Implant Tribune Italian Edition

14 Implant Tribune Italian Edition - Settembre 2013 < pagina 13 One must choose carefully be- tween the more pleasant approach of using short and angled implants with long crowns and the more dif- ficult approach of bone augmenta- tion. Three-dimensional planning provides indispensable informa- tion in cases like these. With ref- erence to typical defect patterns, Figure 3 demonstrates that restor- ing bone volume for very different defects can be problematic. A typi- cal reconstruction using a surgical guide for pilot drillings in a short- ened row of teeth with good initial conditions is depicted in Figures 4a and b. Edentulous jaw Three-dimensional planning is of vital importance for determining the treatment approach for im- plantation in edentulous jaws. For instance, one has to decide upon whether and which augmentative measures are required and wheth- er a removable or fixed prosthe- sis is suitable. With regard to the last point, it must also be decided whether extensive single-tooth replacement is possible, wheth- er small or large bridges must be used, and whether a greater inter- maxillary distance must be filled prosthetically by longer crowns or by a mucosa substitute. The number of implants for fixed dental prostheses include the All- on-4 concept (Nobel Biocare), the consensus conference recommen- dations of six implants in the man- dible and eight in the maxilla, and tooth-by-tooth reconstruction up to the first molar. The multitude of planning infor- mation and treatment possibilities requires a great deal of planning, which is always justified because of its significant consequences. Plan- ning based on digital casts is not appropriate in these cases, since the support of the cheeks and lips by the prosthesis is important and this can only be determined with the help of and for each patient. Here, the advantages of prosthetic planning are particularly evident. Edentulous jaws often require a special approach (see Figs. 5a & b for an example). Extensive augmentation is fre- quently necessary (Figs. 6a-f). The required length of the teeth, however, has to be clarified with the patient before treatment and depends on the amount of tooth displayed during lip repose (Fig. 6e). Quite frequently, implants are placed inter-foraminally in the mandible, often because extensive augmentation is still problematic in the lateral mandible. Figures 7a and b show a patient with six implants and an extension bridge. Even in cases of seemingly simple implantation for removable den- tures in an edentulous jaw, 3-D planning and a planning cast are needed to verify functional recon- struction and soft-tissue support. > pagina 15 Figs. 5a-f - Two-step technique in a case of advanced atrophy of the alveolar process prior to fixed prostheses: Horizontal and vertical augmentation intra-operatively, fixed bone block (left) and covered with membrane (right; a). Healed post-augmentation (b). Post-implantation (c). Radiograph after placement of the bridge (d). Prosthetic result, lip repose (e). Prosthetic result, lip raised (f). Despite augmentation, long crowns were still required. Tab. 1 - Workflow for 3-D implant planning. Tab. 2 - Workflow for 3-D implant planning with CAD/CAM. Figs. 4a & b - Three-dimensional planning in an edentulous maxilla (a). Prosthetic loading with good initial conditions (b). Letteratura Internazionale