Patients treated consecutively in one center (Department of Oral- and Craniomaxillofacial Surgery, University Medical Center Freiburg). None of the patients showed systemic disease. Both patients did not take regular medication and were negative for alcohol, nicotine, and drug use. Bothe male patients (48 and 51 years of age) were not immunosuppressed, irradiated or received chemotherapy. Written informed consent was obtained from the patient for publication of this case report and accompanying images. An ethic committee approval and consent was not necessary. This case report was performed in accordance with the Helsinki Declaration of 1964, as revised in 2013. Both patients lost their teeth several years before implant placement. The reason for extraction was not evaluable since both patients were referred for grafting and implant placement.

Surgery for bone augmentation and implant placement was performed under local anesthesia with Ultracain forte (Sanofi Aventis, Frankfurt, Germany) following a standard operation protocol. In the augmentation procedure, a crestal incision in the attached gingiva of the edentulous alveolar crest with one vertical releasing incision was used, after mobilization of the mucoperiosteal flap an autologous retromolar bone block was fixed on the occlusal part of the alveolar ridge. The bone block was secured with a microscrew (Modus 1.5, Medartis, Umkirch, Germany) and covered with a resorbable membrane (BioGide, Geistlich AG, Switzerland) as described previously [29]. The passively mobilized mucosa was closed with a running suture and secured with interrupted sutures (5-0 Monocryl, Ethicon, Norderstedt, Germany).

All implants were inserted with the same recommended torque of <35 Ncm. A standard oral antibiotic regimen was not applied after implant placement.

Both patients were clinically evaluated after one, ten and thirty days. All bone grafting procedures and implant placements were performed by two experienced surgeons (KN and SG). Oral radiographic examinations (orthopantomograms) were performed before and one day after the surgical procedure.