I-amalgam yamazinyo isetshenziselwe ukubuyisa amazinyo cishe iminyaka engamakhulu amabili, futhi ukungabaza ngokungqubuzana okubonakalayo kokuhlinzeka insizakalo yokunakekelwa kwezempilo ngento equkethe i-mercury kuqhubeke isikhathi sonke. Bekulokhu kukhona okucashile ngaphakathi emkhakheni wamazinyo wemizwa yokulwa nama-amalgam, inhlangano "engenamercury". Ngenkathi izinkulumo zalowo mqondo sezikhulile eminyakeni yamuva njengoba kuba lula ukufeza amazinyo amahle wokubuyisela enezinhlanganisela, isimo sengqondo sabodokotela bamazinyo maqondana ne-amalgam singafingqwa ngokuthi “akukho lutho olungalungile ngakho ngokwesayensi, asikusebenzisi kakhulu manje. ”

Ukubuza ukuthi ngabe kukhona yini okungalungile noma okungalungile ngokwesayensi nge-amalgam, umuntu kufanele abheke ezincwadini eziningi zokuvezwa, ubuthi kanye nokuhlolwa kobungozi be-mercury. Iningi lalo lingaphandle kwemithombo yolwazi odokotela bamazinyo abavame ukuvezwa kulo. Ngisho nemibhalo eminingi yokuvezwa kwe-mercury kusuka ku-amalgam ikhona ngaphandle kwamajenali wamazinyo. Ukuhlolwa kwale ncwadi enwetshiwe kungakhanyisa ukucabanga okwenziwe ngamazinyo ngokuphepha kwe-amalgam, futhi kungasiza ekuchazeni ukuthi kungani abanye odokotela bamazinyo belokhu bephikisana nokusetshenziswa kwe-amalgam ekwelashweni kwamazinyo okubuyisela esimweni.

Akekho manje ophikisana nokuthi i-amalgam yamazinyo idedela i-metallic mercury endaweni yayo ngandlela thile, futhi kuzothokozisa ukufingqa kafushane obunye bobufakazi balokho kuvezwa. I-toxicology ye-mercury ibanzi kakhulu isihloko sendatshana emfushane, futhi ibuyekezwa kahle kwenye indawo. Isihloko sokuhlolwa kobungozi, nokho, siqonda ngqo enhliziyweni yempikiswano yokuthi i-amalgam iphephile yini, noma cha, ngokusetshenziswa okungavinjelwe kubantu bonke.

Hlobo luni lwensimbi oluku-Dental Amalgam?

Ngoba iyinhlanganisela ebandayo, i-amalgam ayikwazi ukuhlangabezana nencazelo ye-alloy, okumele ibe yingxube yezinsimbi ezakhiwe endaweni encibilikisiwe. Futhi ayikwazi ukuhlangabezana nencazelo yenhlanganisela ye-ionic njengosawoti, okumele ibe nokushintshaniswa kwama-electron okuholela ekitini lama-ion akhokhisiwe. Ihlangabezana kangcono nencazelo ye-inter-metallic colloid, noma i-emulsion eqinile, lapho into ye-matrix ingaphendulwa ngokuphelele, futhi iyatholakala. Umdwebo 1 ukhombisa i-micrograph yesampuli ye-metallurgic yesipolishi yamazinyo ehlotshiswe ngophenyo oluncane. Ngesikhathi ngasinye sokucindezela, amaconsi e-liquid mercury akhishwa. ¹

UHaley (2007)² ukukalwa kokukhishwa kwe-in vitro kwe-mercury kusuka kumasampuli we-single-spill weTytin®, Dispersalloy®, neValiant®, ngayinye enendawo engaphezulu kwe-1 cm2. Ngemuva kokulondolozwa kwezinsuku ezingamashumi ayisishiyagalolunye ukuvumela ukusethwa kokuqala kokuqedwa kuphelele, amasampuli afakwa emanzini acolisisiwe ekamelweni lokushisa, ama-23˚C, futhi awazange akhungatheke. Amanzi acolisisiwe aguqulwa futhi ahlaziywa nsuku zonke izinsuku ezingama-25, kusetshenziswa i-Nippon Direct Mercury Analyzer. IMercury ikhishwe ngaphansi kwale mibandela ngesilinganiso sama-micrograms ayi-4.5-22 nsuku zonke, ngesentimitha skwele. Ukuhlafuna (1991)³ ibike ukuthi i-mercury ichithwe kusuka ku-amalgam yangena emanzini acolisisiwe ngo-37˚C ngesilinganiso esifinyelela kuma-micrograms angama-43 ngosuku, kuyilapho iGross neHarrison (1989)⁴ ibike ama-micrograms angama-37.5 ngosuku kusisombululo sikaRinger.

