UnitNineteenChernobyl“fall–out”onoralhealthP.A.LeousPoororalhygiene,highprevalenceofperiodontaldisease,andlackofdentalservicearecurrentfeatureoforalhealthamongpeoplelivinginareasofBelaruscontaminatedbytheChernobylnuclearaccident.HerstateoforalhealthwastheleastoftheworriesofthepopulationwhofoundthemselvesinaradioactivezoneaftertheChernobylnuclearpowerstationdisasterin1986.Infact,thefirstteamsofdentistsfromtheMinskMedicalInstitutewhoarrivedatstrictlycontrolledareasofBelarusseveraldaysaftertheaccidenthadnoevidenceofanyspecificoralhealthproblemsamongthepopulation.Furthermore,throughlackofinformation,thedentalscientistshadlittleinterestintheafter-effectsonoralhealth,althoughsomestudiesontheeffectoflowradiationonoralanddentalstructureswereconductedunderlaboratoryconditionsatthePaedodonticsandOralSurgeryDepartments.Publishedinlocaljournals,thesestudiesshoweddifferentkindsofpathologicaleffecttothejawbonesandsoftoraltissues.SincethentherehasbeengrowingconcernaboutthesharpincreaseintheincidenceofthyroudcancerobservedamongchildrenincontaminatedareasofBelarus.Between1986and1991,131caseswerediagnosedcomparedwithonlysevencasesoverthesameperiodoftimebeforetheaccident.Morethan50%ofthesecancerswerefoundinGomelOblast.In1992,67caseswerereported.Aconsiderablegrowthinthyrouddisorderssuchasautoimmunethyroiditishasalsobeenreportedamongchildrenincontaminatedareas.Systematiccontinuousstudiesoftheoralhealthstatusinaffectedareaswererevivedin1990-91.Theirmainpurposewastoassessoralhealthindifferentagegroupsofthepopulationlivinginstrictlycontrolledzones.Anoralhealthproject,whichstartedlatein1992aspartoftheInternationalProgrammeontheHealtheffectsoftheChemobylAccident,aimstoimprovediagnosticandcurativeservicesinoralhealthincontaminatedareasofBelarus.Samplesoftoothenamelcollectedwillbeusedforindividualdosimetrybyelectronspinresonancespectrometry.WHO'sstandardoralhealthsurveymethodswereusedfororalexaminationswhichhighlightedseveralriskfactorsorcofactorsoforaldisease.Fordentalcaries.salivaryfunction,oralhygiene,fluorideintakeandotherdietarycomponentscameunderstudyand,forperiodontaldisease,theimmunestatusandoralhygiene.About5000peopleofallagegroupsunderwentexamination.PoororalhygieneTherewasanobviousdeteriorationintheoralhealthstatusofthesurveyedpopulation.Thelatestdatashowedmoderatetohighlevelsofdentalcaries,ahighlevelofperiodontaldisease,andanincreasingproportionoforalmucosaldiseases.Theaveragenumberofdecayed,missing,orfilled(DMF)teethvariedfrom4.6in15year-oldchildrento19.6intheover65-year-oldagegroup.Oralhygienewaspoor.Thefoodpatternshavechangedtowardsmorerefinedproductsandsweets,whicharedeliveredfromsafeneighbouringregionsandfromabroad.Severalinternationalstudieshaveshownthattheintakeofradionuclidesinfoodstaffsisagrowingriskfactor.From3923samplesofdifferenttypesoffoodmeasuredintheGomelOblastareabetweenAprilandDecember1992,anexcessofradioactivecaesiumwasdetectedin56cases.Theprevalenceofgingivitisand/orperiodontitis,whichwasalmost100%inteenagersandtheadultpopulation,coincidedwiththelackofregularoralhygienepractices.Themostfrequentcomplaintwasgumbleedinganddrynessofthemouth.Thelatterconditionwasobservedin12%of18-year-olds,29%inthe35-44agegroup,and86%in65-year-olds,comparedwith3%,20%,and33%respectivelyinsimilaragegroupssurveyedinnon-contaminatedregionsofthecountry.About17%ofthesurveyedpopulationhadsomeabnormalityororalmucosalesionscomparedwith10%innon-contaminatedareas.Oralhealthservicesforthepopulationincontaminatedareawereinadequateorpoor,duetotheshortageofdentists,dentalequipmentandmaterials,and500Aormoreofdecayedteethwereunfilled.Onaverage,fiveteethwereextractedfromeverytenteenagersaged15years.Inadults,fewteethwerefilledandmostwereextracted,althoughaverageDMFteethwerethesameasinnon-contaminatedzones.Insum,wefoundahighprevalenceofthecommonoralhealthdiseases,poororalhygieneandpoorcareamongthetwomillionpeoplelivingincontaminatedareasofBelarus.Todate,onlyasmallproportionofthepopulationhasmovedtonon-contaminatedareas.ThyroudcancergivesconcernObservationsontheincreaseofsomeoraldiseasesincontaminatedzonesduetoradiationarequestionable,sincenopreciserecordswereavailableintheareabeforetheChernobyldisaster.Nopossibleside-effectsofprolongedlowdosesofradiationonoralstructureshavebeenreported.Nevertheless,theincidenceofthyroudcanceramongchildrenremainsamajorconcerntodayforthehealthauthoritiesinBelarus.Harddentaltissue,particularlytoothenamel,isaccumulatingradioactivityand-withtime-itcouldhaveapotentialpathogeniceffectonoralbiology.Therearealsosignsofthedevelopmentofgastroduodenalpathologyandanincreaseofthyroiddis5ases,certainhaematologicaldiseasesanddisturbancesoftheimmunesystem.AIItheseconditionscouldseriouslyaffecttheoralhealthsituationduetolocalpathogenicfactors,theshortageofservicesandlackofprimaryprevention.Carefultooth-brushingiseffectiveinreducingtheprevalenceofperiodontaldisease,butoralhygieneispoorandhascertainlycontributedtotheperiodontalconditionsobserved.Lackoforalhygieneaidsandtheextremelylowmotivationofthepopulationarethemainobstaclestotheintroductionofaproper,regular,effectiveoralhygieneprogramme.Inconjunctionwithoralhygieneeducationandinstruction,itwouldbenecessarytouselocalanti-inflammatorysubstancesboththroughself-careandwithprofessionalhelp.Asyetwehaveinsufficientevidencetopredictspecificlevelsofdental/oraldiseaseintheareasstudied.However,thefollowingoralhealthproblemscanbeexpected:severeperiodontaldiseasesduetopoororalhygiene,lossofteethduetolackoforalhealthservices,enamelhypoplasiaduetodietaryimbalance,andoralmucosallesionsassymptomsofpoorgeneralhealth.VOCABULARYl.fall-out放射性塵埃，意外的副產品，剩余物2.contaminate(d)污染3.nuclearaccident核事故4.radioactivezone放射性區域(地帶)5.nuclearpowerstation核電站6.disaster災難7.team(s)小分隊(小組)8.strictlycontrolledareas禁區，嚴格控制區9.theafter-effects后效應(影響)10.radiation輻射，放射11.thyroudcancer甲狀腺癌12.thyrouddisorder(s)甲狀腺(功能)紊亂13.autoimmunethyraiditis自動免疫性甲狀腺炎14.systemic(adj.)系統的15.revive(d)(v.)恢復(健康)(使)靈活，蘇醒16.oralhealthproject口腔衛生項目(工程)17.healtheffects健康效應(影響)18.sample(s)樣本19.dosimetry(放射)劑量測定法20.electronspinresonancespectrometry電子旋轉諧振光譜測定法21.highlight(ed)使顯著，突出重點22.riskfactor危險因素23.cofactor(s)協同(共同)因素24.fluorideintake氟化物攝取25.dietarycomponants膳食成份26.immunestatus免疫狀態27.deterioration退化變質、惡化28.oralmucosaldiseases口腔粘膜疾病29.foodpattern(s)食品花樣(種類)30.refinedproducts精制產品(食品)31.deliver(ed)供應(給)32.radionuclides(n.)放射性核素33.foodstuff(s)食品(物)34.radioactivecaesium放射性鉑35.teenager(s)青少年36.coincide(d)與……相同，同時發生37.complaint申訴38.drynessofthemouth口干39.respectively分別地，各自地40.abnormality異常，反常41.oralmucosalesio