Journal of Prosthetic Dentistry
Research and Education|Articles in Press

Effects of posttreatment on metal-ceramic bond properties of selective laser melted Co-Cr dental alloy. Part 1: Annealing temperature

Published:February 24, 2023DOI:


      Statement of problem

      Dental cobalt-chromium (Co-Cr) alloy manufactured by selective laser melting (SLM) is not recommended for clinical applications before annealing because of excessive residual stress. However, limited information is available regarding the relationship between annealing temperature and the metal-ceramic bond properties of SLM Co-Cr alloys.


      The purpose of this in vitro study was to investigate the effects of annealing temperature on the metal-ceramic bond properties of SLM Co-Cr alloys.

      Material and methods

      Four groups with different annealing temperatures (850 °C; 950 °C; 1050 °C; 1150 °C) were prepared by using SLM techniques. Bond strengths were measured by using a 3-point bend test; subsequently, debonded surface morphologies and elements were assessed by using a scanning electron microscopy (SEM) coupled with energy-dispersive X-ray spectroscopy (EDS). The area fraction of adherence porcelain (AFAP) value was introduced to analyze fracture characteristics. Microstructural and interfacial characteristics were characterized by SEM/EDS and X-ray diffraction analysis. The coefficient of thermal expansion (CTE) test was used to analyze thermal matching. A 1-way ANOVA and the Tukey honestly significant difference tests were used to analyze bond strengths and AFAP values statistically (α=.05).


      The mean ±standard deviation values of the metal-ceramic bond strengths were 40.68 ±4.34 MPa for the 850 °C group, 37.54 ±5.34 MPa for the 950 °C group, 45.97 ±2.18 MPa for the 1050 °C group, and 50.79 ±1.79 MPa for the 1150 °C group. Significant differences (P<.05) were observed among all groups. Debonded surfaces and AFAP analysis displayed a mixed fracture mode of adhesive and cohesive fracture, and 1150 °C-annealing specimens exhibited better fracture characteristics close to cohesive fractures. As the temperature increased, native oxide film thicknesses remained unchanged; the 850 °C group had the thinnest diffusion layer, while the other 3 groups had similar thicknesses. Although the 1050 °C and 1150 °C groups displayed higher CTE values, their microstructures were more conducive to atomic diffusion and improved chemical bonding. Microstructure analysis found that ε phase and second-phase precipitates jointly affected metal-ceramic bond strength.


      Annealing temperatures affected the metal-ceramic bond strengths of SLM Co-Cr porcelain specimens. 1150 °C annealing SLM Co-Cr specimens displayed higher bond strengths and improved fracture and interface characteristics among the 4 groups.
      To read this article in full you will need to make a payment

      Purchase one-time access:

      Academic & Personal: 24 hour online accessCorporate R&D Professionals: 24 hour online access
      One-time access price info
      • For academic or personal research use, select 'Academic and Personal'
      • For corporate R&D use, select 'Corporate R&D Professionals'


      Subscribe to Journal of Prosthetic Dentistry
      Already a print subscriber? Claim online access
      Already an online subscriber? Sign in
      Institutional Access: Sign in to ScienceDirect


