Which cells are primarily affected by bisphosphonates (e.g., alendronate, zoledronate)?

Correct answer: C. Osteoclasts

• A. Fibroblasts are not the primary target of bisphosphonates.
• B. Odontoblasts (dentin-forming cells) are not affected by bisphosphonates.
• C. OSTEOCLASTS are the primary target of bisphosphonates. Bisphosphonates are incorporated into bone and when osteoclasts attempt to resorb that bone, the bisphosphonate is released and causes osteoclast APOPTOSIS (programmed cell death). This reduces bone resorption. However, accumulated bisphosphonate in jaw bone prevents healing after dental extractions/surgery, leading to MRONJ (medication-related osteonecrosis of the jaw).
• D. Osteoblasts (bone-forming cells) are not the primary target of bisphosphonates. Some indirect effects on osteoblast signaling occur, but they are not the mechanism of action.