Antiresorptive Medikamente wie beispielsweise Bisphosphonate oder Denosumab sind in der Behandlung von Patienten sowohl mit Osteoporose als auch mit onkologischen Grunderkrankungen von hoher Bedeutung. Indem sie in den Knochenstoffwechsel eingreifen, tragen sie dazu bei, sogenannte skelettbezogene Ereignisse (z. B. Knochenbrüche), Schmerzen und lange Krankenhausaufenthalte zu reduzieren sowie die Lebensqualität von Patienten nachweislich zu verbessern. Durch ihre Bindung an das Kalzium des Knochens reichern sich die oral und intravenös verabreichten Bisphosphonate im Knochen an und es dauert eine gewisse Zeit, bis die Medikamente ihre volle Wirkung entfalten können. Einmal am Knochen gebunden, liegt dafür die Halbwertszeit bei über 10 Jahren. Der Antikörper Denosumab hingegen wirkt direkt nach der subkutanen Gabe an den für den Knochenauf- und abbau verantwortlichen Zellen und hat mit ca. 1 Monat eine wesentlich kürzere Halbwertszeit. Während antiresorptive Medikamente im Skelettknochen zu dessen Stabilisierung beitragen und das Wachstum von Knochenmetastasen hemmen, kann es im Bereich der Kieferknochen als seltene und unerwünschte Nebenwirkung zum Absterben des Knochens, zu einer sogenannten Antiresorptiva-assoziierten Kiefernekrose („Antiresorptive drug-related osteonecrosis of the jaw“, AR-ONJ) kommen. Diese erstmals im Jahre 2003 beschriebenen Therapiefolge kann zu großflächigem Verlust von Knochen und in der Folge zum Verlust von Zähnen führen und somit die Lebensqualität der Patienten verschlechtern.

Purpose: Intraoral bone blocks from the external oblique are the gold standard for alveolar ridge bone grafting, but the limited amount of available bone limits their use for larger defects. The objective of this study was to compare whether different graft designs of intraoral bone blocks could affect the amount of bone gain. Materials and Methods: In this in vitro study, 20 pig jaws were used to harvest bone blocks and subsequently augment single-wall bone defects. Each bone graft was first used as a full block, and then the same block was divided lengthwise into two blocks, with one block fixed at a distance as a cortical shell and the second block particulated to fill the gap between graft and bone. Three stereolithographic (STL) files (pre-OP, full block, split block) were generated using an intraoral scanner. All STL files were evaluated for volume gain and horizontal bone dimensions. Results: A mean volume gain of 0.36 cm2 (SD: 0.09) was achieved for the full block and 0.78 cm2 (SD: 0.14) for the split block using the same block. The difference was statistically significant (P < .0001). A mean horizontal bone gain of 4.37 mm (SD: 0.93) was achieved with a full block and 5.77 mm (SD: 0.85) with the shell technique (P < .0001). Conclusion: With the same amount of bone removed, first as a full block and then as a split block, the split-block technique achieved a significantly higher bone gain compared with the full-block design. Keywords: autogenous bone, bone augmentation, bone blocks, bone regeneration, graft design, intraoral bone graft

Bei einer verspäteten Diagnose oder Behandlung kann die antiresorptiva-assoziierte Kiefernekrose (AR-ONJ) einen komplikationsträchtigen und behandlungsintensiven Verlauf zeigen. So besteht insbesondere die Gefahr, dass es bei betroffenen Patienten zu einem großvolumigen Verlust von Kieferabschnitten kommen kann. Deshalb sollten die Vorbeugung, Früherkennung und Therapie einen hohen Stellenwert haben und keinesfalls aufgeschoben werden. Die bildgebende Diagnostik ist in der aktuellen Falldefinition und Klassifikation der AR-ONJ nur zum Teil berücksichtigt. Bei zunehmenden Fällen an Patienten mit einer Kiefernekrose ohne freiliegenden Knochen rückt die bildmorphologische Differenzialdiagnostik aber immer mehr in den Vordergrund. Mangels fehlender Evidenz gibt es trotz gehäufter röntgenologischer Merkmale noch keine pathognomonische, bild-morphologische Merkmalkonstellation, die die klare Diagnose einer AR-ONJ zulässt oder ausschließt. Ziel des Artikels ist es, einen Überblick über die derzeitige Bedeutung der Bildgebung in der Vorbeugung, Diagnostik und Therapieplanung von AR-ONJ zu geben und deren Limitation, aber auch Potenzial für die Zukunft aufzuzeigen. Keywords: Antiresorptiva-assoziierte Kiefernekrose (AR-ONJ), Definition, Klassifikation, Bildgebung, Bildmorphologie, Panoramaschichtaufnahme, Digitale Volumentomografie

