title: Bond strengths of porcelain to cobalt-chromium alloys made by casting, milling, and selective laser melting.
abstract: BACKGROUND
  Cobalt-chromium (Co-Cr) alloys have been widely used for metal-ceramic fixed prostheses and can be fabricated using conventionally cast or new computer-aided technology. However, the effect of different manufacturing methods on the metal-ceramic bond strength needs further evaluation.
  
  
  OBJECTIVE
  The purpose of this in vitro study was to evaluate the metal-ceramic bond strength of a Co-Cr alloy made by casting, milling, and selective laser melting (SLM).
  
  
  METHODS
  Co-Cr specimens (25×3×0.5 mm) were prepared using a cast, milled, or SLM method and layered with ceramic (8×3×1.1 mm). Metal-ceramic bond strength was measured by a 3-point bend test according to ISO9693. The area fraction of adherence porcelain (AFAP) was determined by measuring the Si content of the specimens with scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS). The metal-ceramic bond strength and AFAP results were analyzed using 1-way analysis of variance and the Bonferroni post hoc test (α=.05). SEM/EDS and metallurgic microscopy were also used to study the specimens' morphology, elemental composition, and metallurgic structure.
  
  
  RESULTS
  No significant differences (P>.05) were found for the bond strength among cast, milled, and SLM Co-Cr alloys. The milled and SLM groups showed significantly more porcelain adherence than the cast group (P<.001). The surface morphologies and oxidation characters of cast, milled, and SLM Co-Cr alloys were similar, whereas the metallurgic structures were different.
  
  
  CONCLUSIONS
  The bond strength between ceramics and Co-Cr alloys is independent of the manufacturing method. However, milling- and SLM-produced alloys had better porcelain adherence.
authors.affiliation: Resident, Department of Stomatology, Jieyang People's Hospital, Jieyang, PR China.
authors.forename: Jieyin
authors.initials: J
authors.lastname: Li
authors.affiliation: Technical director, Dingyuan Dental Lab, Ltd, Dongguan, PR China.
authors.forename: Chaojie
authors.initials: C
authors.lastname: Chen
authors.affiliation: Resident, Department of Prosthodontics, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, PR China.
authors.forename: Juankun
authors.initials: J
authors.lastname: Liao
authors.affiliation: Resident, Department of Prosthodontics, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, PR China.
authors.forename: Lang
authors.initials: L
authors.lastname: Liu
authors.affiliation: Resident, Department of Prosthodontics, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, PR China.
authors.forename: Xiuhua
authors.initials: X
authors.lastname: Ye
authors.affiliation: Resident, Department of Prosthodontics, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, PR China.
authors.forename: Shiyao
authors.initials: S
authors.lastname: Lin
authors.affiliation: Assistant Professor and Director, Department of Prosthodontics, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, PR China. Electronic address: dutaoye@163.com.
authors.forename: Jiantao
authors.initials: J
authors.lastname: Ye
mesh_terms: D002516:Ceramics / Q000737:chemistry; D002858:Chromium Alloys / Q000737:chemistry*; D001840:Dental Bonding; D003735:Dental Casting Technique; D003776:Dental Porcelain / Q000737:chemistry*; D006801:Humans; D007834:Lasers; D008422:Materials Testing; D055595:Mechanical Phenomena; D016876:Metal Ceramic Alloys / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D018583:Pliability; D013052:Spectrometry, X-Ray Emission; D013314:Stress, Mechanical; D013499:Surface Properties; D013718:Tensile Strength
chemical_list: D002858:Chromium Alloys; D016876:Metal Ceramic Alloys; D003776:Dental Porcelain