title: A clinical comparison of cordless and conventional displacement systems regarding clinical performance and impression quality.
abstract: BACKGROUND
  It is not clear whether newly introduced cordless displacement systems are better able to manage gingiva than conventional systems.
  
  
  OBJECTIVE
  The purpose of this in vivo study was to evaluate the gingival management ability of 4 different displacement methods with a standardized subgingival preparation finish line.
  
  
  METHODS
  The effects of 4 displacement techniques on gingival management and impression quality were evaluated by means of 6 evaluation criteria. A subgingival preparation finish line of between 1 and 2 mm was ensured, and the buccal aspects of 252 (n=63) teeth were clinically assessed for ease of application, time spent, bleeding, remnants, and dilatation. The complete reproduction of the preparation finish line and the bubble and void formations on polyether impressions were also evaluated. The data were statistically analyzed with the χ(2) test (α=.05). The Bonferroni correction was used to control Type I error for the pairwise comparison groups (α=.008).
  
  
  RESULTS
  Statistically significant differences were found for all criteria among the groups (P<.05). The nonimpregnated displacement cord group was the least effective group in terms of bleeding and impression quality (P<.008). The aluminum chloride impregnated cord group and the displacement paste with cap group were found to be comparable in terms of remnants, dilatation, and impression quality (P>.008). The retraction cap with paste group showed better results for ease of application, time spent, and bleeding than the aluminum chloride impregnated cord group (P<.008). Although the group with aluminum chloride impregnated cord, displacement paste, and cap showed better results for dilatation, it was time consuming and difficult (P<.008).
  
  
  CONCLUSIONS
  Except for the nonimpregnated cord group, all of the groups were comparable and clinically useful, with perfect or acceptable impression qualities.
authors.affiliation: Research Fellow, Faculty of Dentistry, Department of Prosthetics, Baskent University, Ankara, Turkey.. Electronic address: zlemacr@gmail.com.
authors.forename: Özlem
authors.initials: Ö
authors.lastname: Acar
authors.affiliation: Associate Professor, Faculty of Dentistry, Department of Prosthetics, Baskent University, Ankara, Turkey.
authors.forename: Selim
authors.initials: S
authors.lastname: Erkut
authors.affiliation: Assistant Professor, School of Dentistry, Department of Prosthodontics, Baskent University, Adana, Turkey.
authors.forename: Tuncer Burak
authors.initials: TB
authors.lastname: Özçelik
authors.affiliation: Private practice, Ankara, Turkey.
authors.forename: Erdem
authors.initials: E
authors.lastname: Ozdemır
authors.affiliation: Associate Professor, Faculty of Science and Letters, Department of Statistics and Computer Science, Baskent University, Ankara, Turkey.
authors.forename: Mehtap
authors.initials: M
authors.lastname: Akçil
mesh_terms: D000077410:Aluminum Chloride; D017607:Aluminum Compounds / Q000627:therapeutic use; D001252:Astringents / Q000627:therapeutic use; D002712:Chlorides / Q000627:therapeutic use; D003442:Crowns; D003760:Dental Impression Materials / Q000737:chemistry; D003761:Dental Impression Technique / Q000592:standards; D003830:Denture, Partial, Fixed; D004106:Dilatation / Q000379:methods; D004987:Ethers / Q000737:chemistry; D005881:Gingiva / Q000033:anatomy & histology* / Q000187:drug effects; D005884:Gingival Hemorrhage / Q000209:etiology; D060745:Gingival Retraction Techniques / Q000295:instrumentation / Q000592:standards; D006490:Hemostatics / Q000627:therapeutic use; D006801:Humans; D011446:Prospective Studies; D013997:Time Factors; D019231:Tooth Preparation, Prosthodontic / Q000379:methods
chemical_list: D017607:Aluminum Compounds; D001252:Astringents; D002712:Chlorides; D003760:Dental Impression Materials; D004987:Ethers; D006490:Hemostatics; D000077410:Aluminum Chloride