Ukusatshalaliswa kweMercury Yamazinyo Emzimbeni

Izifundo eziningi, kufaka phakathi izifundo zokuhlolwa kwesidumbu, zikhombise amazinga aphezulu e-mercury ezicubu zomuntu ezinokugcwaliswa kwe-amalgam, ngokungafani nalabo abangazange badalulwe ngokufanayo. Ukwandisa umthwalo we-amalgam kuhlotshaniswa nokwanda kokuhlushwa kwe-mercury emoyeni ophumayo; amathe; igazi; indle; umchamo; izicubu ezahlukahlukene kubandakanya isibindi, izinso, i-pituitary gland, ubuchopho, njll .; i-amniotic fluid, intambo yegazi, i-placenta nezicubu zombungu; i-colostrum nobisi lwebele.⁵

Ukuhlolwa okucaca kakhulu, okudala okukhombisa ukusatshalaliswa kwe-in-vivo ye-mercury kusuka ekugcwalisweni kwe-amalgam kwakuyizifundo “zezimvu nezinkawu” ezazidume kakhulu zikaHahn, et. al. (1989 no-1990).^6,7 Imvu ekhulelwe yanikezwa izithako eziyishumi nambili ze-occlusal amalgam ezazimakwe nge-radioactive ²⁰³I-Hg, into engekho emvelweni, futhi inokuphila okuyingxenye yezinsuku ezingama-46. Ukugcwaliswa kwaqoshwa ngaphandle kokuvaleka, futhi umlomo wesilwane wagcinwa upakishwe futhi wagezwa ukuvimbela ukugwinya okweqile ngesikhathi kusebenza. Ngemuva kwezinsuku ezingamashumi amathathu, yahlatshelwa. I-radioactive mercury yayigxile esibindini, ezinso, emgudwini wokudla nasemathanjeni emihlathi, kepha zonke izicubu, kufaka phakathi izicubu zombungu, zathola ukuvezwa okulinganisekayo. I-autoradiogram yesilwane sonke, ngemuva kokukhishwa kwamazinyo, ikhonjiswa kumfanekiso 2.

Ukuhlolwa kwezimvu kwagxekwa ngokusebenzisa isilwane esidle futhi sihlafune ngendlela ehluke kakhulu kubantu, ngakho-ke iqembu laphinda lesi silingo lisebenzisa inkawu, kwaba nemiphumela efanayo.

25 Skare I, Engqvist A. Ukuchayeka komuntu kwi-mercury nesiliva okukhishwe ekubuyiselweni kwe-amalgam yamazinyo. I-Arch Environ Health 1994; 49 (5): 384-94.

Indima Yokuhlolwa Kwengozi 

Ubufakazi bokuchayeka kuyinto eyodwa, kepha uma "umthamo wenza ubuthi," njengoba sizwile kaningi maqondana nokuvezwa kwe-mercury kusuka ku-amalgam yamazinyo, isinqumo sokuthi yiliphi izinga lokuchayeka okunobuthi nokuthi isifundazwe sinobungozi kubani ukuhlolwa. Ukuhlolwa kweengozi iqoqo lezinqubo ezisemthethweni ezisebenzisa imininingwane etholakala ezincwadini zesayensi, ukuphakamisa amazinga okuchayeka angavumeleka ngaphansi kwezimo ezithile, kuziphathimandla ezibhekele ukulawulwa kwezinhlekelele. Kuyinqubo esetshenziswa kakhulu kwezobunjiniyela, ngokwesibonelo, umnyango wezemisebenzi yomphakathi udinga ukwazi ukuthi kungenzeka yini ukuthi ibhuloho lihluleke ngaphansi komthwalo ngaphambi kokubeka umkhawulo wesisindo kulo.

Kukhona ama-ejensi amaningi abhekele ukulawula ukutholakala kwabantu ezintweni ezinobuthi, i-FDA, i-EPA, ne-OSHA, phakathi kwabo. Bonke bathembele kuzinqubo zokuhlola ubungozi ukusetha imikhawulo yezinsalela ezamukelekayo zamakhemikhali, kufaka phakathi i-mercury, ezinhlanzini nakokunye ukudla esikudlayo, amanzi esiwaphuzayo nasemoyeni esiwuphefumulayo. Lezi zinhlaka bese zibeka imikhawulo ephoqelelwa ngokomthetho ekudalweni kwabantu okuvezwa ngamagama ahlukahlukene, njengomkhawulo wokuchayeka ngokomthetho (REL), umthamo wereferensi (RfD), inkomba yokuhlungwa (RfC), umkhawulo wansuku zonke obekezelelekayo (TDL), njll., konke okusho into efanayo: ukuthi kungakanani ukuvezwa kokuvumela ngaphansi kwezimo i-ejensi ebhekele zona. Leli zinga elivumelekile kumele libe lapho kulindelwe khona ayikho imiphumela emibi yezempilo ngaphakathi kwenani labantu elimbozwe ngaphansi komthethonqubo.

