Implant surface factors and bacterial adhesion: a review of the literature

Characterizing Surface Morphological and Chemical Properties of Commonly Used Orthopedic Implant Materials and Determining Their Clinical Significance

The goal of the study was to compare the surface characteristics of typical implant materials used in orthopedic surgery and traumatology, as these determine their successful biointegration. The morphological and chemical structure of Vortex plate anodized titanium from commercially pure (CP) Grade 2 Titanium (Ti2) is generally used in the following; non-cemented total hip replacement (THR) stem and cup Ti alloy (Ti6Al4V) with titanium plasma spray (TPS) coating; cemented THR stem Stainless steel (SS); total knee replacement (TKR) femoral component CoCrMo alloy (CoCr); cemented acetabular component from highly cross-linked ultrahigh molecular weight polyethylene (HXL); and cementless acetabular liner from ultrahigh molecular weight polyethylene (UHMWPE) (Sanatmetal, Ltd., Eger, Hungary) discs, all of which were examined. Visualization and elemental analysis were carried out by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS). Surface roughness was determined by atomic force microscopy (AFM) and profilometry. TPS Ti presented the highest Ra value (25 ± 2 μm), followed by CoCr (535 ± 19 nm), Ti2 (227 ± 15 nm) and SS (170 ± 11 nm). The roughness measured in the HXL and UHMWPE surfaces was in the same range, 147 ± 13 nm and 144 ± 15 nm, respectively. EDS confirmed typical elements regarding the investigated prosthesis materials. XPS results supported the EDS results and revealed a high % of Ti4+ on Ti2 and TPS surfaces. The results indicate that the surfaces of prosthesis materials have significantly different features, and a detailed characterization is needed to successfully apply them in orthopedic surgery and traumatology.

Impact of surface characteristics on the peri-implant microbiome in health and disease

BACKGROUND

Because little is known about the impact of implant surface modifications on the peri-implant microbiome, we aimed to examine peri-implant communities in various surface types in order to better understand the impact of these surfaces on the development of peri-implantitis (PI).

METHODS

One hundred and six systemically healthy individuals with anodized (AN), hydroxyapatite-coated (HA), or sandblasted acid-etched (SLA) implants that were >6 months in function were recruited and categorized into health (H) or PI. Peri-implant biofilm was analyzed using 16S rRNA gene sequencing and compared between health/disease and HA/SLA/AN using community-level and taxa-level metrics.

RESULTS

Healthy implants did not demonstrate significant differences in clustering, alpha- or beta-diversity based on surface modification. AN and HA surfaces displayed significant differences between health and PI (p < 0.05); however, such a clustering was not evident with SLA (p > 0.05). AN and HA surfaces also differed in the magnitude and diversity of differences between health and PI. Six species belonging to the genera Shuttleworthia, Scardovia, and Prevotella demonstrated lower abundances in AN implants with PI, and 18 species belonging to the genera Fretibacterium, Tannerella, Treponema, and Fusobacterium were elevated, while in HA implants with PI, 20 species belonging to the genera Streptococcus, Lactobacillus, Veillonella, Rothia, and family Ruminococcaceae were depleted and Peptostreptococcaceae, Atopobiaceae, Veillonellaceae, Porphyromonadaceae, Desulfobulbaceae, and order Synergistales were enriched.

CONCLUSIONS

Within the limitations of this study, we demonstrate that implant surface can differentially modify the disease-associated microbiome, suggesting that surface topography must be considered in the multi-factorial etiology of peri-implant diseases.

Influence of nanosecond laser surface patterning on dental 3Y-TZP: Effects on the topography, hydrothermal degradation and cell response

OBJECTIVES

Laser surface micropatterning of dental-grade zirconia (3Y-TZP) was explored with the objective of providing defined linear patterns capable of guiding bone-cell response.

METHODS

A nanosecond (ns-) laser was employed to fabricate microgrooves on the surface of 3Y-TZP discs, yielding three different groove periodicities (i.e., 30, 50 and 100 µm). The resulting topography and surface damage were characterized by confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM). X-Ray diffraction (XRD) and Raman spectroscopy techniques were employed to assess the hydrothermal degradation resistance of the modified topographies. Preliminary biological studies were conducted to evaluate adhesion (6 h) of human mesenchymal stem cells (hMSC) to the patterns in terms of cell number and morphology. Finally, Staphylococcus aureus adhesion (4 h) to the microgrooves was investigated.

RESULTS

The surface analysis showed grooves of approximately 1.8 µm height that exhibited surface damage in the form of pile-up at the edge of the microgrooves, microcracks and cavities. Accelerated aging tests revealed a slight decrease of the hydrothermal degradation resistance after laser patterning, and the Raman mapping showed the presence of monoclinic phase heterogeneously distributed along the patterned surfaces. An increase of the hMSC area was identified on all the microgrooved surfaces, although only the 50 µm periodicity, which is closer to the cell size, significantly favored cell elongation and alignment along the grooves. A decrease in Staphylococcus aureus adhesion was observed on the investigated micropatterns.

SIGNIFICANCE

The study suggests that linear microgrooves of 50 µm periodicity may help in promoting hMSC adhesion and alignment, while reducing bacterial cell attachment.

Antibacterial activity and biocompatibility of silver coating via aerosol deposition on titanium and zirconia surfaces

PURPOSE

The purpose of this in vitro study was to investigate the antibacterial effect and biocompatibility of silver coatings via aerosol deposition on titanium and zirconia surfaces.

METHODS

The surfaces of titanium and zirconia specimens were polished and coated with silver via aerosol deposition. After silver coating, the elemental composition, surface roughness and amount of silver released from the coated surfaces were measured. The bacterial growth on the silver-coated surfaces was investigated via crystal violet assay after incubation with Streptococcus gordonii for 24 h, Fusobacterium nucleatum for 72 h and Porphyromonas gingivalis for 48 h. Human gingival fibroblasts and mouse preosteoblasts were also cultured on the silver-coated specimens to examine the biocompatibility of the coating.

RESULTS

After silver coating via aerosol deposition, the surface roughness increased significantly, and the released silver ranged from 0.067 to 0.110 ppm. The tested bacteria formed significantly less biofilm on the silver-coated titanium surfaces than on the uncoated titanium surfaces. In contrast, biofilm formation on the silver-coated zirconia surfaces was greater than that on the uncoated zirconia surfaces. Human gingival fibroblasts and mouse preosteoblasts proliferated on the silver-coated surfaces without significant differences from the uncoated surfaces.

CONCLUSIONS

Silver coating via aerosol deposition provided an antibacterial effect against oral bacteria on titanium surfaces, whereas it promoted more bacterial growth on zirconia surfaces. The proliferation of fibroblasts and osteoblasts was not significantly affected by the silver coating on both titanium and zirconia surfaces.

Rose Petal Mimetic Surfaces with Antibacterial Properties Produced Using Nanoimprint Lithography

In this study, we produced bioinspired micro/nanotopography on the surface of poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) films and demonstrated that these films display antibacterial properties. In the first step, structures that are found on the surface of a rose petal were copied on the surface of PVDF-HFP films. Following this, a hydrothermal method was used to grow ZnO nanostructures on top of this rose petal mimetic surface. The antibacterial behavior of the fabricated sample was demonstrated against Gram-positive Streptococcus agalactiae (S. agalactiae) and Gram-negative Escherichia coli (E. coli) as model bacteria. For comparison purposes, the antibacterial behavior of a neat PVDF-HFP film was also investigated against both bacterial species. The results show that the presence of rose petal mimetic structures on PVDF-HFP helped the material to display improved antibacterial performance against both S. agalactiae and E. coli compared to the antibacterial performance of neat PVDF-HFP. The antibacterial performance was further enhanced for samples that had both rose petal mimetic topography and ZnO nanostructures on the surface.

