Isoginkgetin-loaded reactive oxygen species scavenging nanoparticles ameliorate intervertebral disc degeneration via enhancing autophagy in nucleus pulposus cells.

Excessive reactive oxygen species (ROS) in nucleus pulposus cells (NPCs) promote extracellular matrix (ECM) degradation and cellular inflammatory responses by activating a variety of cellular pathways, ultimately inducing cell apoptosis and leading to the development of low back pain. Here, we designed and fabricated an isoginkgetin-loaded ROS-responsive delivery system (IGK@SeNP) based on diselenide block copolymers. Successfully encapsulated IGK was released intelligently and rapidly in a microenvironment with high ROS levels in degenerative disc. Controlled-release IGK not only efficiently scavenged ROS from the intervertebral disc together with diselenide block copolymers but also effectively enhanced autophagy in NPCs to inhibit ECM degradation and cell apoptosis, and showed significant therapeutic effects in the rat intervertebral disc degeneration (IDD) model. Overall, the synergistic effects of IGK@SeNP in ROS scavenging and autophagy enhancement endowed it with an attractive therapeutic strategy for IDD treatment.

Thoracolumbar fascia injury in osteoporotic vertebral fracture: the important concomitant damage.

BACKGROUND: Thoracolumbar fascia injury (FI) is rarely discussed in osteoporotic vertebral fracture (OVF) patients in previous literature and it is usually neglected and treated as an unmeaning phenomenon. We aimed to evaluate the characteristics of the thoracolumbar fascia injury and further discuss its clinical significance in the treatment of kyphoplasty for osteoporotic vertebral fracture (OVF) patients. METHODS: Based on the presence or absence of FI, 223 OVF patients were divided into two groups. The demographics of patients with and without FI were compared. The visual analogue scale and Oswestry disability index scores were compared preoperatively and after PKP treatment between these groups. RESULTS: Thoracolumbar fascia injuries were observed in 27.8% of patients. Most FI showed a multi-level distribution pattern which involved a mean of 3.3 levels. Location of fractures, severity of fractures and severity of trauma were significantly different between patients with and without FI. In further comparison, severity of trauma was significantly different between patients with severe and non-severe FI. In patients with FI, VAS and ODI scores of 3 days and 1 month after PKP treatment were significantly worse compared to those without FI. It showed the same trend in VAS and ODI scores in patients with severe FI when compared to those patients with non-severe FI. CONCLUSIONS: FI is not rare in OVF patients and presents multiple levels of involvement. The more serious trauma suffered, the more severe thoracolumbar fascia injury presented. The presence of FI which was related to residual acute back pain significantly affected the effectiveness of PKP in treating OVFs. TRIAL REGISTRATION: retrospectively registered.

Neural Network-Based Adaptive Height Tracking Control of Active Air Suspension System with Magnetorheological Fluid Damper Subject to Uncertain Mass and Input Delay.

In this paper, we present a novel robust adaptive neural network-based control framework to address the ride height tracking control problem of active air suspension systems with magnetorheological fluid damper (MRD-AAS) subject to uncertain mass and time-varying input delay. First, a radial basis function neural network (RBFNN) approximator is designed to compensate for unmodeled dynamics of the MRD. Then, a projector-based estimator is developed to estimate uncertain parameter variation (sprung mass). Additionally, to deal with the effect of input delay, a time-delay compensator is integrated in the adaptive control law to enhance the transient response of MRD-AAS system. By introducing a Lyapunov-Krasovskii (LK) functional, both ride height tracking and estimator errors can robustly converge towards the neighborhood of the desired values, achieving uniform ultimate boundness. Finally, comparative simulation results based on a dynamic co-simulator built in AMESim 2021.2 and Matlab/Simulink 2019(b) are given to illustrate the validity of the proposed control framework, showing its effectiveness to operate ride height regulation with MRD-AAS systems accurately and reliably under random road excitations.

