Mechanical properties of experimental silicone soft lining materials

Abstract

The purpose of this study was to evaluate the mechanical properties of experimental silicone elastomers, Silastic ® MDX 4-4210 reinforced with silica fillers, to assess its potential as a denture soft lining material. The mechanical properties measured included tensile strength, percentage elongation, tear strength, and Shore A hardness. Using one-way ANOVA and Tukey's HSD test, the results indicated that silicone elastomers with filler loadings of 6, 8, and 10 phr had significantly greater tensile strength, percentage elongation, tear strength with a softer surface compared with commercial materials (p<0.001). In conclusion, the experimental silicone elastomers revealed acceptable mechanical properties to be used as denture soft lining materials.

Long-Term Soft Denture Lining Materials

“…The mechanical properties of silicone materials without fillers are generally insufficient for most applications; thus, fillers such as nanoscale amorphous fumed silica are commonly used. The application of properly surface-treated silica fillers, with concentrations of up to few dozen percent, results in the formation of bonds between the filler and the silicone polymer and increases the hardness and strength [10]. In some studies, silica fillers have been experimentally incorporated into LTSDLs to enhance their mechanical properties.…”

“…In some studies, silica fillers have been experimentally incorporated into LTSDLs to enhance their mechanical properties. However, at the laboratory level, it is difficult to obtain a homogenous dispersion of filler without aggregations [10], which can reduce the expected effects of the filler addition. Commercially used mixing machines use vacuum and high shear action to improve the incorporation of fillers into high-viscosity materials and to allow trapped air and large aggregations to be eliminated [8].…”

“…Although the longevity of SLTSDLs was confirmed under clinical conditions, the presence of discoloration and odor was frequently reported among tobacco smokers [7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,31]. Moreover, a gradual increase in the number of fungal colonies on the surfaces of the linings was observed during the first year of use, along with slight discoloration in non-smokers and the local debondings of LTSDLs from the denture base [32].…”

“…The use of LTSDLs will facilitate their adaptation to new dentures [23] and improve the process of rehabilitation, which should be reflected by fewer potential denture corrections and a resulting decrease in treatment costs. Thus, LTSDLs constitute a prospective group of dental materials, and previously reported clinical problems with LTSDLs [7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,31,32] justify further research aimed at improving their properties.…”

“…Santawisuk et al [10] investigated addition-cured, medical-grade RTV silicone with 15%–40% trimethylated silica after the incorporation of 2% to 10% of the hydrophobic filler AEROSIL ® R 812S (Degussa, Cheshire, UK); the results revealed a significant and gradual increase in Shore A hardness and in the other mechanical properties mentioned below; however, the viscosity was acceptable to a concentration of 6% of the new filler.…”