Most common reason for a crown not to fully seat upon delivery

# What is the most common reason for a crown not to fully seat upon delivery?
A. Excessive proximal contacts
B. Over extended margins
C. Undercuts on the axial surfaces of the prepared
D. Positives on the intaglio surface

The correct answer is A. Excessive proximal contacts. 

Excessive proximal contacts are sometimes accidentally made by dental technicians effort to prevent open contacts on their fabricated dental crown/ bridge.

The respective tooth preparations on the
die casts are sawed to separate each component and provide better visualization
of the prep. Dental technicians may accidentally scrape a portion of the contact
area of the adjacent teeth causing a future
excessive contact in the final crown restoration.

Excessive contacts can also be created
when wax patterns are not immediately
invested, causing dimensional changes in
the final restoration.

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