Which systemic bone condition presents the GREATEST risk of implant failure due to impaired osseointegration?

Correct answer: D. Osteopetrosis

• A. ❌ Osteomalacia is defective mineralization from vitamin D deficiency and is correctable medically.
• B. ❌ Osteomyelitis is an acute or chronic infection — a contraindication while active, but treatable, after which implants may be placed.
• C. ❌ Osteoporosis reduces bone density but remodeling remains intact; implant survival rates are close to normal, with slower healing and often a longer loading protocol.
• D. ✅ CORRECT — OSTEOPETROSIS ('marble bone disease') is caused by defective OSTEOCLAST function. Bone is dense but avascular and cannot remodel, so the coupled resorption-formation cycle that osseointegration depends on cannot occur. These patients also have a high baseline risk of osteomyelitis after any surgery.

Note: The mnemonic that helps: osteoPETROSIS = 'petrified' bone = no osteoclasts = no remodeling = no osseointegration.