Mechanical Properties and Simulated Aging of Silicone Maxillofacial Elastomers: Advancements in the Past 45 Years

Abstract

It is imperative to overcome the existing variability by establishing unified national or international standards/specifications for maxillofacial prosthetic materials. Standardization organizations or bodies, the scientific community, and academia need to be coordinated to achieve this goal. In the meantime and despite all of these theoretically significant alternatives, clinical practice still faces problems with serviceability of maxillofacial prostheses.

Effect of Aging and Weathering on the Physical Properties of Maxillofacial Silicone Elastomers: A Systematic Review and Meta‐Analysis

“…In addition to these, two articles that evaluated the effect of accelerated aging on the physical properties of MDX‐4‐4210 were included. The tensile strength properties of all the mechanical properties were selected for the meta‐analysis, as this property is most crucial for the clinical serviceability of the prostheses …”

“…The tensile strength properties of all the mechanical properties were selected for the meta-analysis, as this property is most crucial for the clinical serviceability of the prostheses. 45 Figure 4 shows the results for the meta-analysis comparing the effect of outdoor weathering and natural/artificial/ accelerated aging on the tensile strength properties of specific maxillofacial silicone elastomers (MDX-4-4210, A-2186, Techsil S25). The meta-analysis of the five studies together favored the case group, with an effect size of 0.497, 95% confidence interval (CI) between 0.231 and 1.073 (i.e., tensile strength properties of case groups of the abovementioned facial silicone elastomers were affected by outdoor weathering and accelerated aging).…”

Effect of plasma treatment on the peel bond strength between maxillofacial silicones and resins

“…Therefore, artificial aging under simulated conditions is an essential part of an in vitro study that tests prosthetic materials' clinical performances. Light's effects on the aging properties of maxillofacial silicone elastomers have been widely studied, and these studies revealed that sun-associated ultraviolet radiation negatively affects the color stability and ideal physical properties of maxillofacial silicones [33][34][35] . With regard to bond strength between silicone and acrylic resin substructure, studies have revealed that both light and heat cause an increase in aging due to further silicone photo-polymerization and reactions with pendant C=C bonds from reactive free radicals of resin material 36,37) .…”

Maxillofacial prostheses challenges in resource constrained regions

“…However, the principal material of preference has been silicone elastomers [57][58][59][60] Margin deterioration of the prostheses occurs due to cosmetics, adhesives, strong solvents or cleansers used alongside the prostheses causing it to degrade; losing the fine thin edges that seamlessly blends with the anatomic human skin and the extrinsic colouring [51]. Most current materials have a low tear strength and poor wettability [68].…”