My understanding is that they CAN see your entire application, including where you have applied and if you have accepted. It seems that shouldn't be the cas, but it is as far as I know.
Schools can only see your acceptance/deposit starting 4-5-2012.
From the ADEA website
"Applicants Holding Positions at Multiple Institutions. Starting April 1, dental schools
report to ADEA AADSAS the names and identification numbers of candidates who have
paid a deposit, hold a position in a dental school entering class, or both. After April 5,
ADEA AADSAS reports to each institution the names of candidates for its entering class
who hold acceptance(s) at additional institutions. A dental school may rescind an offer of
admission to a candidate who has paid deposits to or holds positions at multiple
institutions. If the dental school chooses to withdraw this candidate from the entering
class, the dental school must give the candidate a minimum 15-day notice."