Comparison of allogeneic and autogenous bone grafts for augmentation of alveolar ridge defects-A 12-month retrospective radiographic evaluation.

OBJECTIVES: The aim of this study was to compare three-dimensional alterations following the use of autogenous versus allogeneic onlay grafts for augmentation at single tooth defects. MATERIALS AND METHODS: Alveolar bone width at specific implant sites were assessed using sagittal and cross-sectional CBCT images prior grafting and at three subsequent time points. Twenty-one patients received autogenous bone blocks harvested from the retromolar region and another 21 patients received freeze-dried cancellous allogeneic bone blocks. RESULTS: The vertical and horizontal dimensions did not significantly differ between autogenous and allogeneic bone grafts at any time point. In addition, there were no statistically significant differences in graft remodeling rates between autogenous (mean shrinkage rate after 12 months: 12.5% ± 7.8%) and allogeneic onlay grafts (mean shrinkage rate after 12 months: 14.4% ± 9.8%). CONCLUSIONS: Freeze-dried cancellous allogeneic bone blocks showed equivalent volumetric shrinkage rates as autogenous bone blocks when used for treating circumscribed bone defects classified as Type-II to Type-IV according to the ITI-treatment guide categories. Therefore, it is not necessary to over-contour the alveolar ridge when using allogeneic blocks for treating single tooth defects, but to apply the same procedure as when using autogenous blocks.

Long-lived murine osteocytes are embodied by craniofacial skeleton in young and old animals whereas they decrease in number in postcranial skeletons at older ages.

BACKGROUND: Osteocytes are engaged in life-enduring processes such as bone remodelling, fracture healing or osseointegration of implants. Over age, ossification processes and regenerative capacity can greatly differ in mandible and femur. OBJECTIVE: Mesenchymal stem cells from cranial and postcranial bones are of different embryologic origin. This may be the reason why the regenerative capacity differs between cranial and postcranial bones in old patients. It was hypothesised that different ageing patterns, reflected by osteocyte density, lacunar density and osteoid formation, exist between murine mandibles and femurs. MATERIAL AND METHODS: Mandible and femur of young (4 months) and old (34-36 months old) male C57Bl/6 mice were histologically investigated to determine the number of lacunae occupied with osteocytes. Osteoid formation was revealed by Masson-Goldner staining, and the spatial distribution of BMP-2 synthesis was examined. RESULTS: Over lifetime, the number of lacunae occupied with osteocytes only showed a modest decrease in mandibular bone (old 85.63%/young 91.12%) while greatly diverging in the femur (old 55.99%/young 93.28%). In equal measure, old femur exhibited less osteoid formation and decreased BMP-2 expression. CONCLUSION: Tissue-specific conduct of bone ageing is moulded by osteocytic activities, which was found to vary between postcranial and craniofacial skeleton. The latter harbours long-lived osteocytes also in old animals which assures lifelong bone integrity. Preliminary concurring findings from a human cadaver, also presented in this contribution, provided a rationale for recommending the translatability to humans.

Comparison of morbidity-related parameters between autologous and allogeneic bone grafts for alveolar ridge augmentation from patients' perspective-A questionnaire-based cohort study.

INTRODUCTION: Alveolar ridge augmentation is often required before dental implant placement. In this context, autologous bone grafts are considered the biological gold standard. Still, bone block harvesting is accompanied by some serious potential disadvantages and possible complications, such as pain, bleeding, and nerve irritation. Several studies aimed to compare autologous to allogeneic bone grafts concerning bone quality and implant survival rates; this is the first prospective study analyzing and comparing morbidity-related parameters after alveolar ridge augmentation using autogenous and allogeneic bone blocks from patients' perspective. METHODS: Using a questionnaire, 36 patients were asked to evaluate the surgery as well as the post-operative period concerning pain, stress, sensibility deficits, satisfaction with, and consequences from the surgery as well as the preferred procedure for future alveolar ridge augmentations. RESULTS: No significant differences were shown regarding stress and pain during and after surgery, whereas the rate of nerve irritations was twice as high in the autologous group. The swelling was significantly higher in patients with autologous bone blocks (p = 0.001). Nevertheless, the overall satisfaction of patients of both groups was very high, with over 8/10 points. CONCLUSIONS: The swelling was the main reason for patients' discomfort in both groups and was significantly higher after autologous bone augmentation. Since this side effect seems to be a highly relevant factor for patients' comfort and satisfaction, it needs to be discussed during preoperative consultation to allow shared decision-making considering the anticipated morbidity.

