MTDH-stabilized DDX17 promotes tumor initiation and progression through interacting with YB1 to induce EGFR transcription in Hepatocellular Carcinoma.

Metadherin (MTDH) is a well-established oncogene in various cancers including Hepatocellular Carcinoma (HCC). However, the precise mechanism through which MTDH promotes cancer-related signaling pathways in HCC remains unknown. In this study, we identified DDX17 as a novel binding partner of MTDH. Furthermore, MTDH increased the protein level of DDX17 by inhibiting its ubiquitination. We confirmed that DDX17 was a novel oncogene, with dramatically upregulated expression in HCC tissues. The increased expression of DDX17 was closely associated with vascular invasion, TNM stage, BCLC stage, and poor prognosis. In vitro and in vivo tests demonstrated that DDX17, a downstream target of MTDH, played a crucial role in tumor initiation and progression. Mechanistically, DDX17 acted as a transcriptional regulator that interacted with Y-box binding protein 1 (YB1) in the nucleus, which in turn drove the binding of YB1 to its target epidermal growth factor receptor (EGFR) gene promoter to increase its transcription. This in turn increased expression of EGFR and the activation of the downstream MEK/pERK signaling pathway. Our results identify DDX17, stabilized by MTDH, as a powerful oncogene in HCC and suggest that the DDX17/YB1/EGFR axis contributes to tumorigenesis and metastasis of HCC.

18[Formula: see text]-Glycyrrhetinic Acid Inhibits TGF-[Formula: see text]-Induced Epithelial-to-Mesenchymal Transition and Metastasis of Hepatocellular Carcinoma by Targeting STAT3.

18[Formula: see text]-glycyrrhetinic acid (GA) is the active ingredient of the traditional Chinese medicinal herb Glycyrrhizae radix et rhizoma. We previously demonstrated that GA inhibited tumor growth in hepatocellular carcinoma (HCC). However, the effect of GA on transforming growth factor-[Formula: see text] (TGF-[Formula: see text]-induced epithelial-mesenchymal transition (EMT) and metastasis were still unclear. In this study, in vitro transwell assays and immunofluorescence (IF) demonstrated that GA inhibited TGF-[Formula: see text]-induced migration, invasion and EMT of HCC cells. However, it had little effect on the inhibition of proliferation by TGF-[Formula: see text]. Moreover, we confirmed that GA suppressed the metastasis of HCC cells in vivousing an ectopic lung metastasis model. Furthermore, we found that GA inhibited TGF-[Formula: see text]-induced EMT mainly by reducing the phosphorylation of signal transducer and activator of transcription 3 (STAT3), which played an essential role in TGF-[Formula: see text]-induced EMT and cell mobility. Mechanistically, GA inhibited the phosphorylation of STAT3 by increasing the expression of Src homology 2 domain-containing protein tyrosine phosphatases 1 and 2 (SHP1 and SHP2). Therefore, we concluded that GA inhibited TGF-[Formula: see text]-induced EMT and metastasis via the SHP1&SHP2/STAT3/Snail pathway. Our data provide an attractive therapeutic target for future multimodal management of HCC.

Efficacy and safety of tranexamic acid on reducing perioperative blood loss in patients with intertrochanteric fracture / 中国组织工程研究

