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简介：Basedontheinvestigationofthefourdifferentcompositiondentalamalgamal-loysmadebysametechnologricalprocess,therelationbetweenphysicalpropertiesandmicrostructureofthemhasbeendiscussedindetail.Thetheoryfoundationhasbeenexaminedforthedesignofdentalamalgamalloy.Themainconclusionsareasfollows:

简介：Afreeelectronlaser(FEL)withitscharacteristicsofwidewavelengthtunability,ultrashortpulsetimestructure,andhighpeakpowerdensityispredominantlysuperiortoallotherconventionallasersinapplications.Severalexperimentalstudiesonmid-infraredFELirradiationondentalenamelanddentinewereperformedattheBeijingFEL.EXperimentalaimsweretoinvestigatechangesinthehardness,ratiosofPtoCaandCsbeforeandafterirradiationonsampleswithacharateristicabsorptionwavelengthof9.66μm,inthecolorsofthesesamplesurfacesafterirradiationwithdifferentwavelengthsaroundthepeakwavelength.ThetimedependenceoftemperatureofthedentinesamplewasmeasuredwithitspspulseeffectscomparedtothatwithacontinuousCO2laser.FTIRabsorptionspectraintherangeof2.5-15.4μmforsamplesoftheseharddentalsubstancesandpurehydroxyapatitewerefirstexaminedtodecidtheirchemicalcomponentsandabsorptionmaximums.Primaryexperimentalresultewillbepresented.2001ElsevierScienceB.V.Allrightsreserved.

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简介：Toquicklyobtainaccurate3Ddataofdentalcastmodel,thispaperproposesa3Dreconstructionmethodfordentalcastmodelbasedonstructuredlight.Thismethodcombinesthestructuredlightwiththemotorturntabletoobtainagroupof3Ddataforthedentalcastmodelfrommultipleangles,andautomaticallyregistersthedental3Ddatafrommultipleanglesthroughtheballcalibrationofturntable.Comparedwiththerealdataofthedentalcastmodel,themaximumerrorofthe3Dreconstructionresultsinthispaperis0.115mm.Thereconstructiontimeofthisprocessisabout130s.Theexperimentalresultsshowthatthemethodhashighprecisionandhighscanningspeedforthe3Dreconstructionofthedentalcastmodel.

简介：Objectives:Polymerizationshrinkageofdentalcompositesremainsamajorconcerninrestorativedentistrybecauseitcanleadtomicro-crackingofthetoothanddebondingatthetooth-restorationinterface.Theaimofthisstudywastomeasurethefull-fieldpolymerizationshrinkageofdentalcompositesusingtheopticaldigitalimagecorrelation(DIC)methodandtoevaluatehowthemeasurementisinfluencedbythefactorsinexperimentsetupandimageanalysis.Methods:Fourcommercialdentalcomposites,PremiseDentine,Z100,Z250andTetricEvoCeram,weretested.Compositewasfirstplacedintoaslotmouldtoformabarspecimenwithrectangular-sectionof4mmmm,followedbythesurfacepaintingtocreateirregularspeckles.Curingwasthenappliedatoneendofthespecimenwhiletheotherpartwerecoveredagainstcuringlightforsimulatingtheclinicalcuringconditionofcompositeindentalcavity.Thepaintedsurfacewasrecordedbyacharge-coupleddevice(CCD)camerabeforeandaftercuring.Subsequently,thevolumetricshrinkageofthespecimenwascalculatedwithspecialistDICsoftwarebasedonimagecrosscorrelation.Inaddition,afewfactorsthatmayinfluencethemeasuringaccuracy,includingthesubsetwindowsize,specklesize,illuminationlightandspecimenlength,werealsoevaluated.Results:ThevolumetricshrinkageofthespecimengenerallydecreaseswithincreasingdistancefromtheirradiatedsurfacewithaconspicuousexceptionbeingthecompositePremiseDentineasitsmaximumshrinkageoccurredatasubsurfacedistanceofabout1mminsteadoftheirradiatedsurface.Z100hadthegreatestmaximumshrinkagestrain,followedbyZ250,TetricEvoCeramandthenPremiseDentine.Largersubsetwindowsizemadetheshrinkagestraincontoursmoother.Butthecostwasthatsomedetailsintheheterogeneityofthematerialwerelost.Verysmallsubsetwindowsizeresultedinalotofnoiseinthedata,makingitdifficulttodiscernthegeneralpatterninthestraindistribution.Speckle

简介：thehydroxya-patite粒子的机械性质上的水吸着的损坏效果增强了Bis-GMA/TEGDMA共聚物(HA/Bis-GMA/TEGDMA)用3D被预言了有限房间模型。聚合物矩阵上的可塑剂效果被看作它的幼仔的模量的一个变化。三个不同房间模型被用来决定在debondingdamage上改变粒子内容，分裂期间力量和潮湿集中的影响。压力分发模式被检验了，压力转移模式澄清了。幼仔Bis-GMA/TEGDMA的模量和破裂力量合成也有或没有损坏的考虑用模型被预言。有thedebonding损坏的考虑的以前的结果在对存在文学的好同意是试验性的数据。我们的建议模型和一条其他的途径的防护效果被讨论。FCC房间模型也被扩大了预言批评负担为损坏并且undamaged合成题目到3点曲折测试。

