Evaluation of hardness and surface roughness of two maxillofacial silicones following disinfection

Abstract

The purpose of this study was to evaluate the Shore A hardness and surface roughness of two silicones for maxillofacial prosthetic treatment, under the infl uence of chemical disinfection and storage. Twenty-eight specimens were obtained, half of which were made of Silastic MDX 4-4210 silicone and, the other half were made of Silastic 732 RTV silicone. The specimens were divided into four groups: Silastic 732 RTV and MDX 4-4210 with disinfection 3 times a week with Efferdent tablets and the same materials without disinfection. The hardness of the materials was analyzed with a Shore A Durometer. The surface roughness was established by a digital portable roughness tester, initially and 2 months after the confection of the specimens. A variance test was applied (2-way ANOVA), followed by Tukey test (the level of signifi cance was set at 1%). The storage time factor statistically infl uenced (p < 0.01) the materials' properties of hardness and roughness. MDX 4-4210 (28.59 Shore A, 0.789 Ra) presented higher values than Silastic 732 RTV (18.08 Shore A, 0.656 Ra) for both properties. Regarding the disinfection period, there was no signifi cant difference in any of the materials tested.

Color stability of maxillofacial silicone with nanoparticle pigment and opacifier submitted to disinfection and artificial aging

“…5,16,27,28 The silicone Silastic MDX4-4210 Silicone (Dow Corning Corporation, Midland, Michigan) was handled in agreement with the manufacturer's instructions, at a controlled room temperature 23 + 2…”

“…Ten specimens of each group were disinfected with one of the following substances: Efferdent alkaline peroxide effervescent (Ef) tablets (Pfizer Consumer Healthcare, Morris Plains, New Jersey), 5,27,28 neutral soap (Ns) (Johnson & Johnson, São José dos Campos, SP, Brazil), 5,27,28 and 4% solution of chlorhexidine (Cl) (Naturativa, Araçatuba, SP, Brazil). 31,32 The process of chemical disinfection was accomplished three times a week for 60 days.…”

“…31,32 The process of chemical disinfection was accomplished three times a week for 60 days. 5,27,28,32 For disinfection with Efferdent, specimens were immersed for 15 min in a container containing an effervescent tablet dissolved in 250 mL of warm water with an initial temperature of 37…”

“…5,27,28 Specimens washed with neutral soap were thoroughly scrubbed with it by hand friction for 30 s and rinsed in running water. 32 Specimens disinfected with chlorhexidine were immersed in the solution for 10 min and rinsed in running water.…”

Influence of nanoparticles on color stability, microhardness, and flexural strength of acrylic resins specific for ocular prosthesis

“…Similar to the color change results, this result can be explained by the presumably smaller size of TiO 2 compared with ZnO and BaSO 4 , which would promote tight linking to the resin particles and prevent their degradation. 22,44,45 Specification 12 of the American Dental Association states that the surface microhardness of denture base acrylic resin must be at least 15 Knoop. 24,49 As ocular prostheses are subjected to fewer impacts of lower intensity compared with denture bases, the microhardness values found in this study can be considered satisfactory and clinically acceptable.…”