Key with Movable Bolster (6 slides)
Having a movable bolster reduced gum trauma throughout the extraction process by applying a more uniform pressure to the fulcrum as the shaft rotated.
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Movable Bolster Key IllustrationThis innovative design first appeared in 1796 and was described in 1845 as "one of the most valuable improvements which this instrument has ever undergone."
Courtesy of Martino Publishing, Eastford, CT — Colyer, 2006
Enhanced KeyA circa-1800 key (A256.6) shows a number of new features, including...
University of the Pacific Permanent Collection, Donor: Herbert J. Stuart, DDS (’37)
Knurled ThumbscrewA circa-1800 key (A256.6) shows a number of new features, including a hardwood handle with knurled thumbscrew.
Bolster Designed for CoveringA soft covering can be sewn to the thin movable bolster through its four holes.
Spring-Loaded PinRunning inside the lower shaft, a spring-loaded pin allows quick reversal of the same claw, for left verses right extractions, or exchange of different-sized claws.
Slender ClawThe slender claw has a well-worn tip.