INTRODUCTION

Nanofilled glass ionomer cement emerged as a new generation of dental materials, which mineralizes gradually into fluorapatite to improve the compressive strength and wear resistance of class II restorations in primary molars. The purpose of the study was to evaluate clinically the effectiveness of glass carbomer cement with surface coat as class II restorations in primary molars in comparison to both of Ketac N 100 glass ionomer cement and conventional glass ionomer cement with surface coat (Equia Fill). The null hypothesis of the current study was expecting no differences between the glass carbomer cement, ketac N glass ionomer cement and the conventional glassionomer cement in the clinical assessment.

ABSTRACT

Objective:

The aim of this study was to evaluate the effect of different concentrations of titanium dioxide nanoparticles on the mechanical properties of heat polymerized acrylic resin before and after thermocycling. The tested parameters were flexural strength and hardness.

Material and Methods: 120 specimens were prepared according to the specific dimension for each test (flexural strength and micro hardness) and distributed into: - Before thermocycling (control, (TiO2) nanoparticles with concentration (0.1% and 0.2%). - After thermocycling (control, (TiO2) nanoparticles with concentration (0.1% and 0.2%). Thermal cycles were performed in a thermocycling machine consisted of 5000 cycles at 5°C and 55°C. Results: Flexural strength and micro hardness were tested for both groups. The data was collected and statistically analyzed. Both Flexural strength and micro hardness were decreased by adding TiO2 nano particles concentrations.

Conclusion: adding (TiO2) nanoparticles to methyl methacrylate adversely affects the flexural strength and micro hardness before and after thermocycling.