implants - international magazine of oral implantology

I clinical technique _ restoration removal _There are timeswhenitbecomesnecessarytore- movethecementedprostheticrestorationfromoneor more implants and the prosthesis is not amenable to conventional crown and bridge removal devices. In or- dertoremovetheseprostheses,weneedtogainaccess totheabutmentscrewsbydrillingthroughthecrownor bridge. The challenge is to create the smallest possible access hole and to do this with a minimum of clinical time and effort. This article will describe a simple methodforconstructingandusingadevicetoguidethe creation of appropriate access holes in the implant prosthesis.Iwasluckyenoughnottohaveapatientwith a loose or damaged bridge to use for this presentation, so I used a patient education model to provide the im- agestofacilitatethedescriptionofthetechnique(Figs. 1a&b).Figure2showsthelocationoftheimplants. _Constructing the device The master cast that was used for the construction oftheimplantprosthesisisthecentralelementforthis technique(Fig.3).Longscrewsfromimpressioncopings (Fig. 4) or long laboratory screws are inserted into the implantanalogues(Figs.5a&b).Thecastisblockedout with periphery wax to act as a formwork for the con- struction of the device (Figs. 6a–c). The wax should ex- tendforatleastonetoothoneithersideoftheprosthe- sis.Ifnotoothispresentdistaltotheprosthesis,thenad- ditionalteetharecoveredanteriorlytomaximisestabil- ity of the device. The wax should also block out the full dimensions of the prosthesis. I like to construct the mesial aspect of the device to be sufficiently wide and robustforafingerorthumbtobereadilyplacedonthis areaforstabilisingthedeviceduringpreparationofthe access holes. The model and the screws are lubricated with either petrolatum or a water-based lubricant. Auto-polymerising or light-curing resin is adapted to thecasttocovertheadjacentocclusalsurfacesanden- compass the screws in the implant analogues (Figs. 7a–c). I prefer to use GC pattern resin and in the later stageofpolymerisation,Iremovethescrewsbeforethey potentially become locked in the resin. Once the mate- A simplified method for the removal of cemented implant prosthetics Author_Dr Scott Davis, Australia 32 I implants2_2011 Fig. 4 Fig. 5a Fig. 1b Fig. 2 Fig. 3 Fig. 1a