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The safety and efficacy of laser hair removal have been well established through many clinical studies and through clinical use over the past 25 years. A laser hair removal device that protects the epidermis by utilizing cryogen spray cooling (CSC) is widely used internationally. In darker skin types, post-inflammatory hyperpigmentation (PIH) can occur after laser hair removal. In particular, laser hair removal with CSC is known to cause crescent-shaped or ring-shaped PIH. In this experiment, we report a visualization of this PIH mechanism. The laser used in this experiment is a 755-nm-long-pulsed alexandrite laser. Graph paper was treated with this laser to assess for thermal damage. We investigated changes in thermal damage due to differences in laser spot size, fluence output, and laser beam angle in relation to the graph paper. When using a spot size of 18 mm, we observed that higher fluences caused crescent-shaped thermal damage on the margins of the treated graph paper. It was also confirmed that when the hand piece is not held perpendicular to the skin, the laser-treated area is expanded and the CSC range is narrowed. These factors caused the area of thermal damage to widen. This widening causes ring-shaped thermal injury, leading to PIH. We treated graph paper using a hair removal laser with CSC to investigate the mechanism of crescent or ring-shaped thermal damage. Laser treatment on graph paper is effective as a test for defects in the CSC device. Factors that cause inadequate cooling, which leads to PIH, are large spot size, high fluence, not holding the laser hand piece perpendicular to the skin, and malfunctioning of CSC device. [ABSTRACT FROM AUTHOR]

Aim: The aim of the present study was to evaluate the efficacy of 30°-angled Er:YAG laser tip and different periodontal instruments on root surface roughness and morphology in vitro. Methods: Eighteen bovine teeth root without carious lesion were decoronated from the cementoenamel junction and seperated longitidunally. A total of 36 obtained blocks were mounted in resin blocks and polished with silicon carbide papers under water irrigation. These blocks were randomly assigned into 3 treatment groups. In Group 1, 30°-angled Er:YAG laser (2.94 μm) tip was applied onto the blocks with a 20 Hz, 120 mJ energy output under water irrigation for 20 s. In Groups 2 and 3, the same treatment was applied to the blocks with new generation ultrasonic tip and conventional curette apico-coronally for 20 s with a sweeping motion. Surface roughness and morphology were evaluated before and after instrumentation with a profilometer and SEM, respectively. Results: After instrumentation, profilometric analysis revealed significantly higher roughness values compared to baseline in all treatment groups(p < 0.05). Laser group revealed the roughest surface morphology followed by conventional curette and new generation ultrasonic tip treatment groups (p < 0.05). In SEM analysis, irregular surfaces and crater defects were seen more frequently in the laser group. Conclusion: Results of the study showed that the use of new generation ultrasonic tip was associated with smoother surface morphology compared to 30°-angled Er-YAG laser tip and conventional curette. Further in vitro and in vivo studies with an increased sample size are necessary to support the present study findings. [ABSTRACT FROM AUTHOR]

Vital pulp therapy (VPT) is primarily intended to preserve the vitality of pulp tissues, which have been exposed for any reason. Various materials and techniques have been proposed to improve treatment outcomes, including the use of lasers. This study aimed to review the histological results of different dental lasers including low-level lasers, carbon dioxide (CO2), erbium-doped yttrium aluminum garnet laser (Er:YAG), neodymium-doped yttrium aluminum garnet (Nd:YAG), erbium, chromium:yttrium-scandium-gallium-garnet (Er,Cr:YSGG) lasers, and diode lasers for VPT. This focused review included a comprehensive electronic search of Scopus, MEDLINE, Web of Science, and Google Scholar databases from 2000 to 2022 by two independent investigators. Different combinations of keywords were used, and reference mining of related papers was done. The review included studies related to histologic evaluation of laser-assisted vital pulp therapy that stated the laser parameters that were used. Articles with radiographic or clinical assessments or articles lacking necessary data were excluded. Non-English articles were excluded unless their abstract was in English and encompassed the necessary data. Most studies indicated the efficacy of lasers for reduction of inflammation, acceleration of healing, and increasing the thickness of dentinal bridge. According to the evidence, lasers used in combination with pulp capping agents are beneficial to enhance the success rate of VPT. [ABSTRACT FROM AUTHOR]

Laser therapies have been well-established in ameliorating skin-aging consequences. This systematic review aims to determine the efficacy, safety profile, and satisfaction rates of laser combination therapies on skin rejuvenation resurfacing. A systematic search was performed in four major databases up to September 2022. Skin rejuvenation studies were eligible comprising at least one laser combination arm, inclusive of all laser types (ablative or non-ablatives), and one monotherapy arm selected from one of the combined modalities. Studies combining one laser modality with radiofrequency (RF) or intense pulse light (IPL) were also assessed. Trials that did not encompass a monotherapy control arm were evaluated independently as single-arm studies. Eighteen clinical trials recruiting 448 cases were included after screening. A total of 532 nm KTP + 1064 nm Nd:YAG and 2940 nm Er:YAG + Nd:YAG were the two most utilized laser combinations and exerted higher improvements and milder adverse events, compared to their monotherapy in most studies. Combining CO2 with rhodamine-IPL or gallium arsenide laser increased efficacy and satisfaction and brings about faster skin recovery time. Augmenting CO2 + RF did not increase improvement vs CO2 laser alone but prolonged skin erythema. Our meta-analysis revealed the pooled prevalence of quartile improvement rates as 0%, 28%, 40%, 27% in laser combination group, and 0%, 9%, 31%, 17% in laser monotherapy group, respectively. The satisfaction within each quartile category was 39%, 25%, 15%, 7% in laser combination and 20%, 25%, 16%, 17% in laser monotherapy, respectively, suggestive of the higher efficacy and satisfaction of laser combination group. The pain scores were lower in laser combination group than monotherapy (4.8 ± 1.18 vs 7.18 ± 0.7, converted on a scale of 0 to 10). Post-laser skin erythema lasted less longer in the combination group (12.8 vs 15.24 days). Laser combination therapies were discovered to be superior to their monotherapies in terms of clinical improvement rates, diminished adverse events such as pain and erythema and patients satisfaction rates. Due to paucity of high-quality reportings, additional trials are warranted to corroborate these results. [ABSTRACT FROM AUTHOR]

Thermal effects during bone surgery pose a common challenge, whether using mechanical tools or lasers. An irrigation system is a standard solution to cool the tissue and reduce collateral thermal damage. In bone surgery using Er:YAG laser, insufficient irrigation raises the risk of thermal damage, while excessive water lowers ablation efficiency. This study investigated the potential of optical coherence tomography to provide feedback by relating the temperature rise with the photo-thermal expansion of the tissue. A phase-sensitive optical coherence tomography system (central wavelength of λ=1.288 μm, a bandwidth of 60.9 nm and a sweep rate of 104.17 kHz) was integrated with an Er:YAG laser using a custom-made dichromatic mirror. Phase calibration was performed by monitoring the temperature changes (thermal camera) and corresponding cumulative phase changes using the phase-sensitive optical coherence tomography system during laser ablation. In this experiment, we used an Er:YAG laser with 230 mJ per pulse at 10 Hz for ablation. Calibration coefficients were determined by fitting the temperature values to phase later and used to predict the temperature rise for subsequent laser ablations. Following the phase calibration step, we used the acquired values to predict the temperature rise of three different laser-induced cuts with the same parameters of the ablative laser. The average root-mean-square error for the three experiments was measured to be around 4 °C. In addition to single-point prediction, we evaluated this method's performance to predict the tissue's two-dimensional temperature rise during laser osteotomy. The findings suggest that the proposed principle could be used in the future to provide temperature feedback for minimally invasive laser osteotomy. [ABSTRACT FROM AUTHOR]

