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A Novel Combined Light-Based Treatment of Acne Vulgaris With 1,450-nm Diode Laser and 450-nm Blue Light
摘要： BACKGROUND Nonablative 1,450-nm diode laser (DL) and visible blue light (BL) have been effectively used for acne with superior safety pro?les. OBJECTIVE To evaluate synergistic effects of sequential DL and BL application for acne. METHODS A 20-week, randomized split-face study was conducted to compare clinical courses between 2 facial sides either receiving sequential application of DL and BL or BL alone in 24 patients with mild to moderate facial acne vulgaris. Patients were scheduled to receive 3 consecutive sessions at 4-week intervals. Objective assessments, including revised Leeds grades, lesion counts, and sebum output measurements, and patients’ subjective satisfaction were investigated. RESULTS Both combination and BL sides demonstrated steady improvement of in?ammatory acne lesions with 62.3% and 35.2% decreases at the 12-week follow-up visit compared with baseline respectively. For nonin?ammatory lesions and seborrhea, only combination regimen demonstrated improvement. Patients’ subjective assessments paralleled objective ?ndings. For safety pro?les, no severe adverse effect was observed on both sides, and mild symptoms resolved spontaneously within a day. CONCLUSION The combination regimen demonstrated synergistic ef?cacies for acne and seborrhea, with satisfactory safety pro?les. Therefore, a few sessions of these light-based applications would be a viable option for acne treatments.
关键词： combination treatment,acne vulgaris,diode laser,blue light,seborrhea
更新于2025-09-12 10:27:22
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MANAGEMENT OF GIANT RETINAL TEARS USING TRANSSCLERAL DIODE LASER RETINOPEXY AND SHORT-TERM POSTOPERATIVE TAMPONADE WITH PERFLUORO-N-OCTANE
摘要： To determine the results of pars plana vitrectomy for giant retinal tear detachments using transscleral diode laser retinopexy and short-term postoperative tamponade with perfluoro-n-octane (PFnO). Twenty consecutive patients with fresh giant retinal tears were enrolled in a single-arm prospective study. One case was withdrawn for technical reasons. The remainder all underwent pars plana vitrectomy, PFnO injection, transscleral diode laser retinopexy to the edge of the giant retinal tear, and short-term postoperative heavy liquid tamponade. None of the cases had scleral buckling or lensectomy. Nineteen cases (18 male and 1 female) with a mean age of 41 years (range 10–69 years) were followed up for a period of 6 months. Postoperative tamponade with PFnO was maintained for a mean of 7.6 days (range 4–21 days), after which it was exchanged for sulfur hexafluoride (SF6), perfluoropropane (C3F8) gas, or balanced salt solution. Final reattachment rate was 100%, with 3 (15.7%) patients requiring additional surgery. Best-corrected visual acuity at final follow-up was 20/40 or better in 11 eyes (58%), between 20/60 and 20/200 in 7 (37%), and 20/400 in 1 (5%). In this series of acute giant retinal tears, transscleral diode laser retinopexy together with the use of PFnO for short-term postoperative tamponade achieved excellent anatomical and visual results.
