最新牙体牙髓病学概论 (NXPowerLite)课件PPT.ppt 310页

'牙体牙髓病学概论(NXPowerLite) Adisciplinetostudytheetiology,pathogenicmechanism,pathology,pathology-physiology,clinicalexpression,treatmentandfavorableturnetc.ofthediseaseondentalhardtissueandpulptissue.Concept ThecontentofthetextbookCariologyNon-cariogenicdiseaseofdentalhardtissueEndodonticsOperativedentistry Imagelikingcharacter(script)worm+tooth Thechinesewereknowntohavetreateddentalillswithknife,cautery,andacupuncture,atechniquewherebytheypunctureddifferentareasofthebodywithaneedle. InDynastyHan(A.D.215~282)TherearesomerecordaboutperiodontologyAnnoDomini PulpitisInHan,Mr.ZhangZhongJing《JinGuiYaolue》wasaveryfamouswritingsinwhichtherewasarecordaboutarsenicArsenicisatoxicantmedicinewhichhasbeengenerallyusedforkillingpulp InDynastyTang(A.D.7~10era)thepeopleusesilverpastetofilltoothdecay InTang,toothbrushwithwillowtwigatoothbrushwithhairplantedwasinventedinA.D.9~11centuryfromatombofanemperor`sson-in-lawofLiaofromChiFongcity 3eventsabovedescribedreflectedancientcivilizationofourcountry DentistrydevelopmentinWestcountry ThefirstknowndentistwasanEgyptiannamedHesi-re(3000B.C.).Hewaschieftoothisttothepharaohs,hewasalsoaphysician,indicatinganassociationbetweenmedicineanddentistry. TheGreeksHippocrates(500B.C.)appreciatedtheimportanceofteeth.Heaccuratelydescribedthetechniqueforreducingafractureofthejawandalsoreplacingadislocatedmandible.Hewasfamiliarwithextractionforcepsforthisismentionedinoneofhiswritings. Aristotle(384B.C.)alsostatedfigsandsoftsweetsproducedecay. Galen(200A.D.Romans)wasfirsttorecognizethattoothachecouldbe:PulpitisorpericementitisHealsoclassifiedteethintocentrals,cuspidsandmolars. B.LeonardodaVinci(endof15thCentury)-hedescribedtheanatomyofthejaws,teethandmaxillarysinus.Thesedrawingsarethefirsttoaccuratelydescribethemaxillarysinus.However,credithasbeengiventoDr.NathanielHighmoreofEngland(1650). D.Leeuwenhoek(17thCentury)-inventedthemicroscope.Hedescribedthedentaltubuliandwasthefirsttoseeorganismsofthemouth Antonvanleeuwenhoek K.JohnGreenwood(1789)-denturesforGeorgeWashingtonweremadebyhim. aredlaserscansGeorgeWashington"sfalseteethnotwoodenLaserscansfindgold,ivory,lead,humanandanimalteeth L.PierreFauchard(18thCentury-1728)-FatherofScientificDentistry.Wroteagreattext"SurgeonDentist".HealsowroteacompleteworkonOdontologyintwovolumes,843pages.Herecognizedtheintimaterelationshipbetweenoralconditionsandgeneralhealth.Headvocatedtheuseofleadtofillcavities.Heremovedalldecayandifthepulpwasexposed,heusedthecautery. Museed"ArtDentairePierreFauchardattheAcademieNationaledeChirurgieDentaire22RueEmileMenier,75116,ParisFrance Heprescribedoilofclovesandcinnamonforpulpitis.Hedescribedpartialdenturesandfulldenturesinhistext.Heconstructeddentureswithspringsandusedhumanteeth.Golddowelswereusedinrootcanalsfilledwithlead.HewasalsoknownasFatherofOrthodontics.Faucharddiedin1768attheageof83. 1763A.DJohnBaker,M.D.SurgeonDentist.TheearliestqualifieddentisttopracticeinBostonandinAmerica. 1836A.D.Arsenicintroducedforthekillingofpulps,bySpooner. 1840A.D.TheAmericanSocietyofDentalSurgeons,firstnationaldentalorganization.TheBaltimoreCollegeofDentalSurgery,thefirstschoolintheworldforthetrainingofdentistswasfoundedbyHarrisandHarden. FoundedbyHarrisandHarden 1859A.D.OrganizationofAmericanDentalAssociationonarepresentativebasis. 1890W.D.Millerproposeachemical-bacteriaParaorganismtheorytoexplainthemechanismofcaries 1891A.D.ExtensionforpreventionandscientificcavitypreparationpromulgatedbyG.V.Black.1892A.D.Theestablishmentofathree-yearcourseindentalcolleges. 1906A.D.Einhornrecommendsnovacaineandadrenalincombinationforlocalanesthesia. 1915A.D.McKayandBlackpublishresultsofinvestigationoffluorideindrinkingwater. 