Revisiting the NIR-to-Visible Upconversion Mechanism in β-NaYF4:Yb(3+),Er(3.)

Here, we show that the long-accepted mechanism for the production of red and blue emission through upconversion (UC) of 1 μm excitation in Yb(3+)/Er(3+)-doped materials does not apply in the popular β-NaYF4 host. We propose a new mechanism involving Yb(3+)-to-Er(3+) energy-transfer UC out of the green-emitting (2)H11/2,(4)S3/2 states that quantitatively accounts for all of the observed optical behavior. Rate constants for the relevant radiative and nonradiative processes are reported along with a prediction of the power dependence of the pulsed and continuous-wave UC quantum efficiency.

Acne scarring: A review of available therapeutic lasers

BACKGROUND AND OBJECTIVE

The utilization of lasers in dermatology has greatly expanded in recent decades. Acne scarring is a common indication in which lasers play an important therapeutic role.

STUDY DESIGN/MATERIALS AND METHODS

Available lasers include traditional ablative lasers, such as carbon dioxide and erbium lasers, traditional non-ablative lasers, such as neodymium, diode, alexandrite, pulsed dye lasers and intense pulse light, as well as both ablative, and non-ablative fractional laser systems.

CONCLUSION

We sought to provide a framework for understanding the various types of lasers available to treat acne scars and review the primary literature pertaining to the efficacy, safety, and advantages of each laser discussed.

Room-Temperature Upconversion in a Nanosized {Ln15} Molecular Cluster-Aggregate

The successive absorption of low-energy photons to the accumulation of the intermediate excited states leading to higher energy emission is still a challenge in molecular architectures. Contrary to low-phonon solids and nanoparticles, the rational construction of molecular systems containing an excess of donor atoms in relation to acceptor ones is far from trivial. Moreover, the vibrations caused by high-energy oscillators commonly present on coordination compounds result in serious drawbacks on molecular upconversion. To overcome these limitations, we demonstrate that upconversion can be achieved even at room temperatures through the use of molecular cluster-aggregates (MCAs). To achieve the upconverted emission, we synthesized a MCA containing 15 lanthanide ions, {Er₂Yb₁₃}, ensuring an excess of donor atoms. With the excitation on the ytterbium ion, the characteristic green and red emissions from erbium were obtained at room temperature. To prove the mechanism behind the upconversion process, four other compositions were synthesized and studied, namely, {Y₁₃Er₂}, {Y₁₀Er₅}, {Er₁₀Yb₅}, and {Y₁₀Er₁Yb₄}. Upconversion quantum yield values on the order of 10^-3% were obtained, values 100000 times higher than for previously reported lanthanide-based molecular upconverting systems. The presented methodology is an interesting approach to address a fine composition control and harness the upconversion properties of nanoscale molecular materials.

Physical methods for the treatment of genitourinary syndrome of menopause: A systematic review

BACKGROUND

Genitourinary syndrome of menopause (GSM) negatively affects sexual function and quality of life. Techniques like laser and radiofrequency are being used to manage GSM, particularly in women with contraindications for hormone therapy.

OBJECTIVES

To verify whether the physical methods of laser and radiofrequency can be recommended as safe and effective options for the treatment of GSM/urinary urgency or incontinence in pre- and postmenopausal women.

SEARCH STRATEGY

Databases were comprehensively searched using combinations of the following keywords in any language: "postmenopause"; "genitourinary syndrome of menopause"; "vaginal atrophy"; "radiofrequency"; and "laser."

SELECTION CRITERIA

Full articles of case-control, cross-sectional, cohort, randomized clinical trials, and quasi-randomized or controlled clinical trials were included.

DATA COLLECTION AND ANALYSIS

All authors independently evaluated the design of the studies for quality of reporting, risk of bias, and quality of evidence.

MAIN RESULTS

Of the included 49 studies, 37 were on the CO₂ laser, 10 on the Erbium laser, and two on radiofrequency.

