Post-processing of a 3D-printed denture base polymer: Impact of a centrifugation method on the surface characteristics, flexural properties, and cytotoxicity.

OBJECTIVES: To investigate the impact of a centrifugation method on the surface characteristics, flexural properties, and cytotoxicity of an additively manufactured denture base polymer. METHODS: The tested specimens were prepared by digital light processing (DLP). A centrifugation method (CENT) was used to remove the residual uncured resin. In addition, the specimens were post-processed with different post-rinsing solutions: isopropanol (IPA), ethanol (EtOH), and tripropylene glycol monomethyl ether (TPM), respectively. A commercial heat-polymerized polymethyl methacrylate was used as a reference (REF). First, the values of surface topography, arithmetical mean height (Sa), and root mean square height (Sq) were measured. Next, flexural strength (FS) and modulus were evaluated. Finally, cytotoxicity was assessed using an extract test. The data were statistically analyzed using a one-way analysis of variance, followed by Tukey's multiple comparison test for post-hoc analysis. RESULTS: The Sa value in the CENT group was lower than in the IPA, EtOH, TPM, and REF groups (p < 0.001). Moreover, the CENT group had lower Sq values than other groups (p < 0.001). The centrifugation method showed a higher FS value (80.92 ± 8.65 MPa) than the EtOH (61.71 ± 12.25 MPa, p < 0.001) and TPM (67.01 ± 9.751 MPa, p = 0.027), while affecting IPA (72.26 ± 8.80 MPa, p = 0.268) and REF (71.39 ± 10.44 MPa, p = 0.231). Also, the centrifugation method showed no evident cytotoxic effects. CONCLUSIONS: The surfaces treated with a centrifugation method were relatively smooth. Simultaneously, the flexural strength of denture base polymers was enhanced through centrifugation. Finally, no evident cytotoxic effects could be observed from different post-processing procedures. CLINICAL SIGNIFICANCE: The centrifugation method could optimize surface quality and flexural strength of DLP-printed denture base polymers without compromising cytocompatibility, offering an alternative to conventional rinsing post-processing.

In Vitro Study of the Proliferation of MG63 Cells Cultured on Five Different Titanium Surfaces.

The use of dental implants for prosthetic rehabilitation in dentistry is based on the concept of osteointegration. This concept enables the clinical stability of the implants and a total absence of inflammatory tissue between the implant surface and the bone tissue. For this reason, it is essential to understand the role of the titanium surface in promoting and maintaining or not maintaining contact between the bone matrix and the surface of the titanium implant. MATERIALS AND METHODS: Five types of titanium discs placed in contact with osteoblast cultures of osteosarcomas were studied. The materials had different roughness. Scanning electron microscopy (SEM) photos were taken before the in vitro culture to analyze the surfaces, and at the end of the culturing time, the different gene expressions of a broad pattern of proteins were evaluated to analyze the osteoblast response, as indicated in the scientific literature. RESULTS: It was demonstrated that the responses of the osteoblasts were different in the five cultures in contact with the five titanium discs with different surfaces; in particular, the response in the production of some proteins was statistically significant. DISCUSSION: The key role of titanium surfaces underlines how it is still possible to carry out increasingly accurate and targeted studies in the search for new surfaces capable of stimulating a better osteoblastic response and the long-term maintenance of osteointegration.

Trueness, physical properties, and surface characteristics of additive-manufactured zirconia crown.

