From my understanding, the reason why most universities are combining dental students with the med students for the first 2 years is simply because dental programs at these schools do not get enough funding. It is much cheaper for the unversity to educate dental and medical students together.
The upside is that these dental students will receive a broader medically-based education for these first 2 years. The downside, which I feel is greater, includes minimal immersion into dentistry-related subjects such as operative dentistry, fixed & partial removable dentures, and early clinical procedures (impressions, anaesthesia). By the time sudents from these schools enter 3rd year, they will not have had sufficient experience nor confidence to begin clinical procedures on real patients---which is not their fault because these procedures are highly technical and take months of practice to become proficent at them.
I would encourage prospective students to consider schools that have a dental program that is completely separate from the medical program. Dental school is challenging enough with all the hours devoted to lab work and clinical work, why make your life any more difficult by learning medicine on top of your dental studies?