title: Structural damages of maxillofacial biopolymers under solar aging.
abstract: Additional types of silicone biopolymers are widely used in maxillofacial prosthetics. Therefore, the knowledge of the solar radiation's effect on their structural stability is highly important. Four different industrially synthesized biomaterials were examined, called Episil Europe 1, Europe 2, Europe 3 and Africa 3, which were exposed to solar radiation (UVA, UVB) for eight different time periods (from 8 to 168 h). Structural damages due to irradiation exposure were investigated by mechanical tests (compression) and differential scanning calorimetry (DSC) methods. Simple mathematical models were developed, containing parameters with physical meaning such as maximum stress (sigma(max)), maximum strain (epsilon), elasticity parameter (E), and viscoelastic parameter (p), for the compression test, and melting temperature (T (m)) and Enthalpy in melting point (Heat) for DSC. With increasing irradiation time their maximum stress and strain decreased significantly, and the materials lost their elasticity and molecular stability. A decrement in their melting points and heats was observed as irradiation time was increasing. Finally, experimental results demonstrated that solar radiation has a severe effect on the structural stability of the examined biomaterials.
authors.affiliation: Department of Chemical Engineering, National Technical University of Athens, Zografou Campus, 15780, Athens, Greece. peleni@central.ntua.gr
authors.forename: P N
authors.initials: PN
authors.lastname: Eleni
authors.forename: M K
authors.initials: MK
authors.lastname: Krokida
authors.forename: M J
authors.initials: MJ
authors.lastname: Frangou
authors.forename: G L
authors.initials: GL
authors.lastname: Polyzois
authors.forename: Z B
authors.initials: ZB
authors.lastname: Maroulis
authors.forename: D
authors.initials: D
authors.lastname: Marinos-Kouris
mesh_terms: D001696:Biomechanical Phenomena; D001704:Biopolymers / Q000737:chemistry* / Q000528:radiation effects*; D002152:Calorimetry, Differential Scanning; D019245:Compressive Strength; D004548:Elasticity; D006801:Humans; D008422:Materials Testing; D008447:Maxillofacial Prosthesis / Q000009:adverse effects; D012826:Silicone Elastomers / Q000737:chemistry* / Q000528:radiation effects*; D013472:Sunlight / Q000009:adverse effects; D013816:Thermodynamics; D023822:Tissue Engineering
chemical_list: D001704:Biopolymers; D012826:Silicone Elastomers