As a metal-free counterpart to titanium, zirconia-based ceramic implants have emerged as a charming alternative in the dental sector in recent years. If you compare the two materials with each other, they correlate excellently in terms of biocompatibility and osseointegration. Nevertheless, ceramic implants account for only about 5% of all implants manufactured on the world market. Many users are critical of the non-metallic material because of its would be lack of mechanical stability and its ageing behaviour. But are these prejudices justified, and could the worldwide share of ceramic implants increase further in the coming years? This article compares the latest studies and gives an overview of the advantages and disadvantages of zirconium dioxide-based implants.

Als metallfreies Pendant zu Titan haben sich Keramikimplantate auf Zirkoniumdioxidbasis in den vergangenen Jahren als charmante Alternative im zahnärztlichen Sektor herauskristallisiert. Vergleicht man die beiden Werkstoffe miteinander, korrelieren sie in puncto Biokompatibilität sowie Osseointegration exzellent miteinander. Dennoch machen keramische Implantate auf dem Weltmarkt nur etwa 5 % aller gefertigten Implantate aus. Viele Anwender stehen dem nichtmetallischen Material aufgrund angeblich mangelnder mechanischer Stabilität sowie eines schnelleren Alterungsverhaltens kritisch gegenüber. Doch sind diese Vorurteile gerechtfertigt und könnte der weltweite Anteil keramischer Implantate in den nächsten Jahren weiter steigen? Dieser Beitrag vergleicht neueste Studien und gibt einen Überblick der Vor- und Nachteile von Implantaten auf Zirkoniumdioxidbasis.

The aim of this prospective controlled study was to determine the validity of the mandibular cortical shape index (CI) on panoramic radiographs in distinguishing patients with osteoporosis as defined by the German Osteology Organization (Dachverbands der Deutschsprachigen Osteologischen Fachgesellschaften, DVO). The study group contained 50 patients (33 female, 17 male, mean age: 74.9 years), who had a high risk of osteoporosis. 50 young patients (33 female, 17 male, mean age: 37.9 years) with no anamnestic evidence of osteoporosis served as control. Three blinded observers evaluated panoramic views of the study and the control group in a mixed manner regarding the mandibular cortical shape index. The study group underwent bone mineral density measurement using dual energy X-ray absorptiometry and received a diagnosis according to the Organization's guidelines (normal, osteopenia, osteoporosis). The CI showed a high sensitivity of 72.2% and a high specificity of 93.9% with a highly significant predictive value (Chi-square = 22.96, p < 0.001), while the observer's agreement was moderate (kappa = 0.47). We concluded that patients with a cortical shape index of the category assessed as "severe" on non-standardised panoramic radiographs have a higher risk of suffering systemic osteoporosis. The CI in panoramic radiographs is a good screening tool, which could be implemented in the routine assessment of panoramic radiographs in elder patients.

OBJECTIVES:To mechanically evaluate the effect of transplantation of precultured preosteoblasts derived from autogenic adult mesenchymal stem cells (aMSC) for experimental sinus floor augmentation on primary dental implant stability in comparison with conventional augmentation procedures in rabbits.MATERIAL AND METHODS:After experimental sinus floor augmentation with a synthetic bone substitute, autogenous bone transplantation or osteoblast precursor cells, the primary stability of implants inserted in the edentulous part of the upper jaw of New Zealand White Rabbits was examined. Mechanical evaluation was performed by determination of insertion torque values (Osseocare(™) ), percussion testing (Periotest(™) ), resonance frequency analysis (Osstell(™) and scanning laser Doppler vibrometer) and measurement of extraction forces.RESULTS:Evaluation of mechanical properties with percussion testing and resonance frequency analysis with Osstell(™) revealed slightly higher primary stability of the stem cell group whereas the scanning laser Doppler vibrometer and measurement of pull-out forces showed no significant difference to the bone substitute group. Transplantation of autogenous bone graft resulted in the highest primary implant stability.CONCLUSIONS:The three examination modalities proved suitable for the determination of primary implant stability. The experimental maxillary sinus floor augmentation with precultured osteoblast precursor cells from autogenic stems cells clearly enhanced the primary stability of implants compared with the unaugmented sinus and lead to comparable primary mechanical properties to bone substitutes in rabbits. In comparison with the autogenous bone graft stability enhancement by stem cell transplantation declined.

