title: An alcohol-free tissue conditioner--a laboratory evaluation.
abstract: OBJECTIVE
  An alcohol-free tissue conditioner based on a n-butyl methacrylate/i-butyl methacrylate copolymer has recently been developed. The purpose of the present study was to compare some key properties of the new tissue conditioner with those of poly(ethyl methacrylate)-based conventional materials containing ethyl alcohol. The effect of a coating, which consisted of poly(ethyl methacrylate) and methyl methacrylate, was also evaluated.
  
  
  METHODS
  The new alcohol-free tissue conditioner (Fictioner) and three tissue conditioners containing ethyl alcohol (FITT, Hydro-Cast, SR-Ivoseal) were evaluated. The coated alcohol-free material was also used. Gelation characteristics, dynamic viscoelastic properties and compatibility with dental stones were measured using a displacement rheometer, dynamic viscoelastometer and profilometer, respectively. In addition, weight changes during immersion in water were determined.
  
  
  RESULTS
  The working time and gelation time of the alcohol-free tissue conditioner were similar to those of the conventional materials. This alcohol-free material had significantly lower shear storage modulus and shear loss modulus, and higher loss tangent (P<0.05) than FITT and SR-Ivoseal at 0.01 and 1 Hz. The alcohol-free material maintained its inherent viscoelastic properties and exhibited only a slight change in weight during 14 days of water immersion when compared to the conventional materials. The application of the coating significantly reduced the loss of the initial viscoelastic properties and surface quality during the test periods.
  
  
  CONCLUSIONS
  The coated alcohol-free tissue conditioner would be superior to the conventional materials containing ethyl alcohol in view of viscoelastic properties after gelation, compatibility with dental stones and durability.
authors.affiliation: Department of Prosthetic Dentistry, Graduate School of Biomedical Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8553, Japan. hmurata@hiroshima-u.ac.jp
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Murata
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Narasaki
authors.forename: Taizo
authors.initials: T
authors.lastname: Hamada
authors.forename: John F
authors.initials: JF
authors.lastname: McCabe
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry*; D000704:Analysis of Variance; D002133:Calcium Sulfate / Q000737:chemistry; D000431:Ethanol / Q000737:chemistry; D008768:Methylmethacrylates / Q000737:chemistry*; D013499:Surface Properties; D013997:Time Factors; D014016:Tissue Conditioning, Dental / Q000379:methods*
chemical_list: D000180:Acrylic Resins; D008768:Methylmethacrylates; C478961:poly(ethylacrylate); D000431:Ethanol; D002133:Calcium Sulfate