The
Original OSO
O-Ring System
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The
Original OSO
O-Ring System |
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Castable Male overdenture pattern.
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FDA Approved Rubber O-Ring OSO O-Ring size chart available
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FDA Approved Processing O-Ring
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Metal Housing for O-Rings
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OSO Overdenture Fabricating Jig One per package. For duplication and retention in stone models.
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Benefits:
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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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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| 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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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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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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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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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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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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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
