Research Article
Effect of Recasted Material Addition on the Quality of
Metal-Ceramic Bond: A Macro-, Micro-, and Nanostudy
Karolina Beer–Lech ,
1
Krzysztof Palka,
2
Anna Skic ,
1
Barbara Surowska,
2
and Krzysztof Golacki
1
1
Department of Mechanical Engineering and Automation, Faculty of Production Engineering,
University of Life Sciences in Lublin, Głe ˛boka Street 28, 20-612 Lublin, Poland
2
Department of Materials Engineering, Faculty of Mechanical Engineering, Lublin University of Technology,
Nadbystrzycka Street 36, 20-618 Lublin, Poland
Correspondence should be addressed to Anna Skic; anna.skic@up.lublin.pl
Received 15 December 2017; Revised 27 February 2018; Accepted 29 March 2018; Published 19 April 2018
Academic Editor: Patrice Berthod
Copyright © 2018 Karolina Beer–Lech et al. is is an open access article distributed under the Creative Commons Attribution
License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is
properly cited.
Using the recasted alloys in dental prosthetics could affect the quality of the metal-ceramic bond. However, scientists, alloys
producers,andprosthetistsarestillofdifferentopinions.epurposeofthisstudywastoestimatetheinfluenceofrecastingofthe
NiCrMo alloy on the metal-ceramic bond quality. e research was carried out on macro-, micro- and nanoscales using the three-
point bending test procedure and hardness tests as well as atomic force microscopy and SEM analyses. e SEM analyses showed
good integrity of the metal-ceramic bond. e τ
b
index of all test samples was greater than 45 MPa. e highest values were
recorded for the samples made of 50% and 100% of a brand new material. SEM analysis made after the bending test confirmed
goodmetal-ceramicbondandexhibitedadhesive-cohesivefracture.elargesthardnessofmetalplateswasfoundforthesamples
containing 50% of the recycled material. Atomic force microscopy studies showed that the alloy containing 50% of the recycled
material was characterized by the highest values of surface roughness parameters.
1. Introduction
e metal-ceramic dentures are still widely used due to good
combination of their durability—high strength of metal
substructures and esthetics of porcelain. ey are also more
economical than implants. Despite great popularity of
precious metal alloys, the nonprecious Co-Cr and Ni-Cr
ones are often used interchangeably because of their good
mechanical properties and low costs.
Despitequestioningtheuseofnickelalloysasbiomaterials,
due to the potential harmful effects on human tissues, nickel-
base alloys are still widely used to manufacture the sub-
structures of ceramic crowns and bridges. ese alloys have
larger elasticity modulus than the gold ones and thus thinner
cross section of the alloy can be used to reduce destruction
of the healthy tooth during crown manufacturing [1].
Moreover, the coefficient of thermal expansion of nickel
alloys is compatible with that of thermal expansion of con-
ventional ceramics that are used to produce dental veneers
which provides a good metal-ceramic bond [2].
e final quality and reliability of partial dentures is
influenced mainly by properties of denture and their design
[3], the casting method [4, 5], and the use of already melted
materials for casting its metal substructures [6]. e practice of
using recasting materials is a very common way to reduce the
cost of prosthetic components manufactured in dental labo-
ratories. However, producer’s and researcher’s points of view
are different in this case. Some manufacturers of dental alloys
permit the use of once melted alloys but not less than the 50%
addition of the brand new material. ey also require that the
material must come from the same batch. Another group of
manufacturers do not allow using remelted material (e.g.,
Heraeus Kulzer Co.) or do not provide any information on
the use of dental alloys obtained from recycling.
Hindawi
Advances in Materials Science and Engineering
Volume 2018, Article ID 3271950, 8 pages
https://doi.org/10.1155/2018/3271950