著者

荒川 仁志 鷹股 哲也 田村 利政

出版者

松本歯科大学学会

雑誌

松本歯学 (ISSN:03851613)

巻号頁・発行日

vol.19, no.1, pp.54-61, 1993-04-30

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The reasons for difficulties involving the distal extension removable partial detures is their undue movement under the occlusal forces. The supporting structures in removable partial dentures (abutment teeth and residual ridges) are "living things" and are subjected to forces. To a great extent the forces accruing through a removable restoration can be widely distributed, directed, and minimized by the selection, design, and location of components of the removable partial denture and by developing a harmonious occlusion. For these reasons, mesial rest I bar clasp (RPI) is the most commonly used retainers for distal extension removable partial dentures. The RPI clasp allows release from an abutment tooth when occlusal forces are applied to the denture base, and the clasp gives good resistance to occlusal displacement, covers a minimun of tooth structure, and in most situations shows less metal than other clasps. However, when an insufficient vestibular depth will not allow the I bar to be released from tissue, undercut below the abutment teeth for the I bar may be so extensive that it is uncomfortable for the patient. In these situations, the RPI clasp cannot be used. This paper presents the clinical considerations about the RPA clasp serving as the RPI clasp.