口腔解剖生理学之国外--MANDIBULAR FIRST PREMOLAR(下颌4)ppt课件

口腔解剖生理学之国外PPT MANDIBULARFIRSTPREMOLAR 下颌4 1 MANDIBULARFIRSTPREMOLAR Prof A El Sahn 口腔解剖生理学之国外PPT MANDIBULARFIRSTPREMOLAR 下颌4 2 CHRONOLOGY Prof A El Sahn 口腔解剖生理学之国外PPT MANDIBULARFIRSTPREMOLAR 下颌4 3 BuccalAspect Thegeometricaloutlineofthecrownisroughlytrapezoidalwiththeshortestoftheunevensidesiscervically Themesialanddistaloutlinesareslightlyconcavefromthecervixtothecontactareas Prof A El Sahn TheCrown 口腔解剖生理学之国外PPT MANDIBULARFIRSTPREMOLAR 下颌4 4 Themesialanddistalcontactareasarenearlyatthesamelevelinthemiddlethird justocclusaltothemiddleofthecrown Thecurvatureofthedistalcontactareaisbroaderthanthatofthemesialone Prof A El Sahn BuccalAspect TheCrown Contactareas 口腔解剖生理学之国外PPT MANDIBULARFIRSTPREMOLAR 下颌4 5 Thebuccalcuspislongandsharp andlooksmuchlikeamaxillarycaninefromthebuccalaspect Thetipofthebuccalcuspis inmostcases locatedalittlemesialtothecenterofthecrownbuccally similartothemandibularcaninetoagreaterdegree Prof A El Sahn BuccalAspect TheCrown Occlusaloutline 口腔解剖生理学之国外PPT MANDIBULARFIRSTPREMOLAR 下颌4 6 Thebuccalcuspislongerandmorepointedthatthebuccalcusponmandibularsecondpremolars Prof A El Sahn BuccalAspect TheCrown TheCrown 口腔解剖生理学之国外PPT MANDIBULARFIRSTPREMOLAR 下颌4 7 Themesialcuspridgeisshorterthanthedistalcuspridges Eithercuspridges orslopes usuallyshowshallownotches concavities ofunwornteeth Prof A El Sahn BuccalAspect TheCrown 口腔解剖生理学之国外PPT MANDIBULARFIRSTPREMOLAR 下颌4 8 Thenotchesonthemesialcuspridgesaremorepronounced ThesenotchesserveasspillwaysforfoodduringmasticationandaresometimescalledThomasnotches D M Prof A El Sahn 口腔解剖生理学之国外PPT MANDIBULARFIRSTPREMOLAR 下颌4 9 Morphologyofthebuccalsurface Thebuccalsurfaceofthecrownismarkedlyconvex morethaninmaxillarypremolars especiallyatthecervicalandmiddlethirds Prof A El Sahn BuccalAspect TheCrown TheCrown 口腔解剖生理学之国外PPT MANDIBULARFIRSTPREMOLAR 下颌4 10 Thereisacontinuousridgefromthecervicalmargintothecusptip whichiscalledthebuccalridge itisnotasprominentasthatonthemaxillaryfirstpremolar Prof A El Sahn BuccalAspect TheCrown 口腔解剖生理学之国外PPT MANDIBULARFIRSTPREMOLAR 下颌4 11 Verticaldevelopmentaldepressionsareoftenseenintheocclusalthirdofthebuccalsurfaceoneithersideofthebuccalridge betweenthethreebuccallobes Prof A El Sahn BuccalAspect TheCrown 口腔解剖生理学之国外PPT MANDIBULARFIRSTPREMOLAR 下颌4 12 Cervically thecrownisnarrowermesio distallythanatthecontactareas Prof A El Sahn BuccalAspect TheCrown 口腔解剖生理学之国外PPT MANDIBULARFIRSTPREMOLAR 下颌4 13 Thecervicalline Isslightlyconvextowardstheroot Prof A El Sahn BuccalAspect TheCrown 口腔解剖生理学之国外PPT MANDIBULARFIRSTPREMOLAR 下颌4 14 Theapicalthirdoftherootisoftenbentdistallyandsometimesmesially Therootofthistoothisshorterthanthatofthelowercanine Prof A El Sahn BuccalAspect TheRoot Thesinglerootisconvexonitsbuccalsurfaceandtapersgraduallytoanear lypointedapex D M 口腔解剖生理学之国外PPT MANDIBULARFIRSTPREMOLAR 下颌4 15 TheLingualAspect Thecrowntaperslingually sothelingualsideisnarrowerthanthebuccalside Prof A El Sahn TheCrown 口腔解剖生理学之国外PPT MANDIBULARFIRSTPREMOLAR 下颌4 16 Thelingualcuspisalwayssmall short reachingabouttwo thirdsthelengthofthecrownandoftenhasapointedtip Prof A El Sahn TheLingualAspect TheCrown 2 3 口腔解剖生理学之国外PPT MANDIBULARFIRSTPREMOLAR 下颌4 17 TheLingualAspect