关键词： vitrectomy,giant retinal tear,perfluoro-n-octane,retinal detachment,perfluorocarbon liquid,transscleral diode laser retinopexy
更新于2025-09-12 10:27:22
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The Comparison of Thermal Effects of a 1940‐nm Tm:fiber Laser and 980‐nm Diode Laser on Cortical Tissue: Stereotaxic Laser Brain Surgery
摘要： Background and Objectives: The thermal damage on adjacent healthy structures is always an unwanted consequence of continuous‐wave laser irradiation of soft tissues. To propose a laser as an effective alternative to traditional surgical tools, this photothermal damage due to heat conduction must be taken into account with a detailed laser dosimetry study. Two candidate lasers; a 980‐nm diode and 1940‐nm Tm:fiber were selected for this study. Despite the poor absorption by water, the 980‐nm diode laser has been one of the most widely used lasers in soft tissue surgeries due its good absorption by hemoglobin, which provides good homeostasis. The second laser; the Tm:fiber laser was selected due to its wavelength operating at an absorption peak of water (1,940 nm), which makes it a good candidate for ablation of biological tissues, and it is readily capable of being transmitted through flexible fiber optics to deliver energy to hard‐to‐reach regions. The underlying motivation for the research described in this paper is that with a comprehensive comparison of ablation capabilities and a detailed dose study of infrared lasers operating at different wavelengths and temperature monitoring of the tissue during laser surgery, it may be possible to specify the optimal laser parameters for laser surgery, and propose a treatment alternative to conventional surgical techniques in clinical use. The objectives of this study were to investigate and to compare the thermal effects of 980‐nm and 1940‐nm lasers on cortical tissue in vivo, to find the optimum parameters for laser‐brain‐ablation with minimum thermal damage to the surrounding healthy tissue, and finally, to analyze laser irradiated tissue thermographically and histologically to correlate thermal events and tissue damage with laser irradiation parameters. Study Design/Materials and Methods: Stereotaxic laser brain surgeries were performed on 32 male Wistar rats. A t‐type thermocouple was used to measure the temperature of the nearby tissue at a distance of 1 mm above and 1 mm away from the fiber tip during laser surgery. Cresyl fast violet (CFV) staining was used to expose the thermal extent of laser surgery on cortical tissue. Eight tissue samples from each laser study group were processed for histological analysis and the mean ± standard deviation for thermal damage was reported. Thermal damage was quantified as ablation (thermally removed tissue), severe and mild coagulation (irreversible thermal damage) and edematous (reversible thermal damage) areas with regard to CFV stained slices. The Pearson correlation coefficient was calculated to test if the ablation efficiencies and total damage, and edematous areas were correlated to rates of temperature change. Results: No significant adverse effects were observed during surgeries. We found that both lasers investigated were successful in cortical tissue removal. Our results also revealed that irrespective of the mode of operation, laser wavelength and laser power, there is a strong correlation between the rates of temperature change and ablation efficiencies and a negative correlation between the rate of temperature change and total damage and edematous area. Conclusions: Both lasers investigated were successful in cortical tissue removal. We also reported that when the amount of energy delivered to the tissue was constant, the most important issue was to deliver this energy in a short time to achieve more efficient ablations with less edema around the lesion, regardless of mode of delivery (continuous or pulsed‐modulated mode), but further studies including the healing period after laser surgeries have to be performed to compare the thermal extent of damage comprehensively.
关键词： ablation efficiency,rate of temperature change,980‐nm diode laser,Thulium laser,ablation,real‐time temperature monitoring,Laser brain surgery,cortical tissue
更新于2025-09-11 14:15:04
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Feasibility of transgingival laser irradiation for antimicrobial photodynamic therapy
摘要： Aim: Diode lasers are commonly used for antimicrobial photodynamic therapy (aPDT). This study aimed to assess the feasibility of transgingival laser irradiation during aPDT and evaluate whether the photosensitizer can be activated. Materials and Methods: Four diode laser settings were assessed for transgingival irradiation: 120 mW, 80 mW, 60 mW, and 40 mW. Fifteen soft-tissue pieces from a pig’s lower jaw were prepared. The specimens’ thickness was measured and transgingival laser irradiation was performed. A digital power meter measured laser power on the other side of the tissue. The power outcome after staining of the nonbuccal aspect of the tissue with photosensitizer dye was assessed similarly. Results: Transgingival laser irradiation (average soft-tissue thickness: 0.84 ± 0.06 mm) resulted in di?erent power transmission depending on the power settings and photosensitizer. The lowest values were observed with the 40 mW setting and photosensitizer (median 3.3 mW, max. 5.0 mW, min. 2.3 mW, interquartile range 1.2), and the highest at 120 mW without photosensitizer (median 41.3 mW, max. 42.7 mW, min. 38.0 mW; interquartile range 1.5). Conclusions: This study indicates that transgingival irradiation may be suitable for aPDT, since power transmission through the gingival tissue was observed in all specimens. However, the decrease in laser power caused by both the soft tissue and the photosensitizer has to be taken into account.
