I had posted my concerns about my cat getting its teeth cleaned because of
other pets dying during it.  We discussed what questions should be asked,
precautions to be taken, pre-tests, types of anaethetics.

I found this site that talks in detail and step by step what is done.  I'd
like those in the know to have a read and see if it sounds right.

http://www.cathospitalofchicago.com/library/dental_cleaning_under_anesthesia.html

Is it really necessary to do both, medication, injection then gas?