|
|
Male in the post coping
Techniques for Direct, Indirect, and chrome
framework
 |
 |
| 691A |
RA 0091 |
Direct Method
| First, place the large space maintainer
over the post/coping area. For resilient prosthesis, use the large tin spacer.
Without the large tin spacer, the prosthesis is rigid, or abutment supported.
The small space maintainer must always be used
(FIG 1),
whether for resilient (tissue supported) or rigid (abutment supported)
prosthesis. Place the
acrylic retention female over the male spring
pin threaded in to the coping in the mouth (FIG 2).
Place self curing resin in the prosthesis (FIG
3). Seat the denture passively--Do
not have the patient bite. A lingual escape vent is always
recommended. Use light finger pressure over the attachment
area. |
|
Important: Use
the big tin spacer
The tin spacer
is used over the crown--or coping--during processing to block out excess
acrylic from locking in the attachment female.
However, the main reason for using the big
spacer can be understood by viewing figures
A
and B.
|
A |
B |
|
Figure A
is a Ceka overdenture case fabricated
without the large spacer.
This eliminates
all movement of the prosthesis--it is a rigid attachment. As you can see, the denture base is in direct contact with the
post coping (arrow). Forces are directed to the post coping abutment.
Figure B is the same overdenture case,
only this time the large spacer was used.
Using the large spacer allows for movement of
the prosthesis--it is now a resilient attachment.
During processing, the large spacer creates a free space between the prosthesis and the
post coping to allow this free movement, and
direct forces to the tissue. The greater the area the forces are spread over, the less force that is generated on
the abutment.
|
| The female is accurately positioned (FIG
4). |
4 |
Indirect Method
| The small space maintainer must always be used
(FIG 1),
whether for resilient (tissue supported) or rigid (abutment supported)
prosthesis. Place the
large tin spacer on the model (FIG 2),
then the
acrylic retention female over the male. Without the large tin spacer, the prosthesis is rigid, or abutment supported.
Block out any undercuts (FIG 3). |
|
4 |
5 |
| Process the denture (FIG
4). The female is accurately
positioned (FIG 5).
|
Chrome framework--Bonding
Technique
| Prepare an accurate refractory model (FIG
1). Wax a hood, or
cover, a minimum of 0.4mm over the attachment (FIG
2). Complete and finish the casting
(FIG 3). |
| The cast reinforcement is equally thick to the lingual (FIG
4).
Blast the internal surface with 110u aluminum oxide prior to bonding (FIG
5). Mix
equal parts Ceka Site base and catalyst. Apply to casting (FIG
6). Note that a fresh mixture of
Ceka Site is needed for each individual unit. |
| The assembled attachment, with the female and small space
maintainer (FIG 7). Seat the cast frame, with Ceka Site, over the attachment and allow
to seat for a full 10 minutes. Make a fresh batch
of Ceka Site for each unit. It is easy to remove the excess Ceka Site from the
polished post coping, as Ceka Site is anaerobic, and the
material in contact with air will not set (FIG
8). The bonded female is resistant to the heat of acrylic
resin processing (FIG 9). |
Chrome framework--Acrylic
Technique
| The acrylic retention female (FIG
1). An alternative to
bonding would be to directly process the female in to the acrylic resin (2-3).
Seat the small space maintainer on the female. Seat the framework.
Thread the spring pin into the acrylic retention cap and seat in female,
over framework. Process acrylic. Remove spacer |
T0032.REV.00
|