Human bone marrow hosts polyfunctional memory CD4+ and CD8+ T cells with close contact to IL-15-producing cells.

Recently, a key role in memory T cell homing and survival has been attributed to the bone marrow (BM) in mice. In the human BM, the repertoire, function, and survival niches of CD4(+) and CD8(+) T cells have not yet been elucidated. In this study, we demonstrate that CD4(+) and CD8(+) effector memory T cells accumulate in the human BM and are in a heightened activation state as revealed by CD69 expression. BM-resident memory T cells produce more IFN-γ and are frequently polyfunctional. Immunofluorescence analysis revealed that CD4(+) and CD8(+) T cells are in the immediate vicinity of IL-15-producing BM cells, suggesting a close interaction between these two cell types and a regulatory role of IL-15 on T cells. Accordingly, IL-15 induced an identical pattern of CD69 expression in peripheral blood CD4(+) and CD8(+) T cell subsets. Moreover, the IL-15-inducible molecules Bcl-x(L), MIP-1α, MIP-1ß, and CCR5 were upregulated in the human BM. In summary, our results indicate that the human BM microenvironment, in particular IL-15-producing cells, is important for the maintenance of a polyfunctional memory CD4(+) and CD8(+) T cell pool.

First Clinical Case Report of a Xenograft-Allograft Combination for Alveolar Ridge Augmentation Using a Bovine Bone Substitute Material with Hyaluronate (Cerabone® Plus) Combined with Allogeneic Bone Granules (Maxgraft®).

BACKGROUND: A patient had lost the first left maxillary incisor in the esthetic zone. METHODS: The defect in the alveolar ridge was reconstructed for an implant-supported restoration using a new xenogeneic bone substitute containing hyaluronate, which was used in combination with allogeneic bone granules. RESULTS: After three years of follow-up, the dental implant was stable and showed no signs of infection. CONCLUSIONS: This is the first case report with a long-term follow-up time of three years of a successful clinical application of a xenograft-allograft combination (cerabone® plus combined with maxgraft®) for alveolar ridge augmentation before dental implantation. Cerabone® plus offers volume stability, provides reliable and efficient structural support of the oral soft tissues in the augmented region (particularly crucial in the aesthetic zone), and preserves the alveolar ridge shape.

Mesenchymal stem cells show radioresistance in vivo.

Irradiation impacts on the viability and differentiation capacity of tissue-borne mesenchymal stem cells (MSC), which play a pivotal role in bone regeneration. As a consequence of radiotherapy, bones may develop osteoradionecrosis. When irradiating human bone-derived MSC in vitro with increasing doses, the cells' self-renewal capabilities were greatly reduced. Mitotically stalled cells were still capable of differentiating into osteoblasts and pre-adipocytes. As a large animal model comparable to the clinical situation, pig mandibles were subjected to fractionized radiation of 2 χ 9 Gy within 1 week. This treatment mimics that of a standardized clinical treatment regimen of head and neck cancer patients irradiated 30 χ 2 Gy. In the pig model, fractures which had been irradiated, showed delayed osseous healing. When isolating MSC at different time points post-irradiation, no significant changes regarding proliferation capacity and osteogenic differentiation potential became apparent. Therefore, pig mandibles were irradiated with a single dose of either 9 or 18 Gy in vivo, and MSC were isolated immediately afterwards. No significant differences between the untreated and 9 Gy irradiated bone with respect to proliferation and osteogenic differentiation were unveiled. Yet, cells isolated from 18 Gy irradiated specimens exhibited a reduced osteogenic differentiation capacity, and during the first 2 weeks proliferation rates were greatly diminished. Thereafter, cells recovered and showed normal proliferation behaviour. These findings imply that MSC can effectively cope with irradiation up to high doses in vivo. This finding should thus be implemented in future therapeutic concepts to protect regenerating tissue from radiation consequences.

