Use of both the diode and Er: YAG lasers in esthetic crown lengthening with the aid of digitally guided dual technique: 3 years follow-up.

OBJECTIVE: To explore the feasibility of the usage of digital guides in combination with low- and high-power lasers for the treatment of excessive gingival display, also known as "gummy smile". CLINICAL CONSIDERATIONS: Excessive gingival display due to altered passive eruption can affect patient's perception of their own esthetics and consequently have an impact on self-confidence. Therefore, the management of this condition should offer a predictable and stable long-lasting solution. To attain these objectives, digital planning emerges as a tool in optimizing the outcomes of crown lengthening surgery for this condition by enhancing precision through the use of surgical guides. Additionally, the usage of high- and low-powered lasers can provide a safe approach because of their tissue selective removal properties. CONCLUSIONS: The technique described showed satisfactory clinical results in the short- and long-term follow-up, leading to an improvement in patients' self-esteem. This approach integrates digital and laser technologies to deliver a surgical treatment characterized by precision, efficiency, and safety. CLINICAL SIGNIFICANCE: Digital dentistry has contributed to innovative dental procedures, as personalizing surgical guides for patients, assisting and guiding incisions of the gingival margins, as well as the extension of the osteotomy, during the procedures for increasing the clinical crown. Furthermore, smile esthetics are directly related to an individual's improved emotional and social quality of life.

A simplified mid-infrared anti-resonant chalcogenide fiber with fewest resonant peaks.

High-power laser delivery in the mid-infrared via hollow-core fibers is attractive, but it is too difficult to be fabricated using chalcogenide glasses. Here, we designed a mid-infrared hollow-core anti-resonant chalcogenide fiber (HC-ARCF) with a simplified Kagome cladding micro-structure for the first time. Then, the fiber was firstly fabricated through a precision mechanical drilling and pressured fiber drawing method. Ultra-thin walls of 2µm in the fiber lead to the fewest resonance peaks in the 2-5µm among all reported HC-ARCFs. All the fundamental mode, the second-order mode, tube mode and node mode in the fiber were excited and observed at 1550 nm. The power and spectral properties of the core and cladding of HC-ARCF are studied for the first time. The fiber can deliver high-power of 4.84 W without damage with core-coupling, while the threshold of the node in the cladding is only 3.5 W. A broadening of the output spectrum from 1.96 to 2.41µm due to the high nonlinearity at the node was successfully observed under short-pulse laser pumping at 2µm. The potentials of the fiber used for mid-infrared high-power laser delivery via core, or nonlinear laser generation via node, were thus demonstrated.

Histological implications of high-power laser use in the oral soft tissue lesions: a systematic review.

The objective of this study was to describe the histological artifacts caused by high-power laser use compared to cold scalpel surgery in oral soft tissue lesions. Clinical studies that evaluated and compared histological artifacts resulting from the use of high-power lasers and cold scalpels in oral soft tissue lesions biopsies were retrieved from seven databases and four grey literatures, up to July 2022. The risk of bias was investigated using the ROBINS-I tool. The certainty of the evidence was assessed using the Grading of Recommendations, Assessment, Development, and Evaluation approach. Seven studies were eligible for qualitative analysis. Based on the results obtained, those four studies had a low risk of bias, and three studies had an unclear risk of bias. The certainty of the evidence was classified as low. Limited evidence showed that epithelial artifacts such as loss of intraepithelial and subepithelial adhesions, accompanied by pyknotic, fusiform, and/or hyperchromic nuclei, were more common when a high-power laser device was used. Four articles reported that the use of high-power lasers did not interfere with the histopathological diagnosis of oral soft tissue lesions. Due to the heterogeneity of the data, a meta-analysis was not performed. Compared to the use of cold scalpels, histological artifacts, particularly those observed in epithelial tissue, are more common when high-powered lasers are used in oral lesions biopsies. The eligibility criteria and adequate indications of high-power lasers in different oral soft tissue lesion treatments must be respected to avoid tissue artifacts that impair precise histopathological diagnosis.

The use of 14/16Fr ureter access sheath for safe and effective management of large upper ureteral calculi.

