Effect of a Nanostructured Titanium Surface on Gingival Cell Adhesion, Viability and Properties against P. gingivalis

TNF-α Activates NF-κB Signalling Pathway in MG-63 Cells on Titanium and Zirconia Implant Surfaces

Dental implant therapy is a widely used clinical procedure for restoring missing teeth in patients. Zirconia implants were introduced as an alternative to titanium implants due to their excellent biocompatibility and esthetic properties. The nuclear factor kappa B (NF-κB) signalling pathway is responsible for multiple aspects of innate and adaptive immune functions and serves as a significant and crucial mediator of inflammatory processes. The dysregulation of NF-κB activation induces pathological processes in multiple diseases. The purpose of this study was to investigate the activation of the NF-κB pathway upon stimulation with tumour necrosis factor (TNF)-α in osteoblast-like cells (MG-63) cultured on zirconia surfaces in comparison to titanium surfaces. Several methods such as immunoblot, immunofluorescence, MTT assay, and flow cytometry were used in this study. We observed that human recombinant TNF-α caused a strong activation of the NF-κB pathway on both zirconia and titanium discs and in wells without any discs. This activation was marked by the upregulation of MHC class I proteins in MG-63 cells grown on both titanium and zirconia discs; however, there was no effect on MHC class II protein expression. In summary, the present study has shown that TNF-α stimulation equally activates the NF-κB pathway in MG-63 cells cultured on both titanium and zirconia surfaces.

Copper doped hydroxyapatite nanocomposite thin films: synthesis, physico-chemical and biological evaluation

Cu-doped hydroxyapatite (CuHAp) thin films were obtained using spin coating method. To make these thin films, CuHAp suspensions obtained by sol-gel method were used. The coatings obtained were thermally treated at 500 °C. After the thermal treatment, the thin films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM). Moreover, the stability of the suspensions before being used to obtain the thin films was certified by dynamic light scattering (DLS), zeta potential methods and ultrasound measurements. In the XRD patterns, the peaks associated with hexagonal hydroxyapatite were identified in accordance with JCPDS no. 09-0432. EDS and XPS results confirmed the presence of Cu ions in the samples. Data about the morphological features and chemical composition of CuHAp thin films were obtained by performing scanning electron microscopy (SEM) measurements. Our results suggest that the CuHAp thin films surface is continuous and homogenous. The presence of the functional groups in the CuHAp thin films was confirmed by Fourier-transform infrared spectroscopy (FTIR) and Raman spectroscopy studies. Information about the surface topography of the CuHAp thin films has been obtained using atomic force microscopy (AFM). The AFM images determined that the surface topography of the CuHAp thin layer is homogenous and continuous without presenting any unevenness or fissures. The cytotoxicity of CuHAp thin films was assessed using human gingival fibroblasts (HGF-1) cells. The results of the cell viability assays demonstrated that the thin films presented good biocompatible properties towards the HGF-1 cells. Additionally, the adherence and development of HGF-1 cells on the surface of CuHAp thin films were determined using AFM. The AFM surface topographies highlighted that the CuHAp thin film's surface favored the attachment and proliferation of HGF-1 cells on their surface.

Effects of nanomodified titanium surfaces considering bacterial colonization and viability of osteoblasts and fibroblasts

This study investigates nanostructured titanium surfaces (Ti2 spikes) that promote the viability of osteoblasts and fibroblasts and prevent bacterial colonisation. Helium ion irradiation was adopted to produce nanometric-sized cones on titanium. Human osteoblasts (hFOB) and human gingiva fibroblasts (hGF) were used for analysis. A viability and a cytotoxicity assay were conducted to evaluate the lactate dehydrogenase (LDH) activity and assess cell damage in Ti2 spikes compared to titanium discs with a sandblasted and acid-etched (Ti2 SLA) surface. The antibacterial activity was investigated against Escherichia coli, Streptococcus mutans, Fusobacterium nucleatum, and Porphyromonas gingivalis. In the course of the cultivation, both hGF and hFOB demonstrated significantly reduced viability on the Ti2 spikes surface. hGF cells exhibited a slight but significant increase in LDH release. In contrast, hFOB showed reduced cytotoxicity on this surface. On the Ti2 spikes surface, hGF cells exhibited a significant reduction in gene expression of VCL, Src-1, and ITGα5. However, the integrin subunits ITGα1 and ITGα3 showed upregulation on the Ti2 spikes surface. The Ti2 spikes surface significantly increased the expression of almost all osteogenic markers. The results of conventional culturing demonstrated a statistically significant decrease in the number of viable cells for S. mutans, F. nucleaum, and greater quantities of P. gingivalis on Ti2 spikes surface compared to control. However, no such reduction was detected for E. coli. The long-term success of implants relies on establishing and maintaining hard and soft peri-implant tissues. Ti2 spikes represent a novel and promising approach to enhance osseointegration and optimize biocompatibility.

