I took a year off for medical reasons. I highly recommend against it unless it cannot be prevented. Here are a few reasons:
1. When you have the same classes, every day, eight hours a day, the students become very close knit and it is difficult coming in to that environment.
2. We take part I after our second year. That means that there is some information that will be nearly three years old when i take the test.
3. I was amazed at how much my basic skills had atrophied. Granted, I did nothing dental related during my year off, so this could have been helped.