title: The effect of time lapse on the accuracy of two acrylic resins used to assemble an implant framework for soldering.
abstract: BACKGROUND
  There are insufficient data on the accuracy of resin indexing materials for the assembly of implant prostheses in vivo.
  
  
  METHODS
  This in vitro study assessed the fit of an implant framework with the use of 2 common acrylic resins.
  
  
  OBJECTIVE
  A standardized type IV gold alloy cast framework with 3 stainless steel implant replicas secured to 3 premachined gold cylinders placed 200 mm apart using a parallelometer was fabricated on a flat type IV stone model. Wax was placed around the center of each bar section, and a silicone matrix was fabricated to enable the same quantity of material to be used for each assembly. Each bar was sectioned at the center of the matrix, and indices (n=20) were fabricated from Duralay and GC Pattern acrylic resins. The materials were allowed to polymerize for 15 minutes before the assemblies were removed from the model. Frameworks were visually assessed for fit after an additional 15 minutes, after 2 hours, and after 24 hours, using the Sheffield 1-screw test. Observational outcomes are presented indicating visually perceived fit relative to the type of indexing resin.
  
  
  RESULTS
  Both indexing materials were judged to be visually accurate at the 15-minute time interval only.
  
  
  CONCLUSIONS
  Within the limitations of this in vitro study, both resin-indexed implant assemblies were judged visually accurate for fit 15 minutes after polymerization but not at subsequent test intervals.
authors.affiliation: School of Dental Science, Trinity College, Dublin, Ireland.
authors.forename: Therese
authors.initials: T
authors.lastname: McDonnell
authors.forename: Francis
authors.initials: F
authors.lastname: Houston
authors.forename: Declan
authors.initials: D
authors.lastname: Byrne
authors.forename: Catherine
authors.initials: C
authors.lastname: Gorman
authors.forename: Noel
authors.initials: N
authors.lastname: Claffey
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry*; D015921:Dental Implants; D003764:Dental Materials / Q000737:chemistry; D017267:Dental Prosthesis Design; D012994:Dental Soldering; D006047:Gold Alloys / Q000737:chemistry; D006801:Humans; D008422:Materials Testing; D008768:Methylmethacrylates / Q000737:chemistry; D011108:Polymers / Q000737:chemistry; D012826:Silicone Elastomers / Q000737:chemistry; D013193:Stainless Steel / Q000737:chemistry; D013499:Surface Properties; D013997:Time Factors; D014885:Waxes / Q000737:chemistry
chemical_list: D000180:Acrylic Resins; D015921:Dental Implants; D003764:Dental Materials; C082318:GC Pattern Resin; D006047:Gold Alloys; D008768:Methylmethacrylates; D011108:Polymers; D012826:Silicone Elastomers; D014885:Waxes; D013193:Stainless Steel; C034578:Duralay