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Bioactive and inert dental glass-ceramics
Abstract
The global market for dental materials is predicted to exceed 10 billion dollars by 2020. The main drivers for this growth are easing the workflow of dentists and increasing the comfort of patients. Therefore, remarkable research projects have been conducted and are currently underway to develop improved or new dental materials with enhanced properties or that can be processed using advanced technologies, such as CAD/CAM or 3D printing. Among these materials, zirconia, glass or polymer-infiltrated ceramics, and glass-ceramics (GCs) are of great importance. Dental glass-ceramics are highly attractive because they are easy to process and have outstanding esthetics, translucency, low thermal conductivity, high strength, chemical durability, biocompatibility, wear resistance, and hardness similar to that of natural teeth, and, in certain cases, these materials are bioactive. In this review article, we divide dental GCs into the following two groups: restorative and bioactive. Most restorative dental glass-ceramics (RDGCs) are inert and biocompatible and are used in the restoration and reconstruction of teeth. Bioactive dental glass-ceramics (BDGCs) display bone-bonding ability and stimulate positive biological reactions at the material/tissue interface. BDGCs are suggested for dentin hypersensitivity treatment, implant coating, bone regeneration and periodontal therapy. Throughout this paper, we elaborate on the history, processing, properties and applications of RDGCs and BDGCs. We also report on selected papers that address promising types of dental glass-ceramics. Finally, we include trends and guidance on relevant open issues and research possibilities. This article is protected by copyright. All rights reserved.
... The suitability of this ceramic material is explained by its biocompatibility, chemical resistance, high mechanical strength, and corrosion resistance. [11][12][13][14][15] Nowadays ceramic materials for dental restorations are the yttria-stabilized tetragonal zirconia ceramics (Y-TZP). ...
... As initial raw material for obtaining glazes, feldspars with a transparent melt, a large melting interval, and a relatively high viscosity are preferred, because with they are introduced simultaneously the main oxides such as silica, aluminum oxide, alkali, and alkaline earth oxides. [15][16][17][18][19][20] Ceramic restorations based on zirconium oxide are manufactured using the CAD/CAM technology. Computer-aided design (CAD) and computer-aided manufacturing (CAM) are modern technologies that use computers to collect data, design future dental prostheses, and manufacture a wide range of products. ...
... In addition, glazed ceramics can mimic the shine and character of a natural tooth and provide the necessary smoothness. [11][12][13][14][15] The development of the production of dental glazes is related to the composition, type, design, and quality of the coating glazes used, which are essentially multicomponent glasses of varied composition, which mainly contain SiO 2 , Al 2 O 3 , B 2 O 3 , BaO, Na 2 O, K 2 O, Li 2 O, CaO, MgO, ZnO, CeO 2 , SnO 2 , and ZrO 2 , etc. One of the most important properties of these glasses is to have a thermal expansion coefficient (CTE) close and lower than that of zirconia ceramics. ...
This study presents the development of multicomponent glasses for glaze layers for dental yttria‐stabilized tetragonal zirconia (Y‐TZP). The samples were melted in the temperature range of 1 250–1 400°C and were cast in water to obtain a frit. The frits were grounded to a powder with a particle size of less than 40 µm. To study the crystallization tendency of melted glasses, they were thermally treated at 800°C and X‐ray diffraction analyses were performed for both types of samples. The structure of the glasses was investigated by the Fourier‐transform infrared spectroscopy. The thermal expansion coefficient, CTE, the glass‐transition temperature, Tg, and the softening temperature, Ts, were defined. To test the glaze layer on zirconia ceramic, glass powders with different compositions were mixed with modeling fluid and applied on zirconia specimens and then fired at 800°C in a vacuum dental furnace. Scanning electron microscopy, SEM, was used to observe a cross‐section of the glass–ceramic contact on a glazed zirconia ceramic specimen. Glass with the highest content of alkaline oxides is characterized by the closest CTE to zirconium ceramics (10.10⁻⁶ K⁻¹), the greatest transparency and good fluidity, and shows good adhesion to the zirconia. The glaze layer is homogeneous without cracks, pores, and crystals.
... Ceramic materials are the most common restoration materials due to their excellent aesthetic properties (sufficient translucency) and durability (sufficient strength and chemical stability). 1 Dental glass-ceramics have excellent physical and chemical properties and have been well received by dentists and patients for their excellent aesthetic properties, low thermal conductivity, adequate mechanical strength, good biocompatibility, wear resistance, and chemical durability. 2,3 In the early 18th century, ceramics were first used in dentistry, and because of their low hardness, brittleness, and cumbersome manufacturing process, they were mostly used to create glazes to simulate natural teeth. 4 The development of Porcelain-fused-to-metal (PFM) restorations in the 1960s led to a new milestone in the use of dental materials. ...
... 10,11 The properties of glass-ceramics are mainly determined by the main crystal phase, there are silicate glass-ceramics system, aluminosilicate glass-ceramics system, fluorosilicate glass-ceramics system, phosphosilicate glass-ceramics, where the glass matrix and the number of grains, size, aspect ratio, alignment direction determines the physical properties, mechanical properties and optical properties of the material, making glass-ceramics have the advantages of metal and other ceramic repair materials cannot be compared. 2 The application of glass-ceramics ranges from single-crown restorations to full-mouth restorations and is widely promoted in the use of inlays, high inlays, veneers, partial crowns, all ceramic crowns, as well as implant abutments and implant crowns. 12 This article reviews the classification, performance requirements, toughening mechanism and their association with clinical performance, manufacturing and fabrication techniques of glass-ceramics in restorative dentistry, and provides an outlook on the development of glass-ceramics in restorative dentistry in order to obtain better quality restorative materials. ...
... 13 Glass-ceramics are made by adding or growing different crystals in the glass phase to increase the mechanical properties of the material while maintaining the aesthetic properties of the material. Commonly used clinical glass-ceramics include mica-based glass-ceramics, apatite-based glass-ceramics, leucite-based glassceramics, Li 2 Si 2 O 5 glass-ceramics, and zirconia-reinforced Li 2 Si 2 O 5 glass-ceramics (ZLS). ...
The use of glass‐ceramics in the medical field has grown significantly since the 1980s. With excellent aesthetic properties, semi‐translucency, outstanding mechanical properties, corrosion resistance, wear resistance and great biocompatibility and workability glass‐ceramics is one of the most commonly used materials in restorative dentistry and is widely used in veneers, inlays, onlays, all‐ceramic crowns, and implant abutments. This review provides an overview of the research progress of glass‐ceramics in restorative dentistry, focusing on the classification, performance requirements, toughening mechanisms and their association with clinical performance, as well as the manufacturing and fabrication of glass‐ceramics in restorative dentistry. Finally, the developments and prospects of glass‐ceramics in restorative dentistry are summarized and discussed.
... Due to their biocompatibility and optical properties, their use for manufacturing highly esthetic monolithic single tooth FDPs, partial crowns, veneers, or veneering material for ceramic and metallic frameworks has been established [1][2][3]. Feldspar glass-ceramics are considered as a gentle restoration material for natural antagonistic teeth, in terms of hardness (2.4-6.5 GPa [4,5], Enamel: 3-5.3 GPa [6][7][8][9]) and E-modulus GPa [4], Enamel: 48-105.5 GPa [7,8,10]). Clinical studies have reported success rates for milled feldspathic glass-ceramic FDPs from 84 % to 95 % over periods of 9-18 years [11][12][13][14][15]. Exceptional esthetic qualities, including translucency and color matching to natural teeth, render them particularly suitable for anterior restorations where aesthetic outcomes are paramount. ...
... Due to their biocompatibility and optical properties, their use for manufacturing highly esthetic monolithic single tooth FDPs, partial crowns, veneers, or veneering material for ceramic and metallic frameworks has been established [1][2][3]. Feldspar glass-ceramics are considered as a gentle restoration material for natural antagonistic teeth, in terms of hardness (2.4-6.5 GPa [4,5], Enamel: 3-5.3 GPa [6][7][8][9]) and E-modulus GPa [4], Enamel: 48-105.5 GPa [7,8,10]). Clinical studies have reported success rates for milled feldspathic glass-ceramic FDPs from 84 % to 95 % over periods of 9-18 years [11][12][13][14][15]. Exceptional esthetic qualities, including translucency and color matching to natural teeth, render them particularly suitable for anterior restorations where aesthetic outcomes are paramount. ...
... This phenomenon is called stress shielding [60], whereby the osteocytes lose their main role (i.e., the preservation of the extracellular matrix), resulting in a reduction in the bone density of the jawbone, and eventually in the failure of the dental implant. The high elastic modulus of commonly-used dental implant materials like titanium alloys and zirconia (110 and 220 GPa, respectively) compared to the jawbone (7-30 GPa) and dentine (15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30) [31,[61][62][63][64] is a common cause of implant failure and decreased bone density post-implantation. Bone grafts are utilized in various clinical scenarios when a patient's jawbone fails to meet the necessary criteria for optimal dental implant placement (specifically, due to insufficient bone quantity resulting from tooth loss) [31,[62][63][64]. ...
... Initially, autogenous and allograft jawbone grafts were employed for their osteogenic and osteoinductive/osteoconductive properties, respectively. Subsequently, researchers redirected their focus towards synthetic materials (hydroxyapatite, tricalcium phosphates, bioactive glasses and GCs) to overcome the drawbacks associated with traditional grafts (such as patient discomfort, infection, complex surgical procedures, non-simultaneous absorption of the graft/new bone formation) and reduce costs [61][62][63][64][65][66][67]. ...
Bioactive glasses in the CaO-MgO-Na 2 O-P 2 O 5-SiO 2-CaF 2 system are highly promising materials for bone and dental restorative applications. Furthermore, if thermally treated, they can crystallize into diopside-fluorapatite-wollastonite glass-ceramics (GCs), which exhibit appealing properties in terms of mechanical behaviour and overall bone-regenerative potential. In this review, we describe and critically discuss the genesis, development, properties and applications of bioactive glass "1d" and its relevant GC derivative products, which can be considered a good example of success cases in this class of SiO 2 /CaO-based biocompatible materials. Bioactive glass 1d can be produced by melt-quenching in the form of powder or monolithic pieces, and was also used to prepare injectable pastes and three-dimensional porous scaffolds. Over the past 15 years, it was investigated by the authors of this article in a number of in vitro, in vivo (with animals) and clinical studies, proving to be a great option for hard tissue engineering applications.
... Lithium disilicate glass-ceramics, characterized by their unique microstructure of interlocking needle-like crystals within a glassy matrix, are produced through a two-phase process involving the mixing, melting, and cooling of raw materials with nucleating agents to form a precursor glass, followed by controlled heat treatment for nucleation and crystal growth [4,[9][10][11][12]. These glass-ceramics are essential in restorative dentistry due to their high mechanical strength, capable of enduring chewing forces up to 880 N [13], and their specific hardness close to 400 Vickers, similar to human dental enamel, to reduce wear [14]. Aesthetically, they offer suitable color and translucency tailored for various dental applications. ...
... Branched polyethyleneimines were formed in which the intensity of 3000-3700 cm − 1 (O-H stretching) was significate smaller than the band of 2800-2950 cm − 1 (C-H stretching). The peaks of primary amine were located at 1610 and 1520 cm − 1 [14]. As increased the PEI ratio, the N-H stretching band (3000-3700 cm − 1 ) was stronger. ...
... 33 A recent study by Prithiviraj et al. 34 indicated that most of the information in most of these apps is of poor accuracy; consequently, there is a potential for developing high-quality apps containing evidence-based information to improve patient care and aid professional development. [35][36][37] It is necessary to do more research to determine whether orthodontists are aware of these applications and whether they have recommended that their patients use them. In addition, there is a considerable variation in the interventions and outcome measures applied in the earlier studies. ...
... 11,35 Bioglass 45S5, BonAlive, solgel-derived bioglass 77S and 58S, icons doped BG etc. manufactured in various sizes have been proposed as bone graft substitutes in the market. 36,37 Even though quantities of processing techniques have been explored to improve the mechanochemical and biological properties of CaXs, it is still difficult to meet the requirements of various bone defects. 29 In recent decades, some strategies in combination with growth factors (GFs), namely, bone morphogenetic proteins (BMPs), vascular endothelial growth factors (VEGFs) and platelet-rich plasma (PRP). ...
