Heat causes thermal insult to pulp & brings Hg to surface of restoration( increased corrosion susceptibility)
Rotary instruments, intermittent pressure, medium speed, wet abrasives, use of pumice or tin oxide
Te best thing to avoid this problems is to avoid amalgam.
If you can't, I recommend you in addition to your own advises:
Make a "cold polish" with the modelling instuments, while the alloy is getting hard. Then you will need much less polishing afterwards.
Take care of your patient's pulp, but don't forget to take care of the health of your patient, your employees and yourself, if you work with mercury. Polishing of amalgam increases also the mercury content of the (breathed) air.
Best, Rudolf
The question of heat generation for dental amalgam should be mute. Why polish? Polishing of amalgams was necessary at one time as the surface was made marginally better against pitting corrosion, but the effect of the oral environment made that advantage short lived. And corrosion was beneficial in the tooth-amalgam interface to "seal" the margin. But then came the increased addition of copper in the amalgam and corrosion effects went away as the Gamma2 stage of the reaction was mitigated. So corrosion does not simply take much of an effect anymore and the margins no longer seal, evidenced by clinical measurements by Leinfelder back in the late 80's. So if the surface was polished to decrease "occlusal" and clinical pitting corrosion then modern amalgams simply no longer need to be polished, post carve burnishing will more than suffice and does not "heat" the pulp. As for swallowing liquid mercury brought to the surface as long as the mercury is not inhaled as a vapor or complexed by bacteria to form an organo-mercury compound then the body simply excretes the liquid metal without harm to the patient as this was exhaustively talked about in the early 90's at a 3 day seminar on the safety of dental silver amalgam at the NIH.
Heat production during polishing of Amalgam fillings can be minimized by maximum water cooling and maximum suction. This makes a difference of some power of tens regarding mercury burden. Rubber dam, in contrast, makes only a difference of 1:2 when making new fillings; so during polishing, rubber dam makes absolutely no sense.
Today the use of amalgam is reduced, but when you need to polish, use a water cooling, succion and reduce the time of contact between the modeling instruments and the restoration.
I agree with AM Dardir. In addition thick layer of insulator under amalgam filling may be used .
i dont think that we need to polish amalgam if carving and burnishing were done well...... to avoid any risk of heat generation that can leads to liberate mercury when temperature reaching 128C.
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