Prosthodontics & Occlusion · patient case question
The grey marginal discoloration around the existing crown on tooth #6 in this bruxist patient is most likely caused by:
Patient case: Ceramic Crown Delivery
demo: 38-year-old male
chief: Delivery of a lithium disilicate crown on tooth #30.
history: Bruxism. Existing crown on #6 has become discolored at the margin.
meds: None
findings: Lithium disilicate crown returned from the laboratory. Adjacent tooth #6 shows a grey marginal discoloration beneath a ceramo-metal crown.
Show answer and explanation
Correct answer: C. Exposure of the underlying metal or dentin at the margin from wear and recession
- A. Tetracycline staining is generalized and banded through the whole tooth, present from development — it does not appear as a new marginal line.
- B. Fluorosis produces white opaque or mottled brown enamel, developmentally, not a marginal grey line.
- C. Correct. Parafunction plus gingival recession exposes the metal collar of a ceramo-metal crown or the darker underlying dentin, producing a grey line at the margin.
- D. An amalgam tattoo is a blue-grey macule in the soft tissue, not a discoloration of the crown margin.
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