What factor primarily affects the retention of a dental crown?

The taper of the preparation is a critical factor that primarily affects the retention of a dental crown. The taper refers to the angulation of the walls of the tooth preparation. A well-designed taper allows for optimal contact and mechanical retention between the crown and the tooth structure, promoting stability once the crown is cemented in place.

When the taper is too steep, the crown can easily dislodge, reducing retention. Conversely, a proper taper provides resistance against dislodging forces, ensuring that the crown remains securely in position during normal functional activities such as chewing.

Other factors, such as the height of the crown, can influence retention to some extent, but taper is considered more influential because it directly impacts how well the crown adheres to the tooth. The material used for the crown does have relevance to strength and aesthetics, but it is not a primary determinant of retention. The color of the crown is purely cosmetic and does not affect how well the crown stays in place.