OBJECTIVE: This study aimed to conduct a comparison of trueness and physical and surface properties among five distinct types of additive manufactured (AM) zirconia crowns and zirconia crowns produced using the subtractive manufacturing (SM). MATERIAL AND METHODS: Zirconia crowns were fabricated using five distinct techniques, each varying in the method of slurry transfer and photocuring source. Each experimental group utilized either one of the four digital light processing (DLP)-based techniques (DLP spreading, DLP spreading gradation, DLP vat and DLP circular spreading) or the stereolithography (SLA)-based technique (SLA spreading). The control (CON) group employed SM. To assess accuracy, trueness was measured between the scan and reference data. To analyze the physical properties, voids were examined using high-energy spiral micro-computed tomography scans, and the crystal structure analysis was performed using X-ray diffraction (XRD). Surface roughness was assessed through laser scanning microscopy. RESULTS: Differences in the trueness of internal surfaces of crowns were found among the groups (P < 0.05). Trueness varied across the measurement surfaces (occlusal, lateral, and marginal) in all the groups except for the DLP spreading gradation group (P < 0.05). Voids were observed in all AM groups. All groups showed similar XRD patterns. All AM groups showed significantly greater surface roughness compared to the CON group (P < 0.001). CONCLUSION: The AM zirconia crowns showed bubbles and a rougher surface compared to the SM crowns. All groups exhibited typical zirconia traits and trueness levels within clinically acceptable limits, suggesting that current zirconia AM techniques could be suitable for dental applications.

Characterization and Assessment of Native Lactic Acid Bacteria from Broiler Intestines for Potential Probiotic Properties.

Probiotics are the most promising alternative to antibiotics for improving animal production and controlling pathogenic infections, while strains derived from natural hosts are considered highly desirable due to their good adaptation to the gastrointestinal tract. The aim of this study was to screen Lactobacillus with broad-spectrum antibacterial activity from broilers fed an antibiotic-free diet and evaluate their potential as poultry probiotics. A total of 44 lactic acid bacteria (LAB) strains were isolated from the intestines of healthy broilers, among which 3 strains exhibited outstanding antimicrobial activity and were subsequently identified through 16S rRNA sequencing as Enterococcus faecium L8, Lactiplantibacillus plantarum L10, and Limosilactobacillus reuteri H11. These three isolates demonstrated potent bacteriostatic activity against Staphylococcus aureus, Listeria monocytogenes, Escherichia coli, and Salmonella cholerae, with inhibition zones ranging from 15.67 ± 1.53 to 21.33 ± 0.58 mm. The selected LAB strains exhibited high tolerance to acid and bile salts, with L. reuteri H11 displaying the highest survival rate (ranging from 34.68% to 110.28%) after exposure to 0.3% (w/v) bile salts for 6 h or a low pH environment (pH 2, 2.5, and 3) for 3 h. Notably, L. reuteri H11 outperformed other strains in terms of hydrophobicity (84.31%), auto-aggregation (53.12%), and co-aggregation with E. coli ATCC 25922 (36.81%) and S. aureus ATCC 6538 (40.20%). In addition, the three LAB isolates were either fully or moderately susceptible to the tested antibiotics, except for strain L8, which resisted gentamycin and vancomycin. Consequently, these three LAB strains, especially L. reuteri H11, isolated from the intestines of broiler chickens, represent promising probiotic candidates that can be employed as feed additives to enhance production performance and control poultry pathogens.

Surface characteristics of additively manufactured CoCr and Ti6Al4V dental alloys: The effects of carbon and gold thin film coatings, and alkali-heat treatment.

This study investigates the impact of surface modifications on additively manufactured CoCr and Ti6Al4V dental alloys, focusing on surface properties. Thin film carbon (C) and gold (Au) coatings, as well as alkali-heat treatment, were applied to the high- and low-polished specimens. Scanning electron microscopy (SEM) showed that thin film coatings retained the underlying surface topography, while the alkali-heat treatment induced distinct morphological changes. Energy-dispersive x-ray spectroscopy (EDS) analysis revealed that C-coating enriched surfaces with C, and Au-coating introduced detectable amounts of Au. Nevertheless, signs of coating delamination were observed in the high-polished specimens. Alkali-heat treatment led to the formation of a sodium titanate layer on Ti6Al4V surfaces, confirmed by sodium presence and Fourier transform infrared spectroscopy (FTIR) results showing carbonate bands. Surface roughness measurements with atomic force microscopy (AFM) showed that C-coating increased surface roughness in both high- and low-polished alloys. Au-coating slightly increased roughness, except for low-polished Au-coated Ti6Al4V, where a decrease in roughness was observed compared to low-polished bare Ti6Al4V, likely due to surface defects present in the latter resulting from the additive manufacturing process. Alkali-heat treatment led to a pronounced increase in roughness for both alloys, particularly for Ti6Al4V. Both thin film coatings decreased the water contact angles in all specimens in varying magnitudes, indicating an increase in wettability. However, the alkali-heat treatment caused a substantial decrease in contact angles, resulting in a highly hydrophilic state for Ti6Al4V. These findings underscore the substantial impact of surface modifications on additively manufactured dental alloys, potentially influencing their clinical performance. RESEARCH HIGHLIGHTS: Thin film coatings and chemical/heat treatment modify the surface properties of additively manufactured dental alloys. The surfaces of the alloys get rougher and more hydrophilic after alkali-heat treatment. Thin gold coatings exhibit potential adhesion challenges.

