Effects of Two Remineralizing Agents in Combination with Er:YAG and CO2 Laser Irradiation on Microhardness of Demineralized Enamel: A Preliminary In Vitro Study.

Objectives: This study assessed the effects of two remineralizing agents namely MI Paste Plus containing casein phosphopeptide amorphous calcium phosphate fluoride (CPP-ACFP) and Remin Pro containing hydroxyapatite, fluoride and xylitol (HFX) with/without erbium-doped yttrium aluminium garnet (Er:YAG) and CO2 laser irradiation on demineralized enamel microhardness. Materials and Methods: In this in vitro study, 70 sound human premolars were mesiodistally sectioned, demineralized at a pH of 4.6 for 8 hours, and randomly divided into 7 remineralization groups (n=10): of (I) MI Paste Plus (CPP-ACFP), (II) Remin Pro (HFX), (III) MI Paste Plus+CO2 laser (0.7 W power, 50 Hz), (IV) Remin Pro+CO2 laser, (V) MI Paste Plus+Er:YAG laser (1 W power, 10 Hz), (VI) Remin Pro+Er:YAG laser, and (VII) negative control. The Vickers hardness number of specimens was then measured. The groups were compared by one-way ANOVA and Tukey's test (α=0.05). Results: The mean microhardness was 319.8±49.9, 325.3±44.6, 359.4±35.7, 296.4±33.7, 319.9±58.1, 358.9±28.4, and 240.0±41.6 kg/mm2 in groups 1 to 7, respectively. The difference in microhardness was significant among the groups (P<0.0001). Pairwise comparisons revealed significant differences in microhardness between all groups (P≤0.03) except between groups 1 and 2, 1 and 5, 2 and 5, and 3 and 6 (P>0.05). Conclusion: Both Remin Pro (containing HFX) and MI Paste Plus (containing CPP-ACFP) can cause enamel remineralization. MI Paste Plus+CO2 laser irradiation and Remin Pro+Er:YAG laser irradiation were significantly more effective than the application of each remineralizing agent alone.

The impact of different surface treatments on repair bond strength of conventionally, subtractive-, and additive-manufactured denture bases.

OBJECTIVE: This study aimed to examine the shear bond strength (SBS) of repair material to conventionally, subtractive-, and additive-manufactured denture bases after different surface treatments. MATERIALS AND METHODS: Disk-shaped test specimens (N = 300) were prepared from denture base materials produced by one conventional (Procryla), one subtractive (Yamahachi), and one additive (Curo Denture) method. The test specimens were randomly divided into five groups (n = 10) and exposed to a variety of surface treatments-Group A: no surface treatment; Group B: grinding with silicon carbide paper; Group C: sandblasting; Group D: erbium: yttrium-aluminum-garnet laser; and Group E: plasma. Repair was performed with autopolymerizing acrylic resin (Meliodent). Surface roughness analyses were performed with a profilometer. Scanning electron microscopy was used to examine one specimen from each subgroup. SBS was evaluated on a universal testing machine. Failure types were observed under a stereomicroscope. RESULTS: Surface roughness values were significantly higher in all test materials in Group D than in the other groups (p < 0.001). For conventional resin, the SBS values were higher in Group C than in Groups A, D, and E (p < 0.001). For CAD/CAM material, Groups B and C had significantly greater SBS increases compared with Group E (p < 0.001). For 3D material, Group D showed higher SBS than all groups except Group C (p < 0.001). CONCLUSIONS: For SBS, sandblasting was most effective in the conventional group, whereas laser treatment was the most effective in the additive-manufactured group. For the subtractive group, surface treatments other than plasma exhibited similar SBS. CLINICAL SIGNIFICANCE: In repairing fractured prostheses, any degree of roughening suitable for the material content may provide an SBS benefit.

Comparative Evaluation of Er: YAG Laser, Diode Laser, and Novamin Technology for Dentinal Tubule Occlusion: An In-Vitro Scanning Electron Microscope (SEM) and Energy Dispersive X-Ray Analysis (EDX) Study.

