The Effect of Zirconium Oxide addition on Heat Cured Temporary Acrylic Resin Restoration of Fixed Dentures towards Flexural Strength and Surface Hardness

Abstract

Purpose: The fabrication of temporary restorations is aimed to protect oral tissues, aesthetical purposes and
maintaining the function of mastication until a permanent restoration is finished. The purpose of this study is to determine the
effect of adding ZrO2 nanoparticles with concentrations of 5% and 7% to HCAR material of fixed dentures on its flexural strength
and surface hardness. The design of this study is an experimental laboratory.
Materials and Methods: HCAR temporary restoration material samples without the addition of reinforcing agents,
with the addition of ZrO2 nanoparticle reinforcement (5%, 7%) for flexural strength test (10 x 65 x 2.5 mm) and surface hardness
test (10 x 30 x 2.5 mm). Each sample is tested for flexural strength and surface hardness and then analyzed with a univariate
test to determine the mean value and standard deviation of each group. T-test to determine the effect of the addition of ZrO2
on flexural strength and surface hardness of the HCAR on fixed dentures. The data were normal and homogeneous p = 0.65 (p>
0.05).
Results: Flexural strength test on the HCAR temporary restoration material without the addition of reinforcing
material and HCAR temporary restoration material with the addition of 5% ZrO2, p = 0.001 was obtained; in the HCAR
temporary restoration material without the addition of reinforcement material and HCAR temporary restoration material with
the addition of 7% ZrO2, p = 0.001 was obtained, so there were significant differences in the flexural strength values of the
three groups. In the surface hardness test of the HCAR temporary restoration material without the addition of reinforcing
materials and on the HCAR temporary restoration material with the addition of 5% ZrO2, p = 0.887 was obtained. In the surface
hardness test of the temporary restoration of HCAR temporary restoration material without the addition of reinforcing material
and HCAR temporary restoration material with the addition of 7% ZrO2, p = 0.044 was obtained.
Conclusion: The addition of 5% ZrO2 and 7% ZrO2 can reduce the flexural strength of HCAR temporary restorations but
can increase the hardness value of the HCAR temporary restoration surface with the addition of ZrO2 7% so that the HCAR
temporary restorations of fixed dentures becomes stronger and is not easily fractured and lose its wear resistance when it is
given specific load especially in cases of fixed denture fabrication which requires a long laboratory process such as long span
and multi-unit fixed denture.