| Abstract | Cilj ovog rada bio je ispitati ponašanje simuliranih fiksnih ortodontskih naprava u otopinama različitih pH vrijednosti kroz vremensko razdoblje od 28 dana. Konstruirano je 18 uzoraka, a svaki se sastojao od 5 bravica, 1 prstena, žičanog luka i metalnih ligatura, sve Dentaurum (Ispringen, Njemačka). Upotrijebljene su 3 vrste žičanih lukova: nikal-titanski, termo NiTi i lukovi od nehrđajućeg čelika. Naprave su bile in vitro izložene otopini koja je oponašala ljudsku slinu i imala pH 6.75±0.15, te otopini istog sastava koja je dodatno zakiseljena mliječnom kiselinom do pH 3.5±0.15, kako bi se simulirali uvjeti ispod dentobakterijskog plaka. Isti uzorci izlagani su kroz četiri različita vremenska intervala, odnosno u trajanju od 1, 6, 7 i 14 dana. Zbrajanjem otpuštene količine iona u pojedinačnim intervalima izračunano je ukupno otpuštanje nakon 1, 7, 14 i 28 dana. Otopine su analizirane pomoću HRICP/MS uređaja (Center for Trace Analysis, Hattiesburg, SAD). Promatrano je otpuštanje 6 vrsta metalnih iona: titana (Ti), kroma (Cr), nikla (Ni), željeza (Fe),
bakra (Cu) i cinka (Zn). Analiza je pokazala utjecaj sastava i vrste žice, pH vrijednosti otopine i trajanja izloženosti na koncentraciju otpuštenih metalnih iona. Iako su zabilježene koncentracije otpuštenih iona ispod granice toksičnosti, dovoljne su za senzibilizaciju organizma i izazivanje alergijske reakcije. |
| Abstract (english) | The aim of this study was to examine the behaviour of simulated fixed orthodontic appliances in solutions of different pH values through the time period of 28 days. 18 samples were constructed and each consisted of 5 brackets, 1 molar band, an archwire and metal ligatures, all by Dentaurum (Ispringen, Germany). 3 types of archwires have been used: nickel-titanium, thermo NiTi and stainless steel archwires. The appliances were in vitro exposed to artificial saliva and had pH 6.75±0.15, as well as to the solution of the same composition which was further soured with lactic acid up to pH 3.5±0.15 in order to simulate the conditions under the dental plaque. The same samples were immersed during four different time periods, i.e. in the duration of 1, 6, 7 and 14 days. By adding the quantity of the released ions in single intervals the total release after 1, 7, 14 and 28 days has been calculated. The samples were analysed by means of the HR-ICP/MS device (Center for Trace Analysis, Hattiesburg, USA). The release of six different metal ions was observed: titanium (Ti), chromium (Cr), nickel (Ni), iron (Fe), copper (Cu) and zinc (Zn). The analysis has showed the influence of the chemical composition of archwire, of pH value of
solution and of time period on the concentration of the released metal ions. Although the registered concentrations of the released ions are below the toxic level, they are sufficient to cause allergic reactions |
