- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
A simple extended-cavity diode laser using a precision mirror mount
摘要： We have developed an extended-cavity diode laser (ECDL) with a simple design by using a commercial precision mirror mount with minor modifications. Our design allows tuning of the external cavity configuration by tweaking the volume holographic grating without troublesome changes in the beam path of the laser output. The mode-hop-free tuning range of the presented ECDL is about 8 GHz with a linewidth of 475 kHz.
关键词： volume holographic grating,mode-hop-free tuning range,linewidth,extended-cavity diode laser,precision mirror mount
更新于2025-09-23 15:21:01
-
Effects of 445-nm Diode Laser-Assisted Debonding of Metallic Brackets on Shear Bond Strength and Enamel Surface Morphology
摘要： Objective: To evaluate the effect of a 445-nm diode laser on the shear bond strength (SBS) of metallic brackets before debonding. Background: Due to the new blue laser technology, very few studies are available in this context. Methods: Seventy metallic brackets (Discovery; Dentaurum, Ispringen, Germany) were bonded to the frontal enamel surfaces of 70 caries-free bovine incisors in a standardized way. Each sample was randomly assigned to the control or laser group, with 35 samples per group. The brackets in the laser group were irradiated with the diode laser (SIROLaser Blue(cid:2); Sirona, Bensheim, Germany) on three sides of the bracket bases for 5 s each (lateral–coronal–lateral, a total of 15 s) immediately before debonding. SBS values were evaluated for the control group and laser group. Micrographs of the enamel surface were taken with 10 · magni?cation to assess the adhesive remnant index (ARI) and the degree of enamel fractures after debonding. Results: There were no statistically signi?cant differences in SBS in the laser group in comparison with the control group ( p > 0.05). The distribution of ARI scores was also not statistically signi?cantly different in the laser group in comparison with the control group ( p > 0.05). Three enamel fractures occurred in the control group and one in the laser group after debonding. Conclusions: Irradiation of metallic brackets with the 445-nm diode laser before debonding does not signi?cantly reduce the SBS values and does not in?uence the remaining amount of adhesive on the enamel surface. The risk of enamel fractures during debonding is therefore not clinically affected.
关键词： adhesive remnant index,orthodontics,metallic bracket debonding,445-nm diode laser
更新于2025-09-23 15:21:01
-
EXPRESS: Influence of Line Pair Selection on Flame Tomography Using Infrared Absorption Spectroscopy
摘要： We report the influence of absorption line selection on the tomographic results for high-temperature flames by numerical and experimental methods. Different combinations of infrared H2O absorption transitions are utilized with the Tikhonov-regularized Abel inversion to reconstruct the radial distribution of temperature and H2O concentration in a flat flame. It is shown that besides using the mathematical algorithm such as regularization, selecting a line pair with a large ΔE″ (> 1390 cm–1) also reduces the reconstruction uncertainty at 300–2000 K. In this study, a proper selection of absorption line pairs reduces the reconstruction uncertainty by 25% at the same level of noise. The line pair of H2O transitions at 4029.524 cm–1 and 4030.729 cm–1 is recommended for the tomography of high-temperature flames at 1000–3000 K, whereas the line pair of 7185.597 cm–1 and 7444.352 cm–1 can be used at 300–1000 K.
关键词： tunable diode laser absorption spectroscopy,TDLAS,Tomography,high-temperature flame,line selection
更新于2025-09-23 15:21:01
-
Antibacterial efficacy of 810-nm diode laser on the biofilm formation by Enterococcus faecalis in root canals: an in vitro study
摘要： Aim This study aimed to evaluate the antibacterial efficacy of 810-nm diode laser on the root canals infected with Enterococcus faecalis biofilm-like structure by using comparable and safe parameters. Methodology The root canals of 52 extracted human single-rooted teeth were prepared, 4 teeth allocated as negative control and 48 teeth inoculated with E. faecalis for 3 weeks. The teeth were then randomly divided into the following 4 experimental groups: Group NaOCl (n = 12), 17% EDTA + 5.25% NaOCl + saline; Group DL1 (n = 12), 17% EDTA + 1 W diode laser + saline; Group DL2 (n = 12), 17% EDTA + 1.5 W diode laser + saline; Group S (n = 12), Saline. Samples were obtained from dentin chips before and after the interventions. A reduction in colony count was assessed by counting the colony-forming units. Results Compared to the control group, significant reductions were noted in E. faecalis colony counts in all groups (p < .05) except Group S (p > .05). The greatest reduction in colony count (98.9%) was noted in the Group NaOCl. The difference in this respect between the Group DL2 and Group S (p < .05) was significant; however, no significant difference was noted between Group DL1 and Group S (p > .05). Conclusion Our results demonstrated two different parameters of 810-nm diode laser showing the significant antibacterial effect on E. faecalis biofilm but it was not as effective as NaOCl irrigation.
