Fluoridated hydroxyapatite nanorods as novel fillers for improving mechanical properties of dental composite: Synthesis and application

Fluoridated hydroxyapatite (FHA) in nanorod morphology and hexagonal cross section were synthesised via hydrothermal process using Apricot Tree Gum (ATG) as a surfactant. The synthesised FHA nanorods were then used as reinforcement in bisphenol A-glycol dimethacrylate (Bis-GMA) as base monomer of composite matrix. The FHA nanorods with different ratios were incorporated in the matrix to examine fluoride ion release and pH changes in the Simulated Body Fluid (SBF) and their mechanical properties. The resin without FHA reinforcement was used as the control sample. The Diametral Tensile Strength (DTS), Flexural Strength (FS), and Flexural Modulus (FM) of the reinforced composite were found to be higher compared to the control sample; the values increased from 34.8 to 45.4 MPa, 76.5 to 99.4 MPa, and 1.7 to 2.5 GPa, respectively. Moreover, findings revealed that the pH is reduced by releasing the fluoride ions into the SBF which can be effective for preventing secondary caries. The most optimum mechanical properties were achieved with 0.2 wt% of FHA reinforcement. The FHA nanocomposite meets the minimum standard requirements for dental applications and compared to other dental composites has advantage of preventing formation of secondary caries due to release of fluoride. (C) 2015 Elsevier Ltd. All rights reserved.