XPS, AES and SEM analysis of recent dental implants

Surface Topography Has Less Influence on Peri-Implantitis than Patient Factors: A Comparative Clinical Study of Two Dental Implant Systems

OBJECTIVES

This study aims to assess the risk of peri-implantitis (PI) onset among different implant systems and evaluate the severity of the disease from a population of patients treated in a university clinic. Furthermore, this study intends to thoroughly examine the surface properties of the implant systems that have been identified and investigated.

MATERIAL AND METHODS

Data from a total of six hundred and 14 patients were extracted from the Institute of Clinical Dentistry, Dental Faculty, University of Oslo. Subject- and implant-based variables were collected, including the type of implant, date of implant installation, medical records, recall appointments up to 2022, periodontal measurements, information on diabetes, smoking status, sex, and age. The outcome of interest was the diagnosis of PI, defined as the occurrence of bleeding on probing (BoP), peri-implant probing depth (PD) ≥ 5 mm, and bone loss (BL). Data were analyzed using multivariate linear and logistic regression. Scanning electron microscopy, light laser profilometer, and X-ray photoelectron spectroscopy were utilized for surface and chemical analyses.

RESULTS

Among the patients evaluated, 6.8% were diagnosed with PI. A comparison was made between two different implant systems: Dentsply Sirona, OsseospeedTM and Straumann SLActive, with mean follow-up times of 3.84 years (SE: 0.15) and 3.34 years (SE: 0.15), respectively. The surfaces have different topographies and surface chemistry. However, no significant association was found between PI and implant surface/system, including no difference in the onset or severity of the disease. Nonetheless, plaque control was associated with an increased risk of developing PI, along with the gender of the patient. Furthermore, patients suffering from PI exhibited increased BL in the anterior region.

CONCLUSION

No differences were observed among the evaluated implant systems, although the surfaces have different topography and chemistry. Factors that affected the risk of developing PI were plaque index and male gender. The severity of BL in patients with PI was more pronounced in the anterior region. Consequently, our findings show that success in implantology is less contingent on selecting implant systems and more on a better understanding of patient-specific risk factors, as well as on implementing biomaterials that can more effectively debride dental implants.

Biofouling on titanium implants: a novel formulation of poloxamer and peroxide for in situ removal of pellicle and multi-species oral biofilm

Eradicating biofouling from implant surfaces is essential in treating peri-implant infections, as it directly addresses the microbial source for infection and inflammation around dental implants. This controlled laboratory study examines the effectiveness of the four commercially available debridement solutions '(EDTA (Prefgel®), NaOCl (Perisolv®), H2O2 (Sigma-Aldrich) and Chlorhexidine (GUM® Paroex®))' in removing the acquired pellicle, preventing pellicle re-formation and removing of a multi-species oral biofilm growing on a titanium implant surface, and compare the results with the effect of a novel formulation of a peroxide-activated 'Poloxamer gel (Nubone® Clean)'. Evaluation of pellicle removal and re-formation was conducted using scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy to assess the surface morphology, elemental composition and chemical surface composition. Hydrophilicity was assessed through contact angle measurements. The multi-species biofilm model included Streptococcus oralis, Fusobacterium nucleatum and Aggregatibacter actinomycetemcomitans, reflecting the natural oral microbiome's complexity. Biofilm biomass was quantified using safranin staining, biofilm viability was evaluated using confocal laser scanning microscopy, and SEM was used for morphological analyses of the biofilm. Results indicated that while no single agent completely eradicated the biofilm, the 'Poloxamer gel' activated with 'H2O2' exhibited promising results. It minimized re-contamination of the pellicle by significantly lowering the contact angle, indicating enhanced hydrophilicity. This combination also showed a notable reduction in carbon contaminants, suggesting the effective removal of organic residues from the titanium surface, in addition to effectively reducing viable bacterial counts. In conclusion, the 'Poloxamer gel + H2O2' combination emerged as a promising chemical decontamination strategy for peri-implant diseases. It underlines the importance of tailoring treatment methods to the unique microbial challenges in peri-implant diseases and the necessity of combining chemical decontaminating strategies with established mechanical cleaning procedures for optimal management of peri-implant diseases.

Osseointegration of implant surfaces in metabolic syndrome and type-2 diabetes mellitus

This in vivo study evaluated the bone healing response around endosteal implants with varying surface topography/chemistry in a preclinical, large transitional model induced with metabolic syndrome (MS) and type-2 diabetes mellitus (T2DM). Fifteen Göttingen minipigs were randomly distributed into two groups: (i) control (normal diet, n = 5) and (ii) O/MS (cafeteria diet for obesity induction, n = 10). Following obesity induction, five minipigs from the obese/metabolic syndrome (O/MS) group were further allocated, randomly, into the third experimental group: (iii) T2DM (cafeteria diet + streptozotocin). Implants with different surface topography/chemistry: (i) dual acid-etched (DAE) and (ii) nano-hydroxyapatite coating over the DAE surface (NANO), were placed into the right ilium of the subjects and allowed to heal for 4 weeks. Histomorphometric evaluation of bone-to-implant contact (%BIC) and bone area fraction occupancy (%BAFO) within implant threads were performed using histomicrographs. Implants with NANO surface presented significantly higher %BIC (~26%) and %BAFO (~35%) relative to implants with DAE surface (%BIC = ~14% and %BAFO = ~28%, p < .025). Data as a function of systemic condition presented significantly higher %BIC (~28%) and %BAFO (~42%) in the control group compared with the metabolically compromised groups (O/MS: %BIC = 14.35% and %BAFO = 26.24%, p < .021; T2DM: %BIC = 17.91% and %BAFO = 26.12%, p < .021) with no significant difference between O/MS and T2DM (p > .05). Statistical evaluation considering both factors demonstrated significantly higher %BIC and %BAFO for the NANO surface relative to DAE implant, independent of systemic condition (p < .05). The gain increase of %BIC and %BAFO for the NANO compared with DAE was more pronounced in O/MS and T2DM subjects. Osseointegration parameters were significantly reduced in metabolically compromised subjects compared with healthy subjects. Nanostructured hydroxyapatite-coated surfaces improved osseointegration relative to DAE, regardless of systemic condition.

