title: Casting made simple using modified sprue design: an in vitro study.
abstract: BACKGROUND
  Success in dental casting restorations for fixed partial dentures (FPDs) depends on the castability. Castability is described as the ability of an alloy to faithfully reproduce sharp detail and fine margins of a wax pattern. The goal of a prosthodontist is to provide the patient with restorations that fit precisely. Regardless of the alloy used for casting, the casting technique should yield a casted alloy, which should possess sufficient mass, surface hardness and minimal porosity after casting.
  
  
  METHODS
  Twenty patterns for casting were made from three-dimensional printed resin pattern simulating a 3 unit FPD and casted using modified sprue technique. Later test samples were cemented sequentially on stainless steel model using pressure indicating paste and evaluated for vertical marginal gap in eight predetermined reference areas. Marginal gap were measured in microns using Video Measuring System (VMS2010F-CIP Corporation, Korea). A portion of the axial wall of the cast abutments depicting premolar and molar were sectioned and embedded in acrylic resin and tested for micro hardness using Reichert Polyvar 2 Met Microhardness tester (Reichert, Austria) and porosity using Quantimet Image Analyzer (Quantimet Corporation London, England).
  
  
  RESULTS
  The results obtained for marginal gap, micro hardness, and porosity of all test samples were tabulated, descriptive statistics were calculated and the values were found to be within the clinically acceptable range.
  
  
  CONCLUSIONS
  The new sprue technique can be an alternative and convenient method for casting which would minimize metal wasting and less time consuming. However, further studies with same technique on various parameters are to be conducted for its broad acceptance.
authors.affiliation: Department of Prosthodontics, Thai Moogambiga Dental College and Hospitals, Chennai, Tamil Nadu, India.
authors.forename: B Eswaran
authors.initials: BE
authors.lastname: Baskaran
authors.forename: K R
authors.initials: KR
authors.lastname: Geetha Prabhu
authors.forename: R
authors.initials: R
authors.lastname: Prabhu
authors.forename: G Phani
authors.initials: GP
authors.lastname: Krishna
authors.forename: M A
authors.initials: MA
authors.lastname: Eswaran
authors.forename: B
authors.initials: B
authors.lastname: Gajapathi
mesh_terms: D003734:Dental Casting Investment; D003735:Dental Casting Technique; D066298:In Vitro Techniques
chemical_list: D003734:Dental Casting Investment