debonding

Debonding refers to the separation of two surfaces that have been bonded together, resulting in loss of adhesion. It can occur in a wide range of fields, including dentistry, materials science, and engineering, wherever bonded joints or adhered layers are subjected to stresses, moisture, or temperature changes.

In dentistry, debonding denotes the removal of orthodontic brackets, bands, or other appliances after treatment. The adhesive resin is weakened or broken so the appliance can be removed with minimal damage to enamel. Clinicians often use specialized tools and may assess adhesive remnants via the Adhesive Remnant Index (ARI). After removal, enamel surfaces are cleaned and polished, and fluoride treatment may be applied to protect enamel.

In composites and bonded joints, debonding describes failure at the interface between substrate and adhesive or within one layer, separating components. It is a common failure mode under mechanical loading, thermal cycling, or moisture exposure. Modes include adhesive debonding (at the interface), cohesive debonding (within adhesive), or substrate fracture. It compromises structural integrity and may progress if moisture ingress continues.

Diagnosis and prevention involve both testing and material/process choices. Non-destructive methods such as visual inspection, microscopy, acoustic emission, and ultrasonic testing help detect debonding, while mechanical tests (for example, lap shear) are used in laboratories. Prevention focuses on proper surface preparation, appropriate priming, compatible adhesive selection, correct curing, environmental control, and sound design to minimize stresses at bonded interfaces.