IPS e.max Press铸瓷与合金嵌体治疗后牙牙体缺损效果对比研究

目的探讨IPS e.max Press铸瓷与合金嵌体治疗后牙牙体缺损的效果。方法前瞻性纳入2020-05—2022-05三门峡市中心医院口腔科收治的后牙牙体缺损患者,根据修复材料分为IPS e.max Press铸瓷嵌体组(铸瓷组)和合金嵌体组(合金组)。比较2组患者的基线资料。治疗前后检测患者的龈沟液中炎性因子、评价牙周健康情况。治疗3个月后评价牙体缺损边缘密合度和美牙效果。结果共纳入86例(132颗牙)患者,每组43例(66颗牙)。2组患者的基线资料差异无统计学意义(P>0.05)。治疗后铸瓷组患者的IL-6、IL-8、CXCL16水平和GI、SBI及PLI评分均低于合金组;牙体缺损边缘密合度优于合金组,美牙效果满意率高于合金组。差异均有统计学意义(P<0.05)。结论与合金嵌体比较,采用IPS e.max Press铸瓷嵌体治疗后牙牙体缺损有利于降低龈沟液中炎性因子水平,改善牙周健康状况和牙体缺损边缘密合度,并可提高患者对美牙效果的满意度。但仍需进行更大样本量的前瞻性随机对照研究予以证实。

IPS e.max press热压铸造陶瓷全冠及二氧化锆全瓷冠对前牙修复患者牙龈健康美观度的影响

目的:比较IPS e.max press热压铸造陶瓷全冠及二氧化锆全瓷冠对前牙修复患者牙龈健康、美观度的影响,为前牙美学修复的材料选择提供临床参考。方法:以2021年5月至2022年5月于我院接受前牙修复的104例患者为研究对象,以随机数字表法分为两组,分别52例。观察组、对照组分别以IPS e.max press铸瓷全冠、二氧化锆全瓷冠修复,比较两组患者的临床修复效果及修复后的牙龈指数、菌斑指数、龈沟出血指数、龈沟液炎性因子水平。结果:观察组边缘密合度、继发龋情况均优于对照组(P<0.05);修复后,观察组牙龈指数、菌斑指数等显著小于对照组,龈沟液IL-6、IL-8及TNF-α水平显著低于对照组(P<0.05);修复12个月后,观察组PES评分高于对照组(P<0.05)。结论:相比于二氧化锆全瓷冠,IPS e.max press铸瓷全冠具有良好的前牙美学修复效果,可降低龈沟液炎性因子水平,改善牙龈健康,并能提高前牙美观度。

Effect of hot isostatic pressure on the microstructure and tensile properties of γ'-strengthened superalloy fabricated through induction-assisted directed energy deposition

The microstructure characteristics and strengthening mechanism of Inconel738LC(IN-738LC) alloy prepared by using induction-assisted directed energy deposition(IDED) were elucidated through the investigation of samples subjected to IDED under 1050℃ preheating with and without hot isostatic pressing(HIP,1190℃,105 MPa,and 3 h).Results show that the as-deposited sample mainly consisted of epitaxial columnar crystals and inhomogeneously distributed γ’ phases in interdendritic and dendritic core regions.After HIP,grain morphology changed negligibly,whereas the size of the γ’ phase became increasingly even.After further heat treatment(HT,1070℃,2 h + 845℃,24 h),the γ’ phase in the as-deposited and HIPed samples presented a bimodal size distribution,whereas that in the as-deposited sample showed a size that remained uneven.The comparison of tensile properties revealed that the tensile strength and uniform elongation of the HIP + HTed sample increased by 5% and 46%,respectively,due to the synergistic deformation of bimodal γ’phases,especially large cubic γ’ phases.Finally,the relationship between phase transformations and plastic deformations in the IDEDed sample was discussed on the basis of generalized stability theory in terms of the trade-off between thermodynamics and kinetics.