BACKGROUND: Dentinal hypersensitivity is a brief and painful oral condition that is characterized by an abrupt shooting sensation. Stimulation occurs when hot, cold, sweet, or sour food comes into contact with exposed dentinal tubules. The present study used a scanning electron microscope (SEM) and energy dispersive X-ray analysis (EDX) to investigate the efficacy of Er: YAG, 810 nm diode LASER, and NovaMin Technology in obstructing dentinal tubules. MATERIAL AND METHODS: We extracted the outer layers of 30 human teeth to expose the tubules and then treated the surfaces with 17% ethylenediaminetetraacetic acid (EDTA) to create an etched effect. Three cohorts were created from the portions. Group A was subjected to the application of Erbium:Yttrium-Aluminum-Garnet (Er: YAG) laser with a power output of 2W in the non-contact mode for 1 minute. Group B was subjected to the application of an 810nm diode laser with a power output of 1W in continuous mode for 30 seconds. Group C was subjected to the application of NovaMin paste, which contains a 927 ppm fluoride content. Following the therapy, occluded dentinal tubules were analyzed using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) for both quantitative and qualitative examination. The data analysis was conducted using a one-way analysis of variance (ANOVA) and Tukey's test, with a significance threshold of 0.05. RESULTS: The average percentages of complete blockage of dentinal tubules in Groups A, B, and C were evaluated using the number of entirely unobstructed dentinal tubules at magnifications of 2000X (F = 3.05, p = 0.064), 5000X (F = 5.33, p = 0.011), and 10000X (F = 8.63, p = 0.001). The count of partially open dentinal tubules seen at magnifications of 2000X, 5000X, and 10000X was F = 10.15 (P < 0.001), F = 5.97 (p = 0.007), and F = 2.12 (p = 0.140) accordingly. CONCLUSION: NovaMin technology has demonstrated more effectiveness in blocking dentinal tubules compared to 810nm diodes and Er: YAG lasers.

Lasing from a Large-Area 2D Material Enabled by a Dual-Resonance Metasurface.

Semiconducting transition metal dichalcogenides (TMDs) have gained significant attention as a gain medium for nanolasers, owing to their unique ability to be easily placed and stacked on virtually any substrate. However, the atomically thin nature of the active material in existing TMD lasers and the limited size due to mechanical exfoliation presents a challenge, as their limited output power makes it difficult to distinguish between true laser operation and other "laser-like" phenomena. Here, we present room temperature lasing from a large-area tungsten disulfide (WS2) monolayer, grown by a wafer-scale chemical vapor deposition (CVD) technique. The monolayer is placed on a dual-resonance dielectric metasurface with a rectangular lattice designed to enhance both absorption and emission, resulting in an ultralow threshold operation (threshold well below 1 W/cm2). We provide a thorough study of the laser performance, paying special attention to directionality, output power, and spatial coherence. Notably, our lasers demonstrated a coherence length of over 30 µm, which is several times greater than what has been reported for 2D material lasers so far. Our realization of a single-mode laser from a CVD-grown monolayer presents exciting opportunities for integration and the development of real-world applications.

Linearly Polarized Broadband Emission and Multiwavelength Lasing in Solution-Processed Quantum Dots.

A miniature laser with linear polarization is a long sought-after component of photonic integrated circuits. In particular, for multiwavelength polarization lasers, it supports simultaneous access to multiple, widely varying laser wavelengths in a small spatial region, which is of great significance for advancing applications such as optical computing, optical storage, and optical sensing. However, there is a trade-off between the size of small-scale lasers and laser performance, and multiwavelength co-gain of laser media and multicavity micromachining in the process of laser miniaturization remain as significant challenges. Herein, room-temperature linearly polarized multiwavelength lasers in the visible and near-infrared wavelength ranges are demonstrated, by fabricating random cavities scattered with silica in an Er-doped Cs2Ag0.4Na0.6In0.98Bi0.02Cl6 double-perovskite quantum dots gain membrane. By regulating the local symmetry and enabling effective energy transfer in nanocrystals, multiwavelength lasers with ultralow thresholds are achieved at room temperature. The maximum degree of polarization reaches 0.89. With their advantages in terms of miniaturization, ultralow power consumption, and adaptability for integration, these lasers offer a prospective light source for future photonic integrated circuits aimed at high-capacity optical applications.