From organic fertilizer to the soils: What happens to the microplastics? A critical review.

In recent, soil microplastic pollution arising from organic fertilizers has been of a great increasing concern. In response to this concern, this review presents a comprehensive analysis of the occurrence and evolution of microplastics in organic fertilizers, their ingress into the soil, and the subsequent impacts. Organic fertilizers are primarily derived from solid organic waste generated by anthropocentric activities including urban (daily-life, municipal wastes and sludge), agricultural (manure, straw), and industrial (like food industrial waste etc.) processes. In order to produce organic fertilizer, the organic solid wastes are generally treated by aerobic composting or anaerobic digestion. Currently, microplastics have been widely detected in the raw materials and products of organic fertilizer. During the process of converting organic solid waste materials into fertilizer, intense oxidation, hydrolysis, and microbial actions significantly alter the physical, chemical, and surface biofilm properties of the plastics. After the organic fertilizer application, the abundances of microplastics significantly increased in the soil. Additionally, the degradation of these microplastics often promotes the adsorption of organic pollutants and affects their retention time in the soil. These microplastics, covered by biofilms, also significantly alter soil ecology due to the unique properties of the biofilm. Furthermore, the biofilms also play a role in the degradation of microplastics in the soil environment. This review offers a new perspective on the soil environmental processes involving microplastics from organic fertilizer sources and highlights the challenges associated with further research on organic fertilizers and microplastics.

Effect of post-curing conditions on surface characteristics, physico-mechanical properties, and cytotoxicity of a 3D-printed denture base polymer.

OBJECTIVE: This study aims to investigate the influence of post-polymerization (post-curing) conditions on surface characteristics, flexural properties, water sorption and solubility, and cytotoxicity of additively manufactured denture base materials. METHODS: The tested specimens were additively manufactured using digital light processing and classified into different post-curing condition groups: submerged in water (WAT), submerged in glycerin (GLY), and air exposure (AIR). An uncured specimen (UNC) was used as a control. The surface topography and roughness were observed. The flexural strength and modulus were determined via a three-point bending test. The water sorption and solubility were subsequently tested. Finally, an extract test was performed to assess cytotoxicity. RESULTS: Different post-curing conditions had no significant effects on the surface topography and roughness (Sa value). Various post-curing conditions also had no significant effects on the flexural strength. Notably, the flexural modulus of the WAT group (2671.80 ± 139.42 MPa) was significantly higher than the AIR group (2197.47 ± 197.93 MPa, p = 0.0103). After different post-curing conditions, the water sorption and solubility of the specimens met the ISO standards. Finally, all post-curing conditions effectively reduced cytotoxic effects. SIGNIFICANCES: Post-curing with different oxygen levels improved flexural properties, and flexural modulus significantly increased after the specimens were submerged in water. In addition, water sorption and solubility, and cytocompatibility were optimized by post-curing, irrespective of the post-curing conditions. Therefore, the water-submerged conditions optimized the flexural modulus of the 3D-printed denture base materials.

Evaluation of the influence of different build angles on the surface characteristics, accuracy, and dimensional stability of the complete denture base printed by digital light processing.