Mechanical properties of bulk-fill resin composites with single increment up to 4 mm: A novel mechanical strength test.

PURPOSE: To evaluate the mechanical properties of two brands of bulk-fill resin composites placed in a single increment up to 4 mm thickness via a novel mechanical strength test and provide related explanations. METHODS: Light transmission (LT), translucency parameter (TP), color difference (ΔE), Vickers hardness (HV) of two bulk-fill resin composites (Filtek Bulk Fill Posterior, Tetric N-Ceram Bulk Fill) and two conventional resin composites (Z100, Spectrum TPH) were evaluated. A novel flexural strength (FS) test method was applied for bulk-fill resin composite to determine the FS value of the bottom composites at depths of 1, 2, 3, and 4 mm after 24 hours of aging treatment (3 months water storage and 15,000 thermal cycles). The conventional resin composites were also tested for FS and all the FS results were subjected to Weibull analysis. Degree of conversion (DC) in the bulk-fill resin composites, light-cured at depths of 1, 2, 3, and 4 mm and conventional resin composites at depths of 2 and 4 mm, were assessed by FTIR. RESULTS: Both bulk-fill resin composites showed higher light transmission and translucency than that of conventional ones at each of the same thicknesses (1, 2, 3, 4 mm), wherein their flexural strength was not affected by depth. The Weibull analysis suggested both bulk-fill resin composites achieved good reliability and structural integrity under each curing thickness. Vickers hardness was affected by the material type and thickness. Bulk-fill resin composites showed a decrease in degree of conversion between 1 mm and 4 mm, but both were over 55%. CLINICAL SIGNIFICANCE: Filtek Bulk Fill Posterior, Tetric N-Ceram Bulk Fill achieved acceptable mechanical properties when cured at depths of up to 4 mm, which was beneficial from their optical and polymerized properties.

Evaluation of custom posts and cores fabricated by two digital technologies in core and post space dimensions.

PURPOSE: To evaluate the adaptability between posts and post spaces and the rationality of cores fabricated by two digital custom post-and-core processes. MATERIALS AND METHODS: Titanium post-and-cores were fabricated by digital scanning impression technology or digital scanning wax-pattern technology on tooth defect molds of incisors, premolars, and molars, with traditional lost-wax casts of these teeth as the controls. Micro-CT and a laboratory scanner were used to determine intervals between post wall and root canal wall of the root apex, middle, and cervix of each sample in cross-, sagittal, and coronal sections; intervals between the end of post and tooth; diameters of cervical, middle, and incisal part at cross-, sagittal, and coronal sections of each sample, as well as shoulder widths. RESULTS: The three fabrication processes showed significant differences in intervals between post-and-core prostheses and root canal walls, diameters of all parts of cores, and shoulder widths. Scanning impressions showed significant advantages in the main part of post-and-cores in incisors and premolars, while the scanning wax-pattern process showed obvious inferiorities in premolars and molars. As to core spatial size, values of measured sites in the scanning impression process were closer to the standard than those of the traditional process, while differences between the measured value of the scanning wax-pattern process were much more obvious than in the traditional process. CONCLUSIONS: The use of digital custom post-and-core scanning impressions improved the rationality and precision of post-and-core dimensions compared with two other processes.

Comparison of stress distribution between zirconia/alloy endocrown and CAD/CAM multi-piece zirconia post-crown: three-dimensional finite element analysis.