Ukusungula ama-REL

Ukuze sisebenzise izindlela zokuhlola ubungozi besifo esingenzeka se-mercury kusuka ku-amalgam yamazinyo, kufanele sinqume umthamo we-mercury abantu abadalulwa kuwo kusukela ekugcwalisweni kwabo, bese siqhathanisa lokho namazinga okuphepha asunguliwe alolo hlobo lokuchayeka. I-toxicology ye-mercury iyabona ukuthi imiphumela yayo emzimbeni incike kakhulu ezinhlotsheni zamakhemikhali ezithintekayo, kanye nendlela yokuchayeka. Cishe wonke umsebenzi we-amalgam toxicity uthatha ukuthi izinhlobo ezinobuthi ezinkulu ezithintekayo yi-metallic mercury vapor (Hg˚) ekhishwa yizifaki, ezihogelwe emaphashini futhi zimunce ngesilinganiso esingu-80%. Ezinye izinhlobo nemizila kuyaziwa ukuthi ziyabandakanyeka, kufaka phakathi i-metallic mercury encibilikiswe ngamathe, izinhlayiya ezi-abraded nemikhiqizo yokugqwala eginywayo, noma i-methyl mercury ekhiqizwa yi-Hg˚ ngamagciwane emathumbu. Kutholakale izindlela ezingajwayelekile kakhulu, njengokufakwa kwe-Hg˚ ebuchosheni nge-olitactic epithelium, noma ukubuyisela emuva ukuthuthwa kwe-axonal ye-mercury kusuka emhlathini kuya ebuchosheni. Lokhu kuvezwa kungenzeka kungobuningi obungaziwa, noma kucatshangwa ukuthi kuncane kakhulu kunokudonswa ngomlomo, ngakho-ke inqwaba yocwaningo lwe-amalgam mercury igxile lapho.

Isistimu yezinzwa ephakathi icatshangwa ukuthi iyisitho esibhekiswe ebucayi kakhulu sokuchayeka komphunga we-mercury. Imiphumela enobuthi esungulwe kahle ezinso nasemaphashini kucatshangwa ukuthi inemingcele ephakeme yokuchayeka. Imiphumela ngenxa ye-hypersensitivity, autoimmunity nezinye izindlela zohlobo lokungezwani komzimba azikwazi ukubalwa ngamamodeli okuphendula umthamo, (okucela umbuzo, ukuthi kuvame kangakanani ukungezwani komzimba ne-mercury, empeleni?) Ngakho-ke, abacwaningi nezinhlangano ezifuna ukusungula ama-RELs aphansi Ukuvezwa okungapheli kwe-Hg˚ kubheke izindlela ezahlukahlukene zemiphumela ye-CNS. Izifundo ezimbalwa ezibalulekile (ezifingqiwe kuthebula 1) zishicilelwe eminyakeni edlule exhuma ubuningi bokuchayeka komphunga we-mercury nezimpawu ezilinganisekayo zokungasebenzi kahle kwe-CNS. Lezi yizifundo ososayensi abathembele kuzo.

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Ithebula 1. Izifundo ezisemqoka ezisetshenzisiwe ukubala ukugxila kokukhomba komswakama we-metallic mercury, okuvezwe njengama-micrograms nge-cubic meter yomoya. I-asterix * isho ukugxila komoya okuthathwe ngokuguqula amanani egazi noma omchamo alingane nomoya ngokuya ngezinto eziguqukayo ezivela kuRoels et al (1987).

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Umkhuba wokuhlola ubungozi uyaqaphela ukuthi idatha yokuvezwa kanye nomphumela eqoqelwe umuntu omdala, owesilisa okweqile, abasebenzi abasezikhundleni zomsebenzi abakwazi ukusetshenziswa ngendlela yabo eluhlaza njengokukhombisa amazinga aphephile kuwo wonke umuntu. Kunezinhlobo eziningi zokungaqiniseki kudatha:

• I-LOAEL vs. NOAEL. Ayikho idatha yokuvezwa eqoqwe ezifundweni ezisemqoka ebikiwe ngendlela ekhombisa ijika lempendulo elicacile lemiphumela ye-CNS elinganisiwe. Ngakho-ke, azikhombisi umthamo ocacile wokqala kwemiphumela. Ngamanye amagama, akukho ukuzimisela kwe- "No-Observed-Adverse-Effect-Level" (NOAEL). Ucwaningo ngalunye lukhomba ku- "I-Lowest-Obsited-Adverse-Effect-Level" (i-LOAEL), engathathwa njengecacile.
• Ukwehluka komuntu. Kunamaqembu amaningi abantu abucayi ngokwengeziwe kubantu abaningi: izinsana nezingane ezinokuqina okubucayi okukhulayo kwezinhlelo zemizwa nesisindo somzimba esiphansi; abantu abanokuyekethisa kwezokwelapha; abantu abanesifiso sokuthola ukuzwela okwandisiwe abesifazane abaneminyaka yobudala bokubeletha nokunye umehluko ohlobene nobulili; asebekhulile, ukubala abambalwa. Umehluko wokusebenzisana ongabaliwe kudatha wenza ukungaqiniseki.
• Idatha yokuzala neyentuthuko. Amanye ama-ejensi, njengeCalifornia EPA, agcizelela kakhulu idatha yokuzala neyentuthuko, futhi axhume izinga elengeziwe lokungaqiniseki ezibalweni zawo lapho lishoda khona.
• Idatha yezinhlobo eziphakathi. Ukuguqula idatha yocwaningo lwezilwane kulwazi lomuntu akukaze kuqonde ngqo, kepha ukucatshangelwa kwalesi sici akusebenzi kulokhu, ngoba izifundo ezibalulekile ezikhonjiwe lapha zonke zithinta izifundo zabantu.

