title: Performance of fast-setting impression materials in the reproduction of subgingival tooth surfaces without soft tissue retraction.
abstract: OBJECTIVE
  Fast-setting impression materials may be prone to inaccuracies due to accidental divergence from the recommended mixing protocol. This prospective randomized clinical trial aimed to assess three-dimensional (3D) deviations in the reproduction of subgingival tooth surfaces and to determine the effect of either following or purposely diverging from the recommended mixing procedure for a fast-setting addition-curing silicone (AS) and fast-setting polyether (PE).
  
  
  METHODS
  After three impressions each were taken from 96 participants, sawcut gypsum casts were fabricated with a standardized procedure and then optically digitized. Data were assessed with a computer-aided 3D analysis.
  
  
  RESULTS
  For AS impressions, multivariate analysis of variance revealed a significant influence of the individual tooth and the degree to which the recommended mixing protocol was violated. For PE impressions, the ambient air temperature and individual tooth showed significant effects, while divergence from the recommended mixing protocol was not of significance.
  
  
  CONCLUSIONS
  The fast-setting PE material was not affected by changes in the recommended mixing protocol. For the two fast-setting materials examined, no divergences from the recommended mixing protocol of less than 2 minutes led to failures in the reproduction of the subgingival tooth surfaces.
authors.forename: Heike
authors.initials: H
authors.lastname: Rudolph
authors.forename: Andreas
authors.initials: A
authors.lastname: Röhl
authors.forename: Michael H
authors.initials: MH
authors.lastname: Walter
authors.forename: Ralph G
authors.initials: RG
authors.lastname: Luthardt
authors.forename: Sebastian
authors.initials: S
authors.lastname: Quaas
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001641:Bicuspid / Q000033:anatomy & histology; D002133:Calcium Sulfate / Q000737:chemistry; D003760:Dental Impression Materials / Q000737:chemistry*; D003761:Dental Impression Technique; D003764:Dental Materials / Q000737:chemistry; D060745:Gingival Retraction Techniques; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D021621:Imaging, Three-Dimensional / Q000379:methods; D008422:Materials Testing; D008875:Middle Aged; D003765:Models, Dental; D008963:Molar / Q000033:anatomy & histology; D011145:Polyvinyls / Q000737:chemistry; D011446:Prospective Studies; D012117:Resins, Synthetic / Q000737:chemistry; D012833:Siloxanes / Q000737:chemistry; D013499:Surface Properties; D013696:Temperature; D013997:Time Factors; D014070:Tooth / Q000033:anatomy & histology*; D055815:Young Adult
chemical_list: D003760:Dental Impression Materials; D003764:Dental Materials; C022821:Impregum; D011145:Polyvinyls; D012117:Resins, Synthetic; D012833:Siloxanes; C480691:aquasil; D002133:Calcium Sulfate