OBJECTIVES: This study aimed to evaluate a digital multi-piece zirconia post-crown to restore a mandibular second molar with extensive coronal loss and limited restoration space, and to compare the stress distribution between endocrowns made of zirconia or alloy and CAD/CAM multi-piece zirconia post-crowns. MATERIAL AND METHODS: Four three-dimensional finite element analysis models of a mandibular second molar with extensive coronal loss and limited restoration space were created as follows: (A) intact molar; (B) zirconia endocrown restored molar; (C) multi-piece post-crown restored-molar with tapered nail; (D) multi-piece post-crown restored molar with T-shaped nail. Models C and D were divided into two subgroups according to the material type: C1/D1, zirconia; C2/D2, NiCr alloy. The maximum modified von Mises failure criterion (mvM) stresses were calculated, and the stress distribution was recorded to analyze the effects of the restoration and material types on the biomechanical properties of dentin and prosthesis. RESULTS: The maximum mvM stress of dentin in model B (33.80 MPa) was lower compared with models C (C1, 37.81 MPa; C2, 36.36 MPa) and D (D1, 36.34 MPa; D2, 34.97 MPa) under vertical load, but the opposite was observed under oblique load. The highest mvM stress was concentrated in the nail region located in the root canal, and the T-shaped nail values were greater than the tapered nail, whereas model D with T-shaped nail showed a lower mvM stress level in dentin compared with Model C with tapered nail. CONCLUSIONS: The digital multi-piece zirconia post-crown is a potential approach to restore mandibular second molars with extensive coronal loss and limited restoration space. CLINICAL RELEVANCE: The digital multi-piece zirconia post-crown has potential to restore mandibular second molars with extensive coronal loss and limited restoration space using an innovative approach.

In vitro comparison of bonding to zirconia- or glass- based ceramics between flowable resin composites and composite resin cements.

PURPOSE: To evaluate and compare the bonding of flowable resin composites and light-cured resin cements to dental ceramics. METHODS: Grit-blasted zirconia plates were primed with MDP-containing adhesive. Lithium disilicate glasses plates were etched with HF and primed with silane. Two flowable resin composites with high (CM: 75 wt%/62 vol%) and low (BF: 67.3 wt%/47 vol%) filler contents, and two resin cements, again with high (C: 72 wt%/69 vol%) and low (R: 66 wt%/47 vol%) filler contents, were bonded to both types of pretreated ceramics. Shear bond strength (SBS) was measured after 24 hours water storage or 10,000 times thermocycling between 5 and 55°C. The viscosities and film thicknesses of the four resin-based luting agents (RBLAs) were also explored by rotational rheometer and metallurgical microscope severally. RESULTS: Different RBLAs provided statistically different SBS values, with the high-filler specimens exhibiting higher SBS values than the low-filler specimens. The viscosities decreased in the order C > R > BF > CM. The film thicknesses for the BF and C groups were higher than those of the CM and R groups. CLINICAL SIGNIFICANCE: This study provides evidence that flowable resin composites with high filler contents and low viscosities may serve as an alternative to light-cured resin cements for luting zirconia or lithium disilicate glass. This expands the range of light-cured luting agents available for bonding of veneers or other thin restorations, which is of great benefit to clinical practice.

Evaluation of intraoral optical scanning accuracy for fine structure reconstruction and occlusal records of inlay/onlay preparations.

AIM: The present study aimed to determine the impact of different degrees of salivary contamination and variations in occlusal force during intraoral scanning of inlay/onlay cavities on the accuracy of fine structure reconstruction and occlusal records. MATERIALS AND METHODS: Digital data of inlay/onlay models, collected using an intraoral scanner, were divided into 40 groups according to the restoration type (onlay or inlay), salivary contamination level (none, completely dry; mild, moist but not visually completely apparent; moderate, half-filled cavity; severe, filled-up cavity), and simulated occlusal force (0, 2, 4, 6 or 8 kg). The acquired 120 datasets were used to measure the average interocclusal space and cavity buccolingual internal angle. RESULTS: Salivary contamination and occlusal force did affect the occlusal contact (P < 0.001), but restoration type did not (P > 0.05). An interaction was found between inlay type and salivary contamination (P < 0.001), but not between occlusal force and salivary contamination (P > 0.05). Salivary contamination also affected the accuracy of fine structure reconstruction (P < 0.001), but restoration type did not (P > 0.05), and no interaction was found between the two factors (P > 0.05). The difference in the measured internal angle increased with the increase in salivary contamination. CONCLUSIONS: Intraoral optical scanning of inlay/onlay preparations was reliable for recording occlusal contact but showed uncertainty in cavity fine structure reconstruction when moderate or severe salivary contamination was present in the cavity. Nevertheless, a moist cavity surface with no visually apparent salivary contamination is acceptable. (Int J Comput Dent 2022;25(3):257-265; doi: 10.3290/j.ijcd.b2599691).

