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PUBLISHED IN DUBAI www.dental-tribune.me January-February 2018 | No. 1, Vol. 8 Augmentation and implant treatment SUBSCRIBE NOW www.me.dental-tribune.com/e-paper/ issn 1868-3207 Vol. 18 • Issue 4/2017 implants international magazine of oral implantology 4 2017 Two-stage surgery in the severely resorbed edentulous mandible By Dr Marko Nikolic, Croatia Introduction An adequate bone volume at the future implant site is a prerequisite for ideal implant placement and im- plant success. A residual bone with a vertical dimension less than 5.0 mm indicates a cut-off point and implies the need of additional augmentation procedures in connection with im- plant insertion, whereas higher val- ues of the alveolar crest ≥ 5.0 mm are considered to be sufficient for treatment with standard-diameter implants without the urgent need of any horizontal bone augmentation.1 Distant donor sites like the anterior and posterior iliac crest and intraoral areas like the retromandibular and the interforaminal region of the chin are common sources for harvesting autogenous bone-grafts. Depend- ing from the donor site, patient and surgeon should be aware of the pos- sible confrontation with various advantages but also disadvantages when harvesting the bone. Harvest- ing bone from the iliac crest requires patient hospitalisation, and surgery under general anaesthesia, whereas intraoral bone harvesting can be per- formed ambulatory and under local anaesthesia.2, 3 The main problem with autogenous bone grafting is represented by the high risk of patient morbidity, causing pain, swelling, and healing problems at the donor site.3 The aim of this case presentation is to dem- onstrate a predictable, two-stage operating protocol for the horizon- tal augmentation of the severely resorbed, edentulous anterior man- dible with an autogenous bone graft, harvested from the crestal alveolar ridge at implant site, in order to cre- ate a sufficient bone volume for the later implant therapy, without do- nor morbidity for the patient. Patient data The 47-year-old male patient visited our dental office in order to renew his old and poor fitting prostheses in the lower and in the upper jaw. The remaining five teeth 32–43 in the front of the lower jaw had been removed three months previously due to a chronic periodontitis in our dental practice. Nearly all remaining teeth in the upper and the lower jaw showed significant signs of progredi- ent chronical periodontitis, insuffi- cient root treatments and prosthetic suprastructures as well (Fig. 1). The medical history of the patient was without any significant pathological findings. Diagnostic procedures In cases of long-term edentulism, the dental surgeon is almost always con- fronted with a reduced bone volume, representing both a major challenge and a significant demand for the use of diagnostic imaging methods prior to augmentation and implant treatment. Conventional X-ray im- ages contain only a two-dimensional information concerning the vertical Fig. 3: Pre-operative clinical aspect of the anterior alveolar ridge. Fig. 4: After elevation of the mucoperi- ostal flap, the sharp-edged alveolar ridge becomes visible. Fig. 5: Preparation of the osseousgraft with the microsaw. Fig. 6: Detachment of the graft with a chisel. research Titanium and its alloys in dental implantology case report Rehabilitation of edentulous patients industry Digital workfl ow: From planning to restoration Fig. 1: Pre-operative panoramic X-ray: poor periodontal and prosthetic conditions. Figs. 2a & b: Pre-operative CBCT: aspect of the extremely horizontally resorbed alveolar ridges of the anterior part of the mandible. height of the alveolar bone. There- fore, they represent an insufficient method for the appreciation of the horizontal bony dimensions.4 In comparison, three-dimensional (3- D) diagnostic tools like cone beam computed tomography (CBCT) offer the advantage of the visualisation of the so called ‘z-axis’, representing the bone volume in the horizontal, i.e. bucco-lingual dimension of the alveolar crest respectively. A proper treatment planning and the use of 3-D diagnosis are therefore crucial parameters for a predictable and sustainable final treatment outcome in implant therapy, especially in pa- tient cases with severe resorption of the jawbone, like in our presented patient case. The oral examination and the CBCT- Scan (SCANORA, SOREDEX, Schutter- wald, Germany) revealed a distinct bone resorption in the lower jaw, showing a more pronounced hori- zontal atrophy in the anterior part of the mandible (Figs. 2 & 3). According to the clinical measurements and the values of the 3-D CBCT scan, the interforaminal vertical bone height was between 22.0–25.0 mm. The hor- izontal bone volume amounted to between 1.0–3.0 mm in the implan- tation zone. The CBCT–Scan revealed a horizontal crestal bone thickness of 1.09 mm in region 32, and 1.74 mm in region 44. Treatment planning and aug- mentation procedure After patient-consultation, we opt- ed for a twostage surgery with an intraorally harvested autogenous bone-graft and a delayed implant treatment after a healing period of at least four months. As the vertical dimension of the implant region ap- peared to be sufficient enough for placement of implants with a stand- ard length, we decided to cut off 5.0 mm of the thin and sharp-edged al- veolar ridge by osteotomy, in order to create an autogenous lateral onlay bone-graft for horizontal augmen- tation in the anterior alveolar ridge. This protocol comprised in our view the advantage of the avoidance of donor morbidity, because the donor site was the receptor site as well. Af- ter creation and mobilisation of the mucoperiostal flap, the very thin and sharp edge of the atrophied alveolar crest became visible (Fig. 4). The os- teotomy of the bone was performed with a saw (Bone splitting system, Helmut Zepf Medizintechnik GmbH, Seitingen-Oberflacht, Germany; Fig. 5). Subsequently, the graft was detached from the anterior mandi- ÿPage D2