Implantable central venous (CV) ports are widely used for chemotherapy and parenteral nutrition. Generally, CV ports are used safely; however, some patients suffer from drug leakage around the port septum due to mispuncture. Therefore, we developed a CV port that is visible under the skin. We created a prototype of a CV port using a 3D printer. Three red light-emitting diodes (LEDs) were attached around the septum that made the puncture site visible by applying wireless energy transmission technology using electromagnetic resonance. The CV port was implanted under the skin of pork rose meat. The thickness of the skin of pork loin was measured. Fifteen medical doctors participated in the study to visually confirm the lighted CV port. The visibility of the center of the septum with and without lights was scored 0 as non-diagnostic; 1, slightly visible; 2, well visible; and 3, obviously visible. The visibility with or without lights was assessed. The relationship between the years of experience and the visibility score was assessed. The Wilcoxon test was used for statistical analysis. LEDs were easily transmitted through the skin of pork rose meat. The median visibility scores with or without lights were 2 (range, 1–3) and 3 (range, 1–3), respectively (p = 0.005). No significant relationship was found between experience and visibility score (p = 0.289). CV ports with LEDs can be easily recognized compared with those without LEDs. This technique may contribute to medical safety by improving its visibility to avoid mispuncture. [ABSTRACT FROM AUTHOR]

This study evaluated the effect of chitosan on dentin treatment after selective removal of caries lesions with Er:YAG laser in reducing Streptococcus mutans, as well as its effect on the performed restorations. The sample consisted of children (aged 7 to 9 years) with active carious lesions and dentin cavitation located on the occlusal surface of deciduous molars. Eighty teeth were randomly distributed into 4 groups according to the caries removal method: Er:YAG laser (250 mJ/4 Hz) or bur and dentin surface treatment: 2.5% chitosan solution or distilled water. The bacterial load of caries-affected dentin was quantified by counting CFU/mg (n = 10). The teeth were restored and evaluated at 7 days, 6 months, and 12 months using modified USPHS criteria (n = 20). Microbiological data was analyzed by Mann–Whitney and clinical analyses were done using Kruskal–Wallis and Dunn test (α = 0.05). The results showed that the Er:YAG laser significantly reduced the amount of Streptococcus mutans (p = 0.0068). After dentin treatment with chitosan, there was a significant reduction in the amount of Streptococcus mutans for both removal methods (p = 0.0424). For the retention and secondary caries criteria, no significant differences were observed along the evaluated time (p > 0.05). The laser-treated group was rated "bravo" for discoloration (p = 0.0089) and marginal adaptation (p = 0.0003) after 6 and 12 months compared to baseline. The Er:YAG laser reduced the amount of Streptococcus mutans and the chitosan showed an additional antibacterial effect. After 1 year, the Er:YAG laser-prepared teeth, regardless of the dentin treatment, showed greater discoloration and marginal adaptation of the restorations. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the efficacy of fluoride-free remineralizing agents in initial enamel caries, with and without combined Er,Cr:YSGG laser application. The remineralization effect of various agents and their combinations on artificial initial caries was investigated using 10 experimental groups (n = 7): NC, negative control; PC, positive control; TM, calcium-phosphate compounds (CPP-ACP); TD, theobromine-containing toothpaste; RG, ROCS® remineralizing gel; L, Er,Cr:YSGG laser (2780 nm; 0.25 W; repetition rate, 20 Hz; pulse duration, 140 μs; tip diameter, 600 μm; without air/water cooling); L + fluoride toothpaste; L + TM; L + TD; and L + RG. The demineralized bovine enamel specimens were subjected to an 8-day pH cycle by daily application of the remineralizing agents and laser therapy once prior to the pH cycle and paste application. The enamel samples underwent the Vickers surface microhardness test, and one sample per group was analyzed with scanning electron microscopy. The Kruskal Wallis test was used to compare the microhardness recovery percentage (SMHR%) for each group, and multiple comparisons were made with the Dunn test. Groups L (p = 0.003), RG (p = 0.019), L + TM (p < 0.001), L + fluoride toothpaste (p = 0.001),and L + RG (p = 0.036) exhibited significant increase in SMHR%. The tested remineralizing agents exhibited no statistically significant difference in effect when used alone and in combination with Er,Cr:YSGG laser. Combined application of Er,Cr:YSGG laser and ROCS® remineralization gel effectively promoted enamel remineralization, while use of CPP-ACP and fluoride toothpaste alone was ineffective. Theobromine-containing toothpaste exhibited the least SMHR%. Long-term evaluation of these agents is recommended. [ABSTRACT FROM AUTHOR]

We performed a narrative review with the focus on laser settings and surgical procedure with thulium laser. Our primary goal was to define the most valid settings of each surgical procedure to overcome the inconsistency about nomenclature of thulium surgery and to ensure comparability of future publications. A literature search of articles on thulium laser treatment of benign prostatic hyperplasia (BPH) was conducted between 2009 and 2019. We proposed a new classification standard for laser settings and associated surgical procedure. Each article was analyzed and categorized as concordant or discordant referring to the new classification. In total, 74 papers were included in this narrative review. Overall, 43% and 42% of included studies reported discordant laser parameters and surgical description, respectively. Most of the studies on vaporization were categorized as discordant because they reported a medium/low laser setting instead of high power. Conversely, 93.3% of studies on enucleation were deemed as discordant for laser setting because they reported high power parameters instead of medium-low power setting. Most of the studies on laser enucleation and vapo/enucleation were considered discordant for surgical procedure since authors did not mention the use of mechanical vs. laser method for enucleation. The current literature lacks a uniform definition and standardization of the terminology of thulium laser settings and surgical techniques to guarantee comparability between different approaches. We found a huge heterogeneity in 10 years of surgery with thulium laser. We proposed a new classification of laser setting and procedural description for categorization of thulium laser surgery for BPH. [ABSTRACT FROM AUTHOR]

The effects of neodymium:yttrium-aluminium-garnet (Nd:YAG) laser and silicon carbide (SiC) paper on the surface micro-topography of titanium-6 aluminium-4 vanadium (Ti6Al4V) alloy were examined in relation to the response of bone cells. The study was performed in three distinct stages: (1) after surface treatment of samples by laser and SiC paper, the surface hardness, surface roughness, corrosion resistance and surface tension were evaluated; (2) the growth of mouse connective tissue fibroblast cells (L-929) on untreated and treated samples was assessed in vitro; (3) the response of goat osteoblast cells to untreated and treated implanted samples was assessed in vivo. The surface roughness varied between 7 +/- 0.02 for laser-treated samples (LTSs) at 140 J cm(-2) and 21.8 +/- 0.05 for mechanically treated samples (MTSs). The surface hardness was found to vary from 377 Vickers hardness number (VHN) for MTSs to 850 VHN for LTSs. A corrosion potential of -0.21V was achieved for the LTSs compared with -0.51V for the MTSs. The LTSs exhibited a more hydrophilic behaviour (i.e. wettability) than did the MTSs. No cytotoxicity effect, unlike for the MTSs, was observed for the LTSs. The results of in vivo tests indicated longitudinal growth of osteoblast cells along the grooves on the samples formed by the SiC paper, and multidirectional spreading of the cells on the LTSs. [ABSTRACT FROM AUTHOR]

In this study, it was aimed to evaluate the smear and debris removal efficiency of laser and ultrasonic irrigation activation methods in traditional and conservative endodontic access cavity preparations. 60 freshly extracted human mandibular molar teeth were randomly divided into 2 groups according to the access cavity preparation (n = 30): Traditional endodontic access cavities (TEC) and Conservative endodontic access cavity (CEC). After the access cavity preparation, the mesiobuccal root canals were prepared to 35/0.4 with the VDW Rotate file system. Teeth with completed root canal preparation were randomly divided into 3 subgroups according to the final irrigation activation protocol (n = 30): Conventional needle irrigation, passive ultrasonic activation and laser activation. The crowns of the teeth were removed and the mesiobuccal roots were divided longitudinally into two halves, mesial and distal. Samples were scanned with scanning electron microscopy. Photomicrographs in the coronal, middle, and apical thirds of each specimen were taken at a magnification of 200 for debris and 1000 for evaluation of the smear layer. Data were analysed using the three-way Robust Anova test and Bonferroni test. The effect of access cavity design on remaining smear (p = 0.057) and debris (p = 0.5) was not statistically significant. The effect of the interaction of access cavity and irrigation activation on the remaining smear and debris was not statistically significant (p = 0.556, p = 0.333). Significantly fewer smears were detected in the laser activation group than in the ultrasonic activation and control groups. Conservative access cavities did not differ from conventional access cavities in terms of debris and smear. [ABSTRACT FROM AUTHOR]

