Restorative & Materials · single question
A tooth has 0.5mm of remaining coronal structure. PRIMARY concern before placing a crown?
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Correct answer: A. Ferrule height
FERRULE EFFECT: circumferential collar of 1.5-2mm of tooth structure the crown encircles above the finish line — dramatically increases retention and fracture resistance. 0.5mm = insufficient ferrule = crown failure. Crown lengthening or post-core may be needed.
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