An in vitro study evaluated the retention of metal copings prepared with five different tapers and luted with two different cements. Eighty extracted human maxillary premolar teeth with measured dimensions & sound surfaces were selected for the study.crown preparations were done using a high speed hand piece which was stabilized by a specially fabricated customized holding device that can be moved in horizontal plane to obtain the desired degree of taper for the preparation. The crown preparation with different tapers 0, 3, 6, 9& 12 degrees respectively were achieved. Die Preparation, wax...