Ultrasound Scans of teeth instead of x-ray?

  • Thread starter magi
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  • #1
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Main Question or Discussion Point

Hello.

I took a course in Ultrasound and I wonder why dentists dont use that instead of X-ray.

The patient only need to fill his/hers mouth with water and then it is possible to use Ultrasound Scans in the mouth of the patient without any jonisating radiation.

It could even be possible to use under a drilling if the dentist look at the Ultrasound Scans screen.
It is possible to scan metall with ultrasound.
Maybe it has to be in contact directly with the tooth to be able to get enough signal in to the tooth becouse of reflections?

Why cant it be done?


Regards Magi
 
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Answers and Replies

  • #2
Danger
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I'm inclined to suspect that there might be resonance problems, but that's only because I've experienced bad toothaches caused by high-frequency vibrations. Still, that should be tuneable. I wonder if there might also be the possibility of teeth exploding if the pulp reacts to the sound (like popcorn).
 
  • #3
berkeman
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I suspect it's a resolution issue. What is the wavelength of the ultrasound instrument that you would use? What is the resolution of present X-ray film at the 1:1 magnification used in dental X-rays?

Also, I believe that ultrasound works best for soft tissues -- I haven't seen it used for bone scans before....is it used for bone?
 
  • #4
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Same reason ultrasound isn't used to image bones. you get plenty of reflection of the ultrasound energy at the tissue/bone interface, but very little transmission into the bone. That means there's little to no sound energy reflecting back from any boundaries within the bone for the transducer to detect.

In addition, ultrasound images are generally formed by assuming a constant sound velocity in tissue (~1540 m/s). While not strictly true for all tissue types, it's reasonably close. The speed of sound in bone however is much higher. The ultrasound machine has no a priori way of knowing what reflections come from what objects, so you end up with a highly distorted image.

The other problem is resolution. Ultrasound isn't really capable of great resolution, usually things larger than 3-4 mm or so. Cavities in teeth are a heck of a lot smaller than that, and by the time they're large enough to be detectable by ultrasound, it means a major procedure for the dentist to repair. Dental films on the other hand can resolve objects less than 0.5mm in size, so the dentist can find smaller cavities and do less drilling to repair them.
 
  • #5
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berkeman said:
I haven't seen it used for bone scans before....is it used for bone?
The only application of ultrasound to bone I'm aware of is in measuring bone density. There are a few ultrasound based bone density units that measure sound transmission through bone (usually the heel) to quantify bone mineral density. AFAIK, there are no ultrasound bone imaging applications except maybe to characterize lesions that might be found in trabecular bone.
 
  • #6
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Would there not also be the possibility of damage to the middle or inner ear?
 
  • #7
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kleinjahr said:
Would there not also be the possibility of damage to the middle or inner ear?
I measured bone density with ultra sound at my university when I took the course ultrasound and when using scanning equipment there is no possibility to damage your ear what I read.

But No one can ever be 100 % sure.

You can die if drinking to much water too. :)
 
  • #8
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kleinjahr said:
Would there not also be the possibility of damage to the middle or inner ear?
at the energies used in conventional imaging ultrasound, there's little possibility of damaging anything.
 
  • #9
trying t gether p[citures of teeth under ultrasound

im studying for an m phil in 3 mnths and im looking for images of teeth taken with ultrasound and any info that any one has about this.THANX
 
  • #10
yo wassup y'all
 

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