A review: strategies to reduce infection in tantalum and its derivative applied to implants

Implant-associated infection is the main reasons for implant failure. Titanium and titanium alloy are currently the most widely used implant materials. However, they have limited antibacterial performance. Therefore, enhancing the antibacterial ability of implants by surface modification technology has become a trend of research. Tantalum is a potential implant coating material with good biological properties. With the development of surface modification technology, tantalum coating becomes more functional through improvement. In addition to improving osseointegration, its antibacterial performance has also become the focus of attention. In this review, we provide an overview of the latest strategies to improve tantalum antibacterial properties. We demonstrate the potential of the clinical application of tantalum in reducing implant infections by stressing its advantageous properties.

The effect of surface material, roughness and wettability on the adhesion and proliferation of Streptococcus gordonii, Fusobacterium nucleatum and Porphyromonas gingivalis

Background/purpose

Dental implants are inevitably exposed to bacteria in oral cavity. Understanding the colonization of bacteria on implant surface is necessary to prevent bacteria-related inflammation surrounding dental implants. The purpose of this study was to investigate the effect of surface properties on biofilm formation on the implant surface.

Materials and methods

One early colonizer, Streptococcus gordonii (S. gordonii), and two late colonizers, Fusobacterium nucleatum (F. nucleatum) and Porphyromonas gingivalis (P. gingivalis), were grown on the titanium and zirconia surfaces with two types of surface roughness for 24 and 72 h. Each bacterial biofilm on specimens was quantified using crystal violet assay and observed by scanning electron microscopy.

Results

S. gordonii formed more biofilm on the titanium surface than zirconia at the same roughness and more biofilm on the rough surface than smooth one of the same materials at 24 and 72 h of incubation. F. nucleatum adhered on all the surfaces at 24 h and proliferated actively on the surfaces except smooth zirconia at 72 h. P. gingivalis proliferated vigorously on the surfaces at 72 h while it scarcely adhered at 24 h. There was no consistent correlation between contact angle and biofilm formation of the three bacteria.

Conclusion

The three bacteria proliferated most on the rough titanium surface and least on the smooth zirconia surface. In addition, the proliferation was affected by the bacterial species as well as the surface properties.

Enhancing antibacterial property of porous titanium surfaces with silver nanoparticles coatings via electron-beam evaporation

Antibacterial activity is one of the most vital characteristics for Titanium (Ti) dental implants. Coating antibacterial material onto Ti surfaces is an effective approach to enhance their intrinsic antibacterial ability. However, a cost-effective but efficient coating strategy for realizing this objective still remains challenging. In this study, we proposed a novel implant surface modification strategy for coating silver nanoparticles onto the porous Ti surface via a facile electron beam evaporation (EBE) approach. Porous Ti surfaces were firstly prepared by sand-blasting large grit acid-etching (SLA) process. Then, the silver nanoparticles coating thickness on the porous Ti surface was adjusted and optimized by altering the duration of EBE process. Consequently, composite porous Ti surfaces with different silver thicknesses were synthesized. Polished Ti (PT) surface without SLA or EBE process was also prepared as the controlled blank group. The surface characterizations were analyzed by SEM, AFM, and XPS. After that, the antibacterial properties of all groups were tested with bacteria counting method, bacterial viability test, live/dead bacterial staining, and SEM examination. Results show that silver nanoparticles were uniformly distributed on the porous Ti surfaces after the SLA and EBE processes. After being incorporated with silver nanoparticles, the composite surfaces successfully inhibited the growth of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). The antibacterial ratio (AR) values of SLA-Ag groups increased with the increasing silver thickness and are significantly higher than those of PT and SLA groups. Therefore, by the SLA and EBE processes, the composite porous Ti surfaces modified with silver nanoparticles coatings demonstrate superior antibacterial property compared with pure Ti surfaces, which is highly promising for enhancing the antibacterial functions of dental implants. Graphical abstract.

Three interfaces of the dental implant system and their clinical effects on hard and soft tissues

Anatomically, the human tooth has structures both embedded within and forming part of the exterior surface of the human body. When a tooth is lost, it is often replaced by a dental implant, to facilitate the chewing of food and for esthetic purposes. For successful substitution of the lost tooth, hard tissue should be integrated into the implant surface. The microtopography and chemistry of the implant surface have been explored with the aim of enhancing osseointegration. Additionally, clinical implant success is dependent on ensuring that a barrier, comprising strong gingival attachment to an abutment, does not allow the infiltration of oral bacteria into the bone-integrated surface. Epithelial and connective tissue cells respond to the abutment surface, depending on its surface characteristics and the materials from which it is made. In particular, the biomechanics of the implant-abutment connection structure (i.e., the biomechanics of the interface between implant and abutment surfaces, and the screw mechanics of the implant-abutment assembly) are critical for both the soft tissue seal and hard tissue integration. Herein, we discuss the clinical importance of these three interfaces: bone-implant, gingiva-abutment, and implant-abutment.

Environmental, Microbiological, and Immunological Features of Bacterial Biofilms Associated with Implanted Medical Devices

The spread of biofilms on medical implants represents one of the principal triggers of persistent and chronic infections in clinical settings, and it has been the subject of many studies in the past few years, with most of them focused on prosthetic joint infections. We review here recent works on biofilm formation and microbial colonization on a large variety of indwelling devices, ranging from heart valves and pacemakers to urological and breast implants and from biliary stents and endoscopic tubes to contact lenses and neurosurgical implants. We focus on bacterial abundance and distribution across different devices and body sites and on the role of environmental features, such as the presence of fluid flow and properties of the implant surface, as well as on the interplay between bacterial colonization and the response of the human immune system.

Effects of Dicationic Imidazolium-Based Ionic Liquid Coatings on Oral Osseointegration of Titanium Implants: A Biocompatibility Study in Multiple Rat Demographics

Dicationic imidazolium-based ionic liquids with amino acid anions, such as IonL-phenylalanine (IonL-Phe), have been proposed as a multifunctional coating for titanium (Ti) dental implants. However, there has been no evaluation of the biocompatibility of these Ti coatings in the oral environment. This study aims to evaluate the effects of IonL-Phe on early healing and osseointegration of Ti in multiple rat demographics. IonL-Phe-coated and uncoated Ti screws were implanted into four demographic groups of rats to represent biological variations that could affect healing: young males (YMs) and females (YFs), ovariectomized (OVXFs) females, and old males (OMs). Samples underwent histopathological and histomorphometric analysis to evaluate healing at 7 and 30 days around IonL-coated and uncoated Ti. The real-time quantitative polymerase chain reaction was also conducted at the 2- and 7-day YM groups to evaluate molecular dynamics of healing while the IonL-Phe was present on the surface. IonL-coated and uncoated implants demonstrated similar histological signs of healing, while coated samples’ differential gene expression of immunological and bone markers was compared with uncoated implants at 2 and 7 days in YMs. While YMs presented suitable osseointegration for both uncoated and IonL-Phe-coated groups, decreased success rate in other demographics resulted from lack of supporting bone in YFs and poor bone quality in OVXFs and OMs. Overall, it was found that IonL-coated samples had increased bone-to-implant contact across all demographic groups. IonL-Phe coating led to successful osseointegration across all animal demographics and presented the potential to prevent failures in scenarios known to be challenged by bacteria.