Comparison of Roughness, Wettability, and SEM Features between Sandblasted Acid-Etched and Oxidized Titanium Dental Implants

The surface of dental implants has undergone multiple modifications across the timeline to enhance osseointegration, thereby enhancing the success of dental implants. This study compared the surface roughness, wettability and topography of sandblasted acid-etched, and oxidized titanium dental implants. Three commercially available implants-namely, SLA, SLActive, and TiUnite-were evaluated for surface roughness in terms of Ra, Rq, and Rz; wettability in terms of contact angle (CA); and topography using scanning electron microscopy (SEM). Roughness and wettability values were compared between the three surfaces by ANOVA and pairwise comparison by Tukey's HSD post hoc testing using SPSS Software. A p value of < 0.01 was considered to be statistically significant. The TiUnite surface exhibited the highest roughness values (Ra = 1.91 ± 0.006 μm, Rq = 2.99 ± 0.005 μm, Rz = 8.37 ± 0.003 μm) followed by the SLA and SLActive surfaces. The contact angles of the SLA, SLActive, and TiUnite dental implants were 98.44 ± 0.52°, 9 ± 0.03°, and 94.39 ± 0.08°, respectively. These data demonstrated statistically significant differences between the three surfaces (p < 0.01). There were no distinct differences in SEM features between the SLA and SLActive surfaces. However, the TiUnite surface exhibited a distinctly porous morphology. Oxidized dental implants differ from sandblasted acid-etched implants in terms of roughness, wettability, and surface topography.

In Vitro Characterization of an Anodized Surface of a Dental Implant Collar and Dental Abutment on Peri-Implant Cellular Response

The purpose of this paper was to determine the effect of anodization on the in vitro proliferation and adhesion of immortalized human keratinocytes (HaCats) and mouse bone marrow-derived mesenchymal stem cells (BM-MSCs) in Titanium Grade 23 (Ti6Al4V ELI) discs and to describe the surface topography, roughness, and composition of dental implants (body and collar) and abutments submitted to an area-specific anodization process. HaCat cells and BM-MSCs were seeded onto discs with three different surface treatments: machined, area-specific anodization for abutments, and area-specific anodization for implant collars. Cell proliferation was assessed using a resazurin-based fluorescent dye on days 1, 3, and 7, while cell adhesion was examined using scanning electron microscopy (SEM). Surface topography, roughness, and composition were evaluated for six implant bodies with an anodized rough surface, six anodized implant smooth collars, and six anodized prosthetic abutments. Both HaCats and BM-MSCs showed increased viability over time (p < 0.001) with no statistically significant differences among the different surfaces (p = 0.447 HaCats and p = 0.631 BM-MSCs). SEM analysis revealed an enhanced presence and adhesion of HaCat cells on the anodized surface for the implant collars and an increased adhesion of BM-MSCs on both the anodized and machined surface abutments. The topography characteristics of the treated implants and abutments varied depending on the specific implant region. Chemical analysis confirmed the presence of oxygen, calcium, phosphorus, and sodium on the anodized surfaces. The area-specific anodization process can be utilized to create variable topography, increase the specific surface area, and introduce oxygen, calcium, phosphorus, and sodium to dental implants and abutments. While BM-MSCs and HaCat cells showed similar adhesion and proliferation on anodized and machined surfaces, a positive interaction between anodized Ti6Al4V ELI surfaces and these two cell lines present in the peri-implant mucosa was observed. Due to the limitations of the present study, further research is necessary to confirm these findings.

Effects of Surface Treatment Method Forming New Nano/Micro Hierarchical Structures on Attachment and Proliferation of Osteoblast-like Cells

Titanium (Ti) and Ti-based alloys are commonly used in dental implants, and surface modifications of dental implants are important for achieving osseointegration (i.e., direct connection between the implant surface and bone). This study investigated the effect of an eco-friendly etching solution-a hydrogen peroxide-sodium bicarbonate mixture-on the surface properties and contact angles of osteoblast adhesion and proliferation on Ti surfaces. Disk-shaped Ti specimens were prepared using different surface treatments (machining, sandblasting, and sandblasting/acid-etching), and they were immersed in the etching solution and ultrasonically cleaned. Surface characterization was performed using scanning electron microscopy, digital microscopy, contact angle analysis, and X-ray photoelectron spectroscopy. MG-63 osteoblasts were cultured on the specimens, and their adhesion to the specimen surface and proliferation were examined using staining and the MTT assay, respectively. Additional etching with the etching solution caused the formation of nano/micro hierarchical structures, increased surface roughness, and enhanced hydrophilicity. Osteoblast adhesion and proliferation were found to improve on the modified surfaces. The eco-friendly etching method has the potential to enhance the biological properties of Ti implant surfaces and thereby improve dental implant performance.

The Effect of Titanium Surface Topography on Adherent Macrophage Integrin and Cytokine Expression

Immunomodulatory biomaterials have the potential to stimulate an immune response able to promote constructive and functional tissue remodeling, as opposed to persistent inflammation and scar tissue formation. This study examined the effects of titanium surface modification on integrin expression and concurrent cytokine secretion by adherent macrophages in vitro in an attempt to delineate the molecular events involved in biomaterial-mediated immunomodulation. Non-polarised (M0) and inflammatory polarised (M1) macrophages were cultured on a relatively smooth (machined) titanium surface and two proprietary modified rough titanium surfaces (blasted and fluoride-modified) for 24 h. The physiochemical characteristics of the titanium surfaces were assessed by microscopy and profilometry, while macrophage integrin expression and cytokine secretion were determined using PCR and ELISA, respectively. After 24 h adhesion onto titanium, integrin α1 expression was downregulated in both M0 and M1 cells on all titanium surfaces. Expression of integrins α2, αM, β1 and β2 increased in M0 cells cultured on the machined surface only, whereas in M1 cells, expression of integrins α2, αM and β1 all increased with culture on both the machined and rough titanium surfaces. These results correlated with a cytokine secretory response whereby levels of IL-1β, IL-31 and TNF-α increased significantly in M1 cells cultured on the titanium surfaces. These results show that adherent inflammatory macrophages interact with titanium in a surface-dependent manner such that increased levels of inflammatory cytokines IL-1β, TNF-α and IL-31 secreted by M1 cells were associated with higher expression of integrins α2, αM and β1.

