Search Results (95)

LiTaO₃ crystals doped with Cr³⁺ and Nd³⁺ ions are promising for developing active nonlinear laser media. In this work, the defect structure of LiTaO₃ crystals, including those doped with Cr³⁺ and Nd³⁺, is examined. X-ray patterns of all six investigated LiTaO₃:Cr:Nd crystals are identical and correspond to a highly perfect structure. Using optical microscopy, the presence of defects of various shapes, microinhomogeneities, and lacunae was revealed. The optical absorption and Raman scattering spectra of a series of nonlinear, optical, double-doped LiTaO₃:Cr³⁺:Nd³⁺ (0.06 ≤ [Cr³⁺] ≤ 0.2; 0.2 ≤ [Nd³⁺] ≤ 0.45 wt%) crystals showed that at concentrations of doping Cr³⁺ ions less than 0.09 wt% and Nd³⁺ ions less than 0.25 wt%, the crystal structure is characterized by a low level of defects, and the optical transmission spectra characterized by narrow lines corresponding to electron transitions in Nd³⁺ ions. In this case, for the radiative transition in the cation sublattice, the existence of three nonequivalent neodymium centers is observed, and for the radiative transition, two nonequivalent centers are observed. IR absorption spectroscopy in the OH⁻-stretching vibration range revealed two main spectral regions: 3463–3465 cm⁻¹, associated with stoichiometry changes, and 3486–3490 cm⁻¹, linked to complex defects such as (V^-_Li)-OH and (Ta⁴⁺_Li)-OH. A distinct low-intensity line at ~3504 cm⁻¹ was observed only in doped crystals, attributed to (Nd²⁺_Li)-OH defects that significantly distort the oxygen-octahedral clusters due to the larger ionic radius of Nd³⁺ compared to Ta⁵⁺. In contrast, Cr-related defects cause only minor distortions. The Klauer method indicated that the highest concentration of OH⁻-groups occurs in the LiTaO₃:Cr³⁺ (0.09 wt%):Nd³⁺ (0.25 wt%) crystal, where multiple complex defects are present. Full article

Objectives: This review examines the efficacy of each laser type in the field of periodontal surgery and analyzes published articles that focus on the use of lasers in periodontal surgery. Methods: Automatic and manual searches were made in 3 separate databases (PubMed, Embase, and Cochrane) with the aim of finding all published articles of the last 15 years up until December 2023 that describe the clinical manipulation of diode, erbium:yttrium-aluminum-garnet (Er:YAG), erbium, chromium: yttrium-scandium-gallium-garnet (Er,Cr:YSGG), neodymium yttrium-aluminum-garnet (Nd:YAG), and carbon dioxide (CO₂) lasers for periodontal surgical procedures in humans. Results: A total of 18 studies were selected for inclusion, all of which compared the usage of a laser type to conventional periodontal surgical techniques with their main follow-ups being in 3, 6, or 9 months. Conclusions: There are a variety of laser types, each with different settings and wavelengths, that can be applied to the established aspects of resective and regenerative periodontal surgeries. A significant majority of the publications, 10 of the 12 studies, that include diode lasers as an adjunctive show an improvement in clinical results compared to traditional surgical techniques alone, while 2 articles studied the Er:YAG laser and 1 article studied the Er,Cr:YSGG laser, with all 3 of them failing to completely test their therapeutic capabilities and indicating similar results to conventional surgery. The Nd:YAG laser was featured in 3 studies, with 1 study showing superior results for the laser group, another study showing the negative influence of the laser, and the 3rd study being inconclusive. The CO₂ laser was used in 1 study and showed better clinical results for the laser group. Diode lasers have been proven to produce additional therapeutic results, but there is a need for further investigation of erbium family lasers along with the Nd:YAG and CO₂ lasers, as the current provided literature contradicts their potential healing capabilities. Full article

Endodontic infections are characterized by complex polymicrobial communities residing within the intricate root canal system. Traditional chemomechanical methods frequently fail to achieve complete microbial eradication, especially in cases involving biofilm-forming and resistant species. This systematic review synthesizes current evidence on the molecular basis and antimicrobial efficacy of the neodymium-doped yttrium aluminum garnet (Nd:YAG) laser in root canal disinfection, particularly against polymicrobial infections. A comprehensive literature search was conducted in the PubMed, Embase, Scopus, and Cochrane databases in accordance with PRISMA 2020 guidelines. Experimental and preclinical studies evaluating the bactericidal properties of Nd:YAG laser therapy were included. The Nd:YAG laser demonstrated significant reductions in total microbial load through photothermal effects, including denaturation of proteins, disruption of cell membranes, and degradation of mixed-species biofilms. Although complete sterilization was not consistently achieved, its ability to penetrate dentinal tubules and target microbial consortia offers substantial adjunctive value. Standardization of laser parameters and further clinical studies are needed to validate these findings and establish Nd:YAG laser use in routine endodontic disinfection protocols. Full article

