Classes are back in session on January 2nd. I would send a letter of intent addressing the admissions team. I would write about your experience with faculty and students and why specifically you want to go to this school as opposed to any others. Talk about what things stood out to you, and how your experiences and personality would make a great fit for this program based on what you saw and what you've read on the website as far as the mission statement goes etc. Also mention any things you are currently working on that show your commitment to dentistry that you are actively doing such as research, shadowing, dental assisting, or even volunteer work. Try to mention new things that aren't already on your application or things you're actively doing like working at a dental office still. Keep it brief (no more than a page) and professional with formal greetings and a closing signature.
They send out admissions in waves each month, there are more to come. I don't know when exactly the next waves of admissions will be, but I'm sure people on here will update.