title: Degradation of silicone rubber causes Provox 2 voice prosthesis malfunctioning.
abstract: OBJECTIVE
  Provox 2 voice prosthesis requires periodic replacement due to biofilm proliferation which causes malfunctioning of the valve. The aim of this study was to show that Provox 2 voice prosthesis malfunctioning is due not only to valve obstruction caused by biofilm but also to the silicone variations.
  
  
  METHODS
  Prospective study on the malfunction of Provox2 voice prostheses.
  
  
  METHODS
  Through photographic and electron microscopic assessment, the authors studied nine Provox 2 voice prostheses, which were removed due to malfunctioning.
  
  
  RESULTS
  Findings revealed that the silicone undergoes a degenerative process, thus causing the surface to become rough, deformed, swollen, and translucent. Furthermore, electron microscopy confirmed the presence of immune system cells and biofilm on the prosthesis surface and their role in creating a structural nonhomogenous structure in the silicone, which is deformed due to the presence of "crests" caused by material degeneration.
  
  
  CONCLUSIONS
  The degenerative process of the silicone seems to be related to the oxygen present in the trachea and esophagus and to the production of oxygen-free radicals on the biofilm's part and the immune system.
authors: Department of Sensory Organs, University "Sapienza" of Rome, Rome, Italy. Electronic address: Massimo.fusconi@libero.it.
authors: Massimo
authors: M
authors: Fusconi
authors: Interdepartmental Centre of Electron Microscopy (C.I.M.E.), and Department of Environmental Sciences, Tuscia University, Viterbo, Italy.
authors: Anna Rita
authors: AR
authors: Taddei
authors: Department of Biotechnology and Medical-Surgical, University "Sapienza" of Rome, Polo Pontino, Italy.
authors: Andrea
authors: A
authors: Gallo
authors: Department of Sensory Organs, University "Sapienza" of Rome, Rome, Italy.
authors: Michela
authors: M
authors: Conte
authors: Department of Sensory Organs, University "Sapienza" of Rome, Rome, Italy.
authors: Armando
authors: A
authors: De Virgilio
authors: Department of Sensory Organs, University "Sapienza" of Rome, Rome, Italy.
authors: Antonio
authors: A
authors: Greco
authors: Department of Sensory Organs, University "Sapienza" of Rome, Rome, Italy.
authors: Vincenza Rita
authors: VR
authors: Lo Vasco
authors: Department of Sensory Organs, University "Sapienza" of Rome, Rome, Italy.
authors: Gian Franco
authors: GF
authors: Macrì
authors: Department of Sensory Organs, University "Sapienza" of Rome, Rome, Italy.
authors: Rocco
authors: R
authors: Roma
authors: Department of DIAEE-SASLAb "Sapienza" of Rome, Rome, Italy.
authors: Fabrizio
authors: F
authors: Volpini
authors: Department of Sensory Organs, University "Sapienza" of Rome, Rome, Italy.
authors: Anna Teresa
authors: AT
authors: Benincasa
authors: Department of Sensory Organs, University "Sapienza" of Rome, Rome, Italy.
authors: Marco
authors: M
authors: De Vincentiis
mesh_terms: D001419:Bacteria / Q000254:growth & development* / Q000276:immunology; D018441:Biofilms / Q000254:growth & development*; D020878:Device Removal; D006801:Humans; D007831:Larynx, Artificial / Q000009:adverse effects*; D008855:Microscopy, Electron, Scanning; D011446:Prospective Studies; D011474:Prosthesis Design; D011475:Prosthesis Failure; D016459:Prosthesis-Related Infections / Q000175:diagnosis / Q000276:immunology / Q000382:microbiology*; D012826:Silicone Elastomers; D013314:Stress, Mechanical; D013499:Surface Properties
chemical_list: D012826:Silicone Elastomers
keywords: Biofilm; Silicone rubber; Voice prosthesis