CAD/CAM international magazine of digital dentistry No. 4, 2016

| cone beam supplement treatment planning based on CBCT 38 CAD/CAM 4 2016 1.0–3.0mm in the implantation zone. The CBCT– Scanrevealedahorizontalcrestalbonethicknessof 1.09mm in region 32, and 1.74mm in region 44. Treatment planning and augmentation procedure After patient-consultation, we opted for a two- stagesurgerywithanintraorallyharvestedautoge- nous bone-graft and a delayed implant treatment afterahealingperiodofatleastfourmonths.Asthe vertical dimension of the implant region appeared to be sufficient enough for placement of implants withastandardlength,wedecidedtocutoff5.0mm of the thin and sharp-edged alveolar ridge by osteotomy, in order to create an autogenous lateral onlay bone-graft for horizontal augmentation in the anterior alveolar ridge. This protocol comprised inourviewtheadvantageoftheavoidanceofdonor morbidity, because the donor site was the receptor site as well. After creation and mobilisation of the mucoperiostal flap, the very thin and sharp edge of the atrophied alveolar crest became visible (Fig. 4). The osteotomy of the bone was performed with a saw (Bone splitting system, Helmut Zepf Medizin- technikGmbH,Seitingen-Oberflacht,Germany;Fig.5). Subsequently, the graft was detached from the anteriormandiblewithchisel(Bonesplittingsystem, Helmut Zepf, Medizintechnik GmbH, Seitingen- Oberflacht, Germany; Fig. 6) and a cortico-cancel- lousboneblockwasobtained(Fig.7).Thebonegraft wasfixedatthebuccalsideoftheanteriormandible (region 34–44) with four 8.0mm long titanium microscrews (Storz am Mark GmbH, Emmingen- Liptingen, Germany; Fig. 8). A combination of autogenous bone chips and particulated xeno- graft (BEGO OSS, BEGO Implant Systems, Bremen, Germany) was placed in the small remaining space between the bone block and the alveolar proces- sus, as well as around and on the bone graft. The augmented site was covered with a platelet rich in growth factors (PRGF) membrane (BTI Biotech- nology Institute, Blue Bell, USA) and additionally withabarriermembraneforguidedboneregenera- tion (GBR, Bio-Gide, Geistlich Biomaterials Ver- triebsgesellschaft mbH, Baden-Baden, Germany; Fig 9). The healing of the graft was uneventful and withoutanycomplications,likemembraneexposure, beingclassifiedasafrequentpost-operativecompli- cation.5 The patient was provided with a removable provisional prosthesis. Re-entry and implant surgery The re-entry for the delayed implant placement protocol was planned after a healing period of four months. With regard to the soft aspect of the augmented area of the anterior mandible, the Fig. 7: Aspect of the bone harvest. Fig. 8: The graft was fixed with four miniscrews. Fig. 9: The osseous graft was covered with a PRGF membrane and a barrier membrane for GBR. Fig. 10: Sufficient horizontal ridge dimensions after a healing period of four months. Fig. 11: The CBCT shortly before re-entry demonstrated a significant gain of bone volume after augmentation. Fig. 12: After flap elevation, a good osseointegration and stabilisation of the autograft was noticed. Fig. 13: After the fixation screws were removed, the four implants with a diameter of 3.75mm and a length of 11.5mm were inserted epicrestally without a surgical guide. Fig. 7 Fig. 8 Fig. 9 Fig. 10 Fig. 11 Fig. 12 Fig. 13 42016

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