Bacterial pathogens deliver water- and solute-permeable channels to plant cells.

Many animal- and plant-pathogenic bacteria use a type III secretion system to deliver effector proteins into host cells1,2. Elucidation of how these effector proteins function in host cells is critical for understanding infectious diseases in animals and plants3-5. The widely conserved AvrE-family effectors, including DspE in Erwinia amylovora and AvrE in Pseudomonas syringae, have a central role in the pathogenesis of diverse phytopathogenic bacteria6. These conserved effectors are involved in the induction of 'water soaking' and host cell death that are conducive to bacterial multiplication in infected tissues. However, the exact biochemical functions of AvrE-family effectors have been recalcitrant to mechanistic understanding for three decades. Here we show that AvrE-family effectors fold into a ß-barrel structure that resembles bacterial porins. Expression of AvrE and DspE in Xenopus oocytes results in inward and outward currents, permeability to water and osmolarity-dependent oocyte swelling and bursting. Liposome reconstitution confirmed that the DspE channel alone is sufficient to allow the passage of small molecules such as fluorescein dye. Targeted screening of chemical blockers based on the predicted pore size (15-20 Å) of the DspE channel identified polyamidoamine dendrimers as inhibitors of the DspE/AvrE channels. Notably, polyamidoamines broadly inhibit AvrE and DspE virulence activities in Xenopus oocytes and during E. amylovora and P. syringae infections. Thus, we have unravelled the biochemical function of a centrally important family of bacterial effectors with broad conceptual and practical implications in the study of bacterial pathogenesis.

Pseudohoeflea coraliihabitans sp. nov., a poly-ß-hydroxybutyrate-producing, halotolerant bacterium isolated from coral sediment in the Dapeng peninsula (Guangdong, China).

A Gram-stain-negative, strictly aerobic, motile, flagellated, rod-shaped, halotolerant, and poly-ß-hydroxyalkanoate-producing bacterium, designated DP4N28-3T, was isolated from offshore sediment surrounding hard coral in the Dapeng peninsula (Guangdong, PR China). Growth occurred at 15-35 °C (optimal at 30 °C), pH 6.0-9.5 (optimal at 6.0-7.0), and 0.0-30.0 % NaCl concentration (w/v, optimal at 0.0-2.0 %), showing halotolerance. Phylogeny based on 16S rRNA gene sequences, five housekeeping genes, and genome sequences identified Pseudohoeflea suaedae DSM 23348T (98.1 %, 16S rRNA gene sequence similarity) as the most related species to strain DP4N28-3T. Average nucleotide identity, digital DNA-DNA hybridization, and average amino acid identity values between strain DP4N28-3T and P. suaedae DSM 23348T were all below the threshold of species demarcation. Major phenotypic differences were the flagella type and the limited sources of single carbon utilization by strain DP4N28-3T, which only included acetic acid, acetoacetic acid, d-glucuronic acid, and glucuronamide. Strain DP4N28-3T harboured the class I poly-ß-hydroxyalkanoate synthase gene (phaC) and produced poly-ß-hydroxybutyrate. The fatty acids were summed feature 8 (C18 : 1 ω6c and/or C18 : 1 ω7c, 49.4 %) and C16 : 0 (13.4 %). The major cellular polar lipids consisted of phosphatidylcholine, phosphatidylethanolamine, phosphatidylmonomethylethanolamine, phosphatidylglycerol, and sulfoquinovosyl diacylglycerol. The respiratory quinone was Q-10. The results of the phylogenetic, genomic, phenotypic, and chemotaxonomic analysis indicated that the isolated strain represents the type strain of a novel species. Based on these results, strain DP4N28-3T (=MCCC 1K05639T=KCTC 82803T) is proposed as the type strain of the novel species Pseudohoeflea coraliihabitans sp. nov.

Characterization of Virus-Inducible Orchid Argonaute 5b Promoter and Its Functional Characterization in Nicotiana benthamiana during Virus Infection.

