My DEA number lets me prescribe ANY drug(except for Schedule I experiemntal drugs and thats simply because I didn't check that box off on the form) that I want to. Do I, no, no, no. Can I, you bet.
Typically you'll find that you'll regularly write for 12-15 drugs. My basic ones are
Antibitoics(Pen VK, Amoxicillin, Clindamycin and E-mycin)
Pain Meds(Vicodin, Darvocet, Ultram and Tylenol #3)
Muscle Relaxants(Flexeril and Robaxin)
Histamine Blockers(Allegra and Clarinex)
Pysch Meds(Amytryptolline - go see a TMJ course by Dr. Jeff Okeson and you'll see where this comes into play)
Sedatives(Valium and Xanax)
90% of the scripts I write are antbiotics and pain meds though. Sure, I'll admit, I've written scripts for inhalers for my wife. I've written scripts for cough medicine and antibiotic eye drops for my partners kids, and even once for one of my hygenists birth control pills, and the pharmacist has never callled. As a matter of fact, about the only time the pharmacist will call is if your writing a script for a narcotic for someone they suspect is a drug abuser(I.E. you're the 5th different doc to give them Vicodin in the last few weeks), or if one of your scripts shows up for an "uncommon" narcotic pain med from your office(for example, my 2 narcotic pain meds that I almost always write for are Vicodin and Darvocet, and the 6 or 7 main pharmacies around my office where most of my patients go have this on record, as well as the fact that I will ususally dispense between 10 and 25 pills with no refills. So if they see a script from me for 50 Percocet with 5 refillls, they'll call me and ask if I really wrote it)
As a liscensed dentist, you will pay the same fee to the DEA ($210 for 3 years at my last renewal) as your medical colleagues, and this gives you all of the same priviledges as them. So when you get your DEA#, if your long time desire is to write a script for Viagra, go ahead and make sure that your scrub bottoms aren't too tight that day!