Assessing the Cleanliness of Dental Implants Using Scanning Electron Microscopy and Energy-Dispersive X-ray Spectroscopy Analysis-A SEM and EDS In Vitro Study

A wide variety of titanium (Ti) alloy dental implant systems are available and as a result, choosing the correct system has become a challenge. Cleanliness of the dental implant surface affects osseointegration but surface cleanliness may be jeopardized during manufacturing. The purpose of this study was to assess the cleanliness of three implant systems. Fifteen implants per system were examined with scanning electron microscopy to identify and count foreign particles. Particle chemical composition analysis was performed with energy-dispersive X-ray spectroscopy. Particles were categorized according to size and location. Particles on the outer and inner threads were quantitatively compared. A second scan was performed after exposing the implants to room air for 10 min. Carbon, among other elements, was found on the surface of all implant groups. Zimmer Biomet dental implants had higher particle numbers than other brands. Cortex and Keystone dental implants showed similar distribution patterns. The outer surface had higher particle numbers. Cortex dental implants were the cleanest. The change in particle numbers after exposure was not significant (p > 0.05). Conclusion: Most of the implants studied were contaminated. Particle distribution patterns vary with the manufacturer. The wider and outer areas of the implant have a higher probability of contamination.

In-Vitro Evaluation of Photofunctionalized Implant Surfaces in a High-Glucose Microenvironment Simulating Diabetics

The present study aimed to assess the efficacy of photofunctionalization on commercially available dental implant surfaces in a high-glucose environment. Discs of three commercially available implant surfaces were selected with various nano- and microstructural alterations (Group 1—laser-etched implant surface, Group 2—titanium–zirconium alloy surface, Group 3—air-abraded, large grit, acid-etched surface). They were subjected to photo-functionalization through UV irradiation for 60 and 90 min. X-ray photoelectron spectroscopy (XPS) was used to analyze the implant surface chemical composition before and after photo-functionalization. The growth and bioactivity of MG63 osteoblasts in the presence of photofunctionalized discs was assessed in cell culture medium containing elevated glucose concentration. The normal osteoblast morphology and spreading behavior were assessed under fluorescence and phase-contrast microscope. MTT (3-(4,5 Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) and alizarin red assay were performed to assess the osteoblastic cell viability and mineralization efficiency. Following photofunctionalization, all three implant groups exhibited a reduced carbon content, conversion of Ti4+ to Ti3+, increased osteoblastic adhesion, viability, and increased mineralization. The best osteoblastic adhesion in the medium with increased glucose was seen in Group 3. Photofunctionalization altered the implant surface chemistry by reducing the surface carbon content, probably rendering the surfaces more hydrophilic and conducive for osteoblastic adherence and subsequent mineralization in high-glucose environment.

Plasma of Argon Treatment of the Implant Surface, Systematic Review of In Vitro Studies

This paper aims to review the evidence of the cellular activity on titanium samples exposed to Plasma of Argon (PoA) treatment. A systematic review was carried out based on the PRISMA statement by searching the Cochrane Library, PubMed, Web of Science, EMBASE and Scopus, up to October 2020. Papers were selected according to PICOS format that is: Population (P): osteoblasts, fibroblasts, gingival cells; Intervention (I): PoA disinfection treatment; Comparison (C): untreated controls; Outcome (O): cell culture; Setting (S): in vitro assays. The quality assessment was performed according to the CRIS Guidelines (Checklist for Reporting In vitro Studies). A total of 661 articles were found, of which 16 were included. The quality assessment revealed an overall poor quality of the studies analyzed. In vitro studies on the potential of PoA showed a potential effect in promoting higher cell adhesion and protein adsorption in the earliest times (hours). This outcome was not so evident when later stages of cell growth on the surfaces were tested and compared to the control groups. Only one study was conducted in vivo on a human sample regarding abutment cleaning. No meta-analysis was conducted because of the variety of experimental settings, mixed methods and different cell lines studied. PoA seems to be effective in promoting cell adhesion and protein adsorption. The duration of this effect remains unclear. Further evidence is required to demonstrate the long-term efficacy of the treatment and to support the use of PoA treatment in clinical practice.

Analysis of the Chemical Composition and Morphological Characterization of Tissue Osseointegrated to a Dental Implant after 5 Years of Function

Osseointegration implies the coexistence of a biocompatible implant subjected to masticatory loads and living bone tissue adhered to its surface; this interaction is a critical process for the success of implants. The objective of this work is to analyze the osseoformation and osseointegration of a dental implant in operation for 5 years microscopically through morphological analysis of the surface and chemical composition through a variable pressure scanning electron microscope (VP-SEM) and energy dispersive X-ray spectrometry (EDX). The chemical composition and general characteristics of the structural morphology of random areas of the surfaces of an osseointegrated dental implant from an ex vivo sample were analyzed. On the surface of the implant free of bone tissue, titanium (TI) was mainly identified in the area of the implant threads and carbon (C) in the depth of the implant threads. Phosphorus (P), calcium (Ca), oxygen (O), carbon (C), with dense and homogeneous distribution, and, to a lesser extent, sodium (Na) were detected on the bone surface around the contour of the implant. Regarding the morphological characteristics of the implant surface, a rough structure with some irregularities and detachments of the implant lodged in the bone tissue was observed. Microscopic analysis showed calcified bone tissue distributed in an orderly manner on the coronal and medial surface and sinuous and irregular in the apical area, with the presence of red blood cells. The composition of the implant allows a dynamic process of bone remodeling and regeneration subject to the biological and mechanical needs of the operation. Dental implants are shown to have exceptional and long-lasting biocompatibility that enables the formation of mature peri-implant bone tissue.