Ama-REL ashicilelwe wokuchayeka kwemfucumfucu engapheli emiphakathini jikelele afingqiwe kuThebula 2. Ama-RELs enzelwe ukulawula ukuvezwa kwabantu bonke abalwa ukuqinisekisa ukuthi ngeke kube khona ukulindela okulindelekile kwemiphumela emibi yezempilo kunoma ngubani, ngakho-ke ukuvezwa okuvumelekile kuncishisiwe kusuka amazinga wemphumela aphansi kakhulu abonwe yi-arithmetic "izici zokungaqiniseki" (UF). Izici zokungaqiniseki azinqunywa yimithetho enzima futhi esheshayo, kepha ngenqubomgomo - ukuthi i-ejensi yokulawula iqaphela kangakanani, nokuthi izethemba kangakanani kwimininingwane.

Endabeni ye-US EPA, ngokwesibonelo, izinga lomphumela (9 µg-Hg / cubic meter air) lincishisiwe ngesici esingu-3 ngenxa yokuthembela ku-LOAEL, nangesici esingu-10 ukubhekelela ukwehluka kwabantu, i-UF ephelele engama-30. Lokhu kubangela umkhawulo ovunyelwe womoya ongu-0.3 µg-Hg / cubic meter. ⁸

ICalifornia EPA yengeze i-UF eyengeziwe ye-10 ngokushoda kwemininingwane yokuzala neyentuthuko ye-Hg0, okwenza umkhawulo wayo uphindwe kayishumi njengobukhali, umoya ongu-0.03 µg Hg / cubic meter. ⁹

URichardson (2009) ukhombe isifundo seNgim et al¹⁰ njengefaneleke kakhulu ekuthuthukiseni i-REL, ngoba iveze odokotela bamazinyo besilisa nabesifazane eSingapore, abangavezwa njalo emazingeni aphansi omphunga we-mercury ngaphandle kokuba khona kwe-chlorine gas (bheka ngezansi). Usebenzise i-UF ye-10 kune-3 ye-LOAEL, ephikisa ngokuthi izinsana nezingane zizwela kakhulu kunesici esingu-3 esingaziphendulela. Efaka i-UF engu-10 okwehlukahluka komuntu, kuma-UF esewonke ayi-100, wancoma ukuthi abezempilo eCanada babeke iREL yabo yomphunga we-mercury ongapheli ku-0.06 µg Hg / cubic meter air.¹¹

I-Lettmeier et al (2010) ithole inhloso ebaluleke kakhulu yezibalo (i-ataxia yesango) kanye nemiphumela ye-subjective (sadness) kubavukuzi abancane begolide e-Afrika, abasebenzisa i-mercury ukuhlukanisa igolide ne-ore echotshoziwe, emazingeni aphansi okuvezwa, 3 µg Hg / cubic meter omoya. Ngokulandela i-US EPA, basebenzise uhla lwe-UF olungu-30-50, futhi baphakamisa ukuthi i-REL iphakathi kuka-0.1 no-0.07 µg Hg / umoya wamamitha ayi-cubic.¹²

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Ithebula 2. Ama-REL ashicilelwe wokuchayeka ezingeni eliphansi, umhosha ongapheli we-Hg0 kubantu bonke, ngaphandle kokuvezwa komsebenzi. * Ukuguqulwa kumthamo omuncu, µg Hg / kg-day, kusuka eRichardson (2011).

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Izinkinga ngama-RELs

I-EPA yase-US igcine ukubuyekeza i-mercury vapor REL (0.3 Hg Hg / cubic meter air) yayo ngo-1995, futhi yize bakuqinisekisa ngo-2007, bayavuma ukuthi kushicilelwe amaphepha amasha angabakholisa ukuthi babuyekeze i-REL phansi. Amaphepha amadala kaFawer et al (1983) ¹³ noPiikivi, et al (1989 a, b, c)^{14, 15, 16}, kuncike kakhulu kuzilinganiso zokuchayeka kwe-mercury nemiphumela ye-CNS kubasebenzi be-chloralkali. I-Chloralkali inqubo yekhulu leshumi nesishiyagalolunye lomkhakha wamakhemikhali lapho usawoti usawoti untanta phezu koqweqwe oluncane lwe-liquid mercury, kanye ne-hydrolyzed ngamandla kagesi ukukhiqiza i-sodium hypochlorite, i-sodium hydroxide, i-sodium chlorate, i-chlorine gas, neminye imikhiqizo. I-mercury isebenza njengenye yama-electrode. Abasebenzi ezitshalweni ezinjalo abadalulwanga kuphela kwi-mercury esemoyeni, kodwa nakwegesi ye-chlorine.

