Adams clasp practice

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epartmentDrthodontic O

DR.Naser Rashed

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Adams clasp

. Adams clasp was first decried by Professor Phillip Adams

It is also known as Liverpool clasp, universal clasp and modified arrowhead

clasp .

The clasp is constructed using 0.7mmhard round stainless steel wire .

Adams clasp is made up of three parts .

(a) Two arrowheads

(b) Bridge

(c) Two retentive arms

Two arrowheads engage the mesial and the distal proximal undercuts .

The arrowheads are connected to each other by a bridge the is at degree to the

long axis of the root .

fig :- Adams clasp

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Steps in fabrication of Adams clasp

1- Plier required for constructing appliances :

Adams pliers, spring forming pliers, mauns cutters

2- A good quality working model cast in stone is required

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4- Mark position of mesial and distal undercuts.

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

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6- Straighten a piece of 0.7mm stainless steel wire.

7- Make a 90 degree bend.

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8- 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.

9- Make another 90 degree bend.

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10- Check length of bridge against model.

11- Forming the arrowhead’s first bend

The length of the arrowhead is determined by crown height of tooth

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12- Forming the arrowhead’s first bend

The length of the arrowhead is determined by crown height of tooth.

13- First arrowhead formed

Both sides of arrowhead should be parallel

First bend into arrowhead should be 90° to bridge.

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14- Forming second arrowhead.

15- Arrowheads are angled to follow tooth contours.

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16- Check angles and arrowheads are parallel.

17- 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

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18- By using the tips of the adams pliers, adjust bend until wire touches

contact point prior to crossing the occlusion.

19- Check position of arrowheads and angulations of bridge

Angle of bridge is 45° to long axis of tooth.

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20- Adaptation of wire across occlusion.

21-Check position and fit.

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

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

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24- Distal tagging should lie forward to allow sufficient space for contour

of acrylic baseplate.

25- Arrowheads must engage undercuts

Bridge should be of sufficient length to allow arrowheads to engage

undercuts

Bridge should be parallel to occlusal plane

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26- Bridge should lie at approximately 45 degrees to long axis of the

tooth.

27- First point of contact out of the arrowhead should be the contact

point prior to crossing the occlusion.

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28- Overview of crib

Bridge follows line of arch