Cast titanium is one of the alternatives used in case of allergy to dental alloys. In this study, the possibility of cast titanium ionization when coupled with various dental alloys was investigated from a galvanic point of view by measuring the electric potential. The electric potential was measured versus a reference electrode (Ag/AgCl) in 0.9% NaCl solution, and the results were as follows:
1. The natural potential decreased in order of Type IV-gold alloy, gold-silver-palladium alloy, JIS-class-2-silver alloy, cast titanium, machined titanium, and JIS-class-1-silver alloy.
2. Under experimental conditions, cast titanium showed a higher potential than machined titanium, but when coupled with Type IV-gold alloy, gold-silver-palladium alloy, and JIS-class-2-silver alloy, cast titanium was an anode.
3. The increase in the potential of cast and machined titanium after coupling with cathodic alloys suggested anode polarization and the possibility of titanium iopization.
The results of this experiment suggested that galvanic coupling with other metallic restorations present in the oral cavity should be taken into consideration when titanium casts are used in metal allergy patients.