Ukuvezwa okuhambisanayo komphunga we-mercury negesi le-chlorine kuguqula amandla okuvezwa kwabantu. I-Hg˚ ihlanganiswe ngokwengxenye ne-chlorine emoyeni iye ku-Hg²⁺, noma i-HgCl₂, eyehlisa ukungena kwayo emaphashini, futhi iguqula ngokuphawulekayo ukusatshalaliswa kwayo emzimbeni. Ngokuyinhloko, i-HgCl₂ ukumunca umoya ngamaphaphu akungeni kumaseli, noma ngesithiyo segazi nobuchopho, kalula njenge-Hg˚. Isibonelo, uSuzuki et al (1976)¹⁷ ikhombise ukuthi abasebenzi abadalulwe ku-Hg˚ bebodwa babenesilinganiso se-Hg kumaseli abomvu egazini kuya ku-plasma ka-1.5 -2.0 kuya ku-1, kuyilapho abasebenzi be-chloralkali bedalulwe kuwo womabili ama-mercury ne-chlorine babenenani le-Hg kuma-RBCs kuya ku-plasma ka-0.02 kuya ku-1, cishe engaphansi ngokuphindwe kayikhulu ngaphakathi kwamangqamuzana. Lesi simo singadala ukuthi i-mercury ihlukane kakhulu nezinso kunobuchopho. Inkomba yokuchayeka, i-mercury yomchamo, ibingafana kuzo zombili izinhlobo zabasebenzi, kepha abasebenzi be-chloralkali bazoba nomphumela omncane kakhulu we-CNS. Ngokuhlola ikakhulukazi izifundo zabasebenzi be-chloralkali, ukuzwela kwe-CNS ekuvezweni kwe-mercury kungabukelwa phansi, futhi ama-RELs asuselwa kulezi zifundo azobhekwa ngokweqile.

Phakathi kwamaphepha amasha kunomsebenzi ka-Echeverria, et al, (2006)¹⁸ othola imiphumela ebalulekile ye-neurobehavioral ne-neuropsychological kodokotela bamazinyo nabasebenzi, ngaphansi kwezinga lomoya elingama-25 µg Hg / cubic meter, esebenzisa izivivinyo eziqiniswe kahle. Nakulokhu, akukho mkhawulo otholakele.

Ukufaka ama-Mercury RELs ku-Dental Amalgam

Kunokwehluka emibhalweni emayelana nomthamo wokuvezwa kwe-mercury kusuka ku-amalgam, kepha kunokuvumelana okubanzi kwezinye izinombolo ezithintekayo, ezifingqiwe kuThebula 3. Kuyasiza ukugcina lezi zibalo eziyisisekelo engqondweni, njengoba bonke ababhali bezisebenzisa ekubaleni kwazo . Kuyasiza futhi ukugcina engqondweni ukuthi le mininingwane yokuchayeka ingama-analogs kuphela okuchayeka ebuchosheni. Kunemininingwane yabantu yezilwane neyemuva kokuhlolwa komzimba, kepha akukho ekuhambeni kwangempela kwe-mercury ebuchosheni babasebenzi ababandakanyeka kulezi zifundo.

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Ithebula 3. izinkomba:

• a- Mackert noBerglund (1997)
• b- Skare and Engkvist (1994)
• c- kubuyekezwe eRichardson (2011)
• d-Roels, et al (1987)

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Maphakathi nawo-1990 kwashicilelwa ukuhlolwa okwehlukene kokuchayeka kwe-amalgam nokuphepha. Lowo onethonya elikhulu ezingxoxweni emphakathini wamazinyo wabhalwa nguH. H. Rodway Mackert noAnders Berglund (1997)¹⁹, oprofesa bamazinyo eMedical College yaseGeorgia, naseUmea University eSweden, ngokulandelana. Leli yiphepha lapho kwenziwa khona isimangalo sokuthi kungathatha indawo efinyelela ku-450 ye-amalgam ukusondela kumthamo onobuthi. Laba babhali bacaphune amaphepha abethambekele ekwehliseni umphumela we-chlorine ekumungeni kwe-mercury yasemkhathini, futhi basebenzise umkhawulo wokuchayeka emsebenzini, (otholwe abesilisa abadala abaveze amahora ayisishiyagalombili ngosuku, izinsuku ezinhlanu ngesonto), wama-25 µg-Hg / cubic imitha lomoya njenge-de-facto REL yabo. Abakubonanga ukungaqiniseki kuleso sibalo njengoba kuzosebenza kubantu bonke, kufaka phakathi izingane, ezizodalulwa amahora angama-24, izinsuku eziyisikhombisa ngesonto.

Ukubalwa kuhamba kanjena: izinga eliphansi kakhulu elibonwe lokuthuthumela ngenhloso phakathi kwabasebenzi besilisa abadala, ikakhulukazi abasebenzi be-chloralkali, kwakungu-25 µg-Hg / cubic meter air elingana nezinga lomchamo cishe lama-30 µg-Hg / gr-creatinine. Ukubalwa kwezinga elincane le-urine mercury eyisisekelo etholakala kubantu ngaphandle kokugcwaliswa, nokuhlukanisa ama-30 byg ngomnikelo womhlaba ngamunye kumchamo we-mercury, i-0.06 µg-Hg / gr-creatinine, umphumela umayelana nezindawo ezingama-450 ezidingekayo ukufinyelela lelo zinga .

