Erbium Laser Research Articles

Combined Treatment of Rolling Acne Scars in Ethnic Skin Using Extensive Subcision, Trichloracetic Acid Peel, and Fractional Ablative Erbium Laser.

BACKGROUNDSuccessful treatment of acne scars in ethnic skin requires procedures that are safe and effective with a low incidence of hyper or hypopigmentation postoperatively.OBJECTIVEIn this study, the safety and efficacy of a combined treatment protocol including tumescent anesthesia, subcision, trichloracetic acid peel, and fractional erbium laser resurfacing was evaluated.METHODSThis is a retrospective study of 56 patients (22 women and 34 men) with predominantly rolling acne scars and Fitzpatrick skin Types IV–VI who were treated using a combination of tumescent anesthesia, extensive subcision, fractional ablative erbium laser, and a blending 20% trichloracetic acid (TCA) peel.RESULTSThe mean improvement after a single treatment, assessed by 3 independent evaluators (2 dermatologist and 1 dermatology physician assistant), was 2.52 (SD = 1.04) on a scale of 1 to 4.CONCLUSIONThe combination of tumescent anesthesia, extensive subcision, fractional ablative erbium laser resurfacing, and a blending 20% TCA peel (combined procedure) is both safe and effective in the treatment of rolling acne scars in ethnic skin types with acceptable temporary adverse effects.

Broadband Metallic Carbon Nanotube Saturable Absorber for Ultrashort Pulse Generation in the 1500–2100 nm Spectral Range

Herein, we report on the possibility of ultrashort laser pulse generation in the broadband spectral range using a saturable absorber based on free-standing metallic carbon nanotube thin film. Erbium, thulium, and holmium-doped all-fiber lasers were mode-locked with a single saturable absorber containing a 300 nm thick material layer. Subpicosecond pulses were generated at 1559, 1938, and 2082 nm. Our work validates the broadband operation of metallic carbon nanotube-based saturable absorbers and highlights the suitable performance of nanomatematerial for ultrafast photonic applications.

Comparative evaluation of the shear bond strength of ceramic brackets of three different base designs bonded to amalgam and composite restorations with different surface treatment.

Nowadays, due to the increasing number of adult orthodontic applicants, who also have multiple dental restorations, it is important to have the ability to bond an orthodontic appliance to restoration surfaces. The aim of this paper was to determine the shear bond strength of ceramic brackets of 3 different base designs bonded to amalgam and composite restorations after using different surface treatment methods in vitro. In an in vitro study, the surfaces of 180 amalgam and composite specimens were prepared by using sandblasting and the erbium, chromium-doped yttrium, scandium, gallium, and garnet (Er,Cr:YSGG) laser irradiation. Ceramic brackets of 3 base designs, including Star, Cross and Slot, for upper central teeth were bonded to amalgam and composite surfaces by using Transbond™ XT Light Cure Adhesive. All specimens were incubated at a temperature of 37°C for 1 week, and then subjected to shear bond strength tests after 1,000 cycles of thermal cycling. The bond strength of the groups was analyzed by means of the one-way and two-way analysis of variance (ANOVA), and the comparison of the 2 groups was made with Tukey's test. Residual adhesives were also determined by a 4-part criterion (0-3) in different groups and the results were analyzed with the χ2 test. There was a significant difference in the shear bond strength of brackets of 3 base designs bonded to amalgam and composite surfaces with different surface treatment. According to the results of this study, all surface treatment methods and different bracket base designs were able to provide sufficient shear bond strength on composite and amalgam surfaces. As far as the bracket base design is concerned, the use of each of the 3 base designs in the amalgam group brought desirable results in terms of the adhesive remnant index (ARI) and shear bond strength values; the use of the Star base design in the composite group proved to be suitable.