CONCLUSIONS

Laser and radiofrequency therapy could be promising and safe therapeutic options for GSM/urinary incontinence. However, the study findings cannot be generalized until new randomized clinical trials are performed that confirm the strength of the evidence. This review has been registered with PROSPERO: CRD42020141913.

Current status of surgery in dermatology

An article titled "Current issues in dermatologic office-based surgery" was published in the JAAD in October 1999 (volume 41, issue 4, pp. 624-634). The article was developed by the Joint American Academy of Dermatology/American Society for Dermatologic Surgery Liaison Committee. A number of subjects were addressed in the article including surgical training program requirements for dermatology residents and selected advances in dermatologic surgery that had been pioneered by dermatologists. The article concluded with sections on credentialing, privileging, and accreditation of office-based surgical facilities. Much has changed since 1999, including more stringent requirements for surgical training during dermatology residency, and the establishment of 57 accredited Procedural Dermatology Fellowship Training Programs. All of these changes have been overseen and approved by the Residency Review Committee for Dermatology and the Accreditation Committee for Graduate Medical Education. The fertile academic environment of academic training programs with interaction between established dermatologic surgeons and fellows, as well as the inquisitive nature of many of our colleagues, has led to the numerous major advances in dermatologic surgery, which are described herein.

Influence of Upconversion Processes in the Optically-Induced Inhomogeneous Thermal Behavior of Erbium-Doped Lanthanum Oxysulfide Powders

The efficient infrared-to-visible upconversion emission present in Er-doped lanthanum oxysulfide crystal powders is used as a fine thermal sensor to determine the influence of upconversion processes on the laser-induced thermal load produced by the pump laser and to assess the potentialities of this material in order to obtain anti-Stokes laser-induced cooling. The analysis of the upconversion emission and excitation spectra as well as the decay curves indicates that energy transfer upconversion is the main mechanism responsible for the green (⁴S_3/2) and red (⁴F_9/2) upconversion luminescence. The dependence on temperature of the intensity ratio of upconversion emission from thermally-coupled ²H_11/2 and ⁴S_3/2 levels of Er³⁺ in the 240–300 K temperature range has been used to estimate a relative sensitivity of 1.09 × 10⁻² K⁻¹. Thermal measurements performed on the powder samples by using a thermal infrared camera exhibit a very inhomogeneous heat distribution at the sample surface due to the random distribution of the pumping energy inside the sample as well as to the random properties of the thermal field. The analysis of both spectroscopic and thermal measurements show that after a transient heating induced by the background absorption, cooling of discrete regions by means of anti-Stokes processes can be observed.

Comparison of shear bond strength of composite resin to enamel surface with laser etching versus acid etching: An in vitro evaluation

Introduction:

The aim of the study is in vitro evaluation of the shear bond strength of composite resin bonded to enamel which is pretreated using acid etchant and Er,Cr:Ysgg.

Materials and Methods:

40 extracted human teeth were divided in two groups of 20 each (Groups A and B). In Group A, prepared surface of enamel was etched using 37% phosphoric acid (Scotchbond, 3M). In Group B, enamel was surface treated by a an Er, Cr: YSGG laser system (Waterlase MD, Biolase Technology Inc., San Clemente, CA, USA) operating at a wavelength of 2,780 nm and having a pulse duration of 140-200 microsecond with a repetition rate of 20 Hz and 40 Hz. Bonding agent ((Scotchbond Multipurpose, 3M) was applied over the test areas on 20 samples of Groups A and B each, and light cured. Composite resin (Ceram X duo Nanoceramic restorative, Densply) was applied onto the test areas as a 3 × 3 mm diameter bid, and light cured. The samples were tested for shear bond strength.

Results:

Mean shear bond strength for acid-etched enamel (26.41 ± 0.66MPa, range 25.155 to 27.150 MPa) was significantly higher (P < 0.01) than for laser-etched enamel (16.23 ± 0.71MPa, range 15.233 to 17.334 MPa).

Conclusions:

For enamel surface, mean shear bond strength of bonded composite obtained after laser etching were significantly lower than those obtained after acid etching.