Improving mechanical properties and high-temperature oxidation of press hardened steel by adding Cr and Si

This work investigated the effect of Cr and Si on the mechanical properties and oxidation resistance of press hardened steel.Results indicated that the microstructure of the Cr-Si micro-alloyed press hardened steel consisted of lath martensite,M_(23)C_(6)carbides,and retained austenite.The retained austenite and carbides are responsible for the increase in elongation of the micro-alloyed steel.In addition,after oxidation at 930℃for 5 min,the thickness of the oxide scales on the Cr-Si micro-alloyed press hardened steel is less than 5μm,much thinner than 45.50μm-thick oxide scales on 22MnB5.The oxide scales of the Cr-Si micro-alloyed steel are composed of Fe_(2)O_(3),Fe_(3)O_(4),mixed spinel oxide(FeCr_(2)O_(4)and Fe_(2)SiO_(4)),and amorphous SiO_(2).Adding Cr and Si significantly reduces the thickness of the oxide scales and prevents the generation of the FeO phase.Due to the increase of spinel FeCr_(2)O_(4)and Fe_(2)SiO_(4)phase in the inner oxide scale and the amorphous SiO_(2)close to the substrate,the oxidation resistance of the Cr-Si micro-alloyed press hardened steel is improved.

Tension-Compression Asymmetry in Ultrafine-grained Commercially Pure Ti Processed by ECAP

A homogenous microstructure of ultrafine-grained (UFG) commercially pure (CP) Ti characterized by equiaxed grains/subgrains with an average grain size of about 150 nm and strong prismatic fiber texture were obtained after 4 passes of equal channel angular pressing (ECAP).Tension–compression asymmetry in yield and work hardening behavior of UFG CP Ti were investigated by uniaxial tension and compression tests.The experimental results reveal that UFG CP Ti exhibits a relatively obvious tensioncompression asymmetry in yielding and work hardening behavior.The basal and prismaticslip are suppressed either for tension or compression,which is the easiest to activate.The tension twin system{1012}<1011> easily activated in compression deformation due to the prismatic fiber texture based on the Schmidt factor,consequently resulting in a lower yield strength under compression than tension.ECAP can improve the tension-compression asymmetry of CP Ti due to grain refinement.The interaction among the dislocations,grain boundaries and deformation twins are the main work hardening mechanisms for compression deformation,while the interaction between the dislocations and grain boundaries for tension deformation.Deformation twins lead to the higher work hardening under compression than tension.

Effect of the capsule on deformation and densification behavior of nickel-based superalloy compact during hot isostatic pressing

The Shima yield criterion used in finite element analysis for nickel-based superalloy powder compact during hot isostatic pressing(HIP) was modified through uniaxial compression experiments. The influence of cylindrical capsule characteristics on FGH4096M superalloy powder compact deformation and densification behavior during HIP was investigated through simulations and experiments. Results revealed the simulation shrinkage prediction fitted well with the experimental shrinkage including a maximum shrinkage error of 1.5%. It was shown that the axial shrinkage was 1.7% higher than radial shrinkage for a cylindrical capsule with the size of ∮50 mm × 100 mm due to the force arm difference along the axial and radial direction of the capsule. The stress deviated from the isostatic state in the capsule led to the uneven shrinkage and non-uniform densification of the powder compact. The ratio of the maximum radial displacement to axial displacement increased from0.47 to 0.75 with the capsule thickness increasing from 2 to 4 mm. The pressure transmission is related to the capsule thickness, the capsule material performance, and physical parameters in the HIP process.

Effects of microstructure characteristics on the tensile properties and fracture toughness of TA15 alloy fabricated by hot isostatic pressing