Evaluation of the Effectiveness of Erbium Lasers on Removing Calcium Hydroxide

Objective: The purpose of this study was to compare the efficacy of Erbium, chromium-doped yttrium, scandium, gallium and garnet (Er,Cr:YSGG), and Erbium-doped yttrium aluminum garnet laser (Er:YAG) lasers with passive ultrasonic irrigation (PUI) and conventional syringe irrigation (CSI) for the removal of calcium hydroxide [Ca(OH)2] paste from standardized canal irregularities. Methods: Forty single-rooted human teeth were split longitudinally, forming halves, and cut a standardized groove in canal walls. After filling each groove with Ca(OH)2 paste, the teeth were reassembled and stored for 1 week. Ca(OH)2 was removed with CSI by using 10 milliliters (mL) of 5% sodium hypochlorite (NaClO) and 10 mL of 17% ethylenediaminetetraacetic acid (EDTA), respectively. The teeth were randomly divided into four groups (n=10). CSI group was irrigated with10 mL of 5% NaClO, 10 mL of 17% EDTA, and 10 mL of distilled water with CSI (control group), respectively. In Er:YAG group, 5% NaClO was activated with Er:YAG laser, and in Er,Cr:YSGG group, Er,Cr:YSGG laser equipped with Radial Firing Tip 2 (RFT 2) was used. In the PUI group, PUI was used with 2.5% NaClO. All groups received irrigation with 10 mL of distilled water as final irrigation. The root halves were examined with a stereomicroscope using a 4-grade scoring system. Results: Residues of Ca(OH)2 in artificial grooves were observed in all groups. In Er,Cr:YSGG group, only three specimens got a score of 1 (less than half of the groove is filled). Er,Cr:YSGG group was found slightly higher yet the difference was found to be not significant with other groups. Conclusions: Although Er,Cr:YSGG laser equipped with RFT 2 tip seems to have a superior effect on removing Ca(OH)2 from the standardized canal irregularities, there was no statistically significant difference between the applications.

Effects of erbium laser radiation on the dentin organic matrix

The aim of this study was to conduct a review of the literature about the effects of Er:YAG and Er,Cr:YSGG lasers on the dentin organic matrix, and its effect on dentin adhesion. An electronic search was performed on PubMed, SciELO, and Cochrane Library databases. The search was limited to studies from 2000 to 2020. According to the literature, the use of water irrigation is crucial to avoid uncontrolled increase of the dentin temperature. Long pulse durations showed worst results, because energy is transformed into conductive heat, leading to significant alterations of the dentin organic components. Output energy and frequency used, also influenced the dentin characteristics, and a good management of these two parameters is needed to not provoke greater damage on the dentin organic matrix. The effects of erbium laser irradiation on the dentin organic matrix depend on the parameters used, and, consequently, affect the adhesion to dentin. The lack of studies and the heterogeneity between the selected ones were limitations of this review.

The effectiveness of the combined use of RF therapy and laser technology in the correction of involutive changes in the skin of the face

Bipolar radio-frequency devices have all the theoretical prerequisites for use in combination with phototechnologies, while the properties of electro-optical synergy are manifested.
 Material and method. The study included 125 patients aged 40 to 50 years. Depending on the therapy, patients were divided into 4 groups and subgroups A and B, depending on the identified predictors of the effectiveness of laser therapy.
 The results of the study. After applying the combined methods, a more significant improvement in the quality characteristics of the skin was noted: an increase in skin moisture in the 1A group, the corneometry index increased by 24.6%, in the 1st group by 28.3%, in the 2A group by 38.9%, in the 2B group by 37.3%, in the 3A group by 29.1%, in the 3B group by 27.5%, in the 4A group by 38.8%, in the 4B group by 38.8%; an increase in skin elasticity in group 1A, the Ua/Uf indicator increased by 13.2%, in group 1B by 13.9%, in group 2A by 27.9%, in group 2B by 29.0%, in group 3A by 14.9%, in the 3B group by 14.6%, in the 4A group by 28.2%, in the 4B group by 28.2%, which was accompanied by a more pronounced decrease in the severity of wrinkles according to profilometry. The use of laser therapy (an erbium or neodymium laser) and microneedle RF therapy contributes to a more significant restoration of the epidermal-dermal structure of the skin, which is confirmed by ultrasound data: the microrelief has improved by more than 3 times compared with monotherapy, the thickness of the dermis is 2.2 times and acoustic density 1.7 times.
 Conclusions. Combined methods, to a greater extent than mono-laser therapy, contribute to improving the quality of life of patients according to the dynamics of the LHC index, which decreased in groups 1 and 3 by an average of 47.1% and 44.4% versus 57.8% and 64.3% in 2 and 4 groups, while there was a significant difference in the values of the index of HSCI in groups A and B (p 0.01). In accordance with the VAS and GAIS indicators, the optimal effect after a course of therapy with preservation of the results after 1 year was achieved in 25/12.5% of patients in group 1A, in 46.7/33.3% in group 1B, 7/37.5% of patients of group 2A, 78.6/71.4% of patients of group 2B, 33.3/20.0% of patients of group 3A, 50.0/25% of patients 3B groups, 58.8/58.8% and 75.0/75.0% in patients 4A and 4B of the group, respectively, which indicates the high efficiency of the combined methods and the persistence of the results.