Purpose: This study aims to investigate the influence of the build angle on the surface characteristics, accuracy, and dimensional stability of digital light processing (DLP) printed resin bases. Material and methods: Rectangular and complete denture base samples were fabricated at 0, 45, and 90-degree angles (n = 5 for rectangular samples; n = 10 for maxillary and mandibular denture base samples) using a DLP printer. Surface morphology and roughness were assessed using a profilometer, followed by measuring hydrophilicity with a contact angle meter. Accuracy (trueness and precision) and dimensional stability were evaluated at intervals of 1, 3, 7, 14, 28, and 42 days after base printing using best-fit-alignment and deviation analysis in 3D software. Statistical analysis was performed using one-way ANOVA for surface characteristics (α = 0.05), multi-way ANOVA for accuracy and dimensional stability data, and Tukey's test for post-hoc comparisons. Results: The 0-degree group exhibited significantly lower mean roughness (1.27 ± 0.19 µm) and contact angle (80.50 ± 3.71°) (P < 0.001) compared to the 90-degree and 45-degree groups. The 0-degree build angle led to superior trueness (maxilla: 77.80 ± 9.35 µm, mandible: 61.67 ± 10.32 µm) and precision (maxilla: 27.51 ± 7.43 µm, mandible: 53.50 ± 15.16 µm) compared to other groups (P < 0.001). Maxillary base precision was superior to mandibular base precision (P < 0.001). The maxillary base exhibited less dimensional deviation than the mandibular base. The 90-degree group showed the highest deviation compared to the other two groups, and all groups' deviations increased over time (P < 0.001). Conclusions: The build angle significantly influences the surface characteristics, accuracy, and dimensional stability of DLP-printed denture bases. A 0-degree build angle provides the most favorable performance. The maxillary base displayed superior precision and dimensional stability than the mandibular base.

Nitrate reductase involves in selenite reduction in Rahnella aquatilis HX2 and the characterization and anticancer activity of the biogenic selenium nanoparticles.

BACKGROUND: Biogenic selenium nanoparticles (SeNPs) show numerous advantages including their high stability, low toxicity, and high bioactivity. While metabolism of SeNPs remains not well studied and need more investigation to reveal the process. PURPOSE: The objective of the study was to investigate the relationship between nitrate reductase and selenite reduction in Rahnella aquatilis HX2, characterize the properties of HX2 produced SeNPs, and explore their potential applications, particularly their anticancer activity. PROCEDURES: Selenium species were measured by high-performance liquid chromatography coupled to inductively coupled plasma - Mass spectrometry (HPLC-ICP-MS). Transcription level of nitrate reductase was determined by Real-time quantitative PCR. Morphology, particle size, crystal structure and surface chemistry of SeNPs were determined by electron microscopy, dynamic light scattering method, Raman scattering, X-ray photoelectron spectroscopy, respectively. Anti cancer cell activity was measured by CCK-8 assay. MAIN FINDINGS: SeNP production in R. aquatilis HX2 was correlated with the cell growth. The products of selenite reduction in HX2 detected by HPLC-ICP-MS included SeNPs, selenocysteine (SeCys), Se-Methylselenocysteine (MeSeCys), and 7 unknown compounds. Nitrate addition experiments suggested the involvement of nitrate reductase in selenite reduction in HX2. Both the cellular membrane and cytoplasm of HX2 exhibited selenite-reducing ability, indicating that membrane-associated nitrate reductase was not the sole selenite reductase in HX2. Characterization of the biogenic SeNPs revealed a spherical morphology and amorphous structure of them. Surface chemistry analysis implicated the binding of extracellular polymeric substances to the biogenic SeNPs, and the presence of Se0, Se2-, and electron-rich Se atoms on the surface of SeNPs. Finally, the IC50 values of the biogenic SeNPs were 36.49 µM for HepG2 and 3.70 µM for HeLa cells. CONCLUSIONS: The study first revealed that the nitrate reductase is involving in selenite reduction in R. aquatilis HX2. The biogenic SeNPs coordinated with organic substances in the surface. And SeNPs produced by R. aquatilis HX2 showed excellent anticancer activities on HepG2 and HeLa cells.