BACKGROUND: Proximal femoral nail anti-rotation is widely used to treat various intertrochanteric fractures. Although its operation trauma is small, and the blood loss of perioperative period is still large. Tranexamic acid has been gradually used to reduce the bleeding of intertrochanteric fracture. The effectiveness and safety of reducing blood loss during perioperative period were not reported. OBJECTIVE: To explore the safety and efficacy of tranexamic acid on perioperative blood loss in patients with intertrochanteric fracture undergoing proximal femoral nail anti-rotation. METHODS: One hundred and eight patients with intertrochanteric fracture undergoing proximal femoral nail anti-rotation were selected from First Affiliated Hospital, Guangzhou University of Chinese Medicine between January 2015 and January 2017. Among all the subjects, 52 patients who received the operation before January 2016 served as the control group and 56 patients who received the operation after January 2016 were selected as the treatment group. Half an hour before operation, patients in the treatment group received 1 g tranexamic acid dissolved in 250 mL normal saline by intravenous dropping; patients in the control group just received 250 mL normal saline by intravenous dropping. The bleeding volume, blood transfusion volume, hemoglobin, hematocrit, coagulation index, D-dimer levels and complications were compared between the two groups. RESULTS AND CONCLUSION: (1) During perioperative period, actual blood loss, intraoperative blood loss, dominant blood loss, recessive blood loss, volume of drainage, blood transfusion volume and blood transfusion rate were lower in the treatment group than in the control group (P < 0.05). (2) There was no statistically significant difference in the hemoglobin and hematocrit between the two groups before operation (P > 0.05). The hemoglobin and hematocrit of the two groups gradually decreased after the operation, and there was a slight improvement in the fifth day after surgery. At postoperative 2 hours, 1, 3 and 5 days, the hemoglobin and hematocrit of the treatment group were higher than in the control group (P < 0.05). At preoperation and each time point postoperation, prothrombin time, activated partial thromboplastin time, and fibrinogen levels were not statistically significant between the two groups (P > 0.05). Postoperative D-dimer levels in the two groups were significantly higher than preoperation, and there was a return on the fifth day. There was no statistically significant difference between groups at preoperation and each time point of postoperation (P > 0.05). (3) The results suggest that the tranexamic acid can effectively reduce the dominant and recessive blood loss in patients with the intertrochanteric fracture, and it is safe and effective.

Effect of lit-moxa stimulation of Guanyuan (CV 4) acupoint on levels of lactic acid and superoxide dismutase in skeletal muscle of rats.

OBJECTIVE: To observe the effect of lit-moxa stimu- lating acupoint Guanyuan (CV 4) on lactic acid and super-oxide dismutase (SOD) in skeletal muscle after exercise exhaustion. METHODS: Twenty-eight adult male Sprague-Dawley rats were randomly divided into normal control group, exhausted control group, exercise group and moxibustion group using exercise training and mild heating with lit-moxa stick as treatment methods. The exhausted control group, moxibustion group and exercise group received an exhaustive swimming after 20 days of intervention. Swimming exhausted times were recorded. Lactic acid and SOD concentration in soleus muscle were detected and compared between every two groups. RESULTS: The swimming exhausted times of the moxibustion group and the exercise group were significantly increased compare to the exhausted control group (P < 0.05). The lactic acid of the exhausted control group was significantly increased comparing with the normal control group (P < 0.05), and the lactic acid of the moxibustion group and the exercise group were significantly lower than that of the exhausted control group (P < 0.05). The SOD level of the exhausted control group was significantly decreased comparing with the normal control group (P < 0.05), and the SOD level of the moxibustion group and the exercise group were significantly higher than that of the exhausted control group (both, P < 0.05). There was no statistical difference between the moxibustion group and the exercise group. CONCLUSION: With lit moxa stick, heat stimulating acupoint of Guanyuan (CV 4) decreased the levels of lactic acid and SOD in rat's skeletal muscle.

Improved performance of CuInS2 quantum dot-sensitized solar cells based on a multilayered architecture.

This article describes a CuInS2 quantum dot (QD)-sensitized solar cell (QDSSC) with a multilayered architecture and a cascaded energy-gap structure fabricated using a successive ionic-layer adsorption and reaction process. We initially used different metal chalcogenides as interfacial buffer layers to improve unmatched band alignments between the TiO2 and CuInS2 QD sensitizers. In this design, the photovoltaic performance, in terms of the short-circuit current density (JSC), open-circuit voltage (VOC), fill factor (FF), and power conversion efficiency (PCE), was significantly improved. Both JSC and VOC were improved in CuInS2-based QDSSCs in the presence of interfacial buffer layers because of proper band alignment across the heterointerface and the negative band edge movement of TiO2. The PCE of CuInS2-based QDSSCs containing In2Se3 interfacial buffer layers was 1.35%, with JSC=5.83 mA/cm2, VOC=595 mV, and FF=39.0%. We also examined the use of alternative CdS and CdSe hybrid-sensitized layers, which were sequentially deposited onto the In2Se3/CuInS2 configuration for creating favorable cascaded energy-gap structures. Both JSC (11.3 mA cm(-2)) and FF (47.3%) for the CuInS2/CdSe hybrid-sensitized cells were higher than those for CuInS2-based cells (JSC=5.83 mA cm(-2) and FF=39.0%). In addition, the hybrid-sensitized cells had PCEs that were 1.3 times those of cells containing identically pretreated In2Se3 interfacial buffer layers. Additionally, we determined that ZnSe served as a good passivation layer on the surface of CuInS2/CdSe hybrid-sensitized QDs, prevented current leakage from the QDs to electrolytes, and lowered interfacial charge recombination. Under simulated illumination (AM 1.5, 100 mW cm(-2)), multilayered QDSSCs with distinct architectures delivered a maximum external quantum efficiency of 80% at 500 nm and a maximum PCE of 4.55%, approximately 9 times that of QDSSCs fabricated with pristine CuInS2.

