ABSTRACT
The use of phosphates in dental glasses and ceramics for the application as biomaterial is merging. Hydroxy apatite is characterized by its solubility in the oral fluids. Studying the effect of the dissolution process of hydroxy apatite added to conventional dental porcelain on its mechanical strength was our aim in this work. Five formulations were prepared from Egyptian raw materials and the mechanical strength of each investigated formulation was measured. It is found that addition of bone ash in amounts not exceeding 10% raised the tensile strength of the investigated dental porcelain. The rate of dissolution of dental porcelain containing bone ash increases with percentage of bone ash added, as the values of mechanical strength were lowered. The pH of the solution was affected by time of immersion. Calcium ions released from the dissolution of tricalcium phosphate readily react with silicon ions giving calcium silicate which render the solution alkaline.
Subject(s)
Biocompatible Materials/chemistry , Dental Porcelain/chemistry , Durapatite/chemistry , Chemistry, Pharmaceutical , Hydrogen-Ion Concentration , Immersion , Materials Testing , Microscopy, Electron, Scanning , Solubility , Surface Properties , Tensile Strength , X-Ray DiffractionABSTRACT
In order to evaluate the corrosion behaviour of some dental alloys to be applied as base-metal for PFM, electrochemical technique and metallurgical investigation were used. Potentiodynamic and potentiostatic tests were carried out under deaerated and aerated conditions in 1% NaCl solution. The results have shown that Ni-Cr alloy has a superior corrosion resistance under deaerated conditions, whereas Co-Cr alloy has a stronger tendency to passivation under aerated conditions. Fe-Cr alloy has demonstrated a poor performance. The results were analyzed on compositional and microstructural bases.
