title: Material properties of a maxillofacial chlorinated polyethylene elastomer stored in simulated skin secretions.
abstract: BACKGROUND
  Facial prostheses deteriorate in a service environment primary due to exposition to various environmental factors, including sebaceous oils (sebum) and perspiration.
  
  
  OBJECTIVE
  This study investigated the physical properties of an experimental, facial prosthetic after immersion for 6 months in simulated sebum, and perspiration at 37 degrees C.
  
  
  METHODS
  Chlorinated polyethylene (CPE) specimens were immersed in simulated perspiration as well as in sebum. Compression tests were conducted on a Zwick testing machine. Shore A hardness measurements were carried out in a CV digital Shore A durometer. Melting and glass transition temperatures were evaluated with a differential scanning calorimeter. Weight changes were measured and color changes were determined in the CIE LAB system using a MiniScan XE spectrophotometer. Simple mathematical models were developed to correlate the measured properties with immersion time. The data were also subjected to analyses of variance (ANOVA) and the Tukey multiple range tests at a level of alpha = 0.05.
  
  
  RESULTS
  Specimens immersed in perspiration became harder due to facilitation of the propagation of cross-linking reaction that probably occurred during aging of the CPE samples. Some weight increase was observed for the specimens immersed into the aqueous solutions, whereas for those immersed in sebum, weight loss was recorded, probably because of extraction of some compounds. The color change was higher for the specimens immersed in sebum than that corresponding to simulated perspiration.
  
  
  CONCLUSIONS
  The chlorinated polyethylene specimens aged for a period, which simulates 1.5 years of clinical service1, showed significant deformations in their physical properties.
authors.affiliation: Department of Chemical Engineering, National Technical University of Athens, 15780 Athens, Greece.
authors.forename: Panagiota N
authors.initials: PN
authors.lastname: Eleni
authors.affiliation: Department of Chemical Engineering, National Technical University of Athens, 15780 Athens, Greece.
authors.forename: Magdalini K
authors.initials: MK
authors.lastname: Krokida
authors.affiliation: Division of Removable Prosthodontics, University of Athens, 11527 Athens, Greece.
authors.forename: Gregory L
authors.initials: GL
authors.lastname: Polyzois
authors.affiliation: Department of Diagnostic Sciences, Prosthodontics, Restorative Dentistry, School of Dentistry, University of Louisville, Louisville, Kentucky 40292-0001.
authors.forename: Lawrence
authors.initials: L
authors.lastname: Gettleman
mesh_terms: D000042:Absorption; D000143:Acids; D000465:Algorithms; D000468:Alkalies; D000704:Analysis of Variance; D002152:Calorimetry, Differential Scanning; D003116:Color; D020724:Elastomers / Q000032:analysis*; D006245:Hardness Tests; D008422:Materials Testing; D008447:Maxillofacial Prosthesis; D015233:Models, Statistical; D011095:Polyethylenes / Q000737:chemistry*; D012629:Sebum / Q000737:chemistry; D012867:Skin / Q000737:chemistry*; D013542:Sweat / Q000737:chemistry; D013696:Temperature
chemical_list: D000143:Acids; D000468:Alkalies; D020724:Elastomers; D011095:Polyethylenes