A Modified Approach for Preventing Anterior Glottic Web Formation Using Mitomycin C in Bilateral Vocal Fold Lesions.

Objectives: Laryngeal keel insertion, mucosal suture, application of mitomycin-C (MMC), and staged operations are approaches to prevent the anterior glottic web, but there are limitations. Our study suggests a modified approach to prevent the formation of an anterior glottic web. Methods: This retrospective single-institution tertiary center study (N = 23) involved the simultaneous removal of bilateral vocal fold lesions with topical MMC application. If exudate was identified after 4 to 6 weeks, second laryngomicroscopic surgery (LMS) was performed to remove it with topical MMC application. Extent of anterior glottic web was measured as a percentage of the total length of the membranous vocal fold. Results: After the initial surgery, 18 patients recovered without anterior web or fibrin exudate. Thick exudate was observed in 5 patients. After the second LMS, all patients showed improvement and did not develop anterior web. Conclusion: This modified method has been developed to prevent the anterior glottic web without complications.

Creating realistic anterior segment optical coherence tomography images using generative adversarial networks.

AIMS: To develop a generative adversarial network (GAN) capable of generating realistic high-resolution anterior segment optical coherence tomography (AS-OCT) images. METHODS: This study included 142 628 AS-OCT B-scans from the American University of Beirut Medical Center. The Style and WAvelet based GAN architecture was trained to generate realistic AS-OCT images and was evaluated through the Fréchet Inception Distance (FID) Score and a blinded assessment by three refractive surgeons who were asked to distinguish between real and generated images. To assess the suitability of the generated images for machine learning tasks, a convolutional neural network (CNN) was trained using a dataset of real and generated images over a classification task. The generated AS-OCT images were then upsampled using an enhanced super-resolution GAN (ESRGAN) to achieve high resolution. RESULTS: The generated images exhibited visual and quantitative similarity to real AS-OCT images. Quantitative similarity assessed using FID scored an average of 6.32. Surgeons scored 51.7% in identifying real versus generated images which was not significantly better than chance (p value >0.3). The CNN accuracy improved from 78% to 100% when synthetic images were added to the dataset. The ESRGAN upsampled images were objectively more realistic and accurate compared with traditional upsampling techniques by scoring a lower Learned Perceptual Image Patch Similarity of 0.0905 compared with 0.4244 of bicubic interpolation. CONCLUSIONS: This study successfully developed and leveraged GANs capable of generating high-definition synthetic AS-OCT images that are realistic and suitable for machine learning and image analysis tasks.

Prognostic outcome of cervical laser ablation using a holmium yttrium-aluminum-garnet (Ho:YAG) laser for the treatment of cervical intraepithelial neoplasia: A single-center retrospective study.

Objective: Although cervical conization is considered a standard treatment for cervical intraepithelial neoplasia (CIN) 2/3, laser ablation can compensate for the disadvantages of the former. CO2, semiconductor, and holmium yttrium-aluminum-garnet (Ho:YAG) lasers are applied in ablation, but no previous studies have shown the effectiveness of any of these techniques. Here, we retrospectively analyzed the application of the Ho:YAG laser in our hospital to verify its efficacy, and discussed the methods for optimal recurrence detection. Methods: We evaluated the recurrence rates of the pathological condition in patients who underwent laser ablation with a Ho:YAG laser for CIN2/3 at our institution from June 2012 to November 2021. We defined the recurrence as histologically confirmed CIN2 or more advanced stage. Age, preoperative diagnosis, human papillomavirus (HPV) genotype, and postoperative high-risk HPV status were recorded to establish their association with recurrence rates. Results: We performed surgery in 607 patients and the 2-year recurrence rate after interventions was 5.6%. Five patients were diagnosed with invasive cancer at the time of recurrence. Older age significantly correlated with higher risk of recurrence, but preoperative CIN grade and preoperative HPV 16/18 status did not significantly affect it. The postoperative high-risk HPV test was 100% sensitive for detecting recurrence. Conclusions: Laser ablation with the Ho:YAG laser yields promising results. Together with postinterventional management, high-risk HPV test after laser ablation should be conducted after diagnostic conization.This study received the approval from the Ethics Committee of the NHO Tokyo Medical Center (Ethics Committee approval number: R22-067).

