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OBJECTIVES@#This study aimed to evaluate the color stability of tetracycline teeth restored with ceramic veneers of different thicknesses combined with different resin cement systems after aging.@*METHODS@#Twenty patients with tetracycline teeth, including two maxillary central incisors, were selected clinically. The patients were randomly divided into four groups and restored with 0.5 and 0.75 mm ceramic veneers by using a veneer adhesive system, either with light-cured or dual-cured reaction. The color difference (ΔE) values after cementation and 1, 6, 12, and 24 months of use were obtained by quantification of L*, a*, and b* values with a colorimeter. The results were analyzed statistically with two-way ANOVA and Student's @*RESULTS@#The ΔE values of ceramic veneers detected after aging were less than 2.25. The 0.5 mm groups exhibited greater color change than the 0.75 mm-thick veneers (@*CONCLUSIONS@#Resin cements and veneer thickness influence the color of ceramic veneers after aging. Cementation of veneers with either dual- or light-cured resin cements does not affect the long-term color stability of tetracycline teeth differently.
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Humans , Ceramics , Color , Dental Porcelain , Dental Veneers , Materials Testing , Resin Cements , TetracyclinesABSTRACT
Aim To observe whether matrix metallo-proteinase-14 ( MMP-14) and tissue matrix metallopro-teinase inhibitor-4 ( TIMP-4) were involved in the car-diac-protection of mitochondrial aldehyde dehydrogen-ase 2 ( ALDH2) against high glucose induced rat pri-mary cardiomyocyte injury. Methods Rat primary cardiomyocytes were cultured. The cardiomyocyte via-bility was detected by MTT assay at different concentra-tion of glucose at different time point. After established high glucose-induced cardiomyocytes injury model, cardiomyocytes were randomly divided into 4 groups:normal control group ( NG, glucose at 5.5 mmol· L-1) , NG + Alda-1 group ( Alda-1 at 20 μmol·L-1) , high glucose group ( HG, glucose at 30 mmol·L-1) and HG+Alda-1 group. The cell viability at 48 h and oxidative stress level were detected by MTT and DHE staining methods. The protein expressions of ALDH2, MMP-14 and TIMP-4 were determined by Western blot. Results The cardiomyocytes injury model was established according to the cell activity result. Com-pared with NG group, the cell viability, the protein ex-pressions of ALDH2, MMP-14, the ratio of MMP-14/TIMP-4 were decreased, TIMP-4 protein expression and the level of oxidative stress were increased in HG group. Compared with HG group, in HG + Alda-1 group, the cell viability, the protein expressions of AL-DH2, MMP-14, the ratio of MMP-14/TIMP-4 were in-creased, the levels of oxidative stress and TIMP-4 pro-tein expression were decreased. Conclusion Activa-tion of mitochondrial ALDH2 may relieve high glucose induced cardiomyocytes injury. The protective effect was likely related to the inhibition of oxidative damage, down-regulation of MMP-14 and up-regulation of TIMP-4 proteins.
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<p><b>OBJECTIVE</b>To investigate the effect of dexmedetomidine postconditioning in alleviating myocardial ischemia-reperfusion (IR) injury and inflammation in diabetic mellitus rats.</p><p><b>METHODS</b>Thirty normal male Sprauge Dawley (SD) rats were randomly allocated into 3 groups (n=10), namely the sham-operated group, IR group, and dexmedetomidine postconditioning (DP) group. Similarly, another thirty diabetic SD rats were also randomly allocated into diabetic sham (DM-S) group, diabetic IR (DM-IR) group and diabetic dexmedetomidine postconditioning (DM-DP) group. The mean arterial pressure (MAP), heart rate (HR) and the rate pressure product (RPP) were recorded at baseline, after 30 min of ischemia, and at 30 and 120 min during reperfusion. Myocardial infarct size was analyzed by TTC double staining method, and plasma levels of CTnI, TNF-a, IL-6, IL-10 and IL-1β were measured at 120 min of reperfusion.</p><p><b>RESULTS</b>Compared with those in the sham-operated group, normal and diabetic rats in IR and DP groups showed significantly lowered MAP, HR, and RPP and increased levels of plasma CTnI, TNF-a, IL-6, IL-10 and IL-1β levels after 30 min of ischemia and at 30 min and 120 min of reperfusion (P<0.05). Compared with those in the IR group, the normal rats in DP group showed decreased MAP, HR, and RPP at 30 min of ischemia and at 30 min of reperfusion, which increased at 120 min of reperfusion (P<0.05); the infarct size and plasma CTnI, TNF-a, IL-6 and IL-1β levels were decreased while IL-10 was increased in DP group (P<0.05). Compared with those in DP group, the rats in DM-DP group showed similar MAP, HR and RPP (P>0.05) but significantly increased infarct size and plasma CTnI, TNF-a, IL-6 and IL-1β levels (P<0.05).</p><p><b>CONCLUSION</b>Dexmedetomidine postconditioning may produce a cardioprotective effect against myocardial IR injury in normal rats by alleviating inflammation, but can not reduce the release of inflammatory mediators in diabetic rats to improve myocardial infarction.</p>
