Final Impression With Subgingival Margin and Bleeding
A 61-year-old patient is scheduled for a PFM crown on tooth #19. The buccal margin is 0.5 mm subgingival, and the gingiva bleeds easily during probing. The patient takes aspirin 81 mg daily and reports no other anticoagulants. The first final impression showed voids at the buccal margin. You have retraction cords in sizes 000, 00, 0, and 1, aluminum chloride and ferric sulfate hemostatic agents, retraction paste, and a stock metal tray with a medium-body VPS. The dentist prefers a single-cord technique unless the sulcus will not open. The patient's blood pressure is 128/78, and there is no history of cardiac arrhythmia.
1. Select a retraction cord size and medicament, and describe the sequence you would use to obtain a dry, open sulcus without unnecessarily traumatizing the tissue. Justify the single- versus double-cord decision.
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I would start with a 00 aluminum chloride cord because the sulcus is shallow and the tissue is inflamed; a larger cord or ferric sulfate could traumatize tissue and stain. I would place the cord gently with a blunt instrument, pack it below the buccal margin, and leave it 5–10 minutes. Aspirin 81 mg is not a reason to avoid retraction, but I would monitor bleeding. If the sulcus does not open, I would add a second, smaller cord (000) or use retraction paste rather than forcing a larger cord. I would avoid epinephrine-impregnated cord because it is unnecessary here and aluminum chloride gives local hemostasis without systemic effects. The single-cord technique is preferred unless the sulcus will not open, because double-cord packing increases the risk of tissue trauma and retained cord fragments.
2. If the margin still bleeds after retraction, what would you do next, and how would you verify the margin is captured before the impression is sent to the laboratory?
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If bleeding persists, I would remove the cord, place retraction paste or a fresh aluminum chloride cord for another 3–5 minutes, and use gentle suction. I would not proceed with a bloody field. For the impression, I would syringe light-body VPS around the margin first, then seat the tray with medium-body material. After removal, I would inspect the buccal margin under magnification and look for tears or voids; if any are present, I would repeat the impression rather than pour a defective one. I would also verify that no cord fragment remains in the sulcus. The reasoning is that a void at a subgingival margin cannot be corrected by the laboratory and will produce an inaccurate crown.