I guess I'm the odd man out. znny, I hope you got my message. I've been busy with school/research that I wasn't able to answer until recently!
For many people, research, pursuing a DDS/PhD or DMD/PhD is not a priority. We're like the black sheep of the dental herd essentially! Just remember, your class cohort is unbelievably small. 1 to 3 people! My program at UM is 3, I think UCSF has 4 this year, and etc. It's not very big. However, this doesn't mean you won't make friends with the incoming class of that year. I've made many friends in my dental class this summer and the type of research I do is very exciting. Depending on what you want out of life, this may very well be a great decision. However, there is one person in my class that is reconsidering the DDS/PhD and she may be dropping out. So, this isn't a path for everyone.
At UM, we start PhD first. Most programs start DDS first.