1956A.D.Air-rotordrill,250,000RPMDr.RobertBorden. StomatologyinChinabefore1949WestChinaUniversity(1910)ShanghaiSecondUniversity(1920)4thMilitaryMedicalUniversity(1935)BeijingUniversity(1943) ShanghaiSecondUniversityWestChinaUniversity1918(School1910) ThefirstdentalschoolinChinawasfoundedinWestChinaMedicalUniversityin1917.A.W.Lindsay A.W.Lindsaywasteaching After1949HubeiMedicalCollege1960FounderProf.XiaLiangCai Inrecent20years,thescienceandtechniquesgotgreatprogressThereare1~2facultiesordentalschoolsineachprovince CariesresearchCariesVaccineEtiology&preventionPulpdiseaseModernrootcanaltraitmentPulpbiologyStemcell–finaltargetAchievements Craniofacial-oral-dentalresearchinthecentury21st TheleadershipteamofNIDRinitiatedastrategicplanningprocessin1999toidentifyWhereweare(strengths,weaknesses,opportunitiesandthreats)Wherewewanttogo(e.g.,missionandvision)Howweplantogetthere(strategicplan) Severalscientificareaswillbeconcernedincentury21st Frommolecularbiologytoclinicalinvestigations;etiology,pathogenesis,epidemiology,prevention,diagnosisandtreatmentofinheritedcraniofacial-oral-dentaldiseasesanddisorders.e.g.,ectodermic,dysplasia,cleftlipandpalate,amelogenesisimperfect,dentingenesisimperfect,osteogenesisimperfect,andotherinheriteddiseases.Inheriteddiseaseanddisorders Hereditaryhypoplasia Hereditaryaplasiaoftheenamel dentalcariesPeriodontitisOralcandidiasisHerpesHepatitis,HIV/AIDSInfectionsdiseasesViral,bacterial,fungalandparasiticsuchas DiseasedPeriodontium Primaryherpeticstomatitis Candidalstomatitis NeoplasticdiseaseSupportsbasic,patientoriented,andcommunity-basedresearchontheetiology,pathogenesisandmetastasis,epidemiology,prevention,diagnosis,treatmentoforalandpharyngealneoplasticdiseases ChronicdisablingdiseasesThefullrangeofresearchinvolvingchronicdisablingdiseaseassociatedwiththecraniofacial-oral-dentalcomplex Thisincludesosteoporosis,osteoarthritisandrelatedbonedisorders,temporo-mandiblejointdiseasesanddisorders,neuropathiesandneuro-degenerativediseasesincludingthoseinvolvingoralsensoryandmotorfunctionsandautoimmunediseasessuchassjÖgrenssyndrome. Chronicdiseasesofcran-oral-dentalcomplexandothersystemicdiseases(e.g.,diabetes) Biomaterials,biomimeticsandtissueengineeringBiomaterialsusedfortherepair,regeneration,restorationandreconstructionofcraniofacial-oral-dentalmolecules,cells,tissuesandorgans Thestudyofcomputeraiddesign(CAD)computeraidmanufacture(CAM)fordenture Behavior,healthpromotionandenvironmentaimedatassessingtheinteractiverolesofsociological,behavior,economic,environmental,genetic,andbiomedicalfactorsincraniofacial-oral-dentaldiseasesanddisorders 1996—DietandOralHealth caries CariologyisadisciplinewithinStomatologywhichdealswiththecomplexinterplayingbetweentheoralfluidsandthemicrobialdepositsinrelationtosubsequentchangesinthedentalhardtissues. Epidemiologyindentalcaries Severalindexhavebeenusedindentalcaries Prevalence=NoofthepatientswithcariesNoofthespecificpopulationinanareaatriskofgettingcariesatthattimePrevalenceofcaries:thetotalcariesexperienceofapopulationinexistenceatacertaintimeinadesignatedarea. Cariesincidenceisusuallyexpressedasthenumberofnewdecayedteethorsurfacesper-aperiodinaindividual,group,orpopulation.Incidenceofcaries DMF=Decayedteeth+Missingteeth+Filledteeth/NumberofsubjectsexaminedDMFT Ifsurfacehavebeencounted,thenwerefertothescoreasDMF-SIftheteethhavebeencounted,thenitisrefertoasDMF-TTheDMF-SorDMF-Tareoftenreferredtoasan“index” Thedistributionofdentalcariesinoralcavity Reducingtendencyindevelopedcountry TheDMFTprevalenceof12-year-oldchildrenintheNordiccountriesintheperiod1974-91.Denmark,Finland,NorwayandSwedenseemtofollowthesamedownwardtrend,whereasIcelandhasstartedamorerapiddeclinesomewhatlater. Increasingtendencyindevelopingcountry 958498959892959813RomaniaChinaFujiTongaJordanian45627883858662DMFTsfor12Years-oldinPartofdevelopingcountry