14/07/2026
Dentistry credit
“Good bone / bad bone” is lazy. Misch gave us four types — and each one changes your drill. 🦴
Carl Misch classified bone density into D1–D4, based on the tactile resistance you feel while drilling (and mirrored on CBCT in Hounsfield units). Knowing the type before you pick up the handpiece is half the case.
D1 — Dense cortical 🌳
Feels like drilling oak or maple. >1250 HU. Classic anterior mandible.
→ Amazing primary stability, but poor blood supply and real overheating risk. Sharp drills, copious irrigation, don’t rush.
D2 — Porous cortical + coarse trabecular 🌲
Like white pine / spruce. 850–1250 HU. Anterior/posterior mandible, anterior maxilla.
→ The sweet spot: great stability and good vascularity. Most predictable bone to place into.
Dentistry
D3 — Thin cortical + fine trabecular 🪵
Like balsa wood. 350–850 HU. Maxilla, posterior regions.
→ Lower bone-to-implant contact. Undersize the osteotomy, ease off the final drills.
D4 — Fine trabecular, almost no cortex 🧊
Like styrofoam. 150–350 HU. Posterior maxilla — especially molars and post-sinus-graft sites.
→ The tough one. Poor primary stability. Undersized prep, osteotomes or osseodensification, consider healing time before loading.
Does it actually change survival? A review of 12,465 implants: D1 97.6% · D2 96.2% · D3 96.5% · D4 88.8%. 📉
But here’s the real lesson — Misch’s own multicenter data showed that when bone is assessed correctly and the protocol is adapted, success rates converge across all types. The bone isn’t “bad.” An unadapted protocol is. 🎯
Save this for your next planning session. Which type do you find trickiest — the rock-hard D1 or the styrofoam D4? 👇