Background:
Periodontal disease poses a significant global health challenge. Traditional treatments focus on reducing inflammation and bacterial load, yet novel approaches are continually being investigated. Recent research suggests that IL-37, a potent anti-inflammatory cytokine, may play a crucial role in modulating the inflammatory processes associated with periodontal disease. In conjunction with IL-37, low-level laser therapy (LLLT) has gained attention for its potential in promoting tissue repair, reducing inflammation, and enhancing cellular processes. This study aims to investigate the effects of LLLT on IL-37 in periodontal disease management.
Methods:
Thirty patients were enrolled: the G1 group patients were treated with only scaling and root planning-SRP, the G2 group was treated with SRP and LLLT. Before treatment (T0) all periodontal probing pocket depth and bleeding on probing were obtained. Before (T0) and 10 (T1), 30 (T2) and 60 (T3) days after treatment, was achieved plaque sample and specimens of gingival crevicular fluid. Diode laser wavelength range was used between 600-1000 nm and 0.04-60 J/cm2 energy density for 3-s spotlights.
Results:
In all patients PPD, BOP and IL-37 have shown healing improved parameters.
Conclusions:
Although LLLT is widely recommended for its biostimulatory and anti-inflammatory roles, it only showed additional short-term merits in reducing the pocket depth after conventional SRP. Its long-term adjunctive benefits remain unclear. Future RCTs with better study designs, adequate sample power and longer durations of follow-up are required to assess the effectiveness of LLLT as an adjunctive treatment strategy in patients with periodontal disease.
... LS glass-ceramic has also been proposed for orthopaedic applications [3], but is limited by its low bioactivity. The bioactivity of glass ceramics is mainly determined by the chemical component and controlled crystallization, which has been stated in previous research [4]. ...
... In addition, the hydrated silica on the surfaces of glass ceramics allows for the nucleation of apatite. The migration of Ca 2+ and PO 4 3− to the surface of the SiO 2− rich layer acts to form an amorphous CaO-P 2 O 5 rich (ACP) film. With the accumulation of OH − and CO 3 2− from the solution, the crystallization of ACP film forms hydroxycarbonate-apatite [47]. ...
Lithium silicate (LS) glass ceramic with excellent mechanical performance has been used in dental restoration but is seldom used in orthopedics due to its limited bioactivity. Given the osteoconductive features of calcium phosphate-based ceramics, optimizing the P2O5 content to adjust the ratio of CaO to P2O5 may improve the bioactivity of glass ceramics. The effect of P2O5 content on the phase formation, mechanical performance, cell
proliferation, cell differentiation and mineralization of glass ceramics were investigated in this study. The results indicated that increasing the content of P2O5 increased the formation temperature of LiAlSi2O6 and provided nucleation sites for Li2SiO3 by forming Li3PO4 which, in turn, promoted the transformation from Li2SiO3 to Li2Si2O5. The phase morphology transformed from a lamellar shape to a columnar shape, and then formed an interlocking structure in the specific heat treatment. The phase transformation and formation of Li3PO4 improved
cell proliferation, cell differentiation, and mineralization of the glass ceramics. In particular, the glass ceramic with 2.58 mol% P2O5 (LS3) and 4.12 mol% P2O5 (LS4) promoted the expression of alkaline phosphatase (ALP) and achieved the strength requirement of bone. In conclusion, the bioactivity of the glass ceramics was enhanced by increasing the P2O5 content, and the bone-like structure on the surface of the glass ceramic with 4.12 mol% P2O5 may make this material suitable for orthopaedic applications.
... Recent advances in tissue engineering have led to the development of iondoped bioactive glass nanoparticles, which can increase the regenerative potential of these biomaterials [2,3,5]. Bioactive glasses can be synthesized via melting or sol-gel processes, with the latter producing porous structures suitable for tissue engineering applications [6,7]. Depending on the fabrication method, properties such as surface area, degradability, and mechanical strength may vary [7]. ...
Developing functional biomaterials with optimized properties is a major challenge in tissue engineering. Materials such as bioactive glasses have been widely studied due to their potential for bone regeneration. In the present study, we aimed to develop 45S5 bioactive glass functionalized with 10% PTH 1–34 and evaluate the effects of the biomaterial on bone regeneration and the healing of critical bone defects in female rats. The preparation of the biomaterial involved the production of 45S5 bioactive glass using the sol–gel technique, followed by melting and quenching. To this end, thirty female Wistar rats were randomly assigned to two groups: one with 5-mm critical bone defects in the calvaria and another with 3-mm defects in the tibiae. The defects were filled with either bioactive glass (BG) or bioactive glass functionalized with 10% teriparatide (BGTer). The animals were euthanized at 2- and 6-weeks post-operation, and their defects were analyzed using histological, histomorphometry, immunohistochemical, and biomechanical methods (via a three-point bending test). Data were statistically assessed using ANOVA and Tukey’s post hoc test, with a significance level of 5%. The results showed that PTH 1–34, associated with the bioactive glass, was successfully incorporated and had a positive effect on bone repair in the studied model. We concluded that the biomaterial minimized the potential side effects and complications associated with systemic administration by transforming PTH 1–34 into a localized delivery system, representing a significant innovation of medical bioengineering.
... Polymer is the most often used matrix material in composite materials [55]. CaSiO 3 is a kind of glass ceramic that has the ability to stimulate the growth and specialization of osteoblasts, which are cells responsible for bone formation [56]. Conversely, Te is extensively used in several domains. ...
While polyetherketoneketone is a high‐performance thermoplastic polymer, its hydrophobicity and inertness limit bone adhesion. This study aimed to evaluate a novel PEKK/CaSiO3/TeO2 nanocomposite, comparing it to PEKK/15 wt.% CaSiO3 and PEKK groups. The in vitro study, involving 90 discs (n = 30), assessed the cytotoxicity of all groups after 24, 72, and 168 h. The in vivo animal study, using cylinder‐type implants (n = 30), evaluated osseointegration through biomechanical push‐out tests, descriptive histopathological examinations of decalcified sections stained with hematoxylin and eosin, and histomorphometric analysis of new bone formation area after 2‐ and 6‐week healing intervals. The cytocompatibility of PEKK/15 wt.% CaSiO3/1 wt.% TeO2 composite confirmed its acceptance as a biomedical material. Additionally, in vivo study results showed that the PEKK/15 wt.% CaSiO3/1 wt.% TeO2 had the highest shear strength value and the highest new bone formation area compared to other experimental groups. The multimodal concept of adding CaSiO3 micro fillers and TeO2 nanofillers to PEKK produces a cytocompatible composite that enhances osseointegration and new bone formation in a rabbit's femur after 2‐ and 6‐week healing intervals.
... The ceramic substances biocompatibility in the environment of the mouth, has been tested by means of employing various methods (e.g., the test of cytotoxicity and the agar-diffusion test) [12]. ...
Aim: To investigate the impact of thermocycling ageing on the flexural strength of E-max cad and E-max press The objective of this research is to evaluate the impact of aging via various thermocycling protocols on the flexural strength of a feldspathic ceramic. Material and Methods: Thirty six bars of ceramic, ivoclar e max, with dimensions of 16×4×2 mm were utilized. Bars were distributed randomly into three groups (n=6) that were defined in accordance with the number of thermal cycles (TCy): G0-no TCy; G5000-5000 cycles of TCy, G10000-10 TCy. After aging, samples were subjected to a three-point bending test in a universal test machine with a speed of 1mm/min and a load of 1kgf until the catastrophic failure was reached. Results: Concerning the mechanical test, the following values of mean and standard deviation values (MPa), were obtained: G0cad (612.12± 83.16) ; G5000cad (445.44 ± 34.99); G10000cad (366.34± 41.30) and G0press (534.09±42.83) ;G5000press (428.68±17.40) and G10000press (382±38.49).Variance analysis of was conducted using the regression equation (p=0.387) and it showed that there was a significant correlation between the flexural strength and the thermal cycles number. Conclusion: One can conclude that aging in water per se through various temperature cycles numbers has an effect on the flexural strength of a feldspathic ceramic. The thermocycling of both type of lithium disilicate has negative effect on the flexural strength, Cad ceramic showed more significant decrease in flexural strength than press ceramic which was less negatively affected.
... Over the years, technological advancement has led to monolithic lithium disilicate-based glass-ceramics (LDGCs) for dental applications. Their main characteristics are superior fracture resistance (360 ± 60 MPa) and toughness (3.0 ± 0.5 MPa.m ½ ), biocompatibility, superior aesthetics, color and chemical stability, translucency, and great machinability of the lithium metasilicate (LM) phase (1.1 ± 0.3 mm/ min) [1][2][3][4][5] that is pre-crystallized in the GCs before the machining operation. This impressive set of properties co-occurred with the advancement of computer-aided design technologies and computer-aided fabrication technology (CAD/CAM), which further boosted the use of LDGCs, making them a material of choice for indirect restorations in dental practice [3]. ...
Objective: This study aimed to evaluate the chemical solubility (CS) and conduct a comprehensive physicochemical characterization of several experimental and commercial lithium silicate-based glass-ceramics towards an understanding of the chemical processes governing dissolution in these glass-ceramics.
Methodology: Glass-ceramic (GC) samples were categorized into two groups: experimental materials featuring lithium metasilicate crystals (GCE1 and GCE2); and five commercial brands relying mostly on lithium disilicate (Celtra®Duo, IPS e.max®CAD, Straumann®n!ce®, CEREC Tessera™, and VITA Suprinity®). CS was assessed by submerging samples in a 4 % acetic acid solution following ISO 6872 standards. High-resolution inductively coupled plasma mass spectrometry (HR-ICP-MS) was employed to evaluate ion leaching from the residual acetic acid solution. Surface roughness and chemical composition were scrutinized using Atomic Force Microscopy (AFM) and X-Ray Photoelectron Spectroscopy (XPS), respectively.
Results: All groups met the CS standards. Kruskal-Wallis with the Dunn post-hoc test was used for CS, two-way ANOVA for roughness, and three-way ANOVA for XPS, each followed by Tukey’s post-hoc test (α=0.05). AFM revealed no significant alteration in surface roughness post-immersion for the majority of the groups, except for IPS e.max®CAD (p < 0.001). XPS detected compositional changes in all GCs following CS testing. HR-ICP-MS indicated a higher leaching of Li+ions (as expected) across all groups.
Conclusion: This study supports the understanding of the chemical processes that govern the dissolution of glass-ceramics and evaluate how different formulations influenced the CS and elemental composition. In this sense, the GCE2 group exhibited the most favorable properties for dental applications, mirroring the performance of the main commercial materials.
... In this context, glass-ceramics, particularly Li 2 O-2SiO 2 (lithium disilicate-LS2)-based systems, have gained considerable attention because of their low solubility in the oral environment, excellent mechanical properties, high translucency, and esthetics qualities. These attributes make them suitable for various dental applications, including crowns, onlays, inlays, and bridges [4]. Beyond their biocompatibility and mechanical properties, these materials are highly machinable by Computer-Aided Design & Computer-Aided Manufacturing (CAD/CAM) systems [2]. ...
... The low solubility and high chemical stability of the crystalline phases minimize the release of potentially harmful ions into the body, making these coatings safe for long-term use. Additionally, the resistance to biofouling and microbial colonization is an important factor in preventing infections and ensuring the longevity of the implants [124,125]. ...
... Contemporary and effective dental materials processed by computer-aided-design and computer-aided-manufacturing (CAD/CAM) technology are one of the most commonly used restorative materials in dental implantology together with materials used for 3D printing or tissue engineering. The variety of modern CAD/CAM silicate ceramics that have been expanding for several decades are commonly divided on the basis of differences in microstructure, which means variations in amount or type of crystalline and amorphous phases [1][2][3][4][5][6]. Currently, among the most widely used all--ceramic types in dentistry are glass-ceramics and zirconia oxide ceramics [8][9][10]. ...
... This is because biocompatibility has a direct impact on several key aspects, including allergic reactions, toxic reactions, bacterial infections, and oral ecological balance. 68,69 Moreover, color stability, durability of mechanical properties, and the long-term effect of the restorative material on the surrounding hard or soft tissues are also parts of biocompatibility. ...
