Electro-Assisted Deposition of Calcium Phosphate on Self-Assembled Monolayers

Assessment of a novel electrochemically deposited smart bioactive trabecular coating (SBTC®): a randomized controlled clinical trial

OBJECTIVES

A randomized controlled clinical trial of dental implants was conducted to compare the clinical properties of a novel electrochemically deposited calcium phosphate coating to those of a common marketed surface treatment.

MATERIAL AND METHODS

Forty implants of the same brand and type were placed in 20 fully edentulous participants requiring mandibular implantation. The two study groups were defined by the surface treatment of the implants. 20 implants in the control group were coated via a commercial electrochemical surface treatment that forms a mixture of brushite and hydroxyapatite, while the remaining 20 in the test group were coated with a novel electrochemical Smart Bioactive Trabecular Coating (SBTC®). A split-mouth design was employed, with each participants receiving one control implant in one mandibular side and a test implant in the other. To mitigate potential operator-handedness bias, control and test implants were randomly assigned to mandibular sides. All cases underwent digital planning, implant placement with a static surgical guide, and participants received locator-anchored full-arch dentures. The primary outcome was implant stability (measured using Osstell ISQ) assessed at insertion, loading, and then 3 months, 9 months, and 2 years post-insertion. The secondary outcome was bone level change (in millimeters) over the 2-year observation period. Oral health-related quality of life (OHRQL) was monitored using the OHIP-14 questionnaire. Complications and adverse events were recorded.

RESULTS

Successful osseointegration and implant stability were achieved in all cases, allowing loading. ISQ values steadily increased throughout the observation period. While no significant differences were observed between the SBTC® and control coatings, the test group exhibited a higher ISQ gain. Bone resorption was somewhat lower in the SBTC® but not significantly so. Patients' OHRQL significantly improved after denture delivery and remained stable throughout the follow-up. No complications or adverse events were observed.

CONCLUSIONS

Based on the study results, we conclude that the new surface treatment is a safe alternative to the widely used control surface, demonstrating similar osseointegrative properties and time-dependent bone level changes. Further research may explore the broader implications of these findings.

TRIAL REGISTRATION

The study is registered on clinicaltrials.gov under the identifier ID: NCT06034171.

Deactivation of cyanobacteria blooms and simultaneous recovery phosphorus through electrolysis method

A novel method for remediating eutrophic lakes through electrolysis was made possible by one titanium (Ti) mesh, which serves as a cathode and two anodes of Ti mesh coated with ruthenium (IV) oxide and iridium (IV) oxide (RuO₂-IrO₂/Ti). Once the three-electrode components RuO₂-IrO₂/Ti and Ti are stabilized, they can carry out electrolytic reaction to control cyanobacteria blooms and assist with the remediation of eutrophic water. The order of influence on the theoretical energy consumption involved in removing algae is as follows: The electrode spacing was more effective than electrode voltage, which proved more effective than electrolysis time through the orthogonal test method. Thus, an electrode spacing of 60 mm, an electrode voltage of 30 V, and an electrolysis time of 12 h are the optimal electrolysis methods used to remove cyanobacterial blooms. The strong acidic environment produced by the anode increased the concentration of hydroxyl radical (•OH) and other strong oxidizing substances, which were the main roles that made cyanobacteria bloom inactivation. The electrolysis reaction was conducive to the transformation of organophosphorus in cyanobacterial blooms to dissolved inorganic phosphorus (DIP) in water. Some DIP was most deposited on the cathode after electro-depositing enhanced the removal of P in water with the 12-h prolonged electrolysis time. Meanwhile, it was beneficial to reduce the total nitrogen (TN) and ammonia nitrogen (NH₃-N) in the water. Thus, electrolysis proved to be an effective way to the inactivation of cyanobacteria blooms and simultaneously recover P as the concentration became higher.

Electrochemically Enhanced Deposition of Scale from Chosen Formation Waters from the Norwegian Continental Shelf

Reservoir formation waters typically contain scaling ions which can precipitate and form mineral deposits. Such mineral deposition can be accelerated electrochemically, whereby the application of potential between two electrodes results in oxygen reduction and water electrolysis. Both processes change the local pH near the electrodes and affect the surface deposition of pH-sensitive minerals. In the context of the plugging and abandonment of wells, electrochemically enhanced deposition could offer a cost-effective alternative to the established methods that rely on setting cement plugs. In this paper, we tested the scale electro-deposition ability of six different formation waters from selected reservoirs along the Norwegian continental shelf using two experimental setups, one containing CO2 and one without CO2. As the electrochemical deposition of scaling minerals relies on local pH changes near the cathode, geochemical modelling was performed to predict oversaturation with respect to the different mineral phases at different pH values. In a CO2-free environment, the formation waters are mainly oversaturated with portlandite at pH > 12. When CO2 was introduced to the system, the formation waters were oversaturated with calcite. The presence of mineral phases was confirmed by powder X-ray diffraction (XRD) analyses of the mineral deposits obtained in the laboratory experiments. The geochemical-modelling results indicate several oversaturated Mg-bearing minerals (e.g., brucite, dolomite, aragonite) in the formation waters but these, according to XRD results, were absent in the deposits, which is likely due to the significant domination of calcium-scaling ions in the solution. The amount of deposit was found to be proportional to the concentration of calcium present in the formation waters. Formation waters with a high concentration of Ca ions and a high conductivity yielded more precipitate.

