Dental composites based on hybrid and surface-modified amorphous calcium phosphates

Area of Science:

• Materials Science
• Biomaterials Engineering
• Dental Materials

Background:

• Dental composites require enhanced mechanical properties and remineralization potential.
• Amorphous calcium phosphates (ACPs) offer mineral release but need improved stability.
• Surface modification and hybridization are strategies to enhance filler performance.

Purpose of the Study:

• To prepare hybrid and surface-modified ACP fillers for dental composites.
• To evaluate the impact of modifications on mechanical strength (biaxial flexure strength - BFS) and remineralization potential.
• To assess the stability of modified ACPs in dental composite formulations.

Main Methods:

• Hybridization of ACP with tetraethoxysilane or zirconyl chloride.
• Surface treatment of ACP with 3-methacryloxypropoxytrimethoxy silane (MPTMS) or zirconyl dimethacrylate (ZrDMA).
• Fabrication of composites using modified ACPs and various resin systems (BTH, BTHS, BTHZ).
• Testing of remineralizing potential (ion release) and biaxial flexure strength (BFS).
• Analysis of filler distribution using FTIR microspectroscopy.

Main Results:

• All composites demonstrated ion release above the minimum for apatite reprecipitation.
• BTHZ composites (ZrDMA modified) showed excellent stability in saline solutions, unlike BTH and BTHS composites.
• Filler hybridization significantly improved the BFS of BTHZ composites by up to 24%.
• FTIR analysis revealed heterogeneous ACP distribution, potentially hindering interfacial interactions and mechanical strength.

Conclusions:

• Surface modification with ZrDMA enhances the mechanical stability of ACP-filled dental composites.
• Hybridization of ACP with ZrDMA offers a promising approach to improve dental composite strength and stability.
• Careful control of ACP particle distribution is crucial for optimizing filler-resin interactions and composite performance.