Rare earth elements (REEs), particularly neodymium (Nd), dysprosium (Dy), and praseodymium (Pr), are critical in the production of neodymium–iron–boron (NdFeB) magnets used in electronic devices, wind turbines, and electric vehicles. Due to the limited availability of these metals, their recovery from waste electronic equipment such as hard disk drives (HDDs) offers a promising solution. The aim of this study was to develop a method to grind NdFeB magnets obtained from the physical recycling of HDD. The recycled magnets were ground using a planetary mill. A review of the literature highlights the limitations of the currently used grinding methods, which require energy-intensive pretreatment processes, specialised conditions, or expensive equipment. This study employed a Fritsch planetary mill, tungsten carbide grinding balls, and ethanol as a grinding medium. NdFeB magnet samples (120 g) were ground for different durations (0.5 h–15 h) at a speed of 300 rpm, using a cyclic operating mode to minimise material heating. The resulting powders were analysed using a laser particle analyser, an optical microscope, and an X-ray diffractometer. The results enable the determination of optimal grinding parameters, achieving an average particle size (d₅₀) below 5 μm, which is essential for further processing and new magnet production. Finally, the economic and environmental aspects of producing the neodymium alloy were analysed. Full article

Lasers are widely employed in the treatment of melanocytic lesions. This scoping review evaluates 77 studies on the efficacy and safety of laser treatments for café-au-lait macules (CALMs), nevus of Ota (NOA), Becker’s nevus (BN), lichen planus pigmentosus (LPP), and other pigmented lesions. The Q-switched neodymium-doped yttrium aluminum garnet (Nd:YAG), particularly the 1064 nm, is the most frequently utilized laser, demonstrating strong efficacy for NOA and other dermal pigmentary disorders. Medium-wavelength lasers, including the Q-switched ruby and Alexandrite lasers, also show promise, though results vary based on lesion depth, skin type, and treatment protocols. Recurrence and adverse effects, including post-inflammatory hyperpigmentation (PIH) and hypopigmentation, are common, particularly in patients with darker skin tones. Future studies should standardize and optimize laser parameters across lesion types and skin tones, improve long-term efficacy, and prioritize inclusion of patients with diverse Fitzpatrick skin types to evaluate differential outcomes and promote equitable treatment efficacy. Full article

Random lasers (RLs) based on glasses and glass-ceramics doped with rare-earth ions (REI) deserve great attention because of their specific physical properties such as large thermal stability, possibility to operate at high intensities, optical wavelength tunability, and prospects to operate Fiber-RLs, among other characteristics of interest for photonic applications. In this article, we present a brief review of experiments with RLs based on tellurite and germanate glasses and glass-ceramics doped with neodymium (Nd³⁺), erbium (Er³⁺), and ytterbium (Yb³⁺) ions. The glass samples were fabricated using the melt-quenching technique followed by controlled crystallization to achieve the glass-ceramics. Afterwards, the samples were crushed to obtain the powder samples for the RLs experiments. The experiments demonstrated RLs emissions at various wavelengths, with feedback mechanisms due to light scattering at grain/air and crystalline/glass interfaces. The phenomenon of replica symmetry breaking was verified through statistical analysis of the RLs intensity fluctuations, indicating a photonic phase-transition (corresponding to the RL threshold) analogous to the paramagnetic-to-spin glass transition in magnetic materials. The various results reported here highlight the potential of glasses and glass-ceramics for the development of RLs with improved performance in terms of reduction of laser threshold and large lifetime of the active media in comparison with organic materials. Full article