As a subserie of the dental ceramic material family, glass–ceramics are favored for their excellent aesthetic properties. The feasibility of current commercially available dental glass–ceramics applications has been proven, while the assurance and development of more functional properties for them are still being explored. Effective utilization of various modification mechanisms by adjusting the chemical composition and microstructure is essential to improve the mechanical properties, aesthetic properties, and other properties such as biocompatibility of dental restorative materials. Among them, the mechanical properties of restorations should take into account the mechanical properties of glass ceramics and the final restoration (restoration and tooth set) in the mechanical behavior. This paper provides an overview of the chemical composition design, classification of microstructure, property requirements, and strengthening methods applied to dental glass–ceramics, including ion exchange, chain effects, heat treatment modulation, and strengthening mechanisms. In addition, research on traditional hot pressing, subtractive manufacturing, and newly developed additive manufacturing in glass–ceramics are systematically presented. Finally, the tendency of dental glass–ceramics was forecasted by analyzing the relationship between glass–ceramic composition, process, and mechanical properties.
... Ceramic materials attract increasing interest for producing fixed prosthetic restorations [1,2]. All-ceramic zirconia/ceramic-veneer dental restorations are attractive for both the dentists and the patients due to the excellent aesthetics, the ability to cover dark tooth cores or titanium implant abutments, high mechanical strength, and the excellent fit The production of dental restorations that use yttriastabilized tetragonal zirconia polycrystals (Y-TZP) with computer-aided design and manufacturing (CAD-CAM) technology manifests significant advantages, such as high flexural strength, satisfactory esthetics, reduced laboratory time, and fewer dental sessions [5,6]. ...
This study aimed at examining the bond strength between zirconia and ceramic veneer, following the ISO 9693 guidelines. A total of fifty specimens of zirconia/ceramic‐veneer system were produced using two commercial zirconias (VITA YZ‐HT White and Zolid HT+ White, referred to as Group A and Group B, respectively) and a ceramic‐veneering material (Zirkonia 750). The microstructure (via x‐ray diffraction analysis, XRD and Secondary Electron mode, SEM) and the mechanical properties (via 3‐point bending tests) of the two groups were assessed. Then, experiments were conducted according to the ISO 9693 and conventional protocols applied for producing zirconia/ceramic‐veneer restorations. Bond strength values, measured by 3‐point bending tests, were 34.42 ± 7.60 MPa for Group A and 31.92 ± 6.95 MPa for Group B. SEM observations of the cohesively fractured surfaces (on the porcelain side) and the examination for normality using the Shapiro–Wilk test suggested the use of Weibull statistical analysis. Median strength (σ 50% ) for Group A and Group B was 34.76 and 32.22 MPa, while the characteristic strength (σ 63.2% ) was 35.78 and 33.14 MPa, respectively. The Weibull modulus disparity between groups (12.69 and 13.07) was not significant. Bond strength exceeded the ISO 9693 minimum of 20 MPa, suggesting satisfactory strength for clinical use.
... 8 These implants also have a lower thermal conductivity compared to metal implants, which can reduce sensitivity and discomfort in the mouth, often experienced as unpleasant by the patient. 9 Whereas ceramic implants are still relatively new, research has shown promising results in terms of their long-term success rates and durability. ...
In this narrative review, a structured comparison between one-piece and two-piece zirconia dental implants is highlighted. Ceramic dental implants have long ceased to be hype; on the contrary, they can offer a significant addition to the daily dental implant practice. Not only do their favourable aesthetics play a significant role, but their ability to work completely metal-free is of added value, particularly for patients with a proven allergy for Grade 5 titanium. Furthermore, the fact that peri-implantitis seems to appear only incidentally is an important supporting argument for their use as well. Whereas the original design of zirconia implants was formerly always of a one-piece/one-phase structure (the monobloc design), nowadays, two-piece/two-phase designs (the so-called hybrid concept) are also widely utilised to restore missing teeth. Both concepts have advantages and disadvantages, scientifically as well as clinically.
For this paper, relevant articles from the recent scientific literature were selected from PubMed. The aim was to identify and summarise what has previously been published on one-piece versus two-piece ceramic implants. This article will compare the benefits and drawbacks of one-piece versus two-piece ceramic implants based on clinical- (design, different sizes, surgical protocol, prosthetics), scientific- (loading and eventual complications) and patient-related (costs and long-time perspectives) criteria.
... 6,7 Glass-ceramics, also known as microcrystalline glass, is a kind of ceramic material obtained by heat treatment of base glass, containing both crystalline and glass phases. 8,9 It combines the advantages of both ceramic and glass and has high mechanical properties while still Tong Zhang and Jinrong Liu are equally to the work as co-authors. maintaining good clarity, which makes it an essential part of all-ceramic materials. ...
Lithium disilicate (Li2Si2O5) glass‐ceramics are currently a more widely used all‐ceramic restorative material due to their good mechanical properties and excellent aesthetic properties. However, they have a series of problems such as high brittleness and low fracture toughness, which has become the main bottleneck restricting its development. Therefore, in order to compensate for these shortcomings, we propose to prepare a reinforced glass‐ceramics with better mechanical properties and to test the biosafety and chemical solubility of the material. Li2Si2O5 whiskers were synthesized by a one‐step hydrothermal method, and multi‐scale crystal‐enhanced Li2Si2O5 glass‐ceramics were prepared by reaction sintering. The biosafety of multi‐scale crystal‐reinforced Li2Si2O5 glass‐ceramics was investigated by in vitro cytotoxicity test, rabbit pyrogen test, mice bone marrow micronucleus test, skin sensitization test, sub‐chronic systemic toxicity test, and chronic systemic toxicity test. Additionally, the chemical solubility of multi‐scale crystal‐reinforced Li2Si2O5 glass‐ceramics was investigated. The test results showed that the material was non‐cytotoxic, non‐thermogenic, non‐mutagenic, non‐sensitizing, and non‐systemic. The chemical solubility, determined to be 377 ± 245 μg/cm², complied with the ISO 6872 standard for the maximum solubility of ceramic materials. Multi‐scale crystal‐reinforced Li2Si2O5 glass‐ceramics' biosafety and chemical solubility met current normative criteria, and they can move on to mechanical property measurements (such as flexural strength test, fatigue life test, friction and wear property study, etc.) and bonding property optimization, which shows promise for future clinical applications.
... Due to good mechanical properties, resistance to abbrasion, attractive optical features, etc. Other G-Cs have been applied in radar and navigational devices, military hardware, construction materials, kitchen and cooking wares, medical materials, human tissue substitutes, electronics, and optical materials, among others [4][5][6][7][8][9]. Similar to glasses and ceramics, G-Cs, being composite materials, are also attractive as radiation shields. ...
The Li2O-Al2O3-SiO2 (LAS) glass system has high commercial values due to its very low thermal expansion coefficients and its very high chemical resistance among other properties. In this study, the preparation of LAS-based glass–ceramics (G-Cs) is reported, and the influence of P2O5 as a nucleating agent for crystallizing the amorphous glass structure at different rates into this glass composition, on the physical, structural, and mechanical properties is presented. The influece of different crytalization temperature on the crystal size and micreostructure as well as the radiation absorption abilities of the G-Cs were also investigated. The G-Cs were prepared using the melt and quench method and subjected to different temperature regimes to crystallise. The crystallinity of the prepared samples was examined with the aid of X-ray Diffraction analysis, while their chemical composition was probed using energy dispersive spectroscopy (EDS). The mass attenuation coefficients (MACs) of the samples were estimated for 15 keV–15 MeV photons using the well-known WinXCom software. Lithium silicate with the main phase formulation Li0.75Al0.75Si2.25O6 was identified as the main crystalline phase within the residual glass phase. The increase in P2O5 content slightly diminishes the photon absorption abilities of the G-Cs. However, the G-Cs showed better photon absorption prowess compared to some notable shielding materials. The G-Cs are thus important shielding materials useful for radiation control purposes.
... Lithium disilicate (Li 2 Si 2 O 5 , written as LD) glass-ceramics, the microstructure of which features interlocked rod-like LD crystals embedded in glass matrix [1][2][3], have gained much attention in prosthetic dentistry since 1998 [4]. In recent years, a novel restorative material, polymer-infiltrated-ceramic-network material (PICN), has gained researchers' attention [5][6][7]. ...
Using melt-derived LD glass powders and 5–20 M NaOH solutions, porous lithium disilicate (Li2Si2O5, LD) glass–ceramics were prepared by the cold sintering process (CSP) associated with the post-annealing technique. In this novel technique, H2O vapor originating from condensation reactions between residual Si–OH groups in cold-sintered LD glasses played the role of a foaming agent. With the increasing concentration of NaOH solutions, many more residual Si–OH groups appeared, and then rising trends in number as well as size were found for spherical pores formed in the resultant porous LD glass–ceramics. Correspondingly, the total porosities and average pore sizes varied from 25.6 ± 1.3% to 48.6 ± 1.9% and from 1.89 ± 0.68 μm to 13.40 ± 10.27 μm, respectively. Meanwhile, both the volume fractions and average aspect ratios of precipitated LD crystals within their pore walls presented progressively increasing tendencies, ranging from 55.75% to 76.85% and from 4.18 to 6.53, respectively. Young’s modulus and the hardness of pore walls for resultant porous LD glass–ceramics presented remarkable enhancement from 56.9 ± 2.5 GPa to 79.1 ± 2.1 GPa and from 4.6 ± 0.9 GPa to 8.1 ± 0.8 GPa, whereas their biaxial flexural strengths dropped from 152.0 ± 6.8 MPa to 77.4 ± 5.4 MPa. Using H2O vapor as a foaming agent, this work reveals that CSP associated with the post-annealing technique is a feasible and eco-friendly methodology by which to prepare porous glass–ceramics.
... The chemical characterisation indicates the concurrent presence of several lithium species within LipSiNs. These species include crystalline lithium silicates which contribute to the stabilisation of the surface of the nanowires and are expected to slow the release kinetics 41,42 . Alongside the more stable silicate species, LipSiNs contain amorphous lithium which contributes soluble material for rapid release. ...
Periodontal disease is a significant burden for oral health, causing progressive and irreversible damage to the support structure of the tooth. This complex structure, the periodontium, is composed of interconnected soft and mineralised tissues, posing a challenge for regenerative approaches. Materials combining silicon and lithium are widely studied in periodontal regeneration, as they stimulate bone repair via silicic acid release while providing regenerative stimuli through lithium activation of the Wnt/β-catenin pathway. Yet, existing materials for combined lithium and silicon release have limited control over ion release amounts and kinetics. Porous silicon can provide controlled silicic acid release, inducing osteogenesis to support bone regeneration. Prelithiation, a strategy developed for battery technology, can introduce large, controllable amounts of lithium within porous silicon, but yields a highly reactive material, unsuitable for biomedicine. This work debuts a strategy to lithiate porous silicon nanowires (LipSiNs) which generates a biocompatible and bioresorbable material. LipSiNs incorporate lithium to between 1% and 40% of silicon content, releasing lithium and silicic acid in a tailorable fashion from days to weeks. LipSiNs combine osteogenic, cementogenic and Wnt/β-catenin stimuli to regenerate bone, cementum and periodontal ligament fibres in a murine periodontal defect.
... F, such a glass composition ranges from (4-15)P 2 O 5 -(42-59)SiO 2 -(7-15)Li 2 O-(15-28)ZrO 2 in wt.%. [116][117][118] Viscous flow of asprepared glass-ceramic ingots in heat-pressing furnaces produce the glass-ceramic products. In a glass-ceramic containing 16 wt.% ...