OBJECTIVE: To evaluate the effectiveness of ureteroscopic lithotripsy for the management of large proximal ureteral stones > 10 mm using 14/16 Fr ureteral access sheath (UAS). MATERIALS AND METHODS: Patients' data from prospective database undergoing ureteroscopic laser lithotripsy with a use of 14/16Fr UAS were collected. All patients were pre-stented prior to the procedure. The fragmentation was performed with a semi-rigid ureteroscope using holmium laser energy with a power setting of 35 W (frequency-35 Hz; energy-1 J). Follow-up was scheduled at 4 weeks and 3 months postoperatively. RESULTS: In total 78 patients, 43 males and 35 females, were included in the study. The mean age of the patients was 59.5 ± 13.3 with a mean maximal stone diameter of 13.4 ± 2.1. The mean operative time was 35.7 ± 9.7 and the mean hospital stay was 2 ± 0.7 days. The primary SFR at 4 weeks was 73 patients (93.6%), while all 78 patients (100%) were stone free at 3-month follow-up, 2 of the patients receiving additional treatment. In total, 8 (10.2%) patients experienced Grade II complications. Intraoperative ureteral lesions were observed in 41 (52.6%) cases. Out of them 31 patients (39.7%) developed Grade 1, 8 patients (10.3%) Grade 2 and only 3 patients (2.6%) Grade 3 lesions. CONCLUSION: The use of 14/16Fr ureteral access sheath on pre-stented patients was associated with successful outcomes. A high stone-free rate of 93.6% was achieved at 4-week follow-up. The procedure was not associated with increased rate of postoperative complications and intraoperative ureteral injury.

Stone ablation rates using innovative pulse modulation technology: Vapor tunnel, virtual basket, and bubble blast. An in vitro experimental study.

INTRODUCTION AND OBJECTIVES: Virtual BasketTM , Bubble BlastTM , and Vapor TunnelTM are three laser pulse modulation technologies that modify the holmium: yttrium-aluminum-garnet (Ho:YAG) laser pulse transmission through the creation of bubbles emerging from the fiber tip with different effects on the target stone. The primary outcome of the current study was to test the stone ablation rates for the different pulse modulation modes, Virtual Basket, Bubble Blast, and Vapor Tunnel, using different power, energy, and frequency settings. MATERIALS AND METHODS: Quanta Cyber: Ho 150 WTM , a 365 µm PrecisionTM fiber, and hard and soft phantom BegoStonesTM were used in an in vitro experimental configuration in a saline bath. In the Virtual Basket mode, the combinations of power, energy and frequency were tested; 10 W = 0.5 J × 20 Hz, 10 W = 0.5 J × 20 Hz, 60 W = 1 J × 60 Hz and 60 W = 2 J × 30 Hz. In the Bubble Blast mode, the combinations, 12 W = 1.2J × 10 Hz, 60 W = 1.2J × 50 Hz and 60 W = 2 J × 30 Hz, were tested. Similarly, the combination of 10 W = 0.5 J × 20 Hz was tested with Vapor Tunnel mode. High-speed camera captures of the bubble formation and regular photographs of the fragmentation pattern were also taken for each mode. RESULTS: High power lithotripsy was faster and related to higher ablation rates. The Virtual Basket, Bubble Blast, and Vapor Tunnel modalities showed different ablation rates for the same energy and frequency settings. For hard stones, there was an improvement in the ablation rate using 60 W = 2 J × 30 Hz compared with 60 W = 1 J × 60 Hz and 60 W = 1.2 J × 50 Hz. The highest ablation rates were recorded using the Virtual Basket mode with the high-power settings of 2 J of energy and 30 Hz of frequency. CONCLUSIONS: The Virtual BasketTM pulse-modulation technology was related to the highest ablation rates for both hard and soft stones, compared to the Bubble BlastTM and the Vapor TunnelTM technologies in high-power and low-power lithotripsy respectively. For the same high power settings, higher energy seems to provide higher ablation rates.

Effects of different protocols of defocused high-power laser on the viability and migration of myoblasts-a comparative in vitro study.