Objective: Colorectal pulmonary metastasis is the most common resected metastatic disease of the lung. Pulmonary metastasectomy (PM) for colorectal oligometastases is a well-established intervention with curative intent. Local recurrence at the resection site in the lung is a problem, with an impact on survival. The use of a 1320 nm neodymium:yttrium aluminum garnet (Nd:YAG) laser causes the vaporization and coagulation at the resection line and thereby increases safety margins around the nodule. We aimed to evaluate the local recurrence rate after laser-assisted pulmonary metastasectomy (LPM) for colorectal metastases. Methods: We conducted a retrospective analysis of 49 patients treated with laser-assisted pulmonary metastasectomy for 139 metastatic nodules from colorectal cancer from 2010 to 2018. All nodules were resected using Nd:YAG 1320 nm laser, aiming for a safety margin of five mm. The minimum follow-up time after PM was 24 months. Results: Local intrapulmonary recurrence developed at 7 of the 139 (5.0%) resection sites in 5 of the 49 patients (10.2%). Microscopically incomplete resection was a significant risk factor for recurrence (p = 0.023). Larger nodule size (>12 mm) negatively impacted local recurrence (p = 0.024). Nodules larger or equal to 12 mm in size also lowered the patients’ probability of survival by 67.29% (HR: 0.3271, 95% CI: 0.1265–0.846, p = 0.018). Conclusions: The rate of local recurrence at the resection site after LPM for colorectal metastases is low. Complete resection is a positive predictor of survival without local recurrence. Microscopic complete resection with the addition of vaporization and coagulation at the resection margin seems to be sufficient to prevent local recurrence. However, larger nodules may require larger safety margins. Full article

Objectives: The aim of this article is to examine the effectiveness and capabilities of laser use in periodontal surgical therapy by analyzing the existing literature that focuses on laser use alone or as a supplement to the already existing periodontal surgical techniques, comparing it to conventional periodontal surgical therapy, with the intent to reach a better understanding of the efficiency and therapeutic potential of lasers in periodontal surgery. Methods: An electronic search of the PubMed, Embase, and Cochrane databases was performed between October 2023 and December 2023 to identify all of the articles published in the last 15 years and investigate information about the application of Diode, Erbium:yttrium–aluminum–garnet (Er:YAG), Carbon Dioxide (CO₂), and Neodymium yttrium–aluminum–garnet (Nd:YAG) lasers to surgical periodontal therapy in human trials. Results: The database search yielded 18 studies. All of the databases showed a clinical improvement in pocket depth (PD), clinical attachment level (CAL), gingival recession (GR), and bleeding on probing (BOP) in both the test and control groups, with results from five articles showing statistically better PD reduction in the laser group compared to the control group. CAL gain was statistically higher in the laser group in six articles, while one study indicated better PD and CAL results in the control group. Improved GR reduction with a laser was noted in two articles, while one article reported a negative influence from a laser in GR. BOP was significantly better with laser in one study, while the remaining two studies reported the same results as the control group. Conclusions: Laser application in resective surgery exhibits additional benefits to the already established techniques, while in regenerative surgery, more investigation is needed. Diode laser use in periodontal surgery is already widespread and shows clinical efficacy, while low-level laser therapy (LLLT) has an exceptional potential for a variety of applications, promoting better wound healing and less post-surgical complications. However, more trials and studies are needed to further examine the maximum efficiency of each laser type in periodontal surgical therapy. Full article

Objective: The aim of this systematic review was to evaluate the effectiveness and safety of various laser wavelengths for debonding orthodontic metal brackets compared to traditional plier-based methods. The primary outcomes assessed were enamel damage, pulp temperature changes, adhesive remnant index (ARI), and shear bond strength (SBS). Materials and Methods: In September 2024, an electronic search was performed across the PubMed, Web of Science (WoS), and Scopus databases, adhering to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines and the PICO framework. The initial search yielded 453 records. After eliminating 256 duplicates, 197 unique records were left for screening, which ultimately led to the qualification of 8 articles that met the inclusion criteria for both qualitative and quantitative analyses. The risk of bias in the articles was assessed by two independent reviewers. Results: The included studies demonstrated that laser-assisted debonding generally resulted in less adhesive residue on the enamel surface compared to conventional methods, as evidenced by the reductions in ARI scores reported in two studies. Temperature increases during laser use varied depending on the laser type and power settings. The Nd:YAG (neodymium-yttrium, aluminum, garnet) laser was found to cause significant temperature rises, posing a potential risk to pulp tissue, while the Er:YAG (erbium—yttrium, aluminum, garnet) and Er,Cr:YSGG (erbium, chromium—yttrium, scandium, gallium, garnet) lasers produced only negligible increases in pulp temperature. SBS comparisons revealed no significant differences between the laser-assisted and traditional debonding methods. Additionally, diode lasers demonstrated the potential to minimize enamel damage, particularly when operated at lower power settings. Four publications were assessed as high quality (low risk of bias), and another four as moderate quality (average risk of bias). Conclusions: In conclusion, laser-assisted orthodontic metal bracket debonding, when conducted with appropriately calibrated parameters, is a safe method for preserving tooth tissue. However, its advantages appear to be minimal compared to conventional plier-based methods, highlighting the need for further research to justify its broader clinical application. Full article

