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Construction of an Adams Clasp

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This demonstration shows the laboratory construction of the Adams Crib. It is presented by Edwin Payne and Kerry Lancaster of Eastman Dental Institute.


Peer reviewed by Dr S.Jones Consultant Orthodontist/Honorary Senior Lecturer Eastman Dental Hospital and Institute for Oral Health Care Sciences.


Mark position of mesial and distal undercuts.

Prepare undercuts
These should be prepared to approx. 1mm in depth
Avoid trimming the buccal surface of tooth.

Straighten a piece of 0.7mm stainless steel wire.

Make a 90 degree bend.

Mark the length of the bridge onto the wire
This should be the distance between the two marks on the model where the arrowheads will engage the undercuts.

Make another 90 degree bend.

Check length of bridge against model.

Forming the arrowhead’s first bend
The length of the arrowhead is determined by crown height of tooth
Forming the arrowhead’s first bend
The length of the arrowhead is determined by crown height of tooth.
First arrowhead formed
Both sides of arrowhead should be parallel
First bend into arrowhead should be 90° to bridge.

Forming second arrowhead.

Arrowheads are angled to follow tooth contours.

Check angles and arrowheads are parallel.

Second bend from the arrowhead
This bend should be below the height of the bridge
This is achieved by clasping the arrowhead halfway up the outer side, prior to bending

By using the tips of the adams pliers, adjust bend until wire touches contact point prior to crossing the occlusion.

Check position of arrowheads and angulations of bridge
Angle of bridge is 45° to long axis of tooth.

Adaptation of wire across occlusion.

Check position and fit.

Bring wire 2/3 into palate to form tag end.

Uniform spacing of 1mm with a foot at the end of tag.

Distal tagging should lie forward to allow sufficient space for contour of acrylic baseplate.

Arrowheads must engage undercuts
Bridge should be of sufficient length to allow arrowheads to engage undercuts
Bridge should be parallel to occlusal plane

Bridge should lie at approximately 45 degrees to long axis of the tooth.

First point of contact out of the arrowhead should be the contact point prior to crossing the occlusion.

<< Overview of crib
<< Bridge follows line of arch