Purpose: The use of short implants can reduce the need for augmentative procedures prior to implant placement and, thus, morbidity and treatment time for patients with severely atrophied alveolar ridges. However, the inevitably less favorable crown-to-implant ratio is often associated with higher implant failure rates and greater marginal bone loss. The aim of this study was to evaluate the long-term survival and success rates of short implants in severely atrophic alveolar ridges retaining restorations on these short implants only. Materials and Methods: In this study, 8-mm and 9-mm implants were inserted in atrophic alveolar ridges according to the manufacturer's protocol for the respective bone quality and loaded after 3 months of healing. Prosthetic restorations were supported only by short implants (not in combination with longer implants). After a mean observation period of 10.1 years (± 1.9 years), all patients were re-examined clinically and radiographically. Results: In this study, fifty-two 8-mm and 9-mm implants were placed in 14 patients. After 10.1 years, no implants and suprastructures had been lost. A mean marginal bone loss of 0.3 mm (± 0.4 mm) was recorded. According to the Albrektsson criteria, all implants were successful; with respect to the more rigorous Karoussis et al criteria, four implants failed. Conclusions: The results of this long-term study suggest that the use of short implants results in marginal bone resorption and failure rates similar to those for longer implants. The higher crown-to-implant ratio did not seem to have any negative influence on implant success in this study. Keywords: bone atrophy, dental implants, implant success, implant survival

Purpose: To accurately accomplish the drilling of an implant socket, the use of image-guided navigation has become an option. The aim of this study was to evaluate the 3-dimensional (3D) accuracy of navigation-guided drilled holes. Materials and Methods: Laboratory accuracy measurements were obtained on an acrylic resin model with standardized target holes drilled by a computerized numerical control machine. The model was scanned by a multislice computerized tomography scanner and registered with fiducial marker-based algorithms. Navigated drillings were performed using an optical navigation system based on passive marker technology. Coordinates of drilled holes were determined by a 3D-digitizer probe, and accuracy was assessed for all 5 degrees of freedom using a computer-aided design system (Pro/Engineer). Results: A total of 240 drillings were evaluated. Mean registration error was 0.86 mm (SD 0.25 mm). Target point deviation between preplanned and actual drill starting point was 0.95 mm (SD 0.25 mm). The deviation in terms of full length was 0.97 mm (SD 0.34 mm), and mean angular deviation on the coronal and sagittal planes was 1.35 degrees (SD 0.42 degrees). Discussion: The accuracy of image-guided navigation depends on imaging modalities, patient-to-image registration procedures, and instrument tracking. The technical accuracy and the navigation procedure, as evaluated in the study presented, seem to be of minor influence. Conclusion: The data obtained by this in vitro study demonstrate that the accuracy of navigation-based drilling may be sufficient for clinical practice, particularly in terms of the transferability of preplanned trajectories. However, in vivo clinical trials need to be performed to evaluate the clinical accuracy and treatment quality of navigation-guided interventions.

