Implant planning in compromised bone

Correct answer: D. Osteopenia

• A. Focal osteosclerosis is a localised increase in bone density with no systemic significance and no reduction in mineral content.
• B. Fibrous dysplasia replaces normal bone with poorly organised fibro-osseous tissue and is generally avoided for implants, but the mechanism is disorganised architecture and expansion rather than a measured reduction in mineral density.
• C. Osteopetrosis is the OPPOSITE problem — a failure of osteoclastic resorption producing abnormally dense, brittle bone with obliterated marrow spaces. Implants fail there not from low density but from poor VASCULARITY, from overheating during the osteotomy in dense bone, and from a high risk of osteomyelitis. It is a genuine contraindication, but not because of reduced density.
• D. CORRECT. OSTEOPENIA is reduced bone MASS and mineral density that has not yet reached the osteoporosis threshold (T-score between −1.0 and −2.5). Lower density means poorer primary stability at placement and reduced bone-to-implant contact. Where OSTEOPOROSIS is not offered among the options — as the recall reports — osteopenia is the intended answer, since it is the same process at an earlier stage. Two caveats worth carrying: a DEXA result at the spine or hip does NOT reliably predict jaw bone quality, so this is a relative rather than absolute concern; and in these patients the far greater implant-related risk is ANTIRESORPTIVE THERAPY, not the density itself.

Note: ⚠️ The recall notes osteoporosis was absent from the option list, which is what makes osteopenia the key. Osseointegration failure in osteoporotic patients is attributed to reduced bone mass and density, but the skeletal diagnosis at one site does not necessarily reflect the maxilla and mandible. INTRAVENOUS bisphosphonate use is the finding that genuinely changes the plan.

Correct answer: D. Reduced bacterial adhesion to the implant surface with a favourable soft-tissue response

• A. Zirconia implants are generally MORE expensive than titanium, not less.
• B. Fracture toughness is zirconia's WEAKNESS relative to titanium, not its strength. Zirconia is a ceramic — it is brittle, subject to crack propagation and to low-temperature degradation (ageing) in a wet environment, and one-piece designs cannot be angle-corrected after placement. This is the principal reason titanium remains the default.
• C. Narrow ridges argue AGAINST zirconia. Because it is brittle, narrow-diameter zirconia fixtures carry a meaningful fracture risk, whereas titanium tolerates reduced diameters far better.
• D. CORRECT. Zirconia shows LOWER BACTERIAL ADHESION and less plaque accumulation on its surface than titanium, together with a favourable soft-tissue response and excellent biocompatibility. It is also highly resistant to CORROSION, avoids the grey show-through visible at a thin buccal gingiva, and is an option for the small number of patients who report titanium hypersensitivity.

Note: Titanium remains the standard of care on the strength of decades of documented survival data and the restorative flexibility of two-piece designs. Zirconia's case rests on soft-tissue response, esthetics in a thin biotype, and the absence of metal — not on mechanical superiority.