Effect of Er,Cr:YSGG Laser Irradiation on the Surface Modification and Cell Adhesion on Titanium Discs: An In Vitro Study

This study evaluates the potential of erbium, chromium-doped:yttrium, scandium, gallium, and garnet (Er,Cr:YSGG) laser irradiation to modify the titanium surface for optimal seeding of fibroblasts and osteoblasts in the treatment of peri-implantitis. Titanium discs were treated using the Er,Cr:YSGG laser, an ultrasonic device with a stainless tip, or titanium scalers. Changes in surface properties were analyzed by profilometer and scanning electron microscopy (SEM). Murine fibroblast and osteoblast adhesion and proliferation were evaluated qualitatively and quantitatively at 24 and 72 h. Profilometric surface topography and SEM showed that titanium scalers and ultrasonic debridement techniques significantly changed the structure of the machined and rough titanium surfaces. The Er,Cr:YSGG laser irradiation, on the other hand, did not alter titanium microstructures. The Er,Cr:YSGG laser irradiation with the 40 Hz group showed a significantly higher attached fibroblast cell numbers than the titanium scaler group at 72 h after treatment (p = 0.023). Additionally, the number of the attached osteoblasts in the Er,Cr:YSGG laser irradiation with the 40 Hz group was significantly higher than that of the no-treatment groups 24 h after treatment (p = 0.045). The Er,Cr:YSGG laser effectively promoted adherence of fibroblasts and osteoblasts to the titanium surface without significantly altering the titanium surface, suggesting its superiority for treating peri-implantitis.

A Comprehensive Review of the Contemporary Methods for Enhancing Osseointegration and the Antimicrobial Properties of Titanium Dental Implants

Titanium dental implants with various restorative options are popular for replacing missing teeth due to their comfortable fit, excellent stability, natural appearance, and impressive track record in clinical settings. However, challenges such as potential issues with osseointegration, peri-implant bone loss, and peri-implantitis might lead to implant failure, causing concern for patients and dental staff. Surface modification has the potential to significantly enhance the success rate of titanium implants and meet the needs of clinical applications. This involves the application of various physical, chemical, and bioactive coatings, as well as adjustments to implant surface topography, offering significant potential for enhancing implant outcomes in terms of osseointegration and antimicrobial properties. Many surface modification methods have been employed to improve titanium implants, showcasing the diversity of approaches in this field including sandblasting, acid etching, plasma spraying, plasma immersion ion implantation, physical vapor deposition, electrophoretic deposition, electrochemical deposition, anodization, microarc oxidation, laser treatments, sol-gel method, layer-by-layer self-assembly technology, and the adsorption of biomolecules. This article provides a comprehensive overview of the surface modification methods for titanium implants to address issues with insufficient osseointegration and implant-related infections. It encompasses the physical, chemical, and biological aspects of these methods to provide researchers and dental professionals with a robust resource to aid them in their study and practical use of dental implant materials, ensuring they are thoroughly knowledgeable and well-prepared for their endeavors.

Piranha-etched titanium nanostructure reduces biofilm formation in vitro

OBJECTIVES

Nano-modified surfaces for dental implants may improve gingival fibroblast adhesion and antibacterial characteristics through cell-surface interactions. The present study investigated how a nanocavity titanium surface impacts the viability and adhesion of human gingival fibroblasts (HGF-1) and compared its response to Porphyromonas gingivalis with those of marketed implant surfaces.