ThecariesprevalenceofChinaTimePopulationpeoplewithcariesprevalenceBefore1949324691925859.301950~195921931210678148.701960~196954470821777440.001970~19793766290135636236.0013134040.54permanentteethCities25080Countryside2063629.70Cities1968379.55Countryside1625358.48Deciduousteeth TheDMFTprevalenceof12-year-oldchildrenin11provincesofChinaBeijing1.410.98Shanghai1.170.95Tianjing1.411.02Gansu0.360.8Shandong0.690.59Yunnan0.460.88Liaoning0.761.29Zhejiang1.221.46Hubei0.980.51Guangdong0.911.65Sichuan0.570.37Account0.670.88ProvinceDMFT(1983)DMFT(1995) AgeDMFT121.03151.42181.6035~442.1165~742.49(DFT)TheDMFTprevalencein1995 Currentconceptofcariesetiology Dentalcariesisamultifactorialdiseaseinwhichthereisaninterplayofthreeprincipalfactors:thehost(primarilythesalivaandteeth),themicroflora,andthesubstrate,ordiet. Afourthfactortimemustbeconsideredinanydiscussionoftheetiologyofcaries.Diagrammatically,thesefactorscanbeportrayedasfouroverlappingcircles. Micro-organismshost&toothSub-strateThefourcirclesdiagrammaticallyrepresentthefactorsinvolvedinthecariousprocess.allfourfactorsmustactconcurrently(overlappingofthecircles)forcariestooccurtimenocariesnocariesnocariesnocariescaries Cariesrequiresasusceptiblehost,acariogenicoralfloraandasuitablesubstratethatmustbepresentforasufficientlengthoftime EtiologyofCaries Salivathetermsalivareferstothemixtureofsecretionsintheoralcarity SalivaisproduceddayandnightanditisconstantlyswallowedSalivaispresentasaproteinaceousfilmcoveringallsurfacesoforalcavity Thismixtureconsistsoffluidsderivedfromthemajorsalivaryglandsminorglandsoforalmucosetracesfromgingivalexudate EffectofdesalivationonincidenceandextentcariesinanimalsEffectofdesalivationoncariesinhamstersGruopNo.hamstersAvg.no.cariousteethAvg.cariesscoreIntactSalivaryglands202.34.0Desalivated*1010.539.0*Parotid,submandibular,andsublingualglands. DecreasedsalivaryflowandcariesinhumansSarcoidosisSjogren’ssyndromeTharapeuticradiation HydrogenionBufferingabilityCalciumInorganicphosphateFluoricleInorganiccomponents OrganiccomponentsmucinsGlycoproteinsStatherinandacidicproline-richproteinsamylase Antrmicrobialproteins Salivaanddentalcaries thequantityofsalivaassociatedwithcariesexperience RelationshipbetweensalivarycharacteristicsandcariesprevalencePropertyRelationshipPropertyRelationshipFlowrate±pHCa--Buffercapacity+PO4NH3AmylaseViscosityUrea----Salivarycompositionandcaries Antibacterialfactorsofglandularorigincouldprotectoralmucosalandhardsurfacesbyhelpingtoregulatethequantityandspeciesdistributionoforalmicrobes OralMicroorganismsanddentalplaque Incontrasttomucosalsurfaces,thesurfacesofteetharenotconstantlyrenewedbysheddingofcolonizedepithelialcells.Surfacesofteeth SomespecialsitesocclusalfissuesApproximalsurface DentaldepositsBiofilmsondentalsurface-matrix-embeddedmicrobialpopulation,adherenttoeachotherand/ortosurfaceorinterfaces AcquiredpellicleAcellular,homogeneousorganicfilmthatformsonenamelandotherhardsurfacebyselectiveadsorptionofsalivaryproteins. adsorptionofsalivaryproteinsorglycoproteinsOrigin Immediatelyaftercleaningandpolishing,salivarysecretedepositinthedefectsofenamel. SurfacepellicleSubsurfacepellicleHistologicalappearance ThesurfacepellicleappearsacellularandfaintlygranularunderTEMSurfacePellicle Pelliclesofunknownagemayvaryinthicknessfrom50~1000nm. globularfibrillargranularDifferentmorphologicaltypes Asubsurfacepellicleconsistingofdendriticprocessesthatspreadintotheintercrystallinespacesandextendto3µmintotheenamel. 