terminate adjacent ring 22 these pins 18 hold the resulting pattern in an investment material 26 while casting is being done once the pattern is in place within ring 22 an investment material 26 is placed in ring 22 in a conventional manner so that the wax is lost and the investment material 26 forms a mold for the casting pins 18 are embedded in material 26 so as to hold core 12 in place during casting the casting operation can now be carried out in a conventional manner and when finished the resulting casting removed from ring 22 together with material 26 and cleaned the pins 18 cut off and the resulting subframe finished to receive the porcelain and the like the latter is placed on the stone model so as to form the covering layer 16 and finish off the pontic 10 pins 18 extend from the wax pattern approximately 3 8 34 for example to be held in position by the investment material 26 while the molten metal which will form the casting is being introduced into the mold left by wax after the latter has been removed in the conventional manner during the investment a minimum of 3 4 of a millimeter of wax should be placed around core 12 when forming the pontic with the result that the metal mass 14 will be at least 3 4 of a millimeter thick when grinding core 12 for occlusal clearance one should be sure to keep the wax away from the area to be ground further the residue of any wax affected by the grinding should be cleaned completely from the surface of core 12 or from the.