Attachment-Retained Partial Denture

Correct answer: A. Retention of the removable partial denture

• A. Correct. In a removable partial denture, the precision attachment functions as the direct retainer. Its matrix is housed within the abutment crown and its patrix is incorporated into the framework, so retention is generated internally rather than by a clasp arm engaging an external undercut.
• B. Incorrect. Providing a vertical stop and directing force along the long axis of the abutment is the function of the occlusal rest.
• C. Incorrect. Cross-arch stabilization is the function of the major connector, which distributes force across the arch and resists rotational displacement.
• D. Incorrect. Transferring load to the residual ridge is the function of the denture base and its extension. The attachment does the opposite — it directs load toward the abutment.

Note: Distinguish carefully between contexts. In a fixed partial denture with a pier abutment, a non-rigid connector serves to relieve stress and prevent torquing of the pier. In a removable partial denture, an intracoronal attachment serves as a retainer. Same phrase, different purpose.

Correct answer: C. Improved esthetics — no visible clasp arm on the buccal surface

• A. Incorrect. Preparation is more demanding. The abutment must be prepared with enough depth to house the matrix without encroaching on the pulp, which frequently requires endodontic treatment and a full-coverage restoration.
• B. Incorrect. Repair is more difficult, not less. A fractured attachment component often requires remaking the crown or replacing proprietary parts.
• C. Correct. Retention is generated inside the crown contour, so no metal component crosses the visible buccal surface. This is the reason the technique is chosen and it directly addresses her chief complaint.
• D. Incorrect. Precision attachments are considerably more expensive, requiring specialized components and precise laboratory work.

Correct answer: A. Place the occlusal rest in the mesial fossa rather than the distal fossa

• A. Correct. A mesial rest shifts the fulcrum line away from the distal extension. When the base is loaded, the framework rotates about the mesial rest and the retentive arm moves into a non-retentive area rather than being levered against the abutment. This is the core stress-releasing principle behind the RPI and RPA systems.
• B. Incorrect. A distal rest places the fulcrum immediately adjacent to the extension base, so functional loading levers the abutment distally — exactly the destructive torque to be avoided in a periodontally involved tooth.
• C. Incorrect. A rigid connection transmits the full displacement of the extension base directly to the abutment, maximizing rather than minimizing torque.
• D. Incorrect. Removing the rest allows the framework to settle into the gingival tissues, causing soft tissue trauma and losing all vertical support and load direction.

Note: The RPI system — mesial Rest, distal Proximal plate, I-bar — is designed specifically for distal extension cases. On rotation, all three components disengage from the abutment rather than binding against it.

Correct answer: C. A non-rigid connector

• A. Incorrect. A retained root tip is a discrete fragment of root with a periodontal ligament space and lamina dura, located within bone.
• B. Incorrect. A cast post and core is a tapered radiopaque structure occupying the canal space within a root, not an interface between two prosthetic units.
• C. Correct. A non-rigid connector appears radiographically as a distinct rectangular keyway in one retainer with a matching key on the adjoining unit, producing a visible interface line within an otherwise continuous prosthesis.
• D. Incorrect. An implant abutment screw is a threaded component within the implant body, showing the characteristic screw thread pattern along its length.