Metallic Prostheses Research Articles

Experimental Analysis of Stress Shielding Effects in Screw Spacers Placed in Porcine Spinal Tissue.

Bone cortical tissues reorganize and remodel in response to tensile forces acting on them, while compressive forces cause atrophy. However, implants support most of the payload. Bones do not regenerate, and stress shielding occurs. The aim is to analyze the biomechanical behavior of a lumbar cage to study the implant's stress shielding. The ASTM E-9 standard was used with the necessary adjustments to perform compression tests on lumbar and thoracic porcine spinal vertebrae. Twelve cases were analyzed: six with the metal prosthesis and six with the PEEK implant. A mathematical model based on the Hertz contact theory is proposed to assess the stress shielding for endoprosthesis used in spine pathologies. The lumbar spacer (screw) helps to reduce the stress shielding effect due to the ACME thread. The best interspinous spacer is the PEEK screw. It does not embed in bone. The deformation capability increases by 11.5% and supports 78.6 kg more than a system without any interspinous spacer.

The effects of physiologically relevant environmental conditions on the mechanical properties of 3D-printed biopolymer nanocomposites

The demand for synthetic bone graft biomaterials has grown in recent years to alleviate the dependence on natural bone grafts and metal prostheses which are associated with significant practical and clinical issues. Biopolymer nanocomposites are a class of materials that display strong potential for these synthetic materials, especially when processed using additive manufacturing technologies. Novel nanocomposite biomaterials capable of masked stereolithography printing have been developed from functionalized plant-based monomers and hydroxyapatite (HA) with mechanical properties exceeding those of commercial bone cements. However, these biomaterials have not been evaluated under relevant physiological conditions. The effects of temperature (room temperature vs. 37 °C) and water absorption on the physical, surface, and mechanical properties of HA-containing biopolymer nanocomposites were investigated. Exposure to relevant conditions led to substantial impacts on material performance, such as significantly reduced mechanical strength and stiffness. For instance, a composite containing 10 vol% HA and functionalized monomers had 26 and 21% reductions in compressive yield strength and elastic modulus, respectively. After 14 days incubation in phosphate buffered saline, the same composition displayed a 62% decrease in compressive yield strength to 28 MPa. This manuscript demonstrates the relevance and importance of evaluating biomaterials under appropriate physiological conditions throughout their development and provides direction for future material development of HA-containing biopolymer nanocomposites.

Temporomandibular joint alloplastic replacement failure

Temporomandibular joint disorders are common, with alloplastic temporomandibular joint replacement (TMJR) being one method of addressing chronic pain and movement limitations that cannot otherwise be managed. Despite this, TMJR has known complications that can lead to failure. We present our experience of managing these cases and review the current evidence on the management and outcomes of alloplastic TMJR failures. Until 2015 our unit regularly used Dundee full metal prostheses, and encountered multiple issues such as infection, heterotopic bone formation, and progression of osteoarthritis beneath the condylar element. We also present our experience with other standard TMJR implants. One common cause of failure we observed is improper placement of a prosthesis due to poor technique, for instance, placement of the fossa implant too close to the ear canal can cause unresolved postoperative pain. There is no consensus on the management of TMJR, but non-surgical measures are preferred initially and surgical intervention is reserved for later stages. Recently our unit has managed numerous failure cases, employing a multidisciplinary approach combined with thorough preoperative planning and postoperative care, which has proven effective in reducing complications and improving outcomes. Based on our experience, we do not recommend the use of Dundee full metal prostheses for TMJR. Appropriate training in the placement of contemporary implants remains crucial. Suboptimal alignment of the implant in some cases does not need surgical intervention, but surgical management is justifiable in cases of persistent symptoms and functional limitations. When placing stock implants or designing a custom-made implant for an adult, we recommend that the posterior edge of the fossa component is at least 3 mm away from the bone of the ear canal.

Cellulose Acetate and Polycaprolactone Fibre Coatings on Medical-Grade Metal Substrates for Controlled Drug Release.