90%water10%solidmaterialcomposition Accordingtochemicalanalysesaminoacidsaccountfor45%to50%carbohydratesamount10%to15%ofthedryweightlipid Functionhealing,repairing,orprotectingtheenamelsurfaceimpartingselectivepermeabilitytotheenamelinfluencingtheadherenceofspecificoralmicroorganismstothetoothsurfaceservingasasubstrateornutrientfortheorganisms summaryOrganicdepositNaturallyformsbyselectiveadsorptionOriginofproteinfromsalivaAfterpolishing,reformsrapidlyBacteriasettleonthepellicleassoonasitformsformationofdentalplaque DentalPlaque InthefourthcenturyB.C.Aristotlerelatedsoft,adherefooddepositstotoothdecay,butitwasnotuntiltheadventofthemicroscopeintheseventeenthcenturythat“animalcules(microorganism)wereseeninthesedentaldeposits. Antonvanleeuwenhoek,adraperandsheriff`schamberlaininDelftrecognizedthelimitationofmechanicaloralhygieneinremovingthesedeposits. AntonVanleeuwenhoeksawlargenumbersoflivingcellsinscrapingsfromteeth:IjudgefrommyselfthatallthepeoplelivinginourunitedNetherlandsarenotasmanyasthelivinganimalculesthatIcarryinmyownmouththisveryday. Terminology1847FicinusaslimecoatingdenticulateWilliamsdemonstratedthepresenceofamassofmicroorganisms1895G.V.Blackgelatinousmicrobialplaque DentalplaqueMostfigurativedescription:abacterialaspicwithmillionsoforganismsstandingshouldertoshoulder MoreformaldefinitionbyLőe:plaqueisthesoft,non-mineralized,bacterialdepositwhichformsonteethanddentalprosthesisthatarenotadequatelycleaned MorphologyofdentalplaqueAwhiteoroff-whiteaccumulationVariablethickness Threemaintypiesoforganismscoccoidrod-shapedfilamentous classificationSupragingivalplaqueSubgingivalplaqueDentalcalculus(calcifiedplaque) SupragingivalplaqueSmoothsurfaceplaqueFissureplaque SupragingivalsmoothsurfaceplaqueDividedinto4areas:plaque/toothinterfacecondensedmicrobiallayerbodyoftheplaqueplaquesurface plaque/toothinterfaceInsomelocationsnopelicle Highermagnificationofplaque-enamelborder.Microorganismsthatdivideinhorizontalplanesareindirectcontactwithenamel(130,000). Condensedmicrobiallayeralayerofverydenselypackedcoccoidorganisms,from3~20cellsthick Partofa7-day-oldinterdentalplaquegrownonenamel.Theenamelmatrix(bottom),appearingasafinemeshwork,iscoveredbyathinelectron-denseanddiscontinuouspellicle.Immediatelyabovethisisthecondensedmicrobiallayerwhichiscoveredbyalayerofcoccoidandfilamentousmicro-organismsandprobablyNeisseria.Theintermicrobialspaceiselectron-lucentandrevealscellremnants(16,500). Bodyoftheplaquethisoccupiesbyfarthelargestportionoftheplaque Thinsectionofplaquemadeofdifferentbacterialspecies-predominantlycoccoidal.Denseaggregationofmicroorganismsattheenamelsurface(lowerleft) PlaquesurfacelooselyarrangementGreatvariety:coccoid,rodlike,“corncob” Inthesurfacelayerofplaquesomemicroorganismsco-aggregatewithotherspecies,asvisualizedbythepresenceofso-calledcorncobstructures Magnifiedviewof“corncob”FreesurfaceofplaquecomposedofunidentifiedorganismsFreesurfaceofplaquecomposedofcoccoidgram-positive(heavilystainedcellwalls)andunidentifiedgram-negativemicroorganisms FissureplaqueGram-positivecocciandshortrodspredominateinahomogeneous,matrix,withoccasionalyeastcells Palisadeandbranchingfilamentsareabsentwithinthefissures A:surveyofdentalplaquesituatedwithinadeep,narrowfissureofapremolarB:theupperhalfofthefissureisfilledwithdarkmaterial,thelowerhalfislesdenseC:Highermagnificationrevealsaplaqueconsistingofmostlyghostlikemembraneandcellwallstructures SubgingivalplaqueThematrixissparseOrganisms:filamentousorganisms,bacilli,cocci,spirochetesGramnegativebacteria Thefilamentousnatureofplaqueassociatedwithgingivitis.Noteattachmentofsmallerbacteriatofilaments Calcifiedplaque SupragingivalcalcucuswhitechalkyyellowSubgingivalcalculusgreenishblackDentalcalculusisplaqueinwhichmineralizationhasinvolvedboththeplaquematrixandthemicroorganisms. Formationanddevelopmentofdentalplaques UneventoothsurfaceCariouslesionsill-fillingmarginsofrestorationsIrregularitiesinpositioningoftheteeththelocationfavoringplaqueformation: PellicleformationMicrobialcolonizationProcessofformation PlaqueformationcanbeconsideredasthreephasesInitialcolonizationRapidbacterialgrowthRemodeling BacteriaarethoughttobeunspecificallyassociatedwiththetoothsurfaceundertheinfluenceofVanderwall`sattractiveforcesaswellasrepulsivenegativeelectrostaticforcesInitialmicrobialcolonization