Effect Of Er Research Articles

The Effect of Viloxazine Extended-Release Capsules on Functional Impairments Associated with Attention-Deficit/Hyperactivity Disorder (ADHD) in Children and Adolescents in Four Phase 3 Placebo-Controlled Trials.

PurposeThe ADHD Rating Scale (ADHD-RS) assesses 18 symptoms of inattention and hyperactivity/impulsivity and has been used in many clinical trials to evaluate the treatment effect of drugs on ADHD. The fifth edition of this scale (ADHD-RS-5) also assesses the impact of inattention and hyperactivity/impulsivity symptoms on six domains of functional impairment (FI): family relationships, peer relationships, completing/returning homework, academic performance at school, controlling behavior at school, and self-esteem. Here, we report the effect of viloxazine extended-release capsules (viloxazine ER), a novel nonstimulant treatment for ADHD in children and adolescents (ages 6–17 years), on FI from a post hoc analysis of four randomized, double-blind, placebo-controlled Phase 3 clinical trials (N=1354).Patients and MethodsADHD-RS-5 investigator ratings of ADHD symptoms and FIs were conducted at baseline and weekly post-baseline for 6–8 weeks in the four trials. Change from baseline (CFB) in ADHD-RS-5 FI scores (Total score [sum of 12 FI items] and Inattention and Hyperactivity/Impulsivity subscale scores [sum of 6 corresponding FI items]) and the 30% and 50% Responder Rates (ADHD-RS-5 FI Total score) were compared between viloxazine ER and placebo.ResultsThe reduction (improvement) in ADHD-RS-5 FI scores (Total and subscale scores) and the percentage of responders (30% and 50%) at Week 6 were significantly greater in each viloxazine ER dose group vs placebo. In the 100–400 mg/day viloxazine ER groups, improvements were found as early as Week 1 (100-mg/day) or Week 2 (200-, 400-mg/day) of treatment. Analysis of individual items of ADHD-related FIs demonstrated that the effect of viloxazine ER was observed across all domains of impairment.ConclusionSignificant improvements observed in ADHD-related FIs are consistent with the reduction in inattention and hyperactivity/impulsivity symptoms demonstrated in the viloxazine ER Phase 3 pediatric trials. Therefore, viloxazine ER provides clinically meaningful improvement of ADHD symptoms and functioning in children and adolescents with ADHD, starting as early as Week 1–2 of treatment.

Effect of Er:YAG laser pulse duration on repair bond strength of resin-based and hybrid CAD/CAM restorative materials

Besides the output power and pulse frequency, the pulse duration of Er:YAG laser is an important parameter for conditioning the restorative material surface. This study aimed to investigate the effect of six different pulse modes of Er:YAG laser on the repair bond strength of a hybrid ceramic and two resin-based CAD/CAM restorative materials. Twenty-eight specimens (5 × 5 × 4 mm) were prepared for each CAD/CAM block (Lava Ultimate-(LU), Vita Enamic-(VE), and GC Cerasmart-(GCC)) and randomly divided into seven groups. The specimens except the control group were irradiated using Er:YAG laser at 3 W and 20 Hz using quantum square pulse (QSP), super short pulse (SSP), short pulse (SP), medium short pulse (MSP), long pulse (LP), and a very long pulse (VLP). A micro-hybrid resin composite (Filtek Z250, 3 M ESPE, USA) was placed up to 4 mm on each CAD/CAM specimen in two increments. Bar specimens (1 × 1 × 8 mm) were obtained using a cutting device and thermocycled 10,000 times at 5–55 °C. Microtensile bond strength (µTBS) test was performed at a 1 mm/min crosshead speed. Data were statistically analyzed using two-way ANOVA and Tukey’s HSD tests (p < 0.05). µTBS was significantly affected by both pulse duration and material type (p < 0.001). Pulse duration and material type showed a statistically significant interaction (p < 0.001). Except for QSP, shorter pulse modes resulted in a higher repair bond strength. VLP mode is not recommended to be used in repair procedures with the materials tested.

The Effect of Er:YAG Lasers on the Reduction of Aerosol Formation for Dental Workers.