Risk Factors for Complications Following Staged Alveolar Ridge Augmentation and Dental Implantation: A Retrospective Evaluation of 151 Cases with Allogeneic and 70 Cases with Autogenous Bone Blocks.

Purpose: the aim of this study was to identify potential risk factors favoring complications by assessing the number and types of complications associated with allogeneic or autogenous bone blocks applied as onlay grafts for alveolar ridge augmentation prior to implantation. Methods: A retrospective chart review on the success of 151 allogeneic and 70 autogenous bone blocks in a cohort of 164 consecutive patients, who were treated over a period of 6 years by the same surgeon, was conducted. Statistical conclusions were based on ROC curves and multiple logistic regression models. Results: Complications were observed more frequently with autogenous bone blocks (14 out of 70 cases; 20%) compared to allogeneic bone blocks (12 out of 151 cases; 7.9%; p = 0.013). However, these complications were minor and did not impact the successful dental rehabilitation. In a multiple logistic regression model, the risk of a complication was increased by the use of an autogenous bone block (OR = 3.2; p = 0.027), smoking (OR = 4.8; p = 0.007), vertical augmentation above a threshold of 2.55 mm (OR = 5.0; p = 0.002), and over-contouring (OR = 15.3; p < 0.001). Conclusions: Overall, the complication rate of ridge augmentations carried out with autogenous or allogeneic bone blocks was low. Despite previous recommendations, over-contouring and a vertical augmentation above a threshold of 2.55 mm should be avoided.

The allogeneic shell technique for alveolar ridge augmentation: a multicenter case series and experiences of more than 300 cases.

PURPOSE: Allogeneic cortical bone plates (CP) might be used for alveolar ridge augmentation as an alternative to autogenous grafts (AG) and bone substitutes (BS). We report about a multicenter case series and our experiences of more than 300 cases using CP and the shell technique for reconstruction of the alveolar process to illustrate surgical key steps, variations, and complication management. METHODS: Different types of alveolar ridge defects were augmented using the shell technique via CP. The space between the CP and the alveolar bone was filled with either autogenous or allogeneic granules (AUG, ALG) or a mixture of both. Implants were placed after 4-6 months. Microscopic and histological assessments were performed. In addition, space filling using AUG, ALG and bovine BS was discussed. RESULTS: Scanning electron microscopy demonstrated the compact cortical structure of CP and the porous structure of ALG allowing micro-vessel ingrowth and bone remodeling. Histological assessment demonstrated sufficient bone remodeling and graft resorption after 4-6 months. In total, 372 CP cases and 656 implants were included to data analysis. The mean follow-up period was about 3.5 years. Four implants failed, while all implant failures were caused by peri-implantitis. Next, 30 CP complications were seen, while in 26 CP complications implant placement was possible. CP rehydration, stable positioning by adjusting screws, smoothing of sharp edges, and a tension-free wound closure were identified as relevant success factors. Space filling using ALG and a mixture of AUG/ALG resulted in sufficient bone remodeling, graft resorption and stability of the augmented bone. CONCLUSIONS: CP and the shell technique is appropriate for alveolar ridge augmentation with adequate bone remodeling and low complication rates. Allografts can prevent donor site morbidity and therefore may decrease discomfort for the patient.

In vivo investigation on connective tissue healing to polished surfaces with different surface wettability.