The effect of post-extraction socket preservation laser treatment on bone density 4 months after extraction: Randomized controlled trial.

BackgroundPost‐extraction bone resorption may affect the outcome of ensuing restorations.PurposeThis study aimed to evaluate a comprehensive laser post‐extraction protocol by comparing resulting alveolar bone regeneration with that obtained after standard extraction procedure.Materials and MethodsAbout 53 simple extractions were randomized to either laser or control group. In the laser group, erbium (Er:YAG; 2940 nm) and neodymium (Nd:YAG; 1064 nm) lasers were used for degranulation, disinfection, de‐epithelialization of the surrounding gingiva, clot stabilization, and photobiomodulation. The primary outcome measure was change in bone density in the extraction area between day 1 and 4 months after extraction. Patients were monitored for potential side effects.ResultsIncrease in bone density at the follow‐up CBCT was significantly higher in laser than in control group (p < 0.001). No post‐operative pain, bleeding, or swelling was present in the laser group. In the control group, one patient had bleeding 3–5 days after extraction, two patients had swelling and three patients reported post‐operative pain rated 3–5 on a 0–10 pain scale up to 3 days after extraction.ConclusionsThe proposed laser post‐extraction procedure is a safe and effective method to improve post‐extraction bone healing.

Efficacy of different irrigation technique in simulated curved root canals.

The aim of this study was to assess the influence of the canal curvature on the efficacy of sonically, ultrasonically, and laser-activated irrigation in removing a biofilm-mimicking hydrogel (BMH) from simulated canal irregularities. Transparent resin blocks containing a curved root canal (40° or 60°) were used as test models. A 4-mm groove at 1 mm from the apex was filled with BMH. Five different irrigation procedures were performed (n=20): needle irrigation (NI), EndoActivator (EA), Eddy, ultrasonically activated irrigation (UAI) (Irrisafe), and laser-activated irrigation (LAI) using a pulsed erbium laser (PIPS approach). All protocols were executed for 3×20s. Images of the groove were taken before and after irrigation, and the percentage BMH removal was calculated using image analysis software. In the 40° canal curvature model, the highest BMH removal was observed for UAI (99.9%), yielding a significantly better removal than that of EA (57.2%) and NI (53.8%), but not of LAI (96.8%) and Eddy (99.4%). In the 60° canal curvature model, UAI removed 99.5%, which resulted in significantly greater hydrogel removal than all other groups (P < 0.05). The difference between LAI (82.5%) and Eddy (78.1%) was not statistically significant, but both were more effective than EA (13.5%) and NI (7.3%). Canal curvature negatively affects the cleaning efficacy of different irrigation methods. The effect was most pronounced for the sonic techniques, while this was not the case for UAI. This could be ascribed to the prebent ultrasonic tip. Despite the position of the laser tip at the orifice level, fluid streaming during LAI resulted in substantial BMH removal beyond the curve.

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

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. 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. Databases were comprehensively searched using combinations of the following keywords in any language: "postmenopause"; "genitourinary syndrome of menopause"; "vaginal atrophy"; "radiofrequency"; and "laser." Full articles of case-control, cross-sectional, cohort, randomized clinical trials, and quasi-randomized or controlled clinical trials were included. All authors independently evaluated the design of the studies for quality of reporting, risk of bias, and quality of evidence. Of the included 49 studies, 37 were on the CO2 laser, 10 on the Erbium laser, and two on radiofrequency. 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.