Infection prevention in dental practice plays a major role, especially during the COVID-19 pandemic. This study aimed to measure the quantity of aerosol released during various dental procedures (caries and prosthetic treatment, debonding of orthodontic brackets, root canal irrigation) while employing the Er:YAG lasers combined with a high-volume evacuator, HVE or salivary ejector, SE. The mandibular second premolar was extracted due to standard orthodontic therapy and placed in a dental manikin, to simulate typical treatment conditions. The particle counter was used to measure the aerosol particles (0.3–10.0 μm) at three different sites: dental manikin and operator’s and assistant’s mouth area. The study results showed that caries’ treatment and dental crown removal with a high-speed handpiece and the use of the SE generated the highest aerosol quantity at each measured site. All three tested Er:YAG lasers significantly reduced the number of aerosol particles during caries’ treatment and ceramic crown debonding compared the conventional handpieces, p < 0.05. Furthermore, the Er:YAG lasers generated less aerosol during orthodontic bracket debonding and root canal irrigation in contrast to the initial aerosol quantity measured in the dental office. The use of the Er:YAG lasers during dental treatments significantly generates less aerosol in the dental office setting, which reduces the risk of transmission of viruses or bacteria.

Effect of Er:YAG Laser and Association of Protocols on the Demineralized Enamel Microhardness.

Objective: The aim of this study was to analyze the microhardness of demineralized enamel following different treatments (fluoride varnish, Er:YAG laser, and Er:YAG laser associated with fluoride varnish). Methods: Forty-eight enamel blocks (4 × 4 × 7 mm) were divided into six groups (n = 8): (S) Sound; (DE) Demineralized; (DED) DE + Duraphat® 5% (fluoride varnish); (DEL20) DE + Er:YAG laser (20 mJ pulse mode; 0.20 W; 10 Hz; 60 sec; 1.18 J/cm2; 11.83 W/cm2); (DEL50) DE + Er:YAG laser (50 mJ pulse mode; 0.50 W; 10 Hz; 60 sec; 2.95 J/cm2; 29.58 W/cm2); (DEL20D) DE + Er:YAG laser (20 mJ) + Duraphat 5%. The irradiation was performed at 1 mm distance from the surface using a tip (AS7066X, L-14 mm, D-1.3 mm in diameter) in water/air spray refrigeration (level 6). The enamel blocks were submitted to pH cycling (4 h into DES solution +20 h into RE solution for 8 days and the solutions were changed every day). Knoop microhardness was measured (50 g/15 sec, six readings per sample) and data were analyzed by Kruskal-Wallis test at 5% significance. Results: After treatments, DF group showed higher microhardness values than all the groups. Also, DEL20D group showed similar results with H group according to the microhardness analysis (p < 0.05). Conclusions: It could be concluded that Duraphat 5% treatment showed better results when compared with all tested groups, however, the association of Er:YAG Laser 20 with Duraphat 5% also showed promising results.

Evaluation of Efficacy of Various Surface Conditioning Methods on the Repair Bond Strength of Composite to Different Fracture Types of Zirconia Ceramics.

The aim of this study was to investigate the effects of different surface treatment methods on shear bond strength between composite resin and different levels of zirconia ceramic. Laser surface-conditioning procedures have been reported as effective method to increase repair bond strength of composite to zirconia ceramics. Detailed information of effects of Er,Cr:YSGG laser treatment with different pulse rates on the zirconia ceramics is lacking in the literature. 120 disc-shaped specimens were prepared including zirconia, veneering ceramic, and 50% veneering ceramic-50% zirconia surfaces. Four different surface treatments were applied to the specimens. These were grinding with diamond bur, sandblasting, and short and long pulse rates of Er,Cr:YSGG laser irradiation. An intraoral ceramic repair kit was used to repair specimens, and shear bond strength was performed on the composite resin to each specimen. The highest mean bond strength was seen in the veneering ceramic surface that was ground using a diamond bur, and the lowest mean bond strength value was observed in the same surface that was treated with long pulse laser irradiation. The sandblasting with alumina particles exhibited lower mean repairing bond strength among the rest of used methods in this study for the group which contained half of the veneering ceramic and half of the zirconia. Sandblasting and Er,Cr:YSGG laser using surface treatment procedures obtained appropriate bond strength for the group that included 50% veneering ceramic-50% zirconia, because of no significant differences observed among the applied surface conditioning methods in this group.

The Effect of Erbium-Doped Yttrium Aluminum Garnet Laser in Debonding of Orthodontic Brackets: A Systematic Review of the Literature.

