title: Identifying the Optimal Water-Occluding Earplugs: A Scientific Simulation Study.
abstract: OBJECTIVE
  Numerous types of water-occluding earplugs are available as a means of preventing infection in patients with external and middle ear disease. However, little is known about the comparative efficacies of these earplugs with prolonged water exposure. In this study, we assessed the water impermeability of various earplug materials to prolonged water exposure.
  
  
  METHODS
  Nine earplugs were tested: cotton wool mixed with petroleum jelly, cotton wool externally coated with petroleum jelly, Blu-Tack, foam earplugs, silicone putty, silicone earplugs, flanged earplugs, and hard and soft silicone custom-moulds. Precision-engineered cups were filled with 30 mL water and sealed with lids that contained a 10 mm diameter hole to simulate the ear canal. The aperture was occluded with different earplugs, and the cup was inverted. Computer software was used to record the water loss to the nearest 10 milligrams 720 times over a three-hour period. The test was repeated five times for each material.
  
  
  RESULTS
  The water permeability onset, rate, and total amount of water loss varied markedly between the materials; cotton wool mixed with petroleum jelly demonstrated the fastest onset of leak and the highest rate of water loss (p < 0.00001), as well as the largest amount of cumulative water loss (p = 0.00213). The soft silicone custom-mould plugs, hard silicone custom-mould plugs, foam plugs, and silicone putty demonstrated no leaks.
  
  
  CONCLUSIONS
  This study demonstrates a wide range of water permeabilities of commonly used ear-occluding materials during prolonged water exposure. We found that the generally suggested regimen of cotton wool mixed with petroleum jelly may be inefficacious for substantial periods of water exposure.
authors.affiliation: Department of Otolaryngology, Head and Neck Surgery, Princess of Wales Hospital, Bridgend, United Kingdom. alialhussaini@doctors.org.uk.
authors.forename: Joshua
authors.initials: J
authors.lastname: Kovoor
authors.forename: Ali
authors.initials: A
authors.lastname: Al Hussaini
authors.forename: Steven
authors.initials: S
authors.lastname: Backhouse
mesh_terms: D004430:Ear Protective Devices; D004867:Equipment Design; D004868:Equipment Failure; D006801:Humans; D008422:Materials Testing; D008954:Models, Biological; D010539:Permeability; D013499:Surface Properties; D014867:Water
chemical_list: D014867:Water