431 PDS-Adams Clasp

7/27/2019 431 PDS-Adams Clasp

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431 PDS Course Instruments & Exercises

Dr. Abdullah M. Aldrees, Academic Year 2008-2009

The Adams Clasp

Figure 6Figure 5

Figure 4Figure 3

Figure 2Figure 1


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For this exercise you need 10 cm of a 0.7 mm (0.028) stainless steel wire.

1. Mark the mesial and distal undercuts of the model (figure 1).2. Hold the wire just off center and bend down sharply to 90 degrees (figure 2).3. Make a step 2-3 mm in depth keeping the wire flat (figure 3).4. With the beaks of the pliers in the step bend the wire up through the beaks to

form the first arrowhead.

5. Hold the whole of this arrowhead in the beaks and bend to an angle of 45degrees to the bridge (figure 6).

6. Try the clasp on the model by placing the arrowhead on on of the dots. Markthe wire to correspond to the other dot (figure 7).

7. Bend down to 90 degrees at this mark repeating no, 2.8. Make the second step repeating no. 3.9. Make the second arrowhead repeating no. 4.10. Turn this step to 45 degrees (figure 8)11. Try the clasp on the model, The arrowhead must fit the dots (figure 9).12. Hold half the arrowhead in the tips of the pliers and bend down across the beaks

of the pliers. Do not release your hold (figure 10).

13. Still holding the wire, use the index finger to pull the wire to 980 degrees to thebridge (figure 11).

14. Again, try the clasp on the model and adjust until the bridge stands at 45degrees to the long axis of the tooth and the arm is resting on the contact point.

Mark the contact point (figure 12).

15. Bend down over the contact point to bring the occlusal wire in contact with thetooth (figure 13).

16. Wirth the clasp back on the model, mark where the wire leaves the occlusalsurface (figure 14).

17. Bend the wire to the tissue (figure 15).18. Contour the wire to the tissue using soft bends (figure 16).19. Turn the end under to form a tag and try on the model (figure 17).20. Using this completed arm as a guide, hold the base of the second arrowhead in

the tips of the plier and form the second occlusal bend (figure 18).

21. Try on the model and mark the contact point (figure 18).22. Repeat numbers 15, 16, 17, 18, and 19.23. Place the completed clasp on the model (figure 19).


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Figure 3Figure 2

Figure 10Figure 1

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Figure 5Figure 17

Figure 4Figure 15

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Common Reasons of Failure of Adams Clasp

When the buccal bridge is too short ortoo long.

When arrowheads are placed at wrongangle to the buccal bridge.

Work hardening of the wire which maylead to fracture of the wire.

Failure to place the occlusal wire armsin contact over the interproximal area

of the teeth.

When buccal bridge is less or morethan 45 degrees to the long axis of the

tooth.

When there is no means of retentionbetween the tag and the acrylic plate.

References

431 PDS Wire Bending Exercise Manual Part I. Al-Murshid, Z, Hashim, HA, Fones,T. 1994, Riyadh: College of Dentistry, KSU.

The design, construction and use of removable orthodontic appliances Adams, CP,Kerr, WJ. 1990, London: Butterworth-Heinemann Ltd.

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431 PDS-Adams Clasp

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