Electrolyzed Saline Targets Biofilm Periodontal Pathogens In Vitro.

Preventing the development and recurrence of periodontal diseases often includes antimicrobial mouthrinses to control the growth of the periodontal pathogens. Most antimicrobials are nonselective, targeting the symbiotic oral species as well as the dysbiosis-inducing ones. This affects the overall microbial composition and metabolic activity and consequently the host-microbe interactions, which can be detrimental (associated with inflammation) or beneficial (health-associated). Consequently, guiding the antimicrobial effect for modulating the microbial composition to a health-associated one should be considered. For such an approach, this study investigated electrolyzed saline as a novel rinse. Electrolyzed saline was prepared from sterile saline using a portable electrolysis device. Multispecies oral homeostatic and dysbiotic biofilms were grown on hydroxyapatite discs and rinsed daily with electrolyzed saline (EOS). Corresponding positive (NaOCl) and negative (phosphate-buffered saline) controls were included. After 3 rinses, biofilms were analyzed with viability quantitative polymerase chain reaction and scanning electron microscopy. Supernatants of rinsed biofilms were used for metabolic activity analysis (high-performance liquid chromatography) through measuring organic acid content. In addition, human oral keratinocytes (HOKs) were exposed to EOS to test biocompatibility (cytotoxicity and inflammation induction) and also to rinsed biofilms to assess their immunogenicity after rinsing. Rinsing the dysbiotic biofilms with EOS could reduce the counts of the pathobionts (>3 log10 Geq/mm2 reduction) and avert biofilm dysbiosis (≤1% pathobiont abundance), leading to the dominance of commensal species (≥99%), which altered both biofilm metabolism and interleukin 8 (IL-8) induction in HOKs. EOS had no harmful effects on homeostatic biofilms. The scanning electron micrographs confirmed the same. In addition, tested concentrations of EOS did not have any cytotoxic effects and did not induce IL-8 production in HOKs. EOS showed promising results for diverting dysbiosis in in vitro rinsed biofilms and controlling key periopathogens, with no toxic effects on commensal species or human cells. This novel rinsing should be considered for clinical applications.

Oral Biofilm Cryotherapy as a Novel Ecological Modulation Approach.

Oral cryotherapy is used in dentistry as a safe, simple, and low-cost treatment for a variety of oral lesions. It is well known for its ability to aid in the healing process. However, its effect on oral biofilms is unknown. As a result, the purpose of this study was to assess the effects of cryotherapy on in vitro oral biofilms. In vitro multispecies oral biofilms were grown on the surface of hydroxyapatite discs in symbiotic or dysbiotic states. CryoPen X+ was used to treat the biofilms, whereas untreated biofilms served as control. One set of biofilms was collected for study immediately after cryotherapy, whereas another group was reincubated for 24 h to permit biofilm recovery. Changes in biofilm structure were analyzed with a confocal laser scanning microscope (CLSM) and a scanning electron microscope (SEM), while biofilm ecology and community compositional changes were analyzed with viability DNA extraction and quantitative polymerase chain reaction (v-qPCR) analysis. One cryo-cycle immediately reduced biofilm load by 0.2 to 0.4 log10 Geq/mL, which increased with additional treatment cycles. Although the bacterial load of the treated biofilms recovered to the same level as the control biofilms within 24 h, the CLSM detected structural alterations. Compositional alterations were also detected by SEM, corroborating the v-qPCR findings that showed ≈≤10% incidence of pathogenic species compared to nontreated biofilms that encompassed ≈45% and 13% pathogenic species in dysbiotic and symbiotic biofilms, respectively. Spray cryotherapy showed promising results in a novel conceptual approach to the control of oral biofilms. Acting selectively by targeting oral pathobionts and retaining commensals, spray cryotherapy could modify the ecology of in vitro oral biofilms to become more symbiotic and prevent the evolution of dysbiosis without the use of antiseptics/antimicrobials.

Anti-infective DNase I coatings on polydopamine functionalized titanium surfaces by alternating current electrophoretic deposition.