关键词： Root canal,Enterococcus faecalis,Diode laser
更新于2025-09-23 15:21:01
-
Diode Laser Spectroscopy for Creating Effective Measuring Systems and Their Use in Biological and Medical Research
摘要： In this paper, we present the most important principles of diode laser spectroscopy, which allow one to create fundamentally new measuring systems for diverse applications in biology and medicine. Using the diode laser spectroscopy method and its primary hardware implementation the emission of gas molecules from skin of the hand was registered and ammonia skin emission was found to be dominant. The properties of exhaled air from patients in different states were determined with another special measuring complex of diode laser spectroscopy. It was shown that when the functional state of the body changes, the gas composition of molecular substances that are present in the exhaled air is altered indirectly and their levels vary significantly depending on the health of the individual. Our findings suggest that it is possible to study the specific functional properties of the human body to facilitate assessment of the health of an individual to determine whether pathological processes occur in the body at various stages of their severity using diode laser spectroscopy. This paper presents clinical and experimental data on this issue.
关键词： non-invasive diagnostics,diode lasers,gas biomarkers,diode laser spectroscopy
更新于2025-09-23 15:19:57
-
Effectiveness of Different Laser-Assisted In-Office Bleaching Techniques: 1-Year Follow-Up
摘要： Objective: The aim of this study was to evaluate color longevity after different bleaching techniques. Background: Laser-activated bleaching methods are gaining popularity due to decreased chair time and increased patient compliance. However, the longevity of such methods has not been stated clearly. Methods: Sixty patients were divided into the following three groups (n = 20); group 1: chemical bleaching with 35% hydrogen peroxide (HP) gel, group 2: bleaching with 35% HP gel with diode laser activation, and group 3: bleaching with 35% HP gel with Er,Cr:YSGG laser activation. Color changes (DE*) were calculated by using two different formulas: (i) CIELAB (DEab) and (ii) CIEDE2000 (DE00) with a spectrophotometer before treatment, 24 h after treatment 3, 6, and 12 months after treatment. Evaluation of postoperative sensitivity was performed before and immediately after treatment, followed by re-evaluation 24 h and 1 week after treatment. Results: For DEab calculation, no significant difference was observed during both intra- and inter-group evaluations ( p > 0.05). For DE00 calculation, no significant intergroup difference was observed ( p > 0.05), whereas significant intragroup differences between the values of after treatment, 6–12 months. In the chemical bleaching group, increased postoperative sensitivity was observed after 24 h ( p < 0.001). In the diode-laser-activated group, postoperative hypersensitivity was detected at 24 h and 1 week. No significant hypersensitivity was observed in the Er,Cr:YSGG-laser-activated group ( p > 0.05). Conclusions: All three techniques provided efficient bleaching. Chemical and diode-activated bleaching methods resulted in slight sensitivity after application, whereas Er,Cr:YSGG-laser-activated bleaching did not cause sensitivity.
关键词： diode laser,laser-assisted bleaching,Er,Cr:YSGG laser,hydrogen peroxide
更新于2025-09-23 15:19:57
-
Outcomes of Two Treatments for Uncomplicated Pilonidal Sinus Disease: Karydakis Flap Procedure and Sinus Tract Ablation Procedure Using a 1,470a??nm Diode Laser Combined With Pit Excision
摘要： Background and Objectives: An ideal treatment for pilonidal disease should feature a low recurrence rate, minimal incision, and rapid return to daily activities. We compared the outcomes of the well‐defined Karydakis technique (KT) and a combination of pit excision (PE) and sinus tract ablation using 1,470‐nm diode laser. Study Design/Materials and Methods: In this study, from January 2016 to January 2018, patients diagnosed with uncomplicated early‐stage pilonidal sinus disease were enrolled and were treated randomly, using KT (n = 28) or a PE/laser ablation technique (PE + LAT; n = 30). Results: The mean operative times were 36.4 (25–45) minutes in the KT group and 15.1 (12–20) minutes in the PE + LAT group. Postoperative Visual Analog Scale pain scores were 4.4 in the KT group and 2.1 in the PE + LAT group. The time periods to return to normal daily activities were 2.6 (1–5) days in the PE + LAT group and 12.8 (10–20) days in the KT group. The mean Likert satisfaction scores were 3.8 in the KT group and 4.8 in the PE + LAT group. The groups did not differ in terms of recurrence. Conclusions: Compared with the KT, the PE + LAT was associated with a shorter operative time, a more rapid return to normal activities, less pain, and a higher level of subjective satisfaction. We found that the PE + LAT was better than the KT for patients with early‐stage disease.