Plant ARGONAUTES (AGOs) play a significant role in the defense against viral infection. Previously, we have demonstrated that AGO5s encoded in Phalaenopsis aphrodite subsp. formosana (PaAGO5s) took an indispensable part in defense against major viruses. To understand the underlying defense mechanism, we cloned PaAGO5s promoters (pPaAGO5s) and analyzed their activity in transgenic Nicotiana benthamiana using ß-glucuronidase (GUS) as a reporter gene. GUS activity analyses revealed that during Cymbidium mosaic virus (CymMV) and Odontoglossum ringspot virus (ORSV) infections, pPaAGO5b activity was significantly increased compared to pPaAGO5a and pPaAGO5c. Analysis of pPaAGO5b 5'-deletion revealed that pPaAGO5b_941 has higher activity during virus infection. Further, yeast one-hybrid analysis showed that the transcription factor NbMYB30 physically interacted with pPaAGO5b_941 to enhance its activity. Overexpression and silencing of NbMYB30 resulted in up- and downregulation of GUS expression, respectively. Exogenous application and endogenous measurement of phytohormones have shown that methyl jasmonate and salicylic acid respond to viral infections. NbMYB30 overexpression and its closest related protein, PaMYB30, in P. aphrodite subsp. formosana reduced CymMV accumulation in P. aphrodite subsp. formosana. Based on these discoveries, this study uncovers the interaction between virus-responsive promoter and the corresponding transcription factor in plants.

Antioxidants protect against gingival overgrowth induced by cyclosporine A.

OBJECTIVE: We investigated the importance of reactive oxygen species (ROS) on developing gingival overgrowth (GO) and then introduced the antioxidant strategy to prevent, or even reduce GO. BACKGROUND: Gingival overgrowth is a common side effect of the patients receiving cyclosporine A (CsA), an immune suppressant. Although it has been broadly investigated, the exact pathogenesis of the induced GO is still uncertain. METHODS: We cultured human primary gingival fibroblasts and used animal model of GO to investigate the ameliorative effects of antioxidants on CsA-induced GO. To examine the CsA-induced oxidative stress, associated genes and protein expression, and the overgrown gingiva of rats by using immunocytochemistry, confocal laser scanning microscopy, real-time PCR, ELISA, gelatin zymography, gingival morphological, and immunohistochemical analysis. RESULTS: We found for the first time that ROS was responsible for the CsA-induced oxidative stress and TGF-ß1 expression in human primary gingival fibroblasts, as well as the GO of rats. The antioxidants (oxidative scavenger of vitamin E and an antioxidative enzyme inducer of hemin) ameliorated CsA-induced pathological and morphological alterations of GO without affected the CsA-suppressed il-2 expression in rats. CsA-induced oxidative stress, HO-1, TGF-ß1, and type II EMT were also rescued by antioxidants treatment. CONCLUSIONS: We concluded that CsA repetitively stimulating the production of ROS is the cause of CsA-GO which is ameliorated by treating antioxidants, including vitamin E and sulforaphane. Furthermore, the immunosuppressive effect of CsA is not interfered by antioxidant treatments in rats. This finding may thus help the clinician devise better prevention strategies in patients susceptible to GO.

Combined Treatment of Heteronemin and Tetrac Induces Antiproliferation in Oral Cancer Cells.

BACKGROUND: Heteronemin, a marine sesterterpenoid-type natural product, possesses an antiproliferative effect in cancer cells. In addition, heteronemin has been shown to inhibit p53 expression. Our laboratory has demonstrated that the thyroid hormone deaminated analogue, tetrac, activates p53 and induces antiproliferation in colorectal cancer. However, such drug mechanisms are still to be studied in oral cancer cells. METHODS: We investigated the antiproliferative effects by Cell Counting Kit-8 and flow cytometry. The signal transduction pathway was measured by Western blotting analyses. Quantitative PCR was used to evaluate gene expression regulated by heteronemin, 3,3',5,5'-tetraiodothyroacetic acid (tetrac), or their combined treatment in oral cancer cells. RESULTS: Heteronemin inhibited not only expression of proliferative genes and Homo Sapiens Thrombospondin 1 (THBS-1) but also cell proliferation in both OEC-M1 and SCC-25 cells. Remarkably, heteronemin increased TGF-ß1 expression in SCC-25 cells. Tetrac suppressed expression of THBS-1 but not p53 expression in both cancer cell lines. Furthermore, the synergistic effect of tetrac and heteronemin inhibited ERK1/2 activation and heteronemin also blocked STAT3 signaling. Combined treatment increased p53 protein and p53 activation accumulation although heteronemin inhibited p53 expression in both cancer cell lines. The combined treatment induced antiproliferation synergistically more than a single agent. CONCLUSIONS: Both heteronemin and tetrac inhibited ERK1/2 activation and increased p53 phosphorylation. They also inhibited THBS-1 expression. Moreover, tetrac suppressed TGF-ß expression combined with heteronemin to further enhance antiproliferation and anti-metastasis in oral cancer cells.

