I embedded large bone with ceramic implant. But unfortunately, since the volume of PMMA was too high and the size of implant and bone was also high, the specimen was not hardened and instead a bubbly oozing gel like PMMA was formed. The tremendous heat produced caused the bottles to burst. Please advise me how I can remove the bubbles and re-embed or take sections of this PMMA mass.
Thank you for taking effort to help me out.
please explain more: you filled the PMMA in ceramic bottles? Why? Why dont you use bones, either from dead donors or big animals? Big air bubbles should not be there, if you mix the PMMA normally. If you cool down the PMMA before use lets say to 10 deg.C. there will be almost no air bubbles.
Probably you can try vacuum mixing of the PMMA resin to remove the air bubbles generated during the mixing due to the exothermic reaction. Cooling also will reduce the formation of air bubbles.
I agree with the colleagues above: correct mixing (vacuum if available) and cooling during the exothermic phase.
You may have to go back to square one.
You can use just monomer to redissolve the gooey mess. This is a slow process but will get you back to a specimen covered in a thin layer of gooey PMMA.
Next you will need to take the advice of the others who have responded. Make a new batch of PMMA to embed the specimen. Use a container for the specimen that helps extract heat (like aluminum) and vacuum degas the PMMA while it is embedding. That will help reduce the number of bubbles stuck in the gooey solution while it is hardening..
You could try sonication / ultrasonic degassing of your samples before or after your protocol.
thank you all for answering.
I tried embedding the samples under vacuum only. But I think since the sample bone size was too high and the volume of PMMA was also high the heat generated was also very high, that caused the bottle to break. Nexttime before embedding I will consider your suggestions. But for now I want to retreive my samples back from the semi solid PMMA block. May be I will try to put it in the monomer gain and see.
Does using aluminium container help in proper embedding.
Sunita Ji!
I remember from my chemistry courses, that 2-component glues which heat up, always increase its volume when hardening. It think that the case here, when you use glass as container for your PMMA... it must break!
Sunitha: Of course you may try a metal container. I think aluminium will
I have used aluminum by layering aluminum foil into container. I have also used an aluminum liner in both glass containers and plastic containers. The foil is nice because the outer surface of your embedded piece with be smooth enough that you can see through the PMMA to the bone. This makes it much easier to decide how to section it.