How a wound seals, cleans itself, and rebuilds — and why, on an implant, the fibrin clot becomes the scaffold osteogenic cells crawl along to lay down bone directly on the surface.
Use: Basic-science referenceTheme: Clot to osseointegrationAnchor: Davies healing model
01 — Concepts
The four overlapping phases of healing
Soft- and hard-tissue repair follow the same cascade — hemostasis, inflammation, proliferation, remodeling. The phases overlap rather than run in strict sequence, and on an implant surface the same biology produces osseointegration.
Select a phase below to expand the dominant cells, molecular events, and — where relevant — what is happening at the implant surface during that window.
Tap a phase. On an implant, hemostasis and proliferation map directly onto osteoconduction and de novo bone formation.
Which phase do you want to explore?
PHASE 1
Hemostasis & fibrin clot
Minutes to hours — the scaffold forms.
PHASE 2
Inflammatory phase
Days 1–7 — debridement and signaling.
PHASE 3
Proliferative phase
Days 3–14+ — granulation and angiogenesis.
PHASE 4
Remodeling / maturation
Weeks to a year — lamellar bone, strength.
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03 — Quick Reference
Phase, timeframe, and key cells / events
Timeframes are approximate and overlap; they are slower in soft, grafted, or compromised sites. The right column links each phase to the peri-implant event described in Davies' model.
Phase
Timeframe
Key cells / events
At the implant surface
Hemostasis
Minutes – hours
Platelets, fibrin clot, PDGF/TGF-β release
Fibrin scaffold attaches to surface
Inflammation
Days 1–7
Neutrophils then macrophages; debridement
Clot retains, cells recruited
Proliferation
Days 3–14+
Fibroblasts, angiogenesis, granulation tissue
Osteoconduction + de novo bone
Remodeling
Weeks – 1 year
Osteoclasts/osteoblasts; woven → lamellar bone
Contact osteogenesis matures, bonding
Reference
Sources & clinical disclaimer
For licensed clinicians — educational use only. This page summarizes published basic science and is not a substitute for individual clinical judgment, examination, or the standard of care in your jurisdiction. Healing timeframes are approximate and vary with site, host factors, and surgical technique.
Terheyden H, Lang NP, Bierbaum S, Stadlinger B. Osseointegration — communication of cells. Clin Oral Implants Res. 2012;23(10):1127–1135.
Berglundh T, Abrahamsson I, Lang NP, Lindhe J. De novo alveolar bone formation adjacent to endosseous implants. Clin Oral Implants Res. 2003;14(3):251–262.
Last reviewed: June 2026 · Next review due: June 2027 · Version 1.0
Self-Test
Self-Test
Switch between board-style single-best-answer questions and oral-defense prompts. Commit to an answer before revealing.
1. In the first minutes to hours after implant placement, the structure that adheres to the implant surface and becomes the scaffold for osteogenic cell migration is the:
A is correct. Hemostasis converts fibrinogen to fibrin, forming a clot that adheres to the implant surface. This fibrin scaffold is the cable along which osteogenic cells migrate (osteoconduction); granulation tissue, woven/lamellar bone, and the cement line come later.
2. In Davies' model of peri-implant healing, osteogenic cells migrating across the fibrin/implant surface to reach and lay down bone directly on it describes:
B is correct. Osteoconduction is the migration of osteogenic cells across the fibrin scaffold to the implant surface; those cells then secrete matrix and form bone directly on the implant — contact osteogenesis. Distance osteogenesis, by contrast, lays bone from the old bone wall toward the implant.
3. During the proliferative phase, which event is essential because it delivers the oxygen and nutrients that allow new tissue to be built in the defect?
C is correct. Angiogenesis brings new capillaries that supply oxygen and nutrients to granulation tissue, enabling fibroblast matrix deposition and de novo bone formation. Vasoconstriction is a hemostatic event; neutrophils dominate inflammation; osteoclastic remodeling occurs in the final phase.
4. A heavy smoker shows delayed osseointegration. The phase whose prolongation most plausibly stalls every downstream healing event is the:
B is correct. A prolonged or excessive inflammatory phase (as with smoking or infection) delays the recruitment of fibroblasts and osteogenic progenitors and pushes back proliferation and remodeling. Because the phases are sequential and overlapping, stalling inflammation delays everything downstream.
1. Walk the examiner through the four phases of wound healing and map them onto what is happening at the implant surface.
Model answer. The phases overlap rather than run strictly in sequence. (1) Hemostasis (minutes–hours): vasoconstriction then a platelet plug; the coagulation cascade converts fibrinogen to fibrin, forming a clot that is also a growth-factor depot (PDGF, TGF-β). At the implant, this fibrin scaffold adheres to the surface. (2) Inflammation (days 1–7): neutrophils then macrophages debride and signal, recruiting fibroblasts and osteogenic progenitors. (3) Proliferation (days 3–14+): granulation tissue and angiogenesis; osteogenic cells migrate across the fibrin to the surface (osteoconduction) and lay down a mineralized cement-line matrix producing woven bone — contact osteogenesis. (4) Remodeling (weeks–months): woven bone is replaced by lamellar bone via coupled osteoclast–osteoblast activity, underlying the rise in secondary stability.
Examiner follow-ups:
Which growth factors does the clot release and from where?
Where does osteoconduction sit in this timeline?
How does this map onto primary vs secondary stability?
2. Compare contact osteogenesis and distance osteogenesis, and justify why surface design favors the former.
Model answer. In contact osteogenesis, osteogenic cells migrate across the fibrin scaffold to reach the implant and form new bone directly on the surface (de novo), so mineralization proceeds toward the old bone. In distance osteogenesis, bone forms from the existing bone walls and grows toward the implant, so the surface is reached last. Contact osteogenesis is preferred because it produces earlier, more intimate bone-to-implant contact. It depends on the fibrin clot staying anchored to the surface so cells can migrate along it; a moderately rough, wettable surface retains the clot and resists its retraction during cell migration, which is why surface topography and hydrophilicity are engineered to promote it.
Examiner follow-ups:
Why does clot retention favor contact osteogenesis?
How does surface roughness influence which mode dominates?
What is a cement line and what is its role?
3. Explain the role of the fibrin clot in osseointegration and defend why preserving it surgically matters.
Model answer. The fibrin clot does three jobs: it seals the wound, acts as a growth-factor depot releasing PDGF and TGF-β from activated platelets, and — critically at an implant — forms the provisional scaffold that adheres to the surface and along which osteogenic cells migrate to enable osteoconduction and contact osteogenesis. If the clot detaches or retracts from the surface during cell migration, cells cannot reach the implant and bone forms at a distance instead, delaying intimate bone-to-implant contact. Surgically, atraumatic technique, adequate bleeding to seed the clot, primary stability so micromotion does not shear the clot, and a wettable surface that holds the clot all protect this scaffold and therefore protect early integration.
Examiner follow-ups:
How does excessive micromotion disrupt the clot?
Why does surface wettability help clot adhesion?
What growth factors does the clot supply and what do they do?