Superhydrophilic multifunctional nanotextured titanium dental implants: in vivo short and long-term response in a porcine model

Current clinical demand in dental implantology is for a multifunctional device with optimum mechanical properties, improved biocompatibility and bioactivity, and having differential interactions with cells and pathogenic agents. This would minimise bacterial infection, biofilm formation and modulate inflammation, leading to a fast and durable osseointegration. The present study intends to establish the multifunctional behaviour of surface modified titanium dental implants that are superhydrophilic, with unique micro-nano or nanoscale topographies, developed by a facile hydrothermal technique. Here, the short and long-term performances of these textured implants are tested in a split mouth design using a porcine model, in pre- and post-loaded states. Quantitative and qualitative analyses of the bone implant interphase are performed through μ-CT and histology. Parameters that evaluate bone mineral density, bone contact volume and bone implant contact reveal enhanced bone apposition with better long-term response for the nano and micro-nano textured surfaces, compared to the commercial microtextured implant. Concurrently, the nanoscale surface features on implants reduced bacterial attachment by nearly 90% in vivo, outperforming the commercial variant. This preclinical evaluation data thus reveal the superiority of nano/micro-nano textured designs for clinical application and substantiate their improved osseointegration and reduced bacterial adhesion, thus proposing a novel dental implant with multifunctional characteristics.

Impact of physical decontamination methods on zirconia implant surface and subsequent bacterial adhesion: An in-vitro study

Objective

To evaluate the effect of routinely used physical decontamination methods on the surface characteristics of zirconia implants and subsequent ability of bacteria to adhere in vitro.

Background

Physical decontamination methods commonly used in peri‐implantitis therapy and routine implant maintenance can potentially alter zirconia implant surfaces.

Methods

Acid‐etched zirconia discs were instrumented with titanium curette (TC), plastic curette, air abrasive device, ultrasonic scaler (US) with stainless steel tip. Following instrumentation, surface topography, and surface elemental composition was analyzed using 3D‐laser scanning microscopy and energy‐dispersive X‐ray spectroscopy, respectively. Subsequently, plaque biofilm was cultured on zirconia discs for 48 h and bacterial adhesion assessed using a turbidity test and scanning electron microscopy.

Results

A significant difference in surface roughness was observed between the US and control group (p < 0.05). The US and TC caused gray surface discolouration on zirconia discs due to deposition of metallic residue as confirmed by X‐ray spectroscopy. No significant difference in bacterial adhesion was noted among all treatment groups (p > 0.05).

Conclusion

TC and US with stainless steel tips should be used with caution due to deposition of metallic residue on the surface. Air abrasive devices and plastic curettes caused minimal surface alterations and are, therefore, safer for zirconia implant decontamination.

Ceramic Bearings Are Associated With a Significantly Reduced Revision Rate in Primary Hip Arthroplasty: An Analysis From the National Joint Registry for England, Wales, Northern Ireland, and the Isle of Man

BACKGROUND

Prosthetic joint infection (PJI) is a devastating complication. Studies have suggested reduction in PJI with the use of ceramic bearings.

METHODS

Adult patients who underwent total hip arthroplasty (THA) using an uncemented acetabular component with ceramic-on-ceramic (CoC), ceramic-on-polyethylene (CoP), or metal-on-polyethylene (MoP) bearing surfaces between 2002 and 2016 were extracted from the National Joint Registry for England, Wales, Northern Ireland, and the Isle of Man. A competing risk regression model to investigate predictors of each revision outcome was used. Time-to-event was determined by duration of implantation since primary surgery with competing risks being death or revision. The results were adjusted for age, gender, American Association of Anaesthesiologists grade, body mass index, surgical indication, intraoperative complications, and implant data.

RESULTS

In total, 456,457 THAs (228,786 MoP, 128,403 CoC, and 99,268 CoP) were identified. Multivariable modeling showed that the risk of revision for PJI was significantly lower with CoC (risk ratio 0.748, P < .001) and CoP (risk ratio 0.775, P < .001) compared to MoP. Significant reduction in risk of aseptic and all-cause revision was also seen. The significant protective effect of ceramic bearing was predominantly seen 2 years after implantation. Aseptic revision beyond 2 years reduced by 18.1% and 24.8% for CoC and CoP (P < .001), respectively. All-cause revision rate beyond 2 years reduced by 21.6% for CoC and 27.1% for CoP (P < .001) CONCLUSION: This study demonstrates an association between the use of ceramic as part of the bearing, with lower rates of revision for all causes, revision for infection, and revision for aseptic causes, supporting ceramic bearings in THA.

Construction and performance evaluation of a sustained release implant material polyetheretherketone with antibacterial properties

OBJECTIVE

This study aimed to construct a tightly binding antibiotic sustained release system on the polyetheretherketone (PEEK) surface and investigate the cellular activity and antibacterial properties of the new oral implant materials.

METHODS

Low-temperature argon plasma under certain parameters was used to prepare P-PEEK with nano-topology, and chemical deposition technology was adopted to form a polydopamine (PDA) coating on the PEEK surface to build a biological binding platform, PDA/P-PEEK. Subsequently, vancomycin gelatin nanoparticles (Van-GNPs) were prepared by two-step desolvation method. Finally, Van-GNPs were combined with PEEK implant material surface to form a new composite material, Van-GNPs/PEEK. scanning electron microscope (SEM), atomic force microscope (AFM), energy dispersive spectrometer (EDS), and contact angle tester were used to comprehensively characterize the materials. The in vitro release test of Van was performed by dynamic dialysis with ultraviolet spectrophotometer. The cell cytotoxicity and adhesion tests were studied by mouse embryonic osteoblasts. The antibacterial properties were evaluated by bacterial adhesion test, plate colony counting, and antimicrobial ring test with Staphylococcus aureus and Streptococcus mutans.

RESULTS

PEEK was treated with low-temperature argon plasma and attached to PDA to form a biological binding platform. The synthesized Van-GNPs were smooth, round, with uniform particle size distribution, and bound to PEEK to form a new composite material, which can release Van constantly. Cell experiments showed that Van-GNPs/PEEK had no cytotoxicity and had good interaction with osteoblasts. Bacterial experiments showed that surface conjugation with Van-GNPs could significantly improve the antibacterial performance of PEEK against S. aureus and S. mutans.

SIGNIFICANCE

This study demonstrated that Van-GNPs/PEEK have good cellular compatibility and autonomous antibacterial properties, which provide a theoretical basis for the wide application of PEEK in the field of stomatology.

Laser surface texturing of zirconia-based ceramics for dental applications: A review

Laser surface texturing is widely explored for modifying the surface topography of various materials and thereby tuning their optical, tribological, biological, and other surface properties. In dentistry, improved osseointegration has been observed with laser textured titanium dental implants in clinical trials. Due to several limitations of titanium materials, dental implants made of zirconia-based ceramics are now considered as one of the best alternatives. Laser surface texturing of zirconia dental implants is therefore attracting increasing attention. However, due to the brittle nature of zirconia, as well as the metastable tetragonal ZrO₂ phase, laser texturing in the case of zirconia is more challenging than in the case of titanium. Understanding these challenges requires different fields of expertise, including laser engineering, materials science, and dentistry. Even though much progress was made within each field of expertise, a comprehensive analysis of all the related factors is still missing. This review paper provides thus an overview of the common challenges and current status on the use of lasers for surface texturing of zirconia-based ceramics for dental applications, including texturing of zirconia implants for improving osseointegration, texturing of zirconia abutments for reducing peri-implant inflammation, and texturing of zirconia restorations for improving restoration retention by bonding.