This study explores a method that has the potential to be cost effective in inhibiting biofilm formation on metallic prostheses, thereby preventing rejection or the requirement for replacement. A cost-effective metal alloy used in biomedical implants was chosen as the substrate, and ibuprofen (Ibu), a well-known anti-inflammatory drug, was selected for drug release tests for its widespread availability and accessibility. Multilayer coatings consisting of cellulose acetate (CA), polycaprolactone (PCL), and chitosan (CHI), with or without ibuprofen (Ibu) content, were applied onto medical-grade stainless steel (SS-316 type) through electrospinning, electrospray, or blow spinning. The adhesion of the CA, PCL, and layered CA/PCL membranes, with thicknesses ranging from 20 to 100 μm, to SS substrates varied between 0.15 N and 0.22 N without CHI, which increased to 0.21 and 0.74 N, respectively, when a CHI interlayer was introduced by electrospraying between the SS and the coatings. Although drug release in a simulated body fluid (SBF) medium is predominantly governed by diffusion-driven mechanisms in all single- and multilayer coatings, a delayed release was noted in CA coatings containing Ibu when overlaid with a PCL coating produced by blow spinning. This suggests avenues for further investigations into combinations of multilayer coatings, both with and without drug-imbued layers.

Comparison of Maintenance in Different Materials for Implant Dental Prostheses

ABSTRACT Context: In contemporary prosthodontics, implant-supported dental prostheses are frequently utilized to restore function and esthetics for individuals who are edentulous. The prosthetic material selection has a big impact on long-term performance and maintenance needs. Methods: A retrospective review of patient files from the dental implant clinic of a tertiary care facility was done. Included were patients who had dental prosthesis supported by implants between January 2018 and December 2022. Data were gathered and examined on the prosthesis material, follow-up visits, and maintenance interventions (adjustments, repairs, and replacements). Results: Materials for 50 prostheses made of porcelain, 45 prostheses made of acrylic, 35 prostheses made of metal, and 40 prostheses made of composite were assessed. When it came to modifications and repairs, porcelain prosthesis needed less work than acrylic prostheses. Composite prostheses required the least amount of maintenance overall, whereas metal prostheses indicated a considerable demand for maintenance. Conclusion: Superior durability is provided by porcelain, frequent repairs are needed for acrylic, structural strength is provided by metal, and composite material gives promising esthetics with low maintenance requirements. These results highlight how crucial it is to take material properties into account when choosing a prosthesis to maximize long-term results and patient happiness.

Model-based Roentgen Stereophotogrammetric Analysis (RSA) of polyethylene implants

Model-based Roentgen Stereophotogrammetric Analysis (RSA) is able to measure the migration of metallic prostheses with submillimeter accuracy through contour-detection and 3D surface model matching techniques. However, contour-detection is only possible if the prosthesis is clearly visible in the radiograph; consequently Model-based RSA cannot be directly used for polymeric materials due to their limited X-ray attenuation; this is especially clinically relevant for all-polyethylene implants. In this study the radiopacity of unicompartmental Ultra-High Molecular Weight Polyethylene (UHMWPE) knee bearings was increased by diffusing an oil-based contrast agent into the surface to create three different levels of surface radiopacity. Model-based RSA was performed on the bearings alone, the bearings alongside a metallic component held in position using a phantom, the bearings cemented into a Sawbone tibia, and the bearings at different distances from the femoral component. For each condition the precision and accuracy of zero motion of Model-based RSA were assessed. The radiopaque bearings could be located in the stereo-radiographs using Model-based RSA an accuracy comparable to metallic parts for translational movements (0.03 mm to 0.50 mm). For rotational movements, the accuracy was lower (0.1∘ to 3.0∘). The measurement accuracy was compared for all the radiopacity levels and no significant difference was found (p=0.08). This study demonstrates that contrast enhanced radiopaque polyethylene can be used for Model-based RSA studies and has equivalent translational measurement precision to metallic parts in the superior-inferior direction.

Role of Polyetheretherketone in Prosthodontics: A Literature Review.