Spontaneous necrotising soft tissue lesions of the face can be differentiated into necrotising cellulitis, necrotising fasciitis and myonecrosis. Each type can be caused by a single or a variety of different agents. Early recognition and adequate management are mandatory in order to reduce mortality as many of these lesions are rapidly progressive infections causing extensive necrosis of the subcutaneous tissues followed by gangrene of the skin and systemic toxicity. This paper reports about a case of a rarely seen spontaneous necrotic soft tissue lesion of the face caused by the Mucormycosis causing agent Absidia Corymbifera and highlights the management of it. Keywords: Mukormykose, nekrotisierende Läsion, Haut, plastische Chirurgie

A case of a 68-year-old man is described who was referred to our department for further treatment of a malignant hemangiopericytoma of the left maxillary sinus. The referral diagnosis was made through an incisional biopsy. After angiographic verification of a highly vascularized tumour, embolisation of the left maxillary artery was performed. Further surgical treatment consisted of a hemimaxillectomy, partial resection of the orbital floor and removal of the ethmoidal cells. The histopathological examination of the removed tumour revealed a cellular infiltrate of spindle-shaped cells in a fibromyxoid stroma containing inflammatory cells consisting of lymphocytes, plasma cells and macrophages. The spindle-shaped cells expressed vimentin and a-smooth muscle actin positive immunophenotypes. Considering the histological features the initial diagnosis of a malignant hemangiopericytoma was withdrawn and the diagnosis of an inflammatory myofibroblastic tumour was made. In view of the changed diagnosis the initially planned exenteration of the left orbit did not have to be performed. This case report shows that an incisional biopsy remains problematic with regard to an accurate diagnosis of spindle-celled soft tissue tumours with overlapping morphological features and different clinical behaviour. In order to avoid unnecessary impairment of quality of life the treatment should not be performed too aggressively until the definitive histological diagnosis has been made on the removed tumour. Keywords: spindle-celled soft tissue tumour, malignant hemangiopericytoma, inflammatory myofibroblastic tumour, maxillary sinus

Ziel dieser Untersuchung war die Evaluation der mechanisch-physikalischen Eigenschaften mehrerer handelsüblicher konfektionierbarer Mundschutztypen. Hierzu wurden unter Einsatz eines speziell entwickelten Studienmodells die Dämpfungseigenschaften sowie die Kraftfortleitung bei Verwendung von sechs verschiedenen Mundschutzschienen gemessen. Die Messwerte bei mit laborgefertigten und selbst anzupassenden Mundschutzbehelfen versehenen Zähnen wurden mit denen ungeschützter Zähne in Beziehung gesetzt. Hierbei konnte festgestellt werden, dass das individuelle Dämpfungsverhalten in direkter Korrelation mit der Materialstärke steht. Die Kraftverteilung wird durch die Rigidität des Mundschutzbehelfs bestimmt. Die untersuchten selbst anzupassenden Behelfe erzielten im Vergleich zu den laborgefertigten Behelfen ähnlicher Materialstärke sowohl bezüglich des Dämpfungsverhaltens als auch in Hinsicht auf die Verteilung der einwirkenden Kräfte signifikant schlechtere Ergebnisse (p 0,01). Keywords: Mundschutzschiene, Zahntrauma, Prophylaxe, Sportverletzungen

In a retrospective study, Kaplan-Meier implant survival analyses were conducted on 883 patients with 1,964 implants of various systems placed, followed up, documented, and statistically evaluated at an oral surgery and dentistry practice between January 1981 and January 1997. The goal of this study was to evaluate the success of osseointegrated implants of the Brånemark, Frialit-1 (Tübinger Implant), Frialit-2, and IMZ systems and Linkow blade implants. For all systems, mandibular implants were generally more successful than maxillary implants. The preprosthetic loss rate was 1.9%, and 4.3% of implants were lost after prosthetic treatment. The lowest loss rates were seen with implants in intermediate and distal extension spaces and with single-tooth replacements using IMZ, Frialit-2, and Brånemark implants. In edentulous arches, implants of the IMZ and Brånemark systems had the lowest failure rates. Keywords: dental implants, longitudinal study, long-term results