Vanderwall’sforcesThereisaweaknessforcesbetweenthemoleculestobeequalto1/10~1/100energeofchemicalbond Dependonthecauseandcharacterofproducingtheforces:OrientationforceInductionforceDispersionforce Orientationforce Inductionforce Dispersionforce Afirmattachmentmaysubsequentlybeachievedbyspecificmechanisms Ligandstheory Recognizedsystem“adhesions”→”receptors” Simplifiedexplanationoftheprincipleofselectiveadherenceofbacteriatoenamel.Successfulattachmentisachievedwhenthesurfacecharacteristicsofabacteriumfitwithacomponentinthepellicle(P) Two-reactionprocessforS.mutansinitialweakattachmentoccursbetweenbacterialcellproteinsandsalivaryglycoproteinsoftheacquiredpellicleandisfollowedbycellularaccumulationmediatedbysucrose-dependentglucansandcellsurfacereceptorligands. Theadherenceofselectedoralbacteriainitiallyinvolvesnonspecific,low-affinity,veryrapidbindingreactionsfollowedbyspecific,high-affinity,slower,butstrongerattachmenttotheacquiredpellicle Microbialsuccession Receptors(oligossacharides)S.Oralishasaglactose-hindingadhesinActiuomycesviscosus→prolinerichproteinStatherins.sangnis→sialicacid Pioneerbacteriacreateanenvironmentwhichiseithermoreattractiveforsecondaryinvadersorincreaseunfavorableconditiontothemselves. Inthiswaytheresidentmicrobialcommunityisgraduallyreplacedbyotherspecies Inmaturedentalplaquetheremaybeasubtlebalance(homeostasis)thattendstoejectinvadingspeciesnotpreviouslypresent. Structuralfeaturesofmicrobialcolonization Initialmicrobialdepositionafteracleanedtoothsurfacehasbeenexposedfor4htotheoralenvironment,surprisinglyfewbacteriaarefound(oneofreports) After4hoursexposuretheenameliscoveredbypelliclewhichisagranulardeposit,primarilylocatedinTomesprocessespits(TP)andinperikymatalgrooves(P)Thefirstbacteriatocolonizethetoothsurfaceareofthecocco-bacillarytype(B).notethatthegranulardepositdoesnotcoverthetoothsurfaceinauniformlayer(PE) Atthisearlystagebacteriaareofthecoccidorcocco-bacillarytypeandalwaysresideinshallowdepressionsonthesurface After8honlyafewsmallergroupsofmicroorganismshavesettledonthesurfaceshelteredbytheperikymata Numerousbacteriaspreadacrossthesurfaceasamonolayer In12-h-oldbacterialdepositsthemicroorganismsspreadinmonolayeralongtheperikymata(P) Insameareasmultiplyingmicroorganismsformmultiplayer,individualorganismsareembeddedinaninter-microbialmatrix. Themonolayerofbacteria(upperpart)isgraduallyreplacedbyamultiplayer(lowerpart)whichisembeddedinanintermicrobialmatrix(X) Within1daythetoothsurfaceisalmostcompletelycoveredbyblanketofmicroorganismsmonolayerareintermittedwithmultilayers. After1daythesurfaceofthemicro-biotaismainlymadeupofcoccoidbacteria,withafewfilaments Duringthecourseofthe2nddaythebacterialdepositsarecolonizedbymultiplefilamentousorganismswithaperpendicularorientationtothesurface Distinctmorphologicalchangesmayberecordedonthesurfaceofthemicrobiotawhencomparingthebacterialdepositsafter24(Fig.5-12)and48h(Fig.5-13).Whereasthe24-h-oldbacterialdepositcomprisesamassofcoccoidbacteriafromwhichafewfilamentsextend,the48-h-oldmicrobiotaisalmostentirelydominatedbyfilamentousorganisms28 Initialcolonizationofrootcementumoccursinprincipleasoutlineforenamelsurface,butprocessmorerapidly Becauseoftheirregularsurfacetotopographyofrootsurfaces,colonizationdoesnottakeplaceaccordingtoaparticularpattern 48-h-oldbacterialdepositsonrootcementumandenamelsurfacesfromthesameindividual.Notethatthemicrobialdepositsarethickerandmoredenselypackedonrootcementum maturedentalplaque Duringtheearlydays,plaquegrowthoccursmainlyasaresultofcelldivision,butcontinuousadsorptionofsinglemicroorganismsfromsalivaalsocontributestotheexpansionofthebacterialdeposit Thecorncobarecomposedofacentralfilamentcoatedwithsphericalorganisms,andappeartohaveadirectinterspeciesrelationshipmachinatedbysurfacefibrils