b) After the stone has set, remove the denture from the cast, and, with an arbor band or denture bur, cut away the denture base material to widen the fracture line to one-eight of an inch. The edges to be joined should be rabbetted to increase the surfaces for the attachment of the new material and to form channels in which to confine the acrylic dough during the packing and processing procedures. The groove on both sides of the fracture should be one-fourth of a thickness of the base material. Dovetails than are cut into the base material on both sides of the fracture line to gain physical as well as chemical union. If there are any undercuts, it may be impossible to remove the denture from the cast to prepare the fracture lines. In this case, the fracture lines should be widened through to the cast and the edges must be prepared with out removing the denture form the cast.