Evaluation of Shore A hardness of maxillofacial silicones: the effect of dark storage and nanoparticles

Year 2018, Volume: 52 Issue: 2, 99 - 104, 01.05.2018

Pınar Çevik

Abstract

DOI: 10.26650/eor.2018.469

Purpose

Little has been reported how the addition
of nanoparticles could affect the hardness of maxillofacial silicones. The
purpose of this study was to evaluate the effects of different types of
nanoparticle additives and dark storage for 2-years on the Shore A hardness of
two types of maxillofacial silicone elastomers.

Materials and Methods

A-2000 and A-2006 Room Temperature
Vulcanized (RTV) silicone elastomers were tested in this study. Silaned silica,
fumed silica and titanium dioxide nanoparticles at concentrations of 10% by
volume were used as fillers for the maxillofacial silicone elastomers. A total
of 64 silicone specimens were fabricated, which includes 8 samples, 30 x 10 mm
in size, from each silicone elastomers for each subgroup and also controls.
After the initial Shore A hardness measurements, specimens were kept in dark
conditions at room temperature for 2 years. The final measurements were then
taken from the silicone specimens. All data were statistically analyzed.

Results

For both types of silicones, there was
statistically significant differences among study groups (p<0.001). Fumed
silica group showed the lowest hardness values in A-2000 after storage.
However, no significant difference was observed between control and fumed silica
groups. Control group showed the lowest hardness values in A-2006, while the
highest hardness values were found in fumed silica group; there was no
significant difference between silica and silane groups.

Conclusion

Shore A values of the specimens were within
the acceptable range for the maxillofacial silicones after aging. Nanoparticle
addition did not prevent hardening of the silicone elastomers with time. 

Keywords

Aging; hardness; nanoparticles; silicone elastomers; Shore A

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