This article reviews promising studies on the design, manufacturing, microstructure, properties, and applications of glass-ceramics containing ZrO2 and relevant glass-ceramic matrix composites. After the addition of ZrO2 to a glass-ceramic composition, it can persist in the residual glassy phase, facilitate nucleation, and/or precipitate as ZrO2 or another zirconate crystalline phase. Also, ZrO2-reinforced or ZrO2-toughened glass-ceramics can be designed as composites. In this article, the term “ZrO2-containing glass-ceramics” encompasses all these scenarios in which ZrO2 is present. Such glass-ceramics offer a wide range of applications in modern industries, including but not limited to architecture, optics, dentistry, medicine, and energy. Since S. Donald Stookey's discovery of glass-ceramics in the early 1950s, the most important scientific efforts reported in the literature are reviewed. ZrO2 is commonly added to glass-ceramics to promote nucleation. As a result, the role of ZrO2 in structural modification of residual glass and stimulating the nucleation in glass-ceramic is first discussed. ZrO2 can also be designed into the main crystalline phase of glass-ceramics, contributing achieving super high fracture toughness above 4 MPa·m0.5. Experimental and computational studies are reviewed in detail to elucidate how the transformation toughening and other mechanisms help to achieve such high values of fracture toughness. Sintered and glass-ceramic matrix composites also show promise, where ZrO2 contributes to improved stability and mechanical properties. Finally, we hope this article will provoke interest in glass-ceramic materials in both the scientific and industrial communities so that their tremendous technological potential in developing, for example, tough, thermally stable, transparent, and biologically compatible materials can be realized more widely.
... All rights reserved. as bioactive materials in hard and soft tissue regeneration [1][2][3][4][5] . BGNs are also characteristic of regulable morphology and particle size, and large specific surface area, consequently leading to great acellular and cellular bioactivity [ 1 , 6 ]. ...
... 11,35 Bioglass 45S5, Bonalive, solgel-derived bioglass 77S and 58S, icons doped BG etc. manufactured in various sizes have been proposed as bone graft substitutes in the market. 36,37 even though quantities of processing techniques have been explored to improve the mechanochemical and biological properties of caXs, it is still difficult to meet the requirements of various bone defects. 29 in recent decades, some strategies in combination with growth factors (GFs), namely, bone morphogenetic proteins (BMPs), vascular endothelial growth factors (VeGFs) and platelet-rich plasma (PrP). ...
Abstract: regenerative medicine emerged as a promising strategy for addressing bone defects, with several bone grafts currently being used, including autografts, allografts, xenografts and alloplasts. calcium-based biomaterials (CaXs), a well-known class of synthetic materials, have demonstrated good biological properties and are being investigated for their potential to facilitate bone regeneration. this systematic review evaluates the current clinical applications of caXs in dentistry for bone regeneration. Evidence acquisition: a comprehensive search was conducted to collect information about caXs and their applications in the dental field over the last ten years. The search was limited to relevant articles published in peer-reviewed journals. Evidence Synthesis: A total of 72 articles were included in this scoping review, with eight studies related to periodontology, 63 in implantology and three in maxillofacial surgery respectively. The findings suggest that CaXs hold promise as an alternative intervention for minor bone regeneration in dentistry. cONclUSiONS: calcium-based biomaterials have shown potential as a viable option for bone regeneration in dentistry. Further research is warranted to fully understand their efficacy and safety in larger bone defects. CaXs represent an exciting avenue for researchers and clinicians to explore in their ongoing efforts to advance regenerative medicine.
... This led to the development of second-generation zirconia, which was only suitable for posterior crowns and bridges [7]. In order to improve the esthetic performance of 3Y-TZP, while also protecting the opposing teeth from abrasion (since 3Y-TZP has a much higher hardness than the enamel of natural teeth, ∼12 and 3 -6 GPa, respectively) [1,9], researchers suggested covering 3Y-TZP frameworks with ceramic veneers [2]. Nevertheless, poor interfacial adhesion between the two dissimilar materials frequently led to chipping and delamination of the veneered porcelain [2]. ...
The present study aimed to compare the microstructure, physical, and mechanical properties of three commercially available dental polychromatic multilayer zirconia materials of uniform composition: Dima Mill Zirconia ML, VITA YZ/ST Multicolor, and VITA YZ/XT Multicolor (with 3, 4, and 5 mol% Y 2 O 3 , respectively); thus, the influence of Y 2 O 3 content on the above properties of the produced materials was experimentally studied. Homogeneous zirconia ceramics with a dense micro-and nanostructure, without pores or defects, were produced after milling the blocks and sintering, which resulted in yttrium-stabilized tetragonal and cubic zirconia. Statistical analysis of the results of measurable magnitudes was performed by the one-way ANOVA test. The increase of Y 2 O 3 content (from 3 to 5 mol%) favored larger grain and crystallite sizes and a decrease of the values of the mechanical properties; yet, the differences were statistically insignificant. Clinically, these differences are expected to have no impact on their function in the oral cavity, both in terms of their fracture propensity and the damage that can be caused to the opposing teeth. Accordingly, the experimental results qualify the polychromic multilayer zirconia ceramics of uniform composition fabricated by milling technology for use in dental restorations. K E Y W O R D S dental fixed prosthetic restorations, mechanical properties, microstructure, subtractive manufacturing , zirconia: yttria stabilized
Fluorapatite glass-ceramics (FGC) have been widely used in dental ceramics due to their excellent aesthetic properties and biocompatibility. In recent years, new synthesis methods, forming technologies, and the continuous optimization of performance attributes have driven the application of FGC in dental veneers, coatings, composites, and other restorations. This review summarizes the current research and applications of this material in the dental field and looks forward to its future optimization directions. The article focuses on five aspects: the development of preparation techniques for FGC; advances in their application in dental restoration shaping technologies; the performance advantages and limitations of these materials as dental materials; the current application status in veneers, coatings, composites, and other restorations; as well as the challenges in the current applications and prospects. In addition, additive manufacturing technology shows extremely broad application potential in FGC molding and applications. This review is hoped to provide strong guidance for the further application of FGC in the dental field, promoting the integration of related research and industry upgrades better to meet the needs of clinical practice and patients.
The introduction of glass matrix ceramics in dental restorations has revolutionized dental aesthetics. A key challenge in the development of dental glass ceramics is achieving nanocrystalline glass ceramics with superior mechanical properties without compromising translucency. In this study, ZrO2–SiO2 glass ceramics doped with amorphous Al2O3 were investigated to address these requirements. The results indicate that the segregation of Al³⁺ at the grain boundaries of ZrO2 crystallites and the nano-domains of amorphous Al2O3 significantly influences the microstructure, including the grain size and stabilization of tetragonal ZrO2, as well as the translucency and mechanical properties. The composition with 10 mol% Al2O3 exhibits the highest toughness of 8.05 MPa∙m1/2 while maintaining excellent translucency. Moreover, the composition with 5 mol% Al2O3 demonstrates lower translucency but achieves a high flexural strength of 960 MPa. Overall, the mechanical properties of these translucent glass matrix ceramics surpass those of commercially available dental glass ceramics, highlighting their potential for dental restoration applications.
Bioceramics: Status in Tissue Engineering and Regenerative Medicine (Part 2) presents recent advancements in biocompatible ceramics and bioactive glasses, emphasizing their expanding applications in hard and soft tissue engineering. This book explores innovative manufacturing techniques like 3D printing and additive manufacturing and examines the therapeutic potential of bioceramics in areas such as bone regeneration, microbial infection management, wound healing, and cancer treatment. It also discusses current challenges, clinical applications, and future research directions. This book is a valuable resource for those developing biocompatible materials for medical applications. Key Features: - Comprehensive overview of bioceramic and bioactive glass applications in tissue engineering. - In-depth analysis of manufacturing techniques, including 3D printing and additive manufacturing. - Insights into clinical challenges, preclinical assessments, and future perspectives in regenerative medicine.
Bioceramics: Status in Tissue Engineering and Regenerative Medicine (Part 1) provides an in-depth look into the recent advancements in biocompatible ceramics, glasses, and composites for tissue engineering and regenerative medicine. It explores topics ranging from the structure and processing of bioactive glasses to the applications of bioinert and bioresorbable ceramics in medical treatments. The book discusses key aspects of bioceramics, including their therapeutic potential in soft tissue healing and cancer therapy, along with challenges and opportunities for future research. Researchers, bioengineers, and professionals in biomedical sciences will find this volume an essential resource for understanding both the fundamentals and applications of bioceramics. Key Features: - Comprehensive coverage of bioceramics, bioactive glasses, and composites, including their manufacturing techniques. - State-of-the-art insights into bioceramics and glass-ceramics in tissue engineering and regenerative medicine. - Focus on preclinical assessment, clinical applications, challenges, and future perspectives.
This publication pursues the goal of recording the steep and narrow path of the development of glass‐ceramics, starting from the initial idea to the product. It provides a guide for developers (whether chemists, materials scientists, engineers, or technologists) of glass‐ceramic products to develop materials with special properties and combinations of properties. At the same time, the publication illustrates the variety of possibilities for using these materials in diverse areas. These application areas reach from technology to dentistry and human medicine.
Advancement in medicine and technology has resulted into prevention of countless deaths and increased life span. However, it is important to note that, the modern lifestyle has altered the food habits, witnessed increased life-style stresses and road accidents leading to several health complications and one of the primary victims is the bone health. More often than ever, healthcare professionals encounter cases of massive bone fracture, bone loss and generation of critical sized bone defects. Surgical interventions, through the use of bone grafting techniques are necessary in such cases. Natural bone grafts (allografts, autografts and xenografts) however, have major drawbacks in terms of delayed rehabilitation, lack of appropriate donors, infection and morbidity that shifted the focus of several investigators to the direction of synthetic bone grafts. By employing biomaterials that are based on bone tissue engineering (BTE), synthetic bone grafts provide a more biologically acceptable approach to establishing the phases of bone healing. In BTE, various materials are utilized to support and enhance bone regeneration. Biodegradable polymers like poly-(lactic acid), poly-(glycolic acid), and poly-(ϵ-caprolactone) are commonly used for their customizable mechanical properties and ability to degrade over time, allowing for natural bone growth. PEG is employed in hydrogels to promote cell adhesion and growth. Ceramics, such as hydroxyapatite and beta-tricalcium phosphate (β-TCP) mimic natural bone mineral and support bone cell attachment, with β-TCP gradually resorbing as new bone forms. Composite materials, including polymer-ceramic and polymer-glasses, combine the benefits of both polymers and ceramics/glasses to offer enhanced mechanical and biological properties. Natural biomaterials like collagen, gelatin, and chitosan provide a natural matrix for cell attachment and tissue formation, with chitosan also offering antimicrobial properties. Hybrid materials such as decellularized bone matrix retain natural bone structure and biological factors, while functionalized scaffolds incorporate growth factors or bioactive molecules to further stimulate bone healing and integration. The current review article provides the critical insights on several biomaterials that could yield to revolutionary improvements in orthopedic medical fields. The introduction section of this article focuses on the statistical information on the requirements of various bone scaffolds globally and its impact on economy. In the later section, anatomy of the human bone, defects and diseases pertaining to human bone, and limitations of natural bone scaffolds and synthetic bone scaffolds were detailed. Biopolymers, bioceramics, and biometals-based biomaterials were discussed in further depth in the sections that followed. The article then concludes with a summary addressing the current trends and the future prospects of potential bone transplants.
Purpose
To study the effect of thickness difference on color change of glass ceramic materials.
Patients and methods
Sixty three specimens were divided according to type of the material into three groups ( n = 21) as follow Leucite based glass-ceramic (IPS Empress CAD), lithium disilicate based glass ceramic (IPS EMAX CAD), zirconia reinforced glass ceramic (celtra duo) and each group was further subdivided into three subgroups according to thickness (0.7, 1, 1.2 mm) seven each. The specimens were sawed by using linear precision saw, were square in shape and their dimension was 10 mm of length, 10 mm of width and three difference thicknesses (0.7, 1, 1.2 mm). The final thickness of specimens was confirmed with a digital caliper for standardization. Each group of specimens was finished according to its material manufacturer instruction, Cary 5000 Spectrophotometer provided from Agilent Technologies was used to measure color difference. One-way analysis of variance used to compare materials after glazing, multiple comparison Tukey test to compare each two materials.
Results
There was significant difference between all groups. At color width 0.7 and 1 mm, Celtra duo recorded the lowest color difference value while Empress recorded the highest color difference value. There was highly significant difference after glazing between materials where P value more than 0,001. At color width 0.7 and 1.2 mm, there was a highly significant difference after glazing between materials where P value is 0.001. Celtra duo showed the lowest color difference value while Emax and Empress showed equal values where P value more than 0.993. At color width 1 and 1.2 mm, Empress recorded the lowest color difference while Emax recorded the highest value. There was a highly significant difference between Emax versus Empress and Celtra duo versus Empress where P value was 0.001. On the other hand there was no significance recorded between Emax vs celtra duo where ( P > 0.984).