Fiber post bonding failure remains an issue during crown restoration procedures. This experiment examines the bonding effect of combined Er:YAG laser treatment on both root canal and fiber post. Sixty extracted mandibular first premolars were randomly selected and divided into 6 groups (n = 10 per group): G1 (control group): root canal with 2.5% NaClO treatment, no treatment of fiber post; G2: root canal with 2.5% NaClO treatment and fiber post with airborne-particle abrasion; G3: root canal with Er:YAG laser treatment and fiber post with airborne-particle abrasion; G4: root canal with Er:YAG laser treatment, no treatment of fiber post; G5: root canal with 2.5% NaClO treatment, fiber post with Er:YAG laser irradiation; G6: combined Er:YAG laser irradiation of both root canal and fiber post. An Er:YAG laser with a wavelength of 2940 nm was used to treat the fiber post (4.5 W, 450 mJ, 10 Hz for 60 s at 100-μs pulse duration with 100% water cooling) and the root canal (1.5 W, 150 mJ, 10 Hz for 60 s at 100-μs pulse duration with 100% water cooling). When the root canal was treated with the laser, the fiber tip was inserted into the root canal to make a spiral reciprocating motion. Bond strength was analyzed by a micro push-out test. Data were analyzed using both the Tukey test and two-way ANOVA (α = 0.05). Failure modes were observed and counted through a stereo microscope. The root canal and fiber post surface analysis was performed using SEM. The bond strength of G3 and G6 were significantly enhanced compared to those of the other groups (p < 0.05). The SEM analysis showed that the smear layers of groups with root canals subjected to Er:YAG laser irradiation were significantly reduced compared to those of the control group (G1). In groups with fiber posts treated with Er:YAG laser irradiation, the surfaces of the fiber posts exhibited greater surface roughness and a certain degree of epoxy matrix removal. Through the combined Er:YAG laser irradiation of both root canal and fiber post, the bond strength between them was significantly enhanced, which was superior to the individual treatment of either fiber posts or root canal. [ABSTRACT FROM AUTHOR]

The purpose of the study was to determine the influence of preparation techniques on marginal adaptation and sealing of Biodentine™ and TotalFill® RRM bioceramic retrograde fillings. Fifty-two single-root teeth extracted for periodontal reasons were used. Root canals were instrumented using Reciproc Blue #25 and obturated using a single cone technique with an AH Plus® root canal sealer. Retrograde cavities were prepared with Piezomed device (Piezo), Er:YAG laser in short-pulse(SP) and quantum square pulse(QSP) modes and filled with Biodentine™ (BD) or TotalFill® RRM (TF). There were 6 groups (n=8): (1) Piezo BD, (2) Piezo TF, (3) SP BD, (4) SP TF, (5) QSP BD, and (6) QSP TF, and positive and negative controls (n=2). Micro-CT analysis was performed on two samples from each group. Percentage volumes of internal and external voids in apical 1.5 mm were determined. Rhodamine B dye leakage was done on six samples. The samples were cut longitudinally and examined under a stereomicroscope. Digital recordings were analyzed in ImageJ software. The deepest penetration of color in mm was recorded. The data were statistically analyzed using ANOVA and Duncan's test at the level of significance α=0.05. TotalFill® RRM performed significantly better than Biodentine™ in terms of sealing (p<0.05) and marginal adaptation, as evaluated by micro-CT. Sealing was significantly better in SP compared to QSP mode preparations (p<0.05). Differences between Piezomed and laser modes were not significantly different (p>0.05). Sealing was statistically significantly better with TotalFill® RRM compared to Biodentine™ and in Er:YAG SP preparations compared to Er:YAG QSP. [ABSTRACT FROM AUTHOR]

Melasma is a chronic relapsing skin condition. Laser therapy is a new advancement in treatment. Whether the topical application of tranexamic acid (TXA) increases the efficacy of laser therapy in melasma is still under debate. With recent studies yielding different results, it was imperative to compile all the available literature systematically. This meta-analysis investigates the effectiveness of a combination therapy of laser plus TXA acid for treating melasma. PubMed/MEDLINE, Cochrane Central, Google Scholar, Scopus, and the International Clinical Trials registry were systematically searched for article retrieval. Screening per PRISMA guidelines was undertaken by two independent reviewers using the Covidance database. Melasma area of severity index (MASI)/modified MASI was used as the clinical improvement outcomes. A total of nine studies that described the combined use of topical tranexamic acid with laser therapy were included for meta-analysis. These studies employed various types of lasers along with topical TXA. The results showed that the combination of both laser therapy and topical TXA significantly decreased the MASI score (P < 0.0001). Subgroup analyses revealed that fractional CO2 laser among the laser types and monthly laser plus twice daily topical TXA were most effective in decreasing the MASI/mMASI score. The meta-analysis found that combining topical tranexamic acid and laser therapy is an effective and safer treatment option for treatment-resistant melasma. Furthermore, monthly fractional CO2 laser and daily application of topical tranexamic acid showed high effectiveness and safety. [ABSTRACT FROM AUTHOR]

The aim of this study is to evaluate changes in vaginal pH and epithelium maturation after erbium-doped yttrium aluminum garnet (Er-YAG) laser treatment, and to assess its safety and efficacy on the symptoms of genitourinary syndrome of menopause (GSM). This was a retrospective study conducted between November 2019 and April 2022 and included 32 women diagnosed with GSM who had not benefitted from lubrication treatment and could not or would not use estrogen. Patients received three sessions of Er- YAG laser. All patient data before and after treatment were obtained from computer records. Vaginal maturation index (VMI), maturation value (MV) and vaginal pH values of the patients before and after laser treatment were compared. We also evaluated post-procedural complications and symptoms. Mean age was 59.72 ± 5.66 years. After laser therapy, there was a significant decrease in vaginal pH (p < 0.001) and the proportion of parabasal cells in VMI (p < 0.001), while there was a significant increase in MV (p < 0.001) and the proportion of superficial cells in VMI (p < 0.001). In 84.4% of the patients, GSM-related symptoms regressed completely or decreased to a tolerable level. Patients in which symptoms disappeared completely had significantly lower mean age (p = 0.002) and duration of menopause (p = 0.009). The laser procedure resulted in complications including mucosal injury in 5 (15.6%) patients (all recovered spontaneously) and vaginal burning sensation in 2 (6.3%) patients. Vaginal Er-YAG laser treatment may be a safe and effective alternative treatment method in a population of women with GSM who do not want to or cannot use estrogen therapy. [ABSTRACT FROM AUTHOR]

This investigation has aimed to compare the efficiency of clinical depigmentation and repigmentation rate of erbium chromium–doped: yttrium, scandium, gallium, garnet (Er,Cr:YSGG) and diode lasers during a 1-year follow-up and to evaluate patient satisfaction. Twenty-two participants were divided into Er,Cr:YSGG laser and diode laser groups using computer-aided randomization. Dummett Oral Pigmentation Index (DOPI) and photographic assessment with ImageJ Software version 10.2 were performed at the preoperative period and postoperative 1st month, 6th month, and 12th month. Moreover, the study assessed intra- and postoperative intensities of pain and postoperative patient aesthetic satisfaction using the Visual Analog Scale in both groups. The median values of DOPI did not differ statistically between the groups according to time (p > 0.05). In the Er,Cr:YSGG group, the extension of repigmentation was less as compared to the diode group at 1-year follow-up (p = 0.045). In the Er,Cr:YSGG group, the patients felt less intraoperative pain and discomfort compared to the diode group (p = 0.007). No significant differences were found between the two groups in terms of patient aesthetic satisfaction at the 1st and 12th months. The findings indicate that diode and Er,Cr:YSGG lasers can be used safely in depigmentation treatment, while the Er,Cr:YSGG laser has been shown to have superiorities in pain management and patient comfort parameters. Clinical Trial No.: NCT05304624. [ABSTRACT FROM AUTHOR]

