Objectives: This study investigated the tensile strength of experimental Ti-Cu-Cr alloys indicated for use in crown restoration.  Methods: The alloys tested were: Ti-5.0Cu-Cr and Ti-10.0Cu-Cr (0.5, 1.0, 3.0 and 5.0 mass% Cr) and controls of Ti-5.0Cu and Ti-10.0Cu.  Dumbbell-shaped specimens (gauge length: 15 mm; diameter: 3.0 mm) of each metal were cast in an argon-arc melting/pressure casting machine (Cyclarc II, J. Morita, Japan) using an Al₂O₃/MgO-based investment material (Titavest CB, J. Morita, Japan).  The specimens whose porosity could not be recognized by radiographs were subjected to mechanical testing.  The specimens were subjected to a tensile load at a crosshead speed of 1.0 mm/min.  The yield strength (YS) at 0.2% offset and elongation (E) was obtained from a stress-strain curve plot (n=5).  The results [mean (SD)] were analyzed using t-test analysis. 

	Ti-5.0 Cu					Ti-10.0 Cu
Cr mass %	0	0.5	1.0	3.0	5.0	0	0.5	1.0	3.0	5.0
YS (MPa)	535(33)	535(17)	560(8)	675(17)	936(45)	719(33)	706(28)	750(23)	877(14)	985(33)
E (%)	5.3(0.6)	5.6(0.5)	5.6(1.0)	3.2(0.2)	1.4(0.5)	1.9(0.6)	2.8(0.4)	2.7(0.4)	2.6(0.6)	1.6(0.2)

Results: Both the Ti-5.0Cu and Ti-10.0Cu alloys with a Cr content of more than 3.0% exhibited higher yield strength (p<0.05) than each of the Ti-Cu alloys, and no significant differences (p>0.05) were found among those with a Cr content of less than 1.0%.  The Ti-5.0Cu alloys with a Cr content of more than 3.0% exhibited significantly lower elongation (p<0.05) than did those with a Cr content of less than 1.0%.  The Ti-10.0Cu-Cr alloys with a Cr content of less than 1.0% exhibited significantly higher elongation (p<0.05) than did the Ti-10.0Cu alloys.  There was, however, no significant statistical difference (p>0.05) among the other Ti-10.0Cu-Cr alloys.  Conclusions: Alloys with only a slight increase in Cr content in Ti-Cu contributes to an increase in ductility.