Purpose: Microvascular fibula harvesting for osseous reconstruction is a valuable aid in maxillofacial surgery. We assessed whether the lateral and the medial harvesting techniques differed with respect to long-term donor-site morbidity.Materials and Methods: We conducted a retrospective cohort study of patients who had undergone free fibula harvesting at the University Medical Center Hamburg-Eppendorf, Hamburg, Germany, between 1987 and 2008. The primary predictor variable was the surgical approach. The primary and secondary outcome variables were the American Orthopaedic Foot & Ankle Society score and the result of the Short Form 36 Health Survey on quality of life, respectively. Other variables were age, gender, harvest length, operation time, and specific impairments and surgical complications. Statistical analysis was performed with SPSS, version 14.0 (SPSS, Chicago, IL); P < .05 was considered significant.Results: The 42 patients had a mean age of 55.5 years. The mean follow-up period was 81 months (range, 7-174 months). In the medial group, the mean American Orthopaedic Foot & Ankle Society score was 94.4 points and the total number of impairments was 34, as compared with 85.6 points and 46 impairments, respectively, in the lateral group. This tendency for less morbidity with the medial approach was only found in female patients. The Short Form 36 scores were not statistically different between the 2 surgical approaches.Conclusions: The medial approach led to less functional impairment of the foot and ankle. Our results support the medial approach as a viable alternative, especially in women, but only in cases when a skin paddle is not necessary. (C) 2012 American Association of Oral and Maxillofacial Surgeons J Oral Maxillofac Surg 70:2198-2204, 2012

PURPOSE:The surgical approaches for the open treatment of condylar process fractures have been controversial. In our study, we evaluated the morbidity of the transparotid approach during 2 years of follow-up. PATIENTS AND METHODS:A total of 48 patients with condylar process Class II and IV fractures according to classification of Spiessl and Schroll, were included in the present study. Of the 48 patients, 16 were female and 32 male. The patient age range was 16 to 79 years (average 36.52). All patients were treated using the transparotid approach, with rigid internal fixation using miniplates. Follow-up examinations were performed for a minimum of 6.5 months and a maximum of 25 months (average 12.16) after surgical treatment. At the follow-up examination, the patients completed the Mandibular Function Impairment Questionnaire, and the examiner completed the Helkimo index. X-rays taken before, directly after, and 6 months after surgery were compared. RESULTS:None of our patients had problems with wound healing; 2 patients developed a fistula of the parotid gland; and 4 patients developed palsy of the facial nerve that was completely reversible after 6 weeks. The results of the Mandibular Function Impairment Questionnaire and the Helkimo index revealed only a few subjective and objective problems after 6 months. CONCLUSIONS:The transparotid approach to condylar process fractures is most appropriate for strongly displaced Class II fractures. Especially for very old patients with dementia, for whom maxillomandibular fixation is contraindicated, this approach is very appropriate. Another benefit to this type of patient is the short operating time, with an average of 45 minutes.

Malignant tumors in the oral cavity are relatively rare. About 5% of all malignant growths in the body are localized in the oral cavity. The vast majority of oral malignancies are primary tumors with squamous cell carcinoma being the most frequent and sarcomas occurring very seldom. Secondary tumors caused by hematogenous spread arising from a tumor localized elsewhere in the body are extremely rare. About 1% of all oral cancers are metastases to the jawbones and the surrounding soft tissues. Metastases to the jaws are mainly caused by malignant tumors of the breast, lung, kidney, bone, and colon. They occur in the late state of the disease and are regularly detected by staging examinations including scintigraphy. Even more rare are metastases into odontogenic cysts. Odontogenic cysts include dentigerous cysts, periapical or radicular cysts, and the keratocysts-nowadays declared as keratocystic odontogenic tumor. The incidence of odontogenic cysts is about 10% to 15% of all oral biopsies and therefore general dentists are frequently faced with these types of lesions. The aim of this study was to review the literature regarding metastasis into odontogenic cysts and to further highlight this rare entity with the help of a clinical case.