Heat-moisture treated waxy highland barley starch: Roles of starch granule-associated surface lipids, temperature and moisture.

Roles of temperature, moisture and starch granule-associated surface lipids (SGASL) during heat-moisture treatment (HMT) of waxy highland barley starch were elucidated. Starch without SGASL showed a higher increase in ratio (1016/993 cm-1) (0.095-0.121), lamellar peak area (88), radius of gyration (Rg1, 0.9-1.8 nm) and power-law exponents (0.19-0.42) than native starch (0.038-0.047, 46, 0.1-0.6 nm, 0.04-0.14), upon the same increase in moisture or temperature. Thus, removing SGASL promoted HMT. However, after HMT (30 % moisture, 120 °C), native starch showed lower relative crystallinity (RC, 11.67 %) and lamellar peak area (165.0), longer lamellar long period (L, 14.99 nm), and higher increase in peak gelatinization temperature (9.2-13.3 °C) than starch without SGASL (12.04 %, 399.2, 14.52 nm, 4.7-6.1 °C). This suggested that the resulting SGASL-amylopectin interaction further destroyed starch structure. Starch with and without SGASL showed similar trends in RC, lamellar peak area, L and Rg1 with increasing temperature, but different trends with increasing moisture, suggesting that removing SGASL led to more responsiveness to the effects of increasing moisture. Removing SGASL resulted in similar trends (RC and lamellar peak area) with increasing moisture and temperature, suggesting that the presence of SGASL induced different effects on moisture and temperature.

Dried blood drops on vertical surfaces.

The analysis of structures in dried droplets has made it possible to detect the presence and conformational state of macromolecules in relevant biofluids. Therefore, the implementation of novel drying strategies for pattern formation could facilitate the identification of biomarkers for the diagnosis of pathologies. We present an experimental study of patterns formed by evaporating water-diluted blood droplets on a vertical surface. Three significant morphological features were observed in vertical droplet deposits: (1) The highest concentration of non-volatile molecules is consistently deposited in the lower part of the droplet, regardless of erythrocyte concentration. (2) The central region of deposits decreases rapidly with hematocrit; (3) At high erythrocyte concentrations (36-40% HCT), a broad coating of blood serum is produced in the upper part of the deposit. These findings are supported by the radial intensity profile, the relative thickness of the crown, the aspect ratio of the deformation, the relative area of the central region, and the Entropy of the Gray Level Co-occurrence Matrix Entropy (GLCM). Moreover, we explore the pattern formation during the drying of vertical blood drops. We found that hematocrit concentration has a significant impact on droplet drying dynamics. Finally, we conducted a proof-of-concept test to investigate the impact of vertical droplet evaporation on blood droplets with varying lipid concentrations. The results revealed that it is possible to differentiate between deposits with normal, slightly elevated, and moderately elevated lipid levels using only the naked eye.

Effect of Post-Washing on Textural Characteristics of Carbon Materials Derived from Pineapple Peel Biomass.

Porous carbon materials have been widely used to remove pollutants from the liquid-phase streams. However, their limited pore properties could be a major problem. In this work, the effects of post-washing methods (i.e., water washing and acid washing) on the textural characteristics of the resulting biochar and activated carbon products from pineapple peel biomass were investigated in the carbonization and CO2 activation processes. The experiments were set at an elevated temperature (i.e., 800 °C) holding for 30 min. It was found that the enhancement in pore property reached about a 50% increase rate, increasing from 569.56 m2/g for the crude activated carbon to the maximal BET surface area of 843.09 m2/g for the resulting activated carbon by water washing. The resulting activated carbon materials featured the microporous structures but also were characteristic of the mesoporous solids. By contrast, the enhancement in the increase rate by about 150% was found in the resulting biochar products. However, there seemed to be no significant variations in pore property with post-washing methods. Using the energy dispersive X-ray spectroscopy (EDS) and the Fourier Transform infrared spectroscopy (FTIR) analyses, it showed some oxygen-containing functional groups or complexes, potentially posing the hydrophilic characters on the surface of the resulting carbon materials.

