PAGE1PAGE5UnitSevenProsthodonticMaterialsProsthodonticmaterialscanberoughlydividedintothefollowing8groups.(l)Impression(2)Modelmaterials(Gypsum,waxes)(3)Investments(4)Metalsandalloys(5)Ceramicandmetal-bondedceramics(6)Syntheticpolymers(Denturebasepolymers,dentureliningmaterials,artificialteeth)(7)Dentalcements(8)Abrasionandpolishingmaterialsetc.Manydentalappliancesareconstructedoutsidethepatient'smouthonmodelsofthehardand/orsofttissues.Theimpressionstageisthefirstofmanystagesinvolvedintheproductionofdentures,crowns,bridges,orthodonticappliancesetc.Impressionmaterialscanbecategorizedaseitherrigidorelasticwhenset.Therigidornon-elasticmaterialsincludeimpressionplaster,impressioncompound,andimpressionwaxandzincoxide/eugenolimpressionpaste.Thefactor,whichlinksthesematerials,istheirinabilitytoaccuratelyrecordundercuts.Impressioncompoundandimpressionwaxesarethermoplasticmaterials.Theelasticimpressionmaterialscanbedividedintotwogroups,thehydrocolloidsandtheelastomers.Thehydrocolloidimpressionmaterialsarebestusedforobtaininganaccuratereproductionoftoothform,includingtheundercutsandinterproximalspaces.Thehydrocolloidscanbesub-dividedintothereversible,agar-basedmaterials,andtheirreversible,alginate-basedmaterials.Theyarehydrophilicanddonotrecoilwhentheycomeintocontactwithpocketsofsalivaorblood.Reversiblehydrococolloidsareviscoelasticmaterials.Theprimaryusesofagarimpressionarefordentureandcrownandbridgespatients.Alginateimpressionmaterialsarewidelyusedforavarietyofapplications,suchasedentulousandpartiallyedentulousarches.Syntheticelastomersarecommonlyusedforcrownandbridgeimpressions,sincetheyhavebettertearresistanceanddimensionalstabilitythanhydrocolloids.Fourtypesofelastomersareingeneraluse,polysulphides,siliconerubbers(condensationcuringtype),polyethers.After"setting",theimpressionisremovedfromthepatient'smouth,themorphologyofthehardandsofttissuesisrecordedintheimpression,thenmodelsanddiescanbepreparedusinggypsummodelanddiematerials.Gypsumproductsusedindentistryarebasedoncalciumsulphatehemihydrate[(CaSO4)2.H2O].Followingtheproductionofastonemodelordie,thenextstageintheformationofmanydentalappliances,denturesorrestorationsistheproductionofawaxpatternoftheapplianceonthemodelusingpatternwaxes(modelingandinlaywaxes).Thenextstageinvolvestheinvestmentofthepatterntoformamould.Thecommonlyusedinvestmentmaterialscanbereferredtoasgypsum-bondedorphosphate-bondedinvestments.Usingthelost-waxtechnique,thewaxisremovedtoleaveamould,whichcanbefilledwithanalloy,ceramicorapolymer.Theshapingofmetalandalloysfordentalusecanbeaccomplishedbycasting,coldworkingoramalgamationmethods.Goldcastingalloys,silver-palladiumcastingalloysareusedformakingcrowns,inlaysanddenturebases.Basemetalcastingalloyscontainnogold,silver,platinumorpalladium.Thetwomostcommonlyusedarenickel-chro-mium(Ni/Cr)alloywhicharecommonlyusedforpartialdentureframeworkcastings.Usingcoldworking,thewroughtalloysishammered,drawnorbentintoshapeattemperatureswellbelowtherecrystallizationtemperatureofthemetal.Steelandstainlesssteelarethemostwidelyusedwroughtalloys.Whencrownorbridgeisconstructedoutsidethepatient'smouth,theycanbefixedintoplaceusingacementlutingmaterial.Dentalcementscanbeusedascavitylining,lutingandendodontictreatment.Therearethreemaingroupsofdentalcements.