don't know how to fix, but would it be terrible to leave lion as in? a shabby chic kinda thing? And if it looks like it was added previously, apparently it didn't work as it fell again.

ETA would probably have to drill into lion, stick wire and then insert a formed fang. Or else have somebody do it and expense would negate savings from buying at estate sale. Lion is quite lovely.

It wouldnt be terrible, I just thought maybe Id try and get him off the liquid diet :)

Someone suggested whittling down wooden dowel rods and spraying a cement paint over them, another suggested using a dremel on some cement cuts as well.

Wood would eventually rot, I'd think. Dremelling a small cement piece into shape sounds feasible, but key is attaching to mouth. A piece of wire seems like it'd last longer than wood.

if just for looks, plaster of Paris would be easier to work with. You can get a small kit at a craft shop. Plaster would likely stick to well cleaned cement but I'd still give some thought to using wire. Then paint with acrylic paint to match concrete, also avail @ craft store.

Kwikwood or a exterior wood epoxy. You can shape and file or sand. I'm not sure if it would stick but I bet it would.