Gold Solders for Dental Use

Soldering in Prosthodontics-An Overview, Part I

“…. 25 The melting range can be narrowed by lowering the Au content and raising the Cu content; Zn and Sn lower the melting point. Au imparts corrosion resistance, and although the exact minimal Au percentage necessary has not been conclusively established, it is probably of the order of 58% to 61% (0.580/0.615F) 6,7 .…”

“…It means that the solder was formulated for use with a particular karat casting alloy (e.g., 18K casting gold); it does not refer to the Au content of the solder. Fineness refers to parts per thousand of Au in a solder (e.g., 0.650F), and has been recommended as the more desirable designation 25 . Unfortunately, fineness designation ignores other noble elements such as Pt and Pd.…”

“…Unfortunately, fineness designation ignores other noble elements such as Pt and Pd. In 1949, Taylor and Teamer 25 stated that “in selecting solder, the physical advantages (strength/flow) accruing through the use of lower karat solders in many cases outweigh the possible greater corrosion resistance of high karat alloys.” Two authors 26,27 have recently recommended lower fineness solders due to strength and handling characteristics.…”

“…Certain properties of dental solders are considered important 8,9 . The commonly cited list (for conventional gold solders) seems to originate with Taylor and Teamer 25 …”

“…O’Brien et al 28 showed that 0.437 fine solder exhibited greater wetting properties than 0.650 fine solder, and that a Pb–Sn solder exhibited perfect wetting. Strength similar to that of the parent alloy 8 Solders are modified versions of parent alloys and as such are weaker. Fortunately, joint strength is enhanced by heat hardening, and the phenomenon known as triaxiality. Freedom from pitting Pitting is largely a consequence of poor heating and fluxing technique due to operator error 25 . However, pits may be more prevalent when the solder contains a considerable amount of low‐fusing elements such as Zn and Sn.…”