Implant prostheses and other fixed and removable metal prostheses have led to an increase in demand for the development of new and efficient materials such as high-performance polymers polyetheretherketone (PEEK) over titanium and other metals because of their further complications in the human body. PEEK is a polymer that is nontoxic and has a modulus of elasticity that is comparable to that of human bone. PEEK implants provide benefits over metal implants, such as reducing the stress shielding effect, simple processing, and color resemblance to natural teeth. And it is a fantastic alternative to titanium for dental and orthopedic implants. The current review is undertaken to understand the properties of this PEEK material to weigh its benefits and drawbacks for potential use in dental implants and other prostheses.

Intensity-modulated radiotherapy quality assurance by alanine-EPR and gel dosimetry of a simulated prostate treatment with bilateral metallic prostheses

The presence of metallic prostheses in patients undergoing prostate radiotherapy treatment can lead to scattered doses, compromising treatment reproducibility. This study aims to assess doses in the Planning Target Volume (PTV) and surrounding areas using a water phantom containing pelvic bones and bilateral metallic prostheses. Intensity Modulated Radiotherapy (IMRT) with optimization tools avoiding input dose to the prosthesis was employed. Experimental verification utilized a modified Fricke xylenol orange gel dosimeter (FXO-f) in a 63 mm diameter, 100 mm height cylinder (310 ml volume) for PTV dose checks, and alanine dosimeters for assessing doses in the PTV vicinity and near metallic prostheses. Evaluating doses near prostheses is vital as post-radiotherapy prosthesis loosening has been speculated, possibly linked to overexposure. Gamma evaluation with FXO-f dosimeter yielded approved gamma indices in 97.7% of data points versus TPS, indicating good agreement with linear accelerator-reproduced results. Alanine dosimeter results ranged between (1.0 ± 0.3), (1.2 ± 0.3) Gy, (1.4 ± 0.3) Gy, and (2.0 ± 0.3) Gy, which are comparable to TPS-calculated doses within the dosimeter volume. This result indicates that the heterogeneity correction applied by the Analytical Anisotropic Algorithm used for dose calculation and the avoidance tool employed in the treatment planning could addressed the problem. In summary, this study demonstrates that the treatment technique entering fields towards prostheses, with optimization tools to produce the desirable results.

Revision rate in metal compared to ceramic humeral head total shoulder arthroplasty and hemiarthroplasty.

Metal and ceramic humeral head bearing surfaces are available choices in anatomical shoulder arthroplasties. Wear studies have shown superior performance of ceramic heads, however comparison of clinical outcomes according to bearing surface in total shoulder arthroplasty (TSA) and hemiarthroplasty (HA) is limited. This study aimed to compare the rates of revision and reoperation following metal and ceramic humeral head TSA and HA using data from the National Joint Registry (NJR), which collects data from England, Wales, Northern Ireland, Isle of Man and the States of Guernsey. NJR shoulder arthroplasty records were linked to Hospital Episode Statistics and the National Mortality Register. TSA and HA performed for osteoarthritis (OA) in patients with an intact rotator cuff were included. Metal and ceramic humeral head prostheses were matched within separate TSA and HA groups using propensity scores based on 12 and 11 characteristics, respectively. The primary outcome was time to first revision and the secondary outcome was non-revision reoperation. A total of 4,799 TSAs (3,578 metal, 1,221 ceramic) and 1,363 HAs (1,020 metal, 343 ceramic) were included. The rate of revision was higher for metal compared with ceramic TSA, hazard ratio (HR) 3.31 (95% confidence interval (CI) 1.67 to 6.58). At eight years, prosthesis survival for ceramic TSA was 98.7% (95% CI 97.3 to 99.4) compared with 96.4% (95% CI 95.2 to 97.3) for metal TSA. The majority of revision TSAs were for cuff insufficiency or instability/dislocation. There was no significant difference in the revision rate for ceramic compared with metal head HA (HR 1.33 (95% CI 0.76 to 2.34)). For ceramic HA, eight-year prosthetic survival was 92.8% (95% CI 86.9 to 96.1), compared with 91.6% (95% CI 89.3 to 93.5) for metal HA. The majority of revision HAs were for cuff failure. The rate of all-cause revision was higher following metal compared with ceramic humeral head TSA in patients with OA and an intact rotator cuff. There was no difference in the revision rate for HA according to bearing surface.

