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ePaper created 2015-09-09, 12:07:54 | version 1.38.0
case report _ implant restorations I plants in the lower jaw and a complete maxillary denture that was aesthetically and functionally in- adequate (Fig. 1). An initial aesthetic evaluation established that the shape and shade of the teeth were inappropriate. In addition, the midline was mis- aligned and the curvature of the maxillary anterior teeth was shaped incorrectly. The poor stability of the denture was caused by insufficient prosthetic support and by the method withwhichithadbeenproduced.Takingthepatient’s requirements and financial constraints, as well as theclinicalconditionofthemaxillaryprostheticfield, into account, we decided in favour of an implant- supported prosthetic treatment modality. The plan was to insert four maxillary implants to retain an overdenture prosthesis using the double-crown method.Thisprocedureisfrequentlyfollowedinsuch cases and has seen constant improvement with the emergence of new technologies and materials. Our protocol required primary telescope crowns milled from zirconia at an incline of 2 degrees and secondary copings obtained by electroforming. This approach combines the advantages of zirconia (primarytelescopes)withthoseofhydraulicretention (galvanic copings). After a complication-free period of healing and osseointegration, the four implants were uncovered and a preliminary impression was taken. Also, a customised tray was created from the resulting model. In order to proceed to the next stage of the treat- ment,werequiredafunctionalimpressionthatwould transfer the exact position of the implants. For this purpose, the four impression posts were splinted together on a custom tray with composite material (Figs. 2 & 3). After creating the working models (Fig. 4), we determined the patient’s vertical dimen- sion of occlusion, the length of the future teeth, as wellasthegingivalsmileline,bymeansofanocclusal Fig. 5_The models mounted on the articulator clearly demonstrate the challenges involved in this clinical case. Fig. 6_Try-in of the wax set-up and evaluation of the aesthetic parameters. Fig. 7_Customised titanium abutments. Fig. 8_Reconstruction of the primary structure after scanning the model, abutments and set-up. Figs. 9 & 10_Grinding and smoothing of the primary structure made from zirconia in a milling unit using CAD/CAM technology. I 23CAD/CAM 3_2015 Fig. 8 Fig. 6 Fig. 10 Fig. 5 Fig. 7 Fig. 9