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Dental and Medical Problems 2018New glass-ceramic restorative materials have been developed over the last few years, with enhanced strength characteristics along with desirable optical properties that... (Review)
Review
New glass-ceramic restorative materials have been developed over the last few years, with enhanced strength characteristics along with desirable optical properties that make them ideal for the fabrication of esthetic crowns and veneers. The purpose of this paper was to provide an overview of the current state of the art of porcelain veneers as a viable option for the esthetic treatment of anterior teeth, and to illustrate the potential of the newly-developed glass-ceramics. Some historical background about the development of the porcelain veneer concept is provided. A list of indications and contraindications for porcelain veneers is followed by their preparation designs, with emphasis on the importance of maintaining the preparation boundaries within the enamel. Impression-taking procedures, provisional restoration fabrication, the choice of porcelain materials and their intaglio surface treatment are all discussed. A case where veneers made with a lithium-disilicate glass-ceramic were used to improve the appearance of maxillary anterior teeth is included. Several studies reporting on the longevity of porcelain veneers up to 12 years are discussed.
Topics: Acid Etching, Dental; Ceramics; Dental Impression Technique; Dental Porcelain; Dental Restoration Failure; Dental Veneers; Humans
PubMed: 30152626
DOI: 10.17219/dmp/90729 -
Dental Clinics of North America Oct 2017A survey of the development of dental ceramics is presented to provide a better understanding of the rationale behind the development and clinical indications of each... (Review)
Review
A survey of the development of dental ceramics is presented to provide a better understanding of the rationale behind the development and clinical indications of each class of ceramic material. Knowledge of the composition, microstructure, and properties of a material is critical for selecting the right material for specific applications. The key to successful ceramic restorations rests on material selection, manufacturing technique, and restoration design, including the balancing of several factors such as residual stresses, tooth contact conditions, tooth size and shape, elastic modulus of the adhesives and tooth structure, and surface state.
Topics: Ceramics; Dental Porcelain; Dental Restoration, Permanent; Dental Veneers; Humans; Metal Ceramic Alloys
PubMed: 28886769
DOI: 10.1016/j.cden.2017.06.005 -
Clinical and Experimental Dental... Dec 2022This systematic review aims to investigate the effect of different preparation designs on the marginal fit and fracture strength of ceramic occlusal veneers. (Review)
Review
OBJECTIVES
This systematic review aims to investigate the effect of different preparation designs on the marginal fit and fracture strength of ceramic occlusal veneers.
MATERIALS AND METHODS
Based on the PICO question and the search terms, an electronic search was performed in Google Scholar, PubMed (MEDLINE), Scopus, Cochrane Library, Web of Science, Science Direct, Wiley, Ovid, and SAGE for articles published up to July 2022. After including English in vitro studies that evaluated posterior ceramic occlusal overlays at the posterior with ceramic restorations by following the PRISMA statement, the extracted data was tabulated. The methodological quality of the included studies was evaluated. Risk of bias assessment was done independently by two authors using the modified MINORS scale.
RESULTS
About 3138 search results were screened, of which 22 were selected due to their titles. Twenty-one full-text articles were assessed for eligibility. Seventeen in-vitro studies were finalized for the extraction of quantitative data. All 17 articles had a low risk of bias and were retained. The influencing items for evaluating the research were different in most studies; therefore, qualitative synthesis of the results was feasible. They generally included preparation design, material thickness, depth of preparation in the tooth, internal divergence angle, and finish line. Meta-analysis was not done due to heterogeneity of preparation types and evaluation methods. Results revealed that fracture resistance of occlusal veneers is higher than normal mastication force, and it is sufficient to prepare the occlusal surface, use a self-etching primer for bonding, and an acceptable minimum ceramic thickness. The marginal discrepancy of occlusal veneers is clinically acceptable. However, this systematic review faces some limitations due to the lack of in vivo studies, different preparation designs in included studies, different follow-ups, and lack of comprehensive explanations in articles.
