Physics in Dentistry

[symbolipoint]

Main Question or Discussion Point

I are aware of "Medical Physics". Now someone, tell us about Physics used in/ applied in Dentistry. Some members should be able to say useful things.

 

[jedishrfu]

You mean like when your uncle acted as dentist tieing a string around a tooth to be pulled, a doorknob and then slamming the door to make it happen.

There was a lot of torque and angular momentum as well as shock and awe.

 

[Bystander]

Physics used in/ applied in Dentistry.

Amalgams, X-ray, imaging, UV curing of acrylates, what specifically were you interested in learning?

 

[BillTre]

Three tings I find interesting in dentistry:

• Amalgams
• Flexible drills for doing root canals (TiNi i think)
• In office 3D scanning of teeth and then milling of caps from blocks of ceramic

 

[symbolipoint]

Amalgams, X-ray, imaging, UV curing of acrylates, what specifically were you interested in learning?

Three tings I find interesting in dentistry:

• Amalgams
• Flexible drills for doing root canals (TiNi i think)
• In office 3D scanning of teeth and then milling of caps from blocks of ceramic

That's the idea. Keep the topics and discussions about this going.

 

[berkeman]

The whole x-ray imaging field has made great strides toward digital film and lower exposures needed for clear imaging. I remember not too long ago when the dental technician would take my dental x-rays using film targets, and have to put them into the developing machine for 20 minutes to be ready for the dentist after the hygienist was done cleaning. Now they come up instantly on the LCD monitor above the chair, so the technician can check them for quality and re-take them if needed. Impressive.

 

[BillTre]

With Respect To: In office 3D scanning of teeth and then milling of caps from blocks of ceramic,

I have experienced getting caps made for my teeth and installed both before and after this system came into operation where I go for dental care.
I the old method, casts were made (probably with silicon rubber) of the tooth to be capped. Then the tooth is ground down.
Make another cast,
Install temporary cap: usually does no fit well (because its off the shelf) so it does not feel well.
send casts off to the cap making lab, wait a week or two.
Go back to the dentist's, get the temps popped off, get the new ones put in (they usually fit and feel way better the the off the shelf temporaries).

The new way,
Using a handheld visual scanner, scan the shape of the tooth to be capped, to gets its shape digitally. This is the shape you want to restore the tooth nub to with the cap you make.
Grind down the tooth to be capped.
Scan the remaining surface. This gives you the surface you want the cap to match to for gluing and fitting purposes.
Then while you are waiting, or if your me, you go watch the machine, the following gets done:
Make a model of the cap you want from the two surfaces collected above.
Feed that into some program that controls a computer driven milling machine in the next room.
This machine holds a ceramic block, maybe a cm cube, on two posts on which it could be rotated.
There was also a dermal like drill unit that could move around quickly and drill in different places from different angles.
Eventually the block was drilled down to the desired cap shape and cut free of the posts.
This would then be installed in your mouth about 1/2 hour after the tooth was ground down, in one visit.
They also fit at least as well as, if not better than the no-digital versions.

So this eliminates:

• repeated visits for a single issue
• reduces time with a lousy temporary cap
• cuts the lab were the caps were physically made, which (theoretically) should be more efficient and result in a price break to the consumer (which I believe is the case).

I think the dentist said it cost about $500,000, probably not including maintenance and supplies.
They get to have more people go through their capping operation and their practice in general because there are fewer visits to be scheduled.

I asked the boss dentist what made him decide to get the system.
He said when the accuracy to the system got to 5 microns (5 x 10^-6m), he though that would be good enough.
Sounds pretty impressive for a handheld scanner.

 

[CWatters]

Physics topics in dentistry add:

Thermal expansion
Surface treatments to improve adhesion (or is that chemistry)
Galvanic properties of materials (avoiding accidental batteries)
Newton's laws (braces etc)
Levers (chewing)

 

[Andy Resnick]

I are aware of "Medical Physics". Now someone, tell us about Physics used in/ applied in Dentistry. Some members should be able to say useful things.

Good lists posted already; I'll elaborate on a few topics-

Some braces wires have a square cross section rather than circular to better support application of torque.
Prosthetic, filling, and sealing materials: multiple materials (filler, crown, etc.) are used to better match the mechanical properties of teeth (which are case-hardened materials). Look up "Gutta-Percha" for something interesting.

https://aip.scitation.org/doi/10.1063/1.1712857

 

[ChemAir]

Because I have an implant:
-Implant design
-Thread/mechanical connections both bone side and crown side
-High precision tooling to work with above
-Imaging for placement