MATERIAL AND METHODS

Commercial titanium and zirconia disks, namely, sandblasted and acid-etched titanium (SLA), sandblasted and acid-etched zirconia (ZLA), polished titanium (PT) and polished zirconia (ZrP), and nanostructured disks (NTDs) were tested. Polished titanium disks were etched with a 1:1 combination of 98% H2SO4 and 30% H2O2 (piranha etching) for 5 h at room temperature to produce the NTDs. Atomic force microscopy was used to measure the surface topography, roughness, adhesion force, and work of adhesion. MTT assays and immunofluorescence staining were used to examine cell viability and adhesion after incubation of HGF-1 cells on the disk surfaces. After incubation with P. gingivalis, conventional culture, live/dead staining, and SEM were used to determine the antibacterial properties of NTD, SLA, ZLA, PT, and ZrP.

RESULTS

Etching created nanocavities with 10-20-nm edge-to-edge diameters. Chemical etching increased the average surface roughness and decreased the surface adherence, while polishing and flattening of ZrP increased adhesion. However, only the NTDs inhibited biofilm formation and bacterial adherence. The NTDs showed antibacterial effects and P. gingivalis vitality reductions. The HGF-1 cells demonstrated greater viability on the NTDs compared to the controls.

CONCLUSION

Nanocavities with 10-20-nm edge-to-edge diameters on titanium disks hindered P. gingivalis adhesion and supported the adhesion of gingival fibroblasts when compared to the surfaces of currently marketed titanium or zirconia dental implants.

CLINICAL RELEVANCE

This study prepared an effective antibacterial nanoporous surface, assessed its effects against oral pathogens, and demonstrated that surface characteristics on a nanoscale level influenced oral pathogens and gingival fibroblasts.

CLINICAL TRIAL REGISTRATION

not applicable.

Overview of strategies to improve the antibacterial property of dental implants

The increasing number of peri-implant diseases and the unsatisfactory results of conventional treatment are causing great concern to patients and medical staff. The effective removal of plaque which is one of the key causes of peri-implant disease from the surface of implants has become one of the main problems to be solved urgently in the field of peri-implant disease prevention and treatment. In recent years, with the advancement of materials science and pharmacology, a lot of research has been conducted to enhance the implant antimicrobial properties, including the addition of antimicrobial coatings on the implant surface, the adjustment of implant surface topography, and the development of new implant materials, and significant progress has been made in various aspects. Antimicrobial materials have shown promising applications in the prevention of peri-implant diseases, but meanwhile, there are some shortcomings, which leads to the lack of clinical widespread use of antimicrobial materials. This paper summarizes the research on antimicrobial materials applied to implants in recent years and presents an outlook on the future development.

Magnetic microspheres mimicking certain functions of macrophages: Towards precise antibacterial potency for bone defect healing

A variety of novel biomaterials have recently been developed to promote bone regeneration. However, the current biomaterials cannot accurately and effectively resist bacterial invasion. In this study, we constructed microspheres that mimic certain functions of macrophages as additives to bone repair materials, which can be manipulated as demanded to resist bacteria effectively and protect bone defect healing. Firstly, we prepared gelatin microspheres (GMSs) by an emulsion-crosslinking method, which were subsequently coated with polydopamine (PDA). Then, amino antibacterial nanoparticles obtained by a nanoprecipitation-self-assembly method and commercial amino magnetic nanoparticles were modified onto these PDA-coated GMSs to construct the functionalized microspheres (FMSs). The results showed that the FMSs possessed a rough topography and could be manipulated by a 100-400 ​mT static magnetic field to migrate directionally in unsolidified hydrogels. Moreover, in vitro experiments with near-infrared (NIR) showed that the FMSs had a sensitive and recyclable photothermal performance and could capture and kill Porphyromonas gingivalis by releasing reactive oxygen species. Finally, the FMSs were mixed with osteogenic hydrogel precursor, injected into the Sprague-Dawley rat periodontal bone defect of maxillary first molar (M1), and subsequently driven by magnetism to the cervical surface of M1 and the outer surface of the gel system for targeted sterilization under NIR, thus protecting the bone defect healing. In conclusion, the FMSs had excellent manipulation and antimicrobial performances. This provided us with a promising strategy to construct light-magnetism-responsive antibacterial materials to build a beneficial environment for bone defect healing.

