Which Lekholm and Zarb bone quality classification type represents the DENSEST bone found at implant sites?

Correct answer: D. Type 1

• A. Type 4 bone has a very thin cortical shell with low-density cancellous bone — the poorest quality for implants, most common in the posterior maxilla. Highest implant failure risk.
• B. Type 3 bone has a thin cortical shell with dense trabecular bone — moderate density, found in the posterior mandible and anterior maxilla.
• C. Type 2 bone has a thick cortical shell with a dense cancellous core — excellent for implants and found in the anterior mandible and posterior maxilla.
• D. CORRECT. Type 1 bone consists of homogeneous, dense cortical bone with little or no cancellous component. It is found most commonly in the anterior mandible. While Type 1 provides excellent initial implant stability, it has reduced vascularization which can slow osseointegration. High insertion torque without overheating is critical.