Impedance changes during setting of amorphous calcium phosphate composites

Area of Science:

• Materials Science
• Biomaterials Engineering
• Electrochemistry

Background:

• Dental composites require reliable methods to assess curing and properties.
• Amorphous calcium phosphate (ACP) offers potential for bioactive dental materials.
• Understanding the electrical behavior of ACP composites is crucial for their development.

Purpose of the Study:

• To investigate the electrical properties of experimental light-curable composite materials based on amorphous calcium phosphate (ACP).
• To correlate electrical measurements with material characteristics like degree of conversion and water content.
• To evaluate impedance spectroscopy as a method for characterizing ACP-based composites.

Main Methods:

• Impedance measurements were performed at various frequencies (1kHz to 1MHz) over 24 hours.
• Electrical resistivity changes during curing were analyzed to extract kinetic parameters.
• Results were correlated with Raman spectroscopy, gravimetry, light transmittance, and SEM.

Main Results:

• ACP-based composites exhibited higher immediate conversion but lower polymerization rates compared to controls.
• Electrical conductivity correlated with water content from ACP fillers.
• A strong correlation was observed between degree of conversion and electrical resistivity.

Conclusions:

• Impedance spectroscopy is a valuable tool for characterizing ACP-based composites.
• Electrical properties provide insights into the curing and composition of these materials.
• Further development of ACP composites can be advanced through a better understanding of their electrical behavior.