Laser Welded Ni-Cr Dental Alloys Inspection

Minor problems arising from optimizations by welding of fixed prostheses frameworks can be identified by macroscopic and microscopic visual inspection. The purpose of this study was to highlight the visible discontinuities present in the laser welds of dental Ni-Cr alloys. Ni-Cr base metal alloys designated for fixed prostheses manufacture were selected for the experiments. Using cast plates, preliminary tests were conducted by laser welding. Macroscopic visual inspection was done carefully to assess the defects of the welding rib. Electron microscopy images allowed visualization of small discontinuities, which escapes visual inspection. Making comparison to Ni-Cr alloys taken in the experiment and laser welded, after visual analysis, the best welds appear for Heraenium NA alloy.

Authors:

• Porojan S.
• Sandu L.
• Topală F.

Keywords:

• macroscopic visual inspection
• electron microscopyimages
• Ni-Cr dental alloys
• laser welding.

References:

[1] Jeffus, L. (2008). Welding: Principles and applications, 6th edition.
Thomson Delmar Learning, ISBN 978-1-4180-5275-1, New York.
[2] Baba, N, & Watanabe, I. (2005). Penetration depth into dental casting
alloys by Nd:YAG laser, J Biomed Mater Res B Appl Biomater,
72(1):64-8, ISSN 1552-4973.
[3] Bertrand, C. &, Poulon-Quintin A. (2010). Proposals for Optimization of
Laser Welding in Prosthetic Dentistry. J Prosthodont, 19(1):69-76, ISSN
0893-2174.
[4] Watanabe, I.; Baba, N.; Chang, J. & Chiu, Y. (2006). Nd:YAG laser
penetration into cast titanium and gold alloy with different surface
preparations. J Oral Rehabil, 33:443-6, ISSN 0305-182X.
[5] Sandu, L.; Porojan, S.; Topalâ, F.; Ciuluvicâ, R.; Stana, D. &
Alexandrescu C. (2010). Digital evaluation of discontinuities on dental
alloys microplasma welds. Metalurgia International vol . XV, Sp iss no.
9: 24-7, ISSN 1582-2214.
[6] Baba, N.;, Watanabe, I.; Liu, J.& Atsuta, M. (2004). Mechanical strength
of laser-welded cobalt-chromium alloy. J Biomed Mater Res B Appl
Biomater. May 15;69(2):121-4, ISSN 1552-4973.
[7] Bertrand, C.; Le Petitcorps, Y.; Albingre, L. & Dupuis V. (2004).
Optimization of operator and phisical parameters for laser welding of
dental materials, Br Dent J, 196(7):413-8, ISSN 0007-0610.
[8] Neumann, M.O. & Lindigkeit J. (2005). Mechanische Festigkeit von
geschweißten EMF-Legierungen, Quintessenz Zahntech, 31(9):966-73,
ISSN 0340-4641.
[9] Perret, O.; Bizonard, M.; Naudy, Ph.; Pascal, G.; Nore, D. &Horde,
Y.(2001). Characterization of keyhole formed during pulsed Nd:YAG
laser interaction with a Ti-6Al-4V metallic target, J Appl Phys, 90:27-30,
ISBN 0021-8979.