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European Journal of Dentistry Oct 2023This article evaluates the effect of multipurpose polishing kit on surface roughness and hardness of three computer-aided design/computer-aided manufacturing...
OBJECTIVE
This article evaluates the effect of multipurpose polishing kit on surface roughness and hardness of three computer-aided design/computer-aided manufacturing (CAD/CAM) ceramic materials at different polishing durations. Weight changes of the polishing bur were also determined.
MATERIAL AND METHODS
Three CAD/CAM ceramic materials were lithium disilicate glass ceramic (IPS e.max CAD), translucent zirconia (VITA YZ), and zirconia-reinforced lithium disilicate ceramic (Celtra Duo). Ceramics were ground with a diamond bur, and polished with the multipurpose polishing kit (Eve Diacera HP), which comprises coarse and fine polishing burs. Surface roughness value (Ra) was measured using a noncontact optical profilometer ( = 10 per group) after grinding and every 15 seconds of coarse and fine polishing until 60 seconds. The complete polishing Ra was compared with the lab as-received specimens and human enamel. Surface morphology was examined using a scanning electron microscope after 60-second coarse and fine polishing and compared with the lab as-received specimens. Hardness was measured using a Vickers hardness tester on the lab as-received specimens and after the final polishing process ( = 4 per group). Changes in surface roughness and polishing bur weight of each material were analyzed using one-way repeated-measures analysis of variance (ANOVA) and dependent -test. One-way ANOVA was used to detect differences in surface roughness, Vickers hardness, and bur weight among materials within the same polishing duration ( = 0.05).
RESULTS
From grinding to complete polishing, the greatest Ra reduction was found in VITA YZ, followed by Celtra Duo and IPS e.max CAD. Final Ra values of all ceramics after 60-second fine polishing were not significantly different, and were similar to that of enamel and lab as-received specimens. Vickers hardness of ceramic materials did not change after grinding and polishing. Coarse polishing bur demonstrated the highest weight loss after polishing VITA YZ, followed by Celtra Duo and IPS e.max CAD.
CONCLUSION
The multipurpose polishing kit reduced surface roughness of CAD/CAM ceramic materials to the similar level of the lab as-received specimen and enamel regardless of material's hardness. The reductions of surface roughness and a coarse polishing bur weight were highest in VITA YZ, followed by Celtra Duo and IPS e.max CAD.
PubMed: 36513337
DOI: 10.1055/s-0042-1758065 -
Cureus Nov 2023Calcium silicate-based types of cement have gained recognition in various dental applications due to their exceptional sealing capabilities, bioactivity, and minimal...
INTRODUCTION
Calcium silicate-based types of cement have gained recognition in various dental applications due to their exceptional sealing capabilities, bioactivity, and minimal adaptability. However, these materials have certain shortcomings that can lead to mechanical failures and premature degradation. The inclusion of metal ions into their structure is expected to promote their biological activity. This article focuses on the preparation and characterization of calcium silicate cement to enhance its fundamental material properties, by introducing zinc and silver while retaining its biomaterial characteristics.
AIM
This study aims to evaluate the biomedical potential of zinc and silver-impregnated bioactive calcium silicate cement.
MATERIALS AND METHODS
The calcium silicate powder was synthesized via the sol-gel method. Tetraethyl orthosilicate, calcium nitrate, silver nitrate, and zinc nitrate were sequentially added to create the bioactive calcium silicate material. The synthesized particles underwent physicochemical characterization using techniques such as scanning electron microscopy, X-ray diffraction, Raman spectroscopy, and biological characterization through in vitro hemocompatibility assays.
RESULTS
The study's results revealed the presence of multiple crystalline phases (AgSiO, ZnSiO, CaCO) as indicated by X-ray diffraction. Raman spectra displayed vibrations associated with Si-O-Si and Zn-O bonding in the zinc and silver-infused bioactive calcium silicate. Scanning electron microscopy confirmed a mixture of spherical and sheet-like morphologies, while energy dispersive spectra confirmed the presence of elements Ca, Si, Zn, Ag, O, and C. In vitro hemocompatibility testing affirmed the material's biocompatible nature.
CONCLUSION
In conclusion, the zinc and silver-infused calcium silicate cement was successfully synthesized through an in-house procedure and demonstrated biocompatibility. The inclusion of zinc and silver, known for their osteogenic and antimicrobial properties, is anticipated to enhance the cement's biological properties and broaden its utility in dentistry. Further in vitro and in vivo investigations are imperative to validate its clinical applications and elucidate the molecular mechanisms underlying its efficacy.