It was to report a rare case of peripheral odontogenic myxoma removed with high-power diode laser and to do an extensive review of studies of odontogenic cysts and tumors treated with high-power laser (HPL). This is a rare case of a 63-year-old male patient with a peripheral odontogenic myxoma measuring approximately 10 cm in the attached gingiva region of tooth 16 removed with a high-power diode laser (808 nm, 3 W, in continuous mode, under constant suction, with 400-µm optical fiber). A literature review was also carried out looking for articles that involved the use of HPL in the treatment of odontogenic cysts and tumors, without restriction of year or language. In the present case, there was no need for suturing, no postoperative discomfort, and minimal bleeding during the procedure. In a 12-month follow-up period, there were no signs of recurrence. Only two cases of intra-osseous odontogenic myxomas treated with HPL and 10 cases involving other odontogenic cysts and tumors were found. All studies showing HPL to be effective in treating these lesions. Despite the different types of lasers used and different parameters, it is observed that lasers are effective in the treatment of odontogenic lesions. [ABSTRACT FROM AUTHOR]

Optically tunable gold nanoparticles have been widely used in research with near-infrared light as a means to enhance laser-induced thermal therapy since it capitalizes on nanoparticles' plasmonic heating properties. There have been several studies published on numerical models replicating this therapy in such conditions. However, there are several limitations on some of the models which can render the model unfaithful to therapy simulations. In this paper, two techniques of simulating laser-induced thermal therapy with a high-absorbing localized region of interest inside a phantom are compared. To validate these models, we conducted an experiment of an agar-agar phantom with an inclusion reproducing it with both models. The phantom was optically characterized by absorption and total attenuation. The first model is based on the macroperspective solution of the radiative transfer equation given by the diffusion equation, which is then coupled with the Pennes bioheat equation to obtain the temperature. The second is a Monte Carlo model that considers a stochastic solution of the same equation and is also considered as input to the Pennes bioheat transfer equation which is then computed. The Monte Carlo is in good agreement with the experimental data having an average percentage difference of 4.5% and a correlation factor of 0.98, while the diffusion method comparison with experimental data is 61% and 0.95 respectively. The optical characterization of the phantom and its inclusion were also validated indirectly since the Monte Carlo, which used those parameters, was also validated. While knowing the temperature in all points inside a body during photothermal therapy is important, one has to be mindful of the model which fits the conditions and properties. There are several reasons to justify the discrepancy of the diffusion method: low-scattering conditions, absorption, and reduced scattering are comparable. The error bars that are normally associated when characterizing an optical phantom can justify also a part of that uncertainty. For low-size tumors in depth, one may have to increase the light dosage in photothermal therapies to have a more effective treatment. [ABSTRACT FROM AUTHOR]

In recent years, there has been increasing interest in research showing positive results in antimicrobial photodynamic therapy (aPDT) and laser therapy (LT) in dentistry. The authors of this review tried to answer the question: "Is the effectiveness of lasers and aPDT in the elimination of intraoral halitosis possible?" For this purpose, the electronic database of PubMed and Cochrane Library were searched until September 2021 using a combination of different keywords: (bad breath OR fetor ex ore OR halitosis OR oral malodor) AND (laser OR PDT OR PACT OR photodynamic inactivation OR photodynamic therapy OR photodynamic antimicrobial chemotherapy). Initially, 83 studies were identified. A total of 9 articles were qualified after the application of the eligibility criteria. Eight works concerned aPDT treatment, and only one dedicated to the Er,Cr:YSGG laser. A significant reduction in halitosis occurred immediately after both LT and aPDT. The review found the confirmation of the effectiveness of laser therapy in reducing the number of volatile sulfur compounds (VSC) and the amount of anaerobic bacteria responsible for VSC formation. In most studies, a positive effect was observed for a 1-week follow-up. Laser therapy (aPDT, Er,Cr:YSGG) effectively eliminates microorganisms that produce volatile compounds and can effectively eliminate bad breath for the longer period of time than traditional methods of combatting this ailment. [ABSTRACT FROM AUTHOR]

Selective photothermolysis of the sebaceous glands has the potential to be an effective alternative for treating acne vulgaris. However, the translation of this technique to clinical settings has been hindered by a lack of appropriate energy sources to target sebaceous glands, concerns surrounding safety, and treatment-related discomfort and downtime. In this work, we introduce the first FDA-approved system that combines a 1726-nm laser and efficient contact cooling to treat mild, moderate, and severe acne effectively while ensuring safety and minimal patient discomfort without adjunct pain mitigation techniques. Light transport and bioheat transfer simulations were performed to demonstrate the system's efficacy and selectivity. The resulting thermal damage to the skin and sebaceous glands was modeled using the Arrhenius kinetic model. Numerical simulations demonstrated that combining laser energy and optimal contact cooling could induce a significant temperature increase spatially limited to the sebaceous gland; this results in highly selective targeting and maximum damage to the sebaceous gland while preserving other skin structures. In vivo human facial skin histology results corroborated the simulation results. The studies reported here demonstrate that the presented 1726-nm laser system induces selective photothermolysis of the sebaceous gland, providing a safe and effective method for the treatment of acne vulgaris. [ABSTRACT FROM AUTHOR]

This systematic review aimed to answer the research focused question: What are the effects of photobiomodulation (PBM) therapy on bone healing after ionizing irradiation in animal models? The EMBASE, LILACS, LIVIVO, PubMed, Scopus, and Web of Science databases, including gray literature, were searched using the following keywords: "Head and Neck Neoplasms"; "Ionizing Radiation"; "Low-Level Light Therapy"; and "Bone regeneration", focusing on the primary studies that assessed the effects of PBM therapy on animal models of irradiated bone. Six studies have met the eligibility criteria and presented an overall regular quality according to the risk of bias assessment tools. All the studies utilized rat animal model and near-infrared laser PBM at low power output setting. Most of the studies showed increased new bone formation, osteocytes, osteoblasts, and vascularization networking, as a result of PBM therapy. However, only one out of the six studies has not shown any differences in bone healing in both lased and non-lased animal groups. Nevertheless, PBM therapy is a potential tool to improve bone healing induced by ionizing radiation. However, due to the scarce number of studies and the great variability of laser parameters and treatment protocols, a clear conclusion cannot be drawn. Hence, extensive preclinical in vivo studies are warranted to ensure these beneficial effects have been addressed prior to translational clinical trials. [ABSTRACT FROM AUTHOR]

Scarring is one of the most esthetically challenging and psychologically burdening aspects following inflammatory acne. While "macular" disease is the scar subtype with the least complicated outcome, its phase can be regarded as the most defining in the ultimate scar appearance. Moreover, with lasers recently gaining much popularity in the scientific community for managing several dermatologic conditions, we aimed to evaluate whether they would lead to significant benefits. For this systematic review, four databases consisting of PubMed, Scopus, Embase, and Web of Science were searched using a comprehensive string, with the data from the relevant yet eligible identified records qualitatively synthesized. After investigating the data obtained from the nine included studies, we found the utilized lasers, namely neodymium-doped yttrium aluminum garnet, fractional carbon dioxide, pulsed dye, erbium:glass, pro-yellow, and high-power optically pumped semiconductor, to be highly effective in managing the erythematous or dyspigmented appearance with the reduced elasticity also significantly improving. Moreover, the adverse events were both bearable and minimal, and transient. However, the degree of improvement each type of scar demonstrated following laser therapy varied based on the laser used. Neodymium-doped yttrium aluminum garnet, fractional carbon dioxide, and pulsed dye are the most commonly investigated lasers for managing macular acne scars, demonstrating eye-catching capabilities in managing either erythema or dyspigmentation. However, we still recommend that further comparative interventional studies be carried out, while the intended outcomes also assessed with objective measures for further clarification. [ABSTRACT FROM AUTHOR]

This study aimed to compare the effects of (HNLT) and (ILT) on diabetic foot ulcer. Sixty-five patients with diabetic foot ulcer (51 males and 14 females) aged 50-60 years. The participants were classified randomly to two groups, groups I and II. Group I received helium-neon laser therapy (HNLT) and conventional therapy with and group II received infrared laser therapy (ILT) and conventional therapy with for 8 weeks. Ulcer surface area was assessed using a sheet of cellophane paper at the beginning of the study, after 4 weeks, and after 8 weeks at the end of the study. At the beginning of the study, baseline clinical characteristics showed non-significant differences between the two groups (p > 0.05). After 4 weeks intervention, there were significant improvements in ulcer surface area in the two groups (p < 0.05). At the end of the study, after 8 weeks intervention, there were higher reduction in ulcer area in HNLT group more than ILT group, but this difference was statistically non- significant between the two groups (p > 0.05). The present study demonstrates that HNLT and ILT have similar effects to control diabetic foot ulcer in a short-term (up to 8 weeks). Eight weeks of laser therapy have beneficial impacts in diabetic foot ulcer. [ABSTRACT FROM AUTHOR]

