Year : 2018 | Volume
: 18 | Issue : 4 | Page : 289--290
Characterization of dental materials
N Gopi Chander
Department of Prosthodontics, SRM Dental College, SRM University, Chennai, Tamil Nadu, India
Dr. N Gopi Chander
Department of Prosthodontics, SRM Dental College, SRM University, Chennai - 600 089, Tamil Nadu
|How to cite this article:|
Chander N G. Characterization of dental materials.J Indian Prosthodont Soc 2018;18:289-290
|How to cite this URL:|
Chander N G. Characterization of dental materials. J Indian Prosthodont Soc [serial online] 2018 [cited 2019 Nov 18 ];18:289-290
Available from: http://www.j-ips.org/text.asp?2018/18/4/289/242616
Characterization in dental material sciences is essential to understand the material structure and properties. It is used to understand the structure and properties of material properties by probing and measuring. The analyzing varies from macro to microscopic level. Many techniques are available, and different methods of characterization are followed. These methods evaluate the particle size, morphology, structural, and optical characterization. The techniques and the instrumentation are diverse and are in constant evolution. With the era progressing, new characterization techniques are evolved.
The technique of characterization can be broadly divided into macro- and micro-characterization. The macroscopic observation is the primary step of characterization of the material. The material is observed for the strength, structure, color, composition, and shape. In prosthodontics, the materials are evaluated for compressive, tensile, flexural, torsion, and fatigue strength. Many studies on new materials lack complete macroscopic evaluation of mechanical, thermal, and physical properties. These testing are essential to understand the material in detail. The properties such as torsion, creep, toughness, hardness, thermal expansion, contraction, coefficient of expansion, differential thermal analysis, thermogravimetric analysis, coordinates of color, and electrical properties are required for more complete evaluation. The use of latest armamentarium that is acceptable by standard organizations is employed to obtain the right properties of the materials.
Microcharacterization uses microscopes. The microscopes investigate the surface or subsurface of materials through electrons, ions, photons, or by physical penetration of probes. It measures the scale of atoms and imaging of bonds. The scale of evaluation varies from a few centimeters to angstroms. The microscopic characterization techniques have been followed over the years. It started from the initial optical microscope to latest atomic microscopy. It can be either classified on the source such as light–optical microscopes, electron–electron microscopes, and probes–scanning probe microscopes (SPMs). It can also be grouped the place of analyzing the sample as scanning point, for example, scanning electron microscope (SEM) or analyzing all at same, for example, transmission electron microscope (TEM). The microscopes that are commonly used for material characterization are optical microscope, SEM, TEM, field ion microscope, scanning tunneling microscope, SPM, atomic force microscope, and X-ray diffraction topography (XRT)., The microscopes aid in determining the composition and structure of the material. In prosthodontics and restorative dentistry, the SEM and TEM have been commonly used. The higher range of characterization is required for advanced studies.
The optical microscopes were the one that was used initially. It uses visible light and lens to obtain the required the information. The information obtained can be limited to 0.2 μm. The use of specialized techniques such as scanning confocal microscopy and vertico spatially modulated illumination produces increased magnification and resolution. The use of shorter wavelength of light such as ultraviolet (UV) light, infrared and fluorescence, phase contrast, and digital microscopes has widened the applications of optical microscopes. Since the major interest of the present researchers is at atomic or nanoscale, the optical microscopes have major limitations in the depth of the field and the magnifications.
The electron microscopes use accelerated electrons for illumination and optical lens for the observations. The magnification is more than the regular optical microscopes which uses conventional light and lens for observations.,, The type of electron acceleration, scattering, penetration, and visualization differentiate the SEM, TEM, and other electron microscopes. SEM provides three-dimensional images in contrast to TEM. However, it provides the details of the surface. TEM produces two-dimensional images and provides information on subsurface, and the accuracy is 0.5 Å compared to SEM which is around 0.4 nm. The use of these microscopes depends on the information required for a particular analysis. Finer and more details are obtained from TEM and advanced microscopes. Conventionally, many studies in prosthodontics restrict to macroscopic evaluation. Its essential microscopic evaluation is made to provide more substantiation. SEM or TEM images of the samples can provide in-depth information and understanding of morphological characterization, particle size, and surface characterization. For advance structure characterization, atomic microscopes and XRT are used. The understanding of these microscopes, needs, advantages, and limitation is essential for its appropriate use and interpretation.
The spectroscopy uses the radiant energy of atoms, molecules, and nuclei. The radiant energy is used to observe the chemical composition, structure, and photoelectric properties of materials. The instruments are classified in accordance to the type and nature of the radiation used or observed. The optical radiation, UV-visible spectroscopy, and Fourier-transform infrared spectroscopy are some of the common instruments that use spectroscopy. Spectroscopic detects rapid structural changes in the biological macromolecules, visualization of particles in the cells, and three-dimensional measurements can be made with advanced techniques.
It is essential that the studies on dental materials have some characterization technique done in accordance to need of the study. The characterization of material aids in better understanding of composition, material structure, bonding and can identify the reasons of failure or success. This aids in better understanding and developmental research.
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