Title: In vivo kinetic release of five metal ions (iron, titanium, nickel, copper and chromium) from fixed orthodontic alloys in Erbil city-Kurdistan region or Iraq

Abstract

The orthodontic kinetic release of metal ions was studied in order to have a conclusive in-vivo data for variation of metal ion concentrations with time (month) at normal oral temperature 37°C, which affects the saliva quality and quantity, pH, chemical and physical characteristics of food and liquid. The superficial break down and release of metals from the alloy brackets were investigated by scanning electron microscopy (SEM) and energy dispersive X-Ray spectroscopy (EDS) images. The kinetic release experiment of the metal ion concentrations (Nickel, Chromium, Titanium, Iron, and copper) in the saliva uptakes follow a pseudo-second-order kinetic model, the release rate of metal ions was in series Fe2+ > Ti2+ > Ni2+ > Cu2+ > Cr3+, and the highest saliva pH and flow rate were detected after one month for fixed orthodontics appliance was (7.16  0.55) and (0.88  0.55) respectively.