Purpose: The results of primary bone grafting in terms of initial cleft width, existence or absence of a lateral incisor and sear formation in the donor area are compared. Methods: After primary osteoplasty with calvarian bone at an average age of 24 months (4-56 months) radiographic assessment was carried out in 31 patients with 40 alveolar clefts. The bone formation in the grafted area was assessed using dental radiographs taken at 66 months on average (13-114 months) after primary bone grafting. According to the Abyholm classification patients were assigned to 4 groups (indices I-IV) with indices I and II being rated as a success. Results: We observed success (indices I and II) in 76% and poor results (index IV) in 14%. The causes for the poor results were an alveolar cleft width of 11-12 mm in three cases, an extraction of a decayed deciduous tooth 17 months after bone grafting in one case and a traumatic transplant loss in another case. The non-existence of a lateral incisor and a broad cleft are related to poor results. Conclusion: Based on the results presented, primary bone grafting using calvarial bone seems to be a promising alternative in bridging narrow alveolar defects. This method allows early intervention at an age in which children do not recognize themselves as cleft patients. The preservation of the deciduous teeth is equally important regarding their functional stimulus for bone development. (C) 2009 European Association for Cranio-Maxillofacial Surgery

Objective. New approaches to enhance vertical bone regeneration in clinically relevant implant models are needed. Therefore, we analyzed the impact of recombinant human bone morphogenic protein 2 (rhBMP-2) on the healing of large buccal alveolar defects during osseointegration of transgingivally inserted implants.Study design. Twenty-four dental implants were inserted transgingivally in the mandibles of 6 labrador/golden retriever cross-bred dogs. Before implantation, a standardized buccal bone defect was created and refilled with either calcium phosphate as a carrier containing rhBMP-2 or calcium phosphate alone. Either ceramic abutments that enabled immediate implant loading or healing distance collars to prevent loading were mounted. Sixteen weeks after intervention, bone implant units were analyzed by radiofrequency analysis and histomorphometry.Results. In total, 14 implants (58.3%) were available for further analysis. The mean depth of the bone defects, the gain of regenerated bone, the vertical osseointegration of the implants, and the bone-to-implant contact in the newly formed bone were slightly greater in the rhBMP-2-containing samples. In contrast, the osseointegration in the preexisting bone was even superior within the non-rhBMP-2-treated specimen. However no differences were statistically significant.Conclusions. When rhBMP-2-conducted bone regeneration was compared with control samples, no significant differences of newly formed bone were found at the bone-implant interface. The amounts of rhBMP-2 applied do not seem suitable to enhance implant osseointegration in large buccal defects. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2009; 108: e3-e12)

Purpose: The improvement of the ischaemic tolerance of myocutaneous flaps is of clinical importance and hence the subject of numerous investigations. Methods: In an attempt to increase the ischaemic tolerance, 20 myocutaneous flaps (rectus abdominis muscle) in pigs were elevated and perfused with various, established solutions prior to the onset of ischaemia. The flaps were elevated, utilizing the superior epigastric vessels as the pedicle. Ten flaps were flushed with the University of Wisconsin solution, five with the Euro-Collins solution and the last five with a Ringer-Lactate solution, prior to the 6 h long, normothermic ischaemia. On the day of operation, the first, third, fifth, seventh and tenth postoperative day clincical examinations and thermography were performed as well as biopsies. Additionally, on the tenth postoperative day, the rate of necrosis was determined morphometrically as the average of three measurements. Results: Ten days after surgery, the flaps pretreated with the University of Wisconsin solution displayed a vital surface area of 89%, the Euro-Collins solution 23% and the Ringer-Lactate solution 14%. Histologically, muscle tissue proved to be more susceptible to ischaemia than skin. Conclusion: Regarding the rectus abdominis flap in a pig model, the University of Wisconsin solution proved superior in the prevention of ischaemic injury compared with the Euro-Collins solution and Ringer Lactate. In accordance with the literature, muscle tissue proved to be more susceptible to ischaemia than skin in our study. (C) 2008 European Association for Cranio-Maxillofacial Surgery

