title: The effect of processing methods and acrylic resins on the accuracy of maxillary dentures and toothless denture bases: an in vitro study.
abstract: OBJECTIVE
  To compare the dimensional changes of two autopolymerising denture base resins using three different processing techniques.
  
  
  METHODS
  Sixty edentulous denture bases were made from the polymethylmethacrylates FuturaGen and PalaXpress. Ten bases were made from each resin using a manual injection technique (MI), a pneumatic injection technique (PI), and the fluid resin technique (F). Posterior palatal gap widths between casts and denture bases were measured. For an additional three-dimensional examination of occlusal changes, 10 maxillary dentures were made using FuturaGen/MI and 10 using PalaXpress/PI. Intermolar widths and changes in vertical dimension were determined. In all groups, measurements were taken after polymerization, after removal and repositioning, after polishing, and after storage in water for 1 and 3 weeks. Data were analyzed by using two-way ANOVA and Tukey test (P < .05).
  
  
  RESULTS
  There were no differences in dimensional changes of FuturaGen and PalaXpress specimens. The pneumatic injection system produced significantly smaller posterior palatal gaps after storage in water for 3 weeks compared to the manual injection system (P < .0005) and the fluid resin technique (P = .003). The posterior gaps of dentures were ⋜ 0.04 mm and below the recommended depth for carving a posterior palatal seal (0.4 to 3.0 mm).
  
  
  CONCLUSIONS
  The processing technique rather than the choice of the two resins seems to be the dominate variable with respect to dimensional changes.
authors.affiliation: Department of Prosthodontics, Universitätsklinikum Carl Gustav Carus Dresden, Dresden, Germany.
authors.forename: Henrike
authors.initials: H
authors.lastname: Venus
authors.forename: Klaus
authors.initials: K
authors.lastname: Boening
authors.forename: Ingrid
authors.initials: I
authors.lastname: Peroz
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry*; D000704:Analysis of Variance; D060326:Chemistry Techniques, Synthetic; D003725:Dental Articulators; D003819:Denture Bases; D003779:Denture Design / Q000379:methods; D003827:Denture, Complete, Upper; D006801:Humans; D021621:Imaging, Three-Dimensional; D008422:Materials Testing; D003765:Models, Dental; D058105:Polymerization; D015203:Reproducibility of Results; D018709:Statistics, Nonparametric; D014716:Vertical Dimension
chemical_list: D000180:Acrylic Resins