go to digital babes (link from this site's sidebar and get some of kozaburo's transmapped hair. It works wonderfully (both in poser and bryce)! as commented, definitiely reduce the ambience on the teeth, add some specularity and a trace of reflection. I might also suggest, selecting the teeth and moving them slightly back into here mouth - they look as if slightly into the top lip (use object space to control this move) As to the wierd shadows, how are you lighting this? I think there is more than sun here or you have some non-camera visible stuff. Let us know please.

Pass no temptation lightly by, for one never knows when it may pass again!