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The
Original
OSO
O-Ring System |
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OSO Components
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Castable Male overdenture pattern.
- 5.2mm height, may be reduced to 2.5mm
- 2.0mm Ø
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FDA Approved Processing O-Ring
- 1.3mm height
- 4.2mm outer Ø
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Metal Housing for O-Rings
- 2.0mm height
- 5.2mm outer Ø
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OSO
Overdenture Fabricating Jig
One per package.
For duplication and retention in stone models.
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Benefits:
- Economical and easy to use
- May be used with post copings, cast copings, or bar
constructions
Instructions
Attachment technique for
Overdentures
1. Conventional preparations are made for root cap
post copings.
2. Full arch impressions are taken so that the male
posts may be paralleled in the wax up.
3. Models and dies are prepared and copings waxed.
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1 |
4. Plastic male posts are shortened
to the desired length from the gingival.
The hemispherical head of the
male post should be maintained to provide the torque-free ball and socket
action between the denture and the attachment. The head may be
shortened but the effectiveness of the stress relieving action will be
reduced (FIG 1). |
5. Lute the plastic male posts to the waxed copings
using the paralleling mandrel to parallel multiple attachments and to establish the best
path of insertion in relation to the configuration of the ridge and tissue
undercuts.
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2 |
3 |
4 |
| 6. Sprue and cast the
male plastic patterns.
An auxiliary sprue may be carefully placed to the end of the male post to
assure a complete casting of some alloys. Finish and fit copings
to the master model. Remove any imperfections from the attachments.
Rubber wheel and polish the junction of the O-Ring groove and the hemispherical head to
a slightly smaller diameter than the body of the post (FIG 2).
Cut the pressure relief groove (The head must be reduced in this manner
because it is slightly larger than the body of the post to allow for this
reduction). With a disc, cut the pressure relief groove in the head of
the male post from the O-Ring groove to the topmost point of the
hemispherical surface (FIG 3 & 4). This will prevent
compression of air and fluids in the chamber beyond the O-Ring as the
prosthesis is being seated.
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5 * |
7. Cover copings and attachments
with O-Rings in place with plaster, stone, or silicone putty (FIG 5).
Set-up, try-in and finish in a normal way. 8.
The dentist seats the denture. The space created by the stone or
plaster over the copings during processing will allow the denture to seat
without contacting the copings or the attachments. |
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6 |
9. The dentist allows the patient
to wear the denture for several days until the denture is well seated and
most adjustments have been made and the patient is comfortable.
10. The dentist drills a hole from the lingual of
the denture through to the void area around the attachment (FIG 6).
11. The dentist decides whether the denture is
to be immediately root supported or tissue resilient and to what degree. |
For root supported
overdentures
The surgical stainless steel retainer ring for the OSO
attachment aids in the seating and replacement of the rubber O-Ring and helps to
preserve the acrylic around the opening. The Retainer Ring can be placed
flush with the gingival of the denture, thereby reducing the height necessary
for the male post, if so desired.
After casting or after cementing the Male Post, seat the
red processing Ring into the Retainer Ring and put in place on the male
attachment. Block out the gingival portion of the Retainer Ring down to
the coping or base. The balance of the processing is as usual.
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6 |
12. Use the red O-Ring for
processing. Place the red processing O-Ring on to the male post into
the O-Ring groove. Fill the pressure relief groove in the head of the
male post with soft wax. Place self curing acrylic into the
void from the tissue side and seat the denture carefully, holding firmly in
the rest position without undue pressure until acrylic is set. A
piece of rubber dam should be cut to size, a hole punched and placed over the male
post to cover the surface of the coping and adjoining tissue. This
will protect the tissue and provide a little freeway space between the
denture base and the coping.