Infrared neural stimulation (INS) is a new and developing approach for neural repair, with the advantages of being non-contact, spatially precise, and artifact-free. However, the disadvantage of infrared light is that it is difficult to stimulate deep tissue because of its weak penetrating power. Therefore, this paper introduces an improved method using near-infrared laser to stimulate bullfrog sciatic nerves because of its strong penetrating power. Meanwhile, gold nanorods (Au NRs) are injected into the nerve to increase the absorption of light. The mechanism is the instantaneous temperature rise caused by the absorption of infrared light by Au NRs. The compound muscle action potential (CMAP) associated with the irradiated sciatic nerve is recorded by a multi-channel physiological signal instrument. The peak to peak amplitude (Vpp) of CMAP for sciatic nerves injected with Au NRs increases significantly compared to the CMAP for control nerves without Au NRs. These results demonstrate INS by labeling nerves with nanoparticle exhibiting latent capacity to increase the efficiency, spatial resolution, and the neural responsivity, and especially, can increase the penetration depth and reduce the requisite radiant exposure level. [ABSTRACT FROM AUTHOR]

Keywords: Public Health; Quantum Electronics; Nonlinear Optic; Hard Tissue; Ablation Efficacy EN Public Health Quantum Electronics Nonlinear Optic Hard Tissue Ablation Efficacy 1 1 1 12/09/22 20221202 NES 221202 This article was retracted by the Editors, as the paper was originally published by Mersini I Makropoulou and Eirini I Papagiakoumou (2004) Lasers and hard-tissue interactions. Public Health, Quantum Electronics, Nonlinear Optic, Ablation Efficacy, Hard Tissue. [Extracted from the article]

Purpose: Several treatment options are proposed for the management of pelvic floor myofascial pain (PFMP). Manual therapy, such as vaginal stretching (VS), is one of these options. Photobiomodulation therapy (PBMT) with a laser device is a treatment option for PFMP that has been tested on other muscles. The aim of this study was to evaluate the effect of VS combined or not with PBMT for PFMP treatment. Methods: One hundred three women with PFMP were enrolled in a double-blind randomized trial and assigned to VS+PBMT (10 treatments over 2 weeks with 100 mw delivering 12 joules to surface intravaginally, using near-infrared light 808 nm) and VS+shamPBMT treatment groups. Pain severity was assessed by Visual Analog Scale (VAS). Pelvic floor muscle function was assessed by Oxford Scale and surface electromyography. Urinary symptoms were evaluated by ICIQ-OAB and ICIQ-SF questionnaires, and intestinal constipation was assessed by ROMA criteria. Results: There was a significant improvement in pain intensity (VAS) after treatment in both groups, with no difference between groups (p = 0.46). More than 50% of the women complained of severe pain before treatment, and after treatments, it was reported by less than 20% of women (p < 0.001), with no difference between groups (p = 0.08). Urinary symptoms improved in both groups (p < 0.001) with no difference between groups (p = 0.37). Intestinal constipation improved in the VS+PBMT group only (p = 0.01). Conclusion: VS and VS with near-infrared vaginal laser therapy were equally effective at decreasing myofascial pelvic pain and reducing urinary symptoms Trial registration: REBEC (Registro Brasileiro de Ensaios Clínicos; Brazilian Registry of Clinical Trials) under no.RBR-2TDCQ4 (November 11, 2018) [ABSTRACT FROM AUTHOR]

Laser-induced breakdown spectroscopy (LIBS) is an emerging analytical technique with numerous advantages such as rapidity, multi-elemental analysis, no specific sample preparation requirements, non-destructiveness, and versatility. It has been proven to be a robust elemental analysis tool attracting interest because of being applied to a wide range of materials including biomaterials. In this paper, we have performed spectroscopic studies on gallstones which are heterogeneous in nature using LIBS and wavelength dispersive X-ray fluorescence (WD-XRF) techniques. It has been observed that the presence and relative concentrations of trace elements in different kind of gallstones (cholesterol and pigment gallstones) can easily be determined using LIBS technique. From the experiments carried out on gallstones for trace elemental mapping and detection, it was found that LIBS is a robust tool for such biomedical applications. The stone samples studied in the present paper were classified using the Fourier transform infrared (FTIR) spectroscopy. WD-XRF spectroscopy has been applied for the qualitative and quantitative analysis of major and trace elements present in the gallstone which was compared with the LIBS data. The results obtained in the present paper show interesting prospects for LIBS and WD-XRF to study cholelithiasis better. [ABSTRACT FROM AUTHOR]

There are many laser technologies that are being tested that claim to support hair regrowth for patients with alopecia areata (AA). In this paper, we will determine whether the body of evidence supports the use of devices using monochromatic light sources to treat AA. Articles were gathered from PubMed, Embase, and the Cochrane database using these keywords: lasers, excimer laser, low-level laser therapy (LLLT), low-level light therapy, alopecia, alopecia areata, and hair loss with a category modifier of English. Ten clinical trials and seven case reports/abstracts were assessed. Eight clinical trials and two case reports demonstrated hair regrowth with the 308-nm excimer laser/light in men, women, and children. One case report demonstrated hair regrowth with the ALBA 355® laser. One clinical trial and two case reports demonstrated hair regrowth with LLLT. While two case reports demonstrated hair regrowth with fractional laser therapy, one clinical trial showed no improvement. The 308-nm excimer laser is a safe and effective treatment for men, women, and children with refractory AA of the scalp and beard. Larger, double-blinded clinical trials should be conducted to compare excimer laser therapy to standard treatments. More data is needed to determine the efficacy of LLLT and fractional laser therapy in the treatment of AA. [ABSTRACT FROM AUTHOR]

The aim of this work was to compare the fragmentation efficiency of a novel, pulsed Thulium solid-state laser (p-Tm:YAG) to that of a chopped Thulium fibre laser (TFL) and a pulsed Holmium solid-state laser (Ho:YAG). During the fragmentation process, we used a silicone mould to fixate the hemispherical stone models under water in a jar filled with room-temperature water. Each laser device registered the total energy applied to the stone model to determine fragmentation efficiency. Our study examined laser settings with single pulse energies ranging from 0.6 to 6 J and pulse frequencies ranging from 5 to 15 Hz. Similar laser settings were applied to explicitly compare the fragmentation efficiency of all three devices. We experimented with additional laser settings to see which of the three devices would perform best. The fragmentation performance of the three laser devices differed statistically significantly (p < 0.05). The average total energy required to fragment the stone model was 345.96 J for Ho:YAG, 372.43 J for p-Tm:YAG and 483.90 J for TFL. To fragment the stone models, both Ho:YAG and p-Tm:YAG needed similar total energy (p = 0.97). TFL's fragmentation efficiency is significantly lower than that of Ho:YAG and p-Tm:YAG. Furthermore, we found the novel p-Tm:YAG's fragmentation efficiency to closely resemble that of Ho:YAG. The fragmentation efficiency is thought to be influenced by the pulse duration. TFL's shortest possible pulse duration was considerably longer than that of Ho:YAG and p-Tm:YAG, resulting in Ho:YAG and p-Tm:YAG exhibiting better fragmenting efficiency. [ABSTRACT FROM AUTHOR]

Patients with recalcitrant facial port wine stains (rfPWS) can be challenging to manage, often leaving the clinician with difficult decisions for treatment options. 'Triple therapy' consists of using three different laser wavelengths at each treatment setting. The evidence on outcomes is limited as this treatment approach has not been previously reported to the best of our knowledge. Children who received triple therapy at least once for rfPWS, and for whom SIAscopy readings had been taken, were retrospectively identified. SIAscope readings were compared before the first triple therapy treatment and at final the most recent clinical follow-up. The clinical appearance was also assessed using a Visual Analogue Scale comparing clinical photographs taken before triple therapy to those taken at the most recent clinical follow-up. A total of 47 children were identified and included in our review. The SIAscope readings showed an overall significant (p < 0.001) lightening with 39 (83%) showing lightening and 8 (17%) patients showing a darkening. Scores using the VAS also showed improvement with 55% experiencing an improvement in their clinical appearance, 38% showing no visible change and 6% appearing to have worsened. Triple therapy can offer improvement of rfPWS which have failed to respond to single wavelength laser therapy. SIAscopy and VAS scores correlate well in assessing clinical response; however, the added clinical benefit of SIAscopy in vascular laser clinics remains uncertain. [ABSTRACT FROM AUTHOR]

