Intracoronal attachment prosthesis in a patient on denosumab

Correct answer: D. Root canal treatment to retain the tooth

• A. Observation leaves an infected non-vital tooth in place, and periapical infection is itself an MRONJ risk factor. Antibiotics do not treat a necrotic pulp.
• B. Extraction plus immediate implant placement is the highest-risk option available: it combines the extraction with additional osseous surgery in a patient whose bone cannot remodel normally.
• C. Extraction with primary closure reduces MRONJ risk relative to leaving bone exposed, but it is still surgery that a root canal would avoid.
• D. CORRECT. Denosumab is a RANK ligand inhibitor that suppresses osteoclast function and carries a genuine risk of MEDICATION-RELATED OSTEONECROSIS OF THE JAW. Any dentoalveolar surgery raises that risk substantially. The governing principle in antiresorptive patients is to AVOID EXTRACTION where a tooth can be retained, so a non-vital tooth is root-canal treated rather than removed, even where the periodontal prognosis is guarded. Where a tooth is genuinely unrestorable, decoronation with root canal treatment of the retained root is preferred to extraction.

Note: Denosumab differs importantly from bisphosphonates: it is NOT incorporated into bone, so its effect wanes within about six months of the last dose. That makes a planned treatment window in the later part of the dosing interval feasible — a discussion to have with the prescribing physician.

Correct answer: A. Splint it to adjacent teeth

• A. CORRECT. SPLINTING joins a mobile abutment to adjacent teeth so that occlusal load is distributed across a larger combined root surface area and periodontal support. In a patient where extraction is being actively avoided, splinting is the mechanical intervention that keeps a periodontally compromised abutment functional. It is an adjunct to periodontal therapy, not a substitute for it.
• B. Removing the attachment without addressing the tooth abandons both the prosthesis and the abutment.
• C. Fluoride varnish protects the root surface from caries — worthwhile in its own right, but irrelevant to mechanical stabilisation of a mobile abutment.
• D. Increasing occlusal load on a tooth with severe attachment loss accelerates mobility and bone loss. Occlusal forces on a compromised abutment should be REDUCED, by adjustment and by redistributing the prosthesis design.

Correct answer: A. Retention of the removable prosthesis

• A. CORRECT. A precision attachment is fundamentally a RETENTIVE element. It consists of a matrix housed within the abutment crown and a patrix on the partial denture, and the friction or mechanical lock between them resists dislodging forces along the path of insertion — which is precisely the definition of retention.
• B. Bracing against horizontal force is the job of rigid reciprocal components — proximal plates, guiding planes and minor connectors. An attachment contributes some stability but that is not its purpose.
• C. Support, meaning resistance to vertical seating forces, is provided by the rests and by the denture-bearing mucosa, not by the attachment.
• D. Attachments make fabrication considerably MORE demanding, not less. They require precise parallelism, adequate abutment reduction and greater laboratory expertise, and they are costly to maintain.

Correct answer: A. Improved aesthetics through elimination of the visible clasp arm

• A. CORRECT. The retentive mechanism is housed WITHIN the contour of the abutment crown, so there is no metal clasp arm crossing the visible facial surface. In the aesthetic zone this is decisive, and it is the reason attachments are chosen despite everything they cost. A secondary benefit is that the retentive force acts closer to the tooth's long axis, generating less torquing leverage than a clasp arm.
• B. Tooth preparation is GREATER, not less. The abutment must be crowned with enough reduction to house the matrix without leaving thin walls, and this is often the limiting factor in whether an attachment is feasible.
• C. Repair is HARDER. Attachments wear and lose retention over time, components are proprietary and may be discontinued, and replacement can mean remaking the crown.
• D. Attachments are substantially MORE expensive — in the components themselves, the crown work required, and the laboratory time.

Note: Practical prerequisites for an attachment: an abutment with adequate crown height and bulk, a healthy periodontium, and a patient with the dexterity to insert and remove the prosthesis and the means to maintain it. Fail any one and a well-designed clasp is the better prosthesis.