学习龋病学需要了解的人课件

DentalCariesOuyangYong

AssociateprofessorDepartmentofEndodonticsandOperativeDentistrySunYat-senUniversity岳松龄

王满恩

史俊南

刘正

樊明文

李玉晶王嘉德

周学东

高学军凌均棨刘天佳学习龋病学需要了解的人史俊南刘正樊明文李玉晶周学东凌均棨吴补领高学军IntroductionPhotosofdentalcariesPhotosofdentalcariesPhotosofdentalcaries'Caries'isLatinfor'rot'or'rotten'.Dentalcariesmeansrottenteeth.CariesisthenounwhichnamesthediseaseCariousistheadjective,not'acaries‘,'acariousarea'or'anareaofcaries'.DentalcariescanbedefinedasChronicprogressivedeconstructivediseaseofharddentaltissuesBacterialinfecteddiseasescausedbyspecificbacteriaareversiblemultifactorialprocessoftoothdemineralizationandremineralization.

DentalcariesDentalcaries,abacterialinfection,maybedefineasaposteruptivepathologicalprocessofexternalorigin,involvingthesofteningoftheharddentaltissueandproceedingtocavityformation.Thisisdistinctfromthedissolutionoftheharddentaltissuesofanuneruptedtoothwhichisnotdentalcariesbuttoothresorption.Thecariousprocess

a

pathologicalprocessoflocalizeddestructionofcalcifiedtoothtissuesbyacidsproducedbyorganisms.Etiologicallycariesisconsideredamulti-factorialdisease,whichinvolvesinterplaybetweenthehost(salivaandteeth)microorganisms(streptococcusmutans),andthesubstrate(dietarycarbohydratesucrose),withtheproductionofLacticacid.Dentalplaque(Bio-film)servesasthemediumforcariesdevelopment.Basicpathologicalchangesdemineralizationofinorganic

tissuesoftoothDisintegrationoftheorganictissuesoftoothinvolvesenamel,dentin,cementum

Epidemiologyofdentalcaries

流行病学Prevalencerate（患病率）：

istheproportionofapopulationaffectedbyadiseaseofaconditionatonepointtime.Incidence（发病率）：

isamesurementoftherateatwhichadiseaseprogresses

theincreaseordecreaseinthenumberofnewcasesoccurringinapopulationwithinthesametimeperiodMeasuringcariesactivityDMFindexD

themeannumberofdecayedteethwithuntreatedcariouslesionsM

themeannumberofteethwhichhavebeenextractedandarethereforemissingFthemeannumberoffilledteethDMF(T)

todenotedecayed,missing,andfilledteethDMF(S)

todenotedecayed,missing,andfilledsurfacesinpermanentteethdmf(t)

dmf(s)

similarindicesfortheprimarydentitionFrequencydistributionofdentalcariesaccordingtovarioustoothlocation

permanentdentitionDeciduousdentitiondistributionofdentalcariesaccordingtotoothsurfaceOcclusal>interproximal>buccalCariesisworldwideinitsdistribution

TheprevalenceofdentalcariesincreaseswiththedevelopmentofeconomyHighDMFbefore1970intheindustrializedcountryTodecreaseafter1970intheindustrializedcountryMoreprevalenceinindustrializedthaninthethirdwordcountryCariesexperiencetendstoincreaseinthedevelopingcountryanddeclineinmanywesterncountries.Cariesexperienceishigherinurbanthaninruralcommunitiesindevelopingcountries.Prevalenceofdentalcaries(1995)，specialfor12-18Yagegroupsisincreasedsignificantly（20-40%）Inrecent10years,prevalenceofdentalcariesinprimarydentitionisincreasedsignificantlythanthepermanentWhyhascariesprevalencedecreasedinmodernpopulation?TheispossiblyattributabletoThefluoridationofdrinkingwater,useoffluoridetoothpastesandimprovedoralhealthAchangingpatternofsugarconsumptionAdecreaseinvirulence(毒力)oftheorgansims