The 755-nm Alexandrite Laser has a good clinical effect in treating resistant port wine stain, without causing thermal damage of normal tissue and side effects such as purpura. However, little is known about the mechanism of vascular damage induced by 755-nm laser irradiation, which restricts the optimization of laser parameters. In this work, the thermal damage model and the pressure damage model were used to study the damage mechanism of 755-nm laser irradiation on vessels, and the incident energy density and pulse width required for vascular damage were determined according to the damage mode. Under the irradiation of 755-nm laser, the vascular injury pattern was the co-occurrence of vessel rupture and vessel constriction, and the energy density required for the treatment of vessels with a diameter of 200 μm to reach the damage threshold was the lowest. [ABSTRACT FROM AUTHOR]

To explore the long-term intraocular pressure (IOP)-lowering effect of monocular selective laser trabeculoplasty (SLT) in the untreated fellow eyes of open-angle glaucoma (OAG) patients. This was a retrospective observational study. Consecutive Chinese OAG patients who received monocular SLT treatment were included in this study. One hundred and eighty degree SLT was conducted as adjunctive treatment when anti-glaucoma medication was not sufficiently effective after clinical evaluation. Treatment success was defined as more than 20% IOP reduction of the baseline IOP levels. IOP-decreasing amplitude and SLT success rate of both eyes were investigated during the 3-year follow-up period. Age, gender, baseline IOP levels, number of medications, and SLT energy parameters were analyzed to determine its influence on IOP reduction effect and treatment success rate. A total of 32 Chinese OAG patients were included in this study and 25 of them completed the 3-year follow-ups. Their pretreatment IOPs were 18.85 ± 2.81 mmHg in the treated eyes and 17.38 ± 2.37 mmHg in the fellow eyes. At the 3-year follow-up visits, IOP decreased to 2.76 ± 3.72 mmHg (14.16%) in the treated eyes and 2.16 ± 2.73 mmHg (11.95%) in the fellow eyes, with a success rate of 47.83% (11 in 23 cases) and 44.00% (11 in 25 cases), respectively. IOPs of both eyes decreased significantly after SLT from 6 months and lasted to 3 years after treatment. Baseline IOP level was positively correlated with IOP reduction in the treated eyes and other factors were not correlated with IOP reduction and treatment success. Monocular SLT treatment as adjunctive treatment could lower IOPs not only in the treated eyes but also in the untreated eyes in poor medication-controlled OAG patients. In addition, its IOP reduction effect could last to 3 years after treatment in clinical practice. [ABSTRACT FROM AUTHOR]

Inadvertent Er:YAG laser irradiation occurs in dentistry and may harm restorative materials in teeth. The aim of this in vitro study was to quantify Er:YAG laser-induced damage to a nanohybrid composite in simulated clinical scenarios for inadvertent direct and indirect (reflection) laser irradiation. The simulation was performed by varying the output energy (OE;direct˃indirect) reaching the specimen and the operating distance (OD;direct˂indirect). Composite specimens were irradiated by an Er:YAG laser. The ablation threshold was determined and clinically relevant parameters were applied (n = 6 for each OE/OD combination) for direct (OE: 570 mJ/OD: 10 mm, OE: 190 mJ/OD: 10 mm) and indirect irradiation (OE: 466 mJ/OD: 15 mm, OE: 57 mJ/OD: 15 mm, OE: 155 mJ/OD: 15 mm, OE: 19 mJ/OD: 15 mm). The extent of damage in the form of craters was evaluated using a laser scanning microscope (LSM) and a conventional light microscope (LM). The ablation threshold was determined to be 2.6 J/cm2. The crater diameter showed the highest value (LM: 1075 ± 18 µm/LSM: 1082 ± 17 µm) for indirect irradiation (reflectant:dental mirror) (OE: 466 mJ/OD: 15 mm). The crater depth showed the highest and comparable value for direct (OE: 570 mJ/OD: 10 mm; LSM: 89 ± 2 µm) and indirect irradiation (OE: 466 mJ/OD: 15 mm; LSM: 90 ± 4 µm). For each OD, the crater diameter, depth, and volume increased with higher laser fluence. However, the OD-and thus the laser spot diameter-also had an enlarging effect. Thus, indirect irradiation (reflectant:dental mirror) with only 47% of the laser fluence of direct irradiation led to a larger diameter and a comparable depth. The three-dimensional extent of the crater was large enough to cause roughening, which may lead to plaque accumulation and encourage caries, gingivitis, and periodontitis under clinical conditions. Clinicians should be aware that reflected irradiation can still create such craters. [ABSTRACT FROM AUTHOR]

The aim of this work was to perform an integrative literature review on the influence of laser irradiation on zirconia implants to enhance surface topographic aspects and the biological response for osseointegration. An electronic search was carried out on the PubMed database using the following search terms: "zirconia" AND "laser" AND "surface modification" OR "surface treatment" AND "dental implants" OR "bone" OR "osteoblast" OR "osseointegration." Of the identified articles, 12 studies were selected in this review. Results reported that the laser irradiation was capable of promoting changes on the zirconia surfaces regarding topographic aspects, roughness, and wettability. An increase in roughness was recorded at micro- and nano-scale and it resulted in an enhanced wettability and biological response. Also, adhesion, spreading, proliferation, and differentiation of osteogenic cells were also enhanced after laser irradiation mainly by using a femtosecond laser at 10nJ and 80 MHz. After 3 months of osseointegration, in vivo studies in dogs revealed a similar average percentage of bone-to-implant contact (BIC) on zirconia surfaces (around 47.9 ± 16%) when compared to standard titanium surfaces (61.73 ±16.27%), denoting that there is no significant difference between such different materials. The laser approach revealed several parameters that can be used for zirconia surface modification such as irradiation intensity, time, and frequency. Laser irradiation parameters can be optimized and well-controlled to reach desirable surface morphologic aspects and biological response concerning the osseointegration process. [ABSTRACT FROM AUTHOR]

The literature on the efficacy of erbium lasers for nonsurgical periodontal therapy is inconsistent. The objective of the umbrella review was to collate the information available in the systematic reviews to provide a comprehensive synthesis of clinical and patient reported outcomes following the use of erbium lasers for non-surgical periodontal therapy. An electronic database search was carried out, and systematic reviews/meta-analyses which assessed the efficacy of erbium lasers as monotherapy or as an adjunct to scaling and root planing were included. The methodological quality and reporting quality of the included studies were assessed. 15 Systematic reviews/meta-analyses were obtained after title, abstract, and full text search. The meta-analyses data revealed a clinical attachment level gain, reduction in probing pocket depth at 1 and 3-month follow-up, and no additional benefit at ≥ 6-month follow-up in the erbium laser group. The evidence gap map revealed lack of clinical outcome data at > 6-month follow-up and dearth in studies assessing patient reported outcome measures and adverse events. Erbium lasers may provide short-term clinical benefits, and further studies with standardized laser parameters evaluating long-term follow-up, patient-reported outcome measures, and adverse events are needed. [ABSTRACT FROM AUTHOR]

Photobiomodulation therapy (PBMT) is an effective means of treating muscle spasm and pain. A novel near-infrared laser system has been commercialized for the treatment of myofascial pelvic pain in women (SoLá Therapy, UroShape, LLC). This study was undertaken to determine if this device is capable of delivering therapeutic levels of irradiance to the pelvic muscles and to identify the surface irradiance required to achieve this goal. This novel class IV near-infrared laser and transvaginal applicator were used to deliver near-infrared light energy through the vaginal mucosa of an adult Suffolk/Dorset Ewe. Irradiance was measured on the surface of the levator ani muscle, inside the levator ani muscle, and inside the bladder. Measurements were taken at powers of 5 W and 0.5 W. 3.0% of vaginal surface irradiance was measured inside of the levator ani muscle. 4.4% of vaginal surface irradiance was measured inside the bladder. At 5 W, the novel laser system provided a surface irradiance of 738 mW/cm2. At 0.5 W, the system provided a surface irradiance of 74 mW/cm2. A novel class IV near-infrared laser and transvaginal applicator delivered therapeutic irradiance to the levator ani muscle and bladder of an anesthetized ewe at a power setting of 5 W. A power setting of 0.5 W failed to deliver therapeutic energy into either the levator ani muscle or bladder. Clinical applications targeting deeper tissues such as the pelvic muscles and or bladder should consider power settings that exceed 0.5 W and or irradiance of ≥ 75 mW/cm2. [ABSTRACT FROM AUTHOR]

