On average, free soft tissue autografts (like free gingival grafts) show roughly 20–25% vertical shrinkage by about 6 months, with many studies clustering in the 15–30% range depending on the protocol and measurement method.

Quick Scoop

  • Periodontal trials on free soft tissue autografts report mean vertical shrinkage around 21–23% at 6 months, regardless of whether certain flap margins are sutured or left free.
  • Earlier clinical work on free gingival grafts found total surface area shrinkage around 19% over 3 months, with vertical shrinkage generally in the same ballpark.
  • Reviews of autogenous soft tissue grafting emphasize that all grafts shrink to some degree, but free autografts tend to maintain a robust gain in keratinized tissue width even after this 20–25% loss.

So, if you harvest (or plan) your graft dimensions, a practical “rule of thumb” is to anticipate about one‑quarter reduction in height over the healing period and oversize accordingly.

What Affects That Percentage?

Key factors that can push shrinkage higher or lower include:

  1. Graft thickness and handling
    • Thicker grafts and careful handling tend to shrink a bit less but may be harder to adapt and vascularize.
    • Very thin grafts can contract more as they heal and remodel.
  2. Stabilization and immobilization
    • Secure suturing and good adaptation to a well‑prepared bed help reduce contraction.
    • Micromovement, hematoma, or poor contact can increase shrinkage.
  3. Recipient site and flap design
    • Some protocols (e.g., how far you advance or release neighboring tissue) change horizontal vs vertical shrinkage patterns, but average vertical loss still hovers around that 20% mark.
  1. Patient‑related factors
    • Local inflammation, oral hygiene, smoking, and systemic issues can all worsen remodeling and contraction.

Simple Chairside Example

Imagine you want a final vertical graft height of 5 mm.

  • If you anticipate ~20–25% shrinkage, you might harvest and place ~6.0–6.5 mm in height.
  • After healing, a 25% reduction of 6.5 mm is about 1.6 mm, leaving you close to your 5 mm target.

This is why many clinicians routinely oversize their free soft tissue autografts in both height and width, planning for that expected contraction rather than being surprised by it later.

Information gathered from public forums or data available on the internet and portrayed here.