Background/Aim. The main drawback of flowable dental composite resin is low
strength compared to conventional composite resin, due to a low amount of
filler, neccessary for achieving low viscosity and ease of handling. The aim
of this study was to improve mechanical properties of flowable dental
composite resin by adding small amount of nanoparticles, which would not
compromise handling properties. Methods. A commercially available flowable
dental composite resin material was mixed with 7 nm aftertreated hydrophobic
fumed silica and cured by an UV lamp. Four sets of samples were made: control
sample (unmodified), the sample containing 0.05%, 0.2% and 1% nanosilica.
Flexural modulus, flexural strength and microhardness were tested. One-way
ANOVA followed by Tukey?s test with the significance value of p < 0.05 was
performed to statistically analyze the obtained results. Furthermore,
differential scanning calorimetry (DSC) and SEM analysis were performed. To
asses handling properties, slumping resistance was determined. Results. It
was found that 0.05% is the most effective nanosilica content. All the tested
mechanical properties were improved by a significant margin. On the other
hand, when 0.2% and 1% nanosilica content was tested, different results were
obtained, some of the mechanical properties even dropped, while some were
insignificantly improved. The difference between slumping resistance of
unmodified and modified samples was found to be statistically insignificant.
Conclusions. Low nanosilica addition proved more effective in improving
mechanical properties compared to higher additions. Furthermore, handling
properties are unaffected by nanosilica addition.
Effect of amylase activity on mechanical properties of dental composite resin
