Effect of yttria stabilised zirconia addition in natural hydroxyapatite composites for dental restoration

Resin based composite (RBC) resembles the color of teeth has been used as a popular dental materials to repair or restore damaged teeth. In this study, the RBC were prepared using a hydroxyapatite from fish scales and yttria stabilised Zirconia as reinforcement fillers, while the organic resin are the blended monomers of Bis-GMA, TEGDMA and UDMA. The aim of this study is to assess the effect of addition of yttria stabilised Zirconia (YSZ) on the mechanical properties of natural hydroxyapatite resin-based composites for dental restoration. The composites were prepared in ratio 30:70 wt% of organic resin and inorganic filler, respectively. For inorganic filler, different ration of YSZ (0, 10, 25, 50 and 75 wt%) was added to the natural hydroxyapatite (HAp) powder and mixed with the blended resin. The RBC was inserted into mould and light cured with LED polymerization unit for 60 s on the both sides. The flexural strength, compression strength, Vickers hardness and surface roughness of composites were measured. The HAp-YSZ composite with 10 wt% YSZ filler content exhibited satisfactory mechanical strength with a flexural strength, compression strength, Vickers hardness and surface roughness of 65.61 MPa, 158.20 MPa, 50.80 HV and 120.00 nm, respectively. These results suggested that the strong mechanical properties of RBCs are important for the long-term clinical application of dental restorative materials