The aim of the present study was to analyze for the first time the effect of photobiomodulation therapy (PBMT) using defocused high-power laser (DHPL) in myoblast cell line C2C12 viability and migration and compare them with low-power laser therapy. Cells were divided into 9 groups: Sham irradiation 10% fetal bovine serum (FBS); Sham irradiation 5%FBS; low-power laser 0.1 W; DHPL 810 1 W; DHPL 810 2 W; DHPL 980 1 W; DHPL 980 2 W; DHPL dual 1 W; DHPL dual 2 W. To simulate stress conditions, all groups exposed to irradiation were maintained in DMEM 5% FBS. The impact of therapies on cell viability was assessed through sulforhodamine B assay and on cells migration through scratch assays and time-lapse. Myoblast viability was not modified by PBMT protocols. All PBMT protocols were able to accelerate the scratch closure after 6 and 18 h of the first irradiation (p < 0.001). Also, an increase in migration speed, with a more pronounced effect of DHPL laser using dual-wavelength protocol with 2 W was observed (p < 0.001). In conclusion, the diverse PBMT protocols used in this study accelerated the C2C12 myoblasts migration, with 2-W dual-wavelength outstanding as the most effective protocol tested. Benefits from treating muscle injuries with PBMT appear to be related to its capacity to induce cell migration without notable impact on cell viability.

High amplification laser-pressure optic enables ultra-low uncertainty measurements of the optical laser power at kilowatt levels.

We present the first measurements of kilowatt laser power with an uncertainty less than 1 %. These represent progress toward the most accurate measurements of laser power above 1 kW at 1070 nm wavelength and establish a more precise link between force metrology and laser power metrology. Radiation pressure, or photon momentum, is a relatively new method of non-destructively measuring laser power. We demonstrate how a multiple reflection optical system amplifies the pressure of a kilowatt class laser incoherently to improve the signal to noise ratio in a radiation pressure-based measurement. With 14 incoherent reflections of the laser, we measure a total uncertainty of 0.26 % for an input power of 10 kW and 0.46 % for an input power of 1 kW at the 95 % confidence level. These measurements of absolute power are traceable to the SI kilogram and mark a state-of-the-art improvement in measurement precision by a factor of four.

Effect of high-power Nd:YAG laser on the growth of Staphylococcus aureus and Pseudomonas aeruginosa: an experimental study.

[Purpose] The aim of this study was to evaluate the effect of high-power Nd:YAG laser on Staphylococcus aureus and Pseudomonas aeruginosa bacterial growth. [Materials and Methods] Seven samples of S. aureus and seven samples of P. aeruginosa were prepared in the microbiology lab, one used as a control sample and the remaining six samples used as experimental samples, which were irradiated by a high-power laser (LASERSIX ME, 15W) with a total dose of 500 and 700 J. The primary measure was the semi-qualitative assessment of turbidity and bacterial count; the turbidity was assessed 24 h after laser application. [Results] There was a significant decrease in turbidity in all experimental samples of S. aureus and P. aeruginosa after 24 h of high-power laser application for 500 and 700 J and a significant decrease in the colony-forming unit (CFU) value in both types, and there were no significant differences in turbidity and CFU when comparing 500 and 700 J. [Conclusion] A high power Nd:YAG laser was found to be an effective modality for inhibition of S. aureus and P. aeruginosa growth.

Efficacy and safety of diode laser during circumvestibular incision for Le Fort I osteotomy in orthognathic surgery: a triple-blind randomized clinical trial.

The aim of this triple-blind randomized clinical trial was to evaluate the efficacy and safety of diode laser during circumvestibular incisions for Le Fort I osteotomy in orthognathic surgeries in comparison with conventional techniques using electrocautery and scalpel. Patients were randomly allocated to one of three groups based on the technique employed to perform incisions: diode laser, electrocautery, and scalpel. The parameters used to evaluate the efficacy and safety of diode laser were incision velocity, duration of surgery, bleeding rate, alterations in postoperative functions, pain, edema, wound clinical healing, and infection. Thirty patients were enrolled in the study (10 per group). Regarding bleeding, the incisions performed with diode laser promoted a lower bleeding rate compared with scalpel and electrocautery (p = 0.00). The diode surgical laser was effective during the incision procedure, but required a longer time to perform the incisions compared with the other techniques evaluated (p < 0.05). No statistically significant difference was detected between groups regarding total surgical time or other safety parameters (p > 0.05). Thus, diode laser proved to be effective and safer during circumvestibular incisions for Le Fort I osteotomy than conventional devices.

Compact and Highly Sensitive NO2 Photoacoustic Sensor for Environmental Monitoring.

