on the scratch experiments, the finite element simulation model was established to analyze the stress characteristics in the glass-ceramics. The result shows that in multi-tip scratches, as the depth of scratch increases, the growth of surface cracks mainly takes three forms. Compared with non-instant multi-scratch, instant multi-scratch makes the propagation path of lateral cracks closer to specimen surface, suppresses the propagation severity of lateral and median cracks, and increases the depth of brittle-ductile transition region. This paper's results provide a fundamental understanding of multiple abrasive grains instant interaction on the material removal mechanism, and help to improve the clinical performance of glass-ceramics as biomedical materials.
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Affiliation(s)
- Zhongjun Qiu
- State Key Laboratory of Precision Measuring Technology & Instruments, Tianjin University, Tianjin, 300072, China.
| | - Yuge Wang
- State Key Laboratory of Precision Measuring Technology & Instruments, Tianjin University, Tianjin, 300072, China
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Stawarczyk B, Mandl A, Liebermann A. Modern CAD/CAM silicate ceramics, their translucency level and impact of hydrothermal aging on translucency, Martens hardness, biaxial flexural strength and their reliability. J Mech Behav Biomed Mater 2021; 118:104456. [PMID: 33740686 DOI: 10.1016/j.jmbbm.2021.104456] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 03/05/2021] [Accepted: 03/08/2021] [Indexed: 10/21/2022]
Abstract
OBJECTIVES To investigate the impact of hydrothermal aging on Martens parameter (Martens hardness: HM/elastic indentation modulus: EIT) and biaxial flexural strength (BFS) of recently available CAD/CAM silicate ceramics. METHODS 220 specimens (diameter: 12 mm, thickness: 0.95 mm) were fabricated from six CAD/CAM ceramics in two translucency levels (LT/HT): (a) two lithium disilicate (Amber Mill, ABM; IPS e.max CAD, IEM), (b) one lithium metasilicate (Cetra Duo, CEL), (c) one lithium alumina silicate (n!ce, NIC), and (d) two leucite ceramics (Initial LRF Block, LRF; IPS Empress CAD, IPR). HM/EIT and BFS were measured initially and after hydrothermal aging (134 °C/0.2 MPa/100 h) in an autoclave. The Kolmogorov-Smirnov-test, t-test, one-way ANOVA with post-hoc Scheffé test, Kruskal-Wallis-test, Mann-Whitney-U-test with Bonferroni correction and Weibull statistics were performed (α = 0.05). RESULTS CEL and IEM showed the highest and the leucite ceramics the lowest Martens parameter. Within HT, ABM and NIC were in same initial HM value range with CEL and IEM. ABM and NIC showed lower initial EIT values than CEL and IEM, however higher than IPR. The lowest aged values were analyzed for ABM. After aging, Martens parameter decreased for LRF, ABM, and CEL. IEM showed the initial highest BFS, followed by ABM. NIC and LRF showed the lowest BFS. IEM and ABM presented the highest aged BFS. Hydrothermal aging increased BFS values for LRF (HT), IPR, CEL (HT), and NIC (HT) compared to the initial values. CAD/CAM leucite ceramics showed higher Weibull modul values compared to lithium silicate ceramics. SIGNIFICANCE The well-considered selection of ceramics in relation to the areas of indication has the highest influence on the long-term stability of restorations: CAD/CAM lithium disilicate ceramics presented the highest and leucite ceramics the lowest mechanical properties, whereas the reliability was better for leucite than for lithium silicate ceramics.
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Affiliation(s)
- Bogna Stawarczyk
- Department of Prosthetic Dentistry, LMU Munich, Munich, Germany.
| | - Alicia Mandl
- Department of Prosthetic Dentistry, LMU Munich, Munich, Germany
| | - Anja Liebermann
- Department of Prosthetic Dentistry, LMU Munich, Munich, Germany
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Flask JD, Thompson GA, Singh M, Berzins DW. Edge chipping of translucent zirconia. J Prosthet Dent 2021; 127:793-800. [PMID: 33581865 DOI: 10.1016/j.prosdent.2020.12.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 12/09/2020] [Accepted: 12/09/2020] [Indexed: 11/28/2022]
Abstract
STATEMENT OF PROBLEM More translucent dental zirconias have been developed by incorporating the cubic phase and reducing the tetragonal phase content that undergoes transformation toughening, leading to reduced mechanical properties. Whether the clinically relevant mechanical property of the edge chipping toughness of the material is also reduced is unclear. PURPOSE The purpose of this in vitro study was to evaluate the edge chipping toughness and translucency of translucent zirconia, 3mol% yttria-stabilized tetragonal zirconia polycrystal (3Y-TZP), and lithium disilicate. MATERIAL AND METHODS Two translucent zirconia products, Katana and Lava Esthetic; one 3Y-TZP, Lava Plus; and one lithium disilicate, IPS e.max Press were prepared and tested for phase composition via X-ray diffraction (XRD) (n=3), translucency via a spectrophotometer (n=20), and edge chipping via a universal testing machine with a custom-machined specimen holder and diamond indenter (n=20). The 3Y-TZP and lithium disilicate served as the optimal control materials for edge chipping and translucency, respectively. Translucency was compared with 1-way ANOVA and edge toughness with ANCOVA (α=.05). RESULTS The XRD showed the 3Y-TZP to be almost completely tetragonal phase compared with the 2 translucent zirconia products that were predominantly cubic. Katana UTML and IPS e.max Press had a statistically similar (P>.05) translucency that was significantly (P<.05) greater than that of Lava Esthetic and Lava Plus. The edge toughness of Katana UTML was 304 N/mm, IPS e.max Press was 354 N/mm, Lava Esthetic was 394 N/mm, and Lava Plus was 717 N/mm, with significance rankings of Katana UTM<IPS e.max Press=Lava Esthetic<Lava Plus. CONCLUSIONS Some translucent zirconias had translucency similar to that of lithium disilicate; however, as translucency increased with increased cubic content, edge toughness decreased.