Peri-implantitis is not periodontitis: Scientific discoveries shed light on microbiome-biomaterial interactions that may determine disease phenotype

Peri-implantitis is an immune-mediated biological complication that is attributed to bacterial biofilms on the implant surface. As both periodontitis and peri-implantitis have similar inflammatory phenotypes when assessed cross-sectionally, treatment protocols for peri-implantitis were modeled according to those used for periodontitis. However, lack of efficacy of antimicrobial treatments targeting periodontal pathogens coupled with recent discoveries from open-ended microbial investigation studies create a heightened need to revisit the pathogenesis of peri-implantitis compared with that of periodontitis. The tale of biofilm formation on intraoral solid surfaces begins with pellicle formation, which supports initial bacterial adhesion. The differences between implant- and tooth-bound biofilms appear as early as bacterial adhesion commences. The electrostatic forces and ionic bonding that drive initial bacterial adhesion are fundamentally different in the presence of titanium dioxide or other implant alloys vs mineralized organic hydroxyapatite, respectively. Moreover, the interaction between metal surfaces and the oral environment leads to the release of implant degradation products into the peri-implant sulcus, which exposes the microbiota to increased environmental stress and may alter immune responses to bacteria. Clinically, biofilms found in peri-implantitis are resistant to beta-lactam antibiotics, which are effective against periodontal communities even as monotherapies and demonstrate a composition different from that of biofilms found in periodontitis; these facts strongly suggest that a new model of peri-implant infection is required.

Use of Plasma Technologies for Antibacterial Surface Properties of Metals

Bacterial infections of medical devices present severe problems connected with long-term antibiotic treatment, implant failure, and high hospital costs. Therefore, there are enormous demands for innovative techniques which would improve the surface properties of implantable materials. Plasma technologies present one of the compelling ways to improve metal's antibacterial activity; plasma treatment can significantly alter metal surfaces' physicochemical properties, such as surface chemistry, roughness, wettability, surface charge, and crystallinity, which all play an important role in the biological response of medical materials. Herein, the most common plasma treatment techniques like plasma spraying, plasma immersion ion implantation, plasma vapor deposition, and plasma electrolytic oxidation as well as novel approaches based on gaseous plasma treatment of surfaces are gathered and presented. The latest results of different surface modification approaches and their influence on metals' antibacterial surface properties are presented and critically discussed. The mechanisms involved in bactericidal effects of plasma-treated surfaces are discussed and novel results of surface modification of metal materials by highly reactive oxygen plasma are presented.

Ceramic Coating in Cemented Primary Total Knee Arthroplasty is Not Associated With Decreased Risk of Revision due to Early Prosthetic Joint Infection

BACKGROUND

Prosthetic joint infection (PJI) is one of the most frequent and devastating causes of short-term revision total knee arthroplasty (TKA). In vitro evidence suggests ceramic surfaces demonstrate resistance to biofilm, but the clinical effect of bearing surface modifications on the risk of PJI remains unclear. This premier registry-based study examines the influence of ceramic bearing surface coatings on the outcome in cemented primary TKA.

METHODS

In total, 117,660 cemented primary TKAs in patients with primary osteoarthritis recorded in the German arthroplasty registry since 2012 were followed up for a maximum of 3 years. The primary endpoint was risk of revision for PJI on ceramic coated and uncoated cobalt-chromium-molybdenum femoral components. Propensity score matching for age, gender, obesity, diabetes mellitus, depression and Elixhauser comorbidity index, and substratification on common design twins with and without coating was performed.

RESULTS

In total, 4637 TKAs (85.1% female) with a ceramic-coated femoral component were identified, 42 had been revised for PJI and 122 for other reasons at 3 years. No survival advantage due to the risk of revision for PJI could be determined for ceramic-coated components. Revision for all other reasons demonstrated a significant higher rate for TKAs with ceramic-coated components. However, the results of this were confounded by a strong prevalence (20.7% vs 0.3%) of metal sensitivity in the ceramic-coated group.

CONCLUSION

No evidence of reduced risk for PJI due to ceramic-coated implants in cemented primary TKA was found. Further analysis for revision reasons other than PJI is required.

The effect of zirconia and titanium surfaces on biofilm formation and on host-derived immunological parameters

The aim of this study was to analyse the effect of zirconia and titanium surfaces on biofilm formation and host-derived parameters. Studies comparing zirconia and titanium surfaces were selected up to September 1, 2019. The outcome measures were surface roughness, contact angle, bacterial count, bacterial adherence, biofilm thickness, bacterial distribution, and specifically investigated biofilm and specific host-derived immunological parameters. Random-effects meta-analyses of in vitro and in vivo studies were conducted. A total of 39 studies were included for data extraction. In the systematic review data, 10 studies stated that zirconia accumulated less initial oral biofilm parameters, 16 investigations showed negligible inter-material differences, and only one study showed that zirconia attracted the most biofilm. However, in the meta-analysis, the bacterial coverage was found to be significantly superior for zirconia surfaces (P< 0.00001); the other outcome measures did not show any statistically significant differences between zirconia and titanium for the remaining parameters and the studies presented a substantial degree of heterogeneity. Overall, on the basis of the meta-analysis, the current data situation does not allow a clear preference for the use of zirconia or titanium.

Review of silicone surface modification techniques and coatings for antibacterial/antimicrobial applications to improve breast implant surfaces

Silicone implants are widely used in the medical field for plastic or reconstructive surgeries for the purpose of soft tissue issues. However, as with any implanted object, healthcare-associated infections are not completely avoidable. The material suffers from a lack of biocompatibility and is often subject to bacterial/microbial infections characterized by biofilm growth. Numerous strategies have been developed to either prevent, reduce, or fight bacterial adhesion by providing an antibacterial property. The present review summarizes the diverse approaches to deal with bacterial infections on silicone surfaces along with the different methods to activate/oxidize the surface before any surface modifications. It includes antibacterial coatings with antibiotics or nanoparticles, covalent attachment of active bacterial molecules like peptides or polymers. Regarding silicone surfaces, the activation step is essential to render the surface reactive for any further modifications using energy sources (plasma, UV, ozone) or chemicals (acid solutions, sol-gel strategies, chemical vapor deposition). Meanwhile, corresponding work on breast silicone prosthesis is discussed. The latter is currently in the line of sight for causing severe capsular contractures. Specifically, to that end, besides chemical modifications, the antibacterial effect can also be achieved by physical surface modifications by adjusting the surface roughness and topography for instance.

Mammalian cell response and bacterial adhesion on titanium healing abutments: effect of multiple implantation and sterilization cycles

OBJECTIVE

Multiple implantations of the implant healing abutment (IHA) could adversely impact its surface properties in vivo. Furthermore, the effect of sterilization and reuse of the IHA on soft tissue viability and bacterial contamination has not been extensively studied. The goal of this study was to perform an in vitro analysis of mammalian cell viability and bacterial adhesion on the surfaces of retrieved IHA after single and multiple implantations and repetitive cycles of sterilization.

MATERIALS AND METHODS

IHA surface morphology was studied using optical microscopy. Cell viability of gingival fibroblasts (HGF-1) and oral keratinocytes (HOKg) in indirect contact with IHAs was assessed for 3 and 7 days. Immersion in bacterial culture was performed with a polyculture of Streptococcus species for 3 days and Streptococcus species with Fusobacterium nucleatum for 7 days.