PubMed: 38054157
DOI: 10.7759/cureus.48243 -
Materials (Basel, Switzerland) May 2021Biomaterials and their applications are perhaps among the most dynamic areas of research within the field of biomedicine. Any advance in this topic translates to an... (Review)
Review
Biomaterials and their applications are perhaps among the most dynamic areas of research within the field of biomedicine. Any advance in this topic translates to an improved quality of life for recipient patients. One application of a biomaterial is the repair of an abdominal wall defect whether congenital or acquired. In the great majority of cases requiring surgery, the defect takes the form of a hernia. Over the past few years, biomaterials designed with this purpose in mind have been gradually evolving in parallel with new developments in the different surgical techniques. In consequence, the classic polymer prosthetic materials have been the starting point for structural modifications or new prototypes that have always strived to accommodate patients' needs. This evolving process has pursued both improvements in the wound repair process depending on the implant interface in the host and in the material's mechanical properties at the repair site. This last factor is important considering that this site-the abdominal wall-is a dynamic structure subjected to considerable mechanical demands. This review aims to provide a narrative overview of the different biomaterials that have been gradually introduced over the years, along with their modifications as new surgical techniques have unfolded.
PubMed: 34073902
DOI: 10.3390/ma14112790 -
Materials (Basel, Switzerland) Dec 2020The pulsed high power microwave (HPM) technology has been developed worldwide for over 20 years. The sources of HPM pulses are a weapon of mass destruction. They pose... (Review)
Review
The pulsed high power microwave (HPM) technology has been developed worldwide for over 20 years. The sources of HPM pulses are a weapon of mass destruction. They pose danger especially to computer and telecommunications equipment and systems, both the military and civilian ones. This paper presents a survey of literature on electromagnetic wave radiation absorbing and shielding materials to be used in construction. Relevant protective measures should include the shielding of buildings or their parts and the absorption of radiation by building envelopes and their elements. The main focus is on the possibilities of improving the shielding and absorptive properties of common construction materials, such as concrete, mortars and synthetic resins. The survey covers the following groups of materials: carbon-based admixtures, nickel powder, iron powders, ferrites, magnetite and polymers. The final part of the survey is devoted to hybrid foam microwave absorbers in which the shape of the material's inner structure and that of its surface play a special role.
PubMed: 33287143
DOI: 10.3390/ma13235509 -
Materials (Basel, Switzerland) Nov 2022In this paper, an annular/circular plate made of hyperelastic material and considering the viscoelastic property was investigated based on a novel nonlinear elasticity...
In this paper, an annular/circular plate made of hyperelastic material and considering the viscoelastic property was investigated based on a novel nonlinear elasticity theory. A new approach for hyperelastic materials in conjunction with the Kelvin-Voigt scheme is employed to obtain the structure's large deformation under uniform transverse loading. The constitutive equations were extracted using the energy method. The derived partial differential time-dependent equations have been solved via the semi-analytical polynomial method (SAPM). The obtained results have been validated by ABAQUS software and the available paper. In consequence, a good agreement between the results was observed. Finally, several affecting parameters on the analysis have been attended to and studied, such as the nonlinear elasticity analysis, the boundary conditions, loading, and the material's viscosity. It can be possible to obtain the needed time for achieving the final deformation of the structure based on the applied analysis in this research.
PubMed: 36499921
DOI: 10.3390/ma15238425 -
PloS One 2022The identification of ancient worked materials is one of the fundamental goals of lithic use wear analysis and one of the most important parts of understanding how stone...
The identification of ancient worked materials is one of the fundamental goals of lithic use wear analysis and one of the most important parts of understanding how stone tools were used in the past. Given the documented overlaps in wear patterns generated by different materials, it is imperative to understand how individual materials' mechanical properties might influence wear formation. Because isolating physical parameters and measuring their change is necessary for such an endeavor, controlled (rather than replicative) experiments combined with objective measurements of surface topography are necessary to better grasp how surface modifications formed on stone tools. Therefore, we used a tribometer to wear natural flint surfaces against five materials (bone, antler, beech wood, spruce wood, and ivory) under the same force, and speed, over one, three, and five hours. The study aimed to test if there is a correlation between surface modifications and the hardness of the worked material. We measured each raw material's hardness using a nano-indentation test, and we compared the surface texture of the flint bits using a 3D optical profilometer. The interfacial detritus powder was analyzed with a scanning electron microscope to look for abraded flint particles. We demonstrate that, contrary to expectation, softer materials, such as wood, create a smoother surface than hard ones, such as ivory.
Topics: Materials Testing; Hardness; Surface Properties; Powders; Mechanical Phenomena
PubMed: 36264949
DOI: 10.1371/journal.pone.0276166 -
Journal of Cheminformatics May 2021For photovoltaic materials, properties such as band gap [Formula: see text] are critical indicators of the material's suitability to perform a desired function....