Objective: The purpose of this review is to systematically assess the existing literature and summarize the evidence regarding the effect of erbium-doped yttrium aluminum garnet (Er:YAG) laser on enamel surface roughness and pulp health compared with the conventional orthodontic debonding techniques. Materials and methods: Following the preferred reporting items for systematic reviews (Preferred Reporting Items for Systematic Reviews and Meta-analyses) statement, the electronic database, PubMed, Scopus, Web of Science, Google scholar, and Saudi Digital Library were searched for relevant published records. Data were collected following specific keywords: "debonding" "Er:YAG laser" etc. In vitro studies, and clinical randomized- and nonrandomized-controlled studies limited to the English language and published in peer-reviewed journals were included. Results: A total of 564 articles were identified as relevant to the topic. Duplicates were excluded resulting in 382 articles, out of which 374 articles were discarded upon screening titles and abstracts. The remaining eight articles were read to their entirety and included in the current qualitative review after fulfilling the eligibility criteria. In all the included studies, a total of 480 sound posterior teeth were used to evaluate the effect of Er:YAG laser on debonding of orthodontic brackets from the enamel surface. Conclusions: Er:YAG laser debonding has demonstrated a reduced risk of enamel damage (fracture or cracks) but resulted in increased enamel surface roughness and was time-consuming for adhesive removal procedures compared with the conventional debonding methods. Further, within the applied laser settings, Er:YAG lasers have found to exhibit low thermal exhaustion in relation to the pulp. The laser source with a wavelength of 2940 nm has been used with different setting ranges (power of 2.5-5 W, energy 125-600 mJ, frequency 4-30 Hz, and pulse duration 50-350 μsec) for debonding of orthodontic brackets.

In vitro effect of Er,Cr:YSGG laser on microtensile bond strength of composite resin to dentin using two different bonding systems

In vitro effect of Er,Cr:YSGG laser on microtensile bond strength of composite resin to dentin using two different bonding systems

Effect of Fe&lt;sup&gt;3+ &lt;/sup&gt;Partial Substitution at Mn-Site on Electroresistance Behaviour in La&lt;sub&gt;0.7&lt;/sub&gt;Ba&lt;sub&gt;0.3&lt;/sub&gt;Mn&lt;sub&gt;1-x&lt;/sub&gt;Fe&lt;sub&gt;x&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; (&lt;i&gt;x&lt;/i&gt; = 0 and 0.02) Manganites

La0.7Ba0.3Mn1-xFexO3 (x = 0 and 0.02) were prepared by using solid state synthesis method to investigate the effect of Fe3+ substitution at Mn-site on electrical behaviour and structural properties. An analysis of X-ray diffraction, XRD data using refinement method shown both x = 0 and x = 0.02 samples were in single phased and crystallized in rhombohedral structural with Pnma space group. From ρ vs T curves shown resistivity decreased under increased of applied current of 10 mA to 20 mA for both samples in the temperature range of 20 K-300 K. The larger electroresistance, ER effect observed for x = 0.02 in temperature range of 20 K – 180 K compared to x = 0 sample is suggested due to the development of filamentary conduction path under increased of applied current. It is suggested that Fe substitution enhanced magnetic inhomogeneity which contribute to the growth of formation of conductive path under increased of applied current, lead to increase of ER effect. In the temperature range of 180 K – 300 K, the observed decreased in ER for Fe substituted sample (x = 0.02) is suggested due to the increased of scattering effect and reduction of available hopping site in metallic region and insulating region, respectively. Restriction in the movement of charge carrier had weakened the ER effect for Fe substituted sample. The observed ER effect indicates the compound has a potential for application such as for non-volatile memory elements.

Electroresistance Effect due to Mo Substitution at Mn-Site in Monovalent Doped La&lt;sub&gt;0.85&lt;/sub&gt;Ag&lt;sub&gt;0.15&lt;/sub&gt;Mn&lt;sub&gt;1-&lt;/sub&gt;&lt;i&gt;&lt;sub&gt;x&lt;/sub&gt;&lt;/i&gt;Mo&lt;i&gt;&lt;sub&gt;x&lt;/sub&gt;&lt;/i&gt;O&lt;sub&gt;3&lt;/sub&gt; (&lt;i&gt;x &lt;/i&gt;= 0.00 and 0.05) Manganites

