I'm actually going to disagree partially. Of all the art classes you could take, I think Sculpture with Mixed Media may be one of the least helpful. If this was an upper level course, maybe you'd have more room to design your own sculpture carving projects, but most likely it isn't and you won't, so you'll be working with much larger scale sculpture carving, like shaving down large blocks of plaster, or working with varied media like paper, wire, wood, etc. much of which will be so large scale, it will likely not greatly increase fine hand skills significantly. I can't say any of this for sure cause a course title doesn't tell a lot about what could be in the class, but based on what the 3-d mixed media classes at my college did, I stand by my comment.
I suggest, if you are allowed to take it without a whole lot of prior art prereqs, to take a jewelry making course. After that, a ceramics course AND on top of doing the regular projects (like throwing six 8" cylinders, a covered jar project, a slab built geometric form) you also do fine carving on the ceramic work you make, stuff that would make you squint to see all the details. After that a painting class or fine line drawing class or even a caligraphy class might be good. If you take a ceramics course, pay attention to concepts on glazing and firing and ceramic materials, you'll find it will reoccur during dental school. Those are my recommendations from most to least useful for your final goal. They also may be the most to least frustrating for you, but then, learning to cut a perfect DO-amalgam prep isn't a walk in the park your first time either.