TheCrown Muchoftheocclusalsurfaceofthistoothcanbeseenfromthelingualaspectbecauseoftheshortnessofthelingualcusp Prof A El Sahn 口腔解剖生理学之国外PPT MANDIBULARFIRSTPREMOLAR 下颌4 18 Themesialanddistaloutlinesareslightlyconcavebetweenthecervicallineandthecontactareas Thecontactareasandmarginalridgesarepronouncedandextendoutabovethenarrowcervicalportionofthecrown Prof A El Sahn TheLingualAspect TheCrown 口腔解剖生理学之国外PPT MANDIBULARFIRSTPREMOLAR 下颌4 19 Thetipofthelingualcuspisinalignmentwiththetriangularridgeofthebuccalcusp Themesialanddistalocclusalfossaeareoneachsideofthetriangularridge Prof A El Sahn TheLingualAspect TheCrown D M 口腔解剖生理学之国外PPT MANDIBULARFIRSTPREMOLAR 下颌4 20 Thereisamesio lingualdevelopmentalgrooveseparatingthemesialmarginalridgefromthemesialslopeofthesmalllingualcusp Thisgrooveactsasalineofdemarcationbetweenthemesio buccallobeandthelinguallobeandextendsintothemesialfossaoftheocclusalsurface Prof A El Sahn TheLingualAspect TheCrown D M 口腔解剖生理学之国外PPT MANDIBULARFIRSTPREMOLAR 下颌4 21 Thecervicalportionofthecrownlinguallyisnarrowandconvex Thecervicallineisslightlyconvextowardstheroot Prof A El Sahn TheLingualAspect TheCrown Cervically 口腔解剖生理学之国外PPT MANDIBULARFIRSTPREMOLAR 下颌4 22 TheRoot Therootismuchnarroweronthelingualsurfacethanonthebuccalsurface Ittapersfromthecervixtoapointedapex Prof A El Sahn TheLingualAspect 口腔解剖生理学之国外PPT MANDIBULARFIRSTPREMOLAR 下颌4 23 TheMesialAspect Thegeometricoutlineofthecrownproximallyisroughlyrhomboidalasallmandibularposteriorteeth Prof A El Sahn TheCrown 口腔解剖生理学之国外PPT MANDIBULARFIRSTPREMOLAR 下颌4 24 Thecrownistiltinglinguallymuchmorethananyotherpremolar So thetipofthebuccalcuspisnearlycenteredovertheroot Prof A El Sahn TheMesialAspect TheCrown L L 口腔解剖生理学之国外PPT MANDIBULARFIRSTPREMOLAR 下颌4 25 Thelingualcuspisshorterthanthebuccalcuspbyaboutonethirdofthecrownlength whichisfromthecervicallinebuccallytothetipofthebuccalcusp TheCrown TheMesialAspect B Prof A El Sahn 口腔解剖生理学之国外PPT MANDIBULARFIRSTPREMOLAR 下颌4 26 Thetipoftheshortlingualcuspisusuallyinlineverticallywiththelingualborderofthecervicalportionoftheroot Thisdiffersfromtheconditionfoundinmaxillaryposteriorteeth wherebothbuccalandlingualcusptipsarewellwithintheconfinesoftheroottrunks Prof A El Sahn TheMesialAspect TheCrown 口腔解剖生理学之国外PPT MANDIBULARFIRSTPREMOLAR 下颌4 27 Thelingualcusp beingshort andnarrowmesio distally isanonfunctioningcusp Prof A El Sahn TheMesialAspect TheCrown 口腔解剖生理学之国外PPT MANDIBULARFIRSTPREMOLAR 下颌4 28 Thebuccaloutlineofthecrownisprominentlycurved thecrestofcurvatureisusuallyjustocclusaltothecervicalline nearthemiddlethirdofthecrown Prof A El Sahn TheMesialAspect TheCrown 口腔解剖生理学之国外PPT MANDIBULARFIRSTPREMOLAR 下颌4 29 Thelingualoutlineofthecrownisacurvedoutlineoflessconvexitythanthatofthebuccalsurface Thecrestofcurvatureisaboutinthecenterofthecrownlengthnotfarfromthetipofthelingualcusp Prof A El Sahn TheMesialAspect TheCrown 口腔解剖生理学之国外PPT MANDIBULARFIRSTPREMOLAR 下颌4 30 Thelingualsurfaceofthecrownextendslinguallybeyondthelingualsurfaceoftherootduetoextremelingualtiltingofthecrownmakingalingualoverhangabovetherootlingually Prof A El Sahn TheMesialAspect TheCrown 口腔解剖生理学之国外PPT MANDIBULARFIRSTPREMOLAR 下颌4 31 Thetriangularridgeofthebuccalcuspinclinessharplyfromthecusptiptowardthecenteroftheocclusalsurface