title: Evaluation of marginal gap of Ni-Cr copings made with conventional and accelerated casting techniques.
abstract: BACKGROUND
  Conventional casting techniques following the manufacturers' recommendations are time consuming. Accelerated casting techniques have been reported, but their accuracy with base metal alloys has not been adequately studied.
  
  
  OBJECTIVE
  We measured the vertical marginal gap of nickel-chromium copings made by conventional and accelerated casting techniques and determined the clinical acceptability of the cast copings in this study.
  
  
  METHODS
  Experimental design, in vitro study, lab settings.
  
  
  METHODS
  Ten copings each were cast by conventional and accelerated casting techniques. All copings were identical, only their mold preparation schedules differed. Microscopic measurements were recorded at ×80 magnification on the perpendicular to the axial wall at four predetermined sites. The marginal gap values were evaluated by paired t test.
  
  
  RESULTS
  The mean marginal gap by conventional technique (34.02 μm) is approximately 10 μm lesser than that of accelerated casting technique (44.62 μm). As the P value is less than 0.0001, there is highly significant difference between the two techniques with regard to vertical marginal gap.
  
  
  CONCLUSIONS
  The accelerated casting technique is time saving and the marginal gap measured was within the clinically acceptable limits and could be an alternative to time-consuming conventional techniques.
authors.affiliation: Department of Prosthodontics, Narayana Dental College, Nellore, Andhra Pradesh, India.
authors.forename: Pavan Kumar
authors.initials: PK
authors.lastname: Tannamala
authors.forename: Nagarasampatti Sivaprakasam
authors.initials: NS
authors.lastname: Azhagarasan
authors.forename: K Chitra
authors.initials: KC
authors.lastname: Shankar
mesh_terms: D002858:Chromium Alloys / Q000737:chemistry*; D003734:Dental Casting Investment / Q000737:chemistry*; D003735:Dental Casting Technique / Q000295:instrumentation / Q000592:standards*; D018772:Dental Marginal Adaptation / Q000592:standards*; D006801:Humans; D008422:Materials Testing; D013193:Stainless Steel / Q000737:chemistry; D013499:Surface Properties; D019231:Tooth Preparation, Prosthodontic; D014885:Waxes / Q000737:chemistry
chemical_list: D002858:Chromium Alloys; D003734:Dental Casting Investment; D014885:Waxes; D013193:Stainless Steel