Effect of erbium, chromium: yttrium, scandium, gallium, garnet laser and casein phosphopeptide-amorphous calcium phosphate on surface micro-hardness of primary tooth enamel

Objective:

The aim was to evaluate the effect of Er, Cr: YSGG laser and casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) on surface micro-hardness of primary tooth enamel.

Materials and Methods:

A total of 30 freshly extracted caries free primary anterior teeth were cleaned and stored in 1% thymol. Teeth were embedded in acrylic resin such that only their buccal surfaces were exposed and were divided into four groups. Group I: Five intact teeth (negative control). The remaining 25 teeth were immersed for 30 min in 1% citric acid for demineralization. Group II: Five demineralized teeth (positive control), Group III: CPP-ACP (GC tooth mousse-GC International, Itabashi-Ku, Tokyo, Japan) application and Group IV: Etching using Er, Cr: YSGG laser + CPP-ACP application. Groups III and IV were subjected to pH cycling for 5 days. Surface micro-hardness of all the teeth was measured using Brinell hardness tester (Fuel Instruments and Engineers Pvt. Ltd.). Data were analyzed using ANOVA.

Results:

Mean surface micro-hardness of Groups I and II were 177.43 kgf/mm² and 164.86 kgf/mm², respectively. Group IV showed a higher mean surface micro-hardness (230.68 kgf/mm²) compared with that of Group III (190.28 kgf/mm²). In comparison to all other groups, laser etching prior to CPP-ACP application increased surface micro-hardness significantly (P < 0.001).

Conclusion:

Laser irradiation of primary teeth followed by CPP-ACP application increased surface micro-hardness of enamel.

Visible-Range Sensitization of Er(3+)-Based Infrared Emission from Perfluorinated 2-Acylphenoxide Complexes

Five new fully fluorinated acylphenoxide ligands, which are aromatic analogues of β-diketonates, provide visible photosensitization of the Er(3+4)I13/2 → (4)I15/2 emission at ∼1540 nm (of interest for telecommunications) via the "antenna effect", as observed in Cs[ErL4] compounds. Depending on the chemical functionalization, the excitation wavelength can be tuned in the 400-650 nm range. Decay times for the solids are in the range of 7-16 μs, proving that the complexes can be of interest for a number of optoelectronic and photonic applications.

Narrow Optical Line Widths in Erbium Implanted in TiO2

Atomic and atomlike defects in the solid state are widely explored for quantum computers, networks, and sensors. Rare earth ions are an attractive class of atomic defects that feature narrow spin and optical transitions that are isolated from the host crystal, allowing incorporation into a wide range of materials. However, the realization of long electronic spin coherence times is hampered by magnetic noise from abundant nuclear spins in the most widely studied host crystals. Here, we demonstrate that Er³⁺ ions can be introduced via ion implantation into TiO₂, a host crystal that has not been studied extensively for rare earth ions and has a low natural abundance of nuclear spins. We observe efficient incorporation of the implanted Er³⁺ into the Ti⁴⁺ site (>50% yield) and measure narrow inhomogeneous spin and optical line widths (20 and 460 MHz, respectively) that are comparable to bulk-doped crystalline hosts for Er³⁺. This work demonstrates that ion implantation is a viable path to studying rare earth ions in new hosts and is a significant step toward realizing individually addressed rare earth ions with long spin coherence times for quantum technologies.

Room Temperature Resonant Photocurrent in an Erbium Low-Doped Silicon Transistor at Telecom Wavelength

An erbium-doped silicon transistor prepared by ion implantation and co-doped with oxygen is investigated by photocurrent generation in the telecommunication range. The photocurrent is explored at room temperature as a function of the wavelength by using a supercontinuum laser source working in the μW range. The 1-μm² transistor is tuned to involve in the transport only those electrons lying in the Er-O states. The spectrally resolved photocurrent is characterized by the typical absorption line of erbium and the linear dependence of the signal over the impinging power demonstrates that the Er-doped transistor is operating far from saturation. The relatively small number of estimated photoexcited atoms (≈ 4 × 10 4 ) makes Er-dpoed silicon potentially suitable for designing resonance-based frequency selective single photon detectors at 1550 nm.