For photovoltaic materials, properties such as band gap [Formula: see text] are critical indicators of the material's suitability to perform a desired function. Calculating [Formula: see text] is often performed using Density Functional Theory (DFT) methods, although more accurate calculation are performed using methods such as the GW approximation. DFT software often used to compute electronic properties includes applications such as VASP, CRYSTAL, CASTEP or Quantum Espresso. Depending on the unit cell size and symmetry of the material, these calculations can be computationally expensive. In this study, we present a new machine learning platform for the accurate prediction of properties such as [Formula: see text] of a wide range of materials.
PubMed: 34044889
DOI: 10.1186/s13321-021-00518-y -
Journal of Clinical and Experimental... Nov 2019Endocrown restorations as a conservative approach to restore endodontically treated teeth still need investigation under fatigue and made in different materials. This...
BACKGROUND
Endocrown restorations as a conservative approach to restore endodontically treated teeth still need investigation under fatigue and made in different materials. This study evaluated the effect of restorative material and restoration thickness on the maximum fracture load of endocrowns subjected to cyclic loading.
MATERIAL AND METHODS
Sixty (60) third molar teeth received an endocrown preparation with three different heights of remaining dental tissue (1.5, 3.0 or 4.5 mm). A leucite-based ceramic (LEU) and a lithium disilicate (LD) based ceramic were selected to manufacture the CAD/CAM endocrown restorations, totaling 6 groups (n=10). The specimens were subjected to fatigue loading (200N, 2 x 106 cycles, water) and then to the single load to failure test (1 mm/min crosshead speed). Data were analyzed by using two-way ANOVA and Tukey tests (< 0.05).
RESULTS
All endocrowns survived the fatigue test. The thickness did not influence the restoration's fracture load (=0.548) instead the restorative material (=0.003). LD showed higher mean values (1714.43 N)A than LEU (1313.47 N)B.
CONCLUSIONS
Endocrowns manufactured with CAD/CAM lithium disilicate blocks showed superior fracture load than the leucite-based blocks after mechanical fatigue. Nevertheless, both materials presented acceptable survival and fracture load as long as the material's minimum thickness and the enamel adhesion are respected. Endocrown, CAD/CAM, Endodontically treated teeth, Failure load, Minimal intervention dentistry.
PubMed: 31700569
DOI: 10.4317/jced.56002 -
Frontiers in Bioengineering and... 2023Nowadays, implants and prostheses are widely used to repair damaged tissues or to treat different diseases, but their use is associated with the risk of infection,... (Review)
Review
Nowadays, implants and prostheses are widely used to repair damaged tissues or to treat different diseases, but their use is associated with the risk of infection, inflammation and finally rejection. To address these issues, new antimicrobial and anti-inflammatory materials are being developed. Aforementioned materials require their thorough preclinical testing before clinical applications can be envisaged. Although many researchers are currently working on new tissues for drug screening and tissue replacement, models for evaluation of new biomaterials are just emerging and are extremely rare. In this context, there is an increased need for advanced models, which would best recapitulate the environment, limiting animal experimentation and adapted to the multitude of these materials. Here, we overview currently available preclinical methods and models for biological evaluation of new biomaterials. We describe several biological tests used in biocompatibility assessment, which is a primordial step in new material's development, and discuss existing challenges in this field. In the second part, the emphasis is made on the development of new 3D models and approaches for preclinical evaluation of biomaterials. The third part focuses on the main parameters to consider to achieve the optimal conditions for evaluating biocompatibility; we also overview differences in regulations across different geographical regions and regulatory systems. Finally, we discuss future directions for the development of innovative biomaterial-related assays: models, dynamic testing models, complex multicellular and multiple organ systems, as well as patient-specific personalized testing approaches.
PubMed: 37576997
DOI: 10.3389/fbioe.2023.1193204 -
Nanomaterials (Basel, Switzerland) Sep 2021Beyond the current commercial materials, refining the grain size is among the proposed strategies to manufacture resilient materials for industrial applications...
Beyond the current commercial materials, refining the grain size is among the proposed strategies to manufacture resilient materials for industrial applications demanding high resistance to severe environments. Here, large strain machining (LSM) was used to manufacture nanostructured HT-9 steel with enhanced thermal stability, mechanical properties, and ductility. Nanocrystalline HT-9 steels with different aspect rations are achieved. In-situ transmission electron microscopy annealing experiments demonstrated that the nanocrystalline grains have excellent thermal stability up to 700 °C with no additional elemental segregation on the grain boundaries other than the initial carbides, attributing the thermal stability of the LSM materials to the low dislocation densities and strains in the final microstructure. Nano-indentation and micro-tensile testing performed on the LSM material pre- and post-annealing demonstrated the possibility of tuning the material's strength and ductility. The results expound on the possibility of manufacturing controlled nanocrystalline materials via a scalable and cost-effective method, albeit with additional fundamental understanding of the resultant morphology dependence on the LSM conditions.
PubMed: 34684979
DOI: 10.3390/nano11102538