Background: Trigeminal neuralgia (TN) is a disease that causes severe pain that can seriously affect the quality of life. This study aimed to compare the effectiveness of two different low-level laser therapies (LLLT) as alternatives to medical treatment to reduce pain and improve the quality of life in patients with TN. Methods: A total of 45 patients were randomly divided into 3 groups. In the first group, a new-generation diode laser (GRR laser) was applied at predetermined points in the trigeminal nerve line. In the second group, a low-level neodymium-doped yttrium aluminum garnet (Nd:YAG) laser was applied along the affected nerve line. The placebo group received the same protocol with a Nd:YAG laser without the device switched on. The scores were recorded pre- and post-treatment using the Brief Pain Inventory-Facial (BPI-facial) scale. Results: A statistically significant difference was found between the pre- and post-treatment values of all four variables in the GRR laser, Nd:YAG laser, and placebo groups. When the post-treatment values were compared, statistically significant differences were found between the groups in pain frequency, pain intensity, and interference in facial-specific activities, but no differences were found in general activities. Conclusions: Both LLLTs can be considered alternative treatment modalities for TN, but the GRR laser treatment was more effective than the Nd:YAG laser treatment in reducing pain and improving the quality of life in patients with TN. Full article

Background: Oral microbiota comprises a wide variety of microorganisms. The purpose of this study was to evaluate the effects of Nd:YAG laser with a 1064 nm wavelength on the in vitro growth of Candida albicans, Candida glabrata, and Streptococcus mutans clinical strains, as well as their biofilm. The study also aimed to determine whether the parameters recommended for photobiomodulation (PBM) therapy, typically used for tissue wound healing, have any additional antibacterial or antifungal effects. Material and Methods: Single- and dual-species planktonic cell solution and biofilm cultures of Streptococcus mutans, Candida albicans, and Candida glabrata were irradiated using an Nd:YAG laser (LightWalker; Fotona; Slovenia) with a flat-top Genova handpiece. Two test groups were evaluated: Group 1 (G-T1) exposed to low power associated parameters (irradiance 0.5 W/cm²) and Group 2 (G-T2) with higher laser parameters (irradiance 1.75 W/cm²). Group 3 (control) was not exposed to any irradiation. The lasers’ effect was assessed both immediately after irradiation (DLI; Direct Laser Irradiation) and 24 h post-irradiation (24hLI) of the planktonic suspension using a quantitative method (colony-forming units per 1 mL of suspension; CFU/mL), and the results were compared with the control group, in which no laser was applied. The impact of laser irradiation on biofilm biomass was assessed immediately after laser irradiation using the crystal violet method. Results: Nd:YAG laser irradiation with photobiomodulation setting demonstrated an antimicrobial effect with the greatest immediate reduction observed in S. mutans, achieving up to 85.4% reduction at the T2 settings. However, the laser’s effectiveness diminished after 24 h. In single biofilm cultures, the highest reductions were noted for C. albicans and S. mutans at the T2 settings, with C. albicans achieving a 92.6 ± 3.3% reduction and S. mutans reaching a 94.3 ± 5.0% reduction. Overall, the T2 settings resulted in greater microbial reductions compared to T1, particularly in biofilm cultures, although the effectiveness varied depending on the microorganism and culture type. Laser irradiation, assessed immediately after using the crystal violet method, showed the strongest biofilm reduction for Streptococcus mutans in the T2 settings for both single-species and dual-species biofilms, with higher reductions observed in all the microbial samples at the T2 laser parameters (p < 0.05) Conclusion: The Nd:YAG laser using standard parameters typically applied for wound healing and analgesic effects significantly reduced the number of Candida albicans; Candida glabrata; and Streptococcus mutans strains. Full article

