A Kennedy Class II partial denture patient with periodontal disease needs a design change to reduce stress on the distal-extension abutment. What is appropriate?

Correct answer: A. Place the rest on the mesial rather than the distal of the abutment

• A. Correct. A mesial rest (with an RPI/RPA-type design) allows the distal-extension base to rotate without torquing the abutment, reducing harmful stress — important with compromised periodontium.
• B. A distal rest acts as a fulcrum that levers/torques the abutment under loading.
• C. Removing rests eliminates needed support.
• D. A cantilever increases, rather than reduces, leverage on the abutment.