Clear-cell odontogenic carcinoma (CCOC) is a rare neoplasm of the jaws, as first described by Hansen et al in 1985. 1 Hansen L.S. Eversole L.R. Green T.L. et al. Clear cell odontogenic tumor—A new histologic variant with aggressive potential. Head Neck Surg. 1985; 8: 115 Crossref PubMed Scopus (122) Google Scholar Located in the mandible and maxilla, its histologic appearance suggests an odontogenic origin. The CCOC, formerly termed clear-cell odontogenic tumor, was included in the World Health Organization (WHO) classification of odontogenic tumors in 1992. 2 Kramer I.R.H. Pindborg J.J. Shear M. WHO Histological Typing of Odontogenic Tumors. (ed 2). Springer, New York1992 Crossref Google Scholar This tumor was defined as a benign neoplasm with a capacity for locally invasive growth, and was considered more aggressive than ameloblastoma. Different authors later described cases of CCOC with the potential for distant metastasis. 3 Bang G. Koppang H.S. Hansen L.S. et al. Clear cell odontogenic carcinoma: Report of three cases with pulmonary and lymph node metastases. J Oral Pathol Med. 1989; 18: 113 Crossref PubMed Scopus (60) Google Scholar , 4 Brinck U. Gunawan B. Schulten H.J. et al. Clear-cell odontogenic carcinoma with pulmonary metastases resembling pulmonary meningothelial-like nodules. Virchows Arch. 2001; 438: 412 Crossref PubMed Scopus (37) Google Scholar , 5 Duffey D.C. Bailet J.W. Newman A. Ameloblastoma of the mandible with cervical lymph node metastasis. Am J Otolaryngol. 1995; 16: 66 Abstract Full Text PDF PubMed Scopus (32) Google Scholar Reichart and Philipsen 6 Reichart P.A. Philipsen H.P. Revision der WHO-Klassifikation odontogener Tumoren von 1992. Mund Kiefer Gesichts Chir. 2003; 7: 88 Crossref PubMed Scopus (10) Google Scholar proposed a revision of the classification of odontogenic tumors in 2003, clearly considering the clear-cell odontogenic tumor as a carcinoma.

Object: The aim of our study was to demonstrate the image quality of the new device using human cadavers, extending the horizon of available imaging modalities in forensic medicine.Materials and methods: Six human cadavers were examined, revealing C-arm data sets of the head, neck thorax, abdomen and pelvis. High-resolution mode was performed with 500 fluoroscopy shots during a 190 degrees orbital movement with a constant tube voltage of 100 Wand a current of 4.6 mA. Based on these data sets subsequent three-dimensional reconstructions were generated.Results: Reconstructed data sets revealed high-resolution images of all skeletal structures in a near-CT quality. The same image quality was available in all reconstruction planes. Artefacts caused by restorative dental materials are less accentuated in CBCT data sets. The system configuration was not powerful enough to generate sufficient images of intracranial structures. Conclusion: After the here-demonstrated encouraging preliminary results, the forensic indications that would be suitable for imaging with a 31) C-arm have to be defined. Promising seems the visualization local limited region of interest as the cervical spine or the facial skeleton. (C) 2007 Elsevier Ireland Ltd. All rights reserved.

Purpose: Since the first harvesting of a microsurgical fibula in 1974 by Ueba and in 1975 by Taylor, using the fibula for osseous reconstruction has proven to be a valuable approach. The harvesting technique, which has been refined by subsequent investigators, has become increasingly standardized, today providing a clear, reproducible method. The procedure involves elevating the fibular graft from lateral, choosing the shortest route to reach the fibula. One disadvantage of this approach is that the bone often obstructs visualization of the vascular pedicle, which lies medially, promoting unintentional injury. In addition, this method is associated with some donor site morbidity, prompting further investigations into accessing the fibula. Here we present an alternative approach for harvesting the fibula and highlight the pros and cons of each approach.Patients and Methods: Between 1999 and 2006, a total of 38 microsurgical (23 for the mandible, 9 for the extremities, and 6 for the maxilla) fibula grafts were harvested through the medial approach.Results: In all cases, the patency of the posterior tibial, peroneal vessels, and the tibial nerve could be visualized. Two flaps failed (both mandible, for a success rate of 94.7%). No ischemic or wound healing complications of the lower limb were observed.Conclusions: The medial approach for harvesting the fibula is a feasible alternative to the lateral approach and provides the surgeon with a comparable likelihood of success. If for some reason access from the lateral approach is contraindicated, then the medial route should be considered. (c) 2008 American Association of Oral and Maxillofacial Surgeons.