Aetiologyofdentalcaries

龋病的病因学原发性釉护膜(primaryenamelcuticle)残余釉上皮（reducedenamelepithelium)获得性膜（acquiredpellicle）食物碎片（fooddebris,materialalba）牙菌斑（dentalplaque）牙结石（calculus,tartar）Theorganicdepositsontheenamelsurface

fourfactorsisessentialfortheinitiationofdentalcaries,namely:Micro-organismmutansstreptococciLactobacilliActinomycesSubstrateRefinedcarbohydrates(精制碳水化合物)suchassucrose蔗糖

provideasuitablesubstrateonwhichthecariogenicmicro-organismsacttoproducetheacidsthatleadtodissolutionoftheharddentaltissuesCariesexperienceisinfluencedbythequantity,qualityandespeciallyfrequencyofconsumptionoftherefinedcarbohydrateSusceptibleteeth易感牙Theingestionoffluoridesduringtoothmineralizationleadstotheformationoffluor-apatiteinenamel.Itspresenceinenamelmakesthetoothlesssusceptibletodentalcariesbecauseitislesssolubleinacidthanthehydroxyapatite(羟磷灰石)whichisnormallypresentintheharddentaltissuesTimeAllthefactorsshouldbepresentforsufficientlylongtimeforthecariesprocesstobeinitiated.Definition:Dentalplaque（牙菌斑）ClassificationofDentalplaquesupragingivalplaque

-----dentalcariessubgingivalplaque-----periodontaldiseasesSTRUCTUREOFDENTALPLAQUEPlaqueonsmoothsurface

Plaque-dentalsurfaceMiddlelayer----condensedmicrobiallayerbodyofplaqueThesurfacelayerofplaquePlaqueinpitandfissureCompositionofDentalplaquebacteriawhichform50-70%ofdentalplaque

asmallnumberofepithelialcellsLeukocytesMacrophagesglycoproteinswhich,togetherwithextracellularpolysaccharides,formtheplaquematrixmucopolysaccharides

(粘多糖)suchasglucansandfructans(右旋糖)

Inorganiccomponentscalciumphosphorusfluorides.MECHANISMSOFPLAQUEFORMATIONTheattachment,growth,removalandreattachmentofbacteriatothetoothsurfaceisacontinuousanddynamicprocess.SeveraldistinctprocessescanberecognizedAbsorptionofsalivaryproteinsandglycoproteins,togetherwithsomebacterialmolecules,tothetoothsurfacetoformaconditioningfilm(theacquiredpellicle).——获得性膜的形成non-specificinteractionofmicrobialcellsurfaceswiththeacquiredpellicleviavanderWallsattractiveforces.Irreversibleadhesioncanoccurifspecificinter-molecularinteractionstakeplacebetweenadhesionsonthecellsurfaceandreceptorsintheacquiredpellicle.Secondaryorlate-colonizersattachtoprimarycolonizers(coaggregation共集),alsobyspecificinter-molecularinteractions.FORMATIONANDDEVELOPMENTOFDENTALPLAQUEFormationofacquiredpellicleandprimaryaggregationBacteriagrowthanddevelopmentThematureofdentalplaqueDevelopmentPellicleformation

Microorganismsdonotattachthermselvesdirectlytothemineralizedtoothsurfaceandtheteetharealwayscoveredbyanacellularproteinaceousfilm,thepellicleFormsonthe“naked”toothsurfacewithinminutestohoursSalivaryglycoproternsCarbohydratesLipidalesserextentcomponentsfromthegingivalcrevicularfluid(龈沟液)MajorconstituentsofPellicleBecauseofitsselectivenaturerestricttransportationofironsinandoutofthedentalhardtissue.ItmayplayanimportantmodifyingroleincariesProvidefurtherprotectionagainstdemineralizationoftheenamelModifythenumberofpotentialadsorptionsitesfordifferentbacterialspeciesAsthesubstrateforthemicroorganisms

