title: Evaluation of Surface Roughness and Tensile Strength of Base Metal Alloys Used for Crown and Bridge on Recasting (Recycling).
abstract: BACKGROUND
  Dental casting alloys play a prominent role in the restoration of the partial dentition. Casting alloys have to survive long term in the mouth and also have the combination of structure, molecules, wear resistance and biologic compatibility. According to ADA system casting alloys were divided into three groups (wt%); high noble, Noble and predominantly base metal alloys.
  
  
  OBJECTIVE
  To evaluate the mechanical properties such as tensile strength and surface roughness of the new and recast base metal (nickel-chromium) alloys.
  
  
  METHODS
  Recasting of the base metal alloys derived from sprue and button, to make it reusable has been done. A total of 200 test specimens were fabricated using specially fabricated jig of metal and divided into two groups- 100 specimens of new alloy and 100 specimens of recast alloys, which were tested for tensile strength on universal testing machine and surface roughness on surface roughness tester.
  
  
  RESULTS
  Tensile strength of new alloy showed no statistically significant difference (p-value>0.05) from recast alloy whereas new alloy had statistically significant surface roughness (Maximum and Average surface roughness) difference (p-value<0.01) as compared to recast alloy.
  
  
  CONCLUSIONS
  Within the limitations of the study it is concluded that the tensile strength will not be affected by recasting of nickel-chromium alloy whereas surface roughness increases markedly.
authors.affiliation: Senior Lecturer, Department of Prosthodontics, New Horizon Dental College and Hospital , Bilaspur (CG), India .
authors.forename: Amit
authors.initials: A
authors.lastname: Agrawal
authors.affiliation: Reader, Department of Prosthodontics, New Horizon Dental College and Hospital , Bilaspur (CG), India .
authors.forename: Syed W
authors.initials: SW
authors.lastname: Hashmi
authors.affiliation: Senior Lecturer, Department of Prosthodontics, Maharana pratap Dental College and Hospital , Gwalior (MP), India .
authors.forename: Yogesh
authors.initials: Y
authors.lastname: Rao
authors.affiliation: Post Graduate, Department of Periodontics, Pacific Dental College , Udaipur (RAJ), India .
authors.forename: Akanksha
authors.initials: A
authors.lastname: Garg
keywords: Average surface roughness; Casting, Maximum surface roughness; Nickle-chromium alloys