Converting complete dentures to a full arch implant-supported solution is an increasingly popular approach to treat patients with immediate loading protocols.
Converting a pre-existing removable denture (in the case of an edentulous patient) or an immediate denture (in the case of a patient with terminal dentition) to a fixed screw-retained provisional prosthesis is accomplished by doing an intraoral pick up of temporary cylinders, which are secured to transmucosal abutments (or SRA abutments). Sometimes the treating team may choose to secure the temporary cylinders to the head of the implant and avoid an abutment-level connection.
Wide windows aid the prosthesis path of insertion
This conversion technique requires identifying within the intaglio surface of the removable appliance the concentric contour of the implant, securing a healing abutment, and utilizing silicone jaw registration material to identify the implant's position. Then, silicone is removed, and the denture is hollowed in that precise site (opening a window) through which the temporary cylinder is captured with either auto polymerizing polymethyl methacrylate or dual-cure composite material.
Since the prostheses are supported by at least four osseointegrated implants, it is advisable to create wide windows facilitating the draw (path of insertion) of the prosthesis, so the cylinders don't bind, potentially altering the position of the denture during pick up. But wider windows guarantee that pick-up material will contact and capture 360-degrees around the temporary cylinder, which ensures a sturdy pick-up to withstand the forces of mastication and avoids potential fractures of the provisional prosthesis during the osseointegration phase.
However, there can be a downside to utilizing a wider open window. A portion of the anatomical occlusal surface can be lost while hollowing out concentric windows. But you can rebuild any lost occlusal anatomy, and ideally, you should because it's more comfortable for the patient and it facilitates achieving occlusal contact situated axially or on top of the cylinder (the preferred location of an occlusal contact).
Optimizing occlusal contours freehand and with a silicone matrix
Below I describe the freehand application of composite material to optimize the occlusal contours of a hybrid immediately loaded provisional restoration and how to facilitate occlusal reconstruction by obtaining a silicone matrix before the occlusal anatomy is modified.
Ricardo Mitrani, D.D.S., M.S.D., is a member of Spear Resident Faculty.