Prosthodontics & Occlusion · patient case question
When trying in the final ceramic crown, which is the best way to confirm it is FULLY SEATED?
Patient case: Failing anterior bridge and a collapsed posterior bite
Patient: Female, 68 years old
Chief complaint: “My front bridge is loose, and my temporary cap fell off while I was eating.”
History: Hyperlipidaemia, depression. Medications: atorvastatin, citalopram.
Findings: Anterior fixed partial denture is mobile as a unit. An existing metal-ceramic crown on tooth #14 shows a grey band at the gingival margin. Diagnostic casts show the mandibular left posterior segment supra-erupted into the opposing edentulous space. A new all-ceramic crown is being tried in on tooth #30.
Show answer and explanation
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.
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