R_Bibb_Medical_Modelling_The_Application_of_Adv.pdf

6.77a The physically surveyed cast.
Case studies 223
6.77b The digitally surveyed, ‘buck’ cast – undercuts are shown as
dark areas.
undercuts were marked with a line for use in the design stages. RPDs
provide fi rm location on the existing dentition by using fl exible clasps. The
clasp components of the RPD open on initial contact during insertion and
removal, and return to their original position within the undercut on fi nal
seating, thus providing secure retention.