学习龋病学需要了解的人.ppt

DentalCaries,OuyangYongAssociateprofessorDepartmentofEndodonticsandOperativeDentistrySunYat-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,Introduction,Photosofdentalcaries,Photosofdentalcaries,Photosofdentalcaries,CariesisLatinforrotorrotten.Dentalcariesmeansrottenteeth.CariesisthenounwhichnamesthediseaseCariousistheadjective,notacaries,acariousareaoranareaofcaries.,Dentalcariescanbedefinedas,ChronicprogressivedeconstructivediseaseofharddentaltissuesBacterialinfecteddiseasescausedbyspecificbacteriaareversiblemultifactorialprocessoftoothdemineralizationandremineralization.,Dentalcaries,Dentalcaries,abacterialinfection,maybedefineasaposteruptivepathologicalprocessofexternalorigin,involvingthesofteningoftheharddentaltissueandproceedingtocavityformation.Thisisdistinctfromthedissolutionoftheharddentaltissuesofanuneruptedtoothwhichisnotdentalcariesbuttoothresorption.,Thecariousprocess,apathologicalprocessoflocalizeddestructionofcalcifiedtoothtissuesbyacidsproducedbyorganisms.Etiologicallycariesisconsideredamulti-factorialdisease,whichinvolvesinterplaybetweenthehost(salivaandteeth)microorganisms(streptococcusmutans),andthesubstrate(dietarycarbohydratesucrose),withtheproductionofLacticacid.Dentalplaque(Bio-film)servesasthemediumforcariesdevelopment.,Basicpathologicalchanges,demineralizationofinorganictissuesoftoothDisintegrationoftheorganictissuesoftoothinvolvesenamel,dentin,cementum,Epidemiologyofdentalcaries流行病学,Prevalencerate（患病率）：istheproportionofapopulationaffectedbyadiseaseofaconditionatonepointtime.Incidence（发病率）：isamesurementoftherateatwhichadiseaseprogressestheincreaseordecreaseinthenumberofnewcasesoccurringinapopulationwithinthesametimeperiod,Measuringcariesactivity,DMFindex,DthemeannumberofdecayedteethwithuntreatedcariouslesionsMthemeannumberofteethwhichhavebeenextractedandarethereforemissingFthemeannumberoffilledteethDMF(T)todenotedecayed,missing,andfilledteethDMF(S)todenotedecayed,missing,andfilledsurfacesinpermanentteethdmf(t)dmf(s)similarindicesfortheprimarydentition,Frequencydistributionofdentalcariesaccordingtovarioustoothlocation,permanentdentition,Deciduousdentition,distributionofdentalcariesaccordingtotoothsurface,Occlusalinterproximalbuccal,Cariesisworldwideinitsdistribution,TheprevalenceofdentalcariesincreaseswiththedevelopmentofeconomyHighDMFbefore1970intheindustrializedcountryTodecreaseafter1970intheindustrializedcountryMoreprevalenceinindustrializedthaninthethirdwordcountryCariesexperiencetendstoincreaseinthedevelopingcountryanddeclineinmanywesterncountries.Cariesexperienceishigherinurbanthaninruralcommunitiesindevelopingcountries.,Prevalenceofdentalcaries(1995)，specialfor12-18Yagegroupsisincreasedsignificantly（20-40%）Inrecent10years,prevalenceofdentalcariesinprimarydentitionisincreasedsignificantlythanthepermanent,Whyhascariesprevalencedecreasedinmodernpopulation?,TheispossiblyattributabletoThefluoridationofdrinkingwater,useoffluoridetoothpastesandimprovedoralhealthAchangingpatternofsugarconsumptionAdecreaseinvirulence(毒力)oftheorgansims,Aetiologyofdentalcaries龋病的病因学,Theorganicdepositsontheenamelsurface,fourfactorsisessentialfortheinitiationofdentalcaries,namely:,Micro-organismmutansstreptococciLactobacilliActinomyces,SubstrateRefinedcarbohydrates(精制碳水化合物)suchassucrose蔗糖provideasuitablesubstrateonwhichthecariogenicmicro-organismsacttoproducetheacidsthatleadtodissolutionoftheharddentaltissuesCariesexperienceisinfluencedbythequantity,qualityandespeciallyfrequencyofconsumptionoftherefinedcarbohydrate,Susceptibleteeth易感牙Theingestionoffluoridesduringtoothmineralizationleadstotheformationoffluor-apatiteinenamel.Itspresenceinenamelmakesthetoothlesssusceptibletodentalcariesbecauseitislesssolubleinacidthanthehydroxyapatite(羟磷灰石)whichisnormallypresentintheharddentaltissues,TimeAllthefactorsshouldbepresentforsufficientlylongtimeforthecariesprocesstobeinitiated.,Definition:,Dentalplaque（牙菌斑）,ClassificationofDentalplaque,supragingivalplaque-dentalcariessubgingivalplaque-periodontaldiseases,STRUCTUREOFDENTALPLAQUE,PlaqueonsmoothsurfacePlaque-dentalsurfaceMiddlelayer-condensedmicrobiallayerbodyofplaqueThesurfacelayerofplaquePlaqueinpitandfissure,CompositionofDentalplaque,bacteriawhichform50-70%ofdentalplaqueasmallnumberofepithelialcellsLeukocytesMacrophagesglycoproteinswhich,togetherwithextracellularpolysaccharides,formtheplaquematrixmucopolysaccharides(粘多糖)suchasglucansandfructans(右旋糖)Inorganiccomponentscalciumphosphorusfluorides.,MECHANISMSOFPLAQUEFORMATION,Theattachment,growth,removalandreattachmentofbacteriatothetoothsurfaceisacontinuousanddynamicprocess.,Severaldistinctprocessescanberecognized,Absorptionofsalivaryproteinsandglycoproteins,togetherwithsomebacterialmolecules,tothetoothsurfacetoformaconditioningfilm(theacquiredpellicle).