Comparative evaluation of surface topography of tooth prepared using erbium, chromium: Yttrium, scandium, gallium, garnet laser and bur and its clinical implications

Background:

Erbium, chromium: Yttrium, scandium, gallium, garnet (Er, Cr: YSGG) laser has been successfully used in the ablation of dental hard and soft tissues. It has been reported that this system is also useful for preparing tooth surfaces and etching, but no consensus exist in the literature regarding the advantage of lasers over conventional tooth preparation technique.

Materials and Methods:

Labial surfaces of 25 extracted human maxillary central incisors were divided into two halves. Right half was prepared with diamond bur and left half with Er, Cr; YSGG laser and a reduction of 0.3–0.5 mm was carried out. Topography of prepared surfaces of five teeth were examined under scanning electron microscope (SEM). The remaining samples were divided into 4 groups of 10 specimens each based on the surface treatment received: One group was acid etched and other was nonetched. Composite resin cylinders were bonded on prepared surfaces and shear bond strength was assessed using a universal testing machine.

Results:

The SEM observation revealed that the laser prepared surfaces were clean, highly irregular and devoid of a smear layer. Bur prepared surfaces were relatively smooth but covered with smear layer.

Highest bond strength was shown by laser prepared acid etched group, followed by bur prepared the acid etched group. The bur prepared nonacid etched group showed least bond strength.

Conclusions:

Er, Cr: YSGG laser can be used for preparing tooth and bond strength value achieved by laser preparation alone without surface treatment procedure lies in the range of clinical acceptability.

Solvato Modulation of the Magnetic Memory in Isotopically Enriched Erbium Polyoxometalate

Single-Molecule Magnet (SMM) property is by essence molecular, while commonly measured in solid crystalline state. Solvent crystallization molecules are usually neglected in the analysis and interpretation of solid-state properties. The solvation/desolvation process in the polyoxometalate(POM)-based Na₉ [Er(W₅ O₁₈ )₂ ] ⋅ 35 H₂ O SMM demonstrates that the dehydrated form relaxes more than 1000 times faster than the initial state, while the rehydration process allows the quasi complete recovering of the initial magnetic behaviour. This dehydration process is monitored by thermogravimetric analysis (TGA) and temperature-dependent X-ray powder diffraction, and rationalized by periodic quantum chemical calculations evidencing the tremendous role of the labile water molecules in the stability of the edifice. Ab-initio calculations highlight that sodium ions localization in the structure drive the magnetic responses. Isotopic enrichment with nuclear spin free (¹⁶⁶ Er, I=0) Er^III ions shows that the relaxation dynamics in the quantum regime depends on the nuclear spin.

Nanoscale evidence of erbium clustering in Er-doped silicon-rich silica

: Photoluminescence spectroscopy and atom probe tomography were used to explore the optical activity and microstructure of Er3+-doped Si-rich SiO2 thin films fabricated by radio-frequency magnetron sputtering. The effect of post-fabrication annealing treatment on the properties of the films was investigated. The evolution of the nanoscale structure upon an annealing treatment was found to control the interrelation between the radiative recombination of the carriers via Si clusters and via 4f shell transitions in Er3+ ions. The most efficient 1.53-μm Er3+ photoluminescence was observed from the films submitted to low-temperature treatment ranging from 600°C to 900°C. An annealing treatment at 1,100°C, used often to form Si nanocrystallites, favors an intense emission in visible spectral range with the maximum peak at about 740 nm. Along with this, a drastic decrease of 1.53-μm Er3+ photoluminescence emission was detected. The atom probe results demonstrated that the clustering of Er3+ ions upon such high-temperature annealing treatment was the main reason. The diffusion parameters of Si and Er3+ ions as well as a chemical composition of different clusters were also obtained. The films annealed at 1,100°C contain pure spherical Si nanocrystallites, ErSi3O6 clusters, and free Er3+ ions embedded in SiO2 host. The mean size and the density of Si nanocrystallites were found to be 1.3± 0.3 nm and (3.1± 0.2)×1018 Si nanocrystallites·cm-3, respectively. The density of ErSi3O6 clusters was estimated to be (2.0± 0.2)×1018 clusters·cm-3, keeping about 30% of the total Er3+ amount. These Er-rich clusters had a mean radius of about 1.5 nm and demonstrated preferable formation in the vicinity of Si nanocrystallites.

