What caused the mobility and bone loss in this precision-attachment case?

Correct answer: A. Distal torque forces generated by the attachment on the RPD

• A. Correct. The mechanical design of certain precision attachments transmits distal torquing forces to the abutment tooth during function, contributing to mobility and localized bone loss if not properly managed (e.g., via splinting).
• B. While oral hygiene matters generally, the specific biomechanical cause identified in this case is the attachment's torque forces, not hygiene alone.
• C. Bruxism is not specified as the cause in this case; the biomechanical attachment design is the highlighted cause.
• D. There's no indication of caries under the crown in this scenario; the cause is biomechanical (attachment torque).