I'm a DS1...
Never went to med school but just from my own personal observation.
Biochemistry, Immunology, Physiology, Pathology, Histology, Pharmacology, Radiology
The classes are the real deal, I would say for pathology, histology, and radiology we obviously concentrate on the oral aspect instead of the rest of the body but we still learn the rest of the body. For radiology, I imagine we would be restricted to the head.
Dental anatomy...anatomy of teeth is complex as it is, not even including morphogenesis, development, genetic deformities, occlusion, etc.
Gross anatomy is one class I believe medical school separates itself. At least at our dental school, we don't pay too much attention to the lower half of the body. We just need to know that we have muscles there. They are not teaching clinically relevant information about the legs since we do not operate in that area. I would guarantee we are more comfortable with head & neck than a medical doctor who is not ENT, plastics, neuro.
Being a surgeon of the mouth is not particularly easy and to be great, requires great manual dexterity. We are talking about precision down to half a millimeter required when you have a patient lying in a chair. Not to mention, you will need to maintain correct posture to practice 20+ years.
Is it chill?
Yes and no. Our dental class avg gpa is ridiculously high. Our class has highest average entering GPA of our school's history at 3.6 GPA. Just as high as medical school. Naturally the students are brilliant and extremely smart. Expect to be shocked to say the least when you are sitting on top of that curve instead of two standard deviations to the right of it.
You make of dental school what you want however. If you want to get straight As and consistently set the curve. I guarantee those top students would have no problem in medical school and are stressing just as much as medical students. We spend so much time practicing our hand skills that it is impossible however for dental school to be more didactically demanding than medical school. If you want to specialize in dentistry, it seems as if unless one is naturally gifted with photographic memory, you will be working your butt off. If specializing is not your thing, dental school can be super chill, and I would argue that it does not matter if your graduate last in your class as long as your hand skills were up to par so you could prepare beautiful preps.
For myself, I still get 8 hours of sleep a night and good grades, however I have no doubt I will find myself on the lower end of a curve in no time.