Quasi-BIC Modes in All-Dielectric Slotted Nanoantennas for Enhanced Er3+ Emission

In the quest for new and increasingly efficient photon sources, the engineering of the photonic environment at the subwavelength scale is fundamental for controlling the properties of quantum emitters. A high refractive index particle can be exploited to enhance the optical properties of nearby emitters without decreasing their quantum efficiency, but the relatively modest Q-factors (Q ∼ 5-10) limit the local density of optical states (LDOS) amplification achievable. On the other hand, ultrahigh Q-factors (up to Q ∼ 10⁹) have been reported for quasi-BIC modes in all-dielectric nanostructures. In the present work, we demonstrate that the combination of quasi-BIC modes with high spectral confinement and nanogaps with spacial confinement in silicon slotted nanoantennas lead to a significant boosting of the electromagnetic LDOS in the optically active region of the nanoantenna array. We observe an enhancement of up to 3 orders of magnitude in the photoluminescence intensity and 2 orders of magnitude in the decay rate of the Er³⁺ emission at room temperature and telecom wavelengths. Moreover, the nanoantenna directivity is increased, proving that strong beaming effects can be obtained when the emitted radiation couples to the high Q-factor modes. Finally, via tuning the nanoanntenna aspect ratio, a selective control of the Er³⁺ electric and magnetic radiative transitions can be obtained, keeping the quantum efficiency almost unitary.

Exploration of the Temperature Sensing Ability of La2MgTiO6:Er3+ Double Perovskites Using Thermally Coupled and Uncoupled Energy Levels

This work aimed to explore the temperature-sensing performance of La2MgTiO6:Er3+ double perovskites based on thermally coupled and uncoupled energy levels. Furthermore, the crystal structure, chemical composition, and morphology of the samples were investigated by powder X-ray diffraction, energy-dispersive X-ray spectroscopy, and scanning electron microscopy, respectively. The most intense luminescence was observed for the sample doped with 5% Er3+. The temperature-dependent emission spectra of La2MgTiO6:5% Er3+ were investigated in the wide range of 77-398 K. The highest sensitivity of the sample was equal to 2.98%/K corresponding to the thermally coupled energy level 2H11/2 → 4I15/2 and 4S3/2 → 4I15/2 as compared to 1.9%/K, obtained for the uncoupled energy level 2H11/2 → 4I15/2 and 2H9/2 → 4I15/2. Furthermore, the 300 K luminescent decay profiles were analyzed using the Inokuti-Hirayama model. The energy transfer among Er3+ ions was mainly regulated by the dipole-dipole mechanism. The critical transfer distance R0, critical concentration C0, energy transfer parameter Cda, and energy transfer probability Wda were 9.81 Å, 2.53×1020 ions·cm-3, 5.38×10-39 cm6·s-1, and 6020 s-1, respectively.

Influence of erbium, chromium-doped: Yttrium scandium-gallium-garnet laser etching and traditional etching systems on depth of resin penetration in enamel: A confocal laser scanning electron microscope study

OBJECTIVE

This study was performed to assess the resin tag length penetration in enamel surface after bonding of brackets to identify which system was most efficient.