Conclusion
Masking abilities of glass ceramic are affected by ceramic thicknesses, background colors. The masking ability of glass ceramics tends to improve with greater thickness, while translucency decreased.
Abstract
Several nanomaterials have been recently used to overcome various challenges in the dental domain. Bioactive glasses, a class of bioceramics, with their outstanding properties including but not limited to their strong biocompatibility, antibacterial characteristics, and bioactivity inside the body's internal milieu have made them valuable biomaterials in a variety of dental domains. The utilization of nanomaterials has improved the performance of teeth, and the incorporation of bioactive glasses has the field of dentistry at an unsurpassed level in different categories such as esthetic and restorative dentistry, periodontics and dental implants, orthodontics, and endodontics. The current study discusses the most recent developments of the bioactive glasses’ creation and implementation for dental applications, as well as the challenges and opportunities still facing the field. This work provides an overview of the current obstacles and potential future prospects for bioactive glasses-based nanocomposites to improve their dental uses. It also emphasizes the great potential synergistic effects of bioactive glasses used with other nanomaterials for dental applications.
Since lithium-silicate glass-ceramics (LSCs) were introduced to dentistry, their formulations have been modified significantly to meet the multifaceted aesthetic and mechanical requirements of dental restorations. Therefore, the focus of this thesis was to investigate various spectrophotometric, topographic, and mechanical aspects of novel zirconia-reinforced lithium silicate glass-ceramics (ZLSs) as a function of different intaglio and external surface treatments. The first part of this research applied intaglio treatments of acid etching and/or acid neutralising combinations to CAD/CAM LSCs (e.max CAD, VITA Suprinity, Celtra Duo and CEREC Tessera). Ceramic-related properties (light transmission, absorbance, roughness, wettability, and flexural strength) and light curing unit-related properties (transmitted irradiance, power, and radiant exposure) were assessed. Post-etching neutralisation did not detrimentally alter the micro-retentive intaglio features, and, neutralised LSCs demonstrated relatively adequate aesthetic and mechanical stability. The second part of this thesis assessed external treatments of varying firing/glazing protocols applied to fully crystallised CAD/CAM LSCs (Initial LiSi Block, Celtra Duo and CEREC Tessera). Thereafter, light transmission, roughness, gloss, hardness, flexural strength and crystalline phases were evaluated. Overall, single and duplicate firing treatments yielded favourable strength results, whereas glazing led to the strength deterioration of fully crystallised LSCs. The third part analysed the stain susceptibility and topography of pressable and machinable ZLSs (VITA AMBRIA, Celtra Press, VITA Suprinity, and Celtra Duo). Stain susceptibility of ZLSs concluded to be dependent on their fabrication methods as well as translucency and thickness levels.
Objective
To describe the existing knowledge about metal-free prosthetic biomaterials according to their physicochemical properties and based on this, define criteria for their placement in both the anterior and posterior sectors.
Materials and methods
A digital search was carried out in the databases: PubMed/Medline, Scopus, Web of Science and Google Scholar of the literature published in the English language without time restrictions and included original articles such as case reports, retrospective and prospective studies, narrative, comprehensive, systematic reviews and meta-analysis. Meanwhile, short communications, editorials and articles in a language other than English were excluded.
Results
40 articles were evaluated, published between 2000 and 2023. The main characteristics and physicochemical properties of ceramic biomaterials such as zirconia, feldspathic based ceramics, lithium disilicate and alumina, among others, were analyzed and summarized. In addition, certain criteria were defined based on the available scientific evidence on the use of different ceramic systems both in the anterior sector and in the posterior sector for patients who need some type of prosthetic restoration.
Conclusions
Among the different metal-free materials used for the construction of fixed dental prostheses, zirconia has been shown to have better aesthetic, biomechanical and biocompatibility properties, which makes it a candidate material for the rehabilitation of partially edentulous patients.
IPS e.max Press, a lithium disilicate‐based glass ceramic, is renowned in dental restorations for its mechanical strength and aesthetic appeal. This study delves into its behavior within oral environments, employing electrochemical and surface analysis techniques. By utilizing cyclic polarization curves and impedance spectroscopy, we evaluated its degradation resistance. Surface morphology, composition, and crystal stability were explored through scanning electron microscopy (SEM)/energy‐dispersive X‐ray spectroscopy (EDX) and X‐ray powder diffraction (XRD) analysis. The glass ceramic exhibited robust resistance to localized degradation across all tested electrolytes. The degradation potential ( E corr ) varied with time and pH, indicating electrolyte influence. SEM/EDX affirmed oxide layer formation, while XRD confirmed a stable structure. While showcasing favorable resistance in saliva, citric acid, and lactic acid, IPS e.max Press demonstrated susceptibility to acetic acid. This comprehensive analysis enhances our understanding, providing valuable insights for the development of durable dental materials through a combination of electrochemical analysis and surface characterization.
Ceramics are inorganic nonmetallic materials (oxides, carbides, nitrides, etc.) processed after sintering of natural or synthetic precursors at high temperature. They can also be applied at or resist high firing temperatures. They are highly crystalline (most of the advanced and traditional ceramics), semi-crystalline (vitrified ceramics such as earthenware, stoneware, and porcelain), or completely amorphous (glasses). The composition/structure relationship, method of processing, raw materials, and applications determine the properties of ceramics and whether the ceramics are traditional or advanced ones. The first man-made ceramics were pottery objects and figurines from clays after firing. Several stages have been considered in the development of ceramic industry until reaching the production of advanced ceramics. The second stage for development of ceramic includes the production of glazed-colored ceramics, ceramic arts, and building products. Recently, new categories of advanced ceramics have been developed for electronics, biomedical, semiconductors, energy, and optical and structural applications. In the present chapter, we are going to shed light on the stages of development for advanced ceramics. Types and classifications, advanced processing techniques, properties, sintering as well as new forms of applications will be presented in the current chapter. Examples of these kinds of advanced ceramics, e.g., alumina, zirconia, Mg–Al spinels, silicon carbide, silicon nitride, ceramic composites, thin films, etc., with their specific applications will be also presented.
Glasses based on the basic composition of lithium disilicate (Li2O.2SiO2) together with derived samples containing increasing CeO2 replacing Li2O (0.1, 0.2, 0.5, 1 Mol %) were prepared by melting – annealing method, samples from the prepared parent glasses were thermally heat treated through two-step regime (450° C /10 h – followed by 650° C / 6 h) to convert them to their glass – ceramics derivatives. The main purpose of this study is to find out the main properties of the prepared glass – ceramics to be applied as dental candidates. The optical, FTIR, and thermal expansion properties of the parent glasses were examined to identify the main structural groups which are defined as tetrahedral stronger SiO2 building groups. The detailed separated crystalline phases within the prepared glass–ceramics were identified together with their textural features. The Vickers microhardness data for both the parent glasses and their glass -ceramics derivatives were evaluated. SEM and EDAX measurements indicate the ability of the prepared samples to form hydroxyapatite upon immersion in SBF solution.
Thermal spraying of metal materials is one of the key applications of this technology in industry for over a hundred years. The variety of metal-based feedstocks (powders and wires) used for thermal spray is incredibly large and utilization covers abrasion and corrosion protection, as well as tribological and electrical applications. Spraying metals using suspension- or precursor-based thermal spray methods is a relatively new and unusual approach. This publication deals with three metal types, a NiCr 80/20, copper (Cu), and silver (Ag), sprayed as fine-grained powders dispersed in aqueous solvent. Suspensions were sprayed by means of high-velocity suspension spraying (HVSFS) employing a modified TopGun system. The aim was to prepare thin and dense metal coatings (10–70 µm) and to evaluate the process limits regarding the oxygen content of the coatings. In case of Cu and Ag, possible applications demand high purity with low oxidation of the coating to achieve for instance a high electrical conductivity or catalytic activity. For NiCr however, it was found that coatings with a fine dispersion of oxides can be usable for applications where a tunable resistivity is in demand. The paper describes the suspension preparation and presents results of spray experiments performed on metal substrates. Results are evaluated with respect to the phase composition and the achieved coating morphology. It turns out that the oxidation content and spray efficiency is strongly controlled by the oxygen fuel ratio and spray distance.
The aim of this study was to evaluate the in vitro and in vivo osteogenic potential of the bioactive glass-ceramic scaffold (Bio-Sca). Rat mesenchymal stem cells (MSCs) were cultured on either dense Bio-Sca discs and or polystyrene (control) under non-osteogenic conditions. At day 10, alkaline phosphatase (ALP) activity and gene expression of the bone markers ALP, runt-related transcription factor 2 (Runx2), osteopontin (OPN) and osteocalcin (OCN) were evaluated. Rat calvaria surgical defects were implanted with porous Bio-Sca and at 4, 8 and 12 weeks histological analisys and bone volume (BV), bone surface (BS), bone volume/tissue volume ratio (BV/TV), bone surface/bone volume ratio (BS/BV), trabecular number (TbN-1), trabecular thickness (Tb.Th) and trabecular separation (Tb.Sp) measuremets were performed. Empty defects were used as control. Data were compared by either Mann Whitney (in vitro) or Kruskal-Wallis (in vivo) and Student-Newman-Keuls test, when appropriated. MSCs cultured on Bio-Sca displayed higher ALP activity and gene expression of all evaluated bone markers (p=0.03 for all parameters) compared with TCP, indicating that this biomaterial promotes osteoblast differentiation. The histological analysis revealed a meaningful bone formation into Bio-Sca implanted defects without relevant differences over time, while no bone formation was observed into control defects. Among all evaluated parameters of bone formation, only BS/BV (p=0.02) was affected by implantation period, being higher at 8 weeks. Our results showed that Bio-Sca induces osteoblastic differentiation of MSCs under non-osteogenic conditions what could explain bone formation in non-repairing defects. Thus, this novel scaffold may be considered a good candidate to be used in bone tissue engineering procedures. Acknowlegments: CNPq and FAPESP
A series of glass compositions with varying equimolar amounts of Na2O:Al2O3 were designed using Appen factors. High purity batch reagents were ball milled for 30 min and transferred to Pt/Rh crucible and melted in an electric furnace (EHF1700, Lenton, UK) at high temperatures then held for 90 min. The molten glass was poured into a graphite mould, annealed at 50°C below the glass transition temperature for 1h and the remaining glass was quenched into water. Glass frits were crushed and ball milled into powders with different particle sizes. Glass powders (PS<125μm) were heat-treated via two-step heat treatment cycles and air quenched. Experimental glasses and glass-ceramics were characterised using X-Ray Diffraction (XRD), Dilatometry, Scanning Electron Microscopy (SEM) and solid state Nuclear Magnetic Resonance (NMR).
Ceramic materials are among the most biocompatible materials developed for dental restorations. The interest in all-ceramic restorations has rapidly increased over the past decade as stronger, tougher and more aesthetic materials are developed, along with novel processing technologies such as hot pressing and CAD/CAM (computer-aided design/computer-assisted manufacture[1] . Ceramics are widely used in dentistry because of their natural appearance and excellent mechanical, optical, thermal and chemical properties[2]. Dental ceramics exhibit many desirable material properties, including biocompatibility, chemical inertness, aesthetics, compressive strength, diminished plaque accumulation, low thermal conductivity, abrasion resistance and colour stability [2, 3] . However, the possible applications for dental all-ceramic restorations are limited due to their brittle nature, sensitivity to flaws and defects, low tensile strength and fracture toughness[4]. The presence of numerous surface and internal flaws, which may develop as a result of thermal, chemical or mechanical processes, can act as stress concentrators, reducing the strength of ceramics. These stresses can cause cracks to originate from the defect site which can propagate and lead to catastrophic failure[5]. New materials and different processing methods have been introduced in recent years in an attempt to overcome these inherent problems. This review covers the development of dental ceramics including the history, classification and description of the different types of material, fabrication technologies, and mechanical and physical properties. Emphasis is placed on how these new materials and processing methods are overcoming the aforementioned problems. Clinical trials and longevity data is covered along with preparation guidelines. The evolution of all-ceramic restorations is addressed and focus is placed on high strength core ceramics and resin bonded glass-ceramic restorations. The interest in ceramic materials for dental applications has gradually increased due to the unique properties of ceramics and patient demand for optimal aesthetics as well as metal free alternatives.