Damping ratio analysis of tooth stability under various simulated degrees of vertical alveolar bone loss and different root types.

BACKGROUND: The purpose of this study was to evaluate the feasibility of using damping ratio (DR) analysis combined with resonance frequency (RF) and periotest (PTV) analyses to provide additional information about natural tooth stability under various simulated degrees of alveolar vertical bone loss and various root types. METHODS: Three experimental tooth models, including upper central incisor, upper first premolar, and upper first molar were fabricated using Ti6Al4V alloy. In the tooth models, the periodontal ligament and alveolar bone were simulated using a soft lining material and gypsum, respectively. Various degrees of vertical bone loss were simulated by decreasing the surrounding bone level apically from the cementoenamel junction in 2-mm steps incrementally downward for 10 mm. A commercially available RF analyzer was used to measure the RF and DR of impulse-forced vibrations on the tooth models. RESULTS: The results showed that DRs increased as alveolar vertical bone height decreased and had high coefficients of determination in the linear regression analysis. The damping ratio of the central incisor model without a simulated periodontal ligament were 11.95 ± 1.92 and 27.50 ± 0.67% respectively when their bone levels were set at 2 and 10 mm apically from the cementoenamel junction. These values significantly changed to 28.85 ± 2.54% (p = 0.000) and 51.25 ± 4.78% (p = 0.003) when the tooth model was covered with simulated periodontal ligament. Moreover, teeth with different root types showed different DR and RF patterns. Teeth with multiple roots had lower DRs than teeth with single roots. CONCLUSION: Damping ratio analysis combined with PTV and RF analysis provides more useful information on the assessment of changes in vertical alveolar bone loss than PTV or RF analysis alone.

Adult Stem Cells Seeded on Electrospinning Silk Fibroin Nanofiberous Scaffold Enhance Wound Repair and Regeneration.

Development of novel strategy stimulating the healing with skin appendages regeneration is the critical goal for wound therapy. In this study, influence of the transplantation of bone marrow derived mesenchymal stem cells (MSCs) and epidermal stem cells (ESCs) with the nanofiberous scaffold prepared from silk fibroin protein in wound re-epithelization, collagen synthesis, as well as the skin appendages regeneration were investigated. It was shown that both the transplantation of MSCs and ESCs could significantly accelerate the skin re-epithelization, stimulate the collagen synthesis. Furthermore, the regenerative features of MSCs and ESCs in activating the blood vessels and hair follicles formation, respectively were suggested. These results demonstrated that the electrospinning nanofiberous scaffold is an advantageous carrier for the cells transplantation, but also provided the experimental proofs for the application of MSCs and ESCs as promising therapeutics in skin tissue engineering.

2,3,5,4'-Tetrahydroxystilbene-2-O-ß-glucoside Isolated from Polygoni Multiflori Ameliorates the Development of Periodontitis.

Periodontitis, a chronic infection by periodontopathic bacteria, induces uncontrolled inflammation, which leads to periodontal tissue destruction. 2,3,5,4'-Tetrahydroxystilbene-2-O-beta-glucoside (THSG), a polyphenol extracted from Polygoni Multiflori, reportedly has anti-inflammatory properties. In this study, we investigated the mechanisms of THSG on the Porphyromonas gingivalis-induced inflammatory responses in human gingival fibroblasts and animal modeling of ligature-induced periodontitis. Human gingival fibroblast cells were treated with lipopolysaccharide (LPS) extracted from P. gingivalis in the presence of resveratrol or THSG to analyze the expression of TNF-α, IL-1ß, and IL-6 genes. Increased AMP-activated protein kinase (AMPK) activation and SirT1 expression were induced by THSG. Treatment of THSG decreased the expression of LPS-induced inflammatory cytokines, enhanced AMPK activation, and increased the expression of SirT1. In addition, it suppressed the activation of NF-κB when cells were stimulated with P. gingivalis LPS. The anti-inflammatory effect of THSG and P. Multiflori crude extracts was reproduced in ligature-induced periodontitis animal modeling. In conclusion, THSG inhibited the inflammatory responses of P. gingivalis-stimulated human gingival fibroblasts and ameliorated ligature-induced periodontitis in animal model.

