Dr. Javier Andrade, a cerecdoctors.com Mentor, shows this technique. Here’s his description:
This is a case done with sleeve in sleeve, was one my first guided cases. It is an option when you don’t have the keys, and in a clinical situation like yours. Basically this are small sleeves that are adapted to the drill and fit on a master sleeve in the guide, depending of the size of the drills they are only going to provide you like two of these, I am not sure if more than that...
You can view more here:http://www.cerecdoctors.com/discussion-boards/view/id/29568