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20 I I report _ inferior alveolar nerve Fig. 7_Preparation of the buccal bony window with the cogged part of the Piezo device. Fig. 8_Preparation of the nerve. Fig. 9_The encircled nerve. Fig. 10_Post-implantation status. Fig. 11_Repositioning of the nerve. Fig. 12_Covering with a collagen membrane. Fig. 13_Status following prosthetic restoration. Fig. 14_X-ray control. implants3_2010 or paresthesia. Several studies have considered this risk. In his 1992 study Rosenquist12 demonstrated that 12 months later sensory disorders could not be observed in all 10 patients (26 implantations). Peleg’s10 2002 study did not show any permanent disorders either. Jensen7 quoted 10 % sensory dis- orders after 12 months. In 2005 Ferrigno3 reached the same results, and he also agreed with the fig- ure stated by Watzek 14 . The interesting retrospec- tive study by Kan9 1997 is the only one that com- pares both surgical techniques, the “displacement of the foramen” and the “lateralization of the in- ferioralveolarnerve”.Heanalyzed21surgeries(64 implantations) after 10 to 67 months. He found out that sensory disorders occurred significantly more often in cases of displacement of the fora- men(66.7 %)comparedtothelateralizationofthe nerve (33.3 %). These results show that in this regard, lateral- izationislessrisky.Theimplantsurvivalratestated intheabove-mentionedstudiesisbetween93.8 % and 100 %. Kan describes for example another probable complication, i.e. a fracture of the mandible at the operation site. The mandible is weakend by the removal of the buccal corticalis, and by the crestal implantation at the same time, and thus there is an increased risk of fracture. We observed temporary irritations of the men- tal nerve appearing as paresthesia in 90 % of our own patients. These irritations disappeared com- pletely within 8 weeks. _Clinical procedures Diagnosis Thorough clinical and radiological examina- tions are crucial preparations for this surgical procedure. In addition to the conventional OPG (panoramic radiography) (Fig. 2), a three-dimen- sional examination using CT (computer tomogra- phy) or DVT (digital volume tomography) images, and their evaluation with the appropriate soft- ware, is absolutely necessary. Therefore it is possi- ble beforehand to get a three-dimensional image of the route of the inferior alveolar nerve in the mandible. Figure 3 shows an evaluation using Med-3-D software. The positioning of the buccal bony window should be especially considered when planning thesurgery.Afterhavingpreparedthebuccalbony window and the implant cavity, it is of great im- portance to preserve enough bone in the buccal area of the implant, in order to guarantee suffi- cient primary stability. Fig. 11 Fig. 12 Fig. 8 Fig. 9 Fig. 10 Fig. 7 Fig. 14Fig. 13