I've never really looked to see who got shut down in the past for sucking. There are various reasons behind the recent closures, but none dealing with accreditation as far as I've read. Just for fun:
Closed:
Oral Roberts University - 1986
Emory University - 1987
Georgetown University - 1990
Farleigh Dickinson University - 1990
Washington University in St. Louis - 1991
Loyola University Chicago - 1992
Northwestern University - 2001
Open:
Nova Southeastern University College of Dental Medicine – 1997
University of Nevada, Las Vegas, School of Dental Medicine - 2002
Arizona School of Dentistry and Oral Health – 2003
Midwestern University College of Dental Medicine-Arizona – 2008
Western University of Health Sciences College of Dental Medicine – 2009
Midwestern University College of Dental Medicine-Illinois – 2011
East Carolina University School of Dental Medicine – 2011
Roseman University of Health Sciences College of Dental Medicine – 2011
Lake Erie College of Osteopathic Medicine School of Dental Medicine – 2012
University of New England College of Dental Medicine – 2013
Missouri School of Dentistry and Oral Health – 2013
University of Utah School of Dentistry – 2013
Bluefield College School of Dental Medicine – 2015