1

epartmentDrthodontic O

DR.Naser Rashed

2

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

3

4

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

5

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.

6

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

7- Make a 90 degree bend.

7

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.

8

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

9

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.

10

14- Forming second arrowhead.

15- Arrowheads are angled to follow tooth contours.

11

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

12

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.

13

20- Adaptation of wire across occlusion.

21-Check position and fit.

14

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

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

15

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

16

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.

17

28- Overview of crib

Bridge follows line of arch