Static magnetic field increases survival rate of dental pulp stem cells during DMSO-free cryopreservation.

Successful and efficient cryopreservation of living cells and organs is a key clinical application of regenerative medicine. Recently, magnetic cryopreservation has been reported for intact tooth banking and cryopreservation of dental tissue. The aim of this study was to assess the cryoprotective effects of static magnetic fields (SMFs) on human dental pulp stem cells (DPSCs) during cryopreservation. Human DPSCs isolated from extracted teeth were frozen with a 0.4-T or 0.8-T SMF and then stored at -196 °C for 24 h. During freezing, the cells were suspended in freezing media containing with 0, 3 or 10% DMSO. After thawing, the changes in survival rate of the DPSCs were determined by flow cytometry. To understand the possible cryoprotective mechanisms of the SMF, the membrane fluidity of SMF-exposed DPSCs was tested. The results showed that when the freezing medium was DMSO-free, the survival rates of the thawed DPSCs increased 2- or 2.5-fold when the cells were exposed to 0.4-T or 0.8-T SMFs, respectively (p < 0.01). In addition, after exposure to the 0.4-T SMF, the fluorescence anisotropy of the DPSCs increased significantly (p < 0.01) in the hydrophilic region. These results show that SMF exposure improved DMSO-free cryopreservation. This phenomenon may be due to the improvement of membrane stability for resisting damage caused by ice crystals during the freezing procedure.

Long-term stimulation of areca nut components results in increased chemoresistance through elevated autophagic activity.

BACKGROUND: We previously demonstrated the autophagy-inducing activity in the crude extract of areca nut (ANE) and its 30-100 kDa fraction (ANE 30-100 K). This study aimed to analyze whether chronic ANE and ANE 30-100 K stimulations lead to higher stress resistance and autophagic activity in oral cells, and whether the resulting autophagic status in stimulated cells correlates with stress resistance. MATERIALS AND METHODS: Malignant cells from the mouth oral epidermoid carcinoma Meng-1 (OECM-1) and blood (Jurkat T) origins were stimulated with non-cytotoxic ANE and ANE 30-100 K for 3 months. Sensitivity to anticancer drugs of and autophagy status in stimulated cells, analyzed respectively by XTT assay and calculating microtubule-associated protein 1 light chain 3-II LC3-II/ß-actin ratios from Western blot, were compared to non-treated cells. Autophagy inhibitors, 3-methyladenine (3-MA) and chloroquine (CQ), were used to assess whether autophagy inhibition interferes the altered chemoresistance. RESULTS: Areca nut extract-stimulated (ANE-s) and ANE 30-100 K-stimulated (30-100 K-s) OECM-1 and Jurkat T cells generally exhibited higher cisplatin and 5-fluorouracil (5-FU) resistances, compared to non-stimulated cells. Most stimulated cells expressed significantly higher levels of LC3-II and Atg4B proteins. Interestingly, these cells also showed stronger tolerances against hypoxia environment and expressed higher LC3-II levels under glucose-deprived and hypoxia conditions. Finally, both 3-MA and CQ alleviated, albeit to different degrees, the increased chemoresistance in ANE-s and/or 30-100 K-s cells. CONCLUSIONS: Chronic stimulations of ANE or ANE 30-100 K may increase tolerance of oral cancer and leukemia T cells to anticancer drugs, as well as to glucose deprivation and hypoxia conditions, and cause an elevation of autophagy activity responsible for increased drug resistance.

The effect of phase contents on the properties of yttria stabilized zirconia dental materials fabricated by stereolithography-based additive manufacturing.

The aim is to investigate the impact of phase contents on mechanical properties, translucency, and aging stability of additively manufactured yttria partially stabilized zirconia ceramics. For that purpose, we evaluated two PSZ materials. The first type was prepared utilizing commercially available 5 mol% yttria-stabilized zirconia(5Y-PSZ), while the second type, denoted as 3Y+8Y-PSZ ceramics, was fabricated by blending 3 mol% and 8 mol% yttria-stabilized zirconia powders. Compared to 5Y-PSZ (39.90 wt% tetragonal phases and c/a2 = 1.0141), 3Y+8Y-PSZ is characterized by a greater abundance of tetragonal phases (47.68 wt%), which display higher tetragonality (c/a2 = 1.0165) and lower yttrium oxide content (2.25mol%). As a result, the 3Y+8Y-PSZ demonstrates elevated strength (816.52 MPa) and toughness (4.32 MPa m1/2), accompanied by reduced translucency(CR:0.47) and it exhibits greater susceptibility to aging. The phase contents, yttrium oxide content, and lattice parameters in the tetragonal phase play a crucial role in determining the mechanical properties, translucency, and aging stability of PSZ ceramics.

