Definition:<br />Cast duplication is the process of reproducing a working cast (usually made of stone) to obtain an identical copy without altering the original model.<br /><br />Uses of Cast Duplication:<br /><br />When the original cast needs to be preserved for reference.<br /><br />To fabricate removable partial denture frameworks without damaging the master cast.<br /><br />In implant dentistry, to duplicate diagnostic wax-ups.<br /><br />For teaching, research, or case documentation.<br /><br />Materials Used:<br /><br />Agar hydrocolloid (reversible hydrocolloid) → most common.<br /><br />Silicone duplicating materials.<br /><br />Alginate (less accurate, used for study casts).<br /><br />Procedure (General Steps):<br /><br />Place the master cast in a duplicating flask.<br /><br />Pour in duplicating material (e.g., agar hydrocolloid).<br /><br />Allow it to set, then remove the master cast → leaving a mold.<br /><br />Pour dental stone or refractory material into the mold.<br /><br />Obtain the duplicate cast (identical copy).