title: Disinfection procedures: their efficacy and effect on dimensional accuracy and surface quality of an irreversible hydrocolloid impression material.
abstract: OBJECTIVE
  This study investigated the antibacterial efficacy and effect of 0.55% ortho-phthalaldehyde (Cidex OPA(®)) and 0.5% sodium hypochlorite (NaOCl) on the dimensional accuracy and surface quality of gypsum casts retrieved from an irreversible hydrocolloid impression material.
  
  
  METHODS
  A simulated clinical cast and technique was developed to compare the dimensional accuracy and surface quality changes of the test gypsum casts with controls. Dimensional accuracy measurements were completed between fixed points using a travelling microscope under low angle illumination at a magnification of ×3. Surface quality changes of "smooth" and "rough" areas on the cast were evaluated by means of optical profilometry. The efficacy of the disinfection procedures against Pseudomonas aeruginosa was evaluated by determining the number of colony forming units (cfu) recovered after disinfection of alginate discs inoculated with 1×10⁶cfu for defined intervals.
  
  
  RESULTS
  The dimensional accuracy of the gypsum casts was not significantly affected by the disinfection protocols. Neither disinfectant solution nor immersion time had an effect on the surface roughness of the "smooth" area on the cast, however, a significant increase in surface roughness was observed with increasing immersion time for the "rough" surface. Complete elimination of viable Pseudomonas aeruginosa cells from alginate discs was obtained after 30 and 120 s immersion in Cidex OPA(®) and NaOCl, respectively.
  
  
  CONCLUSIONS
  Immersion of irreversible hydrocolloid impressions in Cidex OPA(®) for 30 s was proved to be the most effective disinfection procedure.
authors.affiliation: Division of Restorative Dentistry and Periodontology, Dublin Dental University Hospital, University of Dublin, Trinity College Dublin, Dublin 2, Ireland.
authors.forename: A
authors.initials: A
authors.lastname: Rentzia
authors.forename: D C
authors.initials: DC
authors.lastname: Coleman
authors.forename: M J
authors.initials: MJ
authors.lastname: O'Donnell
authors.forename: A H
authors.initials: AH
authors.lastname: Dowling
authors.forename: M
authors.initials: M
authors.lastname: O'Sullivan
mesh_terms: D000464:Alginates / Q000737:chemistry; D058491:Bacterial Load; D002133:Calcium Sulfate / Q000737:chemistry; D003102:Colloids / Q000737:chemistry*; D019551:Dental Disinfectants / Q000737:chemistry* / Q000494:pharmacology; D003760:Dental Impression Materials / Q000737:chemistry*; D003761:Dental Impression Technique / Q000295:instrumentation; D003764:Dental Materials / Q000737:chemistry; D004203:Disinfection / Q000379:methods*; D006801:Humans; D007101:Immersion; D008422:Materials Testing; D003765:Models, Dental; D011550:Pseudomonas aeruginosa / Q000187:drug effects; D012973:Sodium Hypochlorite / Q000737:chemistry; D013499:Surface Properties; D013997:Time Factors; D009764:o-Phthalaldehyde / Q000737:chemistry
chemical_list: D000464:Alginates; D003102:Colloids; D019551:Dental Disinfectants; D003760:Dental Impression Materials; D003764:Dental Materials; D009764:o-Phthalaldehyde; D012973:Sodium Hypochlorite; D002133:Calcium Sulfate