Evaluation of a new silicone elastomer for maxillofacial prostheses.
OBJECTIVE
Although numerous advances in maxillofacial materials have been made in the past several years, the need for improvement continues. Currently, the most widely used materials are the silicones, especially the room temperature-vulcanizing type. This study compared the physical properties of a new silicone material Cosmesil K10 (Cosmedica Ltd, Cardiff, United Kingdom) with those of MDX4-4210 (Dow Corning Corporation, Midland, MI), a popular material for maxillofacial prostheses.


METHODS
The properties that were investigated were tensile strength, modulus at 100% elongation, percentage of elongation, tear strength, and hardness. The properties tested were selected because of their clinical significance for fabricating maxillofacial prostheses. Tensile strength and elongation were measured with a Monsanto Tensometer (Monsanto Ltd, Swindon, England) and dumbell-shaped specimens according to the International Organization for Standardization (ISO) specification no. 37. The tear test was performed on the Monsanto machine with unnicked 90 degree angle-shaped specimen following the ISO specification no. 34. The type A Shore durometer was used to measure hardness on specimens 25 x 25 x 10 mm according to the American Society for Testing Materials specification no. D2240.


RESULTS
The results showed that MDX4-4210 had a greater tensile strength and modulus (P = .0002; P = .0015). No significant difference (P = .1986) was found for the percentage of elongation between MDX4-4210 and Cosmesil K10. Cosmesil K10 had a greater tear strength and was slightly harder (P = .0022; P = .0421) than MDX4-4210.


CONCLUSIONS
Cosmesil K10 showed physical properties similar to those of MDX4-4210. An improvement in the predictability of the mechanical behavior of Cosmesil K10 would further enhance the value of the material.
Polyzois
G L
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Department of Prosthodontics, Division of Removable Prosthodontics, Maxillofacial Prosthetics Service, School of Dentistry, University of Athens, Greece.
D004548:Elasticity; D005069:Evaluation Studies as Topic; D006244:Hardness; D008422:Materials Testing; D008447:Maxillofacial Prosthesis; D018583:Pliability; D012826:Silicone Elastomers / Q000737:chemistry*; D018709:Statistics, Nonparametric; D013718:Tensile Strength
D012826:Silicone Elastomers