PAGEPAGE3UnitSeventeenNote:PleasepayattentiontotheunderlinedwordsorphrasesNote:Pleasepayattentiontotheunderlinedwordsorphrasesinadditiontothewordsinblue.ORALDISEASES:PREVENTIONISBETTERTHANCUREOraldiseasessuchascariesandperiodontaldisease(infectionsofthegumsandofthetoothsupporttissues)areamongthemostwidespreaddiseasesintheworld.Theyaffectallpopulationstovaryingdegrees.Dentalcariesintheworld:asituationofcontrastTheindexformeasuringtheextenttowhichapopulationisaffectedbycariesisthemeanDMFT,whichinagroupofindividualscountstheaveragenumberofteeththatareDecayed,Missing(onaccountofcaries)andFilled.Itisasimple,rapidanduniversallyapplicablemeasurementthathasbeenwidelyusedforseveraldecades.Wehavedrawnupascaleforseverityofinvolvementatvariouskeyages:12,35-44,65andover.Atage12the5levelscalevariesfrom0.0to6.6ormore:aDMFTbetween0.0and1.1isconsideredverylow,afigureof6.6ormoreisveryhigh,whileamoderateDMFTisbetween2.7and4.4decayed.AnycountryundertakingananalysisofitsoralhealthsituationcancomparetheresultswithWHO'sworldwideobjective:bytheyear2000nomorethanthreedecayed,missingandfilledteethatage12.Byrepeatingtheanalysisatregularintervals(WHOrecommendsanevaluationeveryfiveyears)itispossibletomonitorthetrendincariesprevalence,toestimatetheneedsforcareandpreventionandtoadjustpersonneltrainingandservicesaccordingly.ItshouldbepointedoutthatthesimplifiedoralhealthsurveymethoddevelopedbyWHOisreliable,veryinexpensive,canbeusedanywhereandprovidescomparabledatabothintherichestcountriesandinthepoorest.WHO'sOralHealthUnitprovidestechnicalsupportforepidemiologicalsurveysandprocessescountrydatafreeofchargeonrequest.TheinformationcollectedisstoredintheGlobalOralDataBank(GODB)systeminthecatalogueofUnitedNationsdatabanks,wherebyitispossibletofollowtheworldwidetrend.Everyyearsince1969,WHOhascompiledaworldmapofcariesatage12.In1969theoverallpictureshowedsharpcontrasts:theDMFTwasveryhigh,highoratleastmoderate(between2.7and4.4)intheindustrializedcountries,whereasitwasgenerallyverylow,lowandoccasionallymoderateinthedevelopingcountries.Overthenexttwodecadestherewasadownwardmovementandsometimesaspectacularfallintheprevalenceofcariesinvirtuallyalltheindustrializedcountries.Inthedevelopingcountriesthegeneraltrendisforcariesprevalencetoincreaseexceptwherepreventionprogrammeshavebeensetup.Everyyearsince1980theWHOOralHealthUnithascalculatedthemeanglobalDMFTatage12,weightedforpopulation.Theresultinggraphsdisplaythetrendsindentalcariesintheindustrializedcountries,inthedevelopingcountriesandformankindasawhole.Thetrendinthemeansince1980justifiesmeasuredoptimismforthenext10years,althoughthesituationisstilldelicateinasmuchasasmallincreaseinveryhighlypopulatedcountriesisallthatisneededtotakethemeanabove3.****Whatistheexplanationforthespectaculardropincariesprevalenceinsomecountries?Howcanitbepreventedfromrisingagain?Howcantheworseningofthesituationinothercountriesbehalted?Thereplytothesethreequestionsisoneandthesame:prevention,morepreventionandstillmoreprevention.Intheindustrializedcountriesthepromotionoforalhygiene,thewidespreaduseoffluoridetoothpaste,theintroductionoffluorideintodrinkingwaterorsaltinsomecountries,adviceonnutrition(nosweetsbetweenmealsandetc.)arethefactorsbehindanunprecedentedpublichealthsuccessstory!Wherevercommunitypreventionprogrammesaresetup,cariesstopadvancing.Forexample,thishashappenedinBulgaria,FrenchPolynesiaandThailand.Apartfromthefluoridationofwater,saltandmilk,whichrequiresmoreadvancedtechnologyandsupervisedcentraladministration,allthemethodsoforalhygienemakeuseofsimpletechniques,costlittleandareperfectlysuitedtoimplementationatprimaryhealthcarelevel.Asaresultoftheprogressmadeinthelast25years,thedevelopingcountriesnowhavetheknowledgeandmeansofpreventionthatwillenablethemtoavoidtheproblemstheindustrializedcountrieshavehadtoface,andindeedstillarefacingataveryhighprice!Inmostindustrializedcountriestheoralhealthservicesstillabsorbbetween5%and11%ofthenationalhealthbudget.Thereisnoreasonatalltocontinuedevotingsubstantialresourcestotreatingaconditionthatcanbepreventedbysimple,variedandinexpensivemeasures.Butthereneedstobethepoliticalwilltogiveprioritytoprevention.