CONCLUSIONS
The preparation design of occlusal veneers influences both marginal adaptation and fracture resistance. Various preparation designs are proven to have clinically acceptable fracture strength and marginal adaptation.
Topics: Dental Porcelain; Dental Veneers; Flexural Strength; Dental Stress Analysis; Materials Testing; Ceramics
PubMed: 36062841
DOI: 10.1002/cre2.653 -
Clinical and Experimental Dental... Dec 2022Tooth enamel has opalescence and fluorescence, which should be mimicked by esthetic dental restorations. The purpose of this study was to compare the effects of glazing...
OBJECTIVE
Tooth enamel has opalescence and fluorescence, which should be mimicked by esthetic dental restorations. The purpose of this study was to compare the effects of glazing and polishing on the opalescence and fluorescence of dental ceramics.
MATERIALS AND METHODS
Twenty-four discs were fabricated of feldspathic, IPS e.max, zirconia, and Enamic ceramics with 10 mm diameter and 0.5 and 1 mm thicknesses (n = 12). Of the discs fabricated with 0.5 and 1 mm thicknesses, half of them were glazed and the remaining half were polished (n = 6). Opalescence was calculated as the difference in yellow-blue (CIE ∆b*) and red-green (CIE ∆a*) color axes between the transmitted and reflected colors. The fluorescence of specimens was measured by a novel technique. Data were analyzed using two-way analysis of variance at a 0.05 level of significance.
RESULTS
In all groups (except for the Enamic ceramic), the mean opalescence of polished specimens (e.max = 2.704, feldspathic = 1.67, zirconia = 3.143) was higher than that of glazed specimens (e.max = 2.163, feldspathic = 1.016, zirconia = 2.690). The mean opalescence of glazed Enamic specimens (2.140) was higher than that of polished specimens (1.308). The fluorescence of glazed and polished specimens was not significantly different.
CONCLUSION
Surface treatment (glazing/polishing) affects the opalescence, but not the fluorescence of dental ceramics evaluated in this study.
Topics: Dental Polishing; Dental Porcelain; Iridescence; Surface Properties; Materials Testing; Ceramics
PubMed: 36245303
DOI: 10.1002/cre2.669 -
Journal (Canadian Dental Association) Sep 1998Dental porcelain has found an increased number of applications in recent years with the development of new methods for the construction of porcelain veneers and... (Review)
Review
BACKGROUND
Dental porcelain has found an increased number of applications in recent years with the development of new methods for the construction of porcelain veneers and intracoronal restorations. In addition, it is used in metal-ceramic and all-porcelain crowns and bridges for the restoration of anterior and posterior teeth.
METHODS
This paper presents a review of a number of studies that have examined the visual and microscopic appearance and roughness of glazed, unglazed and polished porcelain surfaces using techniques such as, scanning electron microscopy and surface profilometry.
FINDINGS
All have agreed that glazed porcelain provides a smooth and dense surface. Many have shown that polishing can produce an equally smooth surface, which may even be esthetically better. Some studies supported the use of polishing as an alternative to glazing. However, reports have shown that unglazed porcelain is more abrasive than glazed.
CLINICAL SIGNIFICANCE
This paper aims to guide general practitioners in the proper polishing of adjusted porcelain in the dental office. The recommendations of various authors are summarized in Table I.
Topics: Crowns; Dental Polishing; Dental Porcelain; Dental Veneers; Denture, Partial; Esthetics, Dental; Hot Temperature; Humans; Inlays; Metal Ceramic Alloys; Microscopy, Electron, Scanning; Surface Properties; Tooth Abrasion
PubMed: 9785688
DOI: No ID Found -
Dental Materials Journal Jan 2020This review describes low temperature degradation (LTD), discoloration, and erosion of high translucent dental zirconia and discusses its chemical durability in... (Review)
Review
This review describes low temperature degradation (LTD), discoloration, and erosion of high translucent dental zirconia and discusses its chemical durability in comparison with other CAD/CAM materials. The LTD of zirconia strongly depended on the firing temperature, yttria content, surface treatment, and heat treatment. Glass ceramics for CAD/CAM were remarkably etched in a lactic acid at 60°C, KOH solution at 60°C, and saline solution at 90°C, whereas zirconia showed no changes in these solutions. Glass ceramics and hybrid resins for CAD/CAM showed significant discoloration in a red wine and rhodamine B solution at 37°C, whereas zirconia showed no discolorations in either solution. It was concluded that high translucent dental zirconia has the highest chemical durability among dental CAD/CAM materials.