Fabrication of a microfluidic device for probiotic drug's dosage screening: Precision Medicine for Breast Cancer Treatment

Breast cancer is the most common cancer in women; it has been affecting the lives of millions each year globally and microfluidic devices seem to be a promising method for the future advancements in this field. This research uses a dynamic cell culture condition in a microfluidic concentration gradient device, helping us to assess breast anticancer activities of probiotic strains against MCF-7 cells. It has been shown that MCF-7 cells could grow and proliferate for at least 24 h; however, a specific concentration of probiotic supernatant could induce more cell death signaling population after 48 h. One of our key findings was that our evaluated optimum dose (7.8 mg/L) was less than the conventional static cell culture treatment dose (12 mg/L). To determine the most effective dose over time and the percentage of apoptosis versus necrosis, flowcytometric assessment was performed. Exposing the MCF-7 cells to probiotic supernatant after 6, 24 and 48 h, confirmed that the apoptotic and necrotic cell death signaling were concentration and time dependent. We have shown a case that these types of microfluidics platforms performing dynamic cell culture could be beneficial in personalized medicine and cancer therapy.

Cytokines Activate JAK-STAT Signaling Pathway in MG-63 Cells on Titanium and Zirconia

Although titanium has been traditionally used as the gold standard for dental implants, recent years have seen the widespread application of zirconia implants given their superiority with regards to reduced bacterial adhesion, inflammation and cellular-interaction in terms of bio-compatibility. The JAK-STAT signaling pathway plays an important role in bone remodeling and formation. The aim of the study was to investigate the activation of the JAK-STAT pathway through different cytokines in osteoblast-like cells (MG-63) on zirconia in comparison to titanium discs. IFN-γ induced the very strong activation of STAT1 protein, IFN-α activated both STAT1 and STAT3 molecules, IL-6 activated STAT3 and IL-4 induced the activation of STAT6 on both surfaces. The activation of STAT proteins was confirmed by western blot, immunofluorescence and flow cytometry using phospho-specific anti-STAT antibodies, which recognize only phosphorylated STAT proteins. The incubation of MG-63 cells with IFN-γ caused the upregulation of MHC class I and class II proteins when MG-63 cells were grown on zirconia and titanium discs. In sum, the present study shows that the JAK-STAT pathway is activated in MG-63 cells when they are incubated on titanium or zirconia surfaces.

How Porphyromonas gingivalis Navigate the Map: The Effect of Surface Topography on the Adhesion of Porphyromonas gingivalis on Biomaterials

The main purpose of this study is to develop an understanding of how Porphyromonas gingivalis responds to subperiosteal implant surface topography. A literature review was drawn from various electronic databases from 2000 to 2021. The two main keywords used were "Porphyromonas gingivalis" and "Surface Topography". We excluded all reviews and or meta-analysis articles, articles not published in English, and articles with no surface characterization process or average surface roughness (Ra) value. A total of 26 selected publications were then included in this study. All research included showed the effect of topography on Porphyromonas gingivalis to various degrees. It was found that topography features such as size and shape affected Porphyromonas gingivalis adhesion to subperiosteal implant materials. In general, a smaller Ra value reduces Porphyromonas gingivalis regardless of the type of materials, with a threshold of 0.3 µm for titanium.

Novel Dextran Coated Cerium Doped Hydroxyapatite Thin Films

Dextran coated cerium doped hydroxyapatite (Ca10-xCex(PO4)6(OH)2), with x = 0.05 (5CeHAp-D) and x = 0.1 (10CeHAp-D) were deposited on Si substrates by radio frequency magnetron sputtering technique for the first time. The morphology, composition, and structure of the resulting coatings were examined by scanning electron microscopy (SEM), energy-dispersive x-ray spectroscopy (EDX), atomic force microscopy (AFM), metallographic microscopy (MM), Fourier transform infrared spectroscopy (FTIR), and glow discharge optical emission spectroscopy (GDOES), respectively. The obtained information on the surface morphologies, composition and structure was discussed. The surface morphologies of the CeHAp-D composite thin films are smooth with no granular structures. The constituent elements of the CeHAp-D target were identified. The results of the FTIR measurements highlighted the presence of peaks related to the presence of ν1, ν3, and ν4 vibration modes of (PO43-) groups from the hydroxyapatite (HAp) structure, together with those specific to the dextran structure. The biocompatibility assessment of 5CeHAp-D and 10CeHAp-D composite coatings was also discussed. The human cells maintained their specific elongated morphology after 24 h of incubation, which confirmed that the behavior of gingival fibroblasts and their proliferative capacity were not disturbed in the presence of 5CeHAp-D and 10CeHAp-D composite coatings. The 5CeHAp-D and 10CeHAp-D coatings' surfaces were harmless to the human gingival fibroblasts, proving good biocompatibility.