Surgical treatment is standard for the treatment of small breast cancers. Due to the pain and esthetic sequelae that can follow surgery, minimally invasive treatments are under investigation. Our aim was to conduct a dosimetry study of laser interstitial thermotherapy. Turkey tissue was used as an ex vivo model, and mammary glands from ewes were used as in vivo models. We used two different wavelength lasers (805 nm and 980 nm). Two types of fiber from two different manufacturers were used: bare fibers with a diameter of 600 μm and diffusing fiber. The diffusing fibers were 5 mm and 10 mm in length. We also used a computerized model to predict thermal damage and to correlate with the ex vivo and in vivo procedures using a constant and variable coefficient. The mathematical model was based on the finite element method for solving light distribution, bio-heat, and thermal damage equations. Based on our ex vivo and in vivo experiments, we found that the optimal configuration for this treatment was the use of the 980-nm laser at 4 W with bare fibers for a minimum treatment time of 150 s. We also developed a predictive mathematical model that showed good predictability of necrosis in line with the experimental data. Laser treatment is a promising therapy for small breast lesions. However, further development of treatment guidance is necessary to support its use in clinical practice. [ABSTRACT FROM AUTHOR]

The objective of this article is to study the clinical efficacy and adverse events of laser-assisted drug delivery in the treatment of hypertrophic and keloid scars. We searched the following databases up to 22 October 2020: the Cochrane Skin Group Specialised Register, the Cochrane Central Register of Controlled Trials (Clinical Trials) in The Cochrane Library, MEDLINE, EMBASE, and reference lists of articles for randomised clinical trials (RCTs) of laser-assisted drug delivery for the treatment of hypertrophic and keloid scars. We also searched online trials registries for ongoing trials and contacted trial authors where appropriate. Our outcomes of interest were objective clinical evaluation of scars, participant satisfaction, and adverse effects of the treatments. Two authors independently extracted data and assessed trial quality using Cochrane Risk of Bias 2. Two authors independently abstracted data. We included 10 RCTs involving a total of 329 participants: six trials utilised parallel-arm RCTs whilst four employed split-scar design. Three trials had high risk of bias with the remaining seven rated as having some concerns. The interventions and outcomes were too varied to be combined statistically. High-quality randomised controlled trials assessing laser-assisted delivery for drugs in the context of hypertrophic and/or keloid scarring are needed. Studies with a larger number of participants, with longer follow-up times, and standardised evaluation of outcome and adverse effects are warranted. [ABSTRACT FROM AUTHOR]

There are inconclusive results regarding etching and bonding protocol to achieve optimal bond strength and marginal integrity of adhesive composite resin restorations in erbium laser prepared cavities. This systematic review aimed to consider which adhesive system protocol may be optimal in achieving the bond strength and marginal integrity in erbium laser–prepared cavities, comparable to that obtained with conventional method of cavity preparation. This review was developed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement with literature search based on all publications during the period January1, 2000–October 10, 2020, in three databases: MEDLINE, Google Scholar and ScienceDirect. The necessary information was extracted by two independent authors. The search resulted in 139 articles from all databases, and a total of thirty-one articles met the inclusion criteria. The results indicated that the selection of adhesives depending on their pH and composition and the laser pulse duration and pulse energy used plays an important role in predicting the adhesion and marginal integrity. The 10-MDP containing moderate self-etch adhesives has demonstrated predictable outcomes. Longer pulse durations used for cavity preparations may indicate the use of etch-and-rinse (EnR) or moderate self-etch adhesives (SEA) to allow better resin infiltration in deep craters formed due to laser irradiation. However, further studies with more standardizations in relation to adhesives and laser parameters are needed. [ABSTRACT FROM AUTHOR]

We aimed to analyze the results of 5-year consecutive use of the hemorrhoidal laser procedure (HeLP) in patients with second- to third-grade hemorrhoids with minimal or moderate mucosal prolapse. A total of 189 patients were treated between April 2012 and October 2017. We reported perioperative complications, postoperative pain, improvement of hemorrhoids grade, and relapse of hemorrhoidal disease (HD). Improvement of symptoms was assessed using the Patient Global Improvement (PGI) Scale. No severe intraoperative complications were observed. The median follow-up was 42 months (range 6–62 months). Pain after surgery was absent in 94% of patients. No cases of rectal tenesmus or alterations of defecation habits were reported. Symptoms and HD improvement reached a "plateau" at 3 to 6 months following surgery. We observed a significant decrease in HD degree, occurrence of bleeding, pain, itching, and acute HD. Complete resolution of HD was reported in > 60% of patients 1 year after surgery. The individual level of improvement in symptoms was consistent (very much and much improved, according to PGI-I score) for about 90% of patients during the follow-up. This study confirmed that the HeLP is a safe, painless, and effective procedure for the treatment of HD in selected cases. [ABSTRACT FROM AUTHOR]

Incorporeal lithotripsy by using holmium:YAG laser has been recently successfully spread and used in the treatment of urolithiasis. Although this method is not as common in salivary gland surgery, it is also recommended for endoscopic treatment of sialolithiasis. In this study, we decided to analyse effectiveness of holmium:YAG laser method among patients with midsize stones as the treatment in this particular population is still not determined and remains in dispute. Thus, the primary aim of the study is a prospective, complex analysis of incorporeal holmium:YAG laser lithotripsy effectiveness and safety in patients suffering from sialolithiasis. The examined group consisted of 32 consecutive patients, 17 female (53%) and 15 male (47%). The average age was 42 (age range 22–70). In our series, sialoendoscopy with intraductal lithotripsy was performed in patients with wide range of stone's diameter (3 to 10 mm). The calculi were removed with foreign body forceps or retrieval basket, after stone fragmentation with holmium:YAG laser. The power of the laser during surgery was set at 2.5 to 3.5 W. One shot energy equalled 0.5–0.7 J with frequency of 5 Hz. The bivariate Pearson Correlation and a point-biserial correlation were used to analyse the data. Total success rate of holmium:YAG laser lithotripsy in this consecutive group was equal to 90% and efficacy in the group with excluded cases when endoscopic approach difficulties were experienced (stone not visible) reached 93%. The long-term follow-up revealed that in 26 patients (84%), complete recovery was achieved. Two patients developed Wharton's duct stenosis and one Stensen's duct orifice stenosis (9.5%), of whom one required reoperation. Two patients eventually underwent total excision of submandibular gland. Sialoendoscopy combined with incorporeal laser-assisted lithotripsy proved to be effective and safe method for treatment of sialothiasis with midsize stones (4–8 mm) in population of clinic. Even taking into account the prevalence of complications associated with holmium:YAG laser, it is still safer alternative compared to open surgery where there is a significant risk of the bleeding, wound infection or injury of the facial nerve. [ABSTRACT FROM AUTHOR]

The goal of this study was to assess the ablation, coagulation, and carbonization characteristics of the holmium:YAG (Ho:YAG) laser and thulium fiber lasers (TFL). The Ho:YAG laser (100 W av.power), the quasi-continuous (QCW) TFL (120 W av.power), and the SuperPulsed (SP) TFL (50 W av.power) were compared on a non-frozen porcine kidney. To control the cutting speed (2 or 5 mm/s), an XY translation stage was used. The Ho:YAG was tested using E = 1.5 J and Pav = 40 W or Pav = 70 W settings. The TFL was tested using E = 1.5 J and Pav = 30 W or Pav = 60 W settings. After ex vivo incision, histological analysis was performed in order to estimate thermal damage. At 40 W, the Ho:YAG displayed a shallower cutting at 2 and 5 mm/s (1.1 ± 0.2 mm and 0.5 ± 0.2 mm, respectively) with virtually zero coagulation. While at 70 W, the minimal coagulation depth measured 0.1 ± 0.1 mm. The incisions demonstrated zero carbonization. Both the QCW and SP TFL did show effective cutting at all speeds (2.1 ± 0.2 mm and 1.3 ± 0.2 mm, respectively, at 30 W) with prominent coagulation (0.6 ± 0.1 mm and 0.4 ± 0.1 mm, respectively, at 70 W) and carbonization. Our study introduced the TFL as a novel efficient alternative for soft tissue surgery to the Ho:YAG laser. The SP TFL offers a Ho:YAG-like incision, while QCW TFL allows for fast, deep, and precise cutting with increased carbonization. [ABSTRACT FROM AUTHOR]

