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
tooth
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.