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Affiliation(s)
- Joseph D Flask
- Graduate student of Dental Biomaterials, Department of General Dental Sciences, Marquette University School of Dentistry, Milwaukee, Wis.
| | - Geoffrey A Thompson
- Professor, Graduate Prosthodontics, Department of General Dental Sciences, Marquette University School of Dentistry, Milwaukee, Wis
| | - Maharaj Singh
- Research Assistant Professor, Biostatistics-Research and Graduate Studies, Marquette University School of Dentistry, Milwaukee, Wis
| | - David W Berzins
- Professor, Dental Biomaterials, Department of General Dental Sciences, Marquette University School of Dentistry, Milwaukee, Wis
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Ozdogan A, Ozdemir H. Effects of multiple firing processes on the mechanical properties of lithium disilicate glass-ceramics produced by two different production techniques. J Prosthet Dent 2020; 125:527.e1-527.e7. [PMID: 33243470 DOI: 10.1016/j.prosdent.2020.10.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2019] [Revised: 10/20/2020] [Accepted: 10/20/2020] [Indexed: 11/17/2022]
Abstract
STATEMENT OF PROBLEM Repeated firings cause materials to be exposed to additional heat treatments. The effect of these additional heat treatments on the mechanical properties of lithium disilicate glass-ceramics is not fully known. PURPOSE The purpose of this in vitro study was to determine the effects of repeated firing on the mechanical properties of lithium disilicate glass-ceramics produced by 2 different techniques, press and computer-aided design and computer-aided manufacturing (CAD-CAM). MATERIAL AND METHODS Eighty rectangular (25×4×2 mm) lithium disilicate glass-ceramic specimens were used in this study, 40 produced by heat pressing and 40 by milling, and divided into 4 groups (n=10) with a different number of veneer porcelain firings (1 to 4). After firing, the Vickers hardness, flexural strength (3-point bend test), and fracture toughness were determined, and the specimens were analyzed with an environmental scanning electron micrograph. Data were analyzed with analysis of variance (ANOVA) (α=.05). RESULTS The repeat firing processes did not affect the flexural strength of the specimens in either group (P>.05), while the surface hardness and fracture toughness were significantly changed (P<.05). CONCLUSIONS Increasing the number of firings adversely affected the mechanical properties of lithium disilicate glass-ceramics.
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Affiliation(s)
- Alper Ozdogan
- Assistant Professor, Department of Prosthodontics, Faculty of Dentistry, Atatürk University, Erzurum, Turkey.
| | - Hatice Ozdemir
- Associate Professor, Department of Prosthodontics, Faculty of Dentistry, Atatürk University, Erzurum, Turkey
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Porojan L, Vasiliu RD, Bîrdeanu MI, Porojan SD. Surface Characterization and Optical Properties of Reinforced Dental Glass-Ceramics Related to Artificial Aging. Molecules 2020; 25:molecules25153407. [PMID: 32731378 PMCID: PMC7435760 DOI: 10.3390/molecules25153407] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 07/24/2020] [Accepted: 07/26/2020] [Indexed: 11/16/2022] Open
Abstract
The development of various dental glass-ceramic materials and the evolution of novel processing technologies lead to an essential change in the clinical and technical workflow. The long-term success of a dental restoration treatment is defined by its durability, which is directly influenced by the oral environment. This study's purpose was to evaluate the artificial aging behavior of nanostructured, respective microstructured ceramics related to surface topography, roughness, and optical properties. Six monolithic restoration materials were selected: milled lithium disilicate glass-ceramic (LDS-M) MT (medium translucency), hot-pressed lithium disilicate glass-ceramic (LDS-P) MT and HT (high translucency), milled zirconia-reinforced lithium silicate ceramic (ZLS-M) MT and hot-pressed zirconia-reinforced lithium silicate ceramic (ZLS-P) MT and HT, resulting n = 96 surfaces. All the samples were artificially aged by thermal cycling, and all investigations were made before and after thermal cycling. In terms of optical properties, differences recorded between ZLS and LDS ceramics are not significant. Thermal cycling increases the translucency of ZLS and LDS glass-ceramic materials significantly, with the most harmful effect on the pressed and polished samples. Micro- and nano roughness are significantly influenced by in vitro aging and a negative correlation was recorded. Glazed samples are characterized by significant rougher surfaces for all types of materials. On nanolevel, ZLS materials are significantly smoothed by thermal cycling.
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Affiliation(s)
- Liliana Porojan
- Department of Dental Prostheses Technology (Dental Technology), “Victor Babeș” University of Medicine and Pharmacy Timișoara, Romania, Eftimie Murgu Sq. no. 2, 300041 Timișoara, Romania;
| | - Roxana-Diana Vasiliu
- Department of Dental Prostheses Technology (Dental Technology), “Victor Babeș” University of Medicine and Pharmacy Timișoara, Romania, Eftimie Murgu Sq. no. 2, 300041 Timișoara, Romania;
- Correspondence: ; Tel.: +40-745225523
| | - Mihaela-Ionela Bîrdeanu
- National Institute for Research and Development in Electrochemistry and Condensed Matter, 300569 Timisoara, Romania;
| | - Sorin-Daniel Porojan
- Department of Oral Rehabilitation (Dental Technology), “Victor Babeș” University of Medicine and Pharmacy Timișoara, Romania, Eftimie Murgu Sq. no. 2, 300041 Timișoara, Romania;
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