Influence of Low-Level Laser Modification and Adhesive Application Mode on the Bonding Efficiency of Universal Adhesives to Er:YAG Laser-Ablated Dentin.

Introduction: Erbium laser ablation as a method of tooth preparation and conditioning has shown promising results. Although previous studies have adopted various combinations of different laser parameters and several dentin adhesive systems, very few have investigated combining high-level and low-level ER:YAG lasers with Universal adhesives. This study aimed to assess the impact of using low-energy irradiation on the surface micro-topography and shear bond strength (SBS) of universal adhesive (UA) to the erbium:yttrium-aluminum-garnet (Er:YAG) laser-ablated dentin substrate, bonded in etch-and-rinse or self-etch adhesive mode. Methods: Eighty-seven extracted molars were sectioned to expose flat occlusal dentin surface; 60 teeth were divided equally into three groups according to the surface treatment; bur-cutting (B), Er:YAG high-energy laser cutting (L1 - 200 mJ, 20 Hz, 50 μs pulse), or L1 followed by low-energy laser modification (L1 /L2 - 80 mJ, 10 Hz, 50 μs pulse). Then each group was equally divided into two groups (n=10) according to the mode of application of the universal adhesive; either etch-and-rinse (ER) or self-etching (SE). The samples were subjected to thermocycling (5000 cycle between 5°C and 55°C), and SBS was tested. Two-way ANOVA and Tukey post hoc test were used to analyze the results. The remaining 27 samples were used to investigate the effect of the treatment on the topography of the treated dentin surfaces using a scanning electron microscope (SEM). Results: B/SE recorded the highest SBS (25.48 ± 2.6 MPa) followed by B/ER (23.20 ± 6.8 MPa) and L1 /L2 /SE (22.94 ± 4.1 MPa) and with no statistically significant difference between these groups (P >0.05). The lowest SBS results (P <0.05) were recorded for L1/SE (12.22 ± 3 MPa). No statistical differences were found between the SBS of L1 /L2 /ER and L1 /ER groups or between the SBS of L1 /L2 / ER and L1 /L2 /SE groups. Conclusion: A subsequent treatment of the Er:YAG laser-ablated dentin with low-energy laser modification mode (LMM) enhances the SBS of the tested UA when applied in SE mode.

Linear and non-linear optical properties of transparent glass-ceramics based on Co2+-doped Zn(Al,Ga)2O4 spinel nanocrystals

Transparent glass-ceramics containing Co2+:Zn(Al,Ga)2O4 spinel nanocrystals with sizes of 6-11 nm were prepared on the basis of the glass of the ZnO-Al2O3-Ga2O3-SiO2 system nucleated by TiO2. The absorption and luminescence properties of these glass-ceramics are defined mainly by tetrahedrally coordinated Co2+ ions located in Zn(Al,Ga)2O4 nanocrystals with spinel structure. Co2+ ions in glass-ceramics exhibit absorption saturation at 1.54 µm (the 4A2(4F)→4T1(4F) transition of Co2+ ions in tetrahedrally coordinated sites). This absorption band is shifted to higher wavelengths by 20 nm as compared with glass-ceramics with no Ga2O3 addition. The concentration of Co2+ ions in Zn(Al,Ga)2O4 nanocrystals changes in a complex way with rise in heat-treatment temperature. Characteristic times of luminescence decay, values of ground-state absorption cross-sections, and absorption saturation recovery time were determined. The developed glass-ceramics are promising as saturable absorbers for 1.6 µm erbium lasers.

Evaluation of Er:YAG and Er,Cr:YSGG laser irradiation for the debonding of prefabricated zirconia crowns.