关键词： Transgingival irradiation,Low-level laser therapy,Periodontitis,Diode laser,Antimicrobial photodynamic therapy
更新于2025-09-11 14:15:04
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The Effect of Diode and Er,Cr:YSGG Lasers on the Bond Strength of Fiber Posts
摘要： Background: Laser irradiation modi?es the topography and composition of dentin surface aiming to increase the retention of bonded posts. Objective: To assess the effect of dentin irradiation with Er,Cr:YSGG or diode lasers on the bond strength of ?ber posts using self-adhesive resin cement. Materials and methods: Sixty bovine root canals were root-canal treated, post spaces were prepared, and subsequently ?ber posts were cemented. The samples were distributed according to the surface treatment: distilled water (control), Er,Cr:YSGG (1.5 W, 20 sec), or diode (1.5 W, 20 sec) lasers. Bond strengths were assessed by pull-out (n = 10) or push-out testing (n = 10). Pearson’s correlation was calculated. Failure mode after testing and the depth of tags in the dentinal tubules were analyzed by confocal laser microscopy. Data were submitted to analysis of variance and Tukey’s test. A p < 0.05 was considered signi?cant. Results: In the push-out test, Er,Cr:YSGG laser had signi?cantly different higher values (5.43 – 0.10 MPa) compared to the control (4.79 – 0.05 MPa). Diode laser values were not signi?cantly different from the other groups (5.12 – 0.27 MPa). In the pull-out test, there were no signi?cant differences between Er,Cr:YSGG (6.86 – 2.16 MPa) and diode (8.43 – 1.77 MPa) lasers, and both had signi?cant differences compared to the control (4.18 – 1.29 MPa). No correlation was found. Adhesive failures were predominant in all groups, and no signi?cant differences in tag penetration among the groups were found. Conclusions: The Er,Cr:YSGG laser increases the bond strength of resin cement and ?ber post to dentin in both tests, compared to control group without laser treatment. Diode laser only enhanced bonding for pull-out test.
关键词： dentistry,bond strength,Er,Cr:YSGG laser,?ber post,Diode laser
更新于2025-09-11 14:15:04
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Transendoscopic correction of epiglottic entrapment with a silicone‐covered laser guide and diode laser in 29 horses
摘要： Objective: To describe the use of a silicone-covered laser guide and diode laser for surgical correction of epiglottic entrapment and report postoperative outcomes in horses with epiglottic entrapment. Study design: Retrospective case series. Animals: Thoroughbred and standardbred racehorses (n = 29) with epiglottic entrapment. Methods: A silicone-covered laser guide was placed endoscopically to direct the diode laser cutting action during transection of the entrapping subepiglottic membrane and to act as a physical barrier between the membrane and the epiglottic cartilage. Postoperative complications and trainer satisfaction were recorded via use of a follow-up questionnaire. Race records were reviewed to determine return to racing and detect differences in the number of starts, wins, or earnings before and after surgery. Results: The entrapping membrane was successfully released in all horses. Mild postoperative complications such as swelling of the surgical site (12 horses) and coughing or mild nasal discharge (5 horses) were recorded during the first few days after surgery. Ninety-six percent of trainers were satisfied with the outcome of the procedure; 93% of horses returned to racing. Conclusion: Laser guide-assisted transection of the subepiglottic membrane corrected epiglottic entrapment in standing horses. Clinical significance: Ease of surgical technique, mild postoperative complications, and a good prognosis to return to racing make this a suitable alternative to the traditional laser procedure.
关键词： diode laser,surgical correction,silicone-covered laser guide,epiglottic entrapment,horses
更新于2025-09-11 14:15:04
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Comparison of Nd:YAG laser (532 nm green) vs diode laser (810 nm) photocoagulation in the treatment of retinopathy of prematurity: an evaluation in terms of complications
摘要： Purpose To compare the anterior and posterior segment complications of diode (810 nm) laser photocoagulation (LPC) and Nd:YAG (532 nm green) LPC in the treatment of retinopathy of prematurity (ROP). Patients and methods The 84 eyes of 43 patients treated with diode LPC (group 1) and 58 eyes of 31 patients treated with Nd:YAG LPC (group 2) for ROP in our clinic were enrolled in the study. Medical records of all patients were investigated retrospectively. The patients in each group were examined in terms of birth weights, gestational weeks, stage of retinopathy, number of lasers pots, laser parameters, and anterior and posterior complications of LPC. Results The mean birth weeks of group 1 patients were postmenstrual 27.7 ± 2.5 (23–33), while the mean birth weights were 1006.0 ± 334.5 (540–1980) grams. The mean birth weeks of group 2 patients were postmenstrual 27.4 ± 2.6 (23–33), while the mean birth weights were 1073.8 ± 329.2 (480–1720) grams. The mean numbers of laser spots were 1036.0 ± 515.2 (430–2410) in group 1 per eye, while the mean numbers of laser spots were 1085.4 ± 526.0 (445–2530) in group 2 per eye (p ≥ 0.05). Additional laser application was performed in four eyes (4.8%) in group 1 and four eyes (6.9%) in group 2. Four eyes (4.8%) treated with diode LPC and one eye (1.7%) treated with Nd:YAG laser developed retinal detachment. Two eyes of a patient (3.4%) applied Nd:YAG LPC developed cataract. Conclusion Cataract may develop when Nd:YAG laser is used; however, posterior segment complications may be more likely to appear with the use of diode laser in these cases.