Exposure to PM2.5 during pregnancy causes lung inflammation in the offspring: Mechanism of action of mogrosides.

Epidemiological and toxicological studies have demonstrated that exposure to fine particulate matter (PM2.5) during pregnancy is harmful to the tissues of the offspring. However, the mechanism by which PM2.5 exposure causes lung damage in the offspring or potential dietary therapy for this condition remains unclear. Mogrosides (MGs) are derived from the traditional plant Siraitia grosvenorii and are used medicinally, where they can moisten the lungs and relieve coughing. In this study, pregnant rats were exposed to PM2.5 by intratracheal instillation and treated with MGs by gavage to model the effect of PM2.5 in the offspring and the interventional effect of MGs on lung tissue. We then used transcriptomics, metabolomics, and RT-qPCR as tools to look for metabolite and genetic changes in the offspring. We found that when compared to the control group, the mRNA levels of the inflammatory mediator Pla2g2d and the metabolites lysophosphatidylcholines (LysoPCs) and arachidonic acid (AA) were up-regulated in the lung tissues of PM2.5 group. In contrast, these inflammatory changes were restored after treatment with MGs during pregnancy. In addition, the levels of AA, LPC 15:0 and LPC 18:0 were elevated in the PM2.5 group compared with control group. This increase was inhibited by co-administration of MGs. The change of PGA1 was adverse. In conclusion, even a relatively low exposure to PM2.5 in rats during pregnancy produces inflammation in the lungs of the male offspring, and an intervention with MGs could significantly alleviate this effect. Furthermore, Pla2g2d may represent a potential target for MGs resulting in the improvement of PM2.5-induced lung injury.

Comparison of 3 Treatment Methods for Distal Tibial Fractures: A Network Meta-Analysis.

BACKGROUND The choice of optimal internal fixation device for distal tibial fractures remains controversial. The purpose of our study was to evaluate the effectiveness and safety of open reduction and internal fixation, minimally invasive percutaneous osteosynthesis, and intramedullary nailing of distal tibial fractures in adults using network meta-analysis of data from clinical trials. MATERIAL AND METHODS The studies were abstracted from MEDLINE, EMBASE, CNKI, and the Cochrane Central Register of Controlled Trials. Randomized controlled trials meeting inclusion and exclusion criteria were selected. Statistical analyses were conducted using Stata software, version 13.0 (Stata Corporation, College Station, Texas, USA). RESULTS Eleven randomized controlled trials were included. The total number of participants was 710 and the studies were published between 2005 and 2017. There were no significant differences in rates of delayed union, nonunion, or malunion among the various treatments (all p>0.05). The intramedullary nailing group had a lower incidence of wound complications than did the open reduction and internal fixation group and minimally invasive percutaneous osteosynthesis technique group. The SUCRA probabilities were 28.6% for ORIF, 98.4% for IMN, and 22.9% for MIPPO. CONCLUSIONS Given the superior results for intramedullary nailing in terms of wound complications, we recommend this procedure for treatment of distal tibial fractures. More RCTs focused on distal tibial fractures are needed to support the current evidence.

Durability of Resin Bonding to Zirconia Using Products Containing 10-Methacryloyloxydecyl Dihydrogen Phosphate.