Powder hot isostatic pressing(HIP) is an effective method to achieve near-net-shape manufacturing of high-quality complex thinwalled titanium alloy parts, and it has received extensive attention in recent years. However, there are few reports about the microstructure characteristics on the strengthening and toughening mechanisms of powder hot isostatic pressed(HIPed) titanium alloys. Therefore, TA15powder was prepared into alloy by HIP approach, which was used to explore the microstructure characteristics at different HIP temperatures and the corresponding tensile properties and fracture toughness. Results show that the fabricated alloy has a “basket-like structure” when the HIP temperature is below 950℃, consisting of lath clusters and surrounding small equiaxed grains belts. When the HIP temperature is higher than 950℃, the microstructure gradually transforms into the Widmanstatten structure, accompanied by a significant increase in grain size. The tensile strength and elongation are reduced from 948 MPa and 17.3% for the 910℃ specimen to 861 MPa and 10% for the 970℃ specimen.The corresponding tensile fracture mode changes from transcrystalline plastic fracture to mixed fracture including intercrystalline cleavage.The fracture toughness of the specimens increases from 82.64 MPa·m^(1/2)for the 910℃ specimen to 140.18 MPa·m^(1/2)for the 970℃ specimen.Specimens below 950℃ tend to form holes due to the prior particle boundaries(PPBs), which is not conducive to toughening. Specimens above 950℃ have high fracture toughness due to the crack deflection, crack branching, and shear plastic deformation of the Widmanstatten structure. This study provides a valid reference for the development of powder HIPed titanium alloy.

腔内注射雷珠单抗联合Ex-press引流植入术治疗新生血管性青光眼的疗效

目的探讨腔内注射雷珠单抗联合Ex-press引流植入术治疗新生血管性青光眼(NVG)的疗效。方法选取2019年7月至2020年7月我院眼科收治的NVG患者100例(100眼)作为研究对象,按照随机数字表法将其分为对照组和观察组,每组50例(50眼)。对照组给予单纯Ex-press引流植入术,观察组给予腔内注射雷珠单抗联合Ex-press引流植入术。比较2组患者治疗前后眼压、视力水平及治疗有效率。采用ELISA法测定并比较2组患者血浆及房水中转化生长因子β1(TGF-β1)和血清及房水中血管内皮生长因子(VEGF)、白介素-6(IL-6)及促红细胞生成素(EPO)水平。记录2组患者不良反应的发生情况。结果2组患者治疗后4周、3个月的眼压均较治疗前降低(P<0.05),且观察组眼压明显低于对照组(P<0.05);观察组患者治疗后4周、3个月的视力改善优于对照组(P<0.05)。观察组的治疗有效率明显高于对照组(P<0.05)。2组患者治疗后4周血浆中TGF-β1水平,血清中VEGF、IL-6水平和房水中VEGF、IL-6、TGF-β1、EPO水平均明显降低(P<0.05),且观察组降低更明显(P<0.05)。2组患者不良反应发生率比较差异无统计学意义(P>0.05)。结论腔内注射雷珠单抗联合Ex-press引流植入术治疗NVG可有效降低眼内压,改善患者视力,下调TGF-β1、EPO水平,进而提高患者治疗有效率。

Simple shear extrusion versus equal channel angular pressing:A comparative study on the microstructure and mechanical properties of an Mg alloy

Two severe plastic deformation(SPD)techniques of simple shear extrusion(SSE)and equal channel angular pressing(ECAP)were employed to process an extruded Mg-6Gd-3Y-1.5Ag(wt%)alloy at 553 K for 1,2,4 and 6 passes.The microstructural evolutions were studied by electron back scattered diffraction(EBSD)analysis and transmission electron microscopy(TEM).The initial grain size of 7.5μm in the extruded alloy was reduced to about 1.3μm after 6 SPD passes.Discontinuous dynamic recrystallization was suggested to be operative in both SSE and ECAP,with also a potential contribution of continuous dynamic recrystallization at the early stages of deformation.The difference in the shear strain paths of the two SPD techniques caused different progression rate of dynamic recrystallization(DRX),so that the alloys processed by ECAP exhibited higher fractions of recrystallization and high angle grain boundaries(HAGBs).It was revealed that crystallographic texture was also significantly influenced by the difference in the strain paths of the two SPD methods,where dissimilar basal plane texture components were obtained.The compression tests,performed along extrusion direction(ED),indicated that the compressive yield stress(CYS)and ultimate compressive strength(UCS)of the alloys after both SEE and ECAP augmented continuously by increasing the number of passes.ECAP-processed alloys had lower values of CYS and UCS compared to their counterparts processed by SSE.This difference in the mechanical responses was attributed to the different configurations of basal planes with respect to the loading direction(ED)of each SPD technique.