Asthemicrobiotagrowsolder,characteristicstructuralchangesarenoteddeeptothesurface.Themoststrikingchangeistheformationofaninnerlayerofdenselypackedgram-positivepleomorphicbacterianexttothetoothsurface Ultrastructureof2week-olddentalplaquefrom3individualswithdifferentcolonizationpatterns.Notethat,inadditiontodifferencesinthickness,theouterpartsofthedepositsvaryincompositionandstructure. Relativeproportionsofselectedorganismsindevelopingsupragingivalplaqueonthelabialsurfaceofincisors.Plaquesampleswereobtained1,3,5,7,and9daysafterthoroughprophylaxis. Chemicalcompositionofplaqueplaquecontainabout80%water20%solidsprotein40%to50%carbohydratesaccountfor13%to18%lipidsaccountfor10%to14%other DirectsmearsCountof2×1011microorganisms/gIncentrifuge3×1011organisms/g 2/3ofplaquemustconsistofbacteriathatmeans70%theareaiscomposedofmicroorganismsand30%ofintercellularmaterial(matrix) CarbohydratesofplaqueGlucoseisthemaincarbohydratefoundinhydrolyzedextractsofplaquearabinoseribosegalactosefucose Muchofthecarbohydrateexistsintheformofextracellularpolymersglucans(homopolymersofglucose)fructans(homopolymersoffructose)Heteropolysaccharides PlaquemicroorganismsformingextracellularpolysaccharidesGlucansFructansHeteropolysaccharidesStreptococcussanguisActinomycesviscosusActinomycesviscosusStreptococcusmutansStreptococcusmutansLactobacillusbuclneriStreptococcussalivariusStreptococcussalivariuslactobacilluscellobiosusStreptococcusmitiorLactobacilluscaseiLactobacilluscaseiLactobacillusacidophilusNeisseriasp. Cariogenicbacteria Ratsraisedunderbacteria-freeconditionsdidnotdevelopcariesIn1960Keyesperformedaseriesofexperimentsthatestablisheddentalcariesasinfectiousdisease Diagramofcariesformationduetopassageofbacteriafromratdamstotheirpups,eliminationofthediseasebytreatmentofanimalswithantibiotics,andtheoccurrenceofcariesfollowingvarioustypesofinoculations.Theinfectionwasreintroducedbycontactwithinfectedanimals,inoculationwithisolatedstrainsof“caries-inducing”streptococci,andtransferofbacterialplaqueorfeces. DR.ROBERTKOCH Theagentmustbepresentineverycaseofthedisease;Theagentmustbeisolatedfromthehostandgrowninalabdish;Thediseasemustbereproducedwhenapurecultureoftheagentisinoculatedintoahealthysusceptiblehost;ThesameagentmustberecoveredagainfromtheexperimentallyinfectedhostKoch’spostulates SpecificbacteriaandcariesLactobacillithesebacteriawerethoughttoplayanimportantroleincariesetiologywhenitwasfirstfoundthatearlycariousplaquecontainedelevatedlevelsoflactobacillicomparedwithplaquefromnon-carioussurfaces LactobacillCariesfreegroup:100/mlCariesactivegroup:100000/ml Inagroupofcaries-freechildrenthemeannumberoflactobacilliper1mlofsalivawasinthehundreds,whileincariesactivechildrenthemeannumberper1mlwasintherangeof100,000. Theearlyobservationonchangesinlactobacilluslevelsintheoralcavityledmanydentalscientiststoconsiderthesebacteriaasthespecificmicrobialetiologicalfactorinhumancaries Foranumberofreasons,thelactobacillifailedtoqualifyasanexclusiveetiologicalagentinhumancariesformation: Theaffinityoflactobacillifortoothsurfaceislow,<0.01% Highlevelsoflactobacillitendtoexistaftercarieshasdeveloped,cariescanfrequentlybeinitiatedintheabsenceofdetectablelactobacilli. Thelactobacilliaresecondaryinvaders,theymaycontributetotheprogressionofdecayduetotheiracidogenicandaciduricpropertiesConclusion Streptococci Invitrostudieswiththeoralstreptococcihavedemonstratedmanyfeaturesthatsupporttheirroleascariogenicagents RelativelyrapidgenerationToproducelargequantitiesofacidAciduricToutilizeawiderangeoffermentablecarbohydratesToproduceextracellularpolysaccharidesTostoreintracellularcarbohydrateToformplaquematrix Streptococcusmutans Intheearly1920’s,Clarkattemptedtoevaluatetheetiologyofcariesbyanalyzingthemicrobialcontentofplaquefromhumancariouslesions