Title UTJECAJ SREDSTAVA ZA
REMINERALIZACIJU CAKLINE NA
KOROZIJU ORTODONTSKIH NIKALTITANSKIH ŽIČANIH LUKOVA
Title (english) INFLUENCE OF ENAMEL
REMINERALIZATION AGENTS ON
CORROSION OF ORTHODONTIC NICKELTITANIUM ARCHWIRES
Author Višnja Katić
Mentor Stjepan Špalj (mentor)
Mentor Helena Otmačić Ćurković (komentor)
Committee member Ivana Brekalo Pršo (predsjednik povjerenstva)
Committee member Sanja Martinez (član povjerenstva)
Committee member Robert Domitrović (član povjerenstva)
Committee member Stjepan Špalj (član povjerenstva)
Committee member Helena Otmačić Ćurković (član povjerenstva)
Granter University of Rijeka Faculty of Medicine (Department of Orthodontics) Rijeka
Defense date and country 2016-09-16, Croatia
Scientific / art field, discipline and subdiscipline BIOMEDICINE AND HEALTHCARE Dental Medicine
Universal decimal classification (UDC ) 616.31 - Stomatology
Abstract Cilj istraživanja bio je ispitati otpornost na koroziju NiTi žica, u simuliranim
uvjetima izloženosti umjetnoj slini i sredstvima za remineralizaciju cakline (MI Paste
Plus, Elmex gelée, Mirafluor-k-gel) te utvrditi može li se otpornost na koroziju znatno
poboljšati nitriranjem i rodiranjem površine.
NiTi žice bez i s prevlakama (nitrirana, rodirana) namočene su u umjetnu slinu
(pH 4,8, 5,1, 5,5, 6,6), na 28 dana. Jednom tjedno po tri uzorka svake vrste žica
namočeni su kroz 5 minuta u remineralizacijska sredstva, isprani destiliranom vodom
te namočeni u umjetnu slinu pH 4,8. Količina otpuštenih iona nikla i titana izmjerena
je pomoću masene spektrometrije. Elektrokemijska testiranja napravljena su na
žicama bez intervencije i nakon 28 dana izloženosti umjetnoj slini (pH 4,8) i
remineralizacijskim sredstvima.
Korozija nikal-titanskih žica ovisna je o vrsti prevlake i koncentraciji
fluorovodične kiseline (HF) u remineralizacijskom sredstvu. Snaga regresijskih
modela za predikciju otpuštanja nikla pod utjecajem koncentracije HF je vrlo velika za
neobloženu (90%) i nitriranu (88%) NiTi žicu te umjerena za rodiranu NiTi (37%).
Predikcijski modeli za otpuštanje iona titana u ovisnosti o koncentraciji HF značajni
su za neobloženu (64%) i nitriranu (62%) NiTi. Količina otpuštenog nikla korelira
linearno značajno s pH umjetne sline samo za neobloženu (48%) NiTi žicu.
Predviđanje otpuštanja iona titana uslijed promjene pH umjetne sline ima najveću
snagu za rodiranu (70%) i neobloženu NiTi (58%), te nešto manju za nitriranu NiTi
(37%). Elektrokemijska testiranja pokazuju razlike između neobložene i nitrirane NiTi
s jedne strane te rodirane NiTi s druge u gustoći korozijske struje, korozijskom
potencijalu, potencijalu pucanja pasivnog sloja i potencijalu repasivacije pretežito
kroz sve medije.
Korozija NiTi žica sa i bez prevlaka korelira s koncentracijom HF u
remineralizacijskim sredstvima. Komercijalno dostupne prevlake na NiTi ortodontskim
žicama ne poboljšavaju otpornost na koroziju, jer prevlake nisu homogene pa dolazi
do pojave lokalizirane jamičaste korozije.
Abstract (english) Objectives: To investigate corrosion resistance of NiTi orthodontic wires in
artificial saliva and enamel remineralisation agents (MI Paste Plus, Elmex gelée,
Mirafluor-k-gel) and determine whether improvement of the corrosion resistance can
be achieved by rhodium (Rh NiTi) and nitride (NNiTi) surface coating on basic wires.
Material and Methods: NiTi, RhNiTi and NNiTi wires were immersed in artificial
saliva (pH 4.8, 5.1, 5.5, 6.6) for 28 days. Three specimen of every wire type were
immersed to remineralisation agents once a week for five minutes, rinsed in distilled
water and immersed to artificial saliva (pH 4.8). Ni and Ti ion release was determined
by the use of mass spectrometry. Electrochemical testing was done on as-received
wires and after immersion in artificial saliva (pH 4.8) and remineralisation agents.
Results: Corrosion of NiTi wires relates to the type of coating and the
concentration of hydrofluoric acid (HF) within the remineralisation agents. Power of
prediction of nickel ion release influenced by HF concentration is considerable for
uncoated (90%) and nitrified (88%) NiTi while moderate for rhodium coated NiTi
(37%). Prediction models for titanium ion release influenced by HF concentration
were significant for uncoated (64%) and nitrified NiTi (62%). Nickel ion release
correlates with the pH of artificial saliva for uncoated NiTi (48%). Prediction models
for titanium ion release influenced by the pH of the artificial saliva is considerable for
rhodium coated (70%) and uncoated (58%) NiTi while moderate for nitrified NiTi
(37%). Electrochemical testing showed differences in uncoated and nitrified NiTi,
when compared to RhNiTi regarding corrosion current density, corrosion potential,
breakdown potential and repassivation potential mainly in all tested media.
Conclusion: Corrosion of NiTi wires without and with coating correlate with
concentration of HF within enamel remineralisation agents. Commercially available
coatings on NiTi orthodontic wires do not improve corrosion resistance. The localised
(pitting) corrosion occurs because the coatings are porous.
Keywords
fluoridi topikalni
kemijska svojstva
korozija
masena spektrometrija
nikal-titanska slitina
ortodontske žice
površinska svojstva.
Keywords (english)
Chemical Properties
Corrosion
Fluorides
Topical
Mass Spectrometry
Language croatian
URN:NBN urn:nbn:hr:184:281300
Study programme Title: Biomedicine Postgraduate (doctoral) study programme Study programme type: university Study level: postgraduate Academic / professional title: doktor/doktorica znanosti, područje biomedicine i zdravstvo (doktor/doktorica znanosti, područje biomedicine i zdravstvo)
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Created on 2022-03-17 11:56:49