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The
Ackermann Clip
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| A bar clip attachment that
allows free movement of the prosthesis. Its applications are for
overdentures and implant prosthetics. The principle feature of the
Ackermann Clip is that the bar may be adjusted to follow not only the
vertical contours of the mucosa, but also the anterior-posterior curvature
of the edentulous ridge. The spacer provides for both vertical
and rotational free movement of the prosthesis. The clip is fully
adjustable and easy to insert and remove. |
| Wide field of applications, as the bar
may be bent in all directions allowing it to exactly follow the contours of
the ridge (FIG 1). |
1 |
| The Ackerman may be used for
square or curved arches.
Due to its short 3.6mm length, the sleeve may be
positioned on the bar even in a deep narrow trough (FIG
1). |
2 |
3 |
| No soldering of the clip.
The horizontal retention tangs (FIG 2-3)
provide firm retention in acrylic and require no additional vertical space.
Firm yet resilient support of the prosthesis assured by
the elasticity of the riders. Spacer provides for free vertical
movement.
Easy path of insertion and removal.
The ackermann clip fits the Round Bar, the Hader Bar,
and the small Dolder Bar. The shape of the bar is indicated by the
amount of room available, by the shape of the alveolar ridge, and the type
of construction.
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Technique |
| 1. Prepare the
abutment teeth in a normal manner. The bar can be soldered, cast, or
laser welded to fit abutment crowns, root cap copings, or implant abutments. |
| 2. Try in all cast restorations. |
4
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| 3. Try-in set-up. |
| 4. Make a plaster matrix of set-up. |
| 5. Ensure that there is sufficient
clearance between the bar and the mucosa so that the extensions of the clips
can move freely without impinging on the alveolar tissue (FIG
4). |
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5 |
6 |
| 6. Wax out the
undercut area beneath the bar on the model and relieve the areas where the
retention sleeves will be placed (FIG 5).
7. Duplicate and cast model. Place the
clips in the desired position on the model after having cut away the plaster
very slightly in these positions to avoid opening up the clips too much (FIG
6).
The sleeve is then raised to its highest position and
held there by the insertion of a piece of the special half-round spacer (FIG
7a-b). |
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7a |
7b |
| 8. Place the
clips in position. Block out their ends as show in (FIG
8a-b). With the aid of the plaster matrix, set up teeth and
process on the model. |
|
8a |
8b |
| The ackermann clips firmly retained in
the prosthesis (FIG 9). |
9 |
| 9. After periods of use, it may be
necessary to further activate the sleeves by pressing them inwards with an
instrument (FIG 10). |
10 |
