Enhanced surface properties and wettability of zirconia-hydroxyapatite-poly(acrylic acid) nanocomposites for dental applications

Abstract

Introduction

Dentine demineralization is a key factor in dental caries and structural deterioration, necessitating the development of effective restorative approaches. Hydroxyapatite (HA) and zirconia (Zr) are widely used in dentistry due to their biocompatibility and mechanical strength; however, their individual remineralization potential is limited by poor surface characteristics. Polyacrylic acid (PAA), a biocompatible polymer, can be incorporated as a surface modifier to enhance the remineralization ability and interfacial properties of HA-Zr based restorative materials.

Materials and methods

In this study, PAA modified hydroxyapatite-zirconia (HA-Zr) nanocomposite (HA-Zr-PAA) was synthesized and characterized. X-ray diffraction (XRD) analysis was performed to confirm phase purity and crystallite size. Fourier transform infrared spectroscopy (FTIR) was used for functional group analysis. Vickers microhardness testing evaluated mechanical properties, while surface roughness and wettability studies assessed the surface characteristics relevant to remineralization.

Results

XRD confirmed phase pure HA with an average crystallite size of 34.11 nm and the presence of ZrO₂ peaks, indicating successful zirconia incorporation without secondary phases. FTIR analysis revealed the integration of HA, Zr, and PAA functional groups. Vickers microhardness improved from 224.45 MPa for HA to 285.67 MPa for HA-Zr-PAA, indicating enhanced mechanical strength. Surface roughness and wettability studies demonstrated increased surface roughness and hydrophilicity, promoting bioactive ion remineralization on dentine surfaces.

Conclusion

These integrated structural, mechanical, and surface modifications demonstrate that HA-Zr-PAA is a promising candidate for dentine remineralization and durable restorative dental applications.