RESULTS

IHAs exhibited signs of surface damage even after a single exposure to the oral cavity. Fibroblasts did not show a significant preference towards control IHAs over used IHAs, whereas keratinocytes exhibited a significant decrease in viability when exposed to IHAs after multiple implantation cycles as compared with controls. Adherent bacterial count increased with increasing number of IHA implantations for both polycultures.

CONCLUSIONS

Reusing of IHAs in vivo promoted surface degradation in addition to adversely impacting host cell viability and oral bacterial attachment in vitro. These findings show IHA reuse might potentially affect its clinical performance.

CLINICAL RELEVANCE

Careful consideration should be taken when reusing IHAs in patients because this practice can result in permanent surface changes that might affect soft tissue integration during the healing period and promote bacterial colonization.

Effects of multiple implantations of titanium healing abutments: Surface characteristics and microbial colonization

OBJECTIVE

Very few studies have investigated dental implant components involved in the early stage of healing, especially the implant healing abutment (IHA), despite its vital role in soft tissue contouring and shaping after implant placement. Although these components are labelled by the manufacturer for "single-use only," it is a common clinical practice to clean, sterilize, and reuse them.

METHODS

In the present study, IHAs after single and multiple implantations were retrieved as per standard procedures, and biological material isolated from the surface was subjected to 16S rRNA sequence analysis. The microbiome analysis was followed by cleaning and sterilization in order to replicate clinical sterilization techniques. Following sterilization, retrievals were subjected to surface characterization with optical and scanning electron microscopy to investigate surface features, and electrochemical testing was performed to evaluate corrosion behavior.

RESULTS

The microbiota was comprised of early colonizers including Streptococcus species and secondary anaerobic colonizers such as Fusobacterium, Capnocytophaga, and Prevotella species. The surface analysis revealed that irrespective of the cleaning and sterilization techniques, the pristine, homogeneous surface of the new, unused IHAs could not be restored. Both single and multiple-use IHAs had severe surface changes including discoloration, major abrasions, biological contamination, and the IHA retrievals exhibited higher corrosion rate as compared to control specimens.

SIGNIFICANCE

Reusing IHAs multiple times may not be a prudent practice as the microbial colonization and surface changes caused by using this component multiple times may affect the performance of IHAs in soft tissue healing.

Vancomycin-loaded electrospun polycaprolactone/nano-hydroxyapatite membrane for the treatment of blood infections

Nowadays, because of the resistance of bacteria to antibiotics, researchers are trying to make new antibiotics or sometimes even bring them back into the treatment cycle so that they could eliminate the bacteria's resistance. On the other hand, the use of nanofibers has become widespread in many fields for their unique properties and convenient design. The present study focuses on the production of hydrophobic nanofibers to absorb the bacteria and their toxins from the bloodstream that contains the infection. Many bacterial surfaces have hydrophobic surfactant properties due to hydrophobic surface protein. According to the principle of binding two hydrophobic molecules to each other in an aqueous medium, the nanofibers are designed to physically absorb the bacteria. The use of antibiotics in the study can remove some unattached bacteria. In addition, using nanofiber manufacturing techniques can reduce the resistance of bacteria to antibiotics. The construction of the desired membrane can be used in subsequent studies as a replacement membrane for dialysis filters.

Quantitative Interpretation of Hydration Dynamics Enabled the Fabrication of a Zwitterionic Antifouling Surface

In the medical industry, zwitterionic brushes have received significant attention owing to their antifouling effect that arose from their hydration ability. However, sufficient understanding of the hydration dynamics of zwitterionic brushes is required to fabricate the precisely controlled antifouling medical devices. In this paper, we successfully show that hydration, the interaction between water molecules and zwitterionic brushes, and its dynamics can be evaluated logically and quantitatively using (i) water contact angle, (ii) molecular dynamics simulation, and (iii) Raman spectroscopy. Based on the intuitive results on hydration, we precisely optimized the antifouling property of the model medical device, a removable orthodontic retainer, with various grafting efficiencies of 2-methacryloyloxyethyl phosphate choline. As a result, the model device reduced nonspecific adsorption of proteins and bacteria, indicating an improved antifouling effect, and also inhibited the formation of a biofilm. Furthermore, the device showed excellent physical properties desirable for application in the orthodontic field, meaning the balance between the antibacterial property and mechanical strength.

Biological Responses to the Transitional Area of Dental Implants: Material- and Structure-Dependent Responses of Peri-Implant Tissue to Abutments

The stability of peri-implant tissue is essential for the long-term success of dental implants. Although various types of implant connections are used, little is known about the effects of the physical mechanisms of dental implants on the stability of peri-implant tissue. This review summarizes the relevant literature to establish guidelines regarding the effects of connection type between abutments and implants in soft and hard tissues. Soft tissue seals can affect soft tissue around implants. In external connections, micromobility between the abutment and the hex component of the implant, resulting from machining tolerance, can destroy the soft tissue seal, potentially leading to microbial invasion. Internal friction connection implants induce strain on the surrounding bone via implant wall expansion that translates into masticatory force. This strain is advantageous because it increases the amount and quality of peri-implant bone. The comparison of internal and external connections, the two most commonly used connection types, reveals that internal friction has a positive influence on both soft and hard tissues.

Bioactive Glass Applications in Dentistry

At present, researchers in the field of biomaterials are focusing on the oral hard and soft tissue engineering with bioactive ingredients by activating body immune cells or different proteins of the body. By doing this natural ground substance, tissue component and long-lasting tissues grow. One of the current biomaterials is known as bioactive glass (BAG). The bioactive properties make BAG applicable to several clinical applications involving the regeneration of hard tissues in medicine and dentistry. In dentistry, its uses include dental restorative materials, mineralizing agents, as a coating material for dental implants, pulp capping, root canal treatment, and air-abrasion, and in medicine it has its applications from orthopedics to soft-tissue restoration. This review aims to provide an overview of promising and current uses of bioactive glasses in dentistry.

Pyrosequencing of the subgingival microbiome in peri-implantitis after non-surgical mechanical debridement therapy

BACKGROUND AND OBJECTIVES

Peri-implantitis remains a challenge for dental implant therapy, and the prognosis of non-surgical therapy for peri-implantitis is unsatisfactory. In order to reveal the impact of non-surgical mechanical debridement therapy on microbial communities, we investigated the subgingival microbial communities of healthy implants and implants with peri-implantitis, both before and after the therapy.

MATERIAL AND METHODS

Subgingival plaques were collected from patients with healthy dental implants (HC; n = 10) and from patients with peri-implantitis (n = 13) before and after non-surgical mechanical debridement therapy. The treatment was conducted using curettes for submucosal debridement followed by irrigation with 0.2% (w/v) chlorhexidine, with re-examination 1 month later. 16S rRNA pyrosequencing was used to analyze the subgingival microbiome, and co-occurrence networks were adopted to explore the interactions between pathogens in the microbial communities.

RESULTS

A total of 506 955 high-quality reads were generated, and 2222 operational taxonomic units were finally detected using a 97% similarity cutoff, with a mean of 249 ± 69 per sample. The peri-implantitis sites harbored similar microbial communities before and after the treatment, as demonstrated by the microbial diversity, relative abundance, and prevalence of bacteria. Most importantly, the microbial community structures were stable before and after non-surgical therapy based on the microbial diversity and bacterial composition, as well as the interactions between key pathogens, including Enterobacteriaceae, Selenomonas sputigena, Parvimonas, Eubacterium infirmum, Campylobacter gracilis, Tannerella forsythia, and Fusobacterium, which were measured using a co-occurrence network analysis. Periodontal pathogens were also detected in subgingival plaque after the treatment. Distinct microbial communities were found between the healthy and peri-implantitis sites.

