When the denture base is forced to move away from the basal seat,it tends to rotate around one of the imaginary fulcrum lines.Those parts of a denture which provide resistance to rotation around a fulcrum axis by acting on the opposite side of the axis to the displacing force are called indirect retainers.They should be placed as far as possible from the distal extension base affording the best possible leverage advantage against lifting of the distal extension base.

    Functions of indirect retainers

    1,Contact of its minor connector with axial tooth surfaces aids in stabilizationagainst horizontalmovement of the denture.

    2,Anterior teeth supporting indirect retainers are splinted against lingual movement.

    3,It may act as an auxiliary rest to support a portion of the major connector.

    4,It may provide the first visual indications for the need to reline an extension base partial denture.

    5,It tends to reduce anteroposterior tilting leverages on the principle abutment teeth.This is particularly vital when an isolated tooth is being used as an abutment.

• Direct retainers
• Denture base