Introduction: Fibula, ilium and scapula are the preferred donor areas for vascularised bone grafts. For secondary mandibular reconstruction, however, compromises often have to be made as a result of the poor quality of the covering soft tissue and recipient vessels especially in irradiated patients. Callus distraction osteogenesis is a complementary method for optimising the intermaxillary relationship and the facial profile from an aesthetic point of view. Materials and methods: Thirteen distractions were performed in seven patients following microsurgical mandibular reconstruction over a period of 4 years, all by the same surgeon. Intra-oral distraction devices were predominately applied. After a 7-day healing period, the callus distraction was begun, involving two advisements per day of 0.5 mm each. The distraction devices were removed after a consolidation phase of 4-5 months. Results: Ten of the 13 distractions were uneventful with an average bone lengthening of 20 mm, retained after a follow-up time of 6-47 months (average 27 months). The intermaxillary relationship and the facial profile were improved in all cases. Distraction plate fractures, screw loosening or absence of new bone formation were the complications encountered in the other three patients. Conclusion: Regarding the high complication rate, a successful outcome cannot be expected with greater certainty. Thus the indication should be stringent when including this procedure within the possible treatment alternatives available to the clinician. (C) 2008 European Association for Cranio-Maxillofacial Surgery.

Aim: To investigate whether a multidirectional, angular stable osteosynthesis system is suitable for the treatment of mandibular fractures and to compare it with well established available systems. Material and methods: Following preliminary testing in an animal model, the multidirectional angular stable system TiFix 2.3 obtained from Litos (Hamburg, Germany) was utilised for internal fixation of 39 mandibular fractures. These involved four symphyseal fractures, 17 parasymphyseal, 16 of the angle of the mandible and two comminuted fractures. The surgical and postoperative course was closely scrutinised. Radiographs were taken after 6 months and all plates removed under local anaesthesia. Photographs were taken intraoperatively and the plates and surrounding soft tissues were salvaged for histological analysis. Additionally, these operations were compared with treatment of equivalent fractures which were treated with conventional, non-angular stable systems. The relative costs have also been evaluated. Results: In 33 of the 39 fractures one TiFix plate sufficed for osteosynthesis. The plate most often used was a 2-hole plate which was applied in 25 (55.5%) fractures, followed by the 4-hole plates used in 16 (35.5%) fractures. In two comminuted fractures, four 6-hole plates were used (9%). In 17 patients the operation lasted less than 30 min, in 20 patients less than 60 min, in two less than 120 min. In all cases, the operations were shorter, and due to the plates' dimensions fewer screws had to be used, thus reducing the costs. Discussion: This angular stable system enabled reduction of the amount of the implant material. Also reduced were the operation time and the cost of the procedure. Furthermore, in the future it will allow smaller access incisions and better preservation of the soft tissue integrity. (c) 2008 European Association for Cranio-Maxillofacial Surgery.

Background: Following open reduction, internal fixation of fractures of the mandible is predominantly achieved using plates and screws. Today, a multitude of osteosynthesis systems are available on the market. One therapy modality, primarily developed for orthopaedic surgery, is using angular stable osteosynthesis plate systems. The dominating principle of these is the bond between screw and plate following insertion. This principle of an "internal fixateur" results in a more stable fixation of the fragments associated with less compression of the bone surfaces. Material: A new multidirectional osteosynthesis system (TiFix = Smartlock, Hamburg Germany) was modified to fit the maxillofacial region and compared with four other well established osteosynthesis systems developed by Mondial, Medicon, Synthes, Leibinger-Stryker, one of these (Unilock by Synthes) being also angular stable. The resistance to deformation in varying directions was investigated following fixation in four different materials. Results: The TiFix system proved more resistant to deformation even when mounted with fewer screws than the non-angular stable systems. Conclusion: This system results in greater stability even when fewer screws are used. For the clinician this means smaller access incisions, less soft tissue trauma, better aesthetic results, decreased duration of operation and a reduction of costs. (c) 2008 European Association for Cranio-Maxillofacial Surgery.