Heating of metallic orthodontic devices during anti-aging treatment with vacuum and electromagnetic fields: In vitro study.

The physical appearance of an individual plays a primary role as it influences the opinion of the viewer. For this reason, orthodontic therapy to improve perceived aesthetics is in high demand among patients. This factor, combined with the increase in the number of non-invasive facial aesthetic treatments, has led to the need to understand potential risk factors in the application of medical devices to the perioral skin in patients with fixed orthodontic appliances. The aim of this study was to evaluate in vitro heating of the orthodontic bracket following electromagnetic fields and negative pressure (V-EMF) used as an anti-aging treatment. Two different types of titanium alloy wires, one made of "beta-Titanium" alloy and the other "Ni-Ti" (DW Lingual Systems GmbH-Bad Essen-Germany) were used. The orthodontic wires and brackets mounted on a resin mouth were covered with porcine muscle tissue, then subjected to anti-aging therapy with a Bi-one LifeTouchTherapy medical device (Expo Italia Srl-Florence-Italy) which generates a combination of vacuum and electromagnetic fields (V-EMF) already adopted for antiaging therapy. During administration of the therapy, the orthodontic brackets and porcine tissue were thermally monitored using a Wavetek Materman TMD90 thermal probe (Willtek Communications GmbH-Germany). In total 20 orthodontic mouths were used, 10 with Beta Titanium wires and 10 with Nickel Titanium wires. A temperature increase of about 1°C was recorded in each group. The outcome of the present research shows that the absolute temperatures measured on orthodontic appliances, which, despite having a slightly different curve, both show an increase in temperature of 1.1°C at the end of the session, thus falling well within the safety range of 2°C as specified by the standard CENELEC EN 45502-1. Therefore, V-EMF therapy can be considered safe for the entire dental system and for metal prostheses, which tend to heat up at most as much as biological tissue (+0.9°C/1.1°C vs. 1.1°C/1.1°C). In conclusion, anti-aging therapy with V-EMF causes a thermal increase on orthodontic brackets that is not harmful to pulp health.

PEEK-Polymer for Dental Implants: A Concise Review

The biomaterials applicable in dental implantology, or implantology generally, are subject to specific requirements, namely biocompatibility, osseointegration, resistance to fracture/ oxidative degradation/ long-term compressive stress/ hydrolisis in boiling water, suitable morphology, suitable physical properties (including mechanical properties), aesthetics, etc. When selecting a suitable material for dental implants, it is also necessary to consider the patient s current health condition and possible complications when placing titanium implants and alloys. If there is a risk of an allergic reaction or hypersensitivity to any of the components of the metal prosthesis, the placement of a semi-crystalline thermoplastic implant - called polyetheretherketone, abbreviated PEEK - is a possible option. Such a wide range of stiffness means that PEEK formulations can be produced with modulus values similar to cortical bone. PEEK is classified as a High Performance Polymer of polymer pyramide (such as Polysulfones polybutylene terephthalate). PEEK can be applied for dental abutment and dental body. This article summarises basic information on the structure and properties of PEEK polymer, advantages/ disadvantages (compared to metal - titanium restorations), application and general information from the examined field.

Soft and Hard Tissue Integration around Percutaneous Bone-Anchored Titanium Prostheses: Toward Achieving Holistic Biointegration.

A holistic biointegration of percutaneous bone-anchored metallic prostheses with both hard and soft tissues dictates their longevity in the human body. While titanium (Ti) has nearly solved osseointegration, soft tissue integration of percutaneous metallic prostheses is a perennial problem. Unlike the firm soft tissue sealing in biological percutaneous structures (fingernails and teeth), foreign body response of the skin to titanium (Ti) leads to inflammation, epidermal downgrowth and inferior peri-implant soft tissue sealing. This review discusses various implant surface treatments/texturing and coatings for osseointegration, soft tissue integration, and against bacterial attachment. While surface microroughness by SLA (sandblasting with large grit and acid etched) and porous calcium phosphate (CaP) coatings improve Ti osseointegration, smooth and textured titania nanopores, nanotubes, microgrooves, and biomolecular coatings encourage soft tissue attachment. However, the inferior peri-implant soft tissue sealing compared to natural teeth can lead to peri-implantitis. Toward this end, the application of smart multifunctional bioadhesives with strong adhesion to soft tissues, mechanical resilience, durability, antibacterial, and immunomodulatory properties for soft tissue attachment to metallic prostheses is proposed.