B7-H4 expression is elevated in human U251 glioma stem-like cells and is inducible in monocytes cultured with U251 stem-like cell conditioned medium / 癌症

Previous studies indicated that B7-H4, the youngest B7 family, negatively regulates T cell-mediated immunity and is significantly overexpressed in many human tumors. Tumor stem cells are purported to play a role in tumor renewal and resistance to radiation and chemotherapy. However, the link between B7-H4 and tumor stem cells is unclear. In this study, we investigated B7-H4 expression in the medium of human glioma U251 cell cultures. Immunofluorescence results showed that U251 cells cultured in serum-free medium (supplemented with 2% B27, 20 ng/mL epidermal growth factor, 20 ng/mL basic fibroblast growth factor) maintained stem-like cell characteristics, including expression of stem cell marker CD133 and the neural progenitor cell markers nestin and SOX2. In contrast, U251 cells cultured in serum-containing medium highly expressed differentiation marker glial fibrillary acidic protein. Flow cytometry analysis showed serum-free medium-cultured U251 cells expressed higher intracellular B7-H4 than serum-containing medium-cultured U251 cells (24%-35% vs. 8%-11%, P < 0.001). Immunofluorescence in purified monocytes from normal human peripheral blood mononuclear cells revealed moderate expression of B7-H4 after stimulation with conditioned medium from U251 cells cultured in serum-containing medium. Moreover, conditioned medium from U251 stem-like cells had a significant stimulation effect on B7-H4 expression compared with serum-containing conditioned medium (P < 0.01). Negative costimulatory molecule B7-H4 was preferentially expressed in U251 stem-like cells, and conditioned medium from these cells more effectively induced monocytes to express B7-H4 than conditioned medium from U251 cells cultured in the presence of serum. Our results show that U251 stem-like cells may play a more crucial role in tumor immunoloregulation with high expression of B7-H4.

Efficient "green" quantum dot-sensitized solar cells based on Cu2S-CuInS2-ZnSe architecture.

A Cu(2)S-CuInS(2)-ZnSe quantum dot (QD)-sensitized solar cell with cascaded energy gap structures has been fabricated. Under simulated illumination (AM 1.5, 100 mW cm(-2)), the best device is obtained with a Cu(2)S-CuInS(2)-ZnSe QD-sensitized solar cell, yielding a power conversion efficiency of 2.52%.

[Research on the osteogenic ability of 3-Ds interconnected porous titanium].

OBJECTIVE: To evaluate the osteogenic ability of the three-dimensional interconnected porous titanium(TDIPT) coated with bonelike apatite, by the test of the culture of osteoblast in vitro. METHODS: The pure TDIPT was prepared by the high temperature insostatic pressing (HIP) and was divided into two groups. One group of TDIPT was dipped into the 1.5 simulated body fluid (1.5 SBF) and developed the TDIPT coated with bone-like apatite (The test group). Another group was control group (pure TDIPT). The porous titanium of the two groups were all made into standard parts (5 mm x 5 mm x 4 mm) and placed into the 24-hole plates. The osteoblasts were extracted from SD rat. After the primary culture and subculture of the osteoblast in vitro, the osteoblasts were inoculated into the samples in the 24-pole plate and cultured continually. MTT Cell Proliferation Assay was done on the 1st, 3rd, 5th, 7th and 9th day respectively after inoculating. The ALP activity was tested on the 7th, 14th and 21st day, respectively. The collected data were analyzed by use of the student t test. RESULTS: The MTT value and the ALP activity increased with the increasing of the culture time in the two group, but those of the test group was more significant than those of the control group (P < 0.05). Moreover, the osteoblast tachyauxesis and stable adhesion were observed in test group by SEM at the 7th day after culturing. CONCLUSION: The bioactivity of the TDIPT improves significantly after coating with the bone-like apatite onto the surface of the TDIPT.

