title: Effect of imaging powder and CAD/CAM stone types on the marginal gap of zirconia crowns.
abstract: OBJECTIVE
  To compare the marginal gap using different types of die stones and titanium dies with and without powders for imaging.
  
  
  METHODS
  A melamine tooth was prepared and scanned using a laboratory 3-shape scanner to mill a polyurethane die, which was duplicated into different stones (Jade, Lean, CEREC) and titanium. Each die was sprayed with imaging powders (NP, IPS, Optispray, Vita) to form 15 groups. Ten of each combination of stone/titanium and imaging powders were used to mill crowns. A light-bodied impression material was injected into the intaglio surface of each crown and placed on the corresponding die. Each crown was removed, and the monophase material was injected to form a monophase die, which was cut into 8 sections. Digital images were captured using a stereomicroscope to measure marginal gap. Scanning electron microscopy was used to determine the particle size and shape of imaging powders and stones.
  
  
  RESULTS
  Marginal gaps ranged from mean (standard deviation) 49.32 to 1.20 micrometers (3.97-42.41 μm). There was no statistical difference (P > .05) in the marginal gap by any combination of stone/titanium and imaging powders. All of the imaging powders had a similar size and rounded shape, whereas the surface of the stones showed different structures.
  
  
  CONCLUSIONS
  When a laboratory 3-shape scanner is used, all imaging powders performed the same for scanning titanium abutments. However, there was no added value related to the use of imaging powder on die stone. It is recommended that the selection of stone for a master cast be based on the hysical properties.
  
  
  CONCLUSIONS
  When a laboratory 3-shape scanner is used, the imaging powder is not required for scanning die stone. Whenever scanning titanium implant abutments, select the least expensive imaging powder.
authors: Tariq F
authors: TF
authors: Alghazzawi
authors: Khalid H
authors: KH
authors: Al-Samadani
authors: Jack
authors: J
authors: Lemons
authors: Perng-Ru
authors: PR
authors: Liu
authors: Milton E
authors: ME
authors: Essig
authors: Alfred A
authors: AA
authors: Bartolucci
authors: Gregg M
authors: GM
authors: Janowski
mesh_terms: D017076:Computer-Aided Design; D003442:Crowns; D000044:Dental Abutments; D003760:Dental Impression Materials; D003761:Dental Impression Technique; D018772:Dental Marginal Adaptation; D006801:Humans; D008855:Microscopy, Electron, Scanning; D010316:Particle Size; D011208:Powders; D014025:Titanium; D015040:Zirconium / Q000627:therapeutic use
chemical_list: D003760:Dental Impression Materials; D011208:Powders; D015040:Zirconium; D014025:Titanium; C028541:zirconium oxide
keywords: Scanner; imaging powder; impression; marginal fit; zirconia