DentalCariesOuyangYong

AssociateprofessorDepartmentofEndodonticsandOperativeDentistrySunYat-senUniversity岳松齡

王滿恩

史俊南

劉正

樊明文

李玉晶王嘉德

周學(xué)東

高學(xué)軍凌均棨劉天佳學(xué)習(xí)齲病學(xué)需要了解的人史俊南劉正樊明文李玉晶周學(xué)東凌均棨吳補(bǔ)領(lǐng)高學(xué)軍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

流行病學(xué)Prevalencerate（患病率）：

istheproportionofapopulationaffectedbyadiseaseofaconditionatonepointtime.Incidence（發(fā)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

齲病的病因?qū)W原發(fā)性釉護(hù)膜(primaryenamelcuticle)殘余釉上皮（reducedenamelepithelium)獲得性膜（acquiredpellicle）食物碎片（fooddebris,materialalba）牙菌斑（dentalplaque）牙結(jié)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(羥磷灰石)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).——獲得性膜的形成non-specificinteractionofmicrobialcellsurfaceswiththeacquiredpellicleviavanderWallsattractiveforces.Irreversibleadhesioncanoccurifspecificinter-molecularinteractionstakeplacebetweenadhesionsonthecellsurfaceandreceptorsintheacquiredpellicle.Secondaryorlate-colonizersattachtoprimarycolonizers(coaggregation共集),alsobyspecificinter-molecularinteractions.FORMATIONANDDEVELOPMENTOFDENTALPLAQUEFormationofacquiredpellicleandprimaryaggregationBacteriagrowthanddevelopmentThematureofdentalplaqueDevelopmentPellicleformation

Microorganismsdonotattachthermselvesdirectlytothemineralizedtoothsurfaceandtheteetharealwayscoveredbyanacellularproteinaceousfilm,thepellicleFormsonthe“naked”toothsurfacewithinminutestohoursSalivaryglycoproternsCarbohydratesLipidalesserextentcomponentsfromthegingivalcrevicularfluid(齦溝液)MajorconstituentsofPellicleBecauseofitsselectivenaturerestricttransportationofironsinandoutofthedentalhardtissue.ItmayplayanimportantmodifyingroleincariesProvidefurtherprotectionagainstdemineralizationoftheenamelModifythenumberofpotentialadsorptionsitesfordifferentbacterialspeciesAsthesubstrateforthemicroorganisms

FunctionofPelliclemicrobialcolonizationInitialmicrobialcolonizationstreptococcusmutans(變形鏈球菌)

accountingfor56%ofthetotalinitialmicrofloraActinomyces

spp(放線菌)

aminorproportion

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

micro-organismsareinvolvedintheaetiologyofdentalcaries

cariogenicmicroorganisms

Streptococcusmutanslactobacillus

ActinomycesCariogenicproperties

(致齲菌的特性)theyareabletoproduceacidrapidlyfromfermentablecarbohydrates(acidogenic).Theythriveunderacidconditions(aciduric)

abletoadheretothetoothsurfacebecauseoftheirability

tosynthesizestickyextracelluarpolysaccharidesfromdietarysugarsAdvancedlesionsoftenhaveahighproportionoflactobacillidentinallesionshaveadiversemicroflorawithmanyGrampositiveGramnegativebacteria.RootsurfacecarieswasoriginallyassociatedwithActinomyces

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

(化學(xué)細(xì)菌學(xué)說)Thispostulatesthatoralbacteriaactonsugartoproduceacidwhichdemineralizestheinorganiccomponentofenamel,resultinginthedevelopmentofacariouslesion.Proteolytictheory(蛋白溶解學(xué)說)Itisthoughtthattheorganiccomponentofenamelisfirstbrokendownbyproteolyticenzymes,openinguppath-waysforbacteriatoattacktheenamelbyotherprocessessuchasbyacidorbychelation.Chelationtheory(螯合學(xué)說)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