Research on the osteogenic ability of 3-Ds interconnected porous titanium / 中国骨伤

<p><b>OBJECTIVE</b>To evaluate the osteogenic ability of the three-dimensional interconnected porous titanium(TDIPT) coated with bonelike apatite, by the test of the culture of osteoblast in vitro.</p><p><b>METHODS</b>The pure TDIPT was prepared by the high temperature insostatic pressing (HIP) and was divided into two groups. One group of TDIPT was dipped into the 1.5 simulated body fluid (1.5 SBF) and developed the TDIPT coated with bone-like apatite (The test group). Another group was control group (pure TDIPT). The porous titanium of the two groups were all made into standard parts (5 mm x 5 mm x 4 mm) and placed into the 24-hole plates. The osteoblasts were extracted from SD rat. After the primary culture and subculture of the osteoblast in vitro, the osteoblasts were inoculated into the samples in the 24-pole plate and cultured continually. MTT Cell Proliferation Assay was done on the 1st, 3rd, 5th, 7th and 9th day respectively after inoculating. The ALP activity was tested on the 7th, 14th and 21st day, respectively. The collected data were analyzed by use of the student t test.</p><p><b>RESULTS</b>The MTT value and the ALP activity increased with the increasing of the culture time in the two group, but those of the test group was more significant than those of the control group (P < 0.05). Moreover, the osteoblast tachyauxesis and stable adhesion were observed in test group by SEM at the 7th day after culturing.</p><p><b>CONCLUSION</b>The bioactivity of the TDIPT improves significantly after coating with the bone-like apatite onto the surface of the TDIPT.</p>

Constitution identification and treatment with acupuncture-moxibustion for menopausal women / 中国针灸

According to the theory of constitution and disease prevention of Chinese medicine, kidney deficiency, lack of nourishment of the Thoroughfare Vessel and the Conception Vessel as well as qi sufficiency and blood deficiency are taken as the main features of body constitutions of women during menopausal period. Acupuncture-moxibustion treatment before or in the early stage of menopausal period are discussed initially. Methods of tonifying the kidney and regulate qi and blood are held as the main treating principles. Acupuncture points such as Sanyinjiao (SP 6), Shenshu (BL 23), Guanyuan (CV 4) and Baihui (GV 20) are adopted as the main points. And proper stimulation of needling and moxibustion are applied. Thus, a new way of thinking is provided for disease prevention and health keeping of women during menopausal period in China.

[Effects of three types of veneering porcelain on bending strength of KAVO(TM) Y-TZP/porcelain bilayered structure].

OBJECTIVE: To investigate the effect of three types of veneering porcelain on the bending strength of KAVO Y-TZP/porcelain layered structure. METHODS: KAVO zirconia ceramics were used as the substructure. To form Y-TZP/porcelain bilayered structure, a leucite-based veneering porcelain was fired on the zirconia substructures by slip-casting technique with dentin washbake, and two nano-fluorapatite-based veneering porcelains were fired on the zirconia substructures by either slip-casting or pressed-on technique with or without liner coverage. The bending strength was tested according to ISO 6872 standard, and the veneered surfaces of the fracture samples were analyzed by scanning electron microscopy (SEM). RESULTS: For covering KAVO zirconia core material, the conventional veneering slurry-porcelain combined with liner or wash firing had significant higher bending strength than pressed-on porcelain. SEM showed that the main failure type at the interface was adhesive failure. CONCLUSION: Thin layer sintering using washbake program or liner on KAVO zirconia surface increases the surface wettability, and this procedure may be indispensable when veneering on the surface of dental zirconia.

[Effect of pigmentation on the strength of dental Y-TZP/porcelain bilayered structure].

OBJECTIVE: To investigate the effect of two methods of pigmentation on the flexural strength of dental Y-TZP/porcelain layered structure. METHODS: KaVo zirconia substructures were pigmented by dipping presintered blocks in the coloring solution VITA LL1 and LL5, and colored TZ-3YS zirconia substructures were fabricated by adding pigments before isostatic pressing. The colors No.1 and No.5 were used for the test. The specimens were made in monolithic or bilayered forms, and the flexural strength was tested. XRD and SEM with EDX were used to analyze the characteristics of the surface structure. RESULTS: In KaVo group, no significant differences were found in the flexural strength between white and LL1 and LL5 colored monoclinic materials, nor in bilayered structures. While in TZ-3YS group, significant differences were noted in the flexural strength between color No.5 white and color No.1 monoclinic materials, but not between the latter two subgroups. The flexural strength was significantly lowered by veneering with porcelain in both zirconia groups, and similar findings were observed with the monoclinic materials. Only the tetragonal phase was detected in both of the zirconia groups. CONCLUSION: Pigmentation has no apparent effects on the bonding strength between the veneering porcelain and zirconia. Both coloring methods are appropriate when the concentration of the pigments is under deliberate control.

