logo 17 • CAMLOG Partner Magazine • March 2018 14 alveolar process are uncertain and do not allow a reliable prognosis despite a careful and minimally invasive surgical technique. For this reason, it is essential to explain the necessity of bone augmentation to patients before tooth extraction and to inform them about the different clinical measures and treatment options for regeneration. Augmentation of the bony hard tissue defect was performed using two autologous bone blocks (Fig. 9). These were harvested under local anesthesia in the region of the right ascending mandible. In order to ensure maximum adaptation of the vertical block inserted in the area of the extraction socket, the block was extracted with a trephine bur and the recipient site was reshaped using a milling machine (Fig. 10) with a corresponding diameter. Oro-vestibular oversizing of the augmentation area is necessary in order to compensate for subsequent resorption during the healing phase. Due to the insufficient coverage of the vertical defect, a second block had to be applied to the remaining apical defect in the form of a bone cover. The defect was first filled with a mixture of autologous chips and xenogeneic particulate bone replacement material (Bio-Oss, Geistlich, Wolhusen). Both blocks were fixed to the underlying alveolar process with osteosynthesis screws (Ustomed, Tuttlingen) in a stable position. The combination of two blocks shown illustrates the legitimacy of the two established bone flap augmentation procedures with distance osteogenesis and congruent block adaptation with contact osteogenesis. In order to level the transitions between bone blocks and the outer curve of the alveolar process and as resorption protection, particulate bone graft material was coated and covered with a resorbable collagen membrane (Bio-Gide, Geistlich, Wolhusen) as part of guided bone regeneration (Fig. 11). Implantation The drilling template was fabricated in the laboratory in preparation for the implantation, which was performed approximately four months after bone block augmentation (Fig. 12). For this purpose, a model and a thermoform film of the initial state prior to tooth extraction were created in which the assembled drill sleeve was inserted according to the positioning and axial direction of the original tooth 11. Wherever possible, initial models should be prepared before tooth extraction in order to provide sufficient anatomical references for the further steps. Otherwise, the drill sleeve is primarily aligned towards the later prosthetic insertion direction under consideration of the adjacent neighboring teeth. Since the technician was aware that maximum bone reconstruction of the implant bed was planned, it was possible to fabricate the drilling guide according to purely anatomical and prosthetic design features without having to take into account any bone deficits which were anyway difficult to detect in the model. Figure 13 shows the orthopantomogram with inserted drilling template and radiopaque sleeve as well as the two osteosynthesis screws in situ. The frontal view of the clinical situation four months post-augmentation is shown in Figure 14. In this context, the improvement in the vertical alveolar ridge dimension in comparison to Figure 6 is of particular importance. The Fig. 15: Occlusal view corresponding to Fig. 14 with rehabilitated alveolar ridge width. Fig. 16: Opened augmentation area with osteosynthesis screws in situ. Fig. 17: Template-guided implant pilot hole after removal of the osteosynthesis screws. Fig. 10: Trephine drill for bone block removal and ablative bur for preparing the recipient site with a corresponding diameter. Fig. 11: Collagen membrane covering of the augmentation site as part of guided bone regeneration. Fig. 9: Bone blocks fixed with osteosynthesis screws for augmentation (horizontal block: bone cover method; vertical block: sitecongruent block). CASE STUDY
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