Background: Titanium and titanium alloys are widely used for fabrication of dental implants. Since the material composition and the surface topography of a biomaterial play a fundamental role in osseointegration, various chemical and physical surface modifications have been developed to improve osseous healing. Zirconia-based implants were introduced into dental implantology as an altenative to titanium implants. Zirconia seems to be a suitable implant material because of its tooth-like colour, its mechanical properties and its biocompatibility. As the osseointegration of zirconia implants has not been extensively investigated, the aim of this study was to compare the osseous healing of zirconia implants with titanium implants which have a roughened surface but otherwise similar implant geometries. Methods: Forty-eight zirconia and titanium implants were introduced into the tibia of 12 minipigs. After 1, 4 or 12 weeks, animals were sacrificed and specimens containing the implants were examined in terms of histological and ultrastructural techniques. Results: Histological results showed direct bone contact on the zirconia and titanium surfaces. Bone implant contact as measured by histomorphometry was slightly better on titanium than on zirconia surfaces. However, a statistically significant difference between the two groups was not observed. Conclusion: The results demonstrated that zirconia implants with modified surfaces result in an osseointegration which is comparable with that of titanium implants.

Background: Osseointegration is crucial for the long-term success of dental implants and depends on the tissue reaction at the tissue-implant interface. Mechanical properties and biocompatibility make zirconia a suitable material for dental implants, although surface processings are still problematic. The aim of the present study was to compare osteoblast behavior on structured zirconia and titanium surfaces under standardized conditions. Methods: The surface characteristics were determined by scanning electron microscopy (SEM). In primary bovine osteoblasts attachment kinetics, proliferation rate and synthesis of bone-associated proteins were tested on different surfaces. Results: The results demonstrated that the proliferation rate of cells was significantly higher on zirconia surfaces than on titanium surfaces (p < 0.05; Student's t-test). In contrast, attachment and adhesion strength of the primary cells was significant higher on titanium surfaces (p < 0.05; U test). No significant differences were found in the synthesis of bone-specific proteins. Ultrastructural analysis revealed phenotypic features of osteoblast-like cells on both zirconia and titanium surfaces. Conclusion: The study demonstrates distinct effects of the surface composition on osteoblasts in culture. Zirconia improves cell proliferation significantly during the first days of culture, but it does not improve attachment and adhesion strength. Both materials do not differ with respect to protein synthesis or ultrastructural appearance of osteoblasts. Zirconium oxide may therefore be a suitable material for dental implants.

Sufficient vertical and lateral bone supply and a competent osteogenic healing process are prerequisities for the successful osseointegration of dental implants in the alveolar bone. Several techniques including autologous bone grafts and guided bone regeneration are applied to improve quality and quantity of bone at the implantation site. Depending on the amount of lacking bone one- or two-stage procedures are required. Vertical bone augmentation has proven to be a challenge particularly in terms of bone volume stability. This study focuses on the three dimensional vertical bone generation in a one stage procedure in vivo. Therefore, a collagenous disc-shaped scaffold (ICBM = Insoluble Collagenous Bone Matrix) containing rhBMP-2 (Bone Morphogenetic Protein-2) and/or VEGF (Vascular Endothelial Growth Factor) was applied around the coronal part of a dental implant during insertion. RhBMP-2 and VEGF released directly at the implantation site were assumed to induce the generation of new vertical bone around the implant. One hundred eight titanium implants were inserted into the mandible and the tibia of 12 mini pigs. Four experimental groups were formed: Control group, ICBM, ICBM + BMP-2, and ICBM + BMP-2 + VEGF. After 1, 4 and 12 weeks the animals were sacrificed and bone generation was investigated histologically and histomorphometrically. After 12 weeks the combination of ICBM + rhBMP2 + VEGF showed significantly more bone volume density (BVD%), a higher vertical bone gain (VBG) and more vertical bone gain around the implant (PVBG) in comparison to the control group. By using collagenous disc-shaped matrices in combination with rhBMP-2 and VEGF vertical bone can be generated in a one stage procedure without donor site morbidity. The results of the presenting study suggest that the combination of rhBMP-2 and VEGF applied locally by using a collagenous carrier improves vertical bone generation in vivo. Further research is needed to establish whether this technique is applicable in clinical routines.