METHODOLOGY

Our study was based on a more robust confocal microscopy for visualizing the resin tags in enamel. Totally, 100 extracted human first and second premolars have been selected for this study and were randomly divided into ten groups of 10 teeth each. In Group 1, the buccal enamel surface was etched with 37% phosphoric acid (3M ESPE), Group 2 with 37% phosphoric (Ultradent). In Groups 5, 6, and 7, erbium, chromium-doped: Yttrium scandium-gallium-garnet (Er, Cr: YSGG) laser (Biolase) was used for etching the using following specifications: Group 5 (1.5 W/20 Hz, 15 s), Group 6 (2 W/10 Hz, 15 s), and Group 7 (2 W/20 Hz, 15 s). In Groups 8, 9, and 10, Er, Cr: YSGG laser (Biolase) using same specifications and additional to this step, conventional etching on the buccal enamel surface was etched with 37% (3M ESPE) after laser etching. In Groups 1, 5, 6, 7, 8, 9, and 10 3M Unitek Transbond XT primer was mixed with Rhodamine B dye (Sigma-Aldrich, Germany) to etched surface and then cured for 20 s. In Group 2, Ultradents bonding agent was mixed with Rhodamine B. In Group 3, 3M Unitek Transbond PLUS, Monrovia, USA, which was mixed with Rhodamine B dye (Sigma-Aldrich, Germany). Group 4, with self-etching primer (Ultradent-Peak SE, USA) was mixed with Rhodamine B dye (Sigma-Aldrich, Germany). Later (3M Unitek, Transbond XT, Monrovia USA) [Figure 1] was used to bond the modified Begg brackets (T. P. Orthodontics) in Groups 1, 3, 5, 6, 7, 8, 9, and 10. In Groups 2, 4 Ultradent-Peak LC Bond was used to bond the modified brackets. After curing brackets were debonded, and enamel depth penetration was assessed using confocal laser scanning microscope.

RESULTS

Group J had a mean maximum depth of penetration of 100.876 μm, and Group D was the least having a maximum value of 44.254 μm.

CONCLUSIONS

Laser alone groups had comparable depths of penetration to that of self-etching groups but much lower than conventional acid etched groups.

The effect of an erbium, chromium: yttrium-scandium-gallium-garnet laser on the microleakage and bond strength of silorane and micro-hybrid composite restorations

Objective:

The aim of this in vitro study was to compare the microleakage and bond strength of Class V silorane-based and universal micro-hybrid composite restorations prepared either with diamond bur or with an erbium, chromium: yttrium-scandium-gallium-garnet (Er, Cr:YSGG) laser.

Materials and Methods:

A total of 160 molar teeth were used for microleakage assessment and shear bond strength (SBS) test. The specimens were prepared using either diamond bur or 3 W-, 4 W- and 5 W-20 Hz Er, Cr:YSGG laser irradiation. All specimens were subjected to thermocycling (500 times at 5 ± 2°C to 55 ± 2°C, dwell time 15 s and transfer time 10 s). Microleakage was assessed using a 0.5% basic-fuchsin solution. The bond strengths were determined using a microtensile tester at a crosshead speed of 0.5 mm/min. The Kruskal Wallis test was used for the analysis of microleakage and a one-way analysis of variance test was used to analyze the SBS (P < 0.05).

Results:

No statistically significant differences were found (P > 0.05) between Er, Cr:YSGG laser and bur preparation methods regarding microleakage and bond strength values.

Conclusion:

Irradiation with Er, Cr:YSGG laser was confirmed to be as effective as conventional methods for preparing cavities before adhesive restorations.

Er, Cr:YSGG laser for the treatment of ankyloglossia

Ankyloglossia or tongue-tie is the result of a short and tight lingual frenum causing difficulty in speech, feeding problems in infants due to the limitation of tongue movement. This report presents a case of a 22-year-old female with tongue-tie who complained of difficulty in speech following which she underwent frenectomy procedure with erbium, chromium: yattrium-scandium-gallium-garnet laser without any complications. She was referred to the speech therapist after the procedure.

Adhesion in Dentin Prepared with Er,Cr:YSGG Laser: Systematic Review

Background:

In dentistry, cavities prepared with Erbium lasers present more advantages, compared to traditional methods, but there is still a lack of investigation about the adhesion in dentin surfaces prepared with Erbium lasers, especially with Erbium, chromium:yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser.

Aim:

The purpose of this systematic review was to find out which might be “The most adequate adhesive and laser parameters for adhesion in dentin prepared with Er,Cr:YSGG laser.”

