Those are two completely mutually exclusive careers. It's like trying to decide between being an engineer or a fireman. That being said, there will probably be more room to choose the demographic you would like to work with in dentistry, whereas a lot of physical therapists are forced to see mostly geriatric patients. Sports PT and children are more competitive jobs. As far as schooling, it's not a contest. PT is far easier and, despite my personal objectives, will receive the title of Dr. (despite completing as many course hours in the entire program as a dentist will do in 2 years...).
That being said, I'm not necessarily passionate about teeth. I'm passionate about serving people, particularly indigent populations, in a tangible way. I personally chose to pursue improving the oral health of my patients. Figure out your passion, and follow it. It's really a silly question to be quite honest, and I don't think you've really given it enough serious thought or have been exposed to the fields to make a sound decision at this time, or so it would seem.