Hi,
I'm sorry this is going on. The liver issues may have come from the release of a lot of bacteria from the teeth into the bloodstream, or may have resulted from an anesthetic reaction. This may also have happened if she had an infectious agent in her system, and the dental lowered her immune system, allowing this to take control. Or, strangely, this might be coincidental.
The good news is that the liver is the one organ that can often repair itself given time. The real question is how much damage was done. At this point, it sounds as though your vet is worrying about infection and inflammation. The steroids concern me a little as steroids can often harm an already compromised liver. But, they are probably using them judiciously to bring down inflammation.
There are a couple of tests that might be worthwhile. One is called bile acids, and tells you how well the liver is still functioning. A second is an abdominal ultrasound, which will tell you what the liver looks like in 3d, and is noninvasive. It will tell you if there is scarring or a mass, or the liver has drastic changes. It might give you the most information on how the long term prognosis looks.
If you can ride this out, often in dogs the liver can do really well. Talk to your vet about these additional tests, and don't lose hope.
James
Dog Veterinarian
10 years small animal veterinarian, acupuncture