Evaluation of the efficiency, trueness, and clinical application of novel artificial intelligence design for dental crown prostheses.

OBJECTIVE: The unique structure of human teeth limits dental repair to custom-made solutions. The production process requires a lot of time and manpower. At present, artificial intelligence (AI) has begun to be used in the medical field and improve efficiency. This study attempted to design a variety of dental restorations using AI and evaluate their clinical applicability. METHODS: Using inlay and crown restoration types commonly used in dental standard models, we compared differences in artificial wax-up carving (wax-up), artificial digital designs (digital) and AI designs (AI). The AI system was designed using computer calculations, and the other two methods were designed by humans. Restorations were made by 3D printing resin material. Image evaluations were compared with cone beam computed tomography (CBCT) by calculating the root mean squared error. RESULTS: Surface truth results showed that AI (68.4 µm) and digital-designed crowns (51.0 µm) had better reproducibility. Using AI for the crown reduced the time spent by 400% (compared to digital) and 900% (compared to wax-up). Optical microscopic and CBCT images showed that AI and digital designs had close margin gaps (p < 0.05). The margin gap of the crown showed that the wax-up group was 4.1 and 4.3 times greater than those of the AI and digital crowns, respectively. Therefore, the utilization of artificial intelligence can assist in the production of dental restorations, thereby enhancing both production efficiency and accuracy. SIGNIFICANCE: It is expected that the development of AI can contribute to the reproducibility, efficiency, and goodness of fit of dental restorations.

Effect of various post-curing light intensities, times, and energy levels on the color of 3D-printed resin crowns.

Background/purpose: Current 3D-printing technology has been widely used for creating dental resin restorations. This study aimed to evaluate the effect of light intensity, time, and energy post-curing on the surface color of 3D-printed resin crowns. However, the influences of post-curing parameters on the restoration after printing still need to be explored. Therefore, this project investigates the effect of post-cure conditions on resin color. Materials and methods: Specimens from single-crown (SC) and pontic (PO) specimens underwent post-curing at various light intensities (105, 210, 420, 630, and 860 mW/cm2) for 5, 10, and 15 min. Specimens were observed at three predetermined points and measured using a commercial spectrophotometer that utilizes the CIE Lab∗ color space. Subsequently, samples were analyzed for color differences (ΔE). Results: ΔE color differences in evaluated samples were influenced by the light intensity, time, and energy post-curing. SC samples showed a significant color difference (P < 0.05), with the lowest value at 5 min of 16 (860 mW/cm2), while 10 and 15 min had a difference of 4 (210 mW/cm2). PO samples exhibited a significant decrease in the color difference (P < 0.05) at 5 and 10 min of 16 (860 mW/cm2), and at 15 min of 12 (630 mW/cm2). Conclusion: The results of this study indicate that exposing a resin crown to a high light intensity results in color stability and allows shorter post-curing times.

Applying machine learning to assess the morphology of sculpted teeth.

Background/purpose: Producing tooth crowns through dental technology is a basic function of dentistry. The morphology of tooth crowns is the most important parameter for evaluating its acceptability. The procedures were divided into four steps: tooth collection, scanning skills, use of mathematical methods and software, and machine learning calculation. Materials and methods: Dental plaster rods were prepared. The effective data collected were to classify 121 teeth (15th tooth position), 342 teeth (16th tooth position), 69 teeth (21st tooth position), and 89 teeth (43rd tooth position), for a total of 621 teeth. The procedures are divided into four steps: tooth collection, scanning skills, use of mathematical methods and software, and machine learning calculation. Results: The area under the curve (AUC) value was 0, 0.5, and 0.72 in this study. The precision rate and recall rate of micro-averaging/macro-averaging were 0.75/0.73 and 0.75/0.72. If we took a newly carved tooth picture into the program, the current effectiveness of machine learning was about 70%-75% to evaluate the quality of tooth morphology. Through the calculation and analysis of the two different concepts of micro-average/macro-average and AUC, similar values could be obtained. Conclusion: This study established a set of procedures that can judge the quality of hand-carved plaster sticks and teeth, and the accuracy rate is about 70%-75%. It is expected that this process can be used to assist dental technicians in judging the pros and cons of hand-carved plaster sticks and teeth, so as to help dental technicians to learn the tooth morphology more effectively.