Electroresponsive Performances of Ecoresorbable Smart Fluids Consisting of Various Plant-Derived Carrier Liquids

This paper proposes the fabrication of a new type of electrorheological (ER) fluid with ecoresorbable features as well as excellent electroresponsive performance. The proposed ER fluid consists of biocompatible Mg-doped silica/titania hollow nanoparticles (ST HNPs) suspended in vegetable oils (canola, grapeseed, olive, and soy). The effects of biodegradable plant-derived carrier liquids on the ER performance are analyzed. The polarizability and wettability of the fabricated ER fluids are studied. The high polarizability of the nanoparticles contributes to the highly electroresponsive performance by inducing electrostatic interactions between the nanoparticles under electric fields; this enables the formation of a rigid and strong fibril structure. A suitable wettability, which represents the favorable interaction between the oil and the nanoparticles, allows the nanoparticles to disperse evenly in the oil and prevents their aggregation, thereby making the formation of a rigid and strong fibrillar structure under the electric field easier.

Surface Activation of Titanium Dental Implants by Using UVC-LED Irradiation

Organic contaminants significantly limit the bioactivity of titanium implants, resulting in the degradation known as the ageing of titanium. To reactivate the surfaces, they can be photofunctionalized, i.e., irradiated with C-range ultraviolet (UVC) light. This descriptive in vitro study compares the effectiveness of novel light-emitting diode (LED) technology to remove contaminant hydrocarbons from three different commercially available titanium dental implants: THD, TiUnite, and SLA. The surface topography and morphology were characterized by scanning electron microscopy (SEM). The chemical compositions were analyzed by X-ray photoelectron spectroscopy (XPS), before and after the lighting treatment, by a pair of closely placed UVC (λ = 278 nm) and LED devices for 24 h. SEM analysis showed morphological differences at the macro- and micro-scopic level. XPS analysis showed a remarkable reduction in the carbon contents after the UVC treatment: from 25.6 to 19.5 C at. % (carbon atomic concentration) in the THD; from 30.2 to 20.2 C at. % in the TiUnite; from 26.1 to 19.2 C at. % in the SLA surface. Simultaneously, the concentration of oxygen and titanium increased. Therefore, LED-based UVC irradiation decontaminated titanium surfaces and improved the chemical features of them, regardless of the kind of surface.

Characterization of a Macro- and Micro-Textured Titanium Grade 5 Alloy Surface Obtained by Etching Only without Sandblasting

Our purpose was to physically characterize the surface, and the subsurface, of a macro- and micro-textured titanium grade 5 dental implant surface obtained by etching only, without sandblasting. The topography, surface roughness, as well as the surface structure and subsurface distribution of elements, were determined by scanning electronic microscopy (SEM), non-contact profilometry, X-ray diffraction (XRD), and a concentration profile performed by Auger electron spectroscopy (AES). The hydrogen concentration in the implants was measured; the ability to generate nanostructures when stored in deionized water was also investigated. Under SEM, the surface resembled a sandblasted and etched titanium surface with its typical macro- and micro-texture; roughness was moderate with average roughness (Sa) 1.29 µm. No titanium hydride was found at the implant surface and no enrichment of any alloying element was identified at the surface and subsurface. Hydrogen concentration was 79 ppm, within the normative tolerance (<130 ppm). After storage in water for 6 months, densely packed finger-like nanostructures were observed. The clinical advantage of this textured titanium alloy surface is that it displays the typical macro- and micro-features of a moderately rough sandblasted and etched (SLA) titanium surface without leaving behind any foreign sandblasting material.

Corrosion performance of various deformed surfaces of implant steel for coronary stent applications: Effect of protein concentration

This work was done to systematically elucidate the corrosion behavior of austenitic stainless steel subjected to various degree of cold deformation (10 %, 20 % & 30 %). The experiments were performed in phosphate buffer saline (PBS) solution having different concentrations of bovine serum albumin (0.2, 0.5, 1.0, 2.0, 4.0 g L^-1). Potentiodynamic polarization tests and electrochemical impedance spectroscopy (EIS) analysis were performed to obtain the corrosion parameters. Scanning electron microscopy with energy dispersive X-ray (SEM-EDX), atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS) were used to determine the surface morphologies and chemical compositions of the surface films. Contact angle analysis was also used to detect the hydrophilic character of sample surfaces. The BSA had a considerable effect of inhibition on the corrosion of SSs in annealed as well as in deformed state due to its adsorption on surface of steel. For annealed samples, at 4.0 g L^-1BSA concentration, the corrosion resistance was drastically decreased but interestingly not for sample with more than 10 % deformation and the concentration effect of BSA is also not very significant after 0.5 g L^-1 for deformed surfaces. The breakdown potential for 30 % deformed sample is quite higher in presence of BSA even at 4.0 g L^-1 while it is lowest for annealed samples in the same condition. The variation in contact angle with deformation is very less after adsorption of BSA. On the basis of the obtained results, mechanism aspect for corrosion of steel in presence of protein is also deliberated.