A nitrogen dioxide (NO2) photoacoustic sensor for environmental monitoring was developed using a low-cost high-power laser diode emitting at 450 nm. A compact low-noise photoacoustic detection module was designed to reduce the sensor size and to suppress noise. A LabVIEW-based control system was employed for the sensor. The parameters of the sensor were studied in detail in terms of laser power and operating pressure. The linearity of the sensor response with laser power and NO2 concentration confirms that saturation does not occur. At atmospheric pressure, a 3σ detection limit of 250 ppt (part per trillion by volume) was achieved with a 1-s averaging time, which corresponds to the specific detectivity of 3.173 × 10-9 W cm-1 Hz-1/2. A 72 h outdoor continuous on-line monitoring of environmental NO2 was implemented to demonstrate the reliability and validity of the developed NO2 sensor.

High-power diode laser on management of drug-induced gingival overgrowth: Report of two cases and long-term follow-up.

BACKGROUND: Drug-induced gingival overgrowth (DIGO) is attributed mainly to the prolonged use of calcium channel blocking agents, anticonvulsants, and anti-calcineurin inhibitors . The management of DIGO depends on the severity of the disease and includes surgical intervention and plaque control. Compared to conventional surgical treatment, the recent literature data have shown that gingivectomy using a high-power laser (HPL) is a short and easy procedure, which results in minimal postoperative discomfort and greater patient accep- tance. OBJECTIVE AND METHODS: The purpose of this study was to report two cases of recurrent DIGO treated surgically using HPL (λ 808nm, 1.5W). RESULTS: Minimal bleeding and discomfort were observed during surgery, and patients reported no pain or bleeding after the procedure. After 1 year of follow-up, patients presented a minimal increase of gingival volume, indicating that laser technology can improve the efficiency and prognosis of DIGO. CONCLUSIONS: The HPL was able to preventing hemorrhage and improving the patient's collaboration with the treatment and quality of life.

High-power diode laser in the circumvestibular incision for Le Fort I osteotomy in orthognathic surgery: a prospective case series study.

The incisions during orthognathic surgery are classically performed with conventional scalpel or electrocautery. Considering that the high-power diode laser surgery may provide advantages when compared to conventional incision techniques, the current study aimed to present a prospective case series of patients submitted to circumvestibular incision for Le Fort I osteotomy. Ten patients with dentofacial deformities who underwent to rapid assisted maxillary expansion or bimaxillary orthognathic surgery were enrolled in the study. All incisions were performed by a single surgeon using an 808-nm diode laser, with an optical fiber of 600 µm, at a power of 2.5 W, in a continuous-wave mode. The performance of the incision was evaluated by incision velocity, bleeding, edema, secondary infection, clinical healing, and pain. The velocity of the incision ranged from 0.10 to 0.20 mm/s (mean 0.13 ± 0.03 mm/s). Considering bleeding during the soft tissue incision, all surgeries were classified as absent bleeding. All patients presented a clinical healing of the surgical wound in a period that range from 3 to 5 weeks and experienced swelling during the follow-up period. On average, approximately 50% of the swelling had resolved after the third postoperative week, and 28.8% of swelling remained after 2 months after the surgery. The pain decreased after 2 and 3 days, and 90.0% of the patients reported no pain after 7 postoperative days. High-power diode laser is effective and safety during circumvestibular incisions for Le Fort I osteotomy in orthognathic surgery decreasing bleeding, surgery time, pain, and edema after orthognathic surgery.

Fabrication of Refractive Index Tunable Coating with Moisture-Resistant Function for High-Power Laser Systems Based on Homogeneous Embedding of Surface-Modified Nanoparticles.

Moisture-resistant silicone coatings were prepared on the surface of potassium dihydrogen phosphate (KDP) crystal by means of spin-coating, in which hydrophobic-modified SiO2 nanoparticles were embedded in a certain proportion. The refractive index of such coating can be tuned arbitrarily in the range of 1.21⁻1.44, which endows the KDP optical component with excellent transmission capability as well as the moisture proof effect. A dual-layer anti-reflective coating system was obtained by covering this silicone coating with a porous SiO2 coating which is specially treated to enhance the moisture resistance. Transmittance of such a dual-layer coating system could reach 99.60% and 99.62% at 1064 nm and 532 nm, respectively, by precisely matching the refractive index of both layers. Furthermore, the long-term stability of this coating system has been verified at high humidity ambient of 80% RH for 27 weeks.