Purpose: This study investigated 3-dimensional (3D) imaging with intraoperative cone beam computed tomography (CBCT) in major mandibular reconstruction procedures.Patients and Methods: The study group was comprised of 125 patients (83 males, 42 females) admitted for surgical treatment of the mandible. The patients ranged in age from 3 months to 91 years (average age, 40.72 +/- 22.843 years). Surgical procedures of the mandible were subdivided into repair of body fractures (17 patients), angle fractures (21 patients), condylar fractures (14 patients), and multiple fractures (30 patient). In addition, the study group included 21 patients undergoing orthognatic surgery and 22 undergoing reconstructive surgery on the mandible. Intraoperatively, 3D images were generated with a mobile CBCT scanner (Arcadis Orbic 3D; Siemens Medical Solutions, Erlangen, Germany).Results: During open reduction of mandibular fractures, not all fracture sites can be readily exposed for direct visual control. For example, the lingual cortical bone of the mandible is difficult to assess intraoperatively. This structure and others can be effectively visualized using the 3D mode of CBCT. Furthermore, screw placement can be evaluated, specifically in insertions near the alveolar nerve. The intraoperative acquisition of the data sets is uncomplicated, and the image quality is sufficient to allow evaluation of the postoperative result in all cases.Conclusion: Intraoperative CBCT has proven to be a reliable imaging technique for providing visual control during major mandibular procedures. (c) 2008 American Association of Oral and Maxillofacial Surgeons.

The use of a combination of intraoperative cone-beam computed tomography (CBCT) and a navigation system via a spinal software platform for the navigated implantation of oral implants after microsurgical bone transfer is described. Intraoperative data sets were generated using Arcadis Orbic 3D (Siemens, Medical Solutions, Erlangen, Germany) and immediately transferred to the VectorVision(2) navigation system (BrainLAB, Feldkirchen, Germany) via the NaviLink interface. In two patients who underwent microsurgical bone transfer for midfacial reconstruction, implants were placed using intraoperatively acquired CBCT data sets for planning and navigated insertion. In both cases, successful realization of the planned implant sites was achieved by the guidance of the drill, leading to rehabilitation of both patients. CBCT data generated by mobile systems are sufficient for the planning of implant position, and can be used for navigated insertion using tools originally developed for spinal surgery.

Purpose: To investigate the susceptibility of implants to inflammation following autogenous bone transplantation and to evaluate whether various factors affect outcomes. Materials and Methods: This retrospective cross-sectional clinical investigation involved patients who were treated between the years 1994 and 1996. The donor site, mode of transplantation, primary disease, gender, smoking habits, and age were evaluated with respect to outcomes. Clinical and radiologic assessments were the basis for the classification into 3 categories: (1) no inflammation, (2) mucositis, and (3) peri-implantitis. Lost implants were also noted. The data were evaluated statistically to determine whether significant differences existed. Results: Forty-three patients (23 men and 20 women) were involved in this retrospective study. These patients received a total of 216 oral implants over a follow-up time of 8 to 10 years. Depending on the type of reconstruction, rates of peri-implant inflammation between 9% and 38% were observed. For mucositis, rates of 16.3% to 24.1% were seen, and 30% to 70.9% of sites showed no inflammation. Conclusion: High rates of soft tissue inflammation adjacent to implants were observed. The choice of donor site in conjunction with the mode of transplantation seemed to influence the development of peri-implant inflammation. The microsurgically reanastomosed fibula seemed most resistant to inflammatory processes, followed by the microsurgically reanastomosed iliac crest, free iliac crest, and free fibula. No significant differences could be observed for primary disease. These findings should be taken into consideration prior to surgery and when establishing individual recall systems. INT J ORAL MAXILLOFAC IMPLANTS 2008;23:1102-1108

The aim of this report was to demonstrate the practicability of a new imaging modality, which allows three-dimensional intraoperative imaging and verification of bone-graft position, and to compare it to the currently available imaging systems. The ARCADIS Orbic 3D, a C-arm-based cone-beam computed tomography scanner developed for intraoperative imaging, was used to examine a previously augmented sinus floor, in order to verify the height and width of the augmentation and to determine whether any of the autogenous and synthetic bone-substitute mixture had penetrated the sinus membrane. Visualization of the entire sinus was possible with the aid of multiplanar reconstructions. Data acquisition and processing took 5 min.