FunctionofPelliclemicrobialcolonizationInitialmicrobialcolonizationstreptococcusmutans(变形链球菌)

accountingfor56%ofthetotalinitialmicrofloraActinomyces

spp(放线菌)

aminorproportion

gram-negativebacteria(G-)MicrobialsuccessionTheinitialestablishmentofastreptococcalfloraappearstobeanecessaryantecedentforthesubsequentproliferationofotherorganismsThemoststrikingchangedisshiftfromstreptococcus-dominatedplaquetoplaquedominatedbyActinomyces.MICROBIALAETIOLOGYOFCARIESanimalstudies

micro-organismsareinvolvedintheaetiologyofdentalcaries

cariogenicmicroorganisms

Streptococcusmutanslactobacillus

ActinomycesCariogenicproperties

(致龋菌的特性)theyareabletoproduceacidrapidlyfromfermentablecarbohydrates(acidogenic).Theythriveunderacidconditions(aciduric)

abletoadheretothetoothsurfacebecauseoftheirability

tosynthesizestickyextracelluarpolysaccharidesfromdietarysugarsAdvancedlesionsoftenhaveahighproportionoflactobacillidentinallesionshaveadiversemicroflorawithmanyGrampositiveGramnegativebacteria.RootsurfacecarieswasoriginallyassociatedwithActinomyces

spp.butrecentstudiessuggestasimilaraetiologytoenamelcariesRampantcariescanoccurinxerostomicpatientsandininfantsfedwithhighlevelsofsugarinpacifiers(nursingbottlecaries).Theplaquecontainshighlevelsofmutansstreptococciandlactobacilli.Micro-organismandcariesHypothesesandtheoryrelatingtoAetiologyofdentalcariesChemico-parasitictheory

(化学细菌学说)Thispostulatesthatoralbacteriaactonsugartoproduceacidwhichdemineralizestheinorganiccomponentofenamel,resultinginthedevelopmentofacariouslesion.Proteolytictheory(蛋白溶解学说)Itisthoughtthattheorganiccomponentofenamelisfirstbrokendownbyproteolyticenzymes,openinguppath-waysforbacteriatoattacktheenamelbyotherprocessessuchasbyacidorbychelation.Chelationtheory(螯合学说)ThispostulatesthatenamelisdemineralizedbychelatingagentsatneutralpH.Proteinbreakdownproductsaswellaslacticacidaresomechelatingagentsknowntoexistinnature.Auto-immunitytheoryInthistheory,itissuggestedthat'forbiddenclones'oflymphocytesattacktargetcells(odontoblasts)renderingthetoothvulnerabletocariesattack.

FourfoctorstheoriesmicroorganismsHost&toothsubstratetimecariesThefourcirclediagrammaticallyrepresenttheparametersinvolvedinthecariousprocess.Allfourfactorsmustbeactingconcurrently(overlappingofthecircles)forcariestooccur.TheroleofdietarycarbohydrateNutrition------systemicdietaryeffectsDiet------localdietaryeffectsCariesprevalenceislowinpopulationsadheringtoaprimitivewayoflivingandadietoflocalproductswithlittlesugarAdrasticincreaseincariesisinvariablyseenwhenthesepopulation“improve”theirstandardoflivingandadoptamodern“civilized”dietwithhighsugarcontentAstrongcorrelationbetweencariesdevelopmentandsugarconsumption

epidemiologicalstudiesSucrose(蔗糖)------calledthearch-criminalindentalcaries

Monosaccharides,disaccharidesandofthepolysaccharidestarchcanbefermentedtoacidbytheplaquebacteriaSorbitol（山梨糖）xylitol(木糖醇)-----sugarsubstitutesusedinsugar-freechewing-gumsDietaryhabitsandcariesprevalenceHost&tooth(susceptibleteeth)Itwasaclinicalexperiencethatnotallindividualswithpoororalhygieneandfrequentsugarcon