OBJECTIVES: Connective tissue in contact to transgingival/-dermal implants presents itself as tight scar formation. Although rough surfaces support the attachment they increase bacterial colonisation as well. In contrast to surface roughness, little is known about the influence of surface wettability on soft-tissue healing in vivo. We therefore investigated the influence of different surface wettabilities on connective tissue healing at polished implant surfaces in vivo. MATERIAL AND METHODS: Three polished experimental groups (titanium, titanium coated with hydrophobic nano-crystalline diamond (H-NCD) and titanium coated with hydrophilic nano-crystalline diamond (O-NCD) were inserted into the subcutaneous connective tissue of the abdominal wall of 24 rats. Animals were sacrificed after 1 and 4 weeks resulting in eight specimen per group per time point. Specimen were subjected to histological evaluation (van Giesson's staining) and immunohistochemistry staining for proliferating cell nuclear antigen (PCNA), fibronectin and tumour necrosis factor-alpha (TNF-α). RESULTS: Histological evaluation revealed dense scar formation at the titanium and H-NCD surfaces. In contrast, the connective tissue was loose at the O-NCD surface with a significantly higher number of cells after 4 weeks. O-NCD demonstrated a strong expression of PCNA and fibronectin but a weak expression of TNF-α. In contrast, the PCNA and fibronectin expression was low at the titanium and H-NCD, with a strong signal of TNF-α at the H-NCD surface. CONCLUSIONS: Hydrophilicity influences the connective tissue healing at polished implant surfaces in vivo positively. The attachment of connective tissue and the number of cells in contact to the surface were increased. Moreover, the inflammatory response is decreased at the hydrophilic surface.

Facial trauma: how dangerous are skiing and snowboarding?

PURPOSE: The aim of this study was to investigate maxillofacial injuries sustained in both skiing and snowboarding accidents and correlate injury mechanisms and patterns evaluating a large population. MATERIALS AND METHODS: Between 1991 and 2003, all patients with maxillofacial injuries due to skiing and snowboarding accidents (1,393 cases) were reviewed and statistically analyzed according to age, gender, type of injury, cause of accident, location of trauma, and associated injuries. RESULTS: Skiing accidents resulted in a total of 1,250 injuries, and snowboarding resulted in 143. In this study 686 skiers presented with 1,452 facial bone fractures and 80 snowboarders sustained 160 fractures of the face. Skiers had dentoalveolar trauma in 810 cases and 1,295 soft tissue injuries, whereas snowboarders had 88 dental injuries and 187 soft tissue lesions. Mechanisms of injury included 542 cases due to skiing and 85 falls due to snowboarding (a 1.79-fold higher risk for snowboarders). The gender distribution showed a male-female ratio of 3:1 in skiers and 5.5:1 in snowboarders. In both groups male patients were more prone to have a facial bone fracture than female patients. Snowboarders aged between 10 and 29 years had a 2.14-fold higher risk of sustaining a maxillofacial injury than skiers. CONCLUSIONS: In both groups facial bone fractures occurred more often in male patients, and they were more likely to result from falls and collisions with other persons. Young snowboarders had a higher risk of maxillofacial injuries (especially soft tissue lesions) than skiers, whereas for children and old persons, skiing posed a much higher risk. Wearing a helmet while skiing and snowboarding should be mandatory to prevent serious trauma to the head.

Customized allogeneic bone grafts for maxillary horizontal augmentation: A 5-year follow-up radiographic and histologic evaluation.

We report the histological evaluation of an individualized allogeneic bone block 5 years after alveolar ridge augmentation. The biopsy showed a well-vascularized lamellar bone with fatty incorporations without any avital allograft remnants. The presence of osteocytes, lining cells, macrophages, and blood vessels indicated a healthy and vital bone tissue.

The role of oxygen termination of nanocrystalline diamond on immobilisation of BMP-2 and subsequent bone formation.