Decontamination of Ti Oxide Surfaces by Using Ultraviolet Light: Hg-Vapor vs. LED-Based Irradiation

C-range Ultraviolet (UVC) mercury (Hg)-vapor lamps have shown the successful decontamination of hydrocarbons and antimicrobial effects from titanium surfaces. This study focused on surface chemistry modifications of titanium dental implants by using two different light sources, Hg-vapor lamps and Light Emitting Diodes (LEDs), so as to compare the effectivity of both photofunctionalization technologies. Two different devices, a small Hg-vapor lamp (λ = 254 nm) and a pair of closely placed LEDs (λ = 278 nm), were used to irradiate the implants for 12 min. X-ray Photoelectron Spectroscopy (XPS) was employed to characterize the chemical composition of the surfaces, analysing the samples before and after the lighting treatment, performing a wide and narrow scan around the energy peaks of carbon, oxygen and titanium. XPS analysis showed a reduction in the concentration of surface hydrocarbons in both UVC technologies from around 26 to 23.4 C at.% (carbon atomic concentration). Besides, simultaneously, an increase in concentration of oxygen and titanium was observed. LED-based UVC photofunctionalization has been suggested to be as effective a method as Hg-vapor lamps to remove the hydrocarbons from the surface of titanium dental implants. Therefore, due to the increase in worldwide mercury limitations, LED-based technology could be a good alternative decontamination source.

Hydrodynamic control of titania nanotube formation on Ti-6Al-4V alloys enhances osteogenic differentiation of human mesenchymal stromal cells

In order to obtain bioactive bone-implant interfaces with enhanced osteogenic capacity, various approaches have been developed to modify surface physicochemical properties of bio-inert titanium and titanium alloys. One promising strategy involves fabricating highly ordered nanotubes (NT) on implant surfaces via electrochemical anodization. However, few studies have applied this technique to Ti-6Al-4V alloys most commonly adopted for the fabrication of osteo-integrated surfaces on orthopedic implants. In this study, we investigated the influence of electrolyte hydrodynamics to NT fabrication on Ti-6Al-4V in ethylene glycol based electrolyte and evaluated the osteogenic differentiation capacity of human mesenchymal stromal cells (hMSCs) on different diameter NT surfaces. Computational Fluid Dynamics (CFD) analysis was used to simulate electrolyte flow profiles under various stirring conditions (e.g. stirrer bar location and flow direction) and their correlation to NT formation. Polished Ti-6Al-4V disks (240 grit) were anodized at 20 and 40 V under optimal electrolyte flow conditions for comparison of NT diameter-controlled osteogenic differentiation and mineralization potential of hMSCs over 21 days culture in osteogenic media. Ti-6Al-4V surfaces anodized with 20 and 40 V resulted with NTs diameter approx. 39 and 83 nm, respectively. Electrolyte hydrodynamics (flow profile) significantly influenced the uniformity of NT formation. Here, a uniform velocity and shear stress profile at the surface promoted homogeneous NT growth, whereas large variation in either flow velocity or shear stress to the surface impaired mature NT formation. After 21 days of culture, fluorescence staining demonstrated significantly greater osteocalcin and osteopontin expression, and increased mineralized deposits (xylenol orange staining) on fluctuating NT surfaces anodized under 20 V (Ø 39 nm) relative to flat NT layer anodized with 40 V (Ø 83 nm) and polished controls. This study provides a systematic investigation of NT formation with respect to the electrolyte hydrodynamic effects to NT growth on Ti-6Al-4V alloys, demonstrating the feasibility of a one-step anodization process for generating uniform NT under optimal hydrodynamics. Optimized wavy micro-/nano-topography with Ø 39 nm NT stimulated osteogenic differentiation capacity of hMSCs on Ti-6Al-4V alloys and confirmed the potential application of anodization to improve osteo-integrative surfaces in orthopedic implants.

The Potential of a Nanostructured Titanium Oxide Layer with Self-Assembled Monolayers for Biomedical Applications: Surface Properties and Biomechanical Behaviors

This study investigated the surface properties and biomechanical behaviors of a nanostructured titanium oxide (TiO) layer with different self-assembled monolayers (SAMs) of phosphonate on the surface of microscope slides. The surface properties of SAMs were analyzed using scanning electron microscopy, X-ray photoemission spectroscopy, and contact angle goniometry. Biomechanical behaviors were evaluated using nanoindentation with a diamond Berkovich indenter. Analytical results indicated that the homogenous nanostructured TiO surface was formed on the substrate surface after the plasma oxidation treatment. As the TiO surface was immersed with 11-phosphonoundecanoic acid solution (PUA-SAM/TiO), the formation of a uniform SAM can be observed on the sample surface. Moreover, the binding energy of O 1s demonstrated the presence of the bisphosphonate monolayer on the SAMs-coated samples. It was also found that the PUA-SAM/TiO sample not only possessed a higher wettability performance, but also exhibited low surface contact stiffness. A SAM surface with a high wettability and low contact stiffness could potentially promote biocompatibility and prevent the formation of a stress shielding effect. Therefore, the self-assembled technology is a promising approach that can be applied to the surface modification of biomedical implants for facilitating bone healing and osseointegration.

Human Osteoblast Cell Behaviour on Titanium Discs Treated with Argon Plasma

(1) Background. Titanium is characterized by its biocompatibility and resistance to stress and fatigue. Treatment with argon plasma may favour growth of human osteoblasts with respect to cell adhesion and proliferation. The aim of this study was to analyse the behaviour of human osteoblasts (MG-63) on Grade IV and V titanium possessing a sand-blasted, acid-etched (SLA) surface. SLA is a widely used surface treatment to create micro- and macroretentions to enhance osteoconductive properties on the surface. (2) Methods. One group of each grade of titanium was decontaminated with argon plasma and compared. On each disc, 20 × 10⁴ cells were cultivated for morphological analysis, study of cell viability (regarding a negative control [100% viability]) and mitochondrial energy balance. (3) Results. At 24 h titanium treated with SLA showed a higher percentage of cell viability (47.3 ± 8.1%) compared to titanium IV treated with argon plasma, which presented a percentage of 79.1 ± 1.1%. Grade V titanium treated with argon plasma presented a higher viability percentage 91.3 ± 3.0% whereas nontreated Grade V titanium presented 53.3 ± 4.0%. Cells cultivated on the surfaces with an argon-plasma treatment were enlarged in comparison to non-treated discs. The cells with smaller circularity with a greater spread and spindle shape were the ones cultivated on the Grade V titanium surface. Cells seeded on treated titanium IV and titanium V, treated or not, showed higher mitochondrial activity over nontreated titanium IV. (4) Conclusions. Cells cultivated on those Grade V titanium discs that were decontaminated with argon plasma presented higher levels of cell adhesion and proliferation, lower mitochondrial damage and a higher mean cell area compared to those not decontaminated with argon plasma.

