Denosumab, Kennedy Class I RPD with a precision attachment on #21

Correct answer: D. Pulp necrosis with symptomatic apical periodontitis

• A. A chronic apical abscess is defined by intermittent drainage through a sinus tract and is typically ASYMPTOMATIC — the opposite of the percussion sensitivity described.
• B. Reversible pulpitis also requires a vital, responsive pulp with pain that resolves promptly.
• C. Irreversible pulpitis requires a VITAL pulp that responds to cold with lingering pain; this tooth does not respond at all.
• D. Correct. A NEGATIVE cold test means the pulp is NON-VITAL — necrosis. Sensitivity to PERCUSSION localises inflammation to the periodontal ligament, giving SYMPTOMATIC apical periodontitis as the periapical diagnosis.

Correct answer: B. Root canal treatment through the existing restoration

• A. Implant placement in a patient on DENOSUMAB (an antiresorptive with MRONJ risk comparable to bisphosphonates) is a further reason to avoid surgery here.
• B. Correct. The abutment carries the precision attachment for a Kennedy Class I RPD. Extracting it would convert the case and force a remake of the prosthesis. Endodontic treatment through an access in the existing crown preserves the abutment and the attachment, and is the conservative choice when the tooth is otherwise retainable.
• C. Extraction sacrifices the abutment and the attachment system, which is precisely what the question asks you to avoid.
• D. Periodontal surgery does not address a necrotic pulp.

Note: Denosumab is a RANK-ligand inhibitor — not a bisphosphonate, but it carries a comparable MRONJ risk. Unlike bisphosphonates it does not incorporate into bone, so its effect wanes roughly 6 months after the last dose, which affects the timing of any elective surgery.

Correct answer: A. Splint #21 to #22

• A. Correct per the source key. SPLINTING the terminal abutment to the adjacent tooth distributes the torquing load generated by the distal-extension base across two roots, increasing the effective root surface area and reducing the leverage applied to any single abutment.
• B. Substituting a clasp does not by itself resolve the load concentration on a lone terminal abutment.
• C. Rest position and design matter greatly in distal-extension cases, but simply adding a distal rest on the terminal abutment increases rather than reduces the tipping force — which is why mesial rests are favoured in Class I and II designs.
• D. Relining is essential maintenance in distal-extension RPDs and does reduce tissue-ward settling — but the question asks about preventing abutment resorption, for which splinting is the keyed answer.

Correct answer: A. Retention

• A. Correct. A precision (intracoronal) attachment is a direct retainer — its primary function is RETENTION, resisting vertical dislodgement of the prosthesis away from the tissues.
• B. Support is resistance to VERTICAL displacement TOWARD the tissues, provided by rests on abutments and by the denture-bearing mucosa and bone.
• C. Resistance is a preparation-geometry term from fixed prosthodontics (resistance form), not a function of an attachment.
• D. Stability is resistance to HORIZONTAL/lateral displacement, provided mainly by rigid major connectors, guide planes and bracing arms.

Note: This same question appeared on Day 1 — it is clearly a favourite. Retention = away from tissue; Support = toward tissue; Stability = lateral.

Correct answer: B. Esthetics — no visible metal clasp arm on the abutment

• A. Precision attachments are considerably MORE expensive, requiring crowns on the abutments and precise laboratory work.
• B. Correct. The chief advantage of an intracoronal precision attachment is ESTHETIC — the retentive element is hidden within the contour of the abutment crown, eliminating the display of metal that a clasp arm produces on an anterior or premolar abutment.
• C. Load distribution is arguably worse in distal-extension cases: the rigid attachment transmits torquing forces directly to the abutment, which is the mechanism behind this very case.
• D. Maintenance is more demanding, not simpler — the male/female components wear and require periodic replacement or activation.

Correct answer: C. The distal torquing force generated by the attachment to the distal-extension RPD

• A. Caries would produce a restorative problem but does not explain a torquing pattern of bone loss with a rigid attachment on a distal-extension case.
• B. Denosumab REDUCES bone resorption — it is an antiresorptive. It cannot be the cause of localised bone loss around one abutment.
• C. Correct. In a Kennedy Class I (distal-extension) case the base is supported partly by resilient mucosa and partly by the rigid abutment. As the base settles into the tissue under load, the RIGID attachment transmits a distal TORQUING/tipping force to the terminal abutment. Repeated over time this produces the classic picture: increasing mobility and vertical bone loss on the abutment.
• D. The tooth's endodontic status is a consequence in this case, not the cause of the periodontal breakdown.

Note: This is why stress-breaking designs, mesial rests, physiologic (altered cast) impressions and regular relining exist in distal-extension partial denture design.