Many reconstruction materials for orbital floor fractures have been described in the past including autologous bone transplants, resorbable polymers and titan meshes. So far evidence is missing which material is used successfully regarding indication and particular size of defect. Therefore the aim of this study was to evaluate which reconstruction technique produces best clinical outcome and least complications associated with indication. Retrospectively, surgical and ophthalmological data plus CT scans from a collective of 775 patients between 2005 and 2012 were analyzed. Furthermore included patients were sounded on satisfaction and potential problems postoperatively. Overall 593 patients offered full pre- and postoperative short-time data appropriate to inclusion criteria – of these 507 (85,5 %) underwent primary surgical treatment. Smallest average defect size was found in cases with no indication for surgical treatment (81 mm2), largest in cases indicating titanium mesh reconstruction (601.5 mm2). In 15 cases exact fragment reposition was possible without insertion of alloplastic material. Best clinical results obtained reconstruction using polydioxanone foil (PDS). 0.15 mm PDS-foil: 444 patients, reduced diplopia pre to postoperative 16 to 6 % (p < 0.01), ex- and enophthalmus < 2 % after surgery. 0.25 mm PDS-foil: 26 patients, reduced diplopia from pre- to postoperative 34,6 to 3,8 % (p < 0.01), postoperative exophthalmus rate was higher than preoperative (3,8 to 7,7 %). In comparison to reconstruction with PDS-foil a higher percentage of patients reconstructed with titanium meshes (n = 22) revealed no significant reduction of diplopia (45,5 to 31,8 %; p = 0.07). Furthermore 63 of all included patients agreed to complete a questionnaire on intermediate-term postoperative symptoms and surgical contentedness. Remarkably 50 % of the patients reconstructed with titanium meshes indicated foreign body sensations and cold feeling in the long-term. Short- and intermediate-term results of clinical outcome in our patients with surgical treated orbital floor fractures (i.e. diplopia, en- or exophthalmus) reveal that thin resorbable foils, particularly 0.15 mm diameter PDS-foil seem to generate best results referring to orbital floor defects with a size of 250 to 300 mm2. Study number 4222, year 2013, ethics committee of the medical faculty of the Heinrich Heine university of Duesseldorf.

Tissue engineering of bone and cartilage tissue for subsequent implantation is of growing interest in cranio- and maxillofacial surgery. Commonly it is performed by using cells coaxed with scaffolds. Recently, there is a controversy concerning the use of artificial scaffolds compared to the use of a natural matrix. Therefore, new approaches called micromass technology have been invented to overcome these problems by avoiding the need for scaffolds. Technically, cells are dissociated and the dispersed cells are then reaggregated into cellular spheres. The micromass technology approach enables investigators to follow tissue formation from single cell sources to organised spheres in a controlled environment. Thus, the inherent fundamentals of tissue engineering are better revealed. Additionally, as the newly formed tissue is devoid of an artificial material, it resembles more closely the in vivo situation. The purpose of this review is to provide an insight into the fundamentals and the technique of micromass cell culture used to study bone tissue engineering.

Mandible defects are conventionally reconstructed using titanium plates. However, titanium causes metallic artifacts which impair radiological imaging. This study aims at evaluating mechanical fatigue of radiolucent fiber-reinforced polyetheretherketone (f-PEEK), polyetheretherketone (PEEK), polyetherketoneketone (PEKK), and polyphenylsulfone (PPSU) polymer plates for mandible reconstruction. A total of 30 plates (titanium [n = 6], f-PEEK [n = 6], PEEK [n = 6], PEKK [n = 6], PPSU [n = 6]) were implanted in synthetic mandibulectomized polyurethane mandibles. Servo-pneumatic mechanical testing with cyclic application of 30–300 N at 3 Hz was conducted. Bite forces were 70% on the unresected and 30% on the resected side. Total number of cycles was set to 250,000. Testing was aborted in case of plate or screw failure. Axial load to failure was tested with a speed of 1 mm/s. Kruskal–Wallis and Dunn’s post hoc tests were used. Titanium, f-PEEK, and PEEK showed no failure in fatigue testing and PPSU (p < 0.001) failed against titanium, f-PEEK, PEEK, and PEKK. Titanium allowed the highest load to failure compared to f-PEEK (p = 0.049), PEEK (p = 0.008), PEKK (p < 0.001), and PPSU (p = 0.007). f-PEEK, PEEK, and PEKK withstood expected physiological bite force. Although titanium plates provided the highest fatigue strength, f-PEEK and PEEK plates showed no failure over 250,000 chewing cycles indicating sufficient mechanical strength for mandible reconstruction.