Phakathi naleso sikhathi, uG. isiphetho esihluke kakhulu kunesikaMackert noBerglund. Kusetshenziswa idatha yemiphumela yokuchayeka nezici zokungaqiniseki ngokuhambisana nalezo okuxoxwe ngazo ngenhla, baphakamisela iCanada i-REL ye-mercury vapor ye-1995 µg Hg / kg-day. Ngokuthatha indawo engu-0.014 ngokugcwaliswa ngakunye, babala ububanzi benombolo yokugcwaliswa engeqi kulelo zinga lokuvezwa kwamaqembu eminyaka yobudala ehlukene, ngokususelwa kunesisindo somzimba: izinsana, 2.5-0; izingane, 1-0; intsha, 1-1; abadala, 3-2; abadala, 4-2. Ngokuya ngalezi zinombolo, i-Health Canada ikhiphe uchungechunge lwezincomo zokunqanda ukusetshenziswa kwe-amalgam, okuye kwanakwa kabanzi lapho kwenziwa.^{20, 21}

Ngo-2009, i-US Food and Drug Administration, ngaphansi kwengcindezi evela enkantolo yezakhamizi, yaqedela ukuhlukaniswa kwayo kwe-amalgam yamazinyo eseyenziwe ngaphambili, inqubo eyayigunyazwe yiCongress ngo-1976.²² Bahlukanise i-amalgam njengedivayisi Yesigaba II enezilawuli ezithile zokulebula, okusho ukuthi bakutholile kuphephile ukusetshenziswa komuntu wonke. Izilawuli zokulebula bezihloselwe ukukhumbuza odokotela bamazinyo ukuthi bazophatha idivayisi equkethe i-mercury, kepha bekungekho mandla okudlulisela lolo lwazi ezigulini.

Umbhalo wokuhlukaniswa kwe-FDA wawuyiphepha elinemininingwane eli-120 elinamakhasi ayi-0.3 izimpikiswano zawo ezazincike kakhulu ekuhloleni ubungozi, ngokuqhathanisa ukuvezwa kwe-amalgam mercury ne-standard EPA engu-XNUMX µg-Hg / cubic meter air standard. Kodwa-ke, ukuhlaziywa kwe-FDA kusebenze kuphela okushiwo ukutholakala kwabantu base-US ku-amalgam, hhayi uhla oluphelele, futhi, ngokumangazayo, akulungisanga umthamo wesisindo somzimba ngamunye. Yayiphatha izingane sengathi zingabantu abadala. La maphuzu aphikiswa ngokuqinile “ezicelweni eziningi zokucabangisisa kabusha” ezithunyelwe ngamaqembu ezakhamizi nezingcweti ku-FDA ngemuva kokushicilelwa kokwahlukaniswa. Izicelo zazibhekwa njengezibambisene ngokwanele yizikhulu ze-FDA ukuthi i-ejensi yathatha isinyathelo esingavamile sokuhlanganisa iphaneli lochwepheshe ukuze kubhekwe kabusha amaqiniso okuhlolwa kobungozi bayo.

URichardson, manje ongumxhumanisi ozimele, wacelwa ngabaningana babafaki bezicelo ukuthi babuyekeze ukuhlolwa kwakhe kwasekuqaleni kobungozi. Ukuhlaziywa okusha, kusetshenziswa imininingwane eningiliziwe ngenani lamazinyo agcwalisiwe kubantu base-US, bekuyisikhungo sokuxoxisana engqungqutheleni yephaneli lochwepheshe le-FDA likaDisemba, 2010. (Bheka uRichardson et al 2011⁵).

Imininingwane ngenani lamazinyo agcwalisiwe kubantu baseMelika ivela kuNational Health and Nutrition Examination Survey, inhlolovo ezweni lonke yabantu ababalelwa ku-12,000 abaneminyaka engama-24 kuya phezulu, eyagcina ukuqedwa ngo-2001-2004 yiNational Center for Health Statistics, isigaba Yezikhungo Zokulawulwa Nokuvimbelwa Kwezifo. Kuyinhlolovo evumelekile yezibalo emele bonke abantu base-US.

Ucwaningo luqoqe idatha ngenani lezindawo ezigcwalisiwe zamazinyo, kepha hhayi kokugcwaliswayo. Ukulungisa lokhu kushoda iqembu likaRichardson liveze izimo ezintathu, konke kuphakanyiswe yimibhalo ekhona: 1) zonke izindawo ezigcwele zazingama-amalgam; 2) Ama-50% wezindawo ezigcwalisiwe kwakungu-amalgam; 3) Izifundo ezingama-30% bezingenayo i-amalgam, kuthi ezinye ezingama-50% zibe yi-amalgam. Ngaphansi kwesimo sesi-3, esithatha inani elincane kakhulu lokugcwaliswa kwe-amalgam, izindlela ezibaliwe zomthamo wansuku zonke we-mercury yilezi:

Ojahidada 0.06 µg-Hg / kg-usuku
Izingane 0.04
Intsha 0.04
Abantu abadala 0.06
Abadala 0.07

Wonke lawa mazinga wedosi afuthwe nsuku zonke ahlangabezana noma adlula umthamo wansuku zonke we-Hg0 ohlotshaniswa nama-REL ashicilelwe, njengoba kuboniswe kuThebula 2.

Inani lezinhlanganisela ze-amalgam ebengeke lidlule i-REL yase-US EPA ka-0.048 µg-Hg / kg-day ibaliwe, ukuze izingane ezisacathula, izingane kanye nentsha ibe yizindawo ezi-6. Kwabasha asebekhulile, abadala nabadala, yizindawo eziyi-8. Ukuze weqe i-REL yaseCalifornia EPA, lezo zinombolo zizoba indawo engu-0.6 no-0.8.

