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Author's response
No full textLETTERS TO THE EDITOR
Comments regarding: Lucchetti MC, Fratto G, Valeriani F, De Vittori E, Giampaoli S,
Papetti P, et al. Cobalt-chromium alloys in dentistry: An evaluation of metal
ion release. J Prosthet Dent 2015;114:602-8
Dear Editor:
We read with great interest the recently published article,
“Cobalt-chromium alloys in dentistry: An evaluation of
metal ion release” by Lucchetti et al.1 in which the authors
aimed to investigate metal ion release of Co-Cr
alloy that was manufactured both by direct metal laser
sintering (DMLS) and conventional casting techniques.
The material method of the study is very clear and
detailed for both chemical and biological corrosion. For
this reason we aimed to use this methodology as a
reference in one of our in vitro studies. However, when
we read the article in detail we detected an error in the
given formula of artificial saliva.
In literature, artificial saliva is often used in many
formulas for in vitro studies to simulate in vivo conditions.
2-5 In the Lucchetti et al.1 article, the content of
artificial saliva was formulated as: 2.0.10-2 M KCl, 1.4.10-3
M KH2PO4, and 1.5.10-2 M K2HCO3. The researchers
indicate they used Mutlu-Sagesen et al5 and ISO 10271
standards6 in the material and method as reference.
However, the referenced study of Mutlu-Sagesen et al5
gave the artificial saliva as: 7.69 g of K2HPO4, 2.46 g of
KH2PO4, 5.3 g of NaCl, and 9.3 g of KCl added to 1000
ml of distilled water.
When we search the literature, the material,
K2HCO3, was not found in the formation of artificial
saliva. Also, the pharmacists was not able to prepare
artificial saliva for our study according to the formula
that was given by Lucchetti et al.1 We believe there is
a typographical error in the article that needs to be
corrected to prevent encountering the same problem in
the future studies.
Faruk Emir, PhD
Prosthodontist
Dental Health Sciences Center
Department of Prosthodontics
Gülhane Military Medical Academy
Ankara, Turkey
Simel Ayyildiz, DDS, PhD
Associate Professor
Dental Health Sciences Center
Department of Prosthodontics
Gülhane Military Medical Academy
Ankara, Turkey
REFERENCES
1. Lucchetti MC, Fratto G, Valeriani F, De Vittori E, Giampaoli S, Papetti P,
Spica VR, Manzon L. Cobalt-chromium alloys in dentistry: An evaluation of
metal ion release. J Prosthet Dent 2015;114:602-8.
2. Matos IC, Bastos IN, Diniz MG,Mirana MS. Corrosion in artificial saliva of
Ni-Cr-based dental alloy joined by TIG welding and conventional brazing.
J Prosthet Dent 2015;114:278-85.
3. Ionta FQ, Mendonça FL, de Oliveira GC, de Alencar CRB, Honório HM,
Magalhães AC, Rios D. In vitro assessment of artificial saliva formulations
on initial enamel erosion remineralization. J Dent 2014;42:
175-9.
4. Almqvist H, Lagerlöf F. Effect of intermittent delivery of fluoride to solution
on root hard-tissue de- and remineralization by I125 adsorptiometry. J Dent
Res 1993;72:1593-8.
5. Mutlu-Sagesen L, Ergun G, Karabulut E. Ion release from metal-ceramic
alloys in three different media. Dent Mater J 2011;30:598-610.
6. International Standards Organization. ISO 10271. Dentistry-corrosion test
methods for metallic materials Geneva: ISO. Available at: http://www.iso.org/
iso/store.htm. Accessed July 3, 2014.
Authors’ Response
Dear Editor:
We are glad our paper was of interest and very sorry if a
clerical error occurred in reporting the formula in the
manuscript.1,2 Indeed, that formula cannot chemically
exist, not only because some components are missing,
but because K2HCO3 geometry is clearly impossible for
the valence bonds. We thank colleagues and referees for
their observations and apologize to readers for any difficulty
they may have encountered in trying to prepare
this solution for artificial saliva.
The correct composition is: 4.4 10-2 M K2HPO4,
1.8 10-2 M KH2PO4, 9.1 10-2 M NaCl, and 1.25 10-1 M
KCl.
In using the solution we did not encounter any problems
and it was very stable for 4 weeks at 4C.
Special care was not needed to solve the components
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