Effect of Erbium:YAG Laser Recycling on Mechanical Characteristics of Retrieved Orthodontic Mini-screws.

Introduction: This study aimed to evaluate the influence of two recycling methods on the mechanical and surface characteristics of orthodontic mini-screws. Methods: Thirty-six retrieved mini-screws were randomly classified into two equal groups. In the first group (laser recycled group (LG)), the Er:YAG laser (2940 nm, 5.5 W, 275 mJ, perpendicular to the mini-screws at a distance of 7-10 mm, 25 s) was used to recycle mini-screws. In the second group (phosphoric acid and sodium hypochlorite recycled group (ASG)), the mini-screws were kept in 37% phosphoric acid gel (10 minutes) and then placed in 5.25% sodium hypochlorite for 30 minutes. Eighteen new mini-screws were selected as the control group (CG). Maximum insertion torque (MIT), maximum removal torque (MRT), and fracture torque (FT) of all mini-screws were measured. A sample from each group was examined for the surface changes of the mini-screw and tissue remnants under a scanning electron microscope (SEM). Results: The mean MIT was significantly higher in both LG and ASG groups than the CG (P<0.001 and P=0.002, respectively). However, no significant difference was shown between the LG and ASG groups. The mean values of MRT and FT showed no significant difference between the groups. The amount of tissue remnants in the ASG group was significantly higher than that in the LG group. The evidence of porosity and corrosion was observed on the ASG mini-screw surface, and there was an increase in roughness on the LG mini-screw surface. Conclusion: The Er:YAG laser recycling of mini-screws is a proper method causing minimum damage to the screw surface.

Enhancing the mechanical properties and surface morphology of individualized Ti-mesh fabricated through additive manufacturing for the treatment of alveolar bone defects.

Titanium meshes are widely utilized in alveolar bone augmentation, and this study aims to enhance the properties of titanium meshes through heat treatment (HT) and the synergistic finishing technology of electric field and flow field (EFSF). Our findings illustrate that the titanium mesh exhibits improved mechanical properties following HT treatment. The innovative EFSF technique, in combination with HT, has a substantial impact on improving the surface properties of titanium meshes. HT initiates grain fusion and reduces surface pores, resulting in enhanced tensile and elongation properties. EFSF further enhances these improvements by significantly reducing surface roughness and eliminating adhered titanium powder, a byproduct of selective laser melting printing. Increased hydrophilicity and surface-free energy are achieved after EFSF treatment. Notably, the EFSF-treated titanium mesh exhibits reduced bacterial adhesion and is non-toxic to osteoblast proliferation. These advancements increase its suitability for clinical alveolar bone augmentation.

Study of silicone hydrogel contact lenses' surface reflection characteristics using confocal microscopy.

The physical and chemical properties of contact lenses (CLs) differ significantly from one another. This is already covered by the FDA classification, which divides soft lenses into groups and subgroups for additional characteristics. The differences relate to both the interior and surface of the lens. Several differences in the surface characteristics of individual contact lenses have been studied and demonstrated to date. However, one of their fundamental physical properties, that is light reflection or, quantitatively, reflectance has not been compared. This paper describes the surface differences of a range of silicone-hydrogel (SiHy) lenses using reflectance confocal microscopy. It shows the relationship between the amount of light reflected from the lens surface and the material parameters. Common SiHy lens materials were used in the study, including two lenses with surface modifications. Light incident at the interface between two media (phosphate-buffered saline and lens) with different refractive indices is partially reflected. The normalized results show significant differences between the reflection signals (1 vs 0.07), and that they are not correlated with the refractive index (R2 = 0.5536). For the water content (%H2O), a general trend was observed that the higher the %H2O, the lower the reflection signal is (R2 = 0.8105). The reflection signal and surface modulus show the best correlation. (R2 = 0.9883). The proposed CLs analysis method, using reflectance confocal microscopy, provides data to differentiate between lenses with and without surface modifications.

Effect of Sodium Flouride Mouthwash and Ozone-Infused Oil Pulling Solution With Coconut Oil on Mechanical Properties and Surface Characterization of Copper-Nickel-Titanium Orthodontic Archwires.

