- It is defined as a device, which relieves the abutment tooth of all or part of the occlusal forces (GPT)
- In order to minimize the stress in the case of distal extension partial denture, devices like stress breakers are used.
- Type I = In this type, a movable joint is placed between the direct retainer and denture base.
- Type II = This type consists of a flexible connection between the direct retainer and the denture base.
- Advantages
- Preservation of the alveolar support of abutment
tooth due to the reduction of stress on it. - Balanced stress on residual alveolar ridge and
abutment. - Weak abutment teeth are well splinted even when
the denture base is moved. - Even if relining is not done properly, abutment
teeth are not damaged. - Direct retention is less required.
- A massaging effect is produced on the soft tissues during the movement of the denture base.
- This lessens the need for frequent relining and rebasing.
- Preservation of the alveolar support of abutment
- Disadvantages
- Complicated design and expensive.
- Weak assembly and fractures easily.
- It distorts due to rough handling.
- It is difficult to repair.
- It can counter only the vertical forces on the
denture. - Reduced stability against horizontal forces.
- Inappropriate relining leads to excessive ridge resorption.
- Reduced indirect retention.
- The split major connector tends to collect food
debris at the area of split.