The press fit condition was analyzed by applying a specific
displacement field to the nodes that lie on the cylindrical hole
surface. The displacement field specifies the overlap existing
between the cylindrical hole surface and the outer surface
of the implant that is geometrically characterized by a specific
analytical procedure. The data definition is provided with
reference to a cylindrical system, where the origin is located
at the center of the bottom surface of the implant, Z is the
implant axis, and r the circumferential and radial directions,
respectively (Fig. 2a). The local implant radius is specified
as a function of the coordinates and Z. With regard to
macro- and micro-threaded regions, the following formulation