AIMS AND OBJECTIVES: To determine the impact on the mechanical properties and surface characteristics of prefabricated 0.016" copper-nickel-titanium (Cu-Ni-Ti) type 35oC (Ormco Company, USA) archwires when subjected to 0.05% sodium fluoride (NaF) mouthwash (ACT Anti-Cavity Fluoride Mouthwash, Sanofi Company, USA) and ozone-infused oil-pulling solution with coconut oil (O3) (O3 Essentials, Health Ranger Store, USA). MATERIALS AND METHODS: Sixty samples of preformed maxillary 0.016" Cu-Ni-Ti archwires were cut at the straight posterior ends for a length of 25 mm and then equally distributed into three groups (n=20). Each group of wires was immersed in distilled water (dH2O), NaF, and O3 solutions for 90 minutes at 37oC. All samples were taken out of their solutions and washed with distilled water prior to testing. On a universal testing device, a three-point bending test was performed on 15 samples. Yield strength (YS), flexural modulus of elasticity (E), and springback ratio (YS/E) were calculated. The remaining five samples from respective solutions were observed under a scanning electron microscope (SEM) for surface topography evaluation. RESULTS: The mean differences in loading YS, E, and YS/E between NaF and O3 are 41.14 MPa, 4.58 GPa, and -0.0006 whereas unloading values are 23.45 MPa, 4.38 GPa, and -0.0004, respectively with a statistical significance of <0.001. Surface topography alteration was appreciated in the NaF mouthwash group compared to the O3 solution. CONCLUSIONS: The mechanical properties of 0.016" Cu-Ni-Ti archwires during loading and unloading were changed after exposure to NaF mouthwash and O3 solution. The mechanical properties of Cu-Ni-Ti archwires were more negatively affected by NaF mouthwash than by O3 solution. Sodium fluoride mouthwash offers more corrosive changes when compared with the O3 solution.

Amperometric Biosensor for Quantitative Measurement Using Sandwich Immunoassays.

State-of-the-art clinical detection methods typically involve standard immunoassay methods, requiring specialized equipment and trained personnel. This impedes their use in the Point-of-Care (PoC) environment, where ease of operation, portability, and cost efficiency are prioritized. Small, robust electrochemical biosensors provide a means with which to analyze biomarkers in biological fluids in PoC environments. Optimized sensing surfaces, immobilization strategies, and efficient reporter systems are key to improving biosensor detection systems. The signal transduction and general performance of electrochemical sensors are determined by surface properties that link the sensing element to the biological sample. We analyzed the surface characteristics of screen-printed and thin-film electrodes using scanning electron microscopy and atomic force microscopy. An enzyme-linked immunosorbent assay (ELISA) was adapted for use in an electrochemical sensor. The robustness and reproducibility of the developed electrochemical immunosensor were investigated by detecting Neutrophil Gelatinase-Associated Lipocalin (NGAL) in urine. The sensor showed a detection limit of 1 ng/mL, a linear range of 3.5-80 ng/mL, and a CV% of 8%. The results demonstrate that the developed platform technology is suitable for immunoassay-based sensors on either screen-printed or thin-film gold electrodes.

Fucoidan-Containing, Low-Adhesive Siloxane Coatings for Medical Applications: Inhibition of Bacterial Growth and Biofilm Development.

The deposition of low-adhesive siloxane coatings is a current trend for the non-toxic control of bacterial growth and biofilm formation. Total elimination of biofilm formation has not been reported so far. The aim of this investigation was to study the ability of a non-toxic, natural, biologically active substance, such as fucoidan, to inhibit bacterial growth on similar medical coatings. The fucoidan amount was varied, and its impact on the bioadhesion-influencing surface characteristics, as well as on bacterial cell growth, was investigated. The inclusion of up to 3-4 wt.% brown algae-derived fucoidan in the coatings increases their inhibitory effect, more significantly on the Gram-positive bacterium S. aureus than on the Gram-negative bacterium Escherichia coli. The biological activity of the studied siloxane coatings was ascribed to the formation of a low-adhesive, biologically active surface top layer consisting of siloxane oil and dispersed water-soluble fucoidan particles. This is the first report on the antibacterial activity of fucoidan-containing medical siloxane coatings. The experimental results give reason to expect that relevantly selected, natural biologically active substances can be efficient in the non-toxic control of bacterial growth on medical devices and, as a result, medical device-associated infections.