The hole drilled in the lingual will
allow the excess acrylic to escape, or it can be used for adding more
acrylic after the denture has been seated (FIG 6). |
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7 |
13. After processing remove the
O-Ring from the denture and with a sharp bur of the right size enlarge the
chamber very slightly, just gingival to the O-Ring groove (see top
arrow). If rubber
dam was not used to create freeway space between the denture base and
coping (see lower arrow), then the area of the denture contacting the coping should be
relieved with a bur only on the part lingual of the male post. This
will provide freeway space for the ball and socket action of the denture on
the hemispherical head of the male post under posterior occlusal load and
prevent torquing of the abutments.
The part of the coping
labial to the male post will remain in contact with the denture and help to
resist unseating forces in the posterior area, much like an indirect
stabilizer (FIG 7). |
For Tissue Supported
Overdentures
The surgical stainless steel retainer ring for the OSO
attachment aids in the seating and replacement of the rubber O-Ring and helps to
preserve the acrylic around the opening. The Retainer Ring can be placed
flush with the gingival of the denture, thereby reducing the height necessary
for the male post, if so desired.
After casting or after cementing the Male Post, seat the
red processing Ring into the Retainer Ring and put in place on the male
attachment. Block out the gingival portion of the Retainer Ring down to
the coping or base. The balance of the processing is as usual.
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8 |
14. Follow the same procedures as
above, except place sticky wax on the head of the male post of the
desired thickness. The sticky wax will adhere better than other wax.
The thickness of the wax applied will determine how far the denture will
move tissueward under load before it will contact the head of the male post
and become abutment supported.
When the denture base does come in
contact with the male post, the abutment will start supporting the denture,
but will allow the ball and socket rotation under posterior occlusal load to
prevent or reduce torquing of the abutments (FIG 8).
Notice the free space for rotation and support, as shown
by the arrows. |
The freeway space may be provided over the head of the
male post by using a round bur of the proper size to remove the acrylic in the
chamber beyond the O-Ring, instead of covering the post with hot sticky
wax. This should be done after the processing O-Ring has been removed and
before the new O-Ring is inserted.
Optional: In Lab
Processing of the O-Ring into Dentures
1. Process denture on a duplicate model with the
area around attachment with O-Ring in place blocked out. Return to master
model to check fit and make occlusal adjustments. Undercut areas on master
model may be cut away but retain adequate landmarks to seat and secure denture
accurately.
2. Follow steps 10-14 of the previous overdenture
section.
3. The denture may not seat completely back on the
model, but tissue resiliency will let it seat in the mouth.
4. The spare O-Rings should be delivered in the
PREAT box with completed denture for future replacements.
Optional: Processing of
O-Rings into Overdentures on a Jigged Model
1. The denture is seated and the void areas around
the male post and coping should be free of contact.
2. The denture is worn for several days and normal
adjustments are made.
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6 |
3. When a patient is comfortable
with the denture and you are ready to process the O-Ring into the denture,
drill a hole from the lingual of the denture through to the void area around
the attachment (FIG 6). Fill the pressure relief groove
in the head of the male post with soft wax.
4. Fill the void area with rubber base
impression material and reseat the denture.
5. Remove the denture and place the processing
jigs into the impression of the male posts. Block out with soft wax
any undercut areas of the denture so that it can be easily removed from the
stone model after it sets. |
6. Pour the stone model and separate from the
denture after it has set. The jigs will be retained in the model in
exactly the same position as in the mouth. Remove the impression material
from the denture.
7. Follow steps 10-14 for processing O-Rings.
Metal OSO Retainer Rings
The surgical stainless steel retainer ring for the OSO
attachment aids in the seating and replacement of the rubber O-Ring and helps to
preserve the acrylic around the opening. The Retainer Ring can be placed
flush with the gingival of the denture, thereby reducing the height necessary
for the male post, if so desired.
After casting or after cementing the Male Post, seat the
red processing Ring into the Retainer Ring and put in place on the male
attachment. Block out the gingival portion of the Retainer Ring down to
the coping or base. The balance of the processing is as usual.
T0048.REV.01
*thanks to Brian at Signature Dental
Laboratory, Fayettvile, NC
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