X-ray beam diagnostics at the MID instrument of the European X-ray Free-Electron Laser Facility.

The Materials Imaging and Dynamics (MID) instrument at the European X-ray Free-Electron Laser Facility (EuXFEL) is equipped with a multipurpose diagnostic end-station (DES) at the end of the instrument. The imager unit in DES is a key tool for aligning the beam to a standard trajectory and for adjusting optical elements such as focusing lenses or the split-and-delay line. Furthermore, the DES features a bent-diamond-crystal spectrometer to disperse the spectrum of the direct beam to a line detector. This enables pulse-resolved characterization of the EuXFEL spectrum to provide X-ray energy calibration, and the spectrometer is particularly useful in commissioning special modes of the accelerator. Together with diamond-based intensity monitors, the imager and spectrometer form the DES unit which also contains a heavy-duty beamstop at the end of the MID instrument. Here, we describe the setup in detail and provide exemplary beam diagnostic results.

Effect of laser corticotomy on canine retraction rate: a split-mouth randomized clinical trial.

BACKGROUND: This study assessed the effect of corticotomy with Er: YAG (erbium-doped yttrium aluminium garnet) laser on the rate of canine retraction. METHODS: This randomized split-mouth controlled clinical trial was conducted on 12 patients undergoing orthodontic treatment with extraction of maxillary first premolars. Following initial leveling and alignment, an alginate impression was made from the maxillary arch, and Er: YAG laser corticotomy was performed in one of the maxillary quadrants of each patient. Canine retraction was started immediately after corticotomy by placement of nickel-titanium (NiTi) closed coil springs at both sides. At the end of each month, alginate records were repeated for 4 months. Study models were scanned, and the anteroposterior movement of canine was quantified bilaterally. Pain was also measured by a visual analog scale (VAS). Probing depth (PPD) of canines and two adjacent teeth was also evaluated and pulp vitality was assessed by performing the cold test. Data were analyzed by paired and independent t-test and one-way ANOVA (alpha = 0.05). RESULTS: The rate of canine retraction was significantly greater in the laser-assisted corticotomy quadrant than the control (P < 0.05). No significant difference existed in posterior anchorage loss, canine rotation angle, PPD, pulp vitality, or pain score between two groups (P > 0.05). CONCLUSIONS: Flapless Er: YAG laser corticotomy significantly enhanced canine retraction rate with no adverse effect on other parameters.

Spontaneous resolution of eruptive papules following ablative laser resurfacing-Case report and review of laser-associated eruptive keratoacanthomas.

BACKGROUND: Keratoacanthomas (KAs) following laser treatment are a rare, but well-described entity. AIM: Herein, we describe a case of eruptive keratoacanthoma (KA) following laser resurfacing treatment and aim to better characterize laser-associated KAs. METHODS: A literature search was performed on PubMed reviewing laser-associated KAs including various characteristics: epidemiology, history of skin cancer, location, and number, type of laser, as well as the management and outcome. RESULTS: Fractional ablative was the most common type of laser triggering KAs, and most cases presented within the first month following treatment. The majority of cases of laser-induced KA had a prior history of a malignant or premalignant skin neoplasm. Laser-induced KAs were treated using modalities similar to KAs arising in other contexts. CONCLUSION: Clinicians need to be knowledgeable and prepared to understand, and manage complications following laser treatments, as rare as they may be, including KAs.

Resurfacing of atrophic facial acne scars with a multimodality CO2 and 1570 nm laser system.