Astreptococcalbacteriumwasconsistentlyisolatedfromthesamplesanditspleomorphicnature(rangefromcoccitorods,dependingonthecultureconditions)causedittobenamedStreptococcusmutans Orlandetc.demonstratedthatmicroorganismswererequiredforimitationofdentalcariesinratsIn1960’sattheNIDRgotaseriesofsuccess KeyesandFitzgeraldshowedthatinrats,cariesisaninfectiousandtransmissibledisease,andthatspecificstreptococcifromcariouslesioninanimalscouldinduceextensivedecayinhamsters. S.mutansandHumancaries S.mutansrepresentslessthan1%theflorainpooledplaquefromcaries-inactiveindividuals S.mutansnormallymakesup5%to10%ofthetotalbacteriapresentinpooledplaquesamplesobtainedfromcaries-activesubjects HighconcentrationsofS.mutansisfoundmainlyatretentivesitessuchascarieslesions,occlusalsurface,pitsandfissures,andapproximalareas AseriesstudiesindicatethatS.mutansissignificantinvolvedinocclusalfissuredecay S.mutansandsucrose OneofthemoreuniquefeaturesofS.mutansistheabilitytoutilizedietarysucrosetoenhancecolonizationoftheoralcavity S.mutanshastheabilitytometabolizethedisaccharidesucrosebyseveralpathways Twoextracellularsucrose-dependentpolysaccharide-formingenzymesareconstitutivelyproducedandexcretedfromthecellbyS.mutans Dextransucraseorglucosyltransferase(GTF)istheenzymeresponsibleforglucanproduction. WhenglucanisformedbyGTF,theproductscontainvaryingproportionsof(16)and(13)linkage The(13)linkagearecriticallyimportantinthatastheirproportionincreasestheglucanbecomeslesssolubleinwater Classificationofmutansstreptococci Othercariogenicbacteria Bacteriacapableofproducingcariouslesionsatdifferentsitesinthedentitionofgerm-freeratssiteBacteriumSmoothocclusalRootSurfacesFissuresSurfacesLactobacillusacidophlilus-+-Lactobacilluscasei-+-Streptococcusmutans+++Streptococcussanguis-+-Streptococcussalivarius++-Streptococcusmitior-+-Streptococcusmilleri++-Streptococcusfaecalis-+-Actinomycesviscosus-+-Actinomycesnaeslundii-++Actinomycesisraelii-++Rothiasp.--+ TheActinomycesspeciesandothergrampositiverodsmaybeinvolvedintheinitiationoflesionsonrootsurfacesofhumanteeth Membersofthegenusveillonellaareobligateanaerobesandarefoundinsignificantnumbersindentalplaqueandsaliva Withinplaquethesebacteriahavethecapacitytoutilizelacticacidandconvertittolessharmfulproducts Theprogressonbioflmsresearch Ourunderstandingofbiofilmshasbeenadvancedoverlastdecadebytheapplicationofnoveltechniques. Theseincludenon-invasiveandnon-destructivemicroscopictechniques(e.g.scanningconfocallasermicroscopy) Thatbiofilmsareusuallylightlystructuredwithchannelstraversingthedepthofbiofilm,creatingprimitivecirculatorysystem. Whatisthesignificanceofbiofilms Geneexpressioncanaltermarkedlywhencellformabiofilm,resultinginmanyorganismshavingaradicallydifferentphenotypefollowingattachmenttoasurface. DNAmicroarrayshaveshowthat73genesand50%ofthedetectableproteomeweredifferentiallyregulatedinbiofilmsofP.aeruginosawhencomparedwithconventionalliquidgrown(planktonic)cell. Cell-cellcommunication Gram-positivebacteriagenerallycommunicateviasmalldiffusiblepeptidesGram-negativebacteriasecreteacylhomoserinelactones(AHLS) TheMICofanorganismgrowingonasurfacecanrangefromtwo-to1000-foldgreaterthanthesamecellsgrownplanktonically Whatisthesignificanceofmicrobialcommunities Thecomponentorganismsarenotmerelypassiveneighborsbutratherthattheyareinvolvedinwiderangeofphysical,metabolicandmolecularinteractions. Thiscommunitylife-styleprovidesenormouspotentialbenefitstotheparticipatingorganisms AbroaderhabitatrangeforgrowthAnincreasedmetabolicdeversityandefficiencyAnenhancedresistanctoenvironmentalstress Horizontalgenetransferisalsomorefeasibleinmulti-speciesbiofilms