Lol I just asked our pre-health advisor about this because I was wondering myself. Here's what she responded (I'm copy/pasting her email):
My question was: "Hello, Do dental schools require or recommend students to be "full-time" all throughout college?"
Her answer: "Most typically we recommend continuing with 2 sciences and 15-17 credits per semester until students get a seat. However we do not recommend going into excess hours to do so. If you are reaching excess hours then just finish what you need."
(I would have to pay extra $ if I take more credits because I have reached the allowed credit hour limit.)
I already applied though.