Energy-dispersive x-ray spectrophotometry(EDX) analysis of metalceramic bonds in cobalt-chromium alloys for the fabrication of fix dental restorations

Abstract

Background/Aim. The aim of this research was to determine and quantify changes in the composition of metal-ceramic bond in the base dental alloys submitted to the procedure of multiple casting. Recusing (recycling) of dental alloys is performed very often in the fabrication of fix dental restorations, however, paying no attention to functional durability of the made crown or bridge. Quantitative and qualitative analyses of metal-ceramic bonds should show if recycling of alloys could be justified, that is to estimate the influence of recasting the alloy upon the chemical composition of its bond to ceramics. Methods. This experimental study was performed on Wirebond-C alloy cast multiple times through 12 generations of recycling. A total of 24 samples were evaluated - per six samples in each group as follows: the group A - the first cast, the group B - the third recycling, the group C - the sixth recycling, and the group D - 12th recycling. An Inca X-Sight (Oxford Instruments) and a SEMJEOL microscope type JSM 6460 LV (Tokio, Japan) were used for EDX analysis of the prepared sanples under the following conditions: electron beam frequency of 20,000 impules per second, beam voltage of 10 kV acquisition time of 250 sec, analysed energy range of X-rays energy 0-10 KeV Quantitive EDX analysis of metal ceramic interface was performed by the use of INCA software (Oxford Instruments) in regard to applicable metal and non-metal standards. Results. Each of the metal components of the alloy was decreasing permanently in the composition of metal-ceramic bond with the increase of the number of casting, while ceramic elements were increasing their presence. Individual analysis showed that multiple casting of Wirobond-C alloy reduced a portion of cerium in the metal-ceramic interface to the greatest extent. There was a significant difference between the groups in the composition of metal-ceramic bond after the first casting and the sixth recycling of the alloy (p < 0.001; p < 0.002; t- test independent sample). Conclusion. Recasting of the base cobalt-chromium alloys could not be recommended due to the change in the composition of metal-ceramic interface. Recycling of these alloys brings about significant changes in the metal-ceramic interface with the possible consequences such are weakening of the bond and damage of ceramic during mastication.