Effects of incorporation of nano particles on the mechanical properties of maxillofacial silicone elastomer subjected to outdoor weathering

Abstract

Statement of problemNatural weathering has varied effects on the service life of maxillofacial silicones due to its direct implications on the tear strength and hardness of the material. PurposeThe purpose of this study was to evaluate the effect of incorporation of nano oxides on the mechanical properties of maxillofacial silicone elastomer subjected to outdoor weathering. Material and methodsThis in-vitro study was conducted in the Department of Prosthodontics, on maxillofacial silicone elastomer samples incorporated with nano particles subjected to outdoor weathering for a time period of 6 months. Sample size of eighty-four was determined using the results of the article studying the effects of incorporation of nano oxides on the colour stability of maxillofacial silicone elastomer subjected to outdoor weathering by R.N Akash et al. in the year 2015 [(Akash and Guttal, 2015). The samples were divided into three groups. Control group comprised of 14, maxillofacial silicone elastomer without nano particles, the second group, ZnO2 consisted of 14, maxillofacial silicone elastomer containing 2 % zinc oxide nano particles and the third group ZrSiO2 included 14, maxillofacial silicone elastomer containing 1.5 % zirconium silicate nano particles. 14 samples were prepared as the same sample was used to test both hardness and tear strength. ResultsThe hardness values for maxillofacial silicone in group 3 (with zirconium silicate) was found to be 38.74 which was the lowest in comparison to control and zinc oxide groups. The tear strength of silicone specimens with 1.5 % zirconium silicate it was found to be 5.37 kN/m, which was the highest in comparison to the zinc oxide and the control groups. ConclusionsThe difference in mean hardness and mean tear strength of silicone elastomer with 1.5 % zirconium silicate was found to be, statistically significant. This study suggests that, even after being exposed to the effects of natural weathering, zirconium silicate nano particles may keep the tear strength and hardness of medical grade maxillofacial silicone elastomer up to acceptable ISO criteria.