Reduced tooth structure in the pediatric and adolescent population is frequently restored with prefabricated zirconia crowns. On permanent teeth, these restorations may need to be removed and replaced with permanent restorations. To explore and compare the use of 2 high-powered erbium lasers for removing prefabricated zirconia crowns from molar teeth as a non-invasive alternative to rotary instruments. Twenty-five permanent molars were prepared to dentin and prefabricated all-ceramic zirconia crowns were fitted and cemented with resin modified glass ionomer (RMGI) cement. The teeth were randomly assigned into one of the 2 retrieval treatment groups: the erbium-doped yttrium, aluminum and garnet (Er:YAG) laser group (G1; n = 12) or the erbium, chromium-doped yttrium, scandium, gallium and garnet laser (Er,Cr:YSGG) laser group (G2; n = 13). The laser operating parameters for the Er:YAG laser were 300 mJ, 15 Hz, 4.5 W, and 50-microsecond pulse duration (SSP mode); for the Er,Cr:YSGG laser, they were 4.5 W, 15 Hz, 20 water/20 air, and 5 W, 15 Hz, 50 water/50 air, and 60-microsecond pulse duration (H mode). The experiment was repeated twice. The surface area and the volume of teeth and crowns were measured and the cement space was calculated. The retrieval time and temperature changes were tested and recorded. The data were analyzed with the t-test. The surfaces of the dentin and the crown from each group were further examined using scanning electron microscopy (SEM). The average time for crown removal using the Er:YAG laser was 1 min 32.7 s; for the Er,Cr:YSGG laser it was 3 min 13.9 s (p < 0.0001). The mean temperature changes were 1.41 ±1.36°C for the Er:YAG laser and 2.2 ±0.99°C for the Er,Cr:YSGG laser (p = 0.0321). The SEM examination showed no damage or major structural changes caused by treatment with either erbium-family laser. Both lasers are effective, non-invasive tools to remove prefabricated zirconia crowns cemented with resin cement and should be considered as viable alternatives to rotary instrumentation.

Effect of casein-phosphopeptide amorphous calcium phosphate and fluoride with/without erbium, chromium-doped yttrium, scandium, gallium, and garnet laser irradiation on enamel microhardness of permanent teeth

Laser therapy, along with the use of fluoridated compounds is a novel technique suggested for caries prevention. Casein phosphopeptide amorphous calcium phosphate (CPP-ACP) is another product suggested for this purpose. This study compared the effect of CPP-ACP and fluoride with/without Erbium, chromium-doped yttrium, scandium, gallium, and garnet laser irradiation on enamel microhardness of permanent teeth. This in vitro experimental study evaluated 35 extracted third molars. The teeth were decoronated, and the crowns were split into buccal and lingual halves. The samples were randomly divided into seven groups (n = 10) of GC Tooth Mousse, MI Paste Plus, laser, fluoride varnish, laser + GC Tooth Mousse, laser + MI Paste Plus, and laser + fluoride varnish. The baseline microhardness was measured before the intervention. After the intervention, the samples were kept in artificial saliva for 1 h and were then immersed in the demineralizing solution for 3 h followed by 21 h of immersion in the remineralizing solution for a total period of 12 days. Finally, the teeth were kept in the remineralizing solution for 2 more days. The secondary microhardness of the teeth was then measured. Data were analyzed using the Shapiro-Wilk test, two-way ANOVA, and Tukey's Honestly Significant Difference test. The fluoride varnish (14.31%) and laser + fluoride varnish (18.79%) groups experienced minimum reduction in microhardness, while the GC Tooth Mousse group experienced maximum reduction in microhardness (91.64%) (P < 0.001). Laser irradiation before the application of remineralizing agents increased the microhardness only in laser + GC Tooth Mousse group (P < 0.001). Fluoride varnish increased the enamel microhardness, while GC Tooth Mousse had no such effect. Laser therapy before the application of remineralizing agents did not significantly enhance enamel resistance to demineralization.

