Also called as Liverpool clasp, universal clasp and modified arrowhead clasp.
Clasp constructed using 0.7 mm hard round stainless steel wire.
Parts of Adam’s clasp
Two arrow heads
Bridge
Two retentive arms
The undercuts are marked on the model
as shown using a pencil.
The undercuts are then prepared to a
depth of 1mm, using an Ash 9 or similar if
necessary. This image clearly shows
the undercuts have not been enhanced
on the molar tooth because the tooth is
fully erupted. Only partly erupted teeth
should have the undercuts enhanced,
as discussed by Adams 1953. The
technician should use his or her own
judgement when assessing teeth to be
clasped and the need to enhance
undercuts or not.
N.B. Trimming of the buccal surfaces of
the molar tooth should be avoided.
Adams pliers and 0.7mm S.S wire are
used to fabricate the Adams clasp
The 0.7mm S.S wire is straightened. (Pre
cut 0.7mm S.S wire can also be
purchased).
Firstly, the 'bridge' part of the Adams clasp
is formed - A 90 degree bend is made midway along the 0.7mm S.S wire.
At this point the length of the bridge is
marked as shown. Remembering that the
overall length should be between the two
pencil marks on the model as this is the
position the arrowheads will engage.
The second 90 degree bend is made in the
0.7mm S.S wire.
The bridge length is checked against the
model.
Using the beaks of the Adams pliers, a
smooth arrowhead can be formed. N.B.
The length of the arrowhead is determined
by the height of the tooth. A 'tall' / 'long'
tooth for example from tip of cusp to
gingival margin would require a longer
arrowhead.
The completed first arrowhead. N.B. Both
sides of the arrowhead should be 900
degrees to the bridge.
The second arrowhead is formed in the
same way.
The arrowheads are formed to follow the tooth's contours (commonly approx 45
degrees). The arrowheads should be parallel.
The second 90 degree bend from the
arrowhead is then performed by holding
the arrowhead in the beaks of the Adams
pliers approximately half way along its
length as shown.
The outer arm of the arrowhead should be
below the height of the bridge. (Certainly
no higher).
The outer arm of the arrowhead is adjusted until the wire contacts the embrasure point
prior to the interstitial area (crossing the occlusion) of the occlusion. N.B. The angle of
the bridge should be at 45 degrees to the long axis of the molar tooth.
The outer arm of the first arrowhead is then formed over the interstitial area of the molar
tooth and the tag formed approximately two thirds into the palate. N.B. The distal tag
arm should be positioned forwards to allow for contouring of the acrylic base plate.
This image shows the ideal spacing of
1mm between palate and 0.7mm S.S wire.
The anterior tag arm is formed over the interstitial area and into the palate in the same
way. N.B. The bridge is parallel to the occlusal plane. Also the outer arms of both
arrowheads are formed slightly away from the molar tooth to allow space for adjustment
of the Adams clasp in the clinic if necessary as shown. Therefore, the first contact point
exiting the arrowhead should be the embrasure prior to the interstitial area (crossing the
occlusion).
The bridge should be long enough to allow
the arrowheads to engage the undercuts.
The bridge should be at approximately 45 degrees to the log axis of the tooth.
Ref: - Isaacson, Muir, Reed - Removable Orthodontic Appliances 2002. ISBN 0723610533.
Advantages
It is rigid and offers excellent retention
It is fabricated on deciduous as well as permanent teeth.
They can be used on partially or fully erupted teeth.
It can be used on molars , premolars and on incisors.
No specialized instrument is needed to fabricate the clasp.
It is small and occupies minimum space.
The can be modified in a number of ways like Adam’s with single arrowhead.
Adam’s with J Hook.
Adam’a with incorporated helix.
Adam’a with additional arrowhead.
Adam’s with soldered bucca tube.
Adam’a with distal extension.
Adam’a n incisors and premolars