CONCLUSION

Our results demonstrate that non-surgical mechanical debridement therapy did not significantly affect the subgingival microbial communities in peri-implantitis, and the stable microbial networks created via interactions among pathogens may be responsible for the poor prognosis of peri-implantitis treatment.

Surface changes and bacterial adhesion on implant abutment materials after various clinical cleaning procedures

BACKGROUND

Supportive treatments are essential to long-term dental implant success; however, professional cleaning procedures may alter the surfaces of implant abutments and lead to adverse biological responses. This study aimed to evaluate four clinically used cleaning procedures by examining surface changes and subsequent bacterial adhesion on abutment materials.

METHODS

Discs of titanium and zirconia were polished and divided into five groups: titanium curette treatment, carbon fiber reinforced plastic curette treatment, ultrasonic scaling with carbon fiber tip treatment, air polishing with glycine powder, and control group without any treatment. After instrumentation, the arithmetical mean roughness (Ra), hydrophilicity, and surface free energy were recorded. The bacterial adhesion was evaluated after 1 h of Streptococcus mitis incubation by optical microscope and quantified by turbidity test.

RESULTS

Among the titanium samples, titanium curette treatment group showed significant surface morphology changes, increased Ra, hydrophilicity, surface free energy, and higher optical density of adhered bacteria. As for the zirconia samples, the differences in surface morphology, Ra, and bacterial adhesion between groups were nonsignificant.

CONCLUSION

Comparing to titanium, zirconia was less susceptible to surface changes after tested cleaning procedures. Titanium curette should be used with care on titanium abutments.

In Vitro Evaluation of Bacterial Adhesion and Bacterial Viability of Streptococcus mutans, Streptococcus sanguinis, and Porphyromonas gingivalis on the Abutment Surface of Titanium and Zirconium Dental Implants

Objective

To evaluate the in vitro adherence and viability of 3 bacterial species Streptococcus mutans (ATCC 25175), Streptococcus sanguinis (ATCC 10556), and Porphyromonas gingivalis (ATCC 33277) on the surfaces of dental implants of titanium, zirconium, and their respective fixing screws.

Methods

Two analysis groups were formed: group 1 with 3 titanium pillars and group 2 with 3 zirconium pillars, each with their respective fixing screws. Each of these groups was included in tubes with bacterial cultures of Streptococcus mutans (ATCC 25175), Streptococcus sanguinis (ATCC 10556), and Porphyromonas gingivalis (ATCC 33277). These samples were incubated at 37°C under anaerobic conditions. Bacterial adherence was assessed by measurement of the change in colony-forming units (CFU), and bacterial viability was evaluated with the colorimetric test of 3-(4,5-dimethylthiazol-2)-2,5 diphenyl tetrazolium bromide (MTT).

Results

The bacterial adhesion in the titanium abutments was higher for Streptococcus mutans (190.90 CFU/mL), and the viability was greater in Porphyromonas gingivalis (73.22%). The zirconium abutment group showed the highest adherence with Streptococcus mutans (331.82 CFU/mL) and the highest bacterial viability with the S. sanguinis strain (38.42%). The titanium fixation screws showed the highest adhesion with S. sanguinis (132.5 CFU/mL) compared to the zirconium fixation screws where S. mutans had the highest adhesion (145.5 CFU/mL). The bacterial viability of S. mutans was greater both in the titanium fixation screws and in the zirconium fixation screws 78.04% and 57.38%, respectively.

Conclusions

Our results indicate that there is in vitro bacterial adherence and viability in both titanium abutments and zirconium abutments and fixation screws for both. Streptococcus mutans is the microorganism that shows the greatest adherence to the surfaces of both titanium and zirconium and the fixing screws of the latter. On the contrary, bacterial viability is greater on the titanium abutments with P. gingivalis than on the zirconium abutments with S. sanguinis. With respect to the fixation screws, in both cases, the viability of S. mutans was greater with respect to the other bacteria. In general, the titanium abutments showed less adherence but greater bacterial viability.

Real-Time Imaging of Bacteria/Osteoblast Dynamic Coculture on Bone Implant Material in an in Vitro Postoperative Contamination Model

Biomedical implants are an important part of evolving modern medicine but have a potential drawback in the form of postoperative pathogenic infection. Accordingly, the "race for surface" combat between invasive bacteria and host cells determines the fate of implants. Hence, proper in vitro systems are required to assess effective strategies to avoid infection. In this study, we developed a real time observation model, mimicking postoperative contamination, designed to follow E. coli proliferation on a titanium surface occupied by human osteoblastic progenitor cells (STRO). This model allowed us to monitor E. coli invasion of human cells on titanium surfaces coated and uncoated with fibronectin. We showed that the surface colonization of bacteria is significantly enhanced on fibronectin coated surfaces irrespective of whether areas were uncovered or covered with human cells. We further revealed that bacterial colonization of the titanium surfaces is enhanced in coculture with STRO cells. Finally, this coculture system provides a comprehensive system to describe in vitro and in situ bacterial and human cells and their localization but also to target biological mechanisms involved in adhesion as well as in interactions with surfaces, thanks to fluorescent labeling. This system is thus an efficient method for studies related to the design and function of new biomaterials.

Prevalence of Peri-Implantitis in Implants with Turned and Rough Surfaces: a Systematic Review

Objectives

Moderately-rough implant surface may improve implant therapy in terms of bone integration, but the increased surface roughness might affect the initiation and development of peri-implantitis. The aim of the present review was to compare the prevalence of peri-implantitis in implants with rough and turned (machined) implant surfaces.

Material and Methods

An electronic literature search was conducted of the MEDLINE and EMBASE databases for articles published between 1 January 1990 and 1 March 2018. Clinical human studies in the English language that had reported on prevalence of peri-implantitis in tuned and rough surface implants were searched. The initial search resulted in 690 articles.

Results

Eight articles with 2992 implants were included in the systematic review. The incidence of peri-implantitis for two implant surfaces varied between studies. A meta-analysis was not feasible due to the heterogeneity among studies. Implant with rough surfaces were more favourable for plaque accumulation during short-term follow-up. On a long-term, turned implants surfaces were associated with more plaque and higher peri-implant bone loss. Peri-implant clinical parameters and survival rate for two implant surfaces was similar.

Conclusions

Within the limitations of the present study, rough implant surface does not seem to increase the incidence of peri-implantitis in comparison to turned implants surface.

The role of bacterial biofilm and mechanical forces in modulating dental implant failures

Currently many assume that bacteria are the primary etiological factor associated with failure of titanium dental implants. However, emerging data indicates a possible role for mechanical forces in implant failure. This study is based on the hypothesis that the synergistic effect of mechanical forces and bacterial biofilm can lead to surface damage resulting in in vivo release of metallic particles. The primary aim of the study was to develop a dynamic fatigue test method for dental implants immersed in wet environments such as; (i) 0.01 M phosphate buffer saline (PBS); (ii) lactic acid (pH = 5); (iii) bacterial polyculture. Four dental implants each were subjected to fatigue loading from 45 N to 450 N at 4 Hz for 2 million cycles while immersed in (i) PBS (negative control); (ii) bacterial culture (test); and (iii) lactic acid (positive control). Post-testing, optical microscopy, x-ray photoelectron spectroscopy, and electrochemical corrosion tests were performed to evaluate the surface morphology, chemistry, and potential, respectively, of titanium implants. Post-testing, surface discoloration was evident in all three groups. However, the surface damage was further established in XPS analyses of test specimens, which showed that the interplay of bacterial biofilm and mechanical forces resulted in thinning of the TiO₂. Lower corrosion potential (Ecorr) of the test specimens compared to positive and negative controls also illustrated damage to the oxide layer. However, other electrochemical parameters such as linear polarization resistance (LPR) and corrosion rate (CR) were comparable among the groups indicating the corrosion resistance post-testing. The synergistic effect of cyclic occlusal loading and bacteria biofilm could negatively affect the surface of titanium dental implants.

