its doable, but i would say it would be better for a dog that you've already had for awhile. reason being is that you need a few months to adequately train the puppy, discpline it, etc. leaving a puppy alone for a few hours at a time can affect its personality growing up. also, you cannot just throw a puppy/dog into a kennel/crate right out of the womb. they need to be trained for that. in the first 2 years, you will really only have time to come back during lunch hour to let them use the bathroom. that will also mean that you need to live within walking distance of school. despite what people will say here on SDN, you will have plenty of time AFTER classes to tend to your dog. if you can't spend 2 hours/day NOT studying, then you've got probs. that should give you enough time to take your dog out for runs and playtime. several of my classmates have dogs, but they do also have signifigant others who aren't in dental school to help give attention to the dog.