The electroresistance, ER effect of La0.85Ag0.15Mn1-xMoxO3 (x = 0.00 and 0.05) samples prepared using solid method are investigated. The increased of applied current from 5 mA to 10 mA does not change the metal-insulator transition temperature, TMI for both samples however decreased the resistivity in the temperature region of 50 K – 300 K. Both samples exhibit large ER effect at low temperature region. At TMI, the ER value is 75.5% (x =0) and decrease to 34.15% (x = 0.05). However, at 300 K, the value of ER increases to 57 % for Mo substituted sample, and the value decreases to 6.4% for the x =0 sample. The enhanced ER effect at 300 K may be due to the growth of conductive filaments under increased applied current. The increase of applied current may perturb the arrangement of magnetic inhomogeneity induced by Mo substitution, result in reduction of resistivity and lead to the observation of ER effect. These findings suggest potential application of La0.85Ag0.15Mn1-xMoxO3 (x = 0.05) in spintronic devices.

The Effect of Er:YAG Laser on a Shear Bond Strength Value of Orthodontic Brackets to Enamel-A Preliminary Study.

We sought to evaluate the effects of Er:YAG laser (LightTouch, LightInstruments, Israel) conditioning on enamel roughness and shear bond strength of orthodontic brackets on enamel. Eighteen human molars (n = 9) and premolars (n = 9), were divided into 3 groups depending on the enamel conditioning method; Er:YAG laser (G1, n = 6), conventional etching with 37% orthophosphoric acid (G2, n = 6), Er:YAG laser combined with conventional etching (G3, n = 6). Er:YAG laser parameters were as follows: energy: 100 mJ, frequency: 10 Hz, exposure time: 10 s, applicator diameter: 600 μm, fluence: 35.37 J/cm2, distance: 1 mm away from a tooth, cooling: 80%. An MTS 858 MiniBionix® machine was used to determine the shear bond strength (MTS System, Eden Prairie, MN, USA). The enamel structure was assessed using X-ray microtomography (SkyScan 1172, Bruker, Kontich, Belgium). The highest values of shear bond strength were obtained in the G3 group (9.23 ± 2.38 MPa) and the lowest values in the G2 group (6.44 ± 2.11 MPa) (p < 0.05). A significant change in the enamel surface was noted after applying laser, reaching up to 9% of enamel thickness, which was not observed in the etched samples. Moreover, the Er:YAG laser-irradiated enamel surface was characterized by the greatest roughness. The combined use of an Er:YAG laser with a conventional etching improves the adhesion of composite materials to the tooth.

CSNK1G2 differently sensitizes tamoxifen-induced decrease in PI3K/AKT/mTOR/S6K and ERK signaling according to the estrogen receptor existence in breast cancer cells.

Tamoxifen (TAM) is a selective estrogen receptor modulator used for breast cancer patients. Prolonged use of tamoxifen is not recommended for some patients. In this study, we aimed to identify molecular targets sensitive to TAM using a genome-wide gene deletion library screening of fission yeast heterozygous mutants. From the screening, casein kinase 1 gamma 2 (CSNK1G2), a serine-/threonine protein kinase, was the most sensitive target to TAM with a significant cytotoxicity in estrogen receptor-positive (ER+) breast cancer cells but with only a slight toxicity in the case of ER- cells. In addition, tumor sphere formation and expression of breast stem cell marker genes such as CD44/CD2 were greatly inhibited by CSNK1G2 knockdown in ER+ breast cancer cells. Consistently, CSNK1G2 altered ERα activity via phosphorylation, specifically at serine (Ser)167, as well as the regulation of estrogen-responsive element (ERE) of estrogen-responsive genes such as CTSD and GREB1. However, ERα silencing almost completely blocked CSNK1G2-induced TAM sensitivity. In ER+ breast cancer cells, combined treatment with TAM and CSNK1G2 knockdown further enhanced the TAM-mediated decrease in phosphatidylinositol 3-kinase (PI3K)/AKT/mammalian target of rapamycin (mTOR)/ribosomal protein S6 kinase (S6K) signaling but not extracellular signal-regulated kinase (ERK) signaling. Inversely, in ER- cells treated with TAM, only ERK and PI3K signaling was altered by CSNK1G2 knockdown. The CK1 inhibitor, D4476, partly mimicked the CSNK1G2 knockdown effect in ER+ breast cancer cells, but with a broader repression ranging from PI3K/AKT/mTOR/S6K to ERK signaling. Collectively, these results suggest that CSNK1G2 plays a key role in sensitizing TAM toxicity in ER+ and ER- breast cancer cells via differently regulating PI3K/AKT/mTOR/S6K and ERK signaling.