PURPOSE: To examine the durability of composite bonding to zirconia after artificial aging using different products containing 10-methacryloyloxydecyl dihydrogen phosphate (MDP). MATERIALS AND METHODS: Conditioning methods were: none (control [Ctr]; Clearfil SA Luting [CSL]; Panavia SA Luting Plus [PSLP]), MDP-containing zirconia primers (Z-Prime Plus [ZP]; Clearfil Ceramic Primer [CCP]), and MDP-containing universal adhesives (Single Bond Universal [SBU]; Clearfil Universal Bond [CUB]). For the Ctr, ZP, CCP, SBU, and CUB groups, the Y-TZP plates were bonded with MDP-free composite cement. For the remaining two groups, each Y-TZP plate was bonded with one of MDP-containing self-adhesive composite cements (CSL; PSLP). The specimens in each group (n = 30) were divided into two subgroups, with one subgroup of samples subjected to 24-h water storage and the other to aging through 30,000 thermocycles plus 180-day water storage. Shear bond strength (SBS) was measured. For each conditioning method, inductively coupled plasma-mass spectrometry (ICP-MS) was used to quantify the release of phosphorus, and microleakage was evaluated through a methylene-blue dyeing technique. RESULTS: The Ctr group exhibited the lowest SBS regardless of aging. Thermocycling and water storage significantly decreased the SBS in all groups, with the exception of the groups with the MDP-containing zirconia primers. Groups with MDP-containing universal adhesives and self-adhesive composite cements presented brand-dependent higher SBS, even after aging. ICP-MS detected phosphorus release from all of the MDP-containing products. Microleakage was identified at the interfaces of all bonded specimens, with the highest rate detected in the Ctr group. CONCLUSION: MDP-containing primers, universal adhesives, and composite cements create bonds to zirconia with acceptable strength after long-term aging.

Effects of Luting Cements and Surface Conditioning on Composite Bonding Performance to Zirconia.

PURPOSE: This study compared bond strength, durability, and mechanical properties of luting cements for bonding zirconia: a resin-modified glass ionomer cement (RMGIC), a conventional composite cement, and two self-adhesive composite cements. MATERIALS AND METHODS: The air-abraded zirconia specimens were assigned to 12 groups (n = 30) to prepare bonded specimens. Classification was based on the pre-conditioning selection: none; primers containing 10-methacryloyloxydecyl dihydrogen phosphate (MDP); universal adhesives containing MDP. Further classification was done according to the type of luting cement: RMGIC; conventional composite cement; MDP-free self-adhesive composite cement; MDP-containing self-adhesive composite cement. The shear bond strength (SBS) was measured after 24 h of water storage or aging with 20,000 thermocycles plus an additional 60 days of water storage at 37°C. The elastic modulus and three-point bending strength were determined, and a related Weibull analysis of the four luting cements was performed. RESULTS: The choice of luting cement and aging significantly affected the SBS. Aging decreased the SBS in most groups, except for those that used MDP-containing primers plus conventional composite cements. RMGIC had SBS (before and after aging) that were similar to the MDP-free self-adhesive composite cement. Use of MDP-containing products prior to conventional composite cements provided the highest initial SBS. However, pre-conditioning with MDP-containing products failed to increase the SBS of RMGIC. RMGIC showed lower elastic modulus and three-point bending strength than did the three composite cements. CONCLUSIONS: RMGIC is an alternative to composite cements for luting zirconia restorations. Conditioning with a primer containing MDP combined with conventional composite cement is more reliable.

Mogroside IIIE, a Novel Anti-Fibrotic Compound, Reduces Pulmonary Fibrosis through Toll-Like Receptor 4 Pathways.