Topics: Ceramics; Computer-Aided Design; Dental Materials; Dental Porcelain; Materials Testing; Surface Properties; Zirconium
PubMed: 31511477
DOI: 10.4012/dmj.2019-109 -
Dental Materials : Official Publication... Mar 2016To quantify the splitting resistance of monolithic zirconia, lithium disilicate and nanoparticle-composite dental crowns.
OBJECTIVE
To quantify the splitting resistance of monolithic zirconia, lithium disilicate and nanoparticle-composite dental crowns.
METHODS
Fracture experiments were conducted on anatomically-correct monolithic crown structures cemented to standard dental composite dies, by axial loading of a hard sphere placed between the cusps. The structures were observed in situ during fracture testing, and critical loads to split the structures were measured. Extended finite element modeling (XFEM), with provision for step-by-step extension of embedded cracks, was employed to simulate full failure evolution.
RESULTS
Experimental measurements and XFEM predictions were self-consistent within data scatter. In conjunction with a fracture mechanics equation for critical splitting load, the data were used to predict load-sustaining capacity for crowns on actual dentin substrates and for loading with a sphere of different size. Stages of crack propagation within the crown and support substrate were quantified. Zirconia crowns showed the highest fracture loads, lithium disilicate intermediate, and dental nanocomposite lowest. Dental nanocomposite crowns have comparable fracture resistance to natural enamel.
SIGNIFICANCE
The results confirm that monolithic crowns are able to sustain high bite forces. The analysis indicates what material and geometrical properties are important in optimizing crown performance and longevity.
Topics: Bite Force; Composite Resins; Computer-Aided Design; Crowns; Dental Porcelain; Dental Stress Analysis; Finite Element Analysis; Materials Testing; Stress, Mechanical; Zirconium
PubMed: 26792623
DOI: 10.1016/j.dental.2015.12.010 -
Journal of Oral Science Apr 2022The purpose of this study is to clarify the porcelain firing temperature conditions that give strongest bonding strength of porcelain to zirconia to manufacture...
PURPOSE
The purpose of this study is to clarify the porcelain firing temperature conditions that give strongest bonding strength of porcelain to zirconia to manufacture all-ceramic fixed dental prostheses (FDPs) with excellent long-term stability.
METHODS
Opaque porcelain samples (8.0 × 3.0 × 1.2 mm) were placed in the center of zirconia plates (25.0 × 3.0 × 0.5 mm) and fired at temperatures of 950°C, 1,050°C, 1,100°C, and 1,150°C. Schwickerath crack initiation tests, elemental analyses, and morphological changes of the samples were compared.
RESULTS
There was no difference in the bonding strength among all the groups of porcelain fired at different temperatures. Elemental analysis of Si and O at the interface between the zirconia and porcelain were observed in the 950°C, 1,050°C, and 1,100°C groups. No silicon was found in the 1,150°C group by elemental analysis, and the zirconia plate where the porcelain sample was placed had irregular shape changes.
CONCLUSION
It is suggested that silicon is also involved in chemical bonds due to firing at high temperatures.