Comparison of Live Bacteria Aerosolization during Removal of Dental Enamel Using a 9.3μm CO2 Laser, a 2.78μm Erbium Laser and a High-Speed Dental Drill

Purpose: To measure the amount of viable pathogens in the aerosol/splatter generated during dental procedures using lasers and high-speed drill. Methods: Three systems were used in this in vitro study: 9.3μm CO2 laser, 2.78μm erbium laser and a high-speed drill. 45 uncleaned human molars were randomly selected to be used for the test groups for the three systems. Bacteria ejected while cutting the buccal or lingual surfaces were collected on tryptic soy agar (TSA) plates in identical conditions for each measurement. On the opposite surface of each tooth, a non-cutting mist spray was applied. Results: The CO2 laser resulted in colony-forming units (CFU) with a mean of 1570 ± 3850 CFU/m3/s, which is statistically different (p &lt; 0.001) relative to both the erbium laser and the drill with a mean of 185,000 ± 182,000 CFU/m3/s and 440,000 ± 496,000 CFU/m3/s, respectively. CFU measured from the non-cutting mist spray on the teeth was higher for the drill than for the lasers. Conclusion: The 9.3μm CO2 laser resulted in the lowest CFU in the aerosol/splatter during enamel removal as compared to that of the 2.78μm erbium laser and the traditional high-speed drill. Furthermore, the CO2 laser was the only system that did not increase aerosolization of bacteria while cutting compared to the non-cutting mist spray.

1.56 µm and 1.93 µm synchronized mode-locked fiber laser with graphene saturable absorber

Ultrafast pulse with short duration ranging from picosecond to femtosecond has extensive industrial and scientific applications. The laser cavity generates this ultrafast pulse, however, was typically designed to emit the light at wavebands such as at approximately 1.5–1.6 µm or 1.9–2.0 µm. This could be limited by the bandgap of certain saturable absorber material to conduct ultra-broadband laser emission. Graphene, a 2D material with gapless band structure contributes to the optical resonant excitation to emit at any wavelength. The graphene was employed as the saturable absorber and positioned in a laser cavity consisting of both erbium and thulium-doped fiber laser. A synchronized mode-locked fiber laser was generated at a centre wavelength of 1563.5 nm and 1931.9 nm, giving a pulse duration of 700 fs and 1.77 ps at a constant pulse repetition rate of 12.905 MHz. The success of this work will provide a better insight by developing the optimum utilization of a saturable absorber in generating multiple mode-locked lasers with different yet far wavelength in near-infrared red region.

The use of Er:YAG Laser for dental caries removal

Background Carious tissue removal in enamel and dentin requires the use of sharp and resistant instruments. New tools have appeared to optimize/facilitate dental treatment, among them the laser. Regarding laser application for dental caries removal, the use of erbium laser doped with yttrium, aluminum, and garnet (Er:YAG) stands out. The Er:YAG laser is excellent for hard tissues ablation since its wavelength of 2.940nm is highly absorbed by water and hydroxyapatite. Objective To review the application of the Er:YAG laser in dental caries removal, to present its advantages and limitations in clinical practice, as well as to describe its action mechanism, and to compare its effectiveness with different methods used to remove caries. Data sources The search for articles to compose this literature review was carried out in the PubMed and Embase databases. Study selection Articles in English published between 2006 and 2021. The manual search included additional articles and books; a total of 39 references were selected. Data extraction Information from studies that evaluated the use of the Er:YAG laser to remove caries or related this type of laser to other methods. Articles that evaluated characteristics of the dental structure, or the influence of restorative materials after caries removal with the Er:YAG laser, were also considered. Study selection Based on studies results, the Er:YAG laser presents itself as an alternative for caries removal since it can remove demineralized tissue (selective ablation) without causing damage to the dental element.

An in-vitro study on the effectiveness of different irrigation solutions against Enterococcus faecalis with/without Erbium laser activation

An in-vitro study on the effectiveness of different irrigation solutions against Enterococcus faecalis with/without Erbium laser activation

Combined use of laser therapy and autologous plasma with cells in patients with post-acne atrophic scars