Medical implants are increasingly often inserted into bone of frail patients, who are advanced in years. Due to age, severe trauma or pathology-related bone changes, osseous healing at the implant site is frequently limited. We were able to demonstrate that coating of endosseous implants with nanocrystalline diamond (NCD) allows stable functionalization by means of physisorption with BMP-2. Strong physisorption was shown to be directly related to the unique properties of NCD, and BMP-2 in its active form interacted strongly when NCD was oxygen-terminated. The binding of the protein was monitored under physiological conditions by single molecule force spectroscopy, and the respective adsorption energies were further substantiated by force-field-calculations. Implant surfaces refined in such a manner yielded enhanced osseointegration in vivo, when inserted into sheep calvaria. Our results further suggest that this technical advancement can be readily applied in clinical therapies with regard to bone healing, since primary human mesenchymal stromal cells strongly activated the expression of osteogenic markers when being cultivated on NCD physisorbed with physiological amounts of BMP-2.

EpCAM expression in squamous cell carcinoma of the oral cavity: frequency and relationship to clinicopathologic features.

This retrospective study was designed to investigate the prognostic significance of EpCAM expression in human oral squamous cell carcinoma on a long-term follow-up. EpCAM expression was examined immunohistochemically on a tissue microarray (TMA) of paraffin embedded tissue specimens from 77 consecutive patients who underwent surgical treatment for squamous cell carcinoma of the oral cavity in the period between 1980 and 1997 at the Department of Craniomaxillofacial and Oral Surgery, Innsbruck Medical University. High EpCAM expression was found in 17 (22.1%) of the tumor samples. Using Kaplan-Meier analysis no correlation of EpCAM overexpression was observed with conventional clinicopathologic features in this patient cohort. Taken together, these data suggest that EpCAM might become an attractive treatment target in a subgroup of patients with OSCC.

Effects of a suction laryngoscope in a model with simulated severe airway hemorrhage.

In severe airway hemorrhage, simultaneous suction and laryngoscopy may render intubation difficult. We built a suction laryngoscope that consists of an adjustable stainless steel-guide tube fixed at the lingual surface of a standard Macintosh laryngoscope blade. Via this steel-guide tube, a large suction catheter can be inserted and positioned exactly to suction pharyngeal blood or vomitus, rendering simultaneous suctioning and laryngoscopy possible. In contrast to previous suction laryngoscopes, our suction catheter has a large lumen, which enables fast suctioning and exact placement by adjusting the steel-guide tube. To assess whether our suction laryngoscope could provide better intubation conditions in comparison to a standard Macintosh laryngoscope in a bleeding airway scenario, 44 medical students intubated a manikin with severe simulated airway hemorrhage using our suction laryngoscope and a standard Macintosh laryngoscope in random order. There was no significant difference in time needed for intubation when using the suction versus the Macintosh laryngoscope (mean +/- SD: 43 +/- 13 vs 52 +/- 31 s; P = 0.07), but the number of esophageal intubations was significantly lower when using the suction laryngoscope [6 of 44 (13.6%) vs 19 of 44 (43.2%); P = 0.004]. In conclusion, when compared with a standard Macintosh laryngoscope, using a suction laryngoscope did not result in more rapid intubation, but significantly decreased the likelihood of esophageal intubations.

Traumatic intracranial haemorrhage in conscious patients with facial fractures--a review of 1959 cases.

OBJECTIVE: Facial fracture patients who are conscious with a Glasgow Coma Scale (GCS) score of 15 in the absence of clinical neurological abnormalities are commonly not expected to have suffered severe intracranial pathology. However, high velocity impact may result in intracranial haemorrhage in different compartments. METHODS: Over a 7-year period, 1959 facial fracture patients with GCS scores of 15 and the absence of neurological abnormalities were analysed. In 54 patients (2.8%) computed tomography scans revealed the presence of accompanying intracranial haemorrhage (study group). These patients were compared with the 1905 patients without intracranial haemorrhage (control group). RESULTS: Univariate analysis identified accompanying vomiting/nausea and seizures, cervical spine injuries, cranial vault and basal skull fractures to be significantly associated with intracranial bleeding. In multivariate analysis the risk was increased nearly 25-fold if an episode of vomiting/nausea had occurred. Seizures increased the risk of bleeding more than 15-fold. The mean functional outcome of the study group according to the Glasgow Outcome Scale was 4.7+/-0.7. CONCLUSION: Intracranial haemorrhage cannot be excluded in patients with facial fractures despite a GCS score of 15 and normal findings following neurological examination. Predictors, such as vomiting/nausea or seizures, skull fractures and closed head injuries, enhance the likelihood of an intracranial haemorrhage and have to be considered.