The use of a high-power laser on swine mitral valve chordae tendineae.

Worldwide, rheumatic fever remains a significant cause of mitral valve insufficiency. It is responsible for approximately 90 % of early childhood valvular surgeries in Brazil. Elongated or flail chordae are frequently responsible and require surgical correction. The purpose of this study was to analyze and compare the histological tissues of the mitral valve chordae and the mechanical resistance generated by the chordae, both with and without the application of a high-power laser. Twenty normal porcine mitral valve chordae were measured and divided randomly into the following two groups: control group (not subjected to a high-power laser) and laser group (subjected to photonic irradiation). Laser surgery was performed under controlled conditions, using following parameters: λ = 980-nm wavelength, power = 3 W, and energy = 60 J. A mechanical test machine was used in combination with a subsequent histological study to measure chordae tensile properties. A histological analysis demonstrated a typical collagen bundle arrangement in the control group; however, under a particular reached temperature range (48), the collagen bundles assumed different arrangements in the laser group. Significant reductions in the chordae tendineae lengths and changes in their resistance in the laser group were observed, as these chordae exhibited less rigid fibers. The chordae tendineae of normal porcine valves subjected to a high-power laser exhibited its length reduction and less stiffness compared to the control group. A histological analysis of the laser treatment specimens demonstrated differences in collagen bundle spatial organization, following slight changes into tissue temperature.

High-power Holmium:Yag lithotripsy in bladder urolithiasis: Is it safe and effective? A combined clinical and experimental study.

Objective: To evaluate the efficacy and safety of Holmium: Yttrium-Aluminum-Garnet (Ho:YAG) laser in bladder lithotripsy using high-power settings > 100 W. Materials and Methods: A combined experimental and clinical study was conducted. The Quanta Cyber: Ho 150 with a 550 µm Quanta optical fiber was utilized in all set-ups. Ablation rates for soft and hard artificial stones were tested in vitro using 100 W and 20 W power settings. In the experiment, a porcine bladder was used. The optical fiber was inserted through a rigid cystoscope, whilst a K-type thermocouple was inserted in the bladder dome. The tested high-power settings were 152 W, 120 W and 105 W. In every trial, the lasing time was over 60 s. In the clinical study, 35 patients underwent transurethral high-power bladder lithotripsy. Laser settings were set between 100 W and 150 W. Results: Stone mass (stone weight) was significantly lower after stone ablation independently of the stone type or the laser settings. Significantly higher mass decrease and ablation rate were detected in high-power compared to low-power settings. In the experiment, the highest temperature recorded was 32°C at 152 W. At 120 W and 105 W, the peak temperatures didn't reach 30°C. In the clinical study, a stone-free rate of 100% and a mean operative time of 43 ± 18 min were reported. All patients stayed in the hospital for one day except for one who presented minor hematuria. Additional complications did not occur. Conclusion: Ho:YAG laser lithotripsy > 100 W is an effective, fast and safe modality for the treatment of bladder calculi.

Effectiveness of High-Power Laser Therapy via Shear Wave Speed Analysis on Pain and Functioning in Patients with Lateral Epicondylitis: A Proof-of-Concept Study.

Background: Lateral epicondylitis (LE) causes lateral elbow pain due to the overuse of the common extensor tendon. Several therapies have been proposed for pain relief and functional recovery, including physical therapy, minimally invasive injection approaches, and physical agent modalities such as laser therapy. Methods: Our study evaluates the impact of high-power laser therapy (HPLT) on pain and functioning. The HPLT protocol consists of 10 daily sessions using a LASERIX PRO device. The healthy elbow of each participant was also considered as a control group. The outcomes assessed were the Numerical Rating Scale (NRS) for pain, QuickDASH questionnaire for functionality, and shear wave velocity (SWS) through ultrasonography. Assessments were conducted at baseline (T0), post-treatment (T1), and 2-week follow-up (T2). Results: Sixteen participants (81.2% male, mean age 40.4 ± 5.53 years) completed the study. Post-treatment, pain significantly decreased (NRS: T0 6.13 ± 0.96; T1 2.75 ± 1.69; p < 0.001), functionality improved (QuickDASH: T0 69.88 ± 10.75; T1 41.20 ± 3.78; p < 0.001), and shear wave velocity increased (SWS (m/s): T0 1.69 ± 0.35; T1 2.56 ± 0.36; p < 0.001). Conclusions: At the 2-week follow-up, pain relief was maintained, and shear wave velocity showed no further significant change. Shear wave velocity assessments might be considered a useful diagnostic tool. However, further research is needed to support the role of HPLT and shear wave velocity in the rehabilitation management of LE.