BACKGROUND: Scarring is one of the most prevalent long-term complications of acne vulgaris and has cosmetic, psychological, and social burdens. Contemporary management programs integrate multiple modalities to best address the multiple factors underlying their development and persistence. This work assessed the impact of sequential multimodal laser therapy on acne scar geometrics and texture. METHODS: Adult patients (n = 16) with Fitzpatrick skin type II-IV and presenting with facial acne scars, underwent three combination ablative (CO2), and nonablative (1570 nm) laser treatment sessions at two-month intervals. Treatment was delivered using a ProScan Hybrid applicator, with each regimen including illumination with both ablative and a nonablative lasers applied in a grid mode sequence. Scar microtopography was assessed at baseline and 6 months after the last treatment session. RESULTS: At baseline, all patients had both box and rolling scars, while only three had icepick scars. Six months following treatment, mean scar volume improved from 5.7 ± 5.2 mm3 at baseline to 3.1 ± 3.0 mm3 and mean affected area improved from 165.6 ± 134.0 mm2 94.0 ± 80.1 mm2, translating to 47.0 ± 7.9% and 43.2 ± 8.6% reductions from baseline, respectively. Patients were highly satisfied with treatment outcomes, and no serious adverse reactions were documented during the course of treatment or follow-up. CONCLUSION: Multimodal CO2 and 1570-nm laser treatment improved the surface profilometry of patients with atrophic facial acne scars. Customization of both treatment intervals and laser settings to cosmetic regions, scar profiles and skin phototypes may further enhance treatment outcomes and expand its applicability to additional skin deformities.

Incidence and analysis of intraoperative complications in femtosecond laser-assisted cataract surgery: a large-scale cohort study to establish the learning curve.

AIMS: To assess the safety of femtosecond laser-assisted cataract surgery (FLACS) based on surgical parameters and intraoperative complications analysis and to determine the length of the learning curve for FLACS. METHODS: A prospective consecutive cohort study was conducted on Chinese patients who underwent either FLACS (3289 cases) or contemporaneous conventional phacoemulsification cataract surgery (2130 cases). The laser group was divided into four subgroups in chronological order. We recorded intraoperative complication incidences and compared with surgical parameters between groups. Subgroup analysis was conducted to explore the learning curve of FLACS. RESULTS: The laser group had a 4.93% incidence of incomplete capsulotomies and a 1.22% incidence of anterior capsule tears. Subgroup analysis showed significant differences in 8 aspects between the first 250 cases (50 cases per surgeon) and the last 2539 cases, but only 2 aspects differed between the second 250 cases (50 cases per surgeon) and the last 2539 cases. There were no significant differences between the third 250 cases (50 cases per surgeon) and the last 2539 cases. CONCLUSIONS: The intraoperative complications of FLACS were reported, and the learning curve is associated with a significant reduction in the incidence of intraoperative complications. The length of the basic learning curve of FLACS is 100 cases, and the length of the advanced learning curve was 150 cases. This study demonstrated that FLACS is characterised by a relatively straightforward and secure operative technique.

Combining platelet rich plasma with ablative laser for post acne scars: A review.

Background Acne scars are one of the most common sequelae of inflammatory acne. It commonly affects adolescents and young adults and hence is associated with significant psychological morbidity. It is historically resistant to oral as well as surgical modalities. In the last two decades, ablative lasers (fractional or otherwise) have proven to be effective in management of acne scars. Some studies have proven the efficacy of platelet rich plasma in reducing the adverse effects and improving the efficacy of lasers. Objective Review of the studies combining platelet rich plasma with ablative laser for post acne scars. Methods A literature review of the MEDLINE database for studies evaluating the combination of ablative lasers with platelet rich plasma was performed. Only studies with higher levels of evidence (randomised controlled trials and comparative studies) were included in this review. Results Adding intradermal platelet rich plasma to fractional ablative lasers in the management of post acne scars increases clinical efficacy, reduces downtime as well as frequency and duration of ablative lasers related adverse effects. The efficacy of topical platelet rich plasma is less as compared to intradermal platelet rich plasma. Limitations The studies analysed are heterogeneous in nature with varied protocols and duration of follow up. Conclusions It is recommended to combine the ablative lasers with intradermal platelet rich plasma for better clinical response and reduce adverse effects as well as downtime.

Femtosecond laser-assisted astigmatic keratotomy versus toric IOL implantation for correcting astigmatism in cataract patients: a systematic review and meta-analysis with trial sequential analysis.

