title: The optical effect of composite luting cement on all ceramic crowns.
abstract: OBJECTIVE
  To investigate the optical properties of resin-based composite cements and assess their effects on the color of all ceramic crowns.
  
  
  METHODS
  Optical properties of three cements (Variolink II, Esthetic, Nexus II) were analyzed using disk samples (100 microm and 1.0 mm diameter) based on CIELAB color coordinates L*a*b*C* and opacity index. Empress (Ivoclar) and Katana (Noritake) crowns were filled with four different shades of die material (IPS die material ST3, ST5, ST9 and Tetric Evo Ceram Bleach XL). The shade of the crowns was measured with each of three shades of composite cement (Chroma, Bleach and Opaque, Esthetic cement). ST3 and glycerin served as the control. Color differences were calculated in incisal, body and cervical regions.
  
  
  RESULTS
  In the cervical and body regions, the color change caused by the bleach abutment could not be altered by using different colored cements for the Empress and Katana crowns. In the cervical region, the color changes effected by the dark brown abutment could be reversed with the bleach luting cement; in the body region this was true only for the Empress crown. Neither different abutment colors nor different luting cement shades resulted in perceptible color changes in the incisal regions. Mean DeltaE* values in the three areas (incisal, body, cervical) were significantly different (p-value<0.01); in the cervical and body regions Empress mean DeltaE* was significantly larger (p<0.01).
  
  
  CONCLUSIONS
  The composite cements evaluated in this study created perceptible color differences with particular combinations of die material, cement and ceramic crown.
authors: Department of Restorative Dentistry and Biomaterials Sciences, Harvard School of Dental Medicine, 188 Longwood Avenue, Boston, MA 02115, USA.
authors: John
authors: J
authors: Chang
authors: John D
authors: JD
authors: Da Silva
authors: Maiko
authors: M
authors: Sakai
authors: Joshua
authors: J
authors: Kristiansen
authors: Shigemi
authors: S
authors: Ishikawa-Nagai
mesh_terms: D003116:Color; D003188:Composite Resins / Q000737:chemistry*; D003442:Crowns; D000044:Dental Abutments; D003764:Dental Materials / Q000737:chemistry; D003776:Dental Porcelain / Q000737:chemistry*; D017267:Dental Prosthesis Design; D006801:Humans; D018020:Lithium Compounds / Q000737:chemistry; D008422:Materials Testing; D055620:Optical Phenomena; D019279:Resin Cements / Q000737:chemistry*; D013053:Spectrophotometry; D013499:Surface Properties; D014070:Tooth / Q000473:pathology; D019231:Tooth Preparation, Prosthodontic; D015040:Zirconium / Q000737:chemistry
chemical_list: D003188:Composite Resins; D003764:Dental Materials; C118557:Empress 2; D018020:Lithium Compounds; C433206:Nexus; D019279:Resin Cements; C501891:Tetric EvoCeram; D003776:Dental Porcelain; C103502:Variolink; D015040:Zirconium; C028541:zirconium oxide