Hybrid Layer
The micro-anatomical zone formed at the adhesive–dentine interface where resin monomers infiltrate and co-polymerise within the demineralised collagen fibril network.
Full Definition
Coined by Nakabayashi et al. (1982), the hybrid layer (also called the resin-infiltrated dentine layer) is the critical structural unit of adhesive bonding to dentine. After acid etching removes hydroxyapatite from intertubular dentine, resin monomers permeate the exposed collagen mesh and polymerise in situ, creating a micrometre-thick interpenetrating polymer–collagen network. The quality and uniformity of hybrid layer formation determine long-term bond strength; incomplete infiltration leaves unprotected collagen susceptible to hydrolytic and enzymatic degradation. Editors should note that 'hybrid layer' is a two-word open compound; do not hyphenate.
Usage
Usage note: Write as an open compound: 'hybrid layer'. When an author uses 'resin-infiltrated dentine layer' and 'hybrid layer' interchangeably, ensure consistency is maintained throughout the manuscript.
In Context
- "TEM images demonstrated a well-defined hybrid layer of approximately 3–5 µm for the three-step total-etch adhesive." — Adhesive dentistry electron microscopy study
- "Degradation of the hybrid layer was identified as the primary mechanism of bond strength reduction over 12 months of water storage." — Longitudinal laboratory study