whilethetriangularridgeofthelingualcuspisshortandisinanearlyhorizontalplane Prof A El Sahn TheMesialAspect TheCrown OcclusalOutline 口腔解剖生理学之国外PPT MANDIBULARFIRSTPREMOLAR 下颌4 32 Themesialmarginalridgeinclinessharplyfromthebuccaltothelingualsurfaceinacervicaldirectionandisnearlyparalleltothetriangularridgeofthebuccalcusp Prof A El Sahn TheMesialAspect TheCrown OcclusalOutline 口腔解剖生理学之国外PPT MANDIBULARFIRSTPREMOLAR 下颌4 33 Themesialmarginalridgeisshorterandusuallylocatedmorecervicallythanisthedistalmarginalridge Thisistheonlyposteriortoothinwhichthisistrue Prof A El Sahn TheMesialAspect TheCrown OcclusalOutline D M 口腔解剖生理学之国外PPT MANDIBULARFIRSTPREMOLAR 下颌4 34 Whenpresent themesio lingualdevelopmentalgroovebetweenthelingualborderofthemesialmarginalridgeandthemesialslopeofthelingualcusp inthelingualthirdofthecrown Prof A El Sahn TheMesialAspect TheCrown OcclusalOutline 口腔解剖生理学之国外PPT MANDIBULARFIRSTPREMOLAR 下颌4 35 ThecervicallineisconvexocclusaIIy Thecrestofcurvatureiscenteredbucco linguaIIy Themesialcurvatureaveragedabout1mm However thecervicallinemaybestraightacrossbucco lingually andisinamoreocclusalpositionlinguallythanbuccallybyabout2mm Prof A El Sahn TheMesialAspect TheCrown 口腔解剖生理学之国外PPT MANDIBULARFIRSTPREMOLAR 下颌4 36 Thesurfaceofthecrownmesiallyissmoothexceptforthemesio lingualgroove Thesurfaceisconvexatthemesialcontactarea Prof A El Sahn TheMesialAspect TheCrown MorphologyoftheMesialsurface 口腔解剖生理学之国外PPT MANDIBULARFIRSTPREMOLAR 下颌4 37 Immediatelybelowtheconvexityofthecontactarea thesurfaceissharplyconcavetillthecervicalline Themesialcontactareaiscenteredonalinewiththetipofthebuccalcuspandalittleocclusaltothemiddleofthecrownlength Prof A El Sahn TheMesialAspect TheCrown MorphologyoftheMesialsurface 口腔解剖生理学之国外PPT MANDIBULARFIRSTPREMOLAR 下颌4 38 TheRoot Thebuccalandlingualsidesoftherootarenearlystraightinthecervicalhalf Thentherootoutlinetapersapicallytoabluntapex Therootapexisinlinewiththetipofthebuccalcusp Prof A El Sahn TheMesialAspect B 口腔解剖生理学之国外PPT MANDIBULARFIRSTPREMOLAR 下颌4 39 Themesialsurfaceoftherootissmoothandflatwithalongitudinaldeepdevelopmentalgrooveinthemiddleandapicalthirds Shallowgroovesmaybeevidence Prof A El Sahn TheMesialAspect TheRoot 口腔解剖生理学之国外PPT MANDIBULARFIRSTPREMOLAR 下颌4 40 Occasionallytheapicalthirdoftherootmaybedividedintoabuccalandlingualportionbyadeepdevelopmentalgrooveendinginthebifurcation i e themandibularfirstpremolarwillhaveabifurcatedroot Prof A El Sahn TheMesialAspect TheRoot 口腔解剖生理学之国外PPT MANDIBULARFIRSTPREMOLAR 下颌4 41 M D Prof A El Sahn TheCrown TheDistalAspect Thegeneralshaperesemblesthatofthemesialaspect 口腔解剖生理学之国外PPT MANDIBULARFIRSTPREMOLAR 下颌4 42 DistalmarginalridgeisThelongerbucco linguallyandisinamorehorizontalpositionthanthemesialone itisnearlyatrightangletotheaxisofthetooth Prof A El Sahn TheDistalAspect TheCrown 口腔解剖生理学之国外PPT MANDIBULARFIRSTPREMOLAR 下颌4 43 Thedistalmarginalridgeishigherormoreocclusallylocatedthanthemesialmarginalridge whichisauniquecharacteristicofthistooth D M Prof A El Sahn TheDistalAspect TheCrown 口腔解剖生理学之国外PPT MANDIBULARFIRSTPREMOLAR 下颌4 44 Usuallythereisnodevelopmentalgroovebetweenthedistalmarginalridgeandthedistalslopeofthelingualcusp Prof A El Sahn TheDistalAspect TheCrown 口腔解剖生理学之国外PPT