Objective:Disinfection procedures often cause deterioration in a maxillofacial prosthesis. Color and hardness alterations could lead to a replacement of the prosthesis. Material and Methods:An experimental chlorinated polyethylene (CPE) and a commercial polydimethyl siloxane (PDMS) sample were treated with four different disinfection procedures for a period which simulates 1 year of clinical service. The applied disinfection procedures included microwave exposure and immersion in three solutions, sodium hypochlorite, neutral soap and a commercial disinfecting soap. Shore A hardness (ΔΗ) and color differences (ΔΕ) were determined before and after each procedure. All data were analyzed by Two Way Analysis of Variance (ANOVA) and Tukey's post hoc tests at a level of α=0.05. Results:The samples presented significant alterations in color and hardness after the different disinfection treatments. The color differences (ΔΕ) were at least eye detectable in all cases and clinically unacceptable in most of the cases, with values ranging from 1.51 to 4.15 and from 1.54 to 5.92 for the PDMS and CPE material, respectively. Hardness was decreased after all the disinfection procedures in the PDMS, while for the CPE, a decrement was observed after disinfection with sodium hypochlorite and neutral soap and an increment after microwave exposure and the disinfection with a commercial antimicrobial agent. The PDMS samples presented greater alterations in color and hardness after disinfection with sodium hypochlorite solution, while the microwave exposure caused negligible effects. The CPE samples were affected most after disinfection when treated with neutral soap, and more slightly when disinfected with sodium hypochlorite solution. Conclusions:The disinfection procedures caused alterations in color and hardness of the examined materials. The most suitable disinfection procedure for the PDMS material is microwave exposure, while disinfection with sodium hypochlorite solution is not recommended. The CPE material is suggested to be disinfected with sodium hypochlorite solution and the use of neutral soap is not recommended. Comparing the two materials, the PDMS material is most color stable, while the CPE material presented fewer changes in hardness.

The circular economy action plan involves principles related to food waste reduction and integration of recovered nutrients to the market. In this context, the present study aims to highlight the valuable bioactive components found in tomato processing by-products (carotenoids, phenolic compounds and fatty acids) influenced by industrial pre-treatments, particularly cold break (CB) process at 65–75 °C and hot break (HB) process at 85–95 °C. The fatty acid profile of the tomato seed oil was examined by gas chromatography coupled to mass spectrometry (GC-MS), individual carotenoid and phenolic compositions were determined by high performance liquid chromatography (HPLC) and the viscoelastic properties were evaluated by rheological measurements. The physicochemical properties revealed appropriate characteristics of the tomato seed oil to fit the standards of generally accepted edible oils, for both CB and HB derived samples, however, significant qualitative and quantitative differences were detected in their phenolic composition and carotenoids content. Lycopene (37.43 ± 1.01 mg/100 mL) was a major carotenoid in the examined samples, linoleic acid was the main fatty acid (61.73%) detected in the tomato seed oil and syringic acid appeared to be one of two major phenolic acids detected in the samples of CB process. Our findings extend the boundaries of tomato processing industry by validating that tomato seed oil is a bioactive rich edible oil with additional health benefits, which can be integrated in functional food products.

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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.

Physical weathering is usually responsible for the degradation of maxillofacial prosthetic elastomers and the replacement of prostheses. The purpose of this study was to investigate the effects of outdoor weathering on the physical properties of four nonpigmented facial prosthetics after 1 year of exposure. In addition, simple mathematical models were developed to correlate the measured properties with irradiation time, including parameters with physical meaning. Three different medical-grade polydimethyl siloxanes (PDMSs) and an experimental chlorinated polyethylene (CPE) were examined in this study. The samples were exposed to solar radiation for 1 year in Athens, Greece. Mechanical tests (compression and tensile) were performed using universal-type testing machine, and hardness measurements were performed with a durometer (Shore A). Thermal tests were also performed with a differential scanning calorimeter. Simple mathematical models were developed to describe the examined properties. Changes observed in the properties of examined materials, before and after the exposure, reflected the effect of weathering. More specifically, two of the silicone prosthetics (Elastomer 42, TechSIL 25) seemed to become harder and more brittle, different from the other silicone (M511) sample and the CPE sample, which became softer and more ductile. Moreover mathematical models correlate the measured properties with irradiation time, and their constants indicate that duration of exposure seems to increase the degradation. Significant changes in the mechanical and thermal properties of the examined materials were observed as a result of outdoor weathering. The effect of weathering on samples' properties was introduced through its effect on the mathematical models' parameters.

The effect of UVA-UVB irradiation on the mechanical properties of three different industrial types of polydimethylsiloxane and chlorinated polyethylene samples, used in maxillofacial prostheses, was investigated in this study. Mechanical properties and thermal analysis are commonly used to determine the structural changes and mechanical strength. An aging chamber was used in order to simulate the solar radiation and assess natural aging. Compression and tensile tests were conducted on a Zwick testing machine. Durometer Shore A hardness measurements were carried out in a CV digital Shore A durometer according to ASTM D 2240. Glass transition temperature was evaluated with a differential scanning calorimeter. Simple mathematical models were developed to correlate the measured properties with irradiation time. The effect of UVA-UVB irradiation on compressive behavior affected model parameters. Significant deterioration seems to occur due to irradiation in samples.

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