All are true about lingual ledges except:: (A) Part of tooth preparation for a resin bonded retainer, (B) Increases the retention and resistance form, (C) Decreases the casting rigidity, (D) Aids in orientation of the casting during cementation
Answer is C. Lingual ledges are small horizontal grooves placed on the lingual aspect while preparing a tooth for resin bonded retainers. These increase the retention and resistance forms, increase casting rigidity and aid in orienting the casting while cementation of the prosthesis.