Dental crown securement system involves spreading base passage to expand and lock screw until activated by inserted hollow screw for removal etc.

摘要

The base (5) passage (6) contains a spreader sleeve (7) having lengthways slits (14) for the end facing the screw (4). The sleeve (7) expands in response to an expander element, here in the form of a grubscrew (8) operated by a hollow screw (9). Grooves (10) on the spreader (7) are engaged by holder (12) projections (11) as accessed (13) by the screw (9).