INTERFERENCES
q Certain areas of mouth may present interferences to easy insertion and removal of the prosthesis
q These interferences has to be identified with a surveyor and eliminated
Interferences can be dealt with by
q Elimination – extraction , ablation
q Alteration – disking , surgery, restoration
q Avoidance - modification of the design
q Exploitation – using it as an undercut to help retain the prosthesis
Interferences in mandible
q Lingual torus-
q Lingually tipped teeth
q Areas lingual to the retromolar pad
q Tilting of the cast
q Acrylic in the denture base can be relieved
q Bony prominences at the facial surface of canines and premolars
q Placement of denture base
q Positioning of approach arm of vertical projection clasp
Interferences in maxilla
q Torus palatinus
q Exostoses and undercuts ( buccal surfaces)
q Buccally inclined teeth
q Unilateral – tilting the surveying table away from the height of contour will lower the height of contour in the buccally tipped teeth
q Bilateral-
q Contouring of the enamel
q Full crown restoration
q Undercuts in anterior edentulous space