Effects of three types of veneering porcelain on bending strength of KAVO(TM) Y-TZP/porcelain bilayered structure / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the effect of three types of veneering porcelain on the bending strength of KAVO Y-TZP/porcelain layered structure.</p><p><b>METHODS</b>KAVO zirconia ceramics were used as the substructure. To form Y-TZP/porcelain bilayered structure, a leucite-based veneering porcelain was fired on the zirconia substructures by slip-casting technique with dentin washbake, and two nano-fluorapatite-based veneering porcelains were fired on the zirconia substructures by either slip-casting or pressed-on technique with or without liner coverage. The bending strength was tested according to ISO 6872 standard, and the veneered surfaces of the fracture samples were analyzed by scanning electron microscopy (SEM).</p><p><b>RESULTS</b>For covering KAVO zirconia core material, the conventional veneering slurry-porcelain combined with liner or wash firing had significant higher bending strength than pressed-on porcelain. SEM showed that the main failure type at the interface was adhesive failure.</p><p><b>CONCLUSION</b>Thin layer sintering using washbake program or liner on KAVO zirconia surface increases the surface wettability, and this procedure may be indispensable when veneering on the surface of dental zirconia.</p>

Effect of pigmentation on the strength of dental Y-TZP/porcelain bilayered structure / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the effect of two methods of pigmentation on the flexural strength of dental Y-TZP/porcelain layered structure.</p><p><b>METHODS</b>KaVo zirconia substructures were pigmented by dipping presintered blocks in the coloring solution VITA LL1 and LL5, and colored TZ-3YS zirconia substructures were fabricated by adding pigments before isostatic pressing. The colors No.1 and No.5 were used for the test. The specimens were made in monolithic or bilayered forms, and the flexural strength was tested. XRD and SEM with EDX were used to analyze the characteristics of the surface structure.</p><p><b>RESULTS</b>In KaVo group, no significant differences were found in the flexural strength between white and LL1 and LL5 colored monoclinic materials, nor in bilayered structures. While in TZ-3YS group, significant differences were noted in the flexural strength between color No.5 white and color No.1 monoclinic materials, but not between the latter two subgroups. The flexural strength was significantly lowered by veneering with porcelain in both zirconia groups, and similar findings were observed with the monoclinic materials. Only the tetragonal phase was detected in both of the zirconia groups.</p><p><b>CONCLUSION</b>Pigmentation has no apparent effects on the bonding strength between the veneering porcelain and zirconia. Both coloring methods are appropriate when the concentration of the pigments is under deliberate control.</p>

[Structure and properties of colored dental tetragonal zirconia stabilized by yttrium ceramics].

OBJECTIVE: To investigate the structure, mechanical and low temperature aging properties of colored dental zirconia ceramics. METHODS: 5 graded colored dental zirconia ceramics were made by adding colorants and their combinations into a 3Y-TZP (tetragonal zirconia stabilized by 3mol% yttrium) powder, the green body were compacted at 200 MPa, pre-sinter at 1,050 degrees C and maintained for 2 h, then densely sintered at 1,500 degrees C for 2 h. Specimens were cut from each of the 5 graded colored blocks. Physical, mechanical properties as well as chemical stability were tested, microstructure were observed, crystalline phase were identified by X-ray diffraction (XRD), aging properties were assessed by measurement of the relative content of monoclinic phase and bending strength testing. RESULTS: The overall density of colored zirconia ceramics was over 99.7%, linear shrinkage was about 20%, while thermal expansion coefficient was about 11 x 10(-6) x degrees C(-1), the crystalline phase was tetragonal, bending strength was over 900 MPa which was slightly lowered than that of the uncolored zirconia, fracture toughness was slightly higher. Good chemical stability in acetic acid was observed. After aging treatment, tetragonal-to-monoclinic phase transformation was detected up to 40%, while bending strength was not significantly degraded. CONCLUSION: The results showed that colored 3Y-TZP ceramics presented good mechanical properties even after aging treatments, and was suitable for dental clinical use.

