Original Title:
In vitro μελέτη της επίδρασης της τιμής ph του διαλύματος τεχνητού σάλιου στην απελευθέρωση μεταλλικών στοιχείων των κραμάτων Co-Cr και Ti-6A1-4V, που χρησιμοποιούνται στην κατασκευή των μεταλλικών σκελετών μερικών οδοντοστοιχιών
Summary:
INTRODUCTION: The use of CoCr and Ti6Al4V metal alloys for fabrication of removable partial dentures frameworks have greatly increased in the past decade. One of the main criteria for the selection of the respective alloys for the manufacture of removable prostheses is their resistance to corrosion.The phenomenon of the release of the metal elements expressed by biological safety of the alloys and it is a function of their chemical composition and the type of corrosion.In conditions of reduced pH value of the oral cavity several biological effects may be caused.
PURPOSE: The aim of this study is to investigate in vitro the corrosion behaviour of the CoCr and Ti6Al4V alloys, which are used in construction of metal frame of partial dentures and to detect the type and the concentrations of released metal elements in solution of artificial saliva with different value of pH:3, 5 and 7,2 depending on time of exposure. Also, the aim of the study is to investigate elemental release of metal elements Co and Cr of the casting CoCr alloy and laser sintering CoCr alloy in the solution of artificial saliva with pH:7,2.
MATERIALS AND METHODS: The CoCr alloy specimens (Vitallium III, Dentsply) and Ti6Al4V (Copra Ti-5, Whitepeaks dental solutions) were immersed in artificial saliva solutions pH 3.5 and 7.2 at 37 C during 30 days (test periods: 1, 2, 3, 4, 5, 6, 7, 14, 21, 30 days). In comparative research laser sintering CoCr specimens (Starbond Co, S & S Scheftner) were immersed in artificial saliva solution pH 7.2 at 37 C for 7 days (test periods: 1, 2, 3, 4, 5, 6, 7 days). Samples from all the artificial saliva solutions were analyzed by mass-spectrometry inductively coupled plasma. The concentrations of released metals in solutions considered statistically analyzed with one-way Anova system using IBM SPSS Statistics 21 software program.
RESULTS:In the analysis of the artificial saliva samples showed that the release of metal elements Co and Cr, Ti, Al and V from each alloy.The average concentrations of released metal elements Co of laser sintering CoCr alloy was reduced compared with those of certain metals released alloy casting CoCr. The average concentrations of released metal elements Cr laser sintering CoCr alloy was undetectable.
DISCUSSION: The results of the present study indicate that decrease of the pH value of solutions of artificial saliva with different values of pH was depended on the type of the alloy, composition and pH value of solution and time of exposure.
CONCLUSIONS: In this investigation indicated that:
The decrease of the pH value of artificial saliva caused an increase in concentration of the released metal elements.
The time had influence in the concentration of released metal elements.
The average concentrations of released metals Co and Cr of laser sintering CoCr alloy was reduced compared with those of the alloy casting CoCr.
Keywords:
CoCr metal alloy, Ti6Al4V metal alloy, ion release, artificial saliva, pH value.