To evaluate the effects of spark plasma sintering (SPS) on the microstructure of lithium disilicate glass-ceramics.
IPS e.max CAD glass-ceramic samples were processed using spark plasma sintering (SPS) and conventionally sintered (CS) as a comparison. Specimens were sintered at varying temperatures (T1: 840°C, T2: 820°C, T3: 800°C), heating rates (HR1: 150°C/min, HR2: 300°C/min, HR3: 500°C/min) and pressures (P1: 15MPa, P2: 50MPa, P3: 70MPa). IPS e.max Press glass powder samples were densified at 750 and 800°C (50 or 200MPa pressure). Samples were characterized using XRD, HTXRD, and SEM and quantitative image analysis.
There was a significant increase in median crystal size (MCS) between the CS and the SPS T1 groups. A statistical difference (p>0.05) in MCS between SPS T1 and SPS T2 groups was observed. The SPS HR3 sample produced a smaller MCS than the CS, SPS HR1 and HR2 groups (p<0.05). The SPS P3 sample had a reduction in MCS compared with the CS group (p<0.05). XRD of the SPS samples revealed major lithium disilicate/lithium metasilicate phases and minor lithium orthophosphate and cristobalite/quartz phases. Densified IPS e.max Press glass samples resulted in fine fibrils or graduated lithium disilicate crystals.
The effects of SPS were used to refine the microstructure of IPS e.max CAD lithium disilicate glass-ceramics. Densification by SPS of IPS e.max Press glass resulted in textured and fine nano-crystalline microstructures. SPS generated glass-ceramic microstructures may have unique properties and could be useful in the production of CAD/CAM materials for dentistry.
Copyright © 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.
Glass has been an important material since the early stages of civilization. Glass–ceramics are polycrystalline materials obtained by controlled crystallization of certain glasses that contain one or more crystalline phases dispersed in a residual glass matrix. The distinct chemical nature of these phases and their nanostructures or microstructures have led to various unusual combinations of properties and applications in the domestic, space, defense, health, electronics , architecture, chemical, energy, and waste management fields.
Classification systems for all-ceramic materials are useful for communication and educational purposes and warrant continuous revisions and updates to incorporate new materials. This article proposes a classification system for ceramic and ceramic-like restorative materials in an attempt to systematize and include a new class of materials. This new classification system categorizes ceramic restorative materials into three families: (1) glass-matrix ceramics, (2) polycrystalline ceramics, and (3) resin-matrix ceramics. Subfamilies are described in each group along with their composition, allowing for newly developed materials to be placed into the already existing main families. The criteria used to differentiate ceramic materials are based on the phase or phases present in their chemical composition. Thus, an all-ceramic material is classified according to whether a glass-matrix phase is present (glass-matrix ceramics) or absent (polycrystalline ceramics) or whether the material contains an organic matrix highly filled with ceramic particles (resin-matrix ceramics). Also presented are the manufacturers' clinical indications for the different materials and an overview of the different fabrication methods and whether they are used as framework materials or monolithic solutions. Current developments in ceramic materials not yet available to the dental market are discussed.
In this review we critically analyze 28 theses and dissertations and over 30 scientific papers that tested Biosilicate®, a highly bioactive glass-ceramic, in a number of applications throughout the past 20 years. Biosilicate® presents a combination of positive features for bone tissue regeneration: it is highly bioactive, osteoconductive, osteoinductive, non-cytotoxic, non-genotoxic and has antibacterial properties. In addition, in the monolithic form, it is quite strong and tough. Its in vitro bioactivity is similar to that of the gold standard Bioglass 45S5. Biosilicate® has shown to be a very versatile, multipurpose biomaterial. It can be applied in powder, monolithic and 3D scaffold forms that could be easily machined during surgical procedures. This material has been successfully tested in a number of in vitro, in vivo and clinical studies, and several trials are ongoing. Biosilicate® is indeed a great option for a wide range of tissue engineering applications.
The need for implants to repair large bone defects is driving the development of porous synthetic scaffolds with the requisite mechanical strength and toughness in vivo. Recent developments in the use of design principles and novel fabrication technologies are paving the way to create synthetic scaffolds with promising potential for reconstituting bone in load-bearing sites. Here, the state of the art in the design and fabrication of bioactive glass and ceramic scaffolds that have improved mechanical properties for structural bone repair is reviewed. Scaffolds with anisotropic and periodic structures can be prepared with compressive strengths comparable to human cortical bone (100−150 MPa), while scaffolds with an isotropic structure typically have strengths in the range of trabecular bone (2−12 MPa). However, the mechanical response of bioactive glass and ceramic scaffolds in multiple loading modes such as flexure and torsion—as well as their mechanical reliability, fracture toughness, and fatigue resistance—has received little attention. Inspired by the designs of natural materials such as cortical bone and nacre, glass-ceramic and inorganic/polymer composite scaffolds created with extrinsic toughening mechanisms are showing potential for both high strength and mechanical reliability. Future research should include improved designs that provide strong scaffolds with microstructures conducive to bone ingrowth, and evaluation of these scaffolds in large animal models for eventual translation into clinical applications.
Bioactive ceramics bond directly with living tissues when implanted. For this reason they have been profusely investigated as biomaterials. The first synthetic bioactive materials were specific compositions of glasses and glass ceramics as well as sintered hydroxyapatite. However, all these bioceramics are brittle, and for this reason their main application for years has been as a grafting material for the filling of small bone defects and periodontal anomalies. The efforts to expand the applications of bioactive bioceramics were mainly focused in two areas: (A) the synthesis of organic-inorganic hybrids to apply in tissue engineering and of ceramic coatings on metallic substrates for applications requiring good mechanical behavior, and (B) the synthesis of porous materials with very quick bioactive response that can be upgraded by adding biomolecules or therapeutic inorganic ions to be used in bone tissue engineering. For these developments, the in vitro studies in solutions mimicking blood plasma played a major role. At the present, it is universally considered that both bioactive and biodegradable materials are going to play a central role in the fabrication of porous scaffolds that after being decorated with cells and signals form constructs: basic elements of tissue engineering. This article reviews the pathway followed by the bioactive materials from their original applications in bone grafts to the present day where they are widely investigated as porous scaffolds for bone tissue engineering. After defining the concept of bioactivity, important bioactive materials will be listed in this article. Then, the specific characteristics of bioactive materials when used in bulk or coatings as well as the comparison with biodegradable materials will be presented. Finally, and after describing the in vitro studies for the evaluation of bioactive ceramics, the main characteristics of template glasses, compared with conventional sol-gel glasses, and the advantages of using porous bioactive ceramics to obtain scaffolds for bone tissue engineering will be explained.
Objectives
To verify the effects of alternating thermal changes in aqueous media and chemical composition on mechanical properties of apatite–mullite glass–ceramics and to investigate concentration of ions eluted from glass–ceramics in aqueous media.
Materials and methods
The glass compositions were from SiO2Al2O3P2O5CaOTiO2BaOZrO2CaF2 system. Glass–ceramics were prepared by heat-treating at 1100 °C for 3 h samples alternately immersed in water at 5 and 60 °C. The 3-point bending strength (n = 10) were determined using 3 × 4 × 25 mm/bar and a universal testing machine, at a cross-head speed of 0.1 mm/min. Vickers micro hardness were evaluated by applying a total of 15–20 indentations under a 100 g load for 30 s. Concentrations of ions eluted from glass–ceramics immersed in 60 ± 5 °C double distilled water were determined by ion chromatography. The toxicity of glass–ceramics was assessed by seeding the osteosarcoma cells (MG63) on powder for different days and their cell proliferation assessment was investigated by MTT assay. The data were analyzed using one way analysis of variance and the means were compared by Tukey's test (5% significance level).
Results
The highest flexural strength and hardness values after thermal changes belonged to TiO2 and ZrO2 containing glass–ceramics which contained lower amount of released ions. BaO containing glass–ceramic and sample with extra amount of silica showed the highest amount of reduction in their mechanical strength values. These additives enhanced the concentration of eluted ions in aqueous media. MTT results showed that glass–ceramics were almost equivalent concerning their in-vitro biological behavior.
Significance
Thermal changes and chemical compositions had significant effects on flexural strength and Vickers micro-hardness values.
This is the second edition of the classic book An Introduction to Bioceramics which provides a comprehensive overview of all types of ceramic and glass materials that are used in medicine and dentistry. The enormous growth of the field of bioceramics is due to the recognition by the medical and dental community of the importance of bioactive materials to stimulate repair and regeneration of tissues. This edition includes 21 new chapters that document the science and especially the clinical applications of the new generation of bioceramics in the field of tissue regeneration and repair. Important socioeconomic factors influencing the economics and availability of new medical treatments are covered with updates on regulatory procedures for new biomaterials, methods for technology transfer and ethical issues. The book contains 42 chapters that offer the only comprehensive treatment of the science, technology and clinical applications of all types of bioceramic materials used in medicine and dentistry. Each chapter is written by leaders in their specialized fields and is a thorough review of the subject matter, unlike many conference proceedings. All chapters have been edited to reflect the same writing style, making the book an easy read. The completeness of treatment of all types of bioceramics and their clinical applications makes the book unique in the field and invaluable to all readers.
Glass-ceramic materials are increasingly becoming the material of choice in the field of dental prosthetics, as they can feature both high strength and very good aesthetics. It is believed that their color, microstructure and mechanical properties can be tuned such as to achieve an optimal lifelike performance. In order to reach that ultimate perfection a controlled arrangement of amorphous and crystalline phases in the material is required. A phase transformation from amorphous to crystalline is achieved by a heat treatment at defined temperature levels. The traditional approach is to perform the heat treatment in a furnace. This, however, only allows a homogeneous degree of crystallization over the whole volume of the parent glass material. Here a novel approach using a local heat treatment by laser irradiation is presented. To investigate the potential of this approach the crystallization process of SiO2-Li2O-Al2O3-based glass has been studied with laser systems (pulsed and continuous wave) operating at different wavelengths. Our results show the feasibility of gradual and partial crystallization of the base material using continuous laser irradiation. A dental prosthesis machined from an amorphous glassy state can be effectively treated with laser irradiation and crystallized within a confined region of a few millimeters starting from the body surface. Very good aesthetics have been achieved. Preliminary investigation with pulsed nanosecond lasers of a few hundreds nanoseconds pulse width has enabled more refinement of crystallization and possibility to place start of phase change within the material bulk.
In this work, the effects of partial substitution of K2O for Na2O on the sintering and crystallization of a SiO2-CaO-K2O-Na2O-CaF2 glass have been studied. This glass composition was close to the glass-forming composition of fluorocanasite miner al. T he glass-cer amics were made v ia sintering with concurr ent crystallization of glass-powder compacts. The samples were characterized by hot stage micr oscopy, dif fer ential t hermal analy sis, X- r ay diff r action and scanning electron microscopy. CaF2 precipitated as a primary crystal in all studied glasses and crystallizat ion was predominant between 625° and 1000°C . All glasses showed the best sinterability at 1000°C. By increasing the K2O content from 7 to 13 mol% (at the expense of Na2O), the crystallization peaks shifted to higher t emper at ur es and the main cr yst alline phases at t he best sintering temperature were fluorocanasite, cuspidine, xonotlite and wollastonite. Vickers microhar dness, 3- point bending str ength, f ract ure t oughness and t her mal expansion coeff icient were estimated to identif y the optimum composition. M easurements revealed that the addition of 10 mol% K 2O to the base glass improv ed t he bending st rengt h fr om 110±10 to 137±7 M Pa. T he maximum achieved fracture toughness was 2.6±0.1 M Pa.m1/2.