关键词： Nd:YAG laser photocoagulation,Cataract,Diode laser photocoagulation,Exudative retinal detachment,Retinopathy of prematurity
更新于2025-09-11 14:15:04
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Measurement of pressure shift and broadening for Ar and Kr 4s[3/2]2?→?4p[5/2]3 transition in rare gases using diode-laser spectroscopy
摘要： In this work simultaneous measurements of pressure broadening and shift coe?cients for 811.5 nm Ar and 811.3 nm Kr spectral lines of the 4s[3/2] 2 → 4p[5/2] 3 transition were performed. Assessment of gas temperature was done by determining Doppler width components of the lines’ Voigt pro?les. Pressure shift coe?cients for the mixtures Ar:Ne, Kr:Ne and Kr:Ar were determined for the ?rst time. Their values in units of 10 -10, reduced to 300 K are: β Ar:Ne = -0.51 ± 0.05, β Kr:Ne = -0.65 ± 0.01, β Kr:Ar = -2.07 ± 0.08. Additionally we demonstrated the use of easily available starters for ?uorescent lamps as sealed Ar discharge cells for reference optical frequency.
关键词： Spectral line pressure shift,Radio-frequency discharge,Metastable argon and krypton atoms,Optically pumped all-rare-gas laser,Diode-laser absorption spectroscopy
更新于2025-09-11 14:15:04
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Management of Oral Lichen Planus by 980 nm Diode Laser
摘要： Introduction: Oral lichen planus (OLP) is a mucocutaneous disease with uncertain etiology. As the etiology is unknown standard treatment modalities are not available. The traditional and common treatment relies on corticosteroids whether topical or systemic. In recent years, development of lasers made a proper path to use this instrument for treatment of the diseases which are refractory to conventional treatments. Previous studies in this field used CO2, ND:YAG, Excimer and some wavelength of diode lasers for the treatment of different types of lichen planus. Case Report: In this study, we present an OLP case which is treated using 980 nm diode laser. The result was measured by visual analogue scale (VAS) and clinical assessment; as a result, symptoms including pain and soreness started to decrease within a week, and by the end of a month completely subsided; the lesion disappeared totally as well. No recurrence was observed after a month and no side-effect was reported. Conclusion: 980 nm diode laser can be successfully used for treatment of patients with OLP.
关键词： Diode laser,Laser therapy,Traditional treatment,Oral lichen planus
更新于2025-09-11 14:15:04
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An experimental investigation of the effects of diode laser surface hardening of AISI 410 stainless steel and comparison with furnace hardening heat treatment
摘要： This study investigated the ability of the continuous wave diode laser surface hardening of AISI 410 martensitic stainless steel with a maximum power of 1600 W. Variable process parameters scanning speed (4–7 mm/s), laser power (1200–1600 W) and stand-off distance (65–75 mm) were considered in this study. Microhardness, the geometry of hardened layer (depth and width), microhardness deviation from the base metal microhardness (MHD), microstructure analysis of the laser-hardened zone through optical microscopy and field emission scanning electron microscopy and percentage of the ferrite phase in AISI 410 microstructure by using Clemex software were considered as process output responses. Results confirmed that by increasing the laser power and reducing the scanning speed, the surface hardness and the depth of hardness increase. It is also revealed the width of the hardened area increases by enhancing stand-off distance and reducing the laser power. Maximum hardness of 630 HV0.3 with 2.2 mm depth is obtained. Also, the furnace hardening heat treatment is compared with the laser hardening process. Microstructure, microhardness, and impact tests of the two processes are compared. Results showed that the hardness of the diode laser is 1.4 times the hardness of the furnace hardening heat treatment.
关键词： Microhardness deviation,Microhardness,AISI 410 martensitic stainless steel,Laser surface hardening,Diode laser
更新于2025-09-11 14:15:04