The chemical surface evaluation of black and white porous titanium granules and different commercial dental implants with energy-dispersive x-ray spectroscopy analysis

BACKGROUND

The chemical surface structure of the porous titanium grafts has not been found to study in the literature on the similarity of chemical surfaces of different commercial dental implants.

PURPOSE

The purpose of this study is to investigate the chemical composition and surface energies of white (WPTG) and black porous titanium granules (PTG) by energy dispersive x-ray spectrometry (EDX) analysis to compare with different commercial dental implant surface.

MATERIALS AND METHODS

The surface chemical compositions of six commercially available dental implants with different surface structures, PTG and WPTG were examined by EDX analysis. Surface analyzes were performed on the apical, middle, and coronal parts of each implant and on the top, flank, and valley regions on each side. Surface analyzes of dental implants were evaluated at ×200 and ×2000 magnifications. The EDX evaluation of PTG grafts were evaluated at ×250, ×2000, ×5000, and ×50 000 magnifications.

RESULTS

PTG grafts showed elements of Na (8.88 ± 9.98%), Cl (2.44 ± 1.96%), and Al (0.99 ± 0.37%) as well as Ti (90.06 ± 11.34%) molecule at ×5000 magnification. In WPTG, Ti (%34.55 ± 6.41%) and O (%65.44 ± 6.42%) molecules were detected.

CONCLUSIONS

It has been found that PTG surface was not made of pure titanium, it has different chemical molecules at larger magnifications. Cell culture and experimental studies are needed to establish a relationship between the different commercial implants and the surface structure of the titanium granules.

Covalently-Linked Hyaluronan versus Acid Etched Titanium Dental Implants: A Crossover RCT in Humans

Biochemical modification of titanium surfaces (BMTiS) entails immobilization of biomolecules to implant surfaces in order to induce specific host responses. This crossover randomized clinical trial assesses clinical success and marginal bone resorption of dental implants bearing a surface molecular layer of covalently-linked hyaluronan in comparison with control implants up to 36 months after loading. Patients requiring bilateral implant rehabilitation received hyaluronan covered implants in one side of the mouth and traditional implants in the other side. Two months after the first surgery, a second surgery was undergone to uncover the screw and to place a healing abutment. After two weeks, the operator proceeded with prosthetic procedures. Implants were evaluated by periapical radiographs and the crestal bone level was recorded at mesial and distal sites—at baseline and up to 36 months. One hundred and six implants were positioned, 52 HY-coated, and 48 controls were followed up. No differences were observed in terms of insertion and stability, wound healing, implant success, and crestal bone resorption at any time considered. All interventions had an optimal healing, and no adverse events were recorded. This trial shows, for the first time, a successful use in humans of biochemical-modified implants in routine clinical practice and in healthy patients and tissues with satisfactory outcomes.

Corrosion behaviour of austenitic stainless steels in phosphate buffer saline solution: synergistic effects of protein concentration, time and nitrogen

Adsorption of protein on a steel surface decreases the corrosion rate, while the formation of metal–protein complexes followed by detachment enhances the corrosion rate.

Eliminating the negative effect of cold deformation on the corrosion resistance of austenitic stainless steel in the presence of a protein

Interaction of proteins with stainless steel subjected to cold deformation. The presence of a protein overcomes the negative effect of martensite formation on corrosion due to its adsorption.

Superficial Characteristics of Titanium after Treatment of Chorreated Surface, Passive Acid, and Decontamination with Argon Plasma

(1) Background. Titanium is characterized by its biocompatibility, resistance to maximum stress, and fatigue and non-toxicity. The composition, surface structure, and roughness of titanium have a key and direct influence on the osseointegration processes when it is used in the form of dental implants. The objective of the present study is to characterize, at chemical, superficial, and biological levels, the result of the application of the sandblasted with large-grit and acid-etched (SLA) treatment consisting of coarse-grained and double-passivated acid blasting with subsequent decontamination with argon plasma on the surface of titanium implants type IV. (2) Methods. Four Oxtein^® dental implants (Zaragoza, Spain) were investigated with the following coding: Code L63713T (titanium grade IV, 3.75 mm in diameter, and 13 mm in length). The surface of the implants was SLA type obtained from coarse-grained, double passivated acid, and decontaminated with argon plasma. The samples were in their sealed packages and were opened in our laboratory. The X-ray photoelectron spectroscopy (XPS) technique was used to characterize the chemical composition of the surface, and the scanning electronic microscope (SEM) technique was used to perform topographic surface evaluation. Cell cultures were also performed on both surfaces. (3) Results. The superficial chemical analysis of the studied samples presented the following components, approximately, expressed in atomic percentage: O: 39%; Ti: 18%; C: 39%; N: 2%; and Si: 1%. In the same way, the topographic analysis values were obtained in the evaluated roughness parameters: R_a: 1.5 μm ± 0.02%; R_q: 1.31 μm ± 0.33; R_z: 8.98 μm ± 0.73; R_p: 5.12 μm ± 0.48; R_v: 3.76 μm ± 0.51; and R_c: 4.92 μm ± 0.24. At a biological level, the expression of osteocalcin was higher (p < 0.05) on the micro-rough surface compared to that machined at 48 and 96 h of culture. (4) Conclusions. The data obtained in our study indicate that the total carbon content, the relative concentration of titanium, and the roughness of the treatment performed on the implants are in agreement with those found in the literature. Further, the roughness of the treatment performed on the implants throws a spongy, three-dimensional surface suitable for bone growth on it. The biological results found are compatible with the clinical use of the surface tested.