Idiopathic pulmonary fibrosis is a progressive fibrotic lung disease, and eventually most patients develop respiratory failure with a median survival rate of 2 to 3 years after diagnosis due to the lack of clinically effective therapies. Mogroside IIIE (MGIIIE), a cucurbitane-type compound, was isolated from Siraitia grosvenorii MGIIIE has shown the strongest inhibition of nitric oxide release, a crucial inflammatory factor, from lipopolysaccharide (LPS)-treated RAW264.7 cells compared with other mogrosides. In the pulmonary fibrosis mouse model induced by bleomycin, MGIIIE treatment attenuated pulmonary fibrosis, indicated as a reduction in myeloperoxidase activity, collagen deposition, and pathologic score. MGIIIE also significantly suppressed expression of several important fibrotic markers, e.g., α-smooth muscle actin, collagen I, transforming growth factor-ß (TGF-ß) signal, and metalloproteinases-9/tissue inhibitor of metalloproteinase-1. Furthermore, MGIIIE blocked tansdifferentiation of lung resident fibroblasts into myofibroblast-like cells induced by TGF-ß or LPS and subsequently inhibited collagen production in lung fibroblasts. These data indicate that MGIIIE is a potent inhibitor for pulmonary fibrosis. In vitro and in vivo mechanistic studies have shown that MGIIIE significantly decreased expression of toll-like receptor 4 (TLR4) and its downstream signals of myeloid differentiation factor 88 (MyD88)/mitogen-activated protein kinase (MAPK), an inflammatory signal essential for extracellular matrix (ECM) deposition in pulmonary fibroblasts. Taken together, these results demonstrate that MGIIIE significantly prevents pulmonary fibrosis by inhibiting pulmonary inflammation and ECM deposition through regulating TLR4/MyD88-MAPK signaling. Our study suggests that MGIIIE may have therapeutic potential for treating pulmonary fibrosis in clinical settings.

Mogroside IIIE Attenuates LPS-Induced Acute Lung Injury in Mice Partly Through Regulation of the TLR4/MAPK/NF-κB Axis via AMPK Activation.

Acute lung injury (ALI) often leads to high mortality, and there is as yet no effective drug treatment. The present study aimed to investigate protective effects of mogroside IIIE (MGIIIE, a cucurbitane-type triterpenoid from Siraitia grosvenorii Fruits) in experimental ALI and its underlying mechanism. MGIIIE (1, 10 0r 20 mg/kg) was orally administered for 1 h before a single intratracheal administration of lipopolysaccharide (LPS, 5 mg/kg). MGIIIE treatment dose-dependently suppressed pulmonary oedema, pro-inflammatory mediators (IL-1ß, IL-6, TNF-α and HMGB1) release and higher MPO activity in lung tissues induced by LPS challenge. Molecular researches showed that mogroside IIIE (20 mg/kg) not only increased the phosphorylation of adenosine 5'-monophosphate-activated protein kinase (AMPK) but suppressed the over-expression of toll-like receptor 4 (TLR4) and myeloid differentiation factor 88 (MyD88). In addition, MGIIIE also inhibited the activation of MAPKs and nuclear factor κB (NF-κB) signalling in lung tissues from LPS-challenged mice. Similar antiinflammatory effects of MGIIIE were obtained in LPS-treated macrophages. Compound C (a pharmacological AMPK inhibitor) obviously reversed the antiinflammatory effect of MGIIIE in LPS-induced ALI mice. Taken together, AMPK activation plays a crucial role in the antiinflammatory effects of MGIIIE in LPS-induced ALI by down-regulating TLR4/MAPK/NF-κB signalling pathways. Copyright © 2017 John Wiley & Sons, Ltd.

Effect of 10-Methacryloxydecyl Dihydrogen Phosphate Concentration on Chemical Coupling of Methacrylate Resin to Yttria-stabilized Zirconia.

