Paper
28 May 2004 Evaluation of some properties of dental ceramic as affected by different types of lasers and gamma radiations
Yehia Badr, M. A. El'Khoudary, Iman Annan
Author Affiliations +
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.
© (2004) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Yehia Badr, M. A. El'Khoudary, and Iman Annan "Evaluation of some properties of dental ceramic as affected by different types of lasers and gamma radiations", Proc. SPIE 5313, Lasers in Dentistry X, (28 May 2004); https://doi.org/10.1117/12.524219
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KEYWORDS
Excimer lasers

Gamma radiation

Ceramics

Crystals

Femtosecond phenomena

Nd:YAG lasers

X-ray diffraction

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