Changes of the Functional Capacity of Mesenchymal Stem Cells due to Aging or Age-Associated Disease - Implications for Clinical Applications and Donor Recruitment.

SUMMARY: In contrast to stem cells of embryonic origin, autologous tissue-specific stem cells are easier to introduce into the clinical practice. In this context, molecular and cellular changes, which alter tissue-specific stem cell properties with age, are of particular interest since elderly patients represent the main target group for cell-based therapies. The clinical use of mesenchymal stem cells is an emerging field, especially because this stem cell type appears to be amenable for the treatment of a large number of diseases, such as non-healing bone defects and fractures, inflammatory relief during arthritis, and the repair of suspensory ligament tears. More than that, mesenchymal stem cells provoke effective immune suppression in the context of graft-versus-host disease. Here, we present a comprehensive overview of the recent findings with special attention to age-related changes of mesenchymal stem cell properties and the consequential impact on tissue regeneration and repair, together with the current perception concerning their therapeutic application potential as well as the challenges associated with their clinical use.

A comparative in vivo study of strontium-functionalized and SLActive™ implant surfaces in early bone healing.

PURPOSE: Studies have shown that strontium-doped medical applications benefit bone metabolism leading to improved bone healing and osseointegration. Based on this knowledge, the aim of the study was to evaluate the performance of an implant surface, functionalized by a physical vapor deposition (PVD) coating (Ti-Sr-O), designed to yield predictable release of strontium. The Ti-Sr-O functionalized surface is compared to a routinely used, commercially available surface (SLActive™) with respect to bone-to-implant contact (BIC%) and new bone formation (BF%) in two defined regions of interest (ROI-I and ROI-II, respectively). MATERIALS AND METHODS: Ti-Sr-O functionalized, SLActive, and Grade 4 titanium implants were inserted in the femoral condyle of adult male New Zealand White rabbits. The PVD magnetron-sputtered Ti-Sr-O surface coating was characterized using scanning electron microscopy (SEM) for morphology and coating thickness. Strontium release and mechanical stability of the coating, under simulated insertion conditions, were evaluated. Furthermore, histomorphometrical BIC and BF were carried out 2 weeks after insertion. RESULTS: Histomorphometry revealed increased bone formation of Ti-Sr-O with significant differences compared to SLActive and Grade 4 titanium in both regions of interest, ROI-I and ROI-II, at 0-250 µm and 250-500 µm distance from the implant surfaces. Analogous results of bone-to-implant contact were observed for the two modified surfaces. CONCLUSION: The results show that a nanopatterned Ti-Sr-O functionalized titanium surface, with sustained release of strontium, increases peri-implant bone volume and could potentially contribute to enhancement of bone anchorage of osseointegrated implants.

Effect of strontium surface-functionalized implants on early and late osseointegration: A histological, spectrometric and tomographic evaluation.