        • Al Jabbari Y.S.
        • Koutsoukis T.
        • Barmpagadaki X.
        • Zinelis S.
        Metallurgical and interfacial characterization of PFM Co–Cr dental alloys fabricated via casting, milling or selective laser melting.
        Dent Mater. 2014; 30: 79-88
        • Hedberg Y.S.
        • Qian B.
        • Shen Z.
        • Virtanen S.
        • Wallinder I.O.
        In vitro biocompatibility of CoCrMo dental alloys fabricated by selective laser melting.
        Dent Mater. 2014; 30: 525-534
        • Di Fiore A.
        • Savio G.
        • Stellini E.
        • Vigolo P.
        • Monaco C.
        • Meneghello R.
        Influence of ceramic firing on marginal gap accuracy and metal-ceramic bond strength of 3D-printed Co-Cr frameworks.
        J Prosthet Dent. 2020; 124: 75-80
        • Leon M.R.
        • Husain N.A.H.
        • Methani M.M.
        • Ozcan M.
        Chemical composition, surface roughness, and ceramic bond strength of additively manufactured cobalt-chromium dental alloys.
        J Prosthet Dent. 2021; 125: 825-831
        • Wang H.
        • Feng Q.
        • Li N.
        • Xu S.
        Evaluation of metal-ceramic bond characteristics of three dental Co-Cr alloys prepared with different fabrication techniques.
        J Prosthet Dent. 2016; 116: 916-923
        • Wei W.
        • Zhou Y.
        • Liu W.
        • Li N.
        • Yan J.
        • Li H.
        Microstructural characterization, mechanical properties, and corrosion resistance of dental Co-Cr-Mo-W alloys manufactured by selective laser melting.
        J Mater Eng Perform. 2018; 27: 5312-5320
        • Zhou Y.
        • Li N.
        • Yan J.
        • Zeng Q.
        Comparative analysis of the microstructures and mechanical properties of Co-Cr dental alloys fabricated by different methods.
        J Prosthet Dent. 2018; 120: 617-623
        • Wang L.
        • Jiang X.
        • Zhu Y.
        • Zhu X.
        • Sun J.
        • Yan B.
        An approach to predict the residual stress and distortion during the selective laser melting of AlSi10Mg parts.
        Int J Adv Manuf Tech. 2018; 97: 3535-3546
        • Yadroitsev I.
        • Yadroitsava I.
        Evaluation of residual stress in stainless steel 316L and Ti6Al4V samples produced by selective laser melting.
        Virtual Phys Prototy. 2015; 10: 67-76
        • Mengucci P.
        • Barucca G.
        • Gatto A.
        • et al.
        Effects of thermal treatments on microstructure and mechanical properties of a Co-Cr-Mo-W biomedical alloy produced by laser sintering.
        J Mech Behav Biomed. 2016; 60: 106-117
        • Kajima Y.
        • Takaichi A.
        • Kittikundecha N.
        • et al.
        Effect of heat-treatment temperature on microstructures and mechanical properties of Co-Cr-Mo alloys fabricated by selective laser melting.
        Mat Sci Eng A-Struct. 2018; 726: 21-31
        • Zhou Y.
        • Sun Q.
        • Dong X.
        • et al.
        Microstructure evolution and mechanical properties improvement of selective laser melted Co-Cr biomedical alloys during subsequent heat treatments.
        J Alloy Compd. 2020; 840: 155664
        • Wei W.
        • Zhou Y.
        • Sun Q.
        • et al.
        Microstructures and mechanical properties of dental Co-Cr-Mo-W alloys fabricated by selective laser melting at different subsequent heat treatment temperatures.
        Metall Mater Trans A. 2020; 51: 3205-3214
        • Yan X.
        • Xu Y.X.
        • Wu Y.
        • Lin H.
        Effects of heat treatment on metal-ceramic combination of selective-laser-melted cobalt-chromium alloy.
        J Prosthet Dent. 2018; 120: 319.e1-319.e6
        • Tulga A.
        Effect of annealing procedure on the bonding of ceramic to cobalt-chromium alloys fabricated by rapid prototyping.
        J Prosthet Dent. 2017; 119: 643-649
        • International Organization for Standardization
        ISO 9693-1(E): Dentistry-Compatibility testing-Part 1: Metal-ceramic systems. International Organization for Standardization, Geneva2012.
        (Available at:)
        • International Organization for Standardization
        ISO 22674(E): Dentistry-Metallic materials for fixed and removable restorations and appliances. International Organization for Standardization, Geneva2016.
        (Available at:)
        • Zhou Y.
        • Li N.
        • Wang H.
        • Yan J.
        • Liu W.
        • Xu S.
        Effects of the rare earth element lanthanum on the metal-ceramic bond strength of dental casting Co-Cr alloys.
        J Prosthet Dent. 2019; 121: 848-857
        • Ringle R.D.
        • Mackert J.R.
        • Fairhurst C.W.
        An x-ray spectrometric technique for measuring porcelain-metal adherence.
        J Dent Res. 1983; 62: 933-936
        • Sage M.
        • Gillaud C.
        Méthode d'analyse quantitative des variétés allotropiques du cobalt par les rayons X.
        Rev Metall-Paris. 1950; 49: 139-145
        • Zhou Y.
        • Wei W.
        • Yan J.
        • et al.
        Microstructures and metal-ceramic bond properties of Co-Cr biomedical alloys fabricated by selective laser melting and casting.
        Mat Sci Eng A-Struct. 2019; 759: 594-602
        • Johnson T.
        • Noort R.V.
        • Stokes C.W.
        Surface analysis of porcelain fused to metal systems.
        Dent Mater. 2006; 22: 330-337
        • Anusavice K.J.
        • Horner J.A.
        • Fairhurst C.W.
        Adherence controlling elements in ceramic-metal systems. I. Precious Alloys.
        J Dent Res. 1977; 56: 1045-1052
        • Bagby M.
        • Marshall S.J.
        • Marshall G.W.
        Metal ceramic compatibility: a review of the literature.
        J Prosthet Dent. 1990; 63: 21-25