Implant-associated infections (IAIs) can cause serious problems due to the difficult-to-treat nature of the biofilms formed on the implant surface. In mature biofilms, the matrix, which consists of polysaccharides, proteins, lipids and extracellular DNA (eDNA), forms a protective environment for the residing bacteria, shielding them from antibiotics and host defenses. Recently, the indirect prevention of biofilm growth through the degradation of eDNA using an enzyme, such as deoxyribonuclease (DNase) I, has gained attention and is regarded as a promising strategy in the battle against IAIs. In this study, coatings of DNase I were applied on titanium implant materials and their anti-infective properties were investigated. First, the effectiveness of alternating current electrophoretic deposition (AC-EPD) as a novel processing route to apply DNase I on titanium was examined and compared with the commonly applied diffusion methodology (i.e. classic dipping). For the same processing time, the use of AC-EPD in combination with a polydopamine (PDA) coupling chemistry on the titanium electrode surface significantly increased the protein deposition yield as compared to classic dipping, thereby yielding homogeneous coatings with a thickness of 12.8 nm and an average surface roughness, Sa, of ∼20 nm. X-ray photoelectron spectroscopy confirmed the presence of peptide bonds on all DNase-coated substrates. Time-of-flight secondary ion mass spectrometry detected a more dense DNase I layer in the case of AC-EPD for electrodes coupled as anode during the high-amplitude half cycle of the AC signal. The enzyme activity, release kinetics, and shelf life of DNase I coatings were monitored in real-time using a quantitative qDNase assay. The activity of DNase I coatings produced using AC-EPD was three time higher than for coatings prepared by classic dipping. For both deposition methods, a high initial burst release was observed within the first 2 h, while some activity was still retained at the surface after 7 days. This can be explained by the stable attachment of a small fraction of DNase to the surface through covalent bonding to the PDA layer, while superimposing DNase deposits were only loosely bound and therefore released rapidly upon immersion in the medium. Interestingly, coatings prepared with AC-EPD exhibited a prolonged, gradual release of DNase activity. The AC-EPD DNase coatings significantly reduced biofilm formation of both Staphylococcus epidermidis and Pseudomonas aeruginosa up to 20 h, whereas DNase coatings prepared by short classic dipping only reduce S. epidermidis biofilm formation, and this to a lesser extent as compared to AC-EPD DNase coatings. Overall, this study indicates that AC-EPD allows to rapidly concentrate DNase I on PDA-functionalized titanium, while maintaining the enzyme activity and anti-infective ability. This highlights the potential of AC-EPD as a time-efficient coating strategy (as opposed to the much slower dip-coating methodologies) for bioactive molecules in a wide variety of biomedical applications.

3D-printing-assisted fabrication of chitosan scaffolds from different sources and cross-linkers for dental tissue engineering.

The aim of the present study was to fabricate and characterise chitosan scaffolds from animal and fungal sources, with or without gelatine as a co-polymer, and cross-linked to 3-glycidyloxyproply trimethoxysilane (GPTMS) or genipin for application in dental root tissue engineering. Chitosan-based scaffolds were prepared by the emulsion freeze-drying technique. Scanning electron microscopy (SEM) and nano-focus computed tomography (nano-CT) were used to characterise scaffold microstructure. Chemical composition and cross-linking were evaluated by Fourier transform infrared-attenuated total reflectance spectroscopy. Compression tests were performed to evaluate scaffold mechanical properties. Scaffold degradation was evaluated by gravimetric method and SEM. Scaffold bioactivity immersed in simulated body fluid was evaluated by SEM, with associated electron dispersive X-ray spectroscopy, and apatite formation was examined by X-ray diffraction. Finally, human dental pulp stem cells (hDPSCs) viability was evaluated. The fabrication method used was successful in producing scaffolds with organised porosity. Chitosan source (animal vs. fungal), co-polymerisation with gelatine and cross-linking using GPTMS or genipin had a significant effect on scaffold properties and hDPSCs response. Chitosan-genipin (CS-GEN) scaffolds had the largest pore diameter, while the chitosan-gelatine-GPTMS (CS-GEL-GPTMS) scaffolds had the smallest. Animal chitosan-gelatine co-polymerisation increased scaffold compressive strength, while fungal chitosan scaffolds (fCS-GEL-GPTMS) had the fastest degradation rate, losing 80 % of their weight by day 21. Gelatine co-polymerisation and GPTMS cross-linking enhanced chitosan scaffolds bioactivity through the formation of an apatite layer as well as improved hDPSCs attachment and viability. Tailored chitosan scaffolds with tuned properties and favourable hDPSCs response can be obtained for regenerative dentistry applications.

Biomaterials in temporomandibular joint replacement: current status and future perspectives-a narrative review.

The alloplastic total temporomandibular joint (TMJ) prosthesis has a long history, with many different materials and designs used. While several of these materials have proven valuable over time, many others have not been suitable for implantation, resulting in failure and the need for explantation of the implant. Because of the failure of several of these systems, the use of alloplastic prostheses has reduced dramatically, despite their advantages over autogenous restoration. The aim of this narrative review is to discuss the criteria that must be met by a biomaterial in order for it to be considered suitable for implantation, as well as the common complications that can occur. Currently used materials are highlighted, as well as potential future materials that might prove better suitable for implantation. Several surface modification techniques are proposed as an alternative to the materials used in current TMJ prosthesis systems.

Controlled release of chlorhexidine from a mesoporous silica-containing macroporous titanium dental implant prevents microbial biofilm formation.