Background. Acne scar formation is a common consequence of acne vulgaris, in most cases atrophic scars resulting from tissue loss caused by inflammation of the pilosebial units.&#x0D; Aims: To study the effectiveness of combined laser therapy with Nd:YAG laser and Er: YAG laser with autologous plasma with cells in patients with different phenotypes of post-acne atrophic scars.&#x0D; Materials and methods. Depending on the method of treatment of post-acne scars, the patients were divided into 2 groups: Group 1 (n=28) with ice pick scars 10 patients; boxcar 9 patients; rolling 9 patients and group 1 (n=30) among them with ice pick scars 10; boxcar 9; rolling 11 patients. In group 1A, phototherapy was performed using a combination of Nd:YAG laser and Er:YAG laser. Immediately after laser exposure, autologous plasma was applied to the skin of the face of group 1B patients. To assess the effectiveness, the Manchester scale of assessment of scar deformities was used. The effectiveness was also evaluated using the Global Aesthetic Scale (GAIS) on a 3-point system. In this study, cutometry and ultrasound were performed to assess the elasticity of the skin in the foci of atrophy.&#x0D; Results. The indicator "color" on the MSS scale improved in the 1st group by 54.8%, in the 2nd by 83.7%, the indicator "texture" by 57.1 and 78.1%, the indicator "relief" by 43.8 and 66.7%, the indicator "displacement" by 54.9 and 82.1%, respectively. There were no patients with a deterioration or lack of effect on the GAIS scale in any of the study groups. According to the ultrasound scan data, the greatest effectiveness was observed in the group of complex treatment .&#x0D; Conclusion. Complex treatment, including the use of combined laser therapy (erbium and neodymium lasers) and autologous plasma with cells, is a highly effective technique for the treatment of atrophic post-acne scars.

A multi-wavelength pulsed mid-infrared laser based on Er:YAG

Highly doped erbium crystals have complex fine energy levels, which can be used to emit lasers of different wavelengths under different conditions. The mid-infrared multi-wavelength laser of erbium ions has not yet achieved stable laser emission. In this study, the rate equation is used, with consideration of mode competition, to design a mid-infrared Er:YAG pulsed laser that emits four wavelengths at room temperature. The gain of the multi-wavelength erbium laser is related to the Boltzmann distribution coefficient. Based on this, the conditions for multi-wavelength output have been calculated and verified in experiments. A four-wavelength stable output mid-infrared pulsed laser based on Er:YAG was produced. This laser may be applied to remote sensing or gas detection.

Repair bond strength and surface topography of resin-ceramic and ceramic restorative blocks treated by laser and conventional surface treatments.

This study intended to compare the repair bond strength of computer-aided design/computer-aided manufacturing (CAD/CAM) blocks consisting of resin and feldspathic ceramics following different surface treatments using the microtensile bond strength (μTBS) test. Ten specimens were prepared with 4 mm height for Vita Enamic (VE), Lava Ultimate (LU), Vita Mark II (VM), and thermocycled (10,000 cycle, 5-55°C). Each material was categorized into one of five subgroups according to following surface treatments: (a) bur grinding (BG), (b) hydrofluoric acid etching (HF), (c) neodymium-doped yttrium aluminum garnet (Nd:YAG or NY), (d) erbium-doped yttrium aluminum garnet (Er:YAG or EY), and (e) erbium, chromium-doped yttrium, scandium, gallium, and garnet (Er,Cr:YSGG or ECY) laser conditioning. After surface treatment procedures, specimens were properly restored to 4 mm high with a micro-hybrid composite resin. Bar specimens (1 × 1 × 8 mm) were obtained using a low-speed cutting machine and then thermocycled (10,000 cycle, 5-55°C). The μTBS was tested at 1 mm/min crosshead speed, and failure modes were evaluated. Data were analyzed with two-way ANOVA and post hoc Tukey tests. LU-BG showed significantly higher μTBS (32.94 ± 5.80 MPa) compared to LU-laser groups (p < .05). VE-BG showed significantly higher μTBS (22.06 ± 4.26 MPa) compared to other VE groups (p < .05). Among the laser groups, the NY laser produced the lowest (p < .05) μTBS for LU (13.42 ± 3.44 MPa) and VE (2.27 ± 0.85 MPa), while EY showed the highest (p < .05). Laser-treated VM groups were all prefailured. VM-HF produced a higher μTBS (18.73 ± 3.75 MPa) than VM-BG (5.05 ± 1.76 MPa) (p < .05).