Here be dragons!

[StillLifeMiniatures]

I actually work in a lab so I don't have to worry about patients. I work with stone, plaster, metal, torches,wax, duping materials, and all kinds of fun hobby friendly stuff. I also have a scanner and CAD/CAM system and I've been tempted to scan and mill a sculpt. I'm pretty sure my boss would have a fit if I started making minis in zirconia. . I've gotten plenty of holes in my fingers from a misguided bur at high speeds but the advantage of those pieces is being able to control the rotation at a slower speed with a foot pedal. A good deal from eBay or a closing lab would make drilling and pinning so much easier for those that do this as more than a hobby.

 

[QuietiManes]

A faster bit is like a sharper chisel/knife. They tend to be safer in that you don't need or want to push as hard, easier to work with and control.

Any of the better corded Dremel tools have variable speed and 35 or 36,000 rpm max, generally come with multiple bits. For hobby use, I don't see the value in cordless, well, to be honest, I can't see the use for almost anything. But anyway, have a look at the Dremel site to see what's available. Sure to be able to find something in a price range to suit your needs, it's worthwhile to save up for a while instead of buying cheap, you might regret it if you don't.

http://www.dremel.com/en-us/Tools/Pages/CategoryProducts.aspx?catid=13

For our hobby uses those dental tools (and anything marked as and "engraver") tend to be over priced for what is offered. The cheaper rotary tools should be avoided too, I think. Dollar for dollar they aren't up to par. They break down quickly, you can't get parts (like brushes) to replace the worn out items and worst of all, the rpm drops off far too fast when pressure is put on the rotating bit, so even if it does have a max 36k rpm, it drops down to 6-12k in use (where as a better model with the same max rpm will be over twice as fast in use).