Novel Titanium Nanospike Structure Using Low-Energy Helium Ion Bombardment for the Transgingival Part of a Dental Implant

AIM(S)

The aim of the study was to fabricate a nanospike surface on a titanium alloy surface using a newly established method of low-energy helium ion bombardment. Various methods to achieve nanospike formation on titanium have been introduced recently, and their antibacterial properties have been mainly investigated with respect to Escherichia coli and Staphylococcus aureus. Oral pathogens such as Porphyromonas gingivalis play an important role in the development of peri-implantitis. For that reason, the antibacterial properties of the novel, nanostructured titanium surface against P. gingivalis were assessed, and a possible effect on the viability of gingival fibroblasts was evaluated.

MATERIALS AND METHODS

Helium sputtering was employed for developing titanium surfaces with nanospikes of 500 nm (ND) in height; commercially available smooth-machined (MD) and sandblasted and acid-etched titanium disks (SLA) were used as controls. Surface structure characterization was performed through scanning electron microscopy (SEM) and atomic force microscopy (AFM). Following incubation with P. gingivalis, antibacterial properties were determined via conventional culturing and SEM. Additionally, the viability of human gingival fibroblasts (HGFs) was tested through MTT assay, and cell morphology was assessed through SEM.

RESULTS

SEM images confirmed the successful establishment of a nanospike surface with required heights, albeit with heterogeneity. AFM images of the 500 nm nanospike surface revealed that the roughness is dominated by large-scale hills and valleys. For frame sizes of 5 × 5 μm and smaller, the average roughness is dominated by the height of the titanium spikes. ND successfully induces dysmorphisms within P. gingivalis cultures following the incubation period, while conventional culturing reveals a 17% and 20% reduction for ND compared to MD and SLA, respectively. Moreover, the nanospike surfaces did not affect the viability of human growth fibroblasts despite their sharp surface.

CONCLUSION(S)

This study successfully developed a novel titanium-nanospike-based structuration technique for titanium surfaces. In addition, the nanospikes did not hinder gingival fibroblast viability. Enhanced antimicrobial effects for such a novel nanospike-based resurfacing technique can be achieved through further optimizations for nanospike spacing and height parameters.

Relevant Aspects of Piranha Passivation in Ti6Al4V Alloy Dental Meshes

Passivation of titanium alloy dental meshes cleans their surface and forms a thin layer of protective oxide (TiO2) on the surface of the material to improve resistance to corrosion and prevent release of ions to the physiological environment. The most common chemical agent for the passivation process of titanium meshes is hydrochloric acid (HCl). In this work, we introduce the use of Piranha solution (H2SO4 and H2O2) as a passivating and bactericidal agent for metallic dental meshes. Meshes of grade 5 titanium alloy (Ti6Al4V) were tested after different treatments: as-received control (Ctr), passivated by HCl, and passivated by Piranha solution. Physical-chemical characterization of all treated surfaces was carried out by scanning electron microscopy (SEM), confocal microscopy and sessile drop goniometry to assess meshes’ topography, elemental composition, roughness, wettability and surface free energy, that is, relevant properties with potential effects for the biological response of the material. Moreover, open circuit potential and potentiodynamic tests were carried out to evaluate the corrosion behavior of the differently-treated meshes under physiological conditions. Ion release tests were conducted using Inductively Coupled Plasma mass spectrometry (ICP-MS). The antibacterial activity by prevention of bacterial adhesion tests on the meshes was performed for two different bacterial strains, Pseudomonas aeruginosa (Gram-) and Streptococcus sanguinis (Gram+). Additionally, a bacterial viability study was performed with the LIVE/DEAD test. We complemented the antibacterial study by counting cells attached to the surface of the meshes visualized by SEM. Our results showed that the passivation of titanium meshes with Piranha solution improved their hydrophilicity and conferred a notably higher bactericidal activity in comparison with the meshes passivated with HCl. This unique response can be attributed to differences in the obtained nanotextures of the TiO2 layer. However, Piranha solution treatment decreased electrochemical stability and increased ion release as a result of the porous coating formed on the treated surfaces, which can compromise their corrosion resistance. Framed by the limitations of this work, we conclude that using Piranha solution is a viable alternative method for passivating titanium dental meshes with beneficial antibacterial properties that merits further validation for its translation as a treatment applied to clinically-used meshes.