In the last decades, new technological devices and instruments have been developed to overcome the technical limits of transoral laser microsurgery. The recent introduction of 3D endoscopy seems to be a promising tool in the field of diagnostic and operative laryngology as an alternative to the traditional microlaryngoscopy. Our work aims to present a novel transoral microsurgical setting that expands the use of exoscopic systems (in this case the VITOM® 3D-HD) as an alternative to the standard operating microscope. A customized support arm and an adaptor to firmly connect the VITOM® 3D-HD camera to the laser micromanipulator were specially designed. This setup was used as an alternative to the standard operating microscope in a cohort of 17 patients affected by suspicious early to intermediate pharyngo-laryngeal neoplasms. A historical cohort of patients treated with the traditional setting and matching the same inclusion criteria was used as a reference for the duration of surgical procedures. The surgical procedures comprised 7 cordectomies, 2 endoscopic partial supraglottic laryngectomies, 4 tongue base resections, and 4 lateral oropharyngectomies or hypopharyngectomies. In 6 cases (35%), a simultaneous neck dissection was performed. The low rate of positive deep (6%) or superficial (12%) margins reinforced the safety of this platform, and the results obtained in terms of operating time were comparable to the control group (p > 0.05), which confirms the feasibility of the system. Our surgical setting setup is a convincing alternative to traditional transoral laser microsurgery for early to intermediate pharyngo-laryngeal neoplasms. The main advantages of this system are comfortable ergonomics for the first surgeon and a potential benefit in terms of teaching if applied in university hospitals, since the entire surgical team can view the same surgical 3D-HD view of the first operator. Further work is still needed to objectively compare the traditional and new technique, and to validate our preliminary clinical findings. [ABSTRACT FROM AUTHOR]

This paper implemented a model study of combined electrical and near-infrared (808 nm) neural stimulation (NINS) on the bullfrog sciatic nerve. The model includes a COMSOL model to calculate the electric-field distribution of the surrounding area of the nerve, a Monte Carlo model to simulate light transport and absorption in the bullfrog sciatic nerve during NINS, and a NEURON model to simulate the neural electrophysiology changes under electrical stimulus and laser irradiation. The optical thermal effect is considered the main mechanism during NINS. Therefore, thermal change during laser irradiation was calculated by the Monte Carlo method, and the temperature distribution was then transferred to the NEURON model to stimulate the sciatic nerve. The effects on thermal response by adjusting the laser spot size, energy of the beam, and the absorption coefficient of the nerve are analyzed. The effect of the ambient temperature on the electrical stimulation or laser stimulation and the interaction between laser irradiation and electrical stimulation are also studied. The results indicate that the needed stimulus threshold for neural activation or inhibition is reduced by laser irradiation. Additionally, the needed laser energy for blocking the action potential is reduced by electrical stimulus. Both electrical and laser stimulation are affected by the ambient temperature. These results provide references for subsequent animal experiments and could be of great help to future basic and applied studies of infrared neural stimulation (INS). [ABSTRACT FROM AUTHOR]

Publisher's Note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. The original article can be found online at https://doi.org/10.1007/s10103-023-03865-4. [Extracted from the article]

The photothermal effect is one of the most promising photonic procedures currently under development to successfully treat several clinical disorders, none the least some kinds of cancer. At present, this field is undergoing a renewed interest due to advances in both photothermal materials and better-suited light sources. However, scientific studies in this area are sometimes hampered by the relative unavailability of state-of-art materials or the complexity of setting up a dedicated optical facility. Here, we present a simple and affordable approach to do research in the photothermal field that relies on a commercial NIR laser pointer and a readily available everyday pigment: China ink. A proof-of-concept study is presented in which mice bearing intradermal LM3 mammary adenocarcinoma tumors were successfully treated in vivo employing China ink and the laser pointer. TUNEL and Ki-67 post-treatment tissue assessment clearly indicates the deleterious action of the photothermal treatment on the tumor. Therefore, the feasibility of this simple approach has been demonstrated, which may inspire other groups to implement simple procedures to further explore the photothermal effect. [ABSTRACT FROM AUTHOR]

This paper presents the results of endovenous laser ablation (EVLA) of varicose veins in vitro using radiation of a solid-state laser based on the crystal LiYF4:Tm, with a wavelength of 1.885 μm and power output of around 3 W. An experimental series with saline solution and red blood cell (RBC) suspension in the venous lumen was performed to identify the impact of a heated carbonized layer precipitated on the fiber end face versus the efficiency of EVLA. Results of these experiments confirmed that the presence of a heated carbonized layer on the fiber end face increases the efficiency of EVLA. [ABSTRACT FROM AUTHOR]

Low-intensity laser irradiation (LILI) can improve the deformability of red blood cells (RBCs). It might be due to the LILI effects on adenosine triphosphate (ATP) level. However, ATP content may not be a valid surrogate marker for RBC deformability. The LILI effects on RBC glycolysis were studied in this paper. Hypertonic RBCs were used in this study. After 5 min irradiation with low-intensity He-Ne laser irradiation (LHNL) at 632.8 nm and 4.4 mW/cm(2), the concentration of intracellular glucose and the activities of phosphofructokinase (PFK) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) were measured, respectively. There was no significant change in intracellular glucose concentration. The activity of PFK decreased significantly, but the activity of GAPDH increased significantly. In hypertonic RBCs, LHNL irradiation may decrease the activity of energy-consuming enzymes, but increases the activity of energy-generating enzymes in glycolysis, to improve the RBC deformability. [ABSTRACT FROM AUTHOR]

The aim of this study was comparing different lasers with conventional non-surgical treatment (CNT) for the management of peri-implantitis, regarding probing depth (PD), plaque index (PLI), clinical attachment level (CAL), and sulcus bleeding index (SBI). Randomized controlled trials (RCTs) on different lasers and CNT for peri-implantitis were searched. Pairwise and network meta-analyses were performed to analyze the PD, PLI, CAL, and SBI outcomes. The risk of bias, evidence quality, statistical heterogeneity, and ranking probability were also evaluated. Eleven studies were included in this study, involving three types of lasers. Diode + CNT had significantly superior efficacy to CNT alone, regarding PD reduction, while Er:YAG + CNT had significantly superior efficacy than CNT in terms of the PLI, CAL, and SBI. The highest probability of being most effective for PD was diode + CNT (49%), while Er:YAG + CNT had the highest probability of improving the PLI, CAL, and SBI (66%, 53%, and 79%, respectively). Diode + CNT was significantly superior for PD management in peri-implantitis compared with CNT alone, while Er:YAG + CNT significantly improved the PLI, CAL, and SBI. Therefore, Er:YAG + CNT might be recommended methods considered for management of peri-implantitis. [ABSTRACT FROM AUTHOR]

The purpose of this study was to investigate the shear bond strength (SBS) of ceramic discs luted to differently etched enamel and dentin surfaces. Occlusal surfaces of 64 carious-free human molars and vestibule surfaces of 64 first maxillary incisors were ground to get flat superficial dentin and flattened enamel respectively. After generating 4 groups according to the surface etching method (37% orthophosphoric acid, Er:YAG laser-contact handpiece/scanning handpiece (1 or 2 times of scanning)), ceramic discs were luted to the surfaces with adhesive resin cement (Variolink N, Vivadent Ets., Schaan/Liechtenstein). After etching and cementation, thermocycling of 5000 cycles (Sd Mechatronık Gmbh, Feldkirchen-Westerham, Germany) and SBS test (Servopulser EHFFD1; Shimadzu, Kyoto, Japan