Some consequences of repeated casting of Co-Cr dental alloy

The effect of multiple recasting of commercial Co-Cr base dental alloy (Dentalite-C) on its structural characteristics and ion release rates in artificial saliva has been investigated. The number of recasting was once, four and eight times. The as-cast microstructure became uniformer as the number of recasting was increased whereby macro-and micro-hardness and electrical conductivity of the castings decreased. Metallic ion release in artificial saliva was monitored in vitro over the period of 22 weeks at the temperature of 37 degrees C and pH 2.3. Only Co and Fe were evidenced in artificial saliva and their release rates are measured. The ion release rates increases with time. The ion release rate of Fe was larger than Co. The ion release rates increases substantially by increasing the number of recasting