الفهرس 
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Abstract
The fact that. distal extension prosthesis constructed on two supporting mechanisms (the abutment teeth with its periodontium and the edentulous ridge with its masticatory mucosa and underlying bone) and the resiliency of tooth secured by periodontal ligament in an apical direction which is not comparable to greater resiliency and displacement of mucosa covering edentulous ridge as reported by (Stewart et al., 1988). Torque of clasped distal teeth and possible traumatization of residual alveolar ridge is a common sequlae of tissue word movement of distal extension removable partial denture. In attempt to solve the problem of distal extension prosthesis, several authors suggested several methods including distribution of load between teeth and residual ridges which done either by varying connection between clasp and saddle, anterior placement of occlusal rest or mucocompression impression technique. Varying connection between teeth and residual ridges including the use of stress breaking (attachments and flexible connectors), gingivally approaching clasp, occlusal approaching clasp with stress breaking like action, disjunct denture and precision attachments. (Lammie and Laird, 1986). Precision attachments have several disadvantages including devitalization of the abutment, poor appearance due to over contouring the crowns, periodontal damage due to poor gingival contour, considerable chair side time to carry out the procedures and even more laboratory time and costs. Preiskle, (1979) also disjunct denture is technically difficult to construct and patients complaint of rattling during function. (Lammie and Laird, 1986). With all previous approaches; stresses are decreased on abutments, however, the edentulous ridge can accept more vertical and horizontal load and as a result tend to resorb more quickly (Lammie and Laird, 1986). During function; load applied to partial denture may be either vertical, lateral or anteroposterior and any saddle must be designed to resist load on each of these directions (Lammie and Laird, 1986).