SOLDERING TECHNIQUES ARE OFTEN USED TO AVOID DIFFICULTIES WHICH ARISE IN ACCURATELY CASTING LARGE-SPAN DENTAL BRIDGES.

SOLDERING TECHNIQUES ARE OFTEN USED TO AVOID DIFFICULTIES WHICH ARISE IN ACCURATELY CASTING LARGE-SPAN DENTAL BRIDGES. TO AVOID THIS PROBLEM, SUBUNITS ARE CAST AND ASSEMBLED BY SOLDERING. A DETAILED UNDERSTANDING OF THE ALLOY/SOLDER INTERFACE DOES NOT EXIST. THERE ARE CONFLICTING REPORTS ON ALLOY/SOLDER EPITAXY AND ON THE FORMATION OF INTERFACIAL PHASES. THIS STUDY WILL CORRELATE THE MECHANICAL PROPERTIES OF SEVERAL DENTAL ALLOY/SOLDER INTERFACES WITH THE MICROSTRUCTURES OBSERVED BY CROSS-SECTIONAL TRANSMISSION ELECTRON MICROSCOPY (XTEM). FIVE ALLOYS WITH VARYING AMOUNTS OF AU AND PD WILL BE JOINED USING SIMULATED PRECERAMIC AND POSTCERAMIC SOLDERING TECHNIQUES. THE ALLOY/SOLDER STRENGTH WILL BE MEASURED USING THREE-POINT FLEXURAL BENDING. THE MICROSTRUCTURE WILL BE EXAMINED USING XTEM. THE RESULTS OF THIS STUDY SHOULD PROVIDE A SOLID EXPERIMENTAL BASIS FOR THE NATURE OF THE ALLOY/SOLDER INTERFACE AND ENABLE MATERIALS SCIENTISTS TO TAILOR ALLOY/SOLDER COMBINATIONS TO OPTIMIZE THEIR IMPORTANT PARAMETERS. PHASE II OF THIS PROGRAM WILL APPLY THE PRINCIPLES LEARNED IN PHASE I TO THE DEVELOPMENT OF NEW ALLOY/SOLDER COMBINATIONS. IN ADDITION, THE TECHNIQUES DEVELOPED UNDER PHASE I WILL BE EXTENDED TO OTHER DENTAL