Which bone condition carries the WORST prognosis for dental implant placement?

Correct answer: D. Osteopetrosis

• A. Resolved osteomyelitis is a historical concern requiring assessment of the healed site, but once the infection has cleared and bone has remodelled, implants can be placed. It is not the worst of these options.
• B. Paget disease in remission is a relative concern — the disorganised bone and hypervascularity in the active phase complicate surgery — but it does not carry the absolute remodelling failure of osteopetrosis.
• C. Osteoporosis is NOT a contraindication to implants. Success rates are comparable to healthy bone; it simply calls for careful site preparation, possibly undersized osteotomy, and longer healing. The real concern in these patients is usually the antiresorptive medication rather than the bone density itself.
• D. CORRECT. Osteopetrosis — 'marble bone disease' — results from defective osteoclast function, so bone is laid down and never remodelled. The result is dense, brittle, avascular bone with obliterated marrow spaces. That combination is uniquely hostile to implants: osseointegration depends on remodelling, and remodelling is the exact process that is absent. The compromised vascularity also carries a high risk of osteomyelitis after any surgical insult, and these patients have poor healing generally.

Note: Reason from the biology, not the name. Osseointegration REQUIRES osteoclastic remodelling. Any condition that abolishes remodelling (osteopetrosis) or profoundly suppresses it (high-dose IV bisphosphonates, denosumab) is a far greater threat than one that merely reduces bone density (osteoporosis).