Rare earth elements (REEs) hold significant industrial, scientific, and modern technological worth. This study focused on detecting and quantifying REEs in various geological ore samples. These samples were collected from different REE-bearing locations recommended by geological experts. The analysis was conducted using laser-induced breakdown spectroscopy (LIBS) and laser ablation time-of-flight mass spectrometry (LA-TOF-MS). In this work, LIBS methodology was employed using three different configurations: standard LIBS, LIBS with an applied magnetic field, and LIBS with both an applied magnetic field and target sample heating within an optimal temperature range. Elements from the REE group, specifically lanthanum (La), cerium (Ce), and neodymium (Nd), were identified and quantified. To detect, quantify, and validate the results from LIBS and LA-TOF-MS, we utilized an array of analytical techniques—Energy-Dispersive X-ray Spectroscopy (EDX), Energy-Dispersive X-ray Fluorescence Spectrometer (ED-XRF), and Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES). Interestingly, the quantitative results for REEs (La, Ce, and Nd) in the ore samples obtained using the LIBS technique with various configurations were found to be in agreement with those from LA-TOF-MS, EDX, XRF, and ICP-OES. In addition, LIBS enables detailed microchemical imaging, allowing the map of the spatial distribution of elements within the mineral–ore matrix. The high-resolution microscale elemental mapping of REEs was accomplished using the emission lines Ce (II) at 446.0 nm, La (II) at 492.1 nm, and Nd (II) at 388.8 nm. By integrating multiple analytical techniques, our study enabled the construction of a complete elemental distribution map, providing new insights into the geochemical processes and mineral composition of rare earth ores, while advancing geochemistry and contributing valuable data for rare earth resource exploration. Full article

Neodymium-doped yttrium vanadate random lasers have presented exceptional efficiency and output power at the 1064 nm emission wavelength. However, emission at 1340 nm has not yet been observed for these random lasers, even though regular bulk lasers have presented many impressive properties in this infrared region. Here, we present a dual-emission Nd³⁺:YVO₄ pellet random laser, which emits at both 1064 nm and 1340 nm using a 585 nm pump wavelength, showing a new property corresponding to a much lower laser threshold at 1340 nm than with 1064 nm. Full article

Background and Objectives: The 1444 nm wavelength Neodymium:Yttrium–Aluminum–Garnet (Nd:YAG) laser treatment is an efficient method for treating axillary osmidrosis (AO); however, it has a relatively low treatment persistence. To address this issue, we performed integrated liposuction surgery with a laser to treat AO and compared the results with those of a group treated only with a laser. Materials and Methods: This study compared the outcomes of AO treatment between the two groups up to six months postoperatively. The first group of 18 patients underwent laser treatment alone, and the second group of 12 patients underwent integrated liposuction surgery in addition to laser treatment. Outcomes were assessed using the following variables: degree of malodor (DOM), sweating area, patient satisfaction, pain levels, and complications, such as burns, swelling, and contractures. Results: Compared to the laser-only group, the integrated liposuction group demonstrated significantly superior outcomes in terms of DOM (p = 0.002) and patient satisfaction (p = 0.006), as well as a reduction in the sweating area (p = 0.012). The pain rating was higher in the liposuction group, but the difference was not statistically significant (p = 0.054). Compared with the patients in the integrated liposuction treatment group, those in the laser treatment group exhibited a significantly higher number of burns under the axillae (p = 0.025). However, no significant differences were observed in the swelling or contracture between the groups. Conclusions: Integrated liposuction with laser therapy significantly improved treatment outcomes, including malodor, patient satisfaction, sweat test results, and decreased complication rates. Full article

The use of low-fluence picosecond (LFPS) 1064 nm neodymium-doped yttrium aluminum garnet (Nd:YAG) lasers, referred to as laser toning, is increasingly acknowledged as an effective treatment for pigmentation disorders in the Asian skin phenotype. This study aimed to conduct a comparative analysis on the effectiveness and safety of utilizing LFPS 1064 nm Nd:YAG lasers against picosecond 532 nm Nd:YAG lasers in treating pigmented lesions among Chinese patients. A retrospective photographic analysis and chart reviews were performed on 31 subjects exhibiting Fitzpatrick skin types III–VI who underwent LFPS 1064 nm Nd:YAG or picosecond 532 nm Nd:YAG treatments at a single tertiary center. Utilizing VISIA Complexion Analysis, comparative photographs were taken. Two independent physicians evaluated treatment efficacy using a visual analog scale (VAS) to assess the percentage of pigmentary clearance in standard photographs. Solar lentigines were the most prevalent pigmentary disorder, followed by post-inflammatory hyperpigmentation (PIH), nevus zygomaticus, melasma, freckles, and nevus of Ota. The clinical effectiveness of picosecond 532 nm and LFPS 1064 nm laser treatments proved comparable for lesions on the face, with mean VAS scores of 2.2 ± 1.1 and 1.8 ± 0.8, respectively. There were two cases of PIH in the picosecond 532 nm group, which resolved within one month. Overall, the LFPS 1064 nm laser demonstrates promise as a safe and efficient therapeutic modality for managing pigmented lesions in Chinese patients. Full article