Research Microscopes

A Magnified Microscopic Image Is Worth More Than A Thousand Words.
DARK FIELD MICROSCOPE
PHASE CONTRAST MICROSCOPY
POLARIZED LIGHT MICROSCOPY
FLUORESCENT MICROSCOPY
STEREO MICROSCOPE
ELECTRON MICROSCOPY

1. RESEARCH MICROSCOPES DR. AMITHA G, BDS, MDS ORAL AND MAXILLOFACIAL PATHOLOGY

2. A Magnified Microscopic Image Is Worth More Than A Thousand Words .

3. DARK FIELD MICROSCOPE

4. DARK FIELD MICROSCOPE Plant spores Solar eclipse Stars are shining both night and day, but they are invisible during the day because the overwhelming brightness of the sun "blots out" the faint light from the stars, rendering them invisible. During a total solar eclipse, the moon moves between the Earth and the sun blocking out the light of the sun and the stars can now be seen even though it is daytime. In short, the visibility of the faint star light is enormously enhanced against a dark background.

5. Principle : It works by illuminating the sample with light that will not be collected by the objective lens and thus will not form part of the image. This produces the classic appearance of a dark, almost black, background with bright objects on it.

6. USES: To view fungi, live bacterium, mounted cell and tissue. e.g Treponema pallidium , Leptospira , vibrio cholera, endospore. Examination of live blood samples. Study cancer cells.

7. PHASE CONTRAST MICROSCOPY

8. It is an optical- microscopy  technique that converts  phase  shifts in light passing through a transparent specimen to brightness changes in the image.  Phase  shifts themselves are invisible, but become visible when shown as brightness variations. Used for microscopic observation of unstained biological material PHASE CONTRAST MICROSCOPY

9. USES: Visualization of internal cellular components. Diagnosis of tumor cells. To examine living and undistorted cell . For studying living and/or unstained material, such as cells and tissues in culture. Specimens that are thin and scattered in the field of view examination. Dental Plaque Bacteria Epithelial cells cocci Dental Plaque

10. POLARIZED LIGHT MICROSCOPY

11. Transverse wave light whose vibration possess direction is called polarized light. Light from an ordinary light source (natural light) that vibrates in random directions is called nonpolarized light. POLARIZED LIGHT MICROSCOPY

12. Examination of normal and decayed hard tissue structure of teeth. In Dentigerous cysts, thickness of fibers showed greenish yellow color and thick fibers showed orange- red color. To compare the pattern of collagen fibers in odontogenic cysts. USES

13. In OSMF, to analyze collagen distribution in different stages using the picrosirius red stain under polarized microscope.  Protein : Collagen , amyloid, CEOT , keratin are stained with congo red and examined by polarization microscopy. collagen fibers in oral squamous cell carcinoma microscopy. collagen fibers in oral squamous cell carcinoma

14. FLUORESCENT MICROSCOPY

15. Various fluorescent dyes are used which gives property of fluorescence to only specific part of the cell and hence it can be focused. Depends upon illumination of a substance with a specific wavelength (UV region i.e. invisible region) which then emits light at a lower wavelength (visible region). FLUORESCENT MICROSCOPY

16. Bacterial pathogens (e.g., Mycobacterium tuberculosis) can be identified after staining them with fluorochromes . To distinguish live bacteria from dead bacteria by the color they fluoresce after treatment with a special mixture of stains. To diagnose auto immune disease specially vesiculo bullous and dermatological lesions e.g : pemphigus , pemphigoid USES

17. STEREOMICROSCOPE

18. STEREOMICROSCOPE INTRODUCTION It was first designed by GREENOUGH in 1897. It is also called as BINOCULAR DISSECTING MICROSCOPE .

19. PRINCIPLE It is designed for low magnification observation of a sample, typically using light reflected from the surface of an object rather than transmitted through it. It uses two separate optical paths with two objectives and eyepieces to provide slightly different viewing angles to the left and right eyes. This arrangement produces a  three-dimensional  visualization of the sample being examined.

20. Microdissection of pathological specimen In dentistry in the field of endodontics, prostodontics and implant dentistry To check surface structure Micro leakage Bonding defects And to see the margins of finished prosthesis USES F ailure in the root canal filling - yellow circle. 

21. ELECTRON MICROSCOPY

22. Electron Microscopes (EMs) function exactly as their optical counterparts except that they use a focused beam of electrons instead of light to "image" the specimen and gain information as to its structure and composition. The Transmission Electron Microscope (TEM) is patterned exactly on the Light Transmission Microscope except that a focused beam of electrons is used instead of light to "see through" the specimen. The Scanning Electron Microscope (SEM) development was due to the electronics involved in "scanning" the beam of electrons across the sample. ELECTRON MICROSCOPY

23. SEM SEM focuses on the sample’s surface and its composition and shows only the morphology of samples. SEM allows for large amount of sample to be analysed at a time SEM is used for surfaces, powders, polished & etched microstructures, chemical segregation SEM, picture is shown on monitor. SEM also provides a 3-dimensional image TEM TEM provides the details about internal composition. show many characteristics of the sample, such as morphology, crystallization, stress or even magnetic domains. The sample in TEM has to be cut thinner TEM has much higher resolution than SEM. TEM only small amount of sample can be analysed at a time. TEM is used for imaging of dislocations, tiny precipitates, grain boundaries and other defect structures in solids In TEM, pictures are shown on fluorescent screens TEM provides a 2-dimensional picture.

24. USES Preparation of tissues and cells, as well as negative staining of macromolecules, viruses, and nanoparticles.  Used to see the ultra structure of cells Structure of protein molecules Organization of molecules in viruses and cytoskeletal filaments Arrangement of protein molecules in cell membranes

25. THANK YOU