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<p><b>OBJECTIVE</b>To investigate the changes of autophagy in ischemic myocardium of rats treated with fasudil for inhibiting Rho kinase.</p><p><b>METHODS</b>The hearts isolated from male Sprague-Dawley rats were subjected to 30 min of occlusion of the left anterior descending artery followed by 120 min of reperfusion with or without treatment with fasudil or fasudil+Wort. The left ventricular hemodynamics were continuously recorded, and the coronary effluent was collected during the reperfusion to determine lactate dehydrogenase (LDH) levels. The mRNA expressions of autophagy-related genes Atg5 and Beclin1 and apoptosis-related genes bax and bcl-2 were detected by RT-PCR, and the protein expression of caspase-3 was detected by Western blotting.</p><p><b>RESULTS</b>Compared with I/R group, fasudil significantly improved the left ventricular developed pressure, maximal rise/fall rate of left ventricular pressure and rate pressure product, reduced LDH release during reperfusion, increased Atg5 and Beclin1 mRNA expression and the ratio of Bcl-2/Bax, and lowered caspase 3 protein expression. The autophagy inhibitor Wort significantly attenuated the effect of fasudil in the rat hearts.</p><p><b>CONCLUSION</b>Fasudil treatment for inhibiting Rho kinase promoted autophagy in ex vivo rat heart to protect against myocardial ischima-reperfusion injury possibly by reducing apoptosis of the cardiac myocytes.</p>
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<p><b>OBJECTIVE</b>To develop a method of three-dimensional computer aided design (CAD) of post-and-core restoration.</p><p><b>METHODS</b>Two plaster casts with extracted natural teeth were used in this study. The extracted teeth were prepared and scanned using tomography method to obtain three-dimensional digitalized models. According to the basic rules of post-and-core design, posts, cores and cavity surfaces of the teeth were designed using the tools for processing point clouds, curves and surfaces on the forward engineering software of Tanglong prosthodontic system. Then three-dimensional figures of the final restorations were corrected according to the configurations of anterior teeth, premolars and molars respectively.</p><p><b>RESULTS</b>Computer aided design of 14 post-and-core restorations were finished, and good fitness between the restoration and the three-dimensional digital models were obtained. Appropriate retention forms and enough spaces for the full crown restorations can be obtained through this method.</p><p><b>CONCLUSIONS</b>The CAD of three-dimensional figures of the post-and-core restorations can fulfill clinical requirements. Therefore they can be used in computer-aided manufacture (CAM) of post-and-core restorations.</p>
Subject(s)
Humans , Computer-Aided Design , Dental Prosthesis Design , Methods , Post and Core TechniqueABSTRACT
<p><b>OBJECTIVE</b>As a new kind of reinforcing filler, ultrafine diamond (UFD) is added into photocurable composite core materials. The properties of the materials are then measured to see if there is any improvement.</p><p><b>METHODS</b>Different content of barium glass and UFD were added into resin matrix to fabricate six groups of photocurable composite core materials. For each group of the materials, the flexural strength, Vicker's micro-hardness and depth of cure were measured. Data of the flexural strength and Vicker's micro-hardness was then collected and analyzed by One-Way ANOVA.</p><p><b>RESULTS</b>For the two kinds of composites with barium glass of 60% and 70%, only a small quantity of modified UFD with 0.2% weight percentage could improve the flexural strength of the composites by 34% and 21% respectively, the microhardness was improved by 23% and 30% respectively. The depth of cure of the composite core materials were more than 2 mm, which had reached the demand of the corresponding ISO criteria. The addition of UFD could make the composite core materials darker and grayer.</p><p><b>CONCLUSION</b>Micro-quantity of UFD can improve the mechanical properties of composite resins notably, and it will not affect the curability of the materials, but the defect in the color need to be reformed.</p>