Electrochemical Studies on CaP Electrodeposition on Three Dimensional Surfaces of Selective Laser Melted Titanium Scaffold

In this work, calcium phosphate (CaP) coating was electrodeposited on the three dimensional surface of SLM-Ti scaffolds. The in situ measurement showed that the potential variation within 5 mm thickness porous selective laser melting (SLM)-Ti samples was about 80 mV as a result of the low conductivity of CaP coatings. SEM observation results revealed that the coating morphology depended on the distance between the surface position of porous SLM-Ti electrode and the auxiliary electrode. Based on the compared electrochemical experiments, it was found that the top and the bottom surfaces of SLM-Ti scaffolds exhibited continuous nucleation and instantaneous nucleation behavior respectively. The Electrochemical impedance spectroscopy (EIS) results also revealed that the electrodeposition processes at different depth of SLM-Ti scaffolds were not synchronized. These differences were ultimately caused by the non-uniform distribution of the potential and the current inside porous SLM-Ti electrodes. The present work provides a basic research method for studying the mechanism of the electrochemical process on three dimensional surfaces of SLM-Ti scaffolds.

Corrosion of Metallic Biomaterials: A Review

Metallic biomaterials are used in medical devices in humans more than any other family of materials. The corrosion resistance of an implant material affects its functionality and durability and is a prime factor governing biocompatibility. The fundamental paradigm of metallic biomaterials, except biodegradable metals, has been "the more corrosion resistant, the more biocompatible." The body environment is harsh and raises several challenges with respect to corrosion control. In this invited review paper, the body environment is analysed in detail and the possible effects of the corrosion of different biomaterials on biocompatibility are discussed. Then, the kinetics of corrosion, passivity, its breakdown and regeneration in vivo are conferred. Next, the mostly used metallic biomaterials and their corrosion performance are reviewed. These biomaterials include stainless steels, cobalt-chromium alloys, titanium and its alloys, Nitinol shape memory alloy, dental amalgams, gold, metallic glasses and biodegradable metals. Then, the principles of implant failure, retrieval and failure analysis are highlighted, followed by description of the most common corrosion processes in vivo. Finally, approaches to control the corrosion of metallic biomaterials are highlighted.

Synthesis of calcium-deficient hydroxyapatite nanowires and nanotubes performed by template-assisted electrodeposition

Hydroxyapatite (HA) has received much interest for being used as bone substitutes because of its similarity with bioapatites. In form of nanowires or nanotubes, HA would offer more advantages such as better biological and mechanical properties than conventional particles (spherical). To date, no study had allowed the isolated nanowires production with simultaneously well-controlled morphology and size, narrow size distribution and high aspect ratio (length on diameter ratio). So, it is impossible to determine exactly the real impact of particles' size and aspect ratio on healing responses of bone substitutes and characteristics of these ones; their biological and mechanical effects can never be reproducible. By the template-assisted pulsed electrodeposition method, we have for the first time succeeded to obtain such calcium-deficient hydroxyapatite (CDHA) particles in aqueous baths with hydrogen peroxide by both applying pulsed current density and pulsed potential in cathodic electrodeposition. After determining the best conditions for CDHA synthesis on gold substrate in thin films by X-ray diffraction (XRD) and Energy dispersive X-ray spectroscopy (EDX), we have transferred those conditions to the nanowires and nanotubes synthesis with high aspect ratio going until 71 and 25 respectively. Polycrystalline CDHA nanowires and nanotubes were characterized by Scanning electron microscopy (SEM) and Transmission electron microscopy (TEM). At the same time, this study enabled to understand the mechanism of nanopores filling in gold covered polycarbonate membrane: here a preferential nucleation on gold in membranes with 100 and 200 nm nanopores diameters forming nanowires whereas a preferential and randomly nucleation on nanopores walls in membranes with 400 nm nanopores diameter forming nanotubes.

Atomically resolved calcium phosphate coating on a gold substrate

Some articles have revealed that the electrodeposition of calcium phosphate (CaP) coatings entails a precursor phase, similarly to biomineralization in vivo. The chemical composition of the initial layer and its thickness are, however, still arguable, to the best of our knowledge. Moreover, while CaP and electrodeposition of metal coatings have been studied utilizing atom-probe tomography (APT), the electrodeposition of CaP ceramics has not been heretofore studied. Herein, we present an investigation of the CaP deposition on a gold substrate. Using APT and transmission electron microscopy (TEM) it is found that a mixture of phases, which could serve as transient precursor phases to hydroxyapatite (HAp), can be detected. The thickness of these phases is tens of nanometers, and they consist of amorphous CaP (ACP), dibasic calcium phosphate dihydrate (DCPD), and octacalcium phosphate (OCP). This demonstrates the value of using atomic-resolved characterization techniques for identifying the precursor phases. It also indicates that the kinetics of their transformation into the more stable HAp is not too fast to enable their observation. The coating gradually displays higher Ca/P atomic ratios, a porous nature, and concomitantly a change in its density.

Calcium Phosphate Bioceramics: A Review of Their History, Structure, Properties, Coating Technologies and Biomedical Applications

Calcium phosphate (CaP) bioceramics are widely used in the field of bone regeneration, both in orthopedics and in dentistry, due to their good biocompatibility, osseointegration and osteoconduction. The aim of this article is to review the history, structure, properties and clinical applications of these materials, whether they are in the form of bone cements, paste, scaffolds, or coatings. Major analytical techniques for characterization of CaPs, in vitro and in vivo tests, and the requirements of the US Food and Drug Administration (FDA) and international standards from CaP coatings on orthopedic and dental endosseous implants, are also summarized, along with the possible effect of sterilization on these materials. CaP coating technologies are summarized, with a focus on electrochemical processes. Theories on the formation of transient precursor phases in biomineralization, the dissolution and reprecipitation as bone of CaPs are discussed. A wide variety of CaPs are presented, from the individual phases to nano-CaP, biphasic and triphasic CaP formulations, composite CaP coatings and cements, functionally graded materials (FGMs), and antibacterial CaPs. We conclude by foreseeing the future of CaPs.