Healing of Endosseous Implants Having Different Surface Characteristics in the Alveolar Bone: A Clinical Study.

Background Total treatment time in implant placement can be significantly reduced by placing immediate implants into the freshly extracted sockets. Also, immediate implant placement can act as a guide for proper and accurate implant placement. Additionally, in immediate implant placement, the resorption of bone associated with the healing of the extraction socket is also reduced. This clinical study aimed to clinically and radiographically assess the healing of endosseous implants having different surface characteristics in nongrafted and grafted bone. Methodology In 68 subjects, 198 implants were placed, including 102 oxidized (TiUnite, Göteborg, Sweden) and 96 turned surface implants (Nobel Biocare Mark III, Göteborg) were placed. Survival was considered with clinical stability and acceptable function with no discomfort and no radiographic or clinical signs of pathology/infection. Rest cases that showed no healing and implant no osseointegration were considered failures. Clinical and radiographic examination was done by two experts after two years of loading based on bleeding on probing (BOP) mesially and distally, radiographic marginal bone levels, and probing depth (mesial and distal). Results Five implants failed in total where four implants were with the turned surface (Nobel Biocare Mark III) and one was from the oxidized surface (TiUnite). The one oxidized implant was in a 62-year-old female and was placed in the region of mandibular premolar (44) of length 13 mm and was lost within five months of placement before functional loading. Mean probing depth had a nonsignificant difference between oxidized and turned surfaces with the mean values of 1.6 ± 1.2 and 1.5 ± 1.0 mm, respectively, with P = 0.5984; mean BOP in oxidized and turned surfaces was 0.3 ± 0.7 and 0.4 ± 0.6, respectively (P = 0.3727). Marginal bone levels, respectively, were 2.0 ± 0.8 and 1.8 ± 0.7 mm (P = 0.1231). In marginal bone levels related to implant loading, a nonsignificant difference was seen in early loading and one-stage loading with P-values of 0.06 and 0.09, respectively. However, in two-stage placement, significantly higher values were seen for oxidized surfaces (2.4 ± 0.8 mm) compared to turned surfaces (1.9 ± 0.8 mm), with P = 0.0004. Conclusions This study concludes that nonsignificantly higher survival rates are associated with oxidized surfaces compared to turned surfaces after two years of follow-up. Higher marginal bone levels were seen in oxidized surfaces for single implants and implants placed in two stages.

The Ionization of Polymeric Materials Accelerates Protein Deposition on Hydrogel Contact Lens Material.

Contact lens materials include polymers that are ionized in the ocular pH condition and are susceptible to protein deposition due to their surface characteristics. Herein, we investigated the effect of the electrostatic state of the contact lens material and protein on protein deposition level using hen egg white lysozyme (HEWL) and bovine serum albumin (BSA) as model proteins and etafilcon A and hilafilcon B as model contact lens materials. Only HEWL deposition on etafilcon A showed a statistically significant pH-dependency (p < 0.05); protein deposition increased with pH. HEWL showed a positive zeta potential at acidic pH, while BSA showed a negative zeta potential at basic pH. Only etafilcon A showed a statistically significant pH-dependent point of zero charge (PZC) (p < 0.05), implying that its surface charge became more negative under basic conditions. This pH-dependency of etafilcon A is attributed to the pH-responsive degree of ionization of its constituent methacrylic acid (MAA). The presence of MAA and its degree of ionization could accelerate protein deposition; more HEWL deposited as pH increased despite the weak positive surface charge of HEWL. The highly negatively charged etafilcon A surface attracted HEWL, even overwhelming weak positive charge of HEWL, increasing the deposition with pH.