Studies on the influences of the indirect retainers on the displacements of the denture bases and the abutment teeth. Part I. Their forms and presence or absence

In the removable partial denture, it is very important that the denture movements are reduced and that the occlusal forces are distributed appropriately to the abutment teeth and the residual ridges. The purpose of this experimental studies are to investigate and evaluate characteristic movements of the denture bases and the abutment teeth, when the indirect retainers are altered.The results are as follows:(1) In the unilateral mandibular dentures, most of the occlusal forces are transmitted in the lingual direction.(2) Both the amount of the denture movements and the harmful displacements of the primary abutment tooth are remarkably minimized, when the dentures have the indirect retainers with the positive rests, the minor connectors fitted with the subguide planes and the cross-arch stabilizations.(3) In the case of the oblique forces to the dentures, the displacements of the denture bases and the abutment teeth are reduced when there are the cross-arch stabilizations and the indirect retainer with the positive rest in their denture frameworks.