PURPOSE: To test the hypothesis that the concentration of 10-methacryloxydecyl dihydrogen phosphate (MDP) in zirconia primers has no effect on the chemical bonding efficacy of methacrylate resins to yttria-stabilized tetragonal zirconia (Y-TZP). MATERIALS AND METHODS: Shear bond strength testing was performed to evaluate the efficacy of experimental primers containing 5, 10, 15, 20 or 30 wt% MDP (5M, 10M, 15M, 20M, 30M) in improving composite-zirconia bond strength. Bonding without use of MDP-containing primer served as the negative control (Ctr0). Bonding with a commercially available MDP-containing primer served as the positive control (CtrM). Thermogravimetric analysis (TGA), inductively coupled plasma-mass spectrometry (ICP-MS), x-ray photoelectron spectroscopy (XPS), Fourier transform-infrared spectroscopy (FT-IR), and computational simulation of infrared spectra were used to confirm the formation of Zr-O-P bond between MDP and Y-TZP. RESULTS: Results derived from TGA, ICP-MS, XPS, and FT-IR suggested that MDP chemically bonded with Y-TZP. Simulation of IR data supported the FT-IR results. There was a higher concentration of phosphorus on the 10M-conditioned Y-TZP surface when compared with the other groups, suggesting bettter formation of Zr-O-P bond in the 10M group. Shear bond strengths were significantly lower for group 5M (p < 0.05), compared to groups 10M to 30M, which were not significantly different from one another (p > 0.05). CONCLUSIONS: MDP improves resin bonding of zirconia through the formation of Zr-O-P bonds with zirconia. 10 wt% MDP appears to be the most optimal concentration for synthesizing zirconia primers for resin bonding.

Improvement in the Bonding of Y-TZP by Room-temperature Ultrasonic HF Etching.

PURPOSE: To investigate the effects of room-temperature etching with hydrofluoric acid (HF) in the presence and absence of ultrasonic irradiation on the bonding of yttria-stabilized tetragonal zirconia polycrystals (Y-TZP) to resin. MATERIALS AND METHODS: Y-TZP specimens were etched with 40% HF at room temperature for different time periods (2, 5, 10, 15, 30, 60, and 90 min) with and without ultrasonic exposure. The surface roughness, micromorphology, dimensions, and phases of the treated Y-TZP specimens were evaluated by atomic force microscopy (AFM), scanning electron microscopy (SEM), digital caliper measurement, and x-ray diffraction, respectively. The HF etching conditions that resulted in the most drastic Y-TZP surface morphology and highest roughness values were used to prepare specimens for shear bond strength (SBS) testing; the effect of thermocycling on SBS was also examined. Alumina-sandblasted Y-TZP specimens were used as the control. RESULTS: The Y-TZP surfaces etched with HF without ultrasonic exposure for 30, 60, and 90 min and those surfaces ultrasonically etched with HF for 10 and 15 min were severely etched, although their dimensions were not changed by etching. Monoclinic-phase zirconia was observed only in the alumina-sandblasted Y-TZP specimens. Surface roughening from HF etching for 30 min and ultrasonic etching for 10 min resulted in higher mean SBS compared to roughening with alumina sandblasting. CONCLUSION: Ultrasonic etching with 40% HF at room temperature for 10 min may be used as an alternative roughening method for improving the bonding of Y-TZP.

(±)-Homocrepidine A, a Pair of Anti-inflammatory Enantiomeric Octahydroindolizine Alkaloid Dimers from Dendrobium crepidatum.

A pair of racemic indolizidine enantiomers, (±)-homocrepidine A (1), and a piperidine derivative, homocrepidine B (2), were isolated from Dendrobium crepidatum along with the known alkaloid crepidine (3). The racemic mixture of 1 was separated into a pair of enantiomers, (+)-1 and (-)-1, by HPLC using a chiral chromatographic substrate, which represents the first successful example of resolving indolizidine racemic mixtures. The absolute configurations of (+)-1 and (-)-1 were assigned from single-crystal X-ray diffraction data. The evaluation of anti-inflammatory activity with LPS-induced RAW 264.7 macrophages revealed that (+)-1 strongly inhibited the production of nitric oxide (IC50, 3.6 µM) and significantly decreased the expression of inducible nitric oxide synthase, while (-)-1 and (±)-1 only had moderate inhibitory effects (IC50, 22.8 and 14.7 µM). Compound 2 showed moderate anti-inflammatory activity (IC50, 27.6 µM).