****Whataboutthe"periodontaldisease"?Towardstheendofthe1960smostdentalepidemiologistssharedtheviewthatperiodontaldiseases,unlikecaries,weremorecommoninthedevelopingcountriesthanintheindustrializedcountries.However,theavailabledatawereveryfragmentaryanddifficultorimpossibletocomparesincetherewerenofewerthanfivedifferentindicesincommonuse.Thisplethoraofmethodswascompoundedbythedifficultyofcollectingdatafromadults;aproblemthatislessseriousinthecaseofcaries,wherethekeyageis12years.Withthedefinitionofaperiodontalindex,whichveryquicklyachievedwideinternationalacceptance,theepidemiologyofperiodontaldiseaseshasmadegreatstrides.TheCPITN(CommunityPeriodontalIndexofTreatmentNeeds)wasproposedbyaWHOscientificgroupandrecommendedintheearly1980sbyajointworkinggroupfromWHOandtheFDI(InternationalDentalFederation).Thisindexrecordstheperiodontaldiseasesintermsoffourclinicalsigns:l.Bleedingfromthegum2.Presenceofcalculus3.Presenceofshallowperiodontalpockets4.PresenceofdeepperiodontalpocketsA"periodontalpocket"isconsideredtobepresentwhen'thegum,undertheeffectofinflammationand/orinfection,retracts,formsapocketandnolongeradherestothetooth.Theligamentsbecomeimpairedandthetoothbecomesincreasinglyloose.Tomeasureperiodontalstatus,themouthisdividedintosixpartsorsextants.Aspeciallydesignedprobeisusedtotestthecondition(l,2,3or4)ofthegumaroundthetoothselectedastheindextoothforeachsextant.Ifseveralclinicalsignsarepresentsimultaneously,themostsevereisselected.WHOhascompileddataonoverIOOsurveyscarriedoutintheagegroup35-44years.Thesedatashouldbetreatedwithcaution,sinceveryfewofthemprovideanationalestimate.Neverthelesstheyareofgreatinterestbecausetheyconsistentlyshowasimilarpatternoffrequencyandseverityofinvolvement,whichchallengessomegenerallyacceptedideasaboutthedistributionandtheetiologicalprocessofperiodontaldisease.Thedatashowthatthepercentageofpeoplewhohavedeeppocketsandthemeannumberofsextantsperpersonalsodisplayingdeeppocketsarelowtoverylow.Thismeansthatthesevereformsofperiodontaldisease,thoserequiringcomplicatedsurgeryarefarfromcommon.Moreover,thereseemstobenodifferenceinfrequencybetweenindustrializedcountriesanddevelopingcountriesforthesevereformsofperiodontaldisease.Ontheotherhand,theinitialforms(bleedingandcalculus)aremuchmoreprevalentinthedevelopingcountries.Inthelightofthesedataitmaybestatedthatgeneralizedperiodontaldestructionisrarein40-year-oldadults.Somepeopleshowsomesignsofsuchdestruction,butonlyalimitedpartoftheirdentitionisaffected.Itseemsthattheinitialforms(bleedingandcalculus)donotnecessarilyleadontotheadvancedstagesofthedisease,exceptincertainminoritygroups.Howcanthesediseasesbeprevented?Afterafewdaysofcarefulcleaningoftheteeth,thebleedingstopsinthevastmajorityofcasesandtheinflammation,thecauseofmuchdiscomfort,alsoregresses.Therearevariouspossiblepreventionpolicies:hygieneforthemostcommonandleastseriousforms;developmentofproductsthatactagainstthedestructivetypesofperiodontitis.Awholefieldofresearchtoprotecttheriskgroupsisopeningup.VOCABULARYl.gum,gingiva牙齦2.calculus,tartar牙結石3.Fooddebris食物殘渣4.Dentalplaque牙菌斑5.index,indices指數，索引6.meanDMFT齲(牙)均7.D-Decayed齲8.M-Missing(onaccountofCaries)失9.F-Filled補10.Keyages(indexagegroups)指數年齡組11.oralhealthsituation口腔健康狀況12.regularintervals定期，間隔一定時間13.monitor監測，監督14.cariesprevalence患齲15.simplified簡化的16.reliable可靠的17.epidemiologicalsurvey流行病學調查18.preventiveprogromme預防項目(計劃)19.onrequest根據要求20.databank資料庫(數據瘁)21.compile(d)編制22.Sharpcontrast(s)鮮明對比23.downward向下的，下降的24.upward向上的，上升的25.spectacularfall引人注目的下降26.virtually事實上，實際上：27.weightedforpopulation加權人口28.Justify,justifies證明(認為)……有道理，為·…．·提供依據29.optimism樂觀(主義)30.graph座標圖，曲線圖31.worsening(使)惡化、變壞32.halt(ed)停止、止步，休息33.unprecedented空前的，無先例的34.supervised在監督指導下的35.fluoridation氟化36.administration管理37.oralhygiene口腔(清洗)衛生38.primaryhealthcare初級衛生保健39.healthbudget衛生預算40.devote獻(身)，貢獻，專心致力于41.substances實質的，有價值，有實力的42.priority重點，優先43.inexpensivemeasures廉價措施44.share(d)分享，分擔45.periodontaldiseases牙周疾病46.fragmentary片斷的，殘缺不全的47.plethora過多(剩)48.periodontalindex牙周指數49.internationalacceptance國際承認(接受)50.strides(s)邁進，進步51.CPITN(CommunityPeriodontalindexofTreatmentNeeds)社區牙周治療需要指數52.FDI(InternationalDentalFederation)國際牙科聯盟53.bleedinggum牙齦出血54.shallowperiodontalpockets淺牙周袋55.deepperiodontalpockets深牙周袋56.retract(s)退縮，萎縮57.adhere(s)附著，吸附58.ligament(s)韌帶59.impaired受損傷的60.loose(牙)松動61.sextant(s)(牙周)區段62.speciallydesignedprobe專門設計的探針63.indextooth指數牙64.simultaneously同時，—齊65.caution小心、慎重66.similarpat