title: Retention of veneered stainless steel crowns on replicated typodont primary incisors: an in vitro study.
abstract: OBJECTIVE
  The purpose of this in vitro study was to determine the effect of crimping and cementation on retention of veneered stainless steel crowns.
  
  
  METHODS
  One hundred twenty crowns, 90 from 3 commercially available brands of veneered stainless steel crowns (Dura Crown, Kinder Krown, and NuSmile Primary Crown) and 30 (plain) Unitek stainless steel crowns were assessed for retention. An orthodontic wire was soldered perpendicular to the incisal edge of the crowns; the crowns were fitted to acrylic replicas of ideal crown preparations and were divided equally into 3 test groups: group 1--crowns were crimped only (no cement used); group 2--crowns were cemented only; and group 3--crowns were crimped and cemented to the acrylic replicas. An Instron machine recorded the amount of force necessary to dislodge the crowns and the results were statistically analyzed using 2-way ANOVA and Tukey honestly significant difference (HSD) test.
  
  
  RESULTS
  Group 3 was statistically more retentive than groups 1 and 2. Group 2 was statistically more retentive than group 1 (P < .001). In group 1, Unitek crowns were statistically more retentive than the veneered crowns (P < .05). In group 2, NuSmile crowns showed statistically less retention values than all other crowns (P < .05). In group 3,Kinder Krown crowns showed statistically better retention rates than all other brands (P < .05).
  
  
  CONCLUSIONS
  Significantly higher retention values were obtained for all brands tested when crimping and cement were combined. The crowns with veneer facings were significantly more retentive than the nonveneered ones when cement and crimping were combined.
authors.affiliation: Department of Dentistry Dentistry, University of Florida, Gainesville, Fla, USA. mguelmann@dental.ufl.edu
authors.forename: Marcio
authors.initials: M
authors.lastname: Guelmann
authors.forename: Daren F
authors.initials: DF
authors.lastname: Gehring
authors.forename: Clara
authors.initials: C
authors.lastname: Turner
mesh_terms: D000704:Analysis of Variance; D017438:Bisphenol A-Glycidyl Methacrylate; D003442:Crowns; D001840:Dental Bonding; D017267:Dental Prosthesis Design; D003799:Dental Stress Analysis; D003801:Dental Veneers; D006801:Humans; D007180:Incisor; D003765:Models, Dental; D011092:Polyethylene Glycols; D011109:Polymethacrylic Acids; D019279:Resin Cements; D013193:Stainless Steel; D018709:Statistics, Nonparametric; D013718:Tensile Strength; D019231:Tooth Preparation, Prosthodontic; D014094:Tooth, Deciduous
chemical_list: D011109:Polymethacrylic Acids; C462240:RelyX ARC; D019279:Resin Cements; D013193:Stainless Steel; D011092:Polyethylene Glycols; D017438:Bisphenol A-Glycidyl Methacrylate