title: Comparison of the Effect of Different Ceramic Alloys and Porcelain Systems upon the Color of Metal-Ceramic Restorations: An In Vitro Study.
abstract: The exact replication of natural tooth color in a metal ceramic restoration is a challenging fact as its affected by enumerable factors. Research revealing the influence of base metal alloys with different porcelain systems on the color of the restorations have shown minimal interest. The aim of the study was to evaluate the optical influence of different alloys (mainly base metal) and ceramic systems affecting the final color of metal-ceramic restorations. Four commercial ceramic alloys, two Ni-Cr, one Co-Cr and a high-noble alloy were combined with two porcelains in metal-ceramic specimens with a standardized thickness of layers. Ten disc-shaped specimens were prepared for each alloy/porcelain combination. High-noble was used as control group. Only opaque and dentin layers were applied. The specimens were analysed with Spectrophotometer, and data were obtained in the CIELAB color system. The recorded data were analysed with a one-way ANOVA and multiple range test by tukey-HSD procedure to identify the significant groups at 5 % level. The final color of the metal-ceramic specimens were significantly affected by both type of the alloy and the porcelain systems used (P < 0.0001). The Co-Cr alloy-porcelain combination produced least color difference when compared with the high-noble control group. There was significant difference (P < 0.0001) between both the brands of Ni-Cr alloy-porcelain systems. For all the alloy-porcelain combinations VMK 95 porcelain showed minimum color difference compared to the d-SIGN porcelain group.
  
  
  CONCLUSIONS
  The final color of metal ceramic specimens was influenced both from the type of base metal alloy substructure and from the type of overlying porcelain.
authors.affiliation: Department of Prosthodontics, SRM Dental College, Ramapuram, Chennai, India ; Flat F-1 76/110 Bajanai Koil Street, Choolaimedu, Chennai, India.
authors.forename: K V
authors.initials: KV
authors.lastname: Anitha
authors.affiliation: Department of Prosthodontics, Saveetha Dental College, Chennai, India.
authors.forename: M
authors.initials: M
authors.lastname: Dhanraj
authors.affiliation: Department of Prosthodontics, Sathyabama Dental College, Chennai, India.
authors.forename: R
authors.initials: R
authors.lastname: Haribabu
keywords: CIE lab; Ceramic alloys; Color matching; Metal–ceramic restorations