High-power excilamps with short-pulse duration

Peri-implantitis (PI) is an inflammatory disease of peri-implant tissues, it represents the most frequent complication of dental implants. Evidence revealed that microorganisms play the chief role in causing PI. The purpose of our study is to evaluate the cleaning of contaminated dental implant surfaces by means of the Q-switch Nd:YAG (Neodymium-doped Yttrium Aluminum Garnet) laser and an increase in temperature at lased implant surfaces during the cleaning process. Seventy-eight implants (titanium grade 4) were used (Euroteknika, Sallanches, France). Thirty-six sterile implants and forty-two contaminated implants were collected from failed clinical implants for different reasons, independent from the study. Thirty-six contaminated implants were partially irradiated by Q-switch Nd:YAG laser (1064 nm). Six other contaminated implants were used for temperature rise evaluation. All laser irradiations were calibrated by means of a powermetter in order to evaluate the effective delivered energy. The irradiation conditions delivered per pulse on the target were effectively: energy density per pulse of 0.597 J/cm2, pick powers density of 56 mW/cm2, 270 mW per pulse with a spot diameter of 2.4 mm, and with repetition rate of 10 Hz for pulse duration of 6 ns. Irradiation was performed during a total time of 2 s in a non-contact mode at a distance of 0.5 mm from implant surfaces. The parameters were chosen according to the results of a theoretical modeling calculation of the Nd:YAG laser fluency on implant surface. Evaluation of contaminants removal showed that the cleaning of the irradiated implant surfaces was statistically similar to those of sterile implants (p-value ≤ 0.05). SEM analysis confirmed that our parameters did not alter the lased surfaces. The increase in temperature generated at lased implant surfaces during cleaning was below 1 °C. According to our findings, Q-switch Nd:YAG laser with short pulse duration in nanoseconds is able to significantly clean contaminated implant surfaces. Irradiation parameters used in our study can be considered safe for periodontal tissue.

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Point source of UV-radiation with a frequency of 1 khz and short pulse duration

Russian Physics Journal ◽

10.1007/s11182-012-9742-4 ◽

2012 ◽

Vol 54 (11) ◽

pp. 1276-1279 ◽

Cited By ~ 1

Author(s):

E. Kh. Baksht ◽

V. F. Tarasenko ◽

Yu. V. Shut’ko ◽

M. V. Erofeev

Keyword(s):

Point Source ◽

Pulse Duration ◽

Uv Radiation ◽

Short Pulse ◽

Short Pulse Duration

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Forming Fine V-Grooves on a Tungsten Carbide Workpiece with a PCD Electrode by EDM

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.329.631 ◽

2007 ◽

Vol 329 ◽

pp. 631-636 ◽

Cited By ~ 2

Author(s):

Sadao Sano ◽

Kiyoshi Suzuki ◽

Wei Li Pan ◽

Manabu Iwai ◽

Yoshihiko Murakami ◽

...

Keyword(s):

Tungsten Carbide ◽

Pulse Duration ◽

Flat Surface ◽

Short Pulse ◽

Chemical Vapor ◽

Polycrystalline Diamond ◽

Chemical Vapor Deposition Diamond ◽

Electrically Conductive ◽

Short Pulse Duration ◽

Low Wear

Polycrystalline diamond (PCD) exhibits a thermal conductivity similar to that of the electrically conductive chemical vapor deposition diamond (EC-CVD diamond) found to function as zero-wear electrodes at short pulse duration. In this study, PCD was used as electrodes applied to EDM on tungsten carbide. Two kinds of PCD (CTB-010 and CTH-025) with a flat surface were used. The wear of the PCD electrodes was about 1.5% for very short pulse duration such as te=1μs, but it was zero wear at te=30μs, though the wear of a Cu-W electrode was 10% even on the machine recommended conditions for the low wear. EDM experiment using a V-shaped PCD electrode with an included angle of 45° was also carried out and the performance was compared with the case using a V-shaped Cu-W electrode. Under the conditions of a no load voltage of 60V, a set peak current of 2A, and a medium pulse duration of te=15μs, there was no wear on PCD electrodes when observed under the SEM, whereas a 50μm-deep wear on the Cu-W electrodes even under the machine recommended condition for the low wear was observed.

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