Evaluation of irradiation effects of near-infrared free-electron-laser of silver alloy for dental application

Kuwada-Kusunose, Takao; Kusunose, Alisa; Wakami, Masanobu; Takebayashi, Chikako; Goto, Haruhiko; Aida, Masahiro; Sakai, Takeshi; Nakao, Keisuke; Nogami, Keiji; Inagaki, Manabu; Hayakawa, Katsumi; Suzuki, Kunihiro; Tanaka, Sakae

doi:10.1007/s10103-017-2251-5

Cited by 4 publications

(3 citation statements)

References 24 publications

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“…As described above, the laser used in the present study has a pulse width of several hundred femtoseconds, and the ablation efficiency for the same average power is expected to be much lower than that for microsecond or nanosecond laser pulses (23) . As a result, for the same average power, it is necessary to increase the number of pulse irradiations in order to achieve sufficient processing.…”

Section: Discussionmentioning

confidence: 99%

Dependence of Pit Formation in Hard Tissue of Human Teeth on Free Electron Laser Pulse Structures

2023

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The purpose of this study was to compare and clarify the differences in pit formation between two modes of freeelectron laser (FEL) irradiation with different beam currents and pulse structures and how the effects of these modes vary with the tissue structure of human teeth.FEL irradiation using the fullbunch mode (Fm) and burst mode (Bm) . The beam current was carried out at 200 mA for Fm and 2 A for Bm. The micropulse interval within the macropulse structure was 350 ps for Fm and 22.4 ns for Bm. The wavelength of the FEL was adjusted to 2.94 µm, and macropulse energy was adjusted to 6.0 mJ/ macropulse by polarizing plate. The macropulse irradiation was set to 1 or 5 times for both modes.As the number of macropulse irradiations increased, the pits became deeper in Fm than in Bm, regardless of the site on the tooth. On the other hand, the bulge height was lower for Bm than for Fm, regardless of the site on the tooth or the number of macropulse irradiations. No scorch marks were observed in the pits for either mode.It was concluded that the differences in the pit including bulge formation were the macropulse structure between Fm and Bm. The intensity of the FEL irradiation caused plasma evaporation in the tooth hard tissue, and the tooth substance was ablated before thermal conduction occurred. The relation with the thermal relaxation time also confirmed that pits were formed without visible scorch marks.

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Section: Discussionmentioning

confidence: 99%

Dependence of Pit Formation in Hard Tissue of Human Teeth on Free Electron Laser Pulse Structures

2023

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“…An IR-FEL system at Kyoto University named KU-FEL was used for mid-infrared radiation [28], and the laser system at LEBRA of Nihon University was used for nearinfrared radiation [29,30]. An electron beam is provided by an electron-linear accelerator, and the IR-FEL can be produced by the interaction between the synchrotron radiation stored in an optical resonator and the electron beam in the undulator.…”

Section: Infrared Free Electron Laser Irradiationmentioning

confidence: 99%

Degradation of Lignin by Infrared Free Electron Laser

et al. 2022

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Lignin monomers have attracted attention as functional materials for various industrial uses. However, it is challenging to obtain these monomers by degrading polymerized lignin due to the rigid ether linkage between the aromatic rings. Here, we propose a novel approach based on molecular vibrational excitation using infrared free electron laser (IR-FEL) for the degradation of lignin. The IR-FEL is an accelerator-based pico-second pulse laser, and commercially available powdered lignin was irradiated by the IR-FEL under atmospheric conditions. Synchrotron-radiation infrared microspectroscopy analysis showed that the absorption intensities at 1050 cm−1, 1140 cm−1, and 3400 cm−1 were largely decreased alongside decolorization. Electrospray ionization mass chromatography analysis showed that coumaryl alcohol was more abundant and a mass peak corresponding to hydrated coniferyl alcohol was detected after irradiation at 2.9 μm (νO-H) compared to the original lignin. Interestingly, a mass peak corresponding to vanillic acid appeared after irradiation at 7.1 μm (νC=C and νC-C), which was supported by our two-dimensional nuclear magnetic resonance spectroscopy analysis. Therefore, it seems that partial depolymerization of lignin can be induced by IR-FEL irradiation in a wavelength-dependent manner.

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“…In the current study, we propose a novel green process for degradation of cellulose to obtain low-molecular-weight sugars by using an infrared free electron laser (IR-FEL). The IR-FEL is generated by strong interaction of synchrotron radiation (SR) with the accelerated electron beam in the periodic magnetic field (refs − ; the outline of the laser system is shown in section 1.2 and Figure S1 in the Supporting Information). In principle, the oscillation wavelengths range widely from near- to far-infrared rays (3–100 μm) and with various wavelengths that can resonate with many functional groups, and the collective vibrational modes are contained in those infrared regions.…”

Section: Introductionmentioning

confidence: 99%

Cellulose Degradation by Infrared Free Electron Laser

et al. 2020

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We introduce a green approach to obtain glucose and low-molecular-weight saccharides directly from the cellulose aggregate by using near-and mid-infrared free electron lasers (IR-FELs). The IR-FEL is a synchrotron radiation based picosecond pulse laser where the oscillation wavelengths are tunable from 3 to 10 μm. Electrospray ionization mass spectroscopy analysis showed that mass peaks of glucose (203 Da), cellobiose (365 Da), trisaccharide (527 Da), and tetrasaccharide (689 Da) were clearly detected as each sodium ion adduct in the soluble fraction after the powdered cellulose was serially irradiated by the IR-FEL tuned to 9.1 μm (νC−O) following 7.2 μm (δH−C−O) or 3.5 μm (νC−H). The production yields of these saccharides were higher than those obtained by the single irradiation at 9.1 μm, as shown by the mass chromatogram analysis. The cleavage of the glucoside bonds was revealed by synchrotron radiation infrared microscopy analysis: the infrared absorption peak of the C−O bonds at 1100 cm −1 was obviously reduced, and the bandwidth of the broad peak of O−H bonds at 3400 cm −1 was shortened after those irradiations. The laser irradiation system suggested herein is based on the vibration mode selective multiphoton absorption reaction and requires no cosolvents and no high temperatures and pressures to exert the irradiation effect. One day of operation can process several hundred milligrams of the solid cellulose sample at the current laboratory scale.

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Evaluation of irradiation effects of near-infrared free-electron-laser of silver alloy for dental application

Cited by 4 publications

References 24 publications

Dependence of Pit Formation in Hard Tissue of Human Teeth on Free Electron Laser Pulse Structures

Dependence of Pit Formation in Hard Tissue of Human Teeth on Free Electron Laser Pulse Structures

Degradation of Lignin by Infrared Free Electron Laser

Cellulose Degradation by Infrared Free Electron Laser

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