Effects of multiple firings on the low-temperature degradation of dental yttria-stabilized tetragonal zirconia.

STATEMENT OF PROBLEM: The clinical failure of yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) substrates may be attributed to their susceptibility to low-temperature degradation (LTD). The acceleration of LTD by multiple veneering firings of Y-TZP remains poorly understood. PURPOSE: The purpose of this in vitro study was to evaluate the effects of different numbers of veneering firing cycles on the LTD of Y-TZP. MATERIAL AND METHODS: Ninety bar-shaped specimens were cut from a machinable Y-TZP block and fully sintered. The Y-TZP bars were divided into 3 groups; each group received 1, 3, or 5 veneering porcelain firing cycles. Specimens from each firing cycle (n=10) were then subjected to hydrothermal aging in an autoclave sterilizer for 10 or 20 hours to accelerate the LTD of Y-TZP. Specimens without hydrothermal aging served as the control. XRD was used to characterize phase transformations. The flexural strength and surface Vickers hardness of the 9 subgroups were investigated, and scanning electron microscopy was used to characterize the fractured surface morphology. RESULTS: Hydrothermal aging increased the monoclinic phase, although increased hydrothermal aging time provided no additional effects. Veneering firings did not enhance the influence of hydrothermal aging on phase transformation. No statistical significance was found among the 9 groups in terms of flexural strength or surface Vickers hardness (P>.05). CONCLUSIONS: Additional veneering porcelain firing cycles do not accelerate the LTD of Y-TZP.

One-step synthesis of diazaspiro[4.5]decane scaffolds with exocyclic double bonds.

Unactivated yne-en-ynes reacted with a range of substituted aryl halides in the presence of Pd(OAc)2-PPh3 to afford diazaspiro[4.5]decane with exocyclic double bonds. Three carbon-carbon bonds are formed in this domino reaction, which involves highly regioselective C-C coupling and spiro scaffold steps.

Evaluation of a commercial primer for bonding of zirconia to two different resin composite cements.

PURPOSE: To evaluate the effects of a commercial zirconia primer (Choice or RelyX Unicem) on shear bond strength (SBS) of two different resin composite cements - Choice (a conventional bis-GMA-based resin cement) and RelyX Unicem (self-adhesive resin cement) - to zirconia. MATERIALS AND METHODS: Zirconia blocks were manufactured and randomly divided into 5 main groups (n = 20) that received surface treatments and cements as follows: no surface treatment, Choice and RelyX Unicem (groups C and U, resp.); tribochemical silica coating followed by silanization, Choice (group SSC); application of a zirconia primer, Choice and RelyX Unicem (groups ZC and ZU, resp.). Light-curing composite resin cylinders were prepared and bonded on the prepared zirconia blocks using the two different resin cements. Half of the specimens in each group were stored in water for 24 h, and half were aged by 50 days of water storage followed by thermocycling (12,000 cycles between 5°C and 55°C). Thereafter, all of them were submitted to the SBS test. Fourier transmission infrared (FT-IR) spectrum analysis and gas mass spectrometry (MS) analysis were adopted for characterization of the zirconia primer. RESULTS: Statistical analysis of the SBS test showed that group C presented the lowest SBS values and group SSC the highest (p < 0.01). Artificial aging exerted no influence on the SBS of groups U, SSC, ZC, or ZU. FT-IR analysis suggested that benzene rings and carboxylic groups exist in the zirconia primer. MS analysis detected that 2-hydroxyethyl methacrylate, triethylamine, ethyl-4-dimethylaminobenzoate, ethanol, and water are contained in the primer. CONCLUSION: The zirconia primer and self-adhesive resin cement increased the SBS of zirconia.