Development of a zinc chloride-based chemo-mechanical system for potential minimally invasive dental caries removal system.

Background/purpose: The chemo-mechanical caries-removal technique is known to offer advantages of selective dentin caries treatment while leaving healthy dental tissues intact. However, current sodium hypochlorite based reagents usually excessively damage dentin collagen. Therefore, the purpose of this study was to develop a novel chemo-mechanical caries-removal system to preserve the collagen network for subsequent prosthetic restorations. Materials and methods: The calfskin-derived collagen was chosen as a model system to investigate the dissolution behavior of collagen under different operating conditions of chemical-ultrasonic treatment systems. The molecular weight, triple-helix structure, the morphology, and functional group of collagen after treatment were investigated. Results: Various concentrations of sodium hypochlorite or zinc chloride together with ultrasonic machinery were chosen to investigate. The outcomes of circular dichroism (CD) spectra demonstrated stability of the triple-helix structure after treatment of a zinc chloride solution. In addition, two apparent bands at molecular weights (MWs) of 130 and 121 kDa evidenced the stability of collagen network. The positive 222 nm and 195 nm negative CD absorption band indicated the existence of a triple-helix structure for type I collagen. The preservation of the morphology and functional group of the collagen network on the etched dentin surface were investigated by in vitro dentin decalcification model. Conclusion: Unlike NaOCl, the 5 wt% zinc chloride solution combined with ultra-sonication showed dissolution rather than denature as well as degradation of the dentin collagen network. Additional in vivo evaluations are needed to verify its usefulness in clinical applications.

Investigation of mechanical properties and low-temperature degradation of dental 3Y-TZP ceramics fabricated by stereolithography in combination with microwave sintering.

The purpose of this study was to obtain dental ceramic materials with excellent mechanical properties and high resistance to low temperature degradation (LTD) via stereolithography (SLA) in combination with microwave sintering (MWS). The results have shown that the unaged MWS-1425 °C 3Y-TZP ceramics with uniform microstructure have high density up to 99.04% and excellent mechanical properties (Vickers hardness 14.07 GPa, fracture toughness 4.32 MPa m1/2, flexural strength 947.87 MPa). After 50 h of LTD, the m-phase content of MWS 3Y-TZP ceramics accounts for only 10.3%. In addition, the surface roughness increases by only 1.3 nm, the degraded depth is less than 5 µm, and the flexural strength exceeds 900 MPa. This exhibits the high resistance to LTD and excellent mechanical properties of dental 3Y-TZP ceramics can be obtained.

Development of biodegradable nanogels for lipase accelerated drug release of 5-aminolevulinic acid.

Photodynamic therapy (PDT) using 5-aminolevulinic acid (5-ALA) is an important approach for the treatment of some skin diseases and cancers. A major defect of this approach is that it is difficult for 5-ALA to accumulate around lesions in deeper regions of tissue, resulting in poor conversion to the active fluorophore and photodynamic efficiencies. Because of their targeting and controlled release abilities, nanogel carriers could solve this problem. In this paper, nanogels were prepared by using micro-emulsion polymerization with various biodegradable polyester crosslinkers (L-lactide and ε-caprolactone). The swelling and degradation properties and entrapment efficiency, drug loading and drug release ability of the nanogels were investigated. Nanogels co-cultured with skin cancer cells (A2058) allowed the efficiency of the PDT in vitro to be demonstrated. The results showed that the swelling rate of hydrogels reduced with increasing crosslinker levels, which caused a slow-down in the release of 5-ALA, but lipase accelerated degradation of nanogels increased 5-ALA concentrations in tumor cells and leading to higher PDT efficiency. It was proved by in vivo experiment indicating that the development of skin cancer tissues were efficiently inhibited by the 5-ALA loaded nanogels.

Surface modification of zirconia ceramics through cold plasma treatment and the graft polymerization of biomolecules.