Fluorocanasite (Al2O3-CaO-F-K2O-Na2O-SiO2) glass-ceramics exhibit fracture toughness values of up to 5.0 MPa.m(1/2). However, their chemical durability is not adequate for dental applications. The objective of this study was to test the hypothesis that an increased concentration of Al2O3 can increase the chemical durability of fluorocanasite-based glass-ceramics. Glass frits containing 2 wt% (CAN2), 5 wt% (CAN5), and 10 wt% Al2O3 (CAN10) were melted individually, poured into a graphite mold, and cut into 16-mm-diam. x 2-mm-thick disks. Each disk was crystallized at 850 degrees C for 6 hrs. The disks were immersed in a solution of de-ionized-distilled water, 4% acetic acid, or a pH 1 buffer solution, and sealed in 90-mt Teflon containers. Corrosion testing was performed by means of vibrational motion at 60 cycles per min in a shaker-bath at 80 degrees C for 15 days. Solution analyses were performed by means of a pH meter, an atomic absorption spectrophotometer, and an inductively coupled plasma spectrometer. Samples exposed to 4% acetic acid solution exhibited a mean weight loss rate (WLR) for the control group (Dicor) of 0.04 +/- 0.01 mg/cm(2).day, which was significantly lower (p less than or equal to 0.0001) than the mean WLR of the CAN2 (1.08 +/- 0.02 mg/cm(2).day), CAN5 (1.31 +/- 0.02 mg/cm(2).day), and CAN10 (1.51 +/- 0.05 mg/cm(2).day) groups. The reduced durability of fluorocanasite-based glass-ceramics with increasing Al2O3 concentration is most likely associated with a more uniform distribution of smaller crystals during heat treatment of the glass.
Antimicrobial coatings based on a family of non-toxic, antimicrobial glass that belongs to the SiO2-Na2O–Al2O3–CaO–B2O3 system, were thermally sprayed on titanium plates by high velocity suspension flame spraying (HVSFS). Atomized glass microspheres (<10 μm) were dispersed in water in order to prepare suitable suspensions for the HVSFS process. Spraying antimicrobial atomized glass microspheres results in mechanical stable coatings with a layer thickness ∼25 μm. The process does not compromise the antimicrobial activity of the glass and it does not cause it to significantly crystallize. The coatings were proven to be antimicrobial versus Escherichia coli, Staphylococcus aureus and Candida krusei. This raises the possibility for its application on titanium-based implants, for instance in dental prosthesis, preventing at the same time infections and implant corrosion.
A machineable mica based glass-ceramic for dental application has been developed. The main crystalline phase of the product is a Na-fluorophlogopite mica. The effect of ZrO2 addition on nucleation and crystallization was studied and the resulting microstructure was compared with the mechanical properties. No effective nucleation process was found in the zirconia-free composition. A constant number of crystals was found independent of the crystallization conditions. Therefore it is assumed that nuclei are quenched in during the preparation of the glass. A linear growth law for the mica crystals was found. Pseudodendritic growth forms seem to be the consequence of lattice defects. In contrast, the nucleation process of the ZrO2-containing glass is sensible to variations in composition and nucleation temperature. An optimized nucleation leads to a fine-grained mica structure after crystallization at 900°C. The fine-grained material has the highest mechanical strength and also better machineability and translucency. A second heating step may be applied to further strengthen the material, but translucency is decreased.
Objective:
The aim of this study was to evaluate the effect of TiO2 concentration on the properties of apatite-mullite glass-ceramics namely strength and the chemical solubility to comply with the ISO standard recommendations for dental ceramics (BS EN ISO 6872-2008) [1].
Methods:
Ten novel glass-ceramic materials were produced based on the general formula (4.5SiO2-3Al2O3-1.5P2O5-3CaO-CaF2-xTiO2) where x varied from 0.5 to 5wt%. Glass with no TiO2 added (HG1T0.0) was used as a reference. Discs of 12mm diameter and 1.6mm (±0.2mm) thickness were prepared for both biaxial flexural strength (BFS) and chemical solubility testing, in accordance with the BS EN ISO 6872-2008 [1] for dental ceramics. All produced materials were investigated using differential thermal analysis (DTA), X-ray diffraction (XRD), and scanning electron microscopy (SEM). Energy dispersive X-ray analysis (EDS) was also carried out on some samples to identify the element composition of samples.
Results:
Increasing the concentration of TiO2 from 0.5wt% to 2wt% significantly (P<0.05) increased the chemical solubility of the material. With the material containing 2.5wt% of TiO2, the solubility significantly reduced (P<0.05) and resulted in a solubility value of 228.3μm/cm(2) and BFS value of 197.9MPa. Increasing the TiO2 concentration more than 2.5wt%, led to a significant (P<0.05) increase in solubility and a reduction in BFS.
Conclusions:
TiO2 is an effective agent for improving the durability and the mechanical properties of an apatite-mullite glass-ceramic only up to 2.5wt% concentration.
The interest around bioactive glass-ceramics has grown significantly over the last two decades due to their appropriate biochemical and mechanical properties. The intense research effort in this field has led to some new commercial products for biomedical applications. This review paper begins with the basic concepts of glass-ceramic processing and development via controlled heat treatments of monolithic pieces or sinter-crystallization of powdered glasses. We then go on to describe the processing, properties and applications of some commercial bioactive glass-ceramics and discuss selected valuable reported researches on several promising types of bioactive glass-ceramics. The paper finishes with a section on open relevant research directions for bioactive glass-ceramic development. This article is protected by copyright. All rights reserved.
The processing route and synthesis of glass-ceramics are briefly reviewed including crystal nucleation and crystal growth. This is followed by a review of apatite-based glass-ceramics. The apatite–wollastonite (AW) system is reviewed in terms of its crystallization behavior, physical and mechanical properties, and biological behavior. Subsequently, other types of apatite glass-ceramics are reviewed including apatite–mullite (AM) glass-ceramics. This glass-ceramic system has good mechanical properties like the AW glass-ceramics and can be cast to shape.
Ceramic materials are among the most biocompatible materials developed for dental restorations. The interest in all-ceramic restorations has rapidly increased over the past decade as stronger, tougher and more aesthetic materials are developed, along with novel processing technologies such as hot pressing and CAD/CAM (computer-aided design/computer-assisted manufacture [1]. Ceramics are widely used in dentistry because of their natural appearance and excellent mechanical, optical, thermal and chemical properties [2]. Dental ceramics exhibit many desirable material properties, including biocompatibility, chemical inertness, aesthetics, compressive strength, diminished plaque accumulation, low thermal conductivity, abrasion resistance and colour stability [2, 3]. However, the possible applications for dental all-ceramic restorations are limited due to their brittle nature, sensitivity to flaws and defects, low tensile strength and fracture toughness [4]. The presence of numerous surface and internal flaws, which may develop as a result of thermal, chemical or mechanical processes, can act as stress concentrators, reducing the strength of ceramics. These stresses can cause cracks to originate from the defect site which can propagate and lead to catastrophic failure [5]. New materials and different processing methods have been introduced in recent years in an attempt to overcome these inherent problems. This review covers the development of dental ceramics including the history, classification and description of the different types of material, fabrication technologies, and mechanical and physical properties. Emphasis is placed on how these new materials and processing methods are overcoming the aforementioned problems. Clinical trials and longevity data is covered along with preparation guidelines. The evolution of all-ceramic restorations is addressed and focus is placed on high strength core ceramics and resin bonded glass-ceramic restorations. The interest in ceramic materials for dental applications has gradually increased due to the unique properties of ceramics and patient demand for optimal aesthetics as well as metal free alternatives.
Sol-gel derived silica-based bioactive glasses and ceramics attain many advantages owing to silicon which has a beneficial role in bone formation in vivo. They exhibit mesoporous architecture with interconnected pore structure and a high specific surface area that positively affects their bioactivity. Their compositions of up to 100mol% SiO2 in binary, ternary or quaternary systems, the potential for varying the microstructure in the same composition by controlling the chemical reactions and their ability to form scaffolds are some of the unique properties that distinguish them from their melt-derived counterparts. In the field of dental restoration and regeneration, sol-gel silica-based bioactive composites have started to emerge in various applications including coatings, scaffolds and dental tissue regeneration.
Feldspathic porcelains, leucite, and lithium disilicate glass-ceramics are important materials used in restorative dentistry for their biocompatibility, excellent aesthetic properties, good mechanical strength, and relative ease of use. As a general rule in clinical practice, the choice of material should be dictated by the specific clinical situation. It depends on the space available to build the aesthetic and functional restoration, but also on the nature of the underlying tooth or restorative structure. The best aesthetic results are obtained with feldspathic porcelain restorations directly resin-bonded to the tooth, whereas the best function is obtained with the stronger and tougher fully anatomical or veneered glass-ceramic crowns and bridges. The main limitation with these ceramics is their insufficient strength for use as posterior crowns and bridges. Possible means to obtain aesthetically pleasing and long-term performing posterior restorations are the development of stronger glass-ceramics, the use of translucent colored zirconia, or the use of the new class of more elastic hybrid polymer-ceramic materials.
Dental ceramic restorations are essentially oxide based glass-ceramicsystems. Glass-ceramics are employed in medicine and dentistry because they arerelatively easy to process and have impressive mechanical properties. In addition, allceramicdental restorations are attractive for both dentists and patients because theyhave excellent aesthetics and their low thermal conductivity makes them comfortable inthe mouth. In addition, the material is extremely durable and relatively easy tomanufacture into customised units. The first ceramic to be used in dental restorationwas dental porcelain. Introduced in the 1960s, this material has shown excellentaesthetics and biocompatibility, but its strength is only adequate for a limited range ofapplications. The development of advanced dental material technologies has recentlyled to the introduction of a range of all-ceramic restorations in dentistry. In this chapter,the authors have summarised the fundamental principles of glass-ceramic technologyparticularly it's use in dentistry and also give general information about currentcommercial materials and those currently under development. Detailing their properties,processing methods and how they may affect the future of dentistry.
The use of biomaterials is increasing in treatments today and will increase further in the future. The clinical need for biomaterials in maxillofacial and oral cavity areas is both demanding and versatile. The chapter first discusses key facts and applications of traditional reconstruction materials, also offering comparative data. It then describes the properties and clinical applications of bioactive glass in maxillofacial and dental uses, and provides clinical findings.
Titanium and its alloys show the greatest biocompatibility among metallic materials for biomedical applications. They are, however, grouped within bioinert materials together with ceramics, such as alumina and zirconia, on the basis of the pattern of osteogenesis. For tight fixation and long-term use, some applications need bioactivity, which means an ability to make a bond directly to natural bone. Calcium phosphate-based ceramic materials, such as hydroxyapatite, tricalcium phosphate and so on, show bioactivity, and are often coated onto metallic biomaterials. In this chapter, some recent topics concerning bioactive ceramic coatings on metallic biomaterials are briefly reviewed. New types of coating methods on titanium and its alloys, including plasma-spraying for forming highly oriented hydroxyapatite, sputtering or vapor-deposition for inducing excellent bioactivity and phosphate glass-ceramic joining, are focused upon, as well as the chemical modifications of their surfaces.
Objective:
To investigate the effect of firing protocols on flexural strength, surface roughness, and crystalline structure of a leucite-based glass ceramic.
Methods:
Discs produced by automated machining were distributed into five groups (n=30) according to the applied firing protocols, conducted above (790°C) or below (575°C) the ceramic transition temperature (Tg) (625±20°C): C - control, no heat treatment; G790 - glaze firing (790°C) for 1.5min (manufacturer-recommended); G790-SC - G790 modified by slow cooling; EGF790-SC - extended G790 for 15min, with slow cooling; and EF575-SC - extended firing below Tg at 575°C for 15min, with slow cooling. Discs were subjected to biaxial flexural tests and results were assessed using Weibull analysis. Surface roughness was measured before and after treatments. One specimen from each group was used for X-ray diffraction (XRD).
Results:
Highest values of characteristic strength (σ0) were obtained for EGF790-SC (211.7MPa). Regimens EF575-SC, G790-SC, and G790 produced σ0 values (167.9, 157.7, and 153.7MPa, respectively) lower than the control (C) (187.7MPa). The Weibull modulus (m) was statistically similar between groups. All treatments reduced the mean roughness (Ra) of the specimens. Extended cycles (EGF790-SC, EF575-SC) decreased the mean amplitude (Rz). XRD revealed no crystalline phase transformation and slight changes in size of leucite crystallites.