Effect of endoscopic resection on short-term surgical outcomes of subsequent laparoscopic gastrectomy: a meta-analysis

BackgroundEndoscopic resection (ER) might affect subsequent laparoscopic gastrectomy (LG) because of the electrical coagulation, but the effect remains controversial. The purpose of this meta-analysis was to analyze the effect of ER on the short-term surgical outcomes of subsequent LG.Materials and methodsThe PubMed, EMBASE, and Cochrane Library databases were searched to find eligible studies published from inception to March 21, 2021. Short-term surgical outcomes were compared between the ER-LG group and the LG-only group. The registration ID of this current meta-analysis on PROSPERO is CRD42021238031.ResultsNine studies involving 3611 patients were included in this meta-analysis. The LG-only group had a higher T stage (T1-T2: OR=2.42, 95% CI=1.09 to 5.34, P=0.03; T3-T4: OR=0.41, 95% CI=0.19 to 0.91, P=0.03) than the ER-LG group. The ER-LG group showed a shorter operation time than the LG-only group (MD=−5.98, 95% CI=−10.99 to −0.97, P=0.02). However, no difference was found in operation time after subgroup analysis of propensity score matching studies. No significant difference was found in intraoperative blood loss, time to first oral feeding, or postoperative hospital stay between the ER-LG group and the LG-only group. And no significance was found in overall complications (OR=1.16, 95% CI=0.89 to 1.50, P=0.27), complications of grade ≥ II (OR=1.11, 95% CI=0.71 to 1.73, P=0.64), complications of grade ≥ III b (OR=1.47, 95% CI=0.49 to 4.43, P=0.49) between the ER-LG group and the LG-only group.ConclusionsER did not affect subsequent LG in terms of short-term outcomes, and the ER-LG group might have a shorter operation time than the LG-only group.

Effect of Er,Cr:YSGG Laser Versus Acid Etching Surface Treatment on the Surface Roughness and Topography of Two Pressable Lithium Disilicate Ceramics. “In-Vitro Study”.

Objective: To assess the effect of two surface treatment protocols of two pressable lithium disilicate ceramics with different thicknesses on the surface roughness and topography. Material and methods: Sixty four lithium disilicate ceramic discs were divided into two groups (n=32); IPS e.max Press and InitialTM LiSi Press. Each group was subdivided into two subgroups (n=16) according to thicknesses (0.5mm and 1mm). Each subgroup was divided into two subdivisions (n=8) according to the surface treatment; Er:Cr:YSGG Laser and hydrofluoric acid etching. Artificial aging was performed for all the specimens. Surface roughness (Ra) before and after surface treatment protocol was measured using contact stylus profilometer and their topographical changes were identified using scanning electron microscope. Results: there was no significant difference in Ra values between the two ceramic types before and after surface treatment. There was no significant difference in Ra values between the two surface treatments on both ceramics. There was a difference in the effect of the surface treatments on the topography of the ceramics Conclusion: Both surface treatments have comparable effect on the surface roughness of lithium disilicate ceramic but have different effect on the ceramic’s topography.

Microleakage of Cavity Class V Restored by Composite Resin and Conventional Flowable Composite Restorations in Primary Molars Conditioned by Er,Cr:YSGG Laser Versus Conventional method (An in Vitro Study)

Abstract Introduction: In modern operative dentistry in the field of pediatric dentistry Er,Cr:YSGG laser is suitable for cavity preparation in deciduous molars because it have many advantages. Microleakage is one of the major problems that influence the longevity for the resin-based dental restorations. The purpose of the current study is comparing the effect of Er,Cr:YSGG laser and conventional conditioning on the microleakage in cavity class V restored by composite resin and conventional flowable composite in deciduous molars. Materials and methods: A standard class V cavity were prepared at the buccal or lingual surface of forty-eight freshly extracted caries-free human deciduous molars which were divided into 2 groups according to the mode of conditioning: group 1: by using Er,Cr:YSGG laser; group 2: by using conventional conditioning. The samples were subjected to thermocycling and dying step. Results: Laser conditioning showed statistically significantly lower median microleakage scores than conventional technique (P-value = 0.001, Effect size = 1.923) and (P-value = 0.002, Effect size = 1.639), respectively. There was no statistically significant difference between median microleakage scores of the two composite types (P-value = 0.057, Effect size = 0.718) and (P-value = 0.108, Effect size = 0.658), respectively. Conclusion: Conditioning by Er,Cr:YSGG Laser is better than conventional method as regards microleakage and no significant difference between composite resin and conventional flowable composite clinically.