Structure and properties of colored dental tetragonal zirconia stabilized by yttrium ceramics / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the structure, mechanical and low temperature aging properties of colored dental zirconia ceramics.</p><p><b>METHODS</b>5 graded colored dental zirconia ceramics were made by adding colorants and their combinations into a 3Y-TZP (tetragonal zirconia stabilized by 3mol% yttrium) powder, the green body were compacted at 200 MPa, pre-sinter at 1,050 degrees C and maintained for 2 h, then densely sintered at 1,500 degrees C for 2 h. Specimens were cut from each of the 5 graded colored blocks. Physical, mechanical properties as well as chemical stability were tested, microstructure were observed, crystalline phase were identified by X-ray diffraction (XRD), aging properties were assessed by measurement of the relative content of monoclinic phase and bending strength testing.</p><p><b>RESULTS</b>The overall density of colored zirconia ceramics was over 99.7%, linear shrinkage was about 20%, while thermal expansion coefficient was about 11 x 10(-6) x degrees C(-1), the crystalline phase was tetragonal, bending strength was over 900 MPa which was slightly lowered than that of the uncolored zirconia, fracture toughness was slightly higher. Good chemical stability in acetic acid was observed. After aging treatment, tetragonal-to-monoclinic phase transformation was detected up to 40%, while bending strength was not significantly degraded.</p><p><b>CONCLUSION</b>The results showed that colored 3Y-TZP ceramics presented good mechanical properties even after aging treatments, and was suitable for dental clinical use.</p>

[Preparation and chromaticity properties of colored dental 3Y-TZP ceramics].

OBJECTIVE: To obtain and investigate the chromaticity properties of colored dental 3Y-TZP ceramics with different colorant combinations. METHODS: Colorant combinations were mixed with TZ-3Y-S powder, then the mixtures were compacted at 200 MPa using cold isostatic pressure, densely sintered at 1500 degrees C for 2 h forming 5 graded colored dental zirconia ceramics. Specimen were sectioned into 10 mm x 10 mm x 0.5 mm and 10 mm x l0 mmx 1 mm slices from the sintered blocks. Color measurement was performed under black background using spectrophotometer. The chromaticity properties were compared with that of the VITA In-Ceram YZ shade guide. RESULTS: Five colored dental zirconia ceramics were obtained. The lightness decreased gradually, and the chroma value increased gradually. The color differences of the two thickness specimens were little. The parameters of the color space were L*: 67.76-77.78; a*: -2.19-3.80; b*: 12.13-25.01, which was similar with that of the VITA In-Ceram YZ shade guide, while the lowest value of lightness was relatively higher than that of the VITA In-Ceram YZ shade guide. CONCLUSION: Colored 3Y-TZP dental ceramics are suitable for clinical use. There is a need to develop more darkness shaded zirconia dental ceramics.

[In vitro evaluation of low-temperature aging effects of Y2O3 stabilized tetragonal zirconia polycrystals dental ceramics].

OBJECTIVE: To investigate the influence of in vitro low-temperature degradation (LTD) treatment on the structural stability of 5 kinds of Y2O3 stabilized tetragonal zirconia polycrystals (Y-TZP) dental ceramics. METHODS: TZ-3YS powder was compacted at 200 MPa using cold isostatic pressure and pre-sintered at 1050 degrees C for 2 h forming presintered blocks. Specimens were sectioned into 15 mm x 15 mm x 1.5 mm slices from blocks of TZ-3YS, Vita In-Ceram YZ, Ivoclar, Cercon Smart, and Kavo Y-TZP presintered blocks, 18 slices for each brand, and then densely sintered. Specimens were divided into 6 groups and subjected to an accelerated aging test carried out in an autoclave in steam at 134 degrees C, 0.2 MPa, for 0, 1, 2, 3, 4, and 5 h. X-ray diffraction (XRD) was used to identify crystal phases and relative content of monoclinic phase was calculated. Specimens for three-point bending test were fabricated using TZ-3YS ceramics according to the ISO 6872 standard and bending strength was tested before and after aging. The polished and aging specimens of TZ-3YS and Cercon Smart zirconia ceramics were observed by atomic force microscopy (AFM) to evaluate surface microstructure. RESULTS: Tetragonal-to-monoclinic phase transformation was detected for specimens of TZ-3YS, Vita In-Ceram YZ, Ivoclar, and Kavo zirconia ceramics except for Cercon Smart ceramics after aging, and the relative content of monoclinic phase was increasing with the prolonged aging time. TZ-3YS was the most affected material, Kavo took the second, and Vita and Ivoclar were similar. Aging had no significant negative effects on flexural strength of TZ-3YS with average bending strength being over 1100 MPa. The nucleation and growth of monoclinic phase were detected by AFM in surface of Cercon Smart zirconia in which monoclinic phase was not detected by XRD. CONCLUSIONS: The results suggest that LTD of dental Y-TZP is time dependent, but the aging test does not reduce the flexural strength of TZ-3YS. The long-term clinical serviceability of dental Y-TZP needs further observation.