Effect of hot isostatic pressing processing parameters on microstructure and properties of Ti60 high temperature titanium alloy

Hot isostatic pressing parameters are critical to Ti60 high temperature titanium alloy castings which have wide application perspective in aerospace.In order to obtain optimal processing parameters,the effects of hot isostatic pressing parameters on defects,composition uniformity,microstructure and mechanical properties of Ti60 cast high temperature titanium alloy were investigated in detail.Results show that increasing temperature and pressure of hot isostatic pressing can reduce defects,especially,the internal defects are substantially eliminated when the temperature exceeds 920℃or the pressure exceeds 125 MPa.The higher temperature and pressure can improve the microstructure uniformity.Besides,the higher pressure can promote the composition uniformity.With the temperature increases from 880℃to 960℃,α-laths are coarsened.But with increasing pressure,the grain size of prior-βphase,the widths ofα-laths andα-colony are reduced.The tensile strength of Ti60 alloy is 949 MPa,yield strength is 827 MPa,and the elongation is 11%when the hot isostatic pressing parameters are 960℃/125 MPa/2 h,which exhibits the best match between the strength and plasticity.

Superplastic behavior of a fine-grained Mg-Gd-Y-Ag alloy processed by equal channel angular pressing

An extruded Mg-6Gd-3Y-1.5Ag(wt%) alloy was processed by 6 passes of equal channel angular pressing(ECAP) at 553 K using route Bc to refine the microstructure. Electron back-scattered diffraction(EBSD) analysis showed a fully recrystallized microstructure for the extruded alloy with a mean grain size of 8.6 μm. The microstructure of the ECAP-processed alloy was uniformly refined through dynamic recrystallization(DRX). This microstructure contained fine grains with an average size of 1.3 μm, a high fraction of high angle grain boundaries(HAGBs), and nano-sized Mg_(5)Gd-type particles at the boundaries of the DRXed grains, detected by transmission electron microscopy(TEM). High-temperature shear punch testing(SPT) was used to evaluate the superplastic behavior of both the extruded and ECAP-processed alloys by measuring the strain rate sensitivity(SRS) index(m-value). While the highest m-value for the extruded alloy was measured to be 0.24 at 673 K, the ECAP-processed alloy exhibited much higher m-values of 0.41 and 0.52 at 598 and 623 K, respectively,delineating the occurrence of superplastic flow. Based on the calculated average activation energy of 118 kJ mol^(-1) and m-values close to 0.5, the deformation mechanism for superplastic flow at the temperatures of 598 and 623 K for the ECAP-processed alloys was recognized to be grain boundary sliding(GBS) assisted by grain boundary diffusion.

The Press of the State of Mato Grosso and the Civil-Military Coup of 1964

In the last few years,the media has been taken as a source and object of study in the area of history.Researchers have already demonstrated that Folha de S.Paulo,O Estado de S.Paulo,Diário de S.Paulo,O Globo,Jornal do Brasil,Tribuna da Imprensa,and Correio da Manhãcontributed to the civil-military coup of 1964.In addition to them,periodicals produced in the State of Mato Grosso also played an important role in the process that culminated in the overthrow of President João Goulart.O Progresso,O Mato-grossense,O Correio do Estado,and O Estado de Mato Grosso are a few examples.In this article,the aim is to demonstrate the role of the written press in the State of Mato Grosso in the civil-military coup of 1964.Therefore,it is understood that newspapers play a role in the political game and in the construction of the historical event itself.