Methods:

An electronic search was performed in the PubMed database. The search was limited to studies between 2009 and 2016.

Results:

Ten articles were selected to the systematic review according to TRANSPARENT REPORTING of Systematic Reviews and Meta-ANALYSES checklist.

Conclusions:

The adhesive that showed the best bond strength results in dentin prepared with Er,Cr:YSGG laser was the self-adhesive Clearfil™ SE (Kuraray), with preconditioning with 40% phosphoric acid. The settings 2 W, 75% water, 60% air, 140 μs pulse duration, and 20 Hz showed the best adhesion outcome.

Outcomes and adverse effects of ablative vs nonablative lasers for skin resurfacing: A systematic review of 1093 patients

It is generally believed that ablative laser therapies result in prolonged healing and greater adverse events when compared with nonablative lasers for skin resurfacing. To evaluate the efficacy of ablative laser use for skin resurfacing and adverse events as a consequence of treatment in comparison to other modalities, a PRISMA-compliant systematic review (Systematic Review Registration Number: 204016) of twelve electronic databases was conducted for the terms "ablative laser" and "skin resurfacing" from March 2002 until July 2020. Studies included meta-analyses, randomized control trials, cohort studies, and case reports to facilitate evaluation of the data. All articles were evaluated for bias. The search strategy produced 34 studies. Of 1093 patients included in the studies of interest, adverse events were reported in a total of 106 patients (9.7%). Higher rates of adverse events were described in nonablative therapies (12.2% ± 2.19%, 31 events) when compared with ablative therapy (8.28% ± 2.46%, 81 events). 147 patients (13.4%) reported no side effects, 68 (6.22%) reported expected, transient self-resolving events, and five (0.046%) presented with hypertrophic scarring. Excluding transient events, ablative lasers had fewer complications overall when compared with nonablative lasers (2.56% ± 2.19% vs 7.48% ± 3.29%). This systematic review suggests ablative laser use for skin resurfacing is a safe and effective modality to treat a range of pathologies from photodamage and acne scars to hidradenitis suppurativa and posttraumatic scarring from basal cell carcinoma excision. Further studies are needed, but these results suggest that ablative lasers are a superior, safe, and effective modality to treat damaged skin.

Application of Cyanobacteria Arthospira platensis for Bioremediation of Erbium-Contaminated Wastewater

Erbium belongs to rare earth elements critical for industry, especially nuclear technology. Cyanobacteria Arthospira platensis was used for Er(III) removal from wastewater by applying biosorption and bioaccumulation processes. The influence of pH, Er(III) concentration, contact time and temperature on the biosorption capacity of Arthospira platensis was determined. The optimal conditions for Er(III) removal were defined as pH 3.0, time 15 min and temperature 20 °C, when 30 mg/g of Er(III) were removed. The kinetics of the process was better described by the pseudo-first-order model, while equilibrium fitted to the Freundlich model. In bioaccumulation experiments, the uptake capacity of biomass and Er(III) effect on biomass biochemical composition were assessed. It was shown that Er(III) in concentrations 10-30 mg/L did not affect the content of biomass, proteins, carbohydrate and photosynthetic pigments. Its toxicity was expressed by the reduction of the lipids content and growth of the level of malonic dialdehyde. Biomass accumulated 45-78% of Eu(III) present in the cultivation medium. Therefore, Arthospira platensis can be considered as a safe and efficient bioremediator of erbium contaminated environment.

Erbium Luminescence Centres in Single- and Nano-Crystalline Diamond-Effects of Ion Implantation Fluence and Thermal Annealing

We present a fundamental study of the erbium luminescence centres in single- and nano-crystalline (NCD) diamonds. Both diamond forms were doped with Er using ion implantation with the energy of 190 keV at fluences up to 5 × 1015 ions·cm-2, followed by annealing at controllable temperature in Ar atmosphere or vacuum to enhance the near infrared photoluminescence. The Rutherford Backscattering Spectrometry showed that Er concentration maximum determined for NCD films is slightly shifted to the depth with respect to the Stopping and Range of Ions in Matter simulation. The number of the displaced atoms per depth slightly increased with the fluence, but in fact the maximum reached the fully disordered target even in the lowest ion fluence used. The post-implantation annealing at 800 °C in vacuum had a further beneficial effect on erbium luminescence intensity at around 1.5 μm, especially for the Er-doped NCD films, which contain a higher amount of grain boundaries than single-crystalline diamond.

