Bone Quality Classification
A system—most commonly Lekholm and Zarb's D1–D4 scale—categorising jawbone according to the ratio and density of cortical to trabecular bone, guiding implant protocol selection.
Full Definition
Bone quality in implant dentistry is typically described using the D1–D4 classification introduced by Lekholm and Zarb, later modified by Misch into QI–QIV. D1 (or QI) denotes dense homogeneous cortical bone with poor vascularity, while D4 (or QIV) represents fine trabecular bone with minimal cortical support. Bone quality assessment influences drilling protocol, implant design selection, and loading timelines. Editors should note that 'bone quality' is distinct from 'bone quantity' (which concerns volume) and should not be conflated with 'bone density classification,' which focuses on radiographic density values rather than the histological composition described here.
Usage
Usage note: Distinguish from 'bone density classification,' which specifically addresses radiographic Hounsfield unit ranges rather than the Lekholm–Zarb histological framework.
In Context
- "The surgeon documented D3 bone quality in the posterior maxilla, prompting a bicortical stabilisation strategy." — Surgical planning report
- "The editor confirmed that the article consistently used D1–D4 notation rather than mixing it with the QI–QIV system midway through the methods section." — Copy-editing check