Attachments for Fixed & Removable Cases
C&B Semi-precision/extracoronal attachments
Semi-precision partial dentures are retained in the mouth by means of mechanical interlocking
components. A specially shaped extension of the partial denture fits into or onto a complementary
receiving area or projection of a natural tooth that has been crowned. The components fit snugly and
consist of a semi-rigid metal to other surface interface, which may also be metal or some other resilient
material such as nylon.
Extracoronal Precision attachments are normally resilient to allow free movement of the prosthesis to distribute potentially destructive forces or loads away from the abutments to supportive bone and tissue. Three distinctive movements are defined in function: (1) hinge, (2) vertical, and (3) rotational. The fewer abutments remaining, and the weaker the abutments are, the greater the need for resiliency or free movement to direct the forces away from the abutments to the supportive bone and tissue via the base of the prosthesis.
Advantages of semi-precision/extracoronal partial dentures:
- A cosmetically enhanced cast partial denture as compared to conventional cast partial dentures which utilize cast clasps
- Blends in with the conformity of remaining natural teeth
- Functions with a more even pressure on remaining natural teeth than conventional partial dentures
- Less tooth reduction is required for the crown than with an intracoronal attachment. Also, the crown can be made an ideal width since it does not have to accommodate an
- Extracoronal precision attachments are typically easier to insert and remove. These are ideal for patients with limited manual dexterity, or the prosthesis has a difficult path of insertion and removal.
- Intracoronal females in retaining crowns will collect food and present problems when the patient attempts to seat the intracoronal retained prosthesis. Extracoronal attachments do not present this problem.
Overdentures offer prosthesis retention for the patient suffering from retention problems with the typical complete denture, particularly those patients with advanced ridge resorption. Overdentures obtain their support from two or more abutments by completely enveloping them beneath the fitting surface. (The use of only one abutment is not recommended.) Overdentures offer these patients greatly improved retention and stability. “The overdenture attachment can be placed in tooth roots that have been saved, or torqued into dental implants which have been placed to receive them.
For information on screw retained overdentures, commonly referred to as fixed detachables, please refer to the Fixed Detachables page of our site.