I personally know from experience that it can really work to your advantage to get your BS in hygiene and still go to dental school. I transferred into the hygiene program at my university during my junior year and still graduated in 4 years. I took a year in between undergrad and dental school to work, apply, and finish pre-reqs (which you can easily get done during undergrad if you go to summer school). During hygiene school, I worked closely with the the dental students and faculty and caught a glimpse of what it would be like to be in dental school. I learned about dentistry in general, perio specifically, surviving clinic, and how to establish a great relationship with my patients. Believe me, getting my degree in something that was relevant to my future was way more exciting then sitting through some anthropology or communications course just to fulfill some requirement. Advantages of taking this route are being very comfortable in clinical situations where most of my classmates are the complete opposite, already being familiar with dental terminolgy and a lot of the course work, being utilized as extra faculty during certain exercises, and the money is great! I can work a few days during a break or on the weekend and make thousands of dollars that I don't have to borrow from uncle sam. So many of my classmates tell me that if they only knew they could have chosen this route and still graduate in 4 yrs, they would have. For myself, there are no disadvantages. I can only speak from own experience but I hope this helps!