MANDIBULARFIRSTPREMOLAR 下颌4 45 ThecervicallineDistallymaybelesscurvedthanonthemesial ItmayslopeoccIusallyfrombuccaltolingualasitdidonthemesialbyabout2mm D M Prof A El Sahn TheDistalAspect TheCrown 口腔解剖生理学之国外PPT MANDIBULARFIRSTPREMOLAR 下颌4 46 Thedistalsurfaceofthecrownissmoothlyconvex Alinearconcavityextendsbucco linguallyjustabovethecervicalline Prof A El Sahn TheDistalAspect TheCrown 口腔解剖生理学之国外PPT MANDIBULARFIRSTPREMOLAR 下颌4 47 Thedistalcontactareaisbroaderthanthemesial Thecenterofthedistalcontactareaisatapointmidwaybetweenbuccalandlingualcrestsofcurvatureandmidwaybetweenthecervicallineandthetipofthebuccalcusp Thedistalcontactareaismorelinguallysituatedthanthemesialone Prof A El Sahn TheDistalAspect TheCrown 口腔解剖生理学之国外PPT MANDIBULARFIRSTPREMOLAR 下颌4 48 Thesurfaceoftherootdistallyshowsmoreconvexitythanmesially Ashallowdevelopmentaldepressioniscenteredontheroot whichmaycontainalongitudinaldevelopmentalgroovelessmarkedthanmesially M D Prof A El Sahn TheRoot TheDistalAspect 口腔解剖生理学之国外PPT MANDIBULARFIRSTPREMOLAR 下颌4 49 Usualdifferencesbetweenthemesialanddistalaspects Thefrequentpresenceofamesio lingualdevelopmentalgroove Thedifferenceintheslope length andheightofthemarginalridges Thelongitudinaldevelopmentalgrooveonthemesialsurfaceoftherootismoremarkedthanonthedistalsurface D M Prof A El Sahn 口腔解剖生理学之国外PPT MANDIBULARFIRSTPREMOLAR 下颌4 50 TheOcclusalAspect Theocclusalaspectsoflowerfirstpremolarshowmuchvariationinthegrossoutline Becauseoflingualinclinationofthiscrownovertheroot mostofthebuccalsurfacemaybeseenfromtheocclusalaspect whereaslittleofthelingualsurfaceisinview Prof A El Sahn TheCrown 口腔解剖生理学之国外PPT MANDIBULARFIRSTPREMOLAR 下颌4 51 Theusualoutlineformisroughlydiamond shaped orroughlycircular Prof A El Sahn TheOcclusalAspect TheCrown 口腔解剖生理学之国外PPT MANDIBULARFIRSTPREMOLAR 下颌4 52 Theproximalsidesconvergesharplyfromthecontactareastothecenterofthelingualsurface Themesialoutlineofthecrownisflatorslightlycurved Thedistalcrownoutlineismoreconvex Prof A El Sahn TheOcclusalAspect TheCrown L L 口腔解剖生理学之国外PPT MANDIBULARFIRSTPREMOLAR 下颌4 53 Thecontactareasocclusallyarerepresentedbycurvaturesjustlingualtothebuccallineangles Theyarerelativelybroad thedistalareaisbroaderthanthemesialcontactarea Prof A El Sahn TheOcclusalAspect TheCrown 口腔解剖生理学之国外PPT MANDIBULARFIRSTPREMOLAR 下颌4 54 Thebuccalcuspisverymuchlargerthanthelingualcuspanddominatestheocclusalsurface Prof A El Sahn TheOcclusalAspect TheCrown L B 口腔解剖生理学之国外PPT MANDIBULARFIRSTPREMOLAR 下颌4 55 Theocclusalsurfaceshowsalongbuccaltriangularridgeandashortlingualtriangularridge Prof A El Sahn TheOcclusalAspect TheCrown L L B B 口腔解剖生理学之国外PPT MANDIBULARFIRSTPREMOLAR 下颌4 56 Thetwotriangularridgesoftenuniteandformatransverseridge Oneachsideofwhichthereisafossa themesialanddistalocclusalfossae Prof A El Sahn TheOcclusalAspect TheCrown L B 口腔解剖生理学之国外PPT MANDIBULARFIRSTPREMOLAR 下颌4 57 Sometimesthetransverseridgeiscrossednearthecenteroftheocclusalsurfacebyashallowcentralgroove whichextendsfromthemesialtothedistalfossa Prof A El Sahn TheOcclusalAspect TheCrown 口腔解剖生理学之国外PPT MANDIBULARFIRSTPREMOLAR 下颌4 58 Well markedmesialanddistalmarginalridgesareseenocclusalIyboundingthemesialanddistalfossae Themesialanddistalocclusalfossaearetwodepressionscorr