What is the MINIMUM amount of bone height needed for safe implant placement?

Correct answer: C. 7 mm (minimum acceptable vertical bone height to accommodate a standard implant with safety margin)

• A. 2mm is far too little for any implant — it represents only the safety margin from the nerve, not total bone height.
• B. 12mm is ideal but more than the minimum requirement.
• C. Correct. While the answer in actual practice depends on implant length and anatomy, the MINIMUM VERTICAL BONE HEIGHT commonly cited in dental boards for implant placement is approximately 7mm (some sources state 1mm safety margin above the inferior alveolar nerve, plus the shortest available implant of ~6mm). Additionally, the implant should be at least 2mm away from the inferior alveolar nerve.
• D. 5mm is generally insufficient for most standard-length implants.