View Full Version : Summary - Potting Materials for Small Bones

J.d. Johnston
01-11-2001, 03:37 PM
Hello all:

Thanks to everyone who responded to my request for potting materials used with small bones, specifically carpal bones. Below is the original message and a summary of replies.

Original Message

Hello all:

Could anyone offer some helpful suggestions regarding the potting of wrist bones, specifically the triquetrum, lunate and scaphoid bones? I am attempting to test the SL and LT ligaments in tension and am experiencing a lot of difficulty.

I have been using a gypsum product by the name of Dental Stone which acts more as a seat for the bones, as opposed to a material which will "grab" the bones. I am finding the scaphoid especially hard to pot, due to it's strange shape and orientation. Since the gypsum isn't "grabbing" the material I'm fixing the bones with a small S/S pin, which has a habit of pulling through the bone.

I am looking for a new potting material to use. I'm about to try testing with PMMA, but am curious if there are other effective potting materials currently in use.

Thanks, hope someone can help me out.

J. D. Johnston

Summary of Replies

- Fastray - Harry J. Bosworth Company
PMMA based material with a low-heat cure, multiple colors and accurate results. Bit expensive.

- Yellow ?6050 - Technovit
PMMA based material which works well but doesn't really "grab" bones. Bit expensive.

- Cold Cure Acrylic - Buehler
15-20 minutes cure time. Difficult to pot bones without de-fatting the surfaces. May shoot pins through bone and embed both in potting material.

- 2-Part Epoxy - Buehler (Epoxide Resin 20-8130, Hardener 20-8132)
Adheres very well to bone but requires an overnight cure at room temperature.

- Dyna-Cast - http://www.kindt-collins.com/pattern/dyna_chart.html
Non-explosive, minimally exothermic and inexpensive.

- FastCast 891 - Goldenwest MFG (530) 272-1070
2-part eurathane mix with minimal odour and lower toxicity than PMMA. 2-3 minute gel time.

- Bond-o - Body Filler available at Auto Body Shops
Two part mix with characteristics similar to PMMA, but much cheaper.
Very fast cure time but doesn't adhere to bone very well.

- Low-Eutectic Bismuth Alloy
Reusable and safe. Melts at approximately 42C and hardens at room temperature. Bit expensive.

- Low Melting Point Alloy 158F - McMaster-Carr Catalog
Catalog has a number of alloys with a range of melting temperatures. Alloys are sometimes called Woods metal, plumber metal, ...

Thanks again for everyone's help.

J. D. Johnston

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J. D. Johnston
MSc Candidate (Eng)
Queen's University / Human Mobility and Research Center
Syl and Molly Apps Research Centre
Kingston General Hospital
Kingston, Ontario K7L 2V7

Telephone (613) 548-2430
Fax (613) 549-2529
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