Effectiveness of cast-joined Ni-Cr-Be structures.
This study tested the load transfer effectiveness of cast-joined structures under flexural loading conditions. Bars of Rexillium III alloy (Ni-Cr-Be) were tested under four-point bending conditions in an Instron testing machine. Six specimens were prepared for each of five interlocking designs. After wax elimination of the investment mold, new metal was cast into the central interlock area. Strain gauges were bonded across the interfaces between the as-cast and secondary cast structures on the bottom surface, and the specimens were loaded to failure in a four-point-bending fixture. Failure was assumed at a strain level of 0.1%, which corresponds to the tensile failure strain of feldspathic porcelain. Three as-cast bars were tested as controls. The average failure load of an interlock design used by Weiss and Munyon was significantly higher (P less than 0.05) than that of the remaining four designs but was significantly lower (P less than 0.05) than that of the solid bar. At the critical strain level of 0.1%, the load-transfer effectiveness of the Weiss and Munyon design was less than 22%. The results suggest that the cast-joining technique may increase the risk of failure in clinical situations where high flexural stresses exist.
DeHoff
P H
PH
University of North Carolina, Charlotte 28223.
Anusavice
K J
KJ
Evans
J
J
Wilson
H R
HR
D003722:Dental Alloys; D003735:Dental Casting Technique; D012994:Dental Soldering; D003799:Dental Stress Analysis; D003779:Denture Design
D003722:Dental Alloys