Background/purpose: Although zirconia ceramics were highly versatile as dental implants, their long-term presence in the human body may slow down healing and impede cell growth in the past. To enhance the cytocompatibility of zirconia ceramics, surface activation modification was used to immobilize biopolymers such that a biomimetic environment was created. Materials and methods: Hexamethyldisilazane thin films were deposited onto the surface of inorganic zirconia through cold plasma treatment under various power and deposition time settings to form an organosilane interface layer. Next, oxygen plasma treatment was performed to activate the free radicals on the surface. Subsequently, ultraviolet light was employed to graft and polymerize acrylic acid for generating carboxyl groups on the surface. This was followed by a condensation reaction with biopolymers (chitosan, chitosan/poly-γ-glutamic acid, and gelatin). Results: Under a 20-min deposition time at 40 W and 150 mTorr, the thin films had a maximum graft density of 2.1 mg/cm2. MG-63 cells (human osteosarcoma cells) were employed to evaluate cell compatibility. Chitosan and chitosan/poly-γ-glutamic acid promoted the compatibility of MG-63 cells (a human osteosarcoma cell line) with zirconia ceramics, whereas gelatin reduced this compatibility. Conclusion: The findings confirm that cold plasma treatment and graft polymerization can promote the immobilization of biomolecules and improve the biocompatibility of zirconia ceramics. This approach can be applied to the modification of zirconia ceramic implants.

Comparative analysis of bonding strength between enamel and overlay of varying thicknesses following an aging test.

Abstract: Background/purpose: Overlay restorations can be used clinically as a treatment option to preserve natural dentine. However, whether the residual enamel thickness and overlay thickness affect the adhesion between the restoration and tooth is still unknown. This study was to investigate effects of the overlay thickness and residual enamel thickness on bonding strength. Materials and methods: Overlays of different thicknesses were prepared with natural teeth which had 2, 4, and 6 mm of occlusal reduction (n = 10). Specimens were subjected to 10,000 cycles in water at 5-55 °C, and finally compressive strength tests were used to evaluate the bonding strength. Results: All groups showed good bond strength (P > 0.05). The overlay restorations of different thicknesses reduced the preparation amount by 30.3%-7.2% and significantly preserved more of the tooth structure (P < 0.005). Compared to the control group, the overlay restoration increased the marginal fitness by about 0.67-0.88 times. The thermal cycling indicated that the decrease in the maximum bearing stress was due to the aging of the ceramic itself. Therefore, the thickness of the overlay had a greater influence on the compressive strength than the bond strength. Conclusion: Based on the above this study recommends an overlay thickness of at least 2 mm in clinical practice. The aging test confirmed that adhesion between the overlay and teeth was quite firm and stable. This shows that a stable adhesive effect of the overlay can be used as a treatment option for preserving a greater amount of a tooth's structure.

Recurrence of Local Kyphosis After Percutaneous Kyphoplasty: The Neglected Injury of the Disc-Endplate Complex.

Background: Recurrent of local kyphosis after percutaneous kyphoplasty (PKP) is rarely reported and discussed. Literatures reported that re-kyphosis is usually a consequence of refractures of augmented or adjacent vertebra. However, whether re-kyphosis should be considered as a complication of refractures and has an impact on clinical efficacy of PKP during follow-up time is unknown. The purpose of this study is to evaluate the related risk factors and clinical significance of the recurrent of local kyphosis in osteoporotic vertebral fracture (OVF) patients without refractures. Patients and Methods: A total of 143 patients who underwent single-level PKP were recruited and assigned into the re-kyphosis group and non-re-kyphosis group. Clinical and radiographic data were collected and compared between the two groups. Then, multivariate logistic regression analyses were conducted to identify the related risk factors. Results: During follow-up, 16 of the 143 patients presented postoperative re-kyphosis. The average local kyphosis angle increased from 11.81±8.60° postoperatively to 25.13±8.91° at the final follow-up which showed a statistically significant difference (p<0.05). Both groups had significant improvements in postoperative visual analogue scale (VAS) and Oswestry Disability Index (ODI) scores compared to their preoperative values (p<0.05). However, in the re-kyphosis group at final follow-up, the VAS and ODI scores showed worsening compared to the postoperative scores. Logistic regression analysis showed that disc-endplate complex injury (OR=17.46, p=0.003); local kyphosis angle correction (OR=1.84, p<0.001); and vertebral height restoration (OR=1.15, p=0.003) were risk factors for re-kyphosis. Conclusion: Re-kyphosis is not rare in patients with osteoporotic vertebral fracture and tends to have an inferior prognosis following PKP surgery. Patients with disc-endplate complex injury and more correction of vertebral height and kyphosis angle are at a higher risk for re-kyphosis after PKP surgery than others.