IPS e.max Press全瓷贴面在前牙修复中的应用

目的评价IPS e.max Press全瓷贴面在前牙美容修复应用中的临床疗效。方法对52例患者的103颗前牙进行IPS e.max Press全瓷贴面修复,于修复体粘接后每半年进行复查评价其临床效果。结果经过2年的复查,有1个瓷贴面发生折裂,2个出现裂纹,2颗贴面修复的基牙有轻度的牙龈炎症,无瓷贴面脱落。结论 IPS e.max Press全瓷贴面修复能有效保存牙体组织,获得满意的美学修复效果,在前牙美容修复中具有良好的应用前景。

氢氟酸和偶联剂的应用对e.max~ Press铸瓷与树脂水门汀黏结强度的影响

目的:观察酸蚀和偶联剂处理IPS e.max Press铸瓷对瓷与树脂水门汀黏结强度的影响。方法:将126个试件分为7组,分别以50g/L氢氟酸酸蚀0、10、20、30、60、120、180s后一半使用偶联剂,一半不使用偶联剂,与树脂水门汀黏结后测定剪切黏结强度,每组取2个试件进行扫描电镜观察。结果:仅酸蚀组的黏结强度最高可达33.98MPa(60s),对照组6.76MPa;单纯使用偶联剂可达22.23MPa,结合酸蚀最高可达35.16MPa(30s);扫描电镜可见酸蚀时间不同及是否使用偶联剂与瓷表面微观形貌有直接关系。结论:瓷酸蚀后配以偶联剂的使用可提高黏结强度,并可在较短时间就获得理想的黏结强度。

In-situ ultrasonic calibrations of pressure and temperature in a hinge-type double-stage cubic large volume press

Here,simultaneous in-situ calibration of pressures and temperatures was performed in a hinge-type second-stage cubic large volume press(LVP)up to 15 GPa and 1400 K by an acoustic travel-time approach.Based on the recently reported P-tSand P-T-tP-tSequations for Al2O3buffer rod,the cell pressures and temperatures in the chamber of LVP were insitu determined,in comparison with those by conventional off-line(or fixed-points)pressure calibration method and direct thermocouple measurement,respectively.It is found that the cell pressures of the LVP chamber are significantly reduced after annealing at simultaneous high pressures and high temperatures,owing to the stress relaxation as accumulate in the LVP chamber.This acoustic travel-time method is verified to be a good way for precise determination of thermal(cell)pressures at high temperature conditions,and is of great importance and necessity to conduct in-situ physical property measurements under extreme high P-T conditions,especially when the precious synchrotron x-ray/neutron diffraction beams are not available.

STEAM和PRESS序列在脂肪肝定量诊断中应用价值的对比研究

目的比较STEAM和PRESS序列在脂肪肝定量诊断中的应用价值。方法选用45只健康新西兰大白兔,采用高脂高糖饲料加酒精饮料建立不同程度脂肪肝模型,采用STEAM和PRESS两种脉冲序列对同一位置、同一体素进行磁共振氢波谱扫描,共观察和测定9个指标,并逐一进行配对对照研究。结果经STEAM和PRESS两种定位方法测定,肝内水化学位移、脂肪化学位移、脂/水峰值比率、脂/水波峰下面积比率、脂肪百分比组间均数无显著性差异(P>0.05);而肝内水峰峰值、脂峰峰值、水波峰下面积、脂波峰下面积组间均数存在显著性差异(P<0.05),即STEAM序列下上述各指标均数明显低于PRESS序列,信号相对损失率平均约47.9%;且STEAM序列下各观测指标与脂肪肝病理分级的相关性普遍低于PRESS序列。结论PRESS较STEAM序列更适用于肝内脂肪含量的定量研究。

脑质子磁共振波谱检查PRESS与STEAM序列的对比

为比较PRESS与STEAM两种序列在脑部质子磁共振波谱分析 (1H MRS)临床应用和特征 ,挑选 2 45 1岁的成年人 2 0名进行1H MRS检查 ,同一位置、同一体素采用PRESS和STEAM两种脉冲序列采样 ,以水为内参照计算代谢物NAA ,Cr,Cho的浓度。结果显示 ,对PRESS和STEAM两种序列各代谢物浓度分别为 :N 乙酰天门冬氨酸 (NAA) :(13.74± 1.16 )mmol/L、 (12 .6 5± 2 .12 )mmol/L(P >0 .0 5 ) ;肌酸 (Cr) :(7.5 0± 0 .5 6 )mmol/L、(9.2 8± 1.44 )mmol/L(P <0 .0 5 ) ;胆碱 (Cho) :(1.43± 0 .2 2 )mmol/L、(1.5 9± 0 .35 )mmol/L(P >0 .0 5 )。只有Cr在两组之间差异具有显著性意义 ,其差别的来源主要是水抑制不充分和T1饱和所致。本研究表明PRESS和STEAM序列在脑的1H MRS检查具有一致性 ,但是又各具特征 ,为1H MRS的临床应用提供了脉冲优化选择背景。

