As scanning microscopy is comparatively expensive, can stereomicroscopy be used to analyse dentinal tubule morphology ( I agree and understand the detailing is best under SEM) if yes what magnification is ideal..
Dear Prashant,
if I understand your question correctly, you propose to use a simple optical microscope (a stereo loupe rather than a transmitted light microscope, i.e. this type of machine: http://www.news-medical.net/image.axd?picture=2012%2F12%2Folympus4.jpg). These generally have a much lower resolution than standard transmission / reflected light microscopes whose maximum resolution is similar to the wavelength of light, i.e. ~ 0.5 microns. However, such low values are only attained under ideal conditions with special objectives (oil immersion, 100x or higher objectives). Stereomicroscopes have much lower resolution, certainly above a few microns.
Seeing that dentinal tubules are typically at most ~ 2.5 microns in diameter, you will not be able to resolve them with a stereomicroscope. However, you should (just) be able to resolve them with a standard optical microscope, as described above (this type of machine: http://www.microscope-microscope.org/basic/microscope-images/138-microscopes-lg.jpg). Now depending on what you are interested in, this might just be enough. E.g. it would be sufficient to estimate their density or get an idea of the shape of the cross sections. However, the detailed morphology of the inner surfaces, for instance, will not be resolvable, since this is expressed on a much smaller scale than the resolution limit of ~0.5 microns. For this you would definitely need to use an SEM. SEM is generally much better for the visualisation of surfaces, even at the same magnification, because it has much better contrast effects.
I hope this has been helpful. Let me know if you have any further questions.
Best wishes,
Max
Dear Prashant,
if I understand your question correctly, you propose to use a simple optical microscope (a stereo loupe rather than a transmitted light microscope, i.e. this type of machine: http://www.news-medical.net/image.axd?picture=2012%2F12%2Folympus4.jpg). These generally have a much lower resolution than standard transmission / reflected light microscopes whose maximum resolution is similar to the wavelength of light, i.e. ~ 0.5 microns. However, such low values are only attained under ideal conditions with special objectives (oil immersion, 100x or higher objectives). Stereomicroscopes have much lower resolution, certainly above a few microns.
Seeing that dentinal tubules are typically at most ~ 2.5 microns in diameter, you will not be able to resolve them with a stereomicroscope. However, you should (just) be able to resolve them with a standard optical microscope, as described above (this type of machine: http://www.microscope-microscope.org/basic/microscope-images/138-microscopes-lg.jpg). Now depending on what you are interested in, this might just be enough. E.g. it would be sufficient to estimate their density or get an idea of the shape of the cross sections. However, the detailed morphology of the inner surfaces, for instance, will not be resolvable, since this is expressed on a much smaller scale than the resolution limit of ~0.5 microns. For this you would definitely need to use an SEM. SEM is generally much better for the visualisation of surfaces, even at the same magnification, because it has much better contrast effects.
I hope this has been helpful. Let me know if you have any further questions.
Best wishes,
Max
I've observed a lot of tubules under SEM, never have tried a stereomicroscope... For sure it's resolution is not enough. But (just may be "but") you can try to observe tubulas after etching. Or even better after embedding in PMMA and etching. May be contrast will be high enough to observe direction of tubules. Just a reminder: even telescopes cannot resolve stars, however star are visible thanks to their huge contrast. But if you want good results, you have to use SEM.
Thank you Max and Vladimir Dusevich.
I was interested to observe the morphological alterations (if any) in dentinal tubules after exposing the tooth to different sterilization techniques and looking for alternate technique for SEM can you kindly suggest any such technique?
Pleasure!
There are a number of alternative microscopic techniques with (perhaps) sufficiently high resolution, depending on the exact question. However, they might present challenges in sample preparation and/or implementation. What comes to mind are:
1) UV-microscopy - the lower wavelength of UV light compared to optical gives somewhat better resolution. This might be enough if you are just interested in whether the openings of your tubules get etched (i.e. become larger) during the sterilisation treatment. You would probably be looking to use a reflected-light system as they do in the semi-conductor business. However, unprepared (i.e. non-polished) tooth samples are not ideal for such systems, such that you would have to think about preparation a little.
2) Atomic-force microscopy (AFM) - very high resolution. However, it also requires planar surfaces, which would present some sample preparation challenges. The spatial resolution of this technique is so high that it might be a little bit overkill.
3) Laser scanning microscopy - also capable of sub-micron resolution. However, I am not familiar enough with the technique to say whether implementations suitable for opaque / translucent materials such as dentin exist, allowing for the visualisation of surface morphology.
Perhaps someone else has more to add to this list, and the suitability for your question. It would also help to know what kind of morphological changes you are looking for, i.e. on what scale they are expected to happen - 10 nm? 100 nm? 1micron?
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