The email I just got...
"The Committee maintains this small group of highly qualified alternate candidates to ensure all positions in the Class of 2023 will be filled when the program begins in August 2019. As you are aware we follow a “rolling admissions” process for available positions. On December 3, 2018, we began the process of extending offers of acceptance to highly qualified candidates. At this time, we are awaiting responses from those candidates who are considering offers that are projected to fill the positions in the Class of 2023. However, our experience has shown that due to a variety of reasons, a varying number of candidates each year are unable to fulfill their commitment and begin their dental program as planned.
In the event that positions in the Class of 2023 become available between now and the start of our Dental Program, the Dental Admissions Committee will review and consider all confirmed alternate candidates to fill each position as they become available. The Committee does not keep a ranked alternate candidate list and does not select alternates based on a predetermined order. You will be put on the alternate list unless you state you would like to be removed"