简介：Thepurposeofthisstudywastouseathree-componentphotoinitiationsystemcomprising1wt%CQ(camphorquinone),2wt%DMAEMA(2-(dimethylamino)ethylmethacrylate)and2wt%Ph2I+PF6-(diphenyliodoniumhexafluorophosphate)toinitiatethecopolymerizationofthematrixresinswhichcombinebisphenol-S-bis(3-methacrylate-2-hydroxypropyl)ether(BisS-GMA)withtheexpandingmonomerunsaturatedspiroorthoesters2-methylene-1,4,6-trispiro[4,4]nonane(MTOSN),forminimizingthevolumetricshrinkagethatgenerallyoccursduringpolymerization.ItwashypothesizedthatMTOSNwouldexpandvolumetricallyduringpolymerizationunderthethree-componentphotoinitiatorsystemandfurtherreductionsinvolumetricshrinkagewouldbeobtained.Theperformancestudywhichconsistsofdegreeofconversionandconditionofthering-openingreactionsofMTOSN,volumetricshrinkageandmechanicalpropertiesincludingtensilebondstrength,compressivestrengthandVicker'shardnesswerecarriedoutrespectivelybyFouriertransferinfrared,thedilatometerandtheuniversaltestingmachine.Theresultssupportedthatthedentalcompositesbasedontheexpandingmonomerandthree-componentphotoinitiatorsystemengenderedagreaterdecreaseofvolumetricshrinkageandbettermechanicalproperties.

简介：2'-methacryloxy-3α,7α12α-trimethacryloylcholicacidethylester(CAGE4MA)hasbeenpreparedfromcholicacid.Photo-polymericresinswerepreparedfromCAGE4MA.2,2-bis[4-(2-hydroxy-3-methacrylyloxypropoxy)phenyl]propane(bis-GMA)wasusedforcomparison,triethyleneglycoldimethacrylate(TEGDMA)wasusedasdiluent.Thepolymerizationwasinitiatedbycamphoroquinone(CQ)/N,N-dimethylaminoethylmethacrylate(DMAEMA)system.TheconversionofCAGE4MAwas39%whenthereactiontimeis60s,whichislowerthanbis-GMAandTEGDMA.TheswellingvalueofCAGE4MAresinwas0.41%indistilledwater,whichismuchlowerthanthoseofbis-GMAresin(2.04%)andTEGDMAresin(4.77%)underthesameconditions.CopolymersfromCAGE4MAandTEGDMAhavebeenprepared.WiththeincreaseofTEGDMAinmixture,thedegreeofconversionofCAGE4MAandswellingvalueincreased.Theswellingvaluesofphotocuredresinsin0.1mol/LHClwerealsomeasured.

简介：这个工作的目的是用电气化学的技术，光显微镜学，扫描电子显微镜学(SEM)，和精力与氟化物离子在酸的人工的口水为牙齿的应用学习Ti-6Al-4V合金的降级行为散的spectrometry(版本)。试验性的结果证明那个氟化物离子在Ti-6Al-4V合金的降级上有重要影响，并且有氟化物离子(大约0.1wt%)的明显的批评集中。与增加氟化物离子集中，腐蚀潜力(E合金的corr)移动了向否定并且同时，合金的阻抗减少了到严重pitting腐蚀的从最小的腐蚀的显著转变在跟随TiO2的溶解的合金表面上被观察被动电影，导致合金的腐蚀抵抗的减少。TiO2的电气化学的溶解被动电影包含了氟化物原子的亲核的攻击到TiO2的钛原子。另外，在酸的口水的Ca2+和Na+可以包含表面反应并且使反应更复杂。

简介：摘要目的探讨锥形束CT下Invivo-dental软件辅助设计模拟种植上颌牙列缺损的临床效果。方法手机6名上颌牙出现缺损的患者，实施手术两年后复诊患者没有肿物情况。针对患者的上颌缺损部位实行CT奥妙后得到相应的DICT数据，随后将数据导入在Invivo-dental软件三维重建，测量修复重建后的下颌骨宽和高，通过导航技术对种植体的最佳植入位置和深度进行模拟，选择最合适的种植系统，设计出辅助制作种植导板，通过导板作用实现精确种植。结果术后半年进行观察，6名患者的种植体骨实现了良好的结合，术后种植支持固定义齿修复，达到了良好的咬合关系，患者对面型的恢复较为满意，其中一名庁后磨牙区的牙龈红肿疼痛，实施局部冲洗和抗炎1周后，炎症减轻，两周后肿胀消失，颜色恢复正常。结论使用CT下Invivo-dental软件辅助设计模拟种植，可以对上颌骨的下行缺损自体骨移植中的骨量，实现种植位置的进一步精确，并且辅助上颌骨在缺损后的种植和修复。