Numerous in vivo, in vitro and clinical studies report on beneficial effects of strontium with respect to increased bone growth. Based on this knowledge the aim of this study was to evaluate early and late osseointegration stages of functionalized titanium implants showing sustained release of strontium (Sr) and further investigate its potential systemic effect. Strontium functionalized (Ti-Sr-O) and Grade 4 (Control) titanium implants were inserted in the femoral condyle of New Zealand White rabbits. The Ti-Sr-O coating was characterized using Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectrometry (EDX) for structure, coating thickness and chemical composition. Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES) was used to evaluate released strontium in vitro while Atomic Absorption Spectrometry (AAS) was utilized to monitor serum levels of strontium and calcium. Additionally, histological and tomographic analysis of bone-to-implant contact (BIC%) and bone formation (BF%) was performed, following implantation periods of two or twelve weeks, respectively. Median values for BIC% for Ti-Sr-O revealed significant differences within the two- and twelve-week observation periods, while exceeding BF% was discovered especially after twelve weeks when performing the histological evaluation. The results from the micro-computed tomography (µ-CT) showed no significant differences, when comparing the experimental groups. AAS measurements did not indicate a systemic effect by the local strontium release. Within the limitations of the study, it was shown that a Ti-Sr-O coating with sustained release characteristics of strontium, accelerates bone apposition and represents a potential potent surface modification for endosseous medical implant devices. STATEMENT OF SIGNIFICANCE: This study presents first data with respect to early and late in vivo response on a strontium functionalized titanium surface comprising a nanotopography manufactured by a magnetron sputtering process. We investigated different osseointegration stages of screw-shaped implants with dental implant geometries in a rabbit femur model observing beneficial effects of the functionalized surface on bone-to-implant contact and bone formation caused by tailored release of the bone anabolic strontium. Histomorphometrical data revealed that a functionalized titanium surface with controlled liberation of strontium accelerates osseointegration while spectrometry measurements did not indicate a potential systemic effect of this osteoinductive agent and could thus have impact on modifications of medical implant devices.

Comparing the effect of strontium-functionalized and fluoride-modified surfaces on early osseointegration.

BACKGROUND: Studies have shown that medical devices comprising strontium contribute to bone healing and osseointegration. The aim of this study was to evaluate the in vivo performance of surface-functionalized implants (Ti-Sr-O) showing predictable release characteristics of strontium and compare it to performance a commercially available fluoride-modified surface. METHODS: Ti-Sr-O functionalized, fluoride-modified,  Grade 4 titanium implants were inserted in the femoral condyle of adult male New Zealand white rabbits. Atomic absorption spectrometry (AAS) was utilized to monitor strontium blood serum levels. Two weeks after insertion, histomorphometric evaluation was performed with respect to bone-to-implant contact (BIC%) and bone formation (BF%) using defined regions of interest. RESULTS: Mean values for BIC% showed a comparable degree of osseointegration for Ti-Sr-O and the fluoride-modified surface, while BF% revealed a significant difference in increased BF with Ti-Sr-O. AAS measurements did not indicate any influence of the Ti-Sr-O modified implants on the strontium blood serum concentrations. CONCLUSIONS: Within the limitations of this study, it was shown that the Ti-Sr-O coating, with sustained release characteristics of strontium, enhanced bone apposition and, thus, could find practical applications, e.g., within the field of medical implantology.

Nanocrystalline diamond--an excellent platform for life science applications.

Nanocrystalline diamond (NCD) has recently been successfully utilized in a variety of life science applications. NCD films are favorable and salubrious substrates for cells during cultivation. Therefore NCD has also been employed in tissue engineering strategies. NCD as reported in this contribution was grown by means of a modified hot-filament chemical vapor deposition technique, which results in less than 3% sp2-hybridization and yields grain sizes of 5-20 nm. After production the NCD surface was rather hydrophobic, however it could be efficiently refined to exhibit more hydrophilic properties. Changing of the surface structure was found to be an efficient means to influence growth and differentiation capacity of a variety of cells. The particular needs for any given cell type has to be proven empirically. Yet flexible features of NCD appear to be superior to plastic surfaces which can be hardly changed in quality. Besides its molecular properties, crystal structural peculiarities of NCD appear to influence cell growth as well. In our attempt to facilitate, highly specialized applications in biomedicine, we recently discovered that growth factors can be tightly bound to NCD by mere physisorption. Hence, combination of surface functionalization together with further options to coat NCD with any kind of three-dimensional structure opens up new avenues for many more applications. In fact, high through-put protein profiling of early disease stages may become possible from serum samples, because proteins bound to NCD can now be efficiently analyzed by MALDI/TOF-MS. Given these results, it is to be presumed that the physical properties and effective electrochemical characteristics of NCD will allow tailoring devices suitable for many more diagnostic as well as therapeutic applications.