Search Results (114)

The laser heterogeneous lap welding of nickel-plated steel and Cu sheets has been investigated in this study. The YAG (Yttrium-Aluminum-Garnet) laser beam only penetrates the upper Ni-plated steel sheet and cannot weld the bottom Cu sheet due to the low absorption coefficient of the YAG laser beam. Incorporating a blue-light and fiber laser into the coaxial laser beam significantly improves the quality of the weld fusion zone. The fiber laser beam can penetrate the upper nickel-plated steel sheet, and the blue-light laser beam can melt the bottom copper sheet. Introducing the blue-light laser to the coaxial laser beams overcomes the low reflectivity of the bottom copper sheet. The fiber/blue-light coaxial laser continuous welding can achieve the best integrity and defect-free welding. It shows potential in the mass production of the next generation of lithium batteries. 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

Background and Objectives: Conventional methods for removing cemented fixed prosthetic restorations (FPRs) are unreliable and lead to unsatisfactory outcomes. At their best, they allow the tooth to be saved at the expense of a laborious process that also wears down rotating tools and handpieces and occasionally results in abutment fractures. Restorations are nearly never reusable in any of these situations. Erbium-doped yttrium-aluminum-garnet (Er:YAG) and erbium-chromium yttrium-scandium-gallium-garnet (Er,Cr:YSGG) lasers casafely and effectively remove FPRs, according to scientific studiesre. This study sets out to examine the impact of Er:YAG laser radiation on the debonding of different ceramic restorations, comparing the behavior of various ceramic prosthetic restoration types under laser radiation action and evaluating the integrity of prosthetic restorations and dental surfaces exposed to laser radiation. Materials and Methods: The study included a total of 16 removed teeth, each prepared on opposite surfaces as abutments.y. Based on the previously defined groups, four types of ceramic restorations were included in the study: feldspathic (F), lithium disilicates (LD), layered zirconia (LZ), and monolithic zirconia (MZ). The thickness of the prosthetic restorations was measured at three points, and two different materials were used for cementation. The Er:YAG Fotona StarWalker MaQX laser was used to debond the ceramic FPR at a distance of 10 mm using an R14 sapphire tip with 275 mJ, 20 Hz, 5.5 W, with air cooling (setting 1 of 9) and water. After debonding, the debonded surface was visualized under electron microscopy. Results: A total of 23 ceramic FPRs were debonded, of which 12 were intact and the others fractured into two or three pieces. The electron microscopy images showed that debonding took place without causing any harm to the tooth structure. The various restoration types had the following success rates: 100% for the LZ and F groups, 87% for the LD group, and 0% for the MZ group. In terms of cement type, debonding ceramic FPRs cemented with RELYX was successful 75% of the time, compared to Variolink DC’s 69% success rate. Conclusions: In summary, the majority of ceramic prosthetic restorations can be successfully and conservatively debonded with Er:YAG radiation. 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

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

Background: Composite resin veneers have gained popularity due to their affordability and minimally invasive application as biomimetic restorations. However, long-term clinical challenges, such as discoloration, wear, and reduced fracture resistance, necessitate their replacement over time. Ceramic veneers, particularly feldspathic and lithium disilicate, offer superior esthetics and durability, as demonstrated by studies showing their high survival rates and enamel-preserving preparation designs. However, while ceramic veneers survive longer than composite resin veneers, ceramic veneers may need to be removed and replaced. Reports vary for using Er:YAG (erbium-doped yttrium aluminum garnet) lasers for the removal of existing veneers. Methods: A review was conducted to evaluate the effectiveness of removing restorative materials with an Er:YAG laser. A clinical study was included, highlighting the conservative removal of aged composite resin veneers using the Er:YAG laser. This method minimizes enamel damage and facilitates efficient debonding. Following laser application, minimally invasive tooth preparation was performed, and feldspathic porcelain veneers were bonded. Results: The review showed positive outcomes whenever the Er:YAG laser was used. In the case study, after a 3-year follow-up, the restorations exhibited optimal function and esthetics. Conclusions: Laser-assisted debonding provides a safe and predictable method for replacing failing composite veneers with ceramic alternatives, aligning with contemporary biomimetic principles. Full article

Background: The quest for minimally invasive disinfection in endodontics has led to using Erbium:Yttrium-Aluminum-Garnet (Er:YAG) lasers. Conventional approaches may leave bacterial reservoirs in complex canal anatomies. Er:YAG’s strong water absorption generates photoacoustic streaming, improving smear layer removal with lower thermal risk than other laser systems. Methods: This systematic review followed PRISMA 2020 guidelines. Database searches (PubMed/MEDLINE, Embase, Scopus, Cochrane Library) identified studies (2015–2025) on Er:YAG laser-assisted root canal disinfection. Fifteen articles met the inclusion criteria: antibacterial efficacy, biofilm disruption, or smear layer removal. Data on laser settings, irrigants, and outcomes were extracted. The risk of bias was assessed using a ten-item checklist, based on guidelines from the Cochrane Handbook for Systematic Reviews of Interventions. Results: All studies found Er:YAG laser activation significantly improved root canal disinfection over conventional or ultrasonic methods. Photon-induced photoacoustic streaming (PIPS) and shock wave–enhanced emission photoacoustic streaming (SWEEPS) yielded superior bacterial reduction, especially apically, and enabled lower sodium hypochlorite concentrations without sacrificing efficacy. Some research indicated reduced post-operative discomfort. However, protocols, laser parameters, and outcome measures varied, limiting direct comparisons and emphasizing the need for more standardized, long-term clinical trials. Conclusions: Er:YAG laser-assisted irrigation appears highly effective in biofilm disruption and smear layer removal, supporting deeper irrigant penetration. While findings are promising, further standardized research is needed to solidify guidelines and confirm Er:YAG lasers’ long-term clinical benefits. 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