PlaquestructureConfocallaserscanningmicroscopyhasrevealedthatsupergingivalplaquecanhaveastructuredarchitecture. Polymer-containingchannelsorporeshavebeenobservedthatlinktheplaque/oralenvironmentinterface. Typicalvertical(xz)sectionthroughafour-dayhumanplaquesampletakeninreflected-lightmode.Imagesweretakenat0.6-umintervalsfromthetopofthebiofilmtotheenamelsurfaceunderlyingit.Theimageclearlydemonstratesthebacterialaggregates(grey-white)separatedbyareasoflowreflectance(arrowed)presumedtobechannels.Invertedbiomass(M)andassociatednarrowattachmentpoints(A)canalsobeobserved.Scalebar=25um Thatbacterialvitalityvariesthroughoutthebiofilm,withthemostviablebacteriapresentinthecentralpartofplaqueandliningthevoidsandchannels. Two-colorxysectionofafluorescein-stainedbiofilmshowingreflectedlight(red)andfluorescence(green)atadepthof20umbelowtheplaquesurface. Opticalsections(1umeach)ofbiofilm2,vitalfluorescencevisualization.Firstlayerstartingadjacenttoenamel(bottom,left),13thlayer25umapartfrombottom(top,left). ConsiderableheterogeneityinpHoverrelativelyshortdistancesinmodelmixedcultureoralbiofilms.Suchenvironmentalheterogeneitywillallowfastidiousbacteriatosurviveinplaque,andenablemicroorganismstoco-exist. Thisexplainshoworganismswithapparentlycontradictorymetabolicandgrowthrequirementsareabletopersistatthesamesite. Bacterialcompositionofdentalplaquebiofilms Newtechniques16srRNAamplificationFISHCheckboardDNAhybridizationDNAmicroarray Thatapproximately50%cellsinplaquecannotasyetbeculturedinthelab. Around40%ofamplifiedclonesrepresentnovelphynotypes. Theseculture-independentstudiesarechangingourviewsontheroleofbacteriaindisease. Thatpoorlyclassifiedorganismsthatarecurrentlydifficultorimpossibletogrowinthelabcanpredominateindeeppockets. Biofilmregulationofgeneexperession DuringtheinitialstagesofbiofilmformationbyS.mutans(first2hfollowingattachment),33proteinsweredifferentiallyexpressed(25proteinswereup-regulated,8proteinsdown-regulated) Tocommunicatewithoneanotherinacelldensity-dependantmannerviasmalldiffusiblemolecules. LysedcellsinbiofilmscouldactasdonorsofchromosomalDNA,therebyincreasingtheopportunityforhorizontalgenetransferindentalplaque. Thatoralbacteriadonotexistasindependententitiesbutratherfunctionasaco-ordinated,spetiallyorganizedandmetabolicallyintegratedmicrobialcommunity. Thanks 化学式的计算 1、计算化学式量（相对分子质量）：化学式中各原子的相对原子质量总和。[例题1]：计算下列物质的相对分子质量。N2的相对分子质量=H2SO4的相对分子质量=Cu(OH)2的相对分子质量=14×2=281×2+32+16×4=9864+（16+1）×2=98思考：2H2O的相对分子质量怎样计算？ H2O（1×2）（16×1）:１:８＝1个H2O分子中2个H2O分子中H原子的质量O原子的质量n个H2O分子中活动与探究:2×（1×2）2×（16×1）:１:８＝n×（1×2）n×（16×1）:１:８＝ 水中氢元素的质量氧元素的质量:＝氢原子的相对原子质量×个数:氧原子的相对原子质量×个数H2O（1×2）（16×1）:１:８＝1个H2O分子中2个H2O分子中H原子的质量O原子的质量n个H2O分子中活动与探究:=（1×2）：（16×1）=1：82×（1×2）2×（16×1）:１:８＝n×（1×2）n×（16×1）:１:８＝ 2、计算组成化合物中各元素的质量比[例题2]：计算下列物质中各元素的质量比。H2OCO2N2O3（1×2）：（16×1）=1：812：（16×2）=3：8（14×2）：（16×3）=7：12化合物中元素质量比＝元素的相对原子质量×分子中的原子个数之比 [例题3]：计算下列物质中各元素的质量比。NH4NO3CO(NH2)2(14×2):(1×4):(16×3)=7:1:1212：16:(14×2):(1×4)=3:4:7:1 3、计算物质中某元素的质量分数。例题4H2O中氢元素的质量分数？ 3、计算物质中某元素的质量分数。例题4H2O中氢元素的质量分数？水中氢元素质量分数=氢原子相对原子质量×氢原子个数水的相对分子质量×100﹪某元素的质量分数=该原子相对原子质量×原子个数化合物的相对分子质量×100﹪=1×21×2+16×1×100%≈11.1%解：答：水中氢元素的质量分数为11.1% 1、计算氧化铁（Fe2O3)中铁元素的质量分数2、计算尿素CO(NH2)2中氮元素的质量分数练习1 1、计算氧化铁（Fe2O3)中铁元素的质量分数56x2解：氧化铁中铁元素的质量分数=56x2+16x3X100%=70%答：氧化铁中铁元素的质量分数为70%练习1 解：CO(NH2)2中N元素的质量分数=14X212+16+（14+1×2）X2X100%≈46.7%若测得某种尿素样品中的含氮量为43%，判断该物质是否纯净？2、计算尿素CO(NH2)2中氮元素的质量分数练习1 练习2计算碳酸钙CaCO3中钙元素的质量分数。CaCO3中钙元素的质量分数=10040×1×100%=40%解：答：CaCO3中钙元素的质量分数为40% [练习3]：60克CaCO3中含钙元素多少克？10040×1×100%=60g×40%=24g解：60g×答：60克CaCO3中含钙元素24克。 练习4多少克碳酸钙中含有钙元素8g? 某化合物的化学式为RO2，其中氧元素的质量分数为50%，求R的相对原子质量并确定R为何元素？练习5 知识回顾1、化学式量=2、化合物中元素质量比＝3、某元素的质量分数= 知识回顾1、化学式量=各原子相对原子质量之和2、化合物中元素质量比＝元素的相对原子质量×分子中的原子个数之比3、某元素的质量分数=该原子相对原子质量×原子个数化合物的相对分子质量×100﹪ 已知酒精的化学式为C2H6O，从酒精的化学式中你能获得哪些信息？挑战自我 1．Mg(OH)2相对分子质量的计算式为（）（A）24+16+1×2（B）24×（16+1）×2（C）24×16+1×2（D）24+（16+1）×22．2H2O相对分子质量的计算式为（）（A）2+1×2+16（B）2×1×2×16（C）2×（1×2+16）（D）2×1×2+163．H2SO4的相对分子质量为，在H2SO4中氢、硫、氧三种元素的质量比。氢、硫、氧三种元素的原子个数比。DC981：16：322：1：4快乐尝试'