Advanced inorganic nanocomposite for decontaminating titanium dental implants

Oral hygiene and regular maintenance are crucial for preserving good peri-implant health. However, available prophylaxis products and toothpastes, which are optimized for cleaning teeth, tend to contaminate and abrade implant surfaces due to their organic components and silica microparticles, respectively. This study aims to develop an organic-free implant-paste based on two-dimensional nanocrystalline magnesium phosphate gel and hydrated silica nanoparticles (20-30% w/w) for cleaning oral biofilm on titanium dental implants. The surface chemistry, morphology, and bacterial load of contaminated Ti disks before and after decontamination using prophylaxis brushing with toothpaste and implant-paste were characterized by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy, and fluorescence spectroscopy. Both commercial toothpastes and implant-paste remove bacteria, however, only implant-paste protects Ti metal from abrasion and removes organic contaminants. XPS showed a significant decrease of carbon contamination from 73% ± 2 to 20% ± 2 after mechanical brushing with implant-paste compared to 41% ± 11 when brushing with commercial toothpastes (p < 0.05). Fluorescence microscopy revealed that bacteria load on biofilm contaminated Ti (44 × 10³  ± 27 × 10³ /µm² ) was significantly reduced with the implant-paste to 2 × 10³  ± 1 × 10² /µm² and with a commercial toothpaste to 2.9 × 10³  ± 7·10² /µm² . This decay is relatively higher than the removal achieved using rotary prophylaxis brush alone (5 × 10³  ± 1 × 10³ /µm² , p < 0.05). Accordingly, this novel implant-paste shows a great promise as an efficient decontamination approach. © 2018 Wiley Periodicals, Inc. J. Biomed. Mater. Res. Part B, 2018. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 761-772, 2019.

High performance sol–gel synthesized Ce0.9Sr0.1(Zr0.53Ti0.47)O4sensing membrane for a solid-state pH sensor

We developed a high-performance solid-state pH sensor using a Ce_0.9Sr_0.1(Zr_0.53Ti_0.47)O₄(CSZT) membrane through a very simple sol–gel spin-coating process.

Release of titanium after insertion of dental implants with different surface characteristics - an ex vivo animal study

In the present study, amount of titanium (Ti) released into the surrounding bone during placement of implants with different surface structure was investigated. Quantification of Ti released during insertion from three different implants was performed in this ex vivo study. Jaw bone from pigs was used as model for installation of the implants and Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES) was used for analysis of the released Ti. Implant surface were examined with scanning electron microscopy (SEM), before and after the placement into the bone. Ti was abraded to the surrounding bone upon insertion of a dental implant and the surface roughness of the implant increased the amount of Ti found. Diameter and total area of the implant were of less importance for the Ti released to the bone. No visible damages to the implant surfaces could be identified in SEM after placement.

Hydrothermal Sterilization Improves Initial Osteoblast Responses on Sandpaper-Polished Titanium

Hydrocarbon contamination accumulated on titanium (Ti) implant surfaces during storage and sterilization is unavoidable and difficult to remove. It impairs the bioactivity of implants, restricts initial interactions between implants and the surrounding biological environment, and has become a common challenge for Ti implants. To overcome this problem, sterilization was considered as the final surface modification and a novel method, hydrothermal sterilization (HS), was proposed. Briefly, stored sandpaper-polished Ti specimens were sterilized in a glass container with pure water at 121 °C for 20 min and kept in the same water until utilization. As a control, another group of specimens was sterilized with conventional autoclaving (AC) at 121 °C for 20 min and stored in sterilization pouches after being dried at 60 °C. Compared with AC, HS deposited numerous nano-sized particles on the substrates, reduced the atomic percentage of the surface carbon, and transformed the Ti surface to a super hydrophilic status. HS also increased the attachment rate, spread, proliferation, and the mineralized nodule areas of rat bone marrow-derived osteoblasts. These results suggest that HS enhances the bioactivity of Ti implants for osteoblasts, and that this biofunctionalization was attributed to nanostructure construction, hydrophilic conversion, and the effective removal of hydrocarbons. Hydrothermal sterilization is proposed to be used as a universal sterilization method for all kinds of titanium implants without apatite coating.

TiO2nanotubes enriched with calcium, phosphorous and zinc: promising bio-selective functional surfaces for osseointegrated titanium implants

TiO₂nanotubes enriched with Ca, P, and Zn by reverse polarization anodization, are promising bio-selective functional structures for osseointegrated titanium implants.

Protein adsorption on a laser-modified titanium implant surface

PURPOSE

The aim of this study was to investigate the earlier phase of the osseointegration of a laser-treated implant surface in terms of human protein adsorption.

MATERIALS AND METHODS

Titanium surfaces were divided into machined (M), sandblasted (SB), and laser-treated (LT). The LT surfaces were created with an Nd diode-pumped laser in Q-switching, whereas the SB were treated with Al2O3. An x-ray photoelectron spectroscopy (XPS) analysis of titanium surface was performed. Titanium discs were used for albumin and fibronectin adsorption evaluation through fluorescence intensity. Fibronectin evaluation was also made with Western Blot analysis on experimental implants.

RESULTS

LT discs appeared to trigger a higher albumin and fibronectin adsorption with a regular pattern. The mean count of albumin adsorption was 0.29 and 3.8 for SB and LT, respectively (P = 0.016), whereas fibronectin values were 0.67 and 4.9 for (SB) and (LT) titanium (P = 0.02). XPS analysis showed that titanium, oxygen, carbon, and nitrogen were found on all 3 surfaces.

CONCLUSION

Laser-engineered porous titanium surface seems to promote, in vitro, the adsorption of albumin and fibronectin more than sandblasted (SB) or machined (M) implants.