Diagnostic value and clinical significance of high-resolution ultrasonography compared to magnetic resonance imaging in diagnosing temporomandibular joint dislocation: a systematic review

BACKGROUND Temporomandibular joint (TMJ) dislocation is uncommon, yet it is associated with a significant negative effect on the patient’s quality of life. Magnetic resonance imaging (MRI), a gold standard for diagnosing TMJ dislocation, is expensive, time-consuming, and cannot be performed on patients with pacemakers and metallic prostheses. On the other hand, high-resolution ultrasonography (HRUS) has low cost, high accessibility, and is less time-consuming. This study aimed to compare the accuracy and reliability of HRUS to MRI in diagnosing TMJ dislocation. METHODS A comprehensive literature search was conducted using PubMed, Cochrane Library, ScienceDirect, and EBSCOhost databases. Keywords such as temporomandibular joint dislocation, temporomandibular displacement, MRI, and ultrasonography were utilized for the search. The articles obtained were then selected based on the inclusion and exclusion criteria, and the quality assessment was conducted using the QUADAS-2 tool. RESULTS 5 studies were included in this systematic review. The critical appraisal results showed sensitivity ranging from 74.3–93.7%, specificity from 84.2–100%, positive predictive value from 68.2–100%, negative predictive value from 64.0–98.3%, and accuracy from 77.7–91.7% of HRUS compared to MRI. CONCLUSIONS HRUS is a reliable method for diagnosing TMJ dislocation. However, MRI is still necessary in selected and more advanced cases.

Porous versus solid shoulder implants in humeri of different bone densities: A finite element analysis.

Porous metallic prosthesis components can now be manufactured using additive manufacturing techniques, and may prove beneficial for promoting bony ingrowth, for accommodating drug delivery systems, and for reducing stress shielding. Using finite element modeling techniques, 36 scenarios (three porous stems, three bone densities, and four held arm positions) were analysed to assess the viability of porous humeral stems for use in total shoulder arthroplasty, and their resulting mechanobiological impact on the surrounding humerus bone. All three porous stems were predicted to experience stresses below the yield strength of Ti6Al4V (880 MPa) and to be capable of withstanding more than 10 million cycles of each loading scenario before failure. There was an indication that within an 80 mm region of the proximal humerus, there would be a reduction in bone resorption as stem porosity increased. Overall, this study shows promise that these porous structures are mechanically viable for incorporation into permanent shoulder prostheses to combat orthopedic infections.

Modular intercalary prosthetic reconstruction for malignant and metastatic tumours of the proximal femur

To illustrate the surgical technique and explore clinical outcomes of the reconstruction for the malignant and metastatic bone tumour of proximal femur with metallic modular intercalary prosthesis. Sixteen patients who underwent modular intercalary prosthetic reconstruction after tumour resection were included from April 2012 and October 2020. Prosthesis and screws parameters, resected bone length and residual bone length, clinical outcomes and survivorship were analyzed. All patients were followed up for an average of 19 months (range 1–74). In our series, 12 patients died of the progression of the primary disease at the final follow-up. The cumulative survivorship since the treatment of proximal femoral metastasis was 78.6% (11 patients) at 6 months and 38.5% (5 patients) at 1 year. The mean MSTS score was 22.25 ± 4.55 among all patients. There were no cases of loosening or breakage of the prostheses, plates or screws, despite the various measurements of prostheses and residual bones. Modular intercalary prosthetic reconstruction was an effective method for malignant tumour of the proximal femur, including the advantages of providing early pain relief, quickly restoring postoperative function, required a short operation time, and preserving the adjacent joints.