In vitro evaluation of low-temperature aging effects of Y2O3 stabilized tetragonal zirconia polycrystals dental ceramics / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To investigate the influence of in vitro low-temperature degradation (LTD) treatment on the structural stability of 5 kinds of Y2O3 stabilized tetragonal zirconia polycrystals (Y-TZP) dental ceramics.</p><p><b>METHODS</b>TZ-3YS powder was compacted at 200 MPa using cold isostatic pressure and pre-sintered at 1050 degrees C for 2 h forming presintered blocks. Specimens were sectioned into 15 mm x 15 mm x 1.5 mm slices from blocks of TZ-3YS, Vita In-Ceram YZ, Ivoclar, Cercon Smart, and Kavo Y-TZP presintered blocks, 18 slices for each brand, and then densely sintered. Specimens were divided into 6 groups and subjected to an accelerated aging test carried out in an autoclave in steam at 134 degrees C, 0.2 MPa, for 0, 1, 2, 3, 4, and 5 h. X-ray diffraction (XRD) was used to identify crystal phases and relative content of monoclinic phase was calculated. Specimens for three-point bending test were fabricated using TZ-3YS ceramics according to the ISO 6872 standard and bending strength was tested before and after aging. The polished and aging specimens of TZ-3YS and Cercon Smart zirconia ceramics were observed by atomic force microscopy (AFM) to evaluate surface microstructure.</p><p><b>RESULTS</b>Tetragonal-to-monoclinic phase transformation was detected for specimens of TZ-3YS, Vita In-Ceram YZ, Ivoclar, and Kavo zirconia ceramics except for Cercon Smart ceramics after aging, and the relative content of monoclinic phase was increasing with the prolonged aging time. TZ-3YS was the most affected material, Kavo took the second, and Vita and Ivoclar were similar. Aging had no significant negative effects on flexural strength of TZ-3YS with average bending strength being over 1100 MPa. The nucleation and growth of monoclinic phase were detected by AFM in surface of Cercon Smart zirconia in which monoclinic phase was not detected by XRD.</p><p><b>CONCLUSIONS</b>The results suggest that LTD of dental Y-TZP is time dependent, but the aging test does not reduce the flexural strength of TZ-3YS. The long-term clinical serviceability of dental Y-TZP needs further observation.</p>

Preparation and chromaticity properties of colored dental 3Y-TZP ceramics / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To obtain and investigate the chromaticity properties of colored dental 3Y-TZP ceramics with different colorant combinations.</p><p><b>METHODS</b>Colorant combinations were mixed with TZ-3Y-S powder, then the mixtures were compacted at 200 MPa using cold isostatic pressure, densely sintered at 1500 degrees C for 2 h forming 5 graded colored dental zirconia ceramics. Specimen were sectioned into 10 mm x 10 mm x 0.5 mm and 10 mm x l0 mmx 1 mm slices from the sintered blocks. Color measurement was performed under black background using spectrophotometer. The chromaticity properties were compared with that of the VITA In-Ceram YZ shade guide.</p><p><b>RESULTS</b>Five colored dental zirconia ceramics were obtained. The lightness decreased gradually, and the chroma value increased gradually. The color differences of the two thickness specimens were little. The parameters of the color space were L*: 67.76-77.78; a*: -2.19-3.80; b*: 12.13-25.01, which was similar with that of the VITA In-Ceram YZ shade guide, while the lowest value of lightness was relatively higher than that of the VITA In-Ceram YZ shade guide.</p><p><b>CONCLUSION</b>Colored 3Y-TZP dental ceramics are suitable for clinical use. There is a need to develop more darkness shaded zirconia dental ceramics.</p>