Ultra-structural evaluation of an anodic oxidated titanium dental implant

Anodic oxidation is used for the surface treatment of commercial implants to improve their functional properties for clinical success. Here we conducted ultrastructural and chemical investigations into the micro- and nanostructure of the anodic oxide film of a titanium implant. The anodic oxidized layer of a Ti6Al4V alloy implant was examined ultrastructurally by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). They were also analyzed using energy dispersive X-ray spectrometry (EDS) and X-ray photoelectron spectroscopy (XPS). The TEM revealed that the oxide layer of the Ti6Al4V implant prepared through anodic oxidation was separated into two layers. Al and V were not present on the top surface of the anodic oxide. This can be attributed to the biocompatibility of the anodic oxidized Ti6Al4V alloy implant, because the release of harmful metal ions such as Al and V can be suppressed by the biocompatibility.

Self-assembled monolayers of alendronate on Ti6Al4V alloy surfaces enhance osteogenesis in mesenchymal stem cells

Phosphonates have emerged as an alternative for functionalization of titanium surfaces by the formation of homogeneous self-assembled monolayers (SAMs) via Ti-O-P linkages. This study presents results from an investigation of the modification of Ti6Al4V alloy by chemisorption of osseoinductive alendronate using a simple, effective and clean methodology. The modified surfaces showed a tailored topography and surface chemistry as determined by SEM microscopy and RAMAN spectroscopy. X-ray photoelectron spectroscopy revealed that an effective mode of bonding is created between the metal oxide surface and the phosphate residue of alendronate, leading to formation of homogenous drug distribution along the surface. In-vitro studies showed that alendronate SAMs induce differentiation of hMSC to a bone cell phenotype and promote bone formation on modified surfaces. Here we show that this novel method for the preparation of functional coatings on titanium-based medical devices provides osseoinductive bioactive molecules to promote enhanced integration at the site of implantation.

Decontamination of titanium implants using physical methods

OBJECTIVES

Current decontamination methods of titanium (Ti) implant present limited success in achieving predictable re-osseointegration. We hypothesized that even though these techniques could be useful in elimination of bacteria, they might be unsuccessful in removing organic contaminants and restoring the original surface composition. The aim of this study was to assess the effect of four decontamination methods on the surface chemistry and bacterial load of biofilm-contaminated implant surfaces in order to improve implant surface decontamination.

MATERIAL AND METHODS

The ability of clinically available methods such as metal and plastic curettes, Ti brushes and Er: YAG laser to decontaminate Ti implant surfaces was assessed. Surface morphology, chemical composition and properties of machined Ti discs (Ø 5.0 and 1.0 mm thick) were analysed before and after oral biofilm contamination using scanning electron microscope and X-ray photoelectron spectroscopy. The presence and viability of bacteria were evaluated with live-dead assays.

RESULTS

Biofilm contamination created an organic layer rich in hydrocarbons and bacteria that covered entirely the Ti surfaces. This organic layer has tightly adhered to Ti surfaces and could not be completely removed with any of the methods assessed. Ti brushes achieved greater elimination of organic contaminants and bacteria than curettes and Er: YAG laser; however, none of them was able to restore the original surface chemistry. Alternatively, Er: YAG laser-treated surfaces showed the lowest live-to-dead bacterial ratio.

CONCLUSIONS

Ti brushes were more effective than curettes (metal or plastic) and Er: YAG laser in decontaminating Ti implant surfaces, although none of these techniques was able to completely eliminate surface contamination. Er: YAG laser was more effective than curettes and Ti brushes in killing the biofilm bacteria.

Photofunctionalization of Titanium: An Alternative Explanation of Its Chemical-Physical Mechanism

Objectives

To demonstrate that titanium implant surfaces as little as 4 weeks from production are contaminated by atmospheric hydrocarbons. This phenomenon, also known as biological ageing can be reversed by UVC irradiation technically known as photofunctionalization. To propose a new model from our experimental evidence to explain how the changes in chemical structure of the surface will affect the adsorption of amino acids on the titanium surface enhancing osteointegration.

Methods

In our study XPS and AES were used to analyze the effects of UVC irradiation (photofunctionalization) in reversing biological ageing of titanium. SEM was used to analyze any possible effects on the topography of the surface.

Results

UVC irradiation was able to reverse biological ageing of titanium by greatly reducing the amount of carbon contamination present on the implant surface by up to 4 times, while the topography of the surface was not affected. UVC photon energy reduces surface H₂O and increases TiOH with many –OH groups being produced. These groups explain the super-hydrophilic effect from photofunctionalization when these groups come into contact with water.

Significance

Photofunctionalization has proven to be a valid method to reduce the amount of hydrocarbon contamination on titanium dental implants and improve biological results. The chemisorption mechanisms of amino acids, in our study, are dictated by the chemical structure and electric state present on the surface, but only in the presence of an also favourable geometrical composition at the atomical level.

Surface characterization and in vivo evaluation of laser sintered and machined implants followed by resorbable-blasting media process: A study in sheep

Background

This study aimed to compare the histomorphometric and histological bone response to laser-sintered implants followed by resorbable-blasting media (RBM) process relative to standard machined/RBM surface treated implants.

Material and Methods

Six male sheep (n=6) received 2 Ti-6Al-4V implants (1 per surface) in each side of the mandible for 6 weeks in vivo. The histomorphometric parameters bone-implant contact (BIC) and bone area fraction occupancy (BAFO) were evaluated.

Results

Optical interferometry revealed higher Sa and Sq values for the laser-sintered/RBM surface in relation to standard/RBM implants. No significant differences in BIC were observed between the two groups (p>0.2), but significantly higher BAFO was observed for standard/RBM implants (p<0.01).

Conclusions

The present study demonstrated that both surfaces were biocompatible and osseoconductive, and the combination of laser sintering and RBM has no advantage over the standard machined implants with subsequent RBM.

Key words:Dental implants, osseointegration, resorbable- blasting media, sheep, in vivo.