Dendrobium with leaves turning yellow and falling off

[steph]

Thank you so much everyone for the quick responses. Junebug: Your detailed instructions were exactly what I was looking for - thanks.

So I went ahead and took the plant out of the pot. The roots indeed look terrible. I'm assuming they are all dead? A few more leaves fell off during the process too.

If all goes well, are the old canes eventually going to grow new leaves? Or are they only left there to provide energy to the new growths? Will it take years before I see flowers again?