In this study, ion-beam-induced luminescence with 2 MeV H⁺ was used to excite YAG single crystals at different temperatures. Under several constant temperatures, the luminescence intensity of Yb²⁺ monotonically decreases with increasing fluence, eventually reaching approximately 35% of the initial intensity at a fluence of 3.5 × 10¹⁴ cm⁻². The nonmonotonic evolution behavior of Yb²⁺ luminescence intensity with temperature can be effectively described by the intermediate-state model under consecutive temperature variations. The presence of an intermediate state may be the primary cause of the negative thermal quenching of Yb²⁺ luminescence. Yb²⁺ luminescence intensity decreased to 60% of the initial intensity when the temperature was continuously varied in the 100–300 K range, although the peak position remained rather stable. The luminescence of Yb²⁺ exhibits good radiation resistance and thermal stability in the experimental temperature range. 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

Introduction: In recent years, erbium-doped yttrium aluminum garnet (Er:YAG) and erbium, chromium/yttrium–scandium–gallium–garnet (Er,Cr:YSGG) lasers have been introduced as another possibility to perform less-invasive flapless (FL) crown-lengthening (CL) procedures. Objectives: The aim of this review is to describe the outcomes and complications of this approach. Materials and methods: A literature review was conducted to retrieve clinical studies and case reports that analyze different variables related to laser-assisted flapless crown lengthening and report their outcomes in terms of gingival margin level stability (GMLS), and postoperative complications. Results: A total of five studies were included in the final qualitative analysis; two of them were randomized controlled trials (RCTs) and the rest were case reports. The common variable measured in all studies was the GMLS, finding good stability in the FL groups at 3 months follow-up, but more tissue rebound was observed in patients with the thick biotype. Other variables were reported in different articles as the plaque index (PI), gingival index (GI), bone margin level, biotype, bleeding on probing (BP), probing depth (PD), and postoperative pain by the numeric rating scale (NRS). Discussion: There are a wide range of heterogenous clinical variables used to evaluate outcomes, as well as variations in the type of laser used and its parameters in terms of the applied technique. However, most analyzed studies showed better GMLS for the flapless technique, as well as less postoperative inflammation. Conclusions: The included studies showed promising clinical outcomes in the FL laser-assisted CL groups concerning GMLS at the 3-month postoperative period. However, more RCTs are needed with respect to fixed laser parameters and patient biotype selection to reach a definitive clinical protocol. Full article

A method for measuring light intensity at different depths of a strongly scattering medium (composite films of photoluminophore YAG:Ce³⁺) has been developed. The depth at which a collimated light source is converted into an isotropic radiation source was determined. The volumetric absorption coefficient of luminophore powder microparticles, which are suspended in the suspension, was measured. The concentration of trivalent cerium ions (Ce³⁺) in the powder particles of composite films was determined. It is shown for the first time that bulk light absorption increases the number of absorbed light quanta in a particle by a factor of six, without increasing the concentration of cerium ions in the particle. 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

In this in vitro study, we aimed to evaluate and compare the antibacterial efficacy of a novel erbium-doped yttrium aluminum garnet laser modality, shock wave enhanced emission of photoacoustic streaming (SWEEPS), ultrasonically activated irrigation (UAI), and single needle irrigation (SNI) against old bacterial biofilm. A two-week-old Enterococcus faecalis biofilm was cultivated on transversal dentinal discs made from the middle third of the roots of single-rooted, single-canal premolars. Biofilm growth was confirmed using scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM). The dentine samples were randomly distributed into three experimental groups and one control group based on the irrigation protocol used: Group 1, SWEEPS; Group 2, UAI; and Group 3, SNI. The root canals were irrigated with a 3% sodium hypochlorite solution. Antibacterial efficacy was evaluated quantitatively through bacterial culture and qualitatively through CLSM and SEM. Both SWEEPS and UAI demonstrated a statistically significant reduction in Enterococcus faecalis colony-forming units (CFUs) (p < 0.001), while SNI did not show a statistically significant reduction (p = 0.553). No significant difference was observed between the efficacy of SWEEPS and UAI (p > 0.05). The SWEEPS and UAI techniques were equally effective in eliminating mature E. faecalis biofilm. Full article