Here's a little info/insight for you. First off if you were thinking about Pharmacy School, I'd assume that you've taken a chemistry based curriculum so far, and have hopefully done well. Thats a big plus, and has a bit of relevance for the dental profession.
Now, most folks upon graduating from dental school nowadays don't open a practice by themselves but rather enter into a practice as a second or third dentist in an office. Its often quite adventageous to do this because your heading into a practice that is up and running with patients, and the demographics of dentists right now and for atleast the next 10 years have many more dentists retiring per year than graduating, so there are alot of opportunities out there.
Now for hospital based dentistry, yes, it exists, and it is a rather small minority in dentistry. Most full time hospital dentists are faculty of a residency program and not only handle the dental needs of the patients in the hospital, but also will generally spend a great deal of time taking special needs patients to the operating room for their dental needs. Another way to get a combination of private practice and hospital practice is to volunteer to be the dentist for the local nursing home, or to obtain hospital privileges as a general dentist. In this last modality, you will be on call to the hospital for their dental needs a set number of days per month/year.
Keep your options open, dentistry is a great profession to be heading into!