Bactericidal effect of Er,Cr:YSGG laser irradiation on endodontic biofilm: An ex vivo study

AimThis ex vivo study aimed to evaluate the of Er,Cr:YSGG laser effectiveness in the decontamination of an endodontic biofilm. Materials and methodsSeventy-three single rooted human teeth, freshly were chosen. Each tooth was exposed to four associated species in an endodontic biofilm (Enterococcus faecalis, Streptococcus salivarius, Porphyromonas gingivalis, and Prevotella intermedia) and randomly allocated to one of the seven experimental groups. The group 1 (7 teeth) was used to finalize the reliable biofilm-forming technique. The groups 2 and 3 (15 teeth each group) were irradiated with two different Er;Cr:YSGG laser settings (0,75 W - 40 Hz and 4 W - 40 Hz, respectively). The groups 4 and 5 (15 teeth each group) were irrigated with two different solutions and laser irradiated with the same settings (1,5 W - 15 Hz). The group 6 (6 teeth) was the control group treated only with 4 ml 2,5% NaOCl irrigation during 60 s. ResultsThe observations of group 2 and 3 specimens showed the ripeness of the biofilm with the presence of Enterococcus faecalis and Streptococcus salivarius in chains but in group 3 thermal edge effects produced by the optic fiber in the canal walls were present.The group 4 specimens observation showed an average cleaning of the root canal walls while on the canal walls of group 5 samples the apical third presented several debris and smear layer and in the centre cracks and melting dentin of the radicular wall were observed. ConclusionIn those experimental conditions, this study, demonstrated that Er,Cr:YSGG laser has a canals decontamination ability when associated to NaOCl irrigation.

Spectrophotometric evaluation of the effectiveness of Er,Cr:YSGG laser-assisted intracoronal tooth bleaching treatment using different power settings

BackgroundNon-vital tooth discoloration is a common condition in dental practice. The aim of this in vitro study was to evaluate the efficacy of intracoronal bleaching treatments of non-vital teeth either activated or not by Er,Cr:YSGG laser (2780 nm) operating at 1.25 or 2.5 W. MethodsTwenty four human canines were artificially stained after implementation of root canal treatment. Subsequently, the teeth were randomly divided into three groups (n = 8): Group 1 (control) received intracoronal bleaching treatment with a bleaching gel containing 35 % hydrogen peroxide for 40 min, Group 2 received the same treatment assisted with Er,Cr:YSGG laser (2780 nm) operating at 1.25 W average power for 30 s and Group 3 received the same treatment with Group 2, but the average power was adjusted to 2.5 W. The bleaching treatments repeated after one week. Spectrophotometric analysis of tooth color change (ΔE) was implemented 7 days after both bleaching sessions. ResultsThe results of two-way ANOVA revealed that there was a tendency of no significant difference in color change between the three experimental groups (p = 0.063). However, the between-group comparisons showed that laser 2.5 W group had significantly higher ΔE than the control group after the first bleaching session. Moreover, a significant interaction between bleaching treatment and number of applications was detected (p = 0.026). ConclusionsEr,Cr:YSGG laser irradiation significantly increased ΔE only after the first bleaching session when operating at 2.5 W. After the second bleaching session ΔE was not different compared to the control group, irrespectively of the laser power settings.

