My thoughts:
• 15K may seem like a lot (which it is) but it is NOTHING compared to the debt you will owe if you:
1. Attend a U.S. dental school or
2. Pay all 4 years of pharmacy tuition
If you're going to make a change, sooner is better than later financially speaking. However,
• I would NOT drop out of P. School unless you are ABSOLUTELY SURE that you want to pursue dentistry. You better MAKE SURE this is what you want.
•Your opinions regarding the differences between pharm vs. dental:
I'm considering dropping out of pharmacy school for dentistry. I know it's also saturated, but it doesn't look as bad as pharm. I wouldn't be working overnight or New Years'. I wouldn't have to deal with customers demanding me to work faster because they don't know what my job is. As a dentist, I think the overall work conditions would be better and I'd actually enjoy doing my job. I don't have to be rich, but even with saturation dentists make more money than pharmacists. Patients would actually see me as a healthcare provider and respect me more. I could eventually do my own thing, have my own business and be my own boss.
...are a bit naive, in my opinion. As many have said before me, the grass is always greener on the other side. The aspects you comment on - patient's demands, work speed and conditions, respect, and being a practice owner - are HIGHLY variable within dentistry and location of practice. I could go through and offer counterpoints to each one, but I think it's enough to tell you that dentistry isn't some "saving grace" that you may think it is. I just think you should be honest with yourself and explore some of the upcoming and growing challenges of dentistry (corporate expansion, falling reimbursement rates from insurance companies, increasing difficultly of new grads to enter private practice, economy sensitivity, etc.) before making your decision.
My advice:
•Contact U of PR dental admissions and discuss your situation. Ask them if your desire to switch and (eventually) apply and enroll in UPR dental is realistic.
•Start looking for a job NOW if you're serious about dropping out. Preferably in the dental field so that you can gain experience.
•Shadow shadow shadow. You need dental experience for both personal growth (i.e. You NEED to verify that dental is what you want do do as a career) and for your application.
•Study for the DAT. There are numerous resources for this on SDN. The DAT discussions forum is a good place to start.