Interfacial Characterization of Dentin Conditioned with Chitosan Hydroxyapatite Precursor Nanocomplexes Using...

Area of Science:

• Biomaterials Science
• Dental Materials
• Nanotechnology

Background:

• The tricalcium silicate (TCS) sealer-dentin interface is crucial for dental restoration longevity.
• Understanding chemical modifications at this interface is key to improving sealer performance.
• Chitosan-hydroxyapatite (C-HA) nanocomplexes offer potential for surface modification.

Purpose of the Study:

• To evaluate the effect of C-HA nanocomplex conditioning on chemical modifications at the TCS sealer-dentin interface.
• To analyze the formation of interfacial layers using advanced material characterization techniques.

Main Methods:

• Human premolar dentin slabs were prepared and conditioned with C-HA nanocomplexes.
• Tricalcium silicate sealer was applied, and samples were incubated for 10 days.
• Time-of-flight secondary ion mass spectrometry (ToF-SIMS) and transmission electron microscopy (TEM) were used for analysis.

Main Results:

• C-HA conditioning created an ion-rich layer with phosphates, hydroxide, and chitosan fragments at the interface.
• Control groups showed decreased calcium and calcium phosphate presence and lacked phosphate fragments.
• Ultrastructural analysis revealed a continuous 5 μm mineral layer in C-HA conditioned samples versus <1 μm in controls.

Conclusions:

• C-HA nanocomplex conditioning significantly modifies the dentin substrate before TCS sealer application.
• An ion-rich layer composed of phosphate, calcium, calcium phosphates, and chitosan is formed.
• This chemical modification enhances the sealer-dentin interface, promoting better integration.