AIMS: To compare the refractive and visual outcomes of femtosecond laser-assisted astigmatic keratotomy (FSAK) and toric intraocular lens (IOL) implantation for correcting astigmatism in cataract patients. METHODS: Studies were retrieved from the Ovid-Medline, EMBASE, Cochrane Central Register of Controlled Trials and Scopus which compared FSAK and toric IOL for astigmatism correction in cataract patients. Outcome measures included postoperative refractive cylinder, correction index, uncorrected distance visual acuity (UDVA), the proportion of patients achieving a residual refractive cylinder of 1.00 dioptre or less, target-induced astigmatism (TIA) and surgically induced astigmatism (SIA). The trial sequential analysis (TSA) was used to collect firm evidence supporting our conclusion. RESULTS: 9 studies encompassing 590 participants were analysed. The meta-analysis revealed that toric IOLs could result in less postoperative refractive cylinder and provide better UDVA compared with FSAK. The TSA disclosed strong evidence of lower postoperative refractive cylinder in the toric IOL group compared with that of the FSAK group. FSAK showed a smaller correction index and lower mean TIA and SIA compared with toric IOLs. CONCLUSIONS: For cataract patients, both FSAK and toric IOLs are effective methods for correcting astigmatism. However, toric IOLs offer less postoperative astigmatism and result in better postoperative UDVA compared with FSAK. In vector analysis of astigmatism, toric IOLs can also produce higher TIA and SIA. Additionally, neither method is associated with severe untreatable complications. Therefore, the conclusion is that toric IOLs are the preferred choice for astigmatism correction in cataract patients and FSAK serves as a viable alternative when toric IOLs are contraindicated.

Dirac Cones and Room Temperature Polariton Lasing Evidenced in an Organic Honeycomb Lattice.

Artificial 1D and 2D lattices have emerged as a powerful platform for the emulation of lattice Hamiltonians, the fundamental study of collective many-body effects, and phenomena arising from non-trivial topology. Exciton-polaritons, bosonic part-light and part-matter quasiparticles, combine pronounced nonlinearities with the possibility of on-chip implementation. In this context, organic semiconductors embedded in microcavities have proven to be versatile candidates to study nonlinear many-body physics and bosonic condensation, and in contrast to most inorganic systems, they allow the use at ambient conditions since they host ultra-stable Frenkel excitons. A well-controlled, high-quality optical lattice is implemented that accommodates light-matter quasiparticles. The realized polariton graphene presents with excellent cavity quality factors, showing distinct signatures of Dirac cone and flatband dispersions as well as polariton lasing at room temperature. This is realized by filling coupled dielectric microcavities with the fluorescent protein mCherry. The emergence of a coherent polariton condensate at ambient conditions are demonstrated, taking advantage of coupling conditions as precise and controllable as in state-of-the-art inorganic semiconductor-based systems, without the limitations of e.g. lattice matching in epitaxial growth. This progress allows straightforward extension to more complex systems, such as the study of topological phenomena in 2D lattices including topological lasers and non-Hermitian optics.

The Pixel Anomaly Detection Tool: a user-friendly GUI for classifying detector frames using machine-learning approaches.

Data collection at X-ray free electron lasers has particular experimental challenges, such as continuous sample delivery or the use of novel ultrafast high-dynamic-range gain-switching X-ray detectors. This can result in a multitude of data artefacts, which can be detrimental to accurately determining structure-factor amplitudes for serial crystallography or single-particle imaging experiments. Here, a new data-classification tool is reported that offers a variety of machine-learning algorithms to sort data trained either on manual data sorting by the user or by profile fitting the intensity distribution on the detector based on the experiment. This is integrated into an easy-to-use graphical user interface, specifically designed to support the detectors, file formats and software available at most X-ray free electron laser facilities. The highly modular design makes the tool easily expandable to comply with other X-ray sources and detectors, and the supervised learning approach enables even the novice user to sort data containing unwanted artefacts or perform routine data-analysis tasks such as hit finding during an experiment, without needing to write code.