Stabilising a planning guide in post-mandibulectomy prosthodontic rehabilitation

Patients presenting with grafted reconstructions of the mandible often lack anatomical features that allow for the consistent placement of a diagnostic denture and planning guide. The mucosa covering the graft appears flat with no discernible ridge form. A method was therefore adapted to provide stability to a guide for the placement of implants. A diagnostic denture was constructed to the try-in stage and duplicated in clear acrylic, with radio-opaque markers placed into potential implant positions. Three mini-implants (Southern implants, Irene, SA) were then placed under local anaesthetic trans-mucosally into the bone graft at positions corresponding to teeth 46, 31 and 36. Access holes were created in the flanges of the diagnostic denture/planning guide to enable it to seat over the mini implant heads and to allow for final positioning. Auto-polymerising resin was then placed to cover each of these heads, thus stabilising the guide. The patient was then referred for a CT scan, to be taken with the planning guide in situ, and a surgical guide was made from the CT data, which also used the mini implants for orientation. At surgery, this ensured the optimal placement of the definitive implants, and the mini-implants could then be removed. This method thus provides enormous beneft to both the planning for, and the placement of, implants into grafted bone in mandibulectomy patients.