IPSe.max Press铸瓷嵌体修复后牙牙体缺损的临床效果评价

目的对后牙邻面洞采用IPSe.maxPress铸瓷嵌体修复后的临床观察和分析,评价铸瓷嵌体修复牙体缺损的临床效果.方法 36例患者制作IPSe.maxPress铸瓷嵌体36个,修复2 a后用改良瑞格(Ryge)标准评价方法,对瓷嵌体的各项临床指标:瓷表面质地、边缘适合性、颜色匹配、牙龈反应、术后敏感及存留率进行观察分析.结果 IPSe.maxPress铸瓷嵌体存2a存留率为92.7%;92%具有良好的边缘适合性;12.3%患者有牙龈探诊出血;17%的患者备牙后有冷热敏感症状,13.8%粘结后0.5 a内消失;100%的患者对颜色满意.结论 IPS e.max Press铸瓷嵌体是一种较为可靠、效果较好的后牙牙体缺损修复体.

IPS e.max Press铸瓷嵌体修复磨牙髓室底穿孔的体外研究

目的:探讨IPS e.max Press铸瓷嵌体修复髓室底穿孔的操作步骤及形态恢复与封闭效果。方法:38个人恒磨牙用#8球钻在髓底中央制备髓底穿孔模型,随机均分A、B 2个实验组;4个人恒磨牙只开髓不制备髓底穿孔为C组作阴性对照。A、B 2组分别用IPS e.max Press铸瓷嵌体和间接树脂嵌体修复髓底穿孔,并使用树脂加强型玻璃离子进行黏结。从A、B 2个实验组中各随机选4个用SEM观察黏结界面,其余15个样本用葡萄糖氧化酶-蒽酮法检测微渗漏。结果:A组微渗漏值低于B组,但无统计学差异(P>0.05),两组对根分叉外形修复均达到了良好效果,但SEM观察A组的间隙宽度明显小于B组。结论:IPS e.max Press铸瓷嵌体修复磨牙髓室底穿孔在形态学和封闭性方面优于树脂嵌体。

IPS e.max Press全瓷冠用于前牙修复：边缘适合度及颜色匹配随访

背景:IPS e.max Press热压铸全瓷以其较好的美观效果和生物学性能已被越来越多地应用于临床修复。目的:分析IPS e.max Press全瓷冠用于前牙美学修复的边缘适合度及颜色匹配等情况。方法:纳入前牙美容修复患者52例(138颗牙),其中男20例,女32例,年龄18-45岁,前牙缺损62颗,牙外伤46颗,畸形小牙30颗,分为2组修复,治疗组(n=26)采用IPS e.max Press全瓷冠和传统钴铬合金烤瓷冠修复,对照组(n=26)采用传统钴铬合金烤瓷冠修复,修复后1周复诊,调查患者满意度;修复后随访6个月、2年,评估修复体完整性、边缘适合度、牙龈健康状况及颜色匹配等情况。结果与结论:修复后1周,治疗组患者对修复体颜色、外形及舒适度方面的满意度显著高于对照组(P<0.05);治疗后6个月,治疗组边缘适合度、牙龈健康状况及颜色匹配显著优于对照组(P<0.05);治疗后2年,治疗组边缘适合度、牙龈健康状况及颜色匹配显著优于对照组(P<0.05)。表明IPS e.max Press全瓷冠修复前牙具有良好的边缘适合度、牙龈健康状况及颜色匹配等生物学特性,患者满意度高。