If an attachment work is made of non-precious alloys, it is obvious to cast the secondary parts and the cast partial denture together in one piece – the so called one-piece cast. This process saves a lot of time and material. There is no need to cast the secondary crowns separately and to join the double crowns together with the cast partial by soldering, laser welding or adhesive bonding. A further advantage is the biological compatibility due to the usage of only one alloy for all metal parts of the denture. However, you have to get the discrepancy between the single fit of the telescopic crown and the fit in span of the complete prosthetic work under control. That’s a matter of casting expansion and can be regulated by a well aimed use of different investment concentrations. As described in the previous chapter about “bars”, the one-piece cast technique is not limited for the purpose of double crowns.