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Proceedings Paper

Evaluation of some properties of dental ceramic as affected by different types of lasers and gamma radiations
Author(s): Yehia Badr; M. A. El'Khoudary; Iman Annan
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Paper Abstract

Dental ceramic:Duceram porcelain(Ducera,Dental-Gesellschaft mbH, FrankFurt, Germany) low fusing dental porcelain was subjected in this investigation to different types of laser radiations: a) Nd:YAG laser pulses o 8 ns, 200mJ/pulse for 5&10 minutes b) Tsonamy 70 fs laser pulses for 1 & 5 minutes c)193 nm Excimer laser pulses 6 &13 mJ/pulse for 5 & 10 minutes and finally d) 0.1, 0.3, 0.5 and 1 MRad of Gamma radiations using 10 samples for each type of radiation. Knoop hardness values of test samples were measured using a knoop hardness tester(KHN-Ernst Leitz Wetzlar Germany)showing increased hardness values for all test irradiated samples as compared with the control. Highest hardness value were recorded for Excimer laser 13 mJ/pulse-10 minutes(670kg/mm2 as compared with 410kg/mm2 for the control. On the other hand, the highest value for the transverse strength was obtained for Excimer laser 3.8mJ/pulse-10 minutes). To account for the structural changes occurring due to laser irradiations and leading to the detected here improvement in the mechanical properties we used several techniques which are known to be sensitive to any structural changes such as: x-ray diffraction, SE-Microscopy, FTIR & Raman spectroscopy. Our observations showed series of variations indicating good accordance in the introduced here results. A reasonable interpretation is given here for the effects and variations observed in our measurements and spectra as a result of both Gamma and Laser irradiation. Finally, the given here results indicated that Laser irradiation can be used as a powerful tool for improving the hardness and transverse strength of dental ceramic.

Paper Details

Date Published: 28 May 2004
PDF: 19 pages
Proc. SPIE 5313, Lasers in Dentistry X, (28 May 2004); doi: 10.1117/12.524219
Show Author Affiliations
Yehia Badr, Cairo Univ. (Egypt)
M. A. El'Khoudary, Cairo Univ. (Egypt)
Iman Annan, Cairo Univ. (Egypt)


Published in SPIE Proceedings Vol. 5313:
Lasers in Dentistry X
Peter Rechmann; Daniel Fried; Thomas Hennig, Editor(s)

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