Effects of thermal treatment on the adhesion strength and osteoinductive activity of single-layer graphene sheets on titanium substrates

In recent years, dental implants have become the preferred approach for the restoration of missing teeth. At present, most dental implants are made of pure titanium, and are affected by peri-implantitis and bone resorption, which usually start from the implant neck, due to the complex environment in this region. To address these issues, in this study we modified the surface of titanium (Ti) implants to exploit the antibacterial and osteoinductive effects of single-layer graphene sheets. Chemical vapor deposition (CVD)-grown single-layer graphene sheets were transferred to titanium discs, and a method for improving the adhesion strength of graphene on Ti was developed due to compromised adhesion strength between graphene and titanium surface. A thermal treatment of 2 h at 160 °C was found to enhance the adhesion strength of graphene on Ti to facilitate clinical transformation. Graphene coatings of Ti enhanced cell adhesion and osteogenic differentiation, and imparted antibacterial activity to Ti substrate; these favorable effects were not affected by the thermal treatment. In summary, the present study elucidated the effects of a thermal treatment on the adhesion strength and osteoinductive activity of single-layer graphene sheets on titanium substrates.

Current therapies in treatment and prevention of fracture wound biofilms: why a multifaceted approach is essential for resolving persistent infections

Traumatic orthopedic injuries, particularly extremity wounds, are a significant cause of morbidity. Despite prophylactic antibiotic treatment and surgical intervention, persistent infectious complications can and do occur. Persistent bacterial infections are often caused by biofilms, communities of antibiotic tolerant bacteria encased within a matrix. The structural and metabolic differences in this mode of growth make treatment difficult. Herein, we describe both established and novel, experimental treatments targeted at various stages of wound healing that are specifically aimed at reducing and eliminating biofilm bacteria. Importantly, the highly tolerant nature of these bacterial communities suggests that most singular approaches could be circumvented and a multifaceted, combinatorial approach will be the most effective strategy for treating these complicated infections.

The effect of bearing surface on risk of periprosthetic joint infection in total hip arthroplasty: a systematic review and meta-analysis

AIMS

Periprosthetic joint infection (PJI) is a serious complication of total hip arthroplasty (THA). Different bearing surface materials have different surface properties and it has been suggested that the choice of bearing surface may influence the risk of PJI after THA. The objective of this meta-analysis was to compare the rate of PJI between metal-on-polyethylene (MoP), ceramic-on-polyethylene (CoP), and ceramic-on-ceramic (CoC) bearings.

PATIENTS AND METHODS

Electronic databases (Medline, Embase, Cochrane library, Web of Science, and Cumulative Index of Nursing and Allied Health Literature) were searched for comparative randomized and observational studies that reported the incidence of PJI for different bearing surfaces. Two investigators independently reviewed studies for eligibility, evaluated risk of bias, and performed data extraction. Meta-analysis was performed using the Mantel-Haenzel method and random-effects model in accordance with methods of the Cochrane group.

RESULTS

Our search strategy revealed 2272 studies, of which 17 met the inclusion criteria and were analyzed. These comprised 11 randomized controlled trials and six observational studies. The overall quality of included studies was high but the observational studies were at high risk of bias due to inadequate adjustment for confounding factors. The overall cumulative incidence of PJI across all studies was 0.78% (1514/193 378). For each bearing combination, the overall incidence was as follows: MoP 0.85% (1353/158 430); CoP 0.38% (67/17 489); and CoC 0.53% (94/17 459). The meta-analysis showed no significant difference between the three bearing combinations in terms of risk of PJI.

CONCLUSION

On the basis of the clinical studies available, there is no evidence that bearing choice influences the risk of PJI. Future research, including basic science studies and large, adequately controlled registry studies, may be helpful in determining whether implant materials play a role in determining the risk of PJI following arthroplasty surgery. Cite this article: Bone Joint J 2018;100-B:134-42.

Mechanisms of the enhanced antibacterial effect of Ag-TiO2 coatings

It has been demonstrated that Ag-TiO₂ nanocomposite coatings with excellent antimicrobial activity and biocompatibility have the potential to reduce infection problems. However, the mechanism of the synergistic effect of Ag-TiO₂ coatings on antibacterial efficiency is still not well understood. In this study, five types of Ag-TiO₂ nanocomposited coatings with different TiO₂ contents were prepared on a titanium substratum. Leaching tests indicated that the incorporation of TiO₂ nanoparticles into an Ag matrix significantly promoted Ag ion release. Surface energy measurements showed that the addition of TiO₂ nanoparticles also significantly increased the electron donor surface energy of the coatings. Bacterial adhesion assays with Escherichia coli and Staphylococcus aureus demonstrated that the number of adhered bacteria decreased with increasing electron donor surface energy. The increased Ag ion release rate and the increased electron donor surface energy contributed to an enhanced antibacterial efficiency of the coatings.

Chitosan coating as an antibacterial surface for biomedical applications

Background and objectives

A current public health issue is preventing post-surgical complications by designing antibacterial implants. To achieve this goal, in this study we evaluated the antibacterial activity of an animal-free chitosan grafted onto a titanium alloy.

Methods

Animal-free chitosan binding on the substrate was performed by covalent link via a two-step process using TriEthoxySilylPropyl Succinic Anhydride (TESPSA) as the coupling agent. All grafting steps were studied and validated by means of X-ray Photoelectron Spectroscopy (XPS), Time-of-Flight secondary ion mass spectrometry (ToF-SIMS) analyses and Dynamic-mode Secondary Ion Mass Spectrometry (DSIMS). The antibacterial activity against Escherichia coli and Staphylococcus aureus strains of the developed coating was assessed using the number of colony forming units (CFU).

Results

XPS showed a significant increase in the C and N atomic percentages assigned to the presence of chitosan. A thick layer of polymer deposit was detected by ToF-SIMS and the results obtained by DSIMS measurements are in agreement with ToF-SIMS and XPS analyses and confirms that the coating synthesis was a success. The developed coating was active against both gram negative and gram positive tested bacteria.

Conclusion

The success of the chitosan immobilization was proven using the surface characterization techniques applied in this study. The coating was found to be effective against Escherichia coli and Staphylococcus aureus strains.