获得性膜的形成non-specificinteractionofmicrobialcellsurfaceswiththeacquiredpellicleviavanderWallsattractiveforces.,Irreversibleadhesioncanoccurifspecificinter-molecularinteractionstakeplacebetweenadhesionsonthecellsurfaceandreceptorsintheacquiredpellicle.,Secondaryorlate-colonizersattachtoprimarycolonizers(coaggregation共集),alsobyspecificinter-molecularinteractions.,FORMATIONANDDEVELOPMENTOFDENTALPLAQUE,FormationofacquiredpellicleandprimaryaggregationBacteriagrowthanddevelopmentThematureofdentalplaque,Development,PellicleformationMicroorganismsdonotattachthermselvesdirectlytothemineralizedtoothsurfaceandtheteetharealwayscoveredbyanacellularproteinaceousfilm,thepellicleFormsonthe“naked”toothsurfacewithinminutestohours,SalivaryglycoproternsCarbohydratesLipidalesserextentcomponentsfromthegingivalcrevicularfluid(龈沟液),MajorconstituentsofPellicle,Becauseofitsselectivenaturerestricttransportationofironsinandoutofthedentalhardtissue.ItmayplayanimportantmodifyingroleincariesProvidefurtherprotectionagainstdemineralizationoftheenamelModifythenumberofpotentialadsorptionsitesfordifferentbacterialspeciesAsthesubstrateforthemicroorganisms,FunctionofPellicle,microbialcolonization,Initialmicrobialcolonizationstreptococcusmutans(变形链球菌)accountingfor56%ofthetotalinitialmicrofloraActinomycesspp(放线菌)aminorproportiongram-negativebacteria(G-),Microbialsuccession,TheinitialestablishmentofastreptococcalfloraappearstobeanecessaryantecedentforthesubsequentproliferationofotherorganismsThemoststrikingchangedisshiftfromstreptococcus-dominatedplaquetoplaquedominatedbyActinomyces.,MICROBIALAETIOLOGYOFCARIES,animalstudiesmicro-organismsareinvolvedintheaetiologyofdentalcaries,cariogenicmicroorganisms,StreptococcusmutanslactobacillusActinomyces,Cariogenicproperties(致龋菌的特性),theyareabletoproduceacidrapidlyfromfermentablecarbohydrates(acidogenic).Theythriveunderacidconditions(aciduric)abletoadheretothetoothsurfacebecauseoftheirabilitytosynthesizestickyextracelluarpolysaccharidesfromdietarysugars,AdvancedlesionsoftenhaveahighproportionoflactobacillidentinallesionshaveadiversemicroflorawithmanyGrampositiveGramnegativebacteria.RootsurfacecarieswasoriginallyassociatedwithActinomycesspp.butrecentstudiessuggestasimilaraetiologytoenamelcariesRampantcariescanoccurinxerostomicpatientsandininfantsfedwithhighlevelsofsugarinpacifiers(nursingbottlecaries).Theplaquecontainshighlevelsofmutansstreptococciandlactobacilli.,Micro-organismandcaries,HypothesesandtheoryrelatingtoAetiologyofdentalcaries,Chemico-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-immunitytheory,Inthistheory,itissuggestedthatforbiddenclonesoflymphocytesattacktargetcells(odontoblasts)renderingthetoothvulnerabletocariesattack.,Fourfoctorstheories,caries,Thefourcirclediagrammaticallyrepresenttheparametersinvolvedinthecariousprocess.Allfourfactorsmustbeactingconcurrently(overlappingofthecircles)forcariestooccur.,Theroleofdietarycarbohydrate,Nutrition-systemicdietaryeffectsDiet-localdietaryeffects,CariesprevalenceislowinpopulationsadheringtoaprimitivewayoflivingandadietoflocalproductswithlittlesugarAdrasticincreaseincariesisinvariablyseenwhenthesepopulation“improve”theirstandardoflivingandadoptamodern“civilized”dietwithhighsugarcontentAstrongcorrelationbetweencariesdevelopmentandsugarconsumption,epidemiologicalstudies,Sucrose(蔗糖)-calledthearch-criminalindentalcariesMonosaccharides,disaccharidesandofthepolysaccharidestarchcanbefermentedtoacidbytheplaquebacteriaSorbitol（山梨糖）xylitol(木糖醇)-sugarsubstitutesusedinsugar-freechewing-gumsDietaryhabitsandcariesprevalence,Host&tooth(susceptibleteeth),ItwasaclinicalexperiencethatnotallindividualswithpoororalhygieneandfrequentsugarconsumptiondevelopcariesInthelaboratory,extractedteethexposedtothesameacidicbu