(l)cementsbasedonphosphoricacid:zincphosphate,silico-phosphatecements.(2)cementsbasedonorganometallicchelatecompounds:zincoxide/eugenol,ortho-ethoxybenzoicacid(EBA),Calciumhydroxidecementsinwhichthearomaticligandsaresalicylates.(3)cementsbasedonpolyalkenoicacids:polycarboxylatecementsandglassionomer(polyalkenoate)cement.VOCABULARYl.impressionmaterial印模材料2.modelmaterial模型材料ormoldingmaterial3.gypsum生石膏plaster(熟)石膏又叫plasterofParisplasterstone生石膏4.investment包埋材料，包埋castinginvestment鑄造包埋材料5.metal-bondedceramic金屬烤瓷metallo-ceramicsystem金屬烤瓷體系6.syntheticpolymer合成聚合物7.denturebasepolymer義齒基托聚合物8.dentureliningmaterial義齒襯層材料9.dentalcement牙科水門汀10.abrasionandpolishingmaterial研磨材料11.set固化，凝固，硬化；凝固的12.impressionplaster印模石膏13.impressioncompound印模膏，印模膠，打樣膏14.impressionwax印模蠟15.zincoxide/eugenol氧化鋅丁香酚16.impressionpaste印模糊劑17.undercut倒凹18.hydrocolloid水膠體，水解膠體19.elastomer彈性體20.agar-basedimpressionmaterial瓊脂(基)印模材料21.alginate-basedimpressionmaterial藻酸鹽(基)印模材料22.hydrophyllic親水(性)的23.recoil退縮，反彈24.viscoelastic粘彈性的25.tearresistance抗撕裂性，抗撕裂力，抗撕裂強度26.dimensionalstability尺寸穩定性27.polysulphide聚硫化物，多硫化合物polysulfidebasedimpressionmaterial聚硫基印模材料28.siliconerubber硅橡膠siliconebasedimpressionmaterial聚硅基印模材料29.condensation縮合(聚)condensationpolymerization縮聚作用30.addition加成31.cure硫化，固化32.polyether聚醚polyetherbasedimpressionmaterial聚醚基印模材料33.morphology形態，表面幾何形態34.calciumsulphatehemihydrate(CaSO4)2.H2O半水硫酸鈣35.waxpattern蠟型，蠟鑄模36.patternwax鑄模蠟，模型蠟modellingwaxandinlaywaxcollectivelycalledpatternwax37.mould鑄型，鑄模castingmould鑄型，鑄模38.lost-waxtechnique失蠟技術39.casting鑄造40.coldworking冷加工41.amalgamation汞齊化，汞合，混合42.goldcastingalloy鑄造金合金43.silver-palladiumcastingalloy鑄造銀鈀臺金44.basemetalcastingalloy非貴金屬合金nobledentalalloy貴金屬合金45.platinum鉑，白金46.nickel-chromiumalloy鎳鉻合金47.cobalt-chromiumalloy鈷鉻合金48.wroughtalloy鍛造合金，鍛制49.cavitylining洞襯50.luting(orcementing)封閉，粘接，(用)泥封51.zincphosphatecement磷酸鋅水門汀52.silico-phosphatecement硅磷酸鹽水門汀53.copperphosphatecement磷酸銅水門汀54.organo-[詞頭]有機，器官organometallic有機金屬的，金屬有機的chelatecompound整(形化)合物organometallicchelatecompound有機金屬整合物，金屬有機整合物55.ortho-[詞頭]正，原ethoxy乙氧(基)benzo-[詞頭]苯benzoicacid苯(甲)酸，安息香酸ortho-ethoxybenzoicacidcement正-乙氧基苯甲酸水門汀56.calciumhydroxidecement氫氧化鈣水門汀57.aromaticligand芳香族配位體58.salicylate水楊酸鹽(酯)59.polyalkenoicacid聚烯酸60.polycarboxylatecement聚鞍酸水門汀61.glassionomercement玻璃離子水門汀62.polyalkenoate聚烯酸酯NOTES1．modeln．模型主要指用石膏制成的陽模2．mouldn．模型，鑄模，型主要指鑄造中失蠟后包埋材留下的模腔，是物體的陰模。3．patternn．模型，樣本，型，式樣dentalpattern牙型；waxpattern蠟型4．castn．模型，鑄造，鑄件(鑄造完成后得到的物件)5．castingn．鑄造，鑄件，鑄模，鑄造法agypsummodel→awaxpattern→aphosphate-bondedinvestmentmould→cast(lost-waxtechnique)→ametalcastorcastingcastn.(l)anactofcasting(2)areproduction(egofastatue)formedbycasting(3)animpressiontakenfromanobjectwithamoltenorplasticsubstance(4)amold_vt.(1)toshape(egmetalorplastic)bypouringintoamouldwhenmelten,tomould(2)toformbycastingvi.totakeforminamouldcastingn.(I)sth.castinmould(2)theactofcastingormolding,amouldmodeln.(l)areplicaofsth.inreliefor3dimensions,alsoarepresentationofsth.tobeconstructed(2)tobefoUowedinconstruction,sth.tobecopied;apatternv.(l)toplan