Topics: Dental Bonding; Dental Porcelain; Dental Stress Analysis; Dental Veneers; Materials Testing; Surface Properties; Temperature; Zirconium
PubMed: 35197417
DOI: 10.2334/josnusd.21-0431 -
Dental Materials : Official Publication... May 2024Lithium silicate-based glass ceramics have evolved as a paramount restorative material in restorative and prosthetic dentistry, exhibiting outstanding esthetic and... (Review)
Review
OBJECTIVES
Lithium silicate-based glass ceramics have evolved as a paramount restorative material in restorative and prosthetic dentistry, exhibiting outstanding esthetic and mechanical performance. Along with subtractive machining techniques, this material class has conquered the market and satisfied the patients' needs for a long-lasting, excellent, and metal-free alternative for single tooth replacements and even smaller bridgework. Despite the popularity, not much is known about the material chemistry, microstructure and terminal behaviour.
METHODS
This article combines a set of own experimental data with extensive review of data from literature and other resources. Starting at manufacturer claims on unique selling propositions, properties, and microstructural features, the aim is to validate those claims, based on glass science. Deep knowledge is mandatory for understanding the microstructure evolution during the glass ceramic process.
RESULTS
Fundamental glass characteristics have been addressed, leading to formation of time-temperature-transformation (TTT) diagrams, which are the basis for kinetic description of the glass ceramic process. Nucleation and crystallization kinetics are outlined in this contribution as well as analytical methods to describe the crystalline fraction and composition qualitatively and quantitatively. In relation to microstructure, the mechanical performance of lithium silicate-based glass ceramics has been investigated with focus on fracture strength versus fracture toughness as relevant clinical predictors.
CONCLUSION
Fracture toughness has been found to be a stronger link to initially outlined manufacturer claims, and to more precisely match ISO recommendations for clinical indications.
Topics: Ceramics; Silicates; Materials Testing; Glass; Surface Properties; Dental Materials; Crystallization; Lithium Compounds; Dental Porcelain
PubMed: 38580561
DOI: 10.1016/j.dental.2024.03.006 -
Indian Journal of Dental Research :... 2022Porcelain combined with zirconia core substructure has low fracture toughness. Nanoparticles are incorporated into the porcelain to boost its mechanical properties.
BACKGROUND
Porcelain combined with zirconia core substructure has low fracture toughness. Nanoparticles are incorporated into the porcelain to boost its mechanical properties.
AIMS
To evaluate the effect of the incorporation of silver oxide and titanium oxide nanoparticles into porcelain powder on the bond strength of porcelain veneer to zirconia core. The flexural strength of nanoparticles-modified porcelain was also evaluated.
MATERIALS AND METHODS
The flexural strength of feldspathic porcelain was measured (according to ISO specifications number 6872) after the incorporation of silver and titanium oxide nanoparticles. For measuring the bond strength at the porcelain-zirconia interface, 70 bars (4 × 4 × 12 mm) of zirconia were cut and fired in a furnace. The control and nanoparticles-modified porcelain powders were built up on the zirconia bars and fired to create veneers of 3 mm height, 4 mm width and 4 mm thickness. The porcelain veneers were de-attached from the zirconia core by the universal testing machine. The failure load was recorded to calculate the bond strength.
STATISTICAL ANALYSIS
The data were analysed with one-way analysis of variance followed by Tukey's test.
RESULTS
The addition of 0.5-1.5% silver oxide nanoparticles to feldspathic porcelain increased the flexural strength. The addition of 1.0-4.0% titanium oxide nanoparticles to feldspathic porcelain increased the flexural strength. Either 0.5-1.0% silver oxide or 3.0-4.0% titanium oxide nanoparticles in feldspathic porcelain increased the shear bond strength to zirconia core.
CONCLUSION
The flexural strength of porcelain veneer and the bond strength at porcelain-zirconia interface can be improved by adding either 0.5% silver oxide nanoparticles or 4% titanium oxide nanoparticles to porcelain powder.
Topics: Dental Bonding; Dental Materials; Dental Porcelain; Dental Stress Analysis; Dental Veneers; Materials Testing; Nanoparticles; Oxides; Powders; Shear Strength; Silver Compounds; Surface Properties; Titanium; Zirconium
PubMed: 36254959
DOI: 10.4103/ijdr.ijdr_222_22