Kodwa-ke, lokhu kuvezwa okujwayelekile akulubeki lonke udaba, futhi akubonisi ukuthi bangaki abantu abadlula umthamo “ophephile”. Ehlola lonke uhla lwezinombolo zamazinyo agcwalisiwe kubantu, uRichardson ubala ukuthi njengamanje kuzoba khona abantu baseMelika abayizigidi ezingama-67 ukuvezwa kwe-amalgam mercury okudlula i-REL ephoqelelwa yi-US EPA. Uma kusetshenziswe i-California REL eqinile, leyo nombolo ibingaba yizigidi eziyi-122. Lokhu kuqhathaniswa nokuhlaziywa kwe-FDA ka-2009, okubheka kuphela inani elishoyo lamazinyo agcwalisiwe, ngaleyo ndlela livumele ukutholakala kwabantu ukuba balingane ngaphansi kwe-EPA REL yamanje.

Ukuze kukhuliswe leli phuzu, uRichardson (2003) wakhomba amaphepha ayi-XNUMX ezincwadini ezazethula ukulinganiselwa kobubanzi bomthamo wokuvezwa kwe-mercury kusuka ekugcwalisweni kwe-amalgam. ²³ Umdwebo 3 ubabonisa, kanye nedatha ephepheni lakhe lika-2011, emele ngesimo sokuqhafaza isisindo sobufakazi. Imigqa ebomvu eme mpo ifaka okulingana nomthamo weREL yaseCalifornia EPA, imingcele eqine kakhulu yokulawulwa kokuvezwa komphunga we-mercury, kanye neREL yase-US EPA, ethambe kakhulu. Kusobala ukuthi abaphenyi abaningi abamaphepha abo amelwe kuMdwebo 3 bangaphetha ngokuthi ukusetshenziswa okungavinjelwe kwe-amalgam kungaholela ekuvezweni ngokweqile kwe-mercury.

Ikusasa Le-Amalgam Yamazinyo

Njengalokhu kubhalwa, ngoJuni, 2012, i-FDA ibingakamemezeli isiphetho sezingxoxo zayo mayelana nesimo sokulawulwa kwe-amalgam yamazinyo. Kunzima ukubona ukuthi le ejensi izokwazi kanjani ukunikeza i-amalgam ilambu eliluhlaza ukusetshenziswa okungavinjelwe. Kusobala ukuthi ukusetshenziswa okungavinjelwe kungadalula abantu kwi-mercury ngaphezu kwe-REL ye-EPA, umkhawulo ofanayo lapho imboni yamandla yamalahle iphoqelelwa ukuhambisana nayo, nokusebenzisa izigidigidi zamaRandi ukukwenza. I-EPA ilinganisela ukuthi kusukela ngo-2016, ukwehlisa ukukhishwa kwe-mercury, kanye nomsizi kanye namagesi e-acid, kungonga u- $ 59 billion kuya ku- $ 140 billion ezindlekweni zezempilo zonyaka, kuvimbele ukufa kwabantu abangu-17,000 ngaphambi kwesikhathi ngonyaka, kanye nezifo nezinsuku zokusebenza ezilahlekile.

Ngaphezu kwalokho, umehluko phakathi kwendlela kaMackert neBerglund yokuphepha kwe-amalgam kanye nendlela yeRichardson igcizelela ukwehlukaniswa okuye kwaphawula "izimpi ze-amalgam" zomlando. Noma sithi "ngeke kulimaze muntu," noma "kuzolimaza omunye umuntu." Kulesi sikhathi samazinyo okubuyiselwa esimweni esihle esenziwe ngenhlaka, lapho inani elandayo labodokotela bamazinyo lisebenza ngokuphelele ngaphandle kwe-amalgam, sinethuba elilula lokuphila ngomthetho wokuqapha. Isikhathi silungile sokuthumela i-amalgam yamazinyo endaweni yayo ehlonishwayo emlandweni wamazinyo, bese usidedela. Kumele siqhubeke nokuncoma kwayo - sithuthukise izindlela zokuvikela iziguli nabasebenzi bamazinyo ekuchayekeni okweqile lapho kususwa ukufakwa; vikela abasebenzi ekudalweni okuphezulu kwesikhashana, okufana nokwenzeka lapho kuthululwa izingibe zezinhlayiyana.

I-mercury yamazinyo kungaba yingxenye encane yenkinga yomhlaba wonke ye- ukungcoliswa kwe-mercury, kepha kuyingxenye thina odokotela bamazinyo esibhekele yona ngqo. Kufanele siqhubeke nemizamo yethu yokuvikela ezemvelo, ukuhlukanisa amanzi angcolile athwele imercury emfudlaneni wendle, yize siyeka ukuwasebenzisela ukukhathazeka ngempilo yabantu.

UStephen M. Koral, i-DMD, i-FIAOMT

_________

Ukuze uthole imininingwane ephelele ngale ndaba, bheka "Ukuhlolwa Kobungozi be-Amalgam 2010" futhi "Ukuhlolwa Kobungozi be-Amalgam 2005. "

Sisekugcineni, le ndatshana yanyatheliswa ngohlelo lukaFebhuwari, 2013 lwe- “Ukuhlanganiswa Kwemfundo Eqhubekayo Kwezamazinyo." 