Roughened surfaces are increasingly being used for dental implant applications as the enlarged contact area improves bone cell anchorage, thereby facilitating osseointegration. However, the additional surface area also entails a higher risk for the development of biofilm associated infections, an etiologic factor for many dental ailments, including peri-implantitis. To overcome this problem, we designed a dental implant composed of a porous titanium-silica (Ti/SiO2) composite material and containing an internal reservoir that can be loaded with antimicrobial compounds. The composite material consists of a sol-gel derived mesoporous SiO2 diffusion barrier integrated in a macroporous Ti load-bearing structure obtained by powder metallurgical processing. The antimicrobial compounds can diffuse through the porous implant walls, thereby reducing microbial biofilm formation on the implant surface. A continuous release of µM concentrations of chlorhexidine through the Ti/SiO2 composite material was measured, without initial burst effect, over at least 10 days and using a 5 mM chlorhexidine solution in the implant reservoir. Metabolic staining, CFU counting and visualisation by scanning electron microscopy confirmed that Streptococcus mutans biofilm formation on the implant surface was almost completely prevented due to chlorhexidine release (preventive setup). Moreover, we demonstrated efficacy of released chlorhexidine against mature Streptococcus mutans biofilms (curative setup). In conclusion, we provide a proof of concept of the sustained release of chlorhexidine, one of the most widely used oral antiseptics, through the Ti/SiO2 material thereby preventing and eradicating biofilm formation on the surface of the dental implant. In principle, our flexible design allows for the use of any bioactive compound, as discussed.

[Determination of vaccination quotas for pneumococcal conjugate vaccine in children on the basis of routine data of the statutory health insurance]. / Bestimmung von Impfquoten zur Pneumokokken-Konjugatimpfung bei Kindern anhand von GKV-Routinedaten.

The pneumococcal conjugate vaccine is recommended since July 2006 for all children up to 24 months by the Standing Committee on Vaccination (STIKO) in Germany. Immunisation includes 4 doses; a single dose should be administered at completed 2, 3, 4 months and 11-14 months of age. To analyse the immunization coverage, timeliness and completeness of vaccinations, a claims data analysis was conducted. The evaluation was based on routine claims data of a statutory health insurance covering the period from May 2008-September 2009. Overall, 81.2% (5 484/6 755) of all live births of mothers and fathers of the insurance received at least one vaccination dose. In 91.3% and 72.0% of these cases, the second and third dose was administered, respectively. A vaccination cycle of 4 doses was often not completed and the recommended time points for vaccination were not met in two-thirds of all children. Due to the limited and relatively short observation period, a conclusion about the rate of fully completed vaccination cycles was not possible.

Feasibility of a novel design of high resolution parallax-free Compton enhanced PET scanner dedicated to brain research.

A novel concept for a positron emission tomography (PET) camera module is proposed, which provides full 3D reconstruction with high resolution over the total detector volume, free of parallax errors. The key components are a matrix of long scintillator crystals and hybrid photon detectors (HPDs) with matched segmentation and integrated readout electronics. The HPDs read out the two ends of the scintillator package. Both excellent spatial (x, y, z) and energy resolution are obtained. The concept allows enhancing the detection efficiency by reconstructing a significant fraction of events which underwent Compton scattering in the crystals. The proof of concept will first be demonstrated with yttrium orthoaluminate perovskite (YAP):Ce crystals, but the final design will rely on other scintillators more adequate for PET applications (e.g. LSO:Ce or LaBr3:Ce). A promising application of the proposed camera module, which is currently under development, is a high resolution 3D brain PET camera with an axial field-of-view of approximately 15 cm dedicated to brain research. The design philosophy and performance predictions based on analytical calculations and Monte Carlo simulations are presented. Image correction and reconstruction tools required to operate this transmissionless device in a research environment are also discussed. Better or similar performance parameters were obtained compared to other known designs at lower fabrication cost. The axial geometrical concept also seems to be promising for applications such as positron emission mammography.

Nanoparticle halos: a new colloid stabilization mechanism.

A new mechanism for regulating the stability of colloidal particles has been discovered. Negligibly charged colloidal microspheres, which flocculate when suspended alone in aqueous solution, undergo a remarkable stabilizing transition upon the addition of a critical volume fraction of highly charged nanoparticle species. Zeta potential analysis revealed that these microspheres exhibited an effective charge buildup in the presence of such species. Scanning angle reflectometry measurements indicated, however, that these nanoparticle species did not adsorb on the microspheres under the experimental conditions of interest. It is therefore proposed that highly charged nanoparticles segregate to regions near negligibly charged microspheres because of their repulsive Coulombic interactions in solution. This type of nanoparticle haloing provides a previously unreported method for tailoring the behavior of complex fluids.