Significance:
Increased values of fracture strength and decreased surface roughness for a leucite-reinforced glass ceramic are achieved by extended glaze firing after machining. Crystalline structure is not modified. Glaze cycles, manufacturer-recommended or modified by slow cooling, and firing below Tg, significantly reduce fracture strength.
One of the major goals of bone tissue engineering is the development of appropriate porous biomaterials (scaffolds) that can stimulate the body's own regenerative mechanism, to induce tissue healing and self-repair. Bioactive glasses are excellent candidates for producing 3-D scaffolds, as their properties can be finely tailored depending on the glass composition, and they can bond to bone, inducing osteogenesis at the defect site. This chapter is focused on glass/glass-ceramic scaffolds characterized by foam-like architecture closely mimicking that of natural cancellous bone. After giving an overview of the features and limitations of the biomedical glass foams investigated in the literature, future directions of research will be described, emphasizing the challenge to develop multifunctional foams able to combine bone regeneration with special therapeutic functionalities.
Melt-derived bioactive glasses and glass-ceramics are class A bioactive materials, exhibiting surface bioreactivity in contact with physiological fluids, making them significant in developing bone tissue engineering (BTE) scaffolds. Their biological performance relates to the effect of released ionic dissolution products on osteogenesis and angiogenesis. This chapter discusses the fabrication of three-dimensional, highly porous bioactive glass scaffolds for BTE using the foam replica technique, considering two types of scaffolds in detail: BTE scaffolds fabricated from boron-containing bioactive glass and polymer coated scaffolds of enhanced mechanical behavior, adequate bioactivity and potential drug delivery capability. The presence of a polymer coating leads to significant toughening, and the polymer phase can be used to act as a carrier for biomolecules, growth factors and antibiotics. Optimization of BTE scaffolds is key to the advancement of BTE, and the utilization of bioactive glasses as suitable vehicles for the controlled release of certain metallic ions, which stimulate specific cellular responses, is highlighted as important for future research. New compositions of silicate bioactive glasses incorporating determined therapeutic ions, combined with biopolymers, will become significant in BTE as materials of choice for scaffold developments.
The process of drying of a porous material can be divided into several stages. At first, the body shrinks by an amount equal to the volume of liquid that evaporates and the liquid-vapor interface remains at the exterior surface of the body. The second stage begins when the body becomes too stiff to shrink and the liquid recedes into the interior, leaving air-filled pores near the surface. Even as air invades the pores, a continuous liquid film supports flow to the exterior, so evaporation continues to occur from the surface of the body. Eventually, the liquid becomes isolated into pockets and drying can proceed only by evaporation of the liquid within the body and diffusion of the vapor to the outside. This chapter discusses the transport processes acting during these stages. It also discusses the factors affecting stress development and various strategies for avoiding warping and cracking.
Nano-Glass Ceramics: Processing, Properties and Applications provides comprehensive coverage of synthesis and processing methods, properties and applications of the most important types of nano-glass ceramics, from a unique material science perspective. Emphasis is placed on the experimental and practical aspects of the subject while covering the theoretical and practical aspects and presenting, numerous examples and details of experimental methods. In the discussing the many varied applications of nano-glass ceramics, consideration is given to both, the fields of applications in which the materials are firmly established and the fields where great promise exists for their future exploitation. The methods of investigation adopted by researchers in the various stages of synthesis, nucleation, processing and characterization of glass ceramics are discussed with a focus on the more novel methods and the state of the art in developing nanostructured glass ceramics. Comprehensive coverage of nanostructured glass ceramics with a materials science approach. The first book of this kind Applications-oriented approach, covering current and future applications in numerous fields such as Biomedicine and Electronics Explains the correlations between synthesis parameters, properties and applications guiding R&D researchers and engineers to choose the right material and increase cost-effectiveness.
Master the use of dental materials in the clinic and dental laboratory and stay current with this ever-changing field with Craigs Restorative Dental Materials, 13th Edition. From fundamental concepts to advanced skills, this comprehensive text details everything you need to know to understand the scientific basis for selecting dental materials when designing and fabricating restorations. This practical, clinically relevant approach to the selection and use of dental materials challenges you to retain and apply your knowledge to realistic clinical scenarios, giving you an authoritative advantage in dental practice.
To verify the effects of alternating thermal changes in aqueous media and chemical composition on mechanical properties of apatite-mullite glass-ceramics and to investigate concentration of ions eluted from glass-ceramics in aqueous media.
The glass compositions were from SiO2Al2O3P2O5CaOTiO2BaOZrO2CaF2 system. Glass-ceramics were prepared by heat-treating at 1100°C for 3h samples alternately immersed in water at 5 and 60°C. The 3-point bending strength (n=10) were determined using 3×4×25mm/bar and a universal testing machine, at a cross-head speed of 0.1mm/min. Vickers micro hardness were evaluated by applying a total of 15-20 indentations under a 100g load for 30s. Concentrations of ions eluted from glass-ceramics immersed in 60±5°C double distilled water were determined by ion chromatography. The toxicity of glass-ceramics was assessed by seeding the osteosarcoma cells (MG63) on powder for different days and their cell proliferation assessment was investigated by MTT assay. The data were analyzed using one way analysis of variance and the means were compared by Tukey's test (5% significance level).
The highest flexural strength and hardness values after thermal changes belonged to TiO2 and ZrO2 containing glass-ceramics which contained lower amount of released ions. BaO containing glass-ceramic and sample with extra amount of silica showed the highest amount of reduction in their mechanical strength values. These additives enhanced the concentration of eluted ions in aqueous media. MTT results showed that glass-ceramics were almost equivalent concerning their in-vitro biological behavior.
Thermal changes and chemical compositions had significant effects on flexural strength and Vickers micro-hardness values.
Copyright © 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.
IntroductionEnamelingGlazingPlasma SprayingRadiofrequency Magnetron Sputtering DepositionPulsed Laser DepositionSummaryReferences
Elucidating the microstructural responses of the lithium disilicate system like the popular IPS e.max® CAD (LS2), made specifically for computer-aided design and computer-aided manufacturing (CAD-CAM), as a temperature-dependent system unravels new ways to enhance material properties and performance.
To study the effect of various thermal processing on the crystallization kinetics, crystallite microstructure, and strength of LS2.
The control group of the LS2 samples was heated using the standard manufacturer heating-schedule. Two experimental groups were tested: (1) an extended temperature range (750-840°C vs. 820-840°C) at the segment of 30°C/min heating rate, and (2) a protracted holding time (14min vs. 7min) at the isothermal temperature of 840°C. Five other groups of different heating schedules with lower-targeted temperatures were evaluated to investigate the microstructural changes. For each group, the crystalline phases and morphologies were measured by X-ray diffraction (XRD) and scanning electron microscope (SEM), respectively. Differential scanning calorimeter (DSC) was used to determine the activation energy of LS2 under non-isothermal conditions. A universal testing machine was used to measure 3-point flexural strength and fracture toughness, and elastic modulus and hardness were measured by a nanoindenter. A one-way ANOVA/Tukey was performed per property (alpha=0.05).
DSC, XRD, and SEM revealed three distinct microstructures during LS2 crystallization. Significant differences were found between the control group, the two aforementioned experimental groups, and the five lower-targeted-temperature groups per property (p<0.05). The activation energy for lithium disilicate growth was 667 (±29.0)kJ/mol.
Groups with the extended temperature range (750-840°C) and protracted holding time (820-840°C H14) produced significantly higher elastic-modulus and hardness properties than the control group but showed similar flexural-strength and fracture-toughness properties with the control group. In general, rapid growth of lithium disilicates occurred only when maximum formation of lithium metasilicates had ended.
Published by Elsevier Ltd.
gel synthesis, structure, sintering and properties of bioactive and inert nano apatite-zirconia glass-ceramics, Ceramics International, http://dx.
The objective of this paper is to highlight the ten most important milestones of publications that led from the concept of bioactive bonding of tissues towards eventual clinical applications. This is the first paper to describe the bonding of living bone to a man-made material, a special composition range of soda-calciaphospho-silicate glasses and glass-ceramics that have become known as bioactive glasses or for a specific composition, 45S5 Bioglass. A mechanism of chemical bonding of bone to the bioactive glass material is also described in this seminal paper.
Objectives:
To produce a new veneering ceramic based on the production of a multiple phase glass-ceramic with improved performance in terms of strength and toughness.
Methods:
A composition of 60% leucite, 20% diopside and 20% feldspathic glass was prepared, blended and a heat treatment schedule of 930°C for 5 min was derived from differential thermal analysis (DTA) of the glasses. X-ray diffraction (XRD) and SEM analysis determined the crystalline phases and microstructure. Chemical solubility, biaxial flexural strength (BFS), fracture toughness, hardness, total transmittance and coefficient of thermal expansion (CTE) were all measured in comparison to a commercial veneering ceramic (VITA VM9). Thermal shock resistance of the leucite-diopside and VITA VM9 veneered onto a commercial high strength zirconia (Vita In-Ceram YZ) was also assessed. Statistical analysis was undertaken using Independent Samples t-test. Weibull analysis was employed to examine the reliability of the strength data.
Results:
The mean chemical solubility was 6 μg/cm(2) for both ceramics (P=1.00). The mean BFS was 109 ± 8 MPa for leucite-diopside ceramic and 79 ± 11 MPa for VITA VM9 ceramic (P=0.01). Similarly, the leucite-diopside ceramic demonstrated a significantly higher fracture toughness and hardness. The average total transmittance was 46.3% for leucite-diopside ceramic and 39.8% for VITA VM9 (P=0.01). The leucite-diopside outperformed the VITA VM9 in terms of thermal shock resistance. Significance This novel veneering ceramic exhibits significant improvements in terms of mechanical properties, yet retains a high translucency and is the most appropriate choice as a veneering ceramic for a zirconia base core material.
Two important worldwide needs must be satisfied in the future; (1) treatment of the deteriorating health of an aging population and, (2) decreasing healthcare costs to meet the needs of an increased population. The ethical and economic dilemma is how to achieve equality in quality of care while at the same time decreasing cost of care for an ever-expanding number of people. The limited lifetime of prosthetic devices made from first-generation nearly inert biomaterials requires new approaches to meet these two large needs. This paper advises an expanded emphasis on: (1) regeneration of tissues and (2) prevention of tissue deterioration to meet this growing need. Innovative use of bioactive ceramics with genetic control of in situ tissue responses offers the potential to achieve both tissue regeneration and prevention. Clinical success of use of bioactive glass for bone regeneration is evidence that this concept works. Likewise the use of micron sized bioactive glass powders in a dentifrice for re-mineralization of teeth provides evidence that prevention of tissue deterioration is also possible. This opinion paper outlines clinical needs that could be met by innovative use of bioactive glasses and ceramics in the near future; including: regeneration of skeletal tissues that is patient specific and genetic based, load-bearing bioactive glass-ceramics for skeletal and ligament and tendon repair, repair and regeneration of soft tissues, and rapid low-cost analysis of human cell-biomaterial interactions leading to patient specific diagnoses and treatments using molecularly tailored bioceramics.
Titanium dental implants have a high success rate; however, there are instances when a modified surface may be desirable. The aim of this article was to systematically review the different types of implant coatings that have been studied clinically, in vivo and in vitro, and the coating techniques being implemented.
The literature was searched electronically and manually through The Cochrane Library, Medline, and PubMed databases to identify articles studying dental implant surfaces and coating techniques. The database search strategy revealed 320 articles, of which 52 articles were considered eligible-40 in relation to implant coatings and 12 to the coating technique. An additional 30 articles were retrieved by hand search.
Several materials were identified as possible candidates for dental implant coatings; these include carbon, bisphosphonates, bone stimulating factors, bioactive glass and bioactive ceramics, fluoride, hydroxyapatite (HA) and calcium phosphate, and titanium/titanium nitride. HA coatings still remain the most biocompatible coatings even though the more innovative bioglass suggests promising results. The most common coating techniques are plasma spraying and hydrocoating. More recent techniques such as the nanoscale technology are also discussed.
Several implant coatings have been proposed, and some appear to give better clinical results and improved properties than others. Clinical trials are still required to provide compelling evidence-based results for their long-term successful outcomes.