Multicentric evaluation of high and low power lasers on RIRS success using propensity score analysis.

In this study, we aimed to evaluate the effect of HPL on different parameters by different centers and urologists. While doing this, we evaluated different parameters by comparing HPL(High Power laser) and LPL(Low-power laser). This is an observational, retrospective, comparative, multicentric study of prospectively organised database. A total of 217 patients who underwent RIRS for kidney stones smaller than 2 cm in three different centers were included in the study. The patients were divided into two groups; LPL used (Group1, n:121 patients) and HPL used (Group2, n:96). Propensity score matching was done in the data analysis part. After matching, a total of 192 patients, 96 patients in both groups, were evaluated. There was no difference between the groups regarding age, gender, stone side, and stone location. The stone-free rate on the first day was 80.3% in Group 1, it was 78.1% in Group 2 (p = 0.9). In the third month, it was 90.7% in Group 1 and 87.5% in Group 2 (p:0.7).Hospitalization duration was significantly higher in Group 1. (2.35 ± 2.27 days vs. 1.42 ± 1.10 days; p < 0.001).The operation duration was 88.70 ± 29.72 min in Group1 and 66.17 ± 41.02 min in Group2 (p < 0.001). The fluoroscopy time (FT) was 90.73 ± 4.79 s in Group 1 and 50.78 ± 5.64 s in Group 2 (p < 0.001). Complications according to Clavien Classification, were similar between the groups(p > 0.05). According to our study similar SFR and complication rates were found with HPL and LPL. In addition, patients who used HPL had lower operation time, hospital stay, and fluoroscopy time than the LPL group. Although high-power lasers are expensive in terms of cost, they affect many parameters and strengthen the hand of urologists thanks to the wide energy and frequency range they offer.

Spectral Failsafe System of High-Power Laser Using Dual Fiber Bragg Gratings.

Phase-modulated (PM) spectral failsafe systems are necessary to promptly terminate amplification processes following accidental seeding of a high-power laser chain with a non-PM pulse to prevent optical damage. In this work, we present a reliable spectral failsafe system that can indicate the presence or absence of sufficient PM light. This requirement is met by combining dual temperature-sensitive fiber Bragg gratings detection with high-speed RF amplitude comparisons. The failsafe trigger signal is generated when the spectral power at the peak sideband exceeds that at the center. The spectral failsafe system has the ability to distinguish between adequate and inadequate PM pulses, and it exhibits significant robustness in pulse width, TEC temperature drift, and DFB wavelength drift in experiments, making it valuable for safe high-power laser operations and providing a useful reference for other detection system designs.

Surface Cleanliness Maintenance with Laminar Flow Based on the Characteristics of Laser-Induced Sputtering Particles in High-Power Laser Systems.

In high-power laser systems, the primary cause of contamination of optical components and degradation of spatial cleanliness is laser-induced sputtering of particles. To mitigate this problem, laminar flow is frequently utilized to control the direction and transport of these particles. This study characterizes the properties of laser-induced sputtering particles, including their flying trend, diameter range, and velocity distribution at varying time intervals. A time-resolved imaging method was employed to damage the rear surface of fused silica using a 355 nm Nd: YAG pump laser. The efficacy of laminar flow in controlling these particles was then assessed, with a particular focus on the influence of laminar flow direction, laminar flow velocity, particle flight height, and particle diameter. Our results indicate that the optimal laminar flow velocity for preventing particle invasion is highly dependent on the maximum particle attenuation distance (or safety distance), which can vary by up to two orders of magnitude. Furthermore, a laminar flow velocity of 0.5 m/s can effectively prevent particle sedimentation. Future research will aim to optimize laminar flow systems based on these findings to achieve high surface cleanliness in high-power laser systems with minimal energy consumption.