Paper Title
Preparation and Characterizations of Natural Hydroxyapatite-Yttria Stabilized Zirconia Composites for Dental Restorations

Abstract
Resin-based composite (RBC) resembles the color of teeth has been used as a popular dental materials to repair or restore damaged teeth. 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 determine 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. Different ration of YSZ (0, 10, 25, 50 and 75 wt%) was added to the natural hydroxyapatite (NHAp) powder and mixed with the blended resin. Then, composite was inserted into mould and light cured with LED polymerization unit for 60 s on the both sides. The flexural strength, compressive strength, Vickers hardness and surface roughness of composites were measured. The NHAp2 exhibited satisfactory mechanical properties with a flexural strength, compressive strength, Vickers hardness and surface roughness of 65.61 MPa, 160.34 MPa, 50.80 HV and 120.00 nm, respectively. These results suggested that the natural hydroxyapatite incorporating with YSZ is a promising material for dental composites. Keywords- Hydroxyapatite, Yttria Stabilized Zirconia, mechanical properties, dental composite