Ingxoxo eyengeziwe yokuhlolwa kobungozi maqondana ne-amalgam yamazinyo nayo ingafundwa ku- "I-IAOMT Position Paper elwa ne-Dental Amalgam. "

Okubhekwayo

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I-7 Hahn LJ, Kloiber R, Leininger RW, Vimy MJ, Lorscheider FL. 1990. Ukucabanga komzimba wonke kokusatshalaliswa kwe-mercury okukhishwe ekugcwalisweni kwamazinyo kwezicubu zenkawu. I-FASEB J, 4 (14): 3256-60.

8 USEPA (Inhlangano Yezokuvikelwa Kwezemvelo yase-United States). 1995. IMercury, i-elemental (CASRN 7439-97-6). Uhlelo Oludidiyelwe Lobungozi Bengozi. Kugcine ukubuyekezwa ngoJuni 1, 1995. Ku-inthanethi ku:  http://www.epa.gov/ncea/iris/subst/0370.htm

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12 Lettmeier B, Boese-O'Reilly S, Drasch G. 2010. Isiphakamiso sokubuyekezwa kwezithenjwa (RfC) komhwamuko we-mercury kubantu abadala. ISci Total Environ, 408: 3530-3535

13 Fawer, RF, de Ribaupeirre, Y., Buillemin, MP et al. 1983. Ukukalwa kokuthuthumela kwesandla okubangelwa ukuvezwa yizimboni kwi-metallic mercury. Br. UJ. Ind. Med., 40: 204-208

14 UPiikivi, L., 1989a. Izimo zenhliziyo zemithambo yegazi kanye nokuchayeka okuphansi kwesikhathi eside kumphunga we-mercury. Int. I-Arch. Umsebenzi. Environ. Impilo 61, 391-395.

15 UPiikivi, L., Hanninen, H., 1989b. Izimpawu ezizimele nokusebenza kwengqondo kwabasebenzi be-chlorine-alkali. Scand. J. Umsebenzi Environ. Impilo 15, 69-74.

16 UPiikivi, L., Tolonen, U., 1989c. Ukutholwa kwe-EEG kubasebenzi be-chlor-alkali kubhekane nokuchayeka okuphansi kwesikhathi eside kumphunga we-mercury. Br. J. Ind. IMed. 46, 370-375.

17 Suzuki, T., Shishido, S., Ishihara, N., 1976. Ukusebenzisana kwe-inorganic ne-organic mercury emzimbeni wabo emzimbeni womuntu. Int. I-Arch. Umsebenzi. Ezempilo.Impilo 38, 103-113.

18 Echeverria, D., Woods, JS, Heyer, NJ, Rohlman, D., Farin, FM, Li, T., Garabedian, CE, 2006. Ukuhlangana phakathi kwe-polymorphism yezofuzo ye-coproporphyrinogen oxidase, ukuvezwa kwamazinyo e-mercury nempendulo ye-neurobehavioral kubantu. I-Neurotoxicol. I-Teratol. 28, 39-48.

19 Mackert JR Jr. noBerglund A. 1997. Ukuvezwa kweMercury kusuka ekugcwalisweni kwamazinyo e-amalgam: umthamo omuncu kanye namandla okuba nemiphumela emibi yezempilo. I-Crit Rev Oral Biol Med 8 (4): 410-36

20 Richardson, GM 1995. Ukuhlolwa kokuvezwa kwe-mercury nezingozi ezivela ku-amalgam yamazinyo. Ilungiswe egameni leBureau of Medical Devices, Health Protection Branch, Health Canada. 109p. Yangomhla ka-Agasti 18, 1995. Kusemgqeni ku: http://dsp-psd.communication.gc.ca/Collection/H46-1-36-1995E.pdf   or http://publications.gc.ca/collections/Collection/H46-1-36-1995E.pdf

21 Richardson, GM noM. Allan. 1996. Ukuhlolwa kweMonte Carlo Kokuvezwa KweMercury Nezingozi Ezivela Kumazinyo Amalgam. Ukuhlolwa Kobungozi Bomuntu Nemvelo, 2 (4): 709-761.

22 US FDA. 2009. Umthetho Wokugcina We-Amalgam Wamazinyo. Kulayini ku: http://www.fda.gov/MedicalDevices/ProductsandMedicalProcedures/DentalProducts/DentalAmalgam/ucm171115.htm.

23 Kunwetshiwe kusuka ku: Richardson, GM 2003. Ukuhogela i-mercury engcoliswe yizinhlayiyana zezinhlayiya zamazinyo: ingozi enganakwa yomsebenzi. Ukuhlolwa Kobungozi Bomuntu Nemvelo, 9 (6): 1519 - 1531. Umfanekiso onikezwe umbhali ngokuxhumana komuntu siqu.

24 Roels, H., Abdeladim, S., Ceulemans, E. et al. 1987. Ubudlelwano phakathi kokugxila kwe-mercury emoyeni nasegazini noma emchameni wabasebenzi bavezwa umphunga we-mercury. U-Ann. Umsebenzi. I-Hyg., 31 (2): 135-145.

25 Skare I, Engqvist A. Ukuchayeka komuntu kwi-mercury nesiliva okukhishwe ekubuyiselweni kwe-amalgam yamazinyo. I-Arch Environ Health 1994; 49 (5): 384-94.