lol, i don't think cooking will be too bad, and NOOOO Dentistry is a full time course! (so is medicine) you will never be able to get a part time job! lol... and within the 9-5, i'm sure theres breaks and times for private studies...
For paying rent, you'll have to get a loan or something, but I don't think anyone will be able to cope gettin a job on top... AS said before, Dentistry is not an easy course.... so you need to be 100% sure you want this career and you are dedicated!