title: Effects of radiofrequency glow discharge on impression material surface wettability.
abstract: BACKGROUND
  Argon radiofrequency glow discharge (RGD) may simultaneously sterilize and improve surface wettability of impression materials.
  
  
  OBJECTIVE
  The purpose of this study was to define RGD technical parameters that influence the surface wettability of impression material (optimization phase). Definition of RGD was followed by an assessment of these optimized RGD parameters on the wettability of four impression materials either uncontaminated or contaminated with saliva, compared with conventional liquid disinfection (application phase).
  
  
  METHODS
  For the optimization phase, addition silicone samples were cast against glass with 10 samples per group/parameter (n = 210). Parameters evaluated were duration of exposure, sample shape and angle, position within the RGD chamber, and argon gas delivery pressure. Changes in surface wettability were determined with contact angle measurements. For the application phase, standardized RGD parameters (90 degrees to the plasma flow, flat, 60 seconds, 5 psi) were used on four groups of impression materials with (n = 120 samples, 30 per material) or without (n = 120 samples, 30 per material) prior saliva contamination.
  
  
  RESULTS
  RGD treatment of a polyvinyl siloxane impression material significantly (p < 0.0001) reduced contact angle measurements from 63 +/- 1 to 13 +/- 4 degrees, regardless of the parameter evaluated. For the application phase, results indicated different responses to RGD relative to nontreated controls. With all materials treated with RGD or disinfectant exposure, the finest 20 microns standard line was reproduced at x10 magnification with the American National Standards Institute/American Dental Association Specification 19 test die (Sabri Enterprise, Downers Grove, Ill.; n = 80, 10 samples per group).
  
  
  CONCLUSIONS
  These results suggest RGD selectively alters impression material surface wettability.
authors.affiliation: College of Dentistry, University of Iowa, Iowa City, USA.
authors.forename: R M
authors.initials: RM
authors.lastname: Hesby
authors.forename: C R
authors.initials: CR
authors.lastname: Haganman
authors.forename: C M
authors.initials: CM
authors.lastname: Stanford
mesh_terms: D000704:Analysis of Variance; D001128:Argon; D003760:Dental Impression Materials / Q000737:chemistry*; D004203:Disinfection / Q000379:methods; D004563:Electrochemistry; D006801:Humans; D016014:Linear Models; D008422:Materials Testing; D010636:Phenols / Q000737:chemistry; D011145:Polyvinyls / Q000737:chemistry; D012463:Saliva; D012828:Silicones / Q000737:chemistry; D012833:Siloxanes / Q000737:chemistry; D013242:Sterilization / Q000379:methods; D013499:Surface Properties; D013997:Time Factors; D014867:Water; D017155:Wettability
chemical_list: D003760:Dental Impression Materials; D010636:Phenols; D011145:Polyvinyls; D012828:Silicones; D012833:Siloxanes; C034183:vinyl polysiloxane; D014867:Water; D001128:Argon