Failing anterior bridge and a collapsed posterior bite

Correct answer: D. Make alginate impressions and mount diagnostic casts

• A. Sectioning is destructive and premature. A bridge loose as a UNIT may have failed at only one abutment; you must first determine which, and whether the abutments are restorable, before committing to removal.
• B. Implants may well feature in the final plan, but a referral made before diagnostic records exist skips the entire treatment-planning step.
• C. Re-cementing without investigation is the classic error. Loosening usually signals recurrent caries, a fractured abutment, or an occlusal overload — cement over the problem and you seal caries under the retainer.
• D. CORRECT. Before anything irreversible, you need DIAGNOSTIC CASTS. Alginate impressions poured and mounted let you assess abutment condition, occlusal scheme, available restorative space, arch form and the shape of the ridge, and they give you a record of the existing prosthesis that cannot be recovered once it is destroyed. They also serve as the basis for a diagnostic wax-up and for provisional fabrication. Diagnosis precedes treatment.

Note: A bridge loose as a whole unit points to failure of the weaker retainer, or to both. A bridge loose on ONE abutment while the other stays cemented is the more dangerous scenario, because caries progresses silently under the loose retainer.

Correct answer: C. Zirconia

• A. A metal-ceramic crown with a metal collar reproduces exactly the problem being solved.
• B. A full gold crown eliminates grey but replaces it with gold — unacceptable in a patient raising an aesthetic complaint.
• C. CORRECT. The grey band is the metal substructure of a metal-ceramic crown showing through thin marginal tissue, made worse as recession exposes the collar. ZIRCONIA is metal-free, so there is no dark substructure and no grey shadow at the margin, and it also avoids the metal-ion gingival discolouration that can accompany base-metal alloys. Modern translucent zirconia gives acceptable aesthetics with strength well above lithium disilicate.
• D. An amalgam core would be visible through any translucent ceramic and can also cause its own greyish tattoo of the adjacent tissue.

Note: The other lever is margin placement. A supragingival or equigingival margin on a metal-free restoration avoids the problem entirely and is far kinder to the periodontium than chasing the aesthetics subgingivally.

Correct answer: A. A vinyl polyether silicone fit-checking material placed in the intaglio

• A. CORRECT. A low-viscosity fit-checking silicone is placed in the INTAGLIO before seating. Where the restoration binds, the film is thin or perforated; where it is not seating, the film is thick. This maps the internal surface directly and identifies the specific interference to relieve. It is the standard method for confirming complete seating of indirect restorations.
• B. Sticky wax is a laboratory adhesive for holding components during soldering or repair. It has no diagnostic role.
• C. Articulating paper marks OCCLUSAL contacts on the outer surface. It says nothing about the internal fit, and occlusal marks on an incompletely seated crown are misleading.
• D. Transillumination detects cracks and caries in tooth structure and is useful for assessing translucency in ceramics, but it does not reveal an internal binding point.

Note: Common causes of incomplete seating: a tight proximal contact, an unrelieved internal line angle, a die spacer deficiency, or a small nodule of ceramic in the intaglio. Check proximal contacts with floss BEFORE blaming the intaglio.

Correct answer: D. Loss of interocclusal restorative space, with a collapsed occlusal plane

• A. Supra-eruption does not increase the vertical dimension of occlusion, which is set by the remaining posterior contacts. What changes is the occlusal PLANE, which becomes irregular.
• B. Supra-erupted teeth do carry caries and periodontal risk from the exposed root surface, but that is a secondary consequence rather than the principal obstacle to rehabilitation.
• C. Clasp retention concerns the abutment on the OPPOSITE side of the arch and is not the governing problem.
• D. CORRECT. A tooth without an opponent erupts, carrying its alveolar bone with it. The consequences are a DISTURBED OCCLUSAL PLANE and, critically, LOSS OF THE INTEROCCLUSAL SPACE needed to restore the opposing arch. There is simply nowhere to put a prosthesis. The options for recovering space are enameloplasty for minor discrepancies, elective endodontics with crown shortening for moderate ones, orthodontic intrusion, segmental osteotomy, or extraction.

Note: Prevention is far easier than correction. Replace or otherwise manage an opposing space promptly — by the time a segment has dropped 3 to 4 mm, recovering space costs endodontics or surgery.