Yeah, what wdpre said. :-)

Like I said, I don't have any of the Hiro figures, but I'd imagine they're about the same deal as any other DAZ figure.
What I would do is first, make the "bad" teeth (and gums) completely transparent, or better yet, use LW to may a morph to make them really tiny and out of the way.
Then export the teeth you want from LW, into Poser, so you have only the teeth open up in Poser. When you export from LW make sure the OBJ_UV_map is selected in the surface editor under UV maps, or else it won't follow through in the export. (Why on earth are you using LW 5.5 anyway?)
So then with the teeth object ONLY open in Poser, click on the Setup Room thingie and ignore any warnings.
Then in the Setup Room just draw a couple of bones for the teeth, one for the upper, one for the lower. It may be a good idea to spread them out a bit prior to export. You can let autogroup do its thing and you'll at least have teeth you can control with bones and you can save the new teeth figure in Poser and later parent it to the other figure you want.
The unfortunate thing is, as wdpre pointed out, none of the former morph targets will work, and you'll have to make your own.
There really is no painless way to do what you want. You're either going to have to build a whole new figure, or plan on at least mkaing your own morphs.