Improvement of metal artifact reduction in dental CBCT using a CdTe photon-counting detector: Simulation study

In dental cone-beam computed tomography (CBCT), the image quality often degrades when patients have metallic objects such as metal implants and/or metal prostheses. Metal artifacts typically appear as streaks and shadows in the reconstructed CT images, limiting their clinical usefulness. Although various metal artifact reduction (MAR) methods are used in dental CBCT, no algorithm that can robustly remove metal artifacts has been universally accepted. Recent research has explored the potential benefits of using of a photon-counting detector (PCD) to advance enhanced MAR. PCD can classify x-ray photons into several different energy bins, allowing for more precise measurements of x-ray attenuation. Therefore, in this study, we propose a new MAR method based on the use of a PCD, named the high-energy trace normalized-MAR (HT-NMAR) algorithm, to ensure improved image quality. The proposed MAR algorithm consists of three main steps: 1) Segmentation of the metal trace using a high-energy binned sinogram, 2) Generation of a residual artifact-reduced prior, 3) Sinogram completion with the segmented metal trace and the prior, followed by CBCT reconstruction. We conducted a simulation on a numerical head phantom with metal inserts using a PCD simulation toolkit to demonstrate its efficacy. Our simulation study indicates that the proposed MAR method considerably reduces metal artifacts in CBCT and shows a better image performance than other existing MAR methods in reducing streak artifacts without any contrast anomaly.

Geometric distortion caused by metallic femoral head prosthesis in prostate cancer imaging on an MR Linac: in-vivo measurements of spatial deformation.

Metallic implants cause artefacts and distortion on MRI. To ensure accurate dose delivery and plan adaptation on an MR Linac, there is a need to evaluate distortion caused. Participants were imaged on an MR Linac (Elekta Unity, Elekta AB Stockholm). Three sequences were evaluated. Two vendor supplied (T2W TSE 3D), and one T2W TSE 3D optimized to reduce metal artefact distortions. Images were rigidly registered to CT images by a single observer, using bony anatomy. Three coronal and three axial images were selected, and six paired, adjacent, bony landmarks were identified on each slice. Images bisecting treatment isocentre were included. Difference between landmark coordinates was taken to be measure of distortion. Five observers participated. Thirty six pairs of bony landmarks were identified. Median difference in position of landmarks was ≤3 mm (range 0.3-4.4 mm). One-way analysis of variance (ANOVA) between observer means showed no significant variation between sequences or patients (P = 1.26 in plane, P = 0.11 through plane). Interobserver intra class correlation (ICC) was 0.70 in-plane and 0.78 through-plane. Intra-observer ICC for three observers was 0.76, 0.81, 0.83, showing moderate to good reliability on this small cohort. This in-vivo feasibility study suggests distortion due to metallic hip prosthesis is not an obstacle for pelvic radiotherapy on an MR Linac. Research on the impact on plan quality is warranted. This work supports feasibility of treating patients with metallic hip prosthesis on an MR Linac.

Impact of fixed dental prosthesis on neuroimaging: assessment of artefacts.

To determine the frequency and extent of artefacts in magnetic resonance imaging and/or computed tomography scans of head caused by fixed dental prosthesis. The retrospective study was conducted at Aga Khan University Hospital from July to December 2021, and comprised magnetic resonance imaging and/or computed tomography scans from January 2015 to December 2020 of the head of individuals with existing fixed dental prosthetic work at the time of exposure. They were analysed for the presence of artefacts. The association between artefacts and the presence of fixed dental prosthesis was explored. Data was analysed using SPSS 23. Of the 297 images evaluated, 173 (58%) were magnetic resonance imaging scans, and 124(42%) were computed tomography scans. The most common artefacts was grade I 148(49.8%), followed by grade II 140(47.1%) and grade III 9(3%). There was no significant association between fixed dental prosthesis and the artefacts (p>0.05). There should be no reservations in placing fixed metal prosthesis in individuals on account of future brain scans.