Efficacy of combining erbium:YAG and fractional CO2 laser for the treatment of facial scarring

Background

Laser intervention is increasingly recognized as an effective approach to preventing scars, however, as lasers of different wavelengths reach different target tissues, an appropriate combination of laser treatment is required.

Objectives

To evaluate the efficacy of combining erbium: yttrium aluminium garnet (Er:YAG) 2,940-nm laser and fractional carbon dioxide (CO2) 10,600-nm laser for the treatment of facial scarring.

Materials & Methods

Medical records of 39 patients with facial scars were retrospectively reviewed. Treatments initiated within six months post-injury were defined as "early-intervention", whereas those initiated >six months post-injury were defined as "delayed-intervention". Patients' scores on the Vancouver Scar Scale (VSS) and Visual Analogue Scale (VAS) were collected and compared between different timepoints using the paired t-test. Improvement in pigmentation, height, vascularity and pliability was analysed between baseline and after final treatment.

Results

Between March 2020 and March 2022, 39 patients underwent dual-laser therapy at our laser clinic. The average number of treatments was 4.69 1.54; 18 patients in the early-intervention and 21 patients in the delayedintervention group. Facial scars significantly improved after the first treatment in the delayed-intervention group (p < 0.001), however, there was no significant improvement until two sessions were completed in the early-intervention group (p < 0.001). In the delayed-intervention group, improvement in vascularity was insignificant (p = 0.083), however, improvement in height and flexibility was prominent (p < 0.001). In the early-intervention group, facial scars improved in all four dimensions of VSS (p < 0.05), with improvement of vascularity being the most significant. Side effects were self-limited, and complications were not noted.

Conclusion

The combination of Er:YAG and fractional CO2 laser is a safe and effective therapeutic modality for facial scarring.

Comparison of clinical efficacy of diode laser and erbium, chromium: Yttrium, scandium, gallium, and garnet for implant stage 2 recovery procedure - A randomized control clinical study

Aim:

The aim is to compare the clinical efficacy of diode laser and erbium, chromium-doped yttrium, scandium, gallium, and garnet (Er, Cr:YSGG) laser for implant stage 2 recovery procedure.

Materials and Methods:

A total of 30 patients who had undergone dental implant placement were included in this study. The subjects were randomly allocated into three groups. Group 1 patients (n = 10) had implant recovery using diode laser, Group 2 (n = 10) implant recovery with Er, Cr:YSGG and conventional scalpel method (n = 10) was the third group. The pain assessment was recorded using visual analog scale (VAS scale), time taken for the procedure, intra-operative bleeding, time taken for healing were recorded for the three groups.

Results:

Data were tabulated and the results were analyzed using SPSS software version 26. Mann–Whitney U-test was used to compare the postoperative analgesic used, postoperative VAS score, the time taken for recovery and time taken for healing between the three study groups. Results were considered to be statistically significant when P < 0.05. Operation duration under Er, Cr:YSGG were much faster than the diode laser, however the results were not statistically significant (P = 0.051). The operation time under Er, Ch: YSGG and laser were faster than the conventional scalpel group (P = 0.000). The time taken for healing was faster in the Er, Cr:YSGG laser group than the diode laser and the scalpel group (P = 0.000). VAS scale at day 0 was higher in the conventional group than the two laser groups (P = 0.000).

Conclusion:

Considering the advantages of both these laser systems such as less anesthesia, less surgical trauma and faster healing, and post-operative comfort, lasers are an effective tool for implant stage two recovery techniques. However, since diode lasers are more cost effective when compared to Er, Cr:YSGG, diode lasers may meet the clinical needs when compared to hard-tissue lasers.