Position paper for the evaluation and management of oral status in patients with valvular disease: Groupe de Travail Valvulopathies de la Société Française de Cardiologie, Société Française de Chirurgie Orale, Société Française de Parodontologie et d'Implantologie Orale, Société Française d'Endodontie et Société de Pathologie Infectieuse de Langue Française

Oral health is of particular importance in patients with heart valve diseases because of the risk of infective endocarditis. Recommendations for antibiotic prophylaxis before dental procedures have been restricted, but the modalities of oral evaluation and dental care are not detailed in guidelines. Therefore, a multidisciplinary working group reviewed the literature to propose detailed approaches for the evaluation and management of buccodental status in patients with valvular disease. Simple questions asked by a non-dental specialist may draw attention to buccodental diseases. Besides clinical examination, recent imaging techniques are highly sensitive for the detection of inflammatory bone destruction directly related to oral or dental infection foci. The management of buccodental disease before cardiac valvular surgery should be adapted to the timing of the intervention. Simple therapeutic principles can be applied even before urgent intervention. Restorative dentistry and endodontic and periodontal therapy can be performed before elective valvular intervention and during the follow-up of patients at high risk of endocarditis. The detection and treatment of buccodental foci of infection should follow specific rules in patients who present with acute endocarditis. Implant placement is no longer contraindicated in patients at intermediate risk of endocarditis, and can also be performed in selected high-risk patients. The decision for implant placement should follow an analysis of general and local factors increasing the risk of implant failure. The surgical and prosthetic procedures should be performed in optimal safety conditions. It is therefore now possible to safely decrease the number of contraindicated dental procedures in patients at risk of endocarditis.

[Current dental implant design and its clinical importance]

The development of clinical implant dentistry was intensively affected by dental implant design improvement and innovation, which brought about new concept, even milestone-like changes of clinical protocol. The current improvements of dental implant design and their clinical importance could be highlighted as followings: 1) The implant apical design influences the implant preliminary stability in immediate implant. The apical 3-5 mm design of implant makes implant stable in immediate implant, because this part would be screwed into alveolar bone through fresh socket, the other part of implant could not be tightly screwed in the socket because of smaller implant diameter. Implant apical form, screw design, self-taping of apical part would be essential for immediate implant. 2) The enough preliminary stability of implant makes immediate prosthesis possible. When osseointegration does not occur, the implant stability comes from a mechanical anchorage, which depends on implant form, screw thread and self-taping design. 3) Implant neck design may have influence for soft tissue recession in esthetic zone. The implant with large shoulder would not be selected for the esthetic area. The platform design may be more favorable in the area. 4) The connection design between implant and abutment is thought a very important structure in implant long-term stability. Moose taper and "tube in tube" were well documented structure design in 20-year clinical practice in Peking University. 5) In last 15 years, the plenty studies showed the platform design of implant had positive influence in implant marginal bone level. Whatever in single implant restoration or multi-implant prosthesis. 6) The digital technology makes clinical work more precise and high-tech. This would be a trend in implant dentistry. New generation of chair-side digital computer-aided design/computer-aided manufacturing makes immediate prosthesis without conventional impression possible. 7) New abutment design have changed clinical protocol greatly. The All-on-four concept and Weldone concept benefit both from the abutment innovation, which were large angulated abutment and special welding abutment materials.

TiO2 nanorod arrays as a photocatalytic coating enhanced antifungal and antibacterial efficiency of Ti substrates

Aim: To investigate the photocatalytic inactivation of fungi and bacteria mediated by TiO2 nanorod arrays (TNRs). Materials & methods: The features of TNRs were characterized by scanning electron microscopy, atomic force microscopy, transmission electron microscopy, x-ray diffraction (XRD) and contact angle measurement. The antimicrobial efficiency was detected on biofilm and planktonic forms of Candida albicans, Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis by crystal violet and XTT (2,3-bis [2-methoxy-4-nitro-5-sulfophenyl]-2H-tetrazolium-5-caboxanilide) assay, confocal laser scanning microscope and colony-forming assay. Fluorogenic quantitative assay was used to explore the underlying mechanism. Results & conclusion: TNRs were well aligned and vertically oriented on Ti with a diameter of about 100 μm, possessing a rougher surface and better hydrophilicity. Moreover, TNRs exhibited significantly higher antifungal and antibacterial efficiency compared with Ti under UV irradiation, laying the foundation for surface modification of implants with TNRs.

Differential Adhesive and Bioactive Properties of the Polymeric Surface Coated with Graphene Oxide Thin Film

Surface engineering of implantable devices involving polymeric biomaterials has become an essential aspect for medical implants. A surface enhancement technique can provide an array of unique surface properties that improve its biocompatibility and functionality as an implant. Polyurethane-based implants that have found extensively acclaimed usage as an implant in biomedical applications, especially in the area of cardiovascular devices, still lack any mechanism to ward off bacterial or platelet adhesion. To bring out such a defense mechanism we are proposing a surface modification technique. Graphene oxide (GO) in very thin film form was wrapped onto the electrospun fibroporous polycarbonate urethane (PCU) membrane (GOPCU) by a simple method of electrospraying. In the present study, we have developed a simple single-step method for coating a polymeric substrate with a thin GO film and evaluated the novel antiadhesive activity of these films. SEM micrographs after coating showed the presence of very thin GO films over the PCU membrane. On the GOPCU surface, the contact angle was shifted by ∼30°, making the hydrophobic PCU surface slightly hydrophilic, while Raman spectral characterization and mapping showed the presence and distribution of GO over 75% of the membrane. A reduced platelet adhesion on the GOPCU surface was observed; meanwhile, bacterial adhesion also got reduced by 85% for Staphylococcus aureus (Gram positive, cocci) and 64% for Pseudomonas aeruginosa (Gram negative, bacilli). A cell adhesion study conducted using mammalian fibroblast cells projected its proliferation percentage in a MTT assay, with 82% cell survival on PCU and 86% on GOPCU after 24 h culture, while a study for an extended period of 72 h showed 87% of survival on PCU and 88% on GOPCU. This plethora of functionalities by a simple modification technique makes thin GO films a self-sufficient surface engineering material for future biomedical applications.

Histatin peptides: Pharmacological functions and their applications in dentistry

There are many human oral antimicrobial peptides responsible for playing important roles including maintenance, repairing of oral tissues (hard or soft) and defense against oral microbes. In this review we have highlighted the biochemistry, physiology and proteomics of human oral histatin peptides, secreted from parotid and submandibular salivary glands in human. The significance of these peptides includes capability for ionic binding that can kill fungal Candida albicans. They have histidine rich amino acid sequences (7-12 family members; corresponding to residues 12-24, 13-24, 12-25, 13-25, 5-11, and 5-12, respectively) for Histatin-3. However, Histatin-3 can be synthesized proteolytically from histatin 5 or 6. Due to their fungicidal response and high biocompatibility (little or no toxicity), these peptides can be considered as therapeutic agents with most probable applications for example, artificial saliva for denture wearers and salivary gland dysfunction conditions. The objectives of current article are to explore the human histatin peptides for its types, chemical and biological aspects. In addition, the potential for therapeutic bio-dental applications has been elaborated.

The Relationship of Bacterial Biofilms and Capsular Contracture in Breast Implants

Capsular contracture is a common sequelae of implant-based breast augmentation. Despite its prevalence, the etiology of capsular contracture remains controversial. Numerous studies have identified microbial biofilms on various implantable materials, including breast implants. Furthermore, biofilms have been implicated in subclinical infections associated with other surgical implants. In this review, we discuss microbial biofilms as a potential etiology of capsular contracture. The review also outlines the key diagnostic modalities available to identify the possible infectious agents found in biofilm, as well as available preventative and treatment measures.

Evaluation of mammalian and bacterial cell activity on titanium surface coated with dicationic imidazolium-based ionic liquids

This work presents a new strategy to protect titanium surfaces against bacterial colonization and biofilm formation using dicationic imidazolium-based ionic liquid coatings.

Spectroscopic and microscopic investigation of the effects of bacteria on dental implant surfaces

The surface morphology and chemical composition of commercially pure titanium dental implants and healing abutments exposed in vitro or in vivo to oral bacteria were studied.