关键词： pilonidal sinus,karydakis,minimally invasive surgery,1,470‐nm diode laser,laser ablation,pit picking
更新于2025-09-23 15:19:57
-
Time-dependent 3D modeling of the thermal analysis of the high-power diode laser hardening process
摘要： In this paper, the thermal analysis of the high-power diode laser hardening process was modeled on AISI 4130 steel. Afterward, the depth and width of hardness were predicted based on the complete austenite temperature (AC3). Due to the dimensions and output beam power of the diode laser stack (DLS), it is impossible to achieve the suitable power density (103-105 W/cm2). Furthermore, the output intensity profile of the DLS is not homogeneous because of the pitch between the emitters. Thus, to achieve a suitable power density and a uniform beam profile, an optical layout was designed. The beam profile was experimentally obtained by a beam profiler at different distances from the focal plane and was compared with the modeling results. Due to the agreement between the modeling and experimental results, the intensity value of each mesh of the laser profile was extracted from the ZEMAX software. Then, for the thermal analysis of the laser hardening process (LHP), it was entered as a heat flux input into the COMSOL Multiphysics software.
关键词： Thermal analysis,Intensity profile,High power diode laser,Laser hardening,Complete austenite temperature
更新于2025-09-23 15:19:57
-
Long-term effect of low-level diode laser irradiation on proliferation of stem cells from human exfoliated deciduous teeth after cryopreservation protocol
摘要： Low-level laser irradiation (LLLI) could be useful for the stimulation of stem-cell proliferation. LLLI has important physiological properties which increase the mitochondrial activity of cells. This study aimed to evaluate the biological effect of LLLI on cryopreserved stem cell from human exfoliated deciduous teeth (SHEDs). Cryopreserved and characterised SHEDs from a previous study were used for this study. The SHEDs were exposed to GaAlAs diode laser with energy densities of 1.2 (Group 2) and 2 J cm?2 (Group 3). For the control group (Group 1), SHEDs were cultured in culture medium including Dulbecco’s modified Eagle’s Medium supplemented with 15% foetal bovine serum, 1% L-glutamine, 1% penicillin-streptomycin, 1% gentamycin, and amphotericin-B. The cells in the experimental groups were irradiated as previously indicated, and after the irradiation were incubated for 0, 24, 48, and 72 h at 37 °C in 5% CO2. Proliferation of SHEDs was analysed by 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide assay at incubation periods of 0, 24, 48, and 72 h after the single-laser irradiation. The effects of laser irradiation on apoptosis of SHEDs at the last incubation period (72 h) were detected with the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labelling (TUNEL) method. Group 2 showed increased TUNEL-positive cells compared to Groups 1 and 3, but no significant differences between the three groups were observed (p > 0.05). Comparing Groups 2 and 3 to Group 1, the proliferation of SHEDs significantly increased after 24, 48, and 72 h (p < 0.05), but no significant differences were observed between the groups at 0 h (p > 0.05). In addition to this, at 72 h, Group 3 showed significantly higher proliferative effect on SHEDs compared to Group 2 (p > 0.05). In terms of clinical usage of long-term cryopreserved SHEDs, we can recommend to clinicians and researchers that prior to their use, LLLI may be used to increase the proliferation rate.
关键词： cryopreserved stem cells,low-level diode laser irradiation (LLLI),apoptosis,proliferation
更新于2025-09-23 15:19:57
-
Experimental observation of the vibration-rotation radiation curves of <sup>12</sup> C <sup>16</sup> O <sub/>2</sub> and <sup>13</sup> C <sup>16</sup> O <sub/>2</sub> absorption constants ranging from 4860 to 4880 sm <sup>a??1</sup> by the tunable diode laser absorption spectroscopy method
摘要： We report the experimental observation of the absorption constant values of 12C16O2 and 13C16O2 using the tunable diode laser absorption spectroscopy method ranging from 4860 to 4880 sm?1 within the pressure limits of 8–240 mbar for the absorption curves (lines) R(18), R(20), R(22), R(24), R(26), R(28), R(30), R(32), R(34) and R(36) of the 20013–00001 molecule 12C16O2 vibration band, and within the pressure limits of 0.06–1.7 mbar for the absorption curves P(10), P(12), P(14), P(16), P(18), P(20) and P(22) of the 20012–00001 molecule 13C16O2 vibration band. In the work, as a mixture under analysis, a mixture of the isotopes 13C16O2 and 12C16O2 at the ratio of 1:140 was used. The results have been compared with the data of the HITRAN spectroscopic database.
关键词： tunable diode laser absorption spectroscopy,carbon dioxide,absorption coefficients
更新于2025-09-23 15:19:57