Mg17Al12 phase refinement and the improved mechanical performance of Mg–6Al alloy with trace erbium addition

With an improvement in room temperature ductility, the automotive use of cast Mg–Al alloys can be extended to structural body components. This is challenging since Al readily forms brittle intermetallics with the alloying additions such as rare earths and limits their solid solubility largely, nullifying the potential beneficial effects of rare earth elements on plasticity e.g. on stacking fault energy. In this study, significant improvement of mechanical properties in Mg-6wt% Al (Mg–6Al) casting alloy was seen with low levels of Er additions (60 ppm and 880 ppm) that was related to the modifying effect of Er on the Mg17Al12 precipitates and the α-Mg. Thermodynamic simulations, atom probe tomography, scanning electron microscopy, X-rays diffraction and mechanical testing were employed to understand the modification mechanism in Mg–6Al. According to Scheil solidification simulations, Al2Er Laves co-precipitates at the same temperature as Mg17Al12 exerting an inoculating effect when Er is at trace levels in the bulk alloy; however, when Er in the alloy increases, Al2Er forms at higher temperatures much before Mg17Al12 losing its inoculant potential. It was also seen that Er is soluble in Mg17Al12 causing changes to its lattice parameter and cell volume. Tensile strength, ductility, compressive strain to fracture and hardness are influenced by microstructural refinement. Yield strength at the higher level of Er (880 ppm) can be explained by the existence of Er-rich intermetallics while the yield strength at low levels of Er (60 ppm) can more likely be explained by the nature of β-phase.

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.

Effects of Er:YAG laser irradiation of different titanium surfaces on osteoblast response

The aim of this in vitro study was to evaluate the effects of erbium-doped yttrium aluminum garnet (Er:YAG) laser irradiation on titanium surface topography and the proliferation and differentiation of osteoblasts using standard clinical treatment settings. Er:YAG laser irradiation at two levels ((1): 160 mJ, pulse at 20 Hz; (2): 80 mJ, pulse at 20 Hz) was applied to moderately rough and smooth titanium disks before MG-63 osteoblast-like cells were cultured on these surfaces. Titanium surface and cell morphology were observed by scanning electron microscopy. Cell proliferation/viability was measured by CCK-8 test. Gene expression of alkaline phosphatase (ALP), osteocalcin (OC), osteoprotegerin (OPG), receptor activator of nuclear factor kappa-B ligand (RANKL), and collagen type 1 was measured by qPCR, and OPG and OC protein production was determined by enzyme-linked immunosorbent assay. Treatment with Er:YAG laser at 160 mJ/20 Hz markedly caused heat-induced fusion of titanium and cell condensation on moderately rough surfaces, but not in smooth surfaces. MG-63 proliferation/viability decreased after 5 days in moderately rough surfaces. The expression of ALP, OC, OPG, and collagen type 1 was unaffected by laser treatment at 160 mJ/20. Laser irradiation at 80 mJ/20 Hz enhanced RANKL gene expression after 5 days in moderately rough surfaces. Study results suggest that Er:YAG laser irradiation at clinically relevant setting has no essential effect on osteogenic gene and protein expression of osteoblasts. However, surface structure, cell attachment, and proliferation are influenced by both treatment protocols, which implies that caution should be taken in the clinical treatment of peri-implant diseases when Er:YAG laser is used.

Efficiency of Erbium-Doped Yttrium Aluminum Garnet Laser in Debonding Cemented Glass Fiber Posts: an in vitro Study.

Statement of the Problem: The efficacy of erbium-doped yttrium aluminum garnet (Er; YAG) laser on the debonding properties of certain post materials has remained largely unexplored. Purpose: This study aimed to investigate the effect of Er; YAG laser irradiation on debonding of cemented glass fiber posts in root canal treated teeth.Materials and Method: In this in vitro study, forty root canal treated mandibular premolar teeth were used in this study. Glass fiber posts were bonded using Panavia F 2.0 cement in the root canal space, and samples were divided into two groups. In the test group, samples were exposed to laser radiation of 7W, 350mJ, frequency of 20Hz and discontinued washing spray. In the control group, samples were left untouched. In each group, samples were sectioned into 1.5mm thick slices from the coronal, middle, and apical thirds of the root (N=120). Tensile bond strengths were evaluated using the push-out test and the failure patterns were evaluated using scanning electron microscopy (SEM). To compare the laser and non-laser groups at each location, independent sample t test was applied, and to compare bond strength between the locations in each group, one-way ANOVA and Tukey’s HSD post hoc was applied.Results: A significant difference in tensile strength was observed between the laser-irradiated group and control group; tensile bond strength was much higher in the control group (p<0.001). The highest frequency of fractures was observed at the cement-dentin interface. Given the used parameters, complete debonding was not achieved in the laser-irradiated group.Conclusion: Laser radiation reduced the bond strength of glass fiber posts to resin cement without complete debonding.