CALCIUM PHOSPHATE-BASED NANOCOATING IN ORTHOPAEDICS: INFLUENCE OF COMPOSITION AND SUBSTRATE HEATING ON FILM PROPERTIES AND BM-MSC BEHAVIOUR

Calcium phosphates-based (CaPs) nanocoatings on metallic prosthesis are widely studied in orthopedics and dentistry because they mimic the mineral component of native human bone and favor the osseointegration process. Despite the fact that different calcium phosphates have different properties (composition, crystallinity, and ion release), only stoichiometric hydroxyapatite (HA) films have been analyzed in deep. Here, we have realized films of different CaPs (HA, beta-tricalcium phosphate (β-TCP) and brushite (DCPD)) onto Ti6Al4V microrough substrates by Ionized Jet Deposition (IJD). We have implemented the heating of substrates at 400°C during deposition to see the effect on coating properties.Different film features are evaluated: morphology and topography (FEG-SEM, AFM), physical-chemical composition (FT-IR and EDS), dissolution profile and adhesion to substrate (scratch test), with a focus on how the different CaPs and temperature changed the coating features. After coating optimization, we have studied the in vitro BM-MSC behavior, in term of viability and early adhesion.We have obtained good transfer of fidelity in composition from target to coating for all CaPs, with nanostructured films formed by globular aggregates (~300 nm diameter), with homogeneous and uniform coverage of the substrate surface, without cracks. The heating during deposition has increased the adhesion of the films to the substrate, with higher stability in medium immersion and wettability, features that can improve the biological behavior of cells. All CaP coatings have showed excellent biocompatibility, with DCPD coating that promote higher cells viability at 14 days respect to HA and β- TCP films. About the early cell adhesion, the BM-MSC have showed switch from a globular to an elongated morphology at 6 hours in all coatings respect to the uncoated titanium, sign of better adhesion.From these results, the fabrication of different CaP nanocoatings with IJD can be a promising for applications in orthopedics and dentistry.

Fibronectin Conformations after Electrodeposition onto 316L Stainless Steel Substrates Enhanced Early-Stage Osteoblasts' Adhesion but Affected Their Behavior.

The implantation of metallic orthopedic prostheses is increasingly common due to an aging population and accidents. There is a real societal need to implement new metal implants that combine durability, good mechanical properties, excellent biocompatibility, as well as affordable costs. Since the functionalization of low-cost 316L stainless steel substrates through the successive electrodeposition of a polypyrrole film (PPy) and a calcium phosphate deposit doped with silicon was previously carried out by our labs, we have also developed a bio-functional coating by electrodepositing or oxidating of fibronectin (Fn) coating. Fn is an extracellular matrix glycoprotein involved in cell adhesion and differentiation. Impacts of either electrodeposition or oxidation on the structure and functionality of Fn were first studied. Thus, electrodeposition is the technique that permits the highest deposition of fibronectin, compared to adsorption or oxidation. Furthermore, electrodeposition seems to strongly modify Fn conformation by the formation of intermingled long fibers, resulting in changes to the accessibility of the molecular probes tested (antibodies directed against Fn whole molecule and Fn cell-binding domain). Then, the effects of either electrodeposited Fn or oxidized Fn were validated by the resulting pre-osteoblast behavior. Electrodeposition reduced pre-osteoblasts' ability to remodel Fn coating on supports because of a partial modification of Fn conformation, which reduced accessibility to the cell-binding domain. Electrodeposited Fn also diminished α5 integrin secretion and clustering along the plasma membrane. However, the N-terminal extremity of Fn was not modified by electrodeposition as demonstrated by Staphylococcus aureus attachment after 3 h of culture on a specific domain localized in this region. Moreover, the number of pre-osteoblasts remains stable after 3 h culture on either adsorbed, oxidized, or electrodeposited Fn deposits. In contrast, mitochondrial activity and cell proliferation were significantly higher on adsorbed Fn compared with electrodeposited Fn after 48 h culture. Hence, electro-deposited Fn seems more favorable to pre-osteoblast early-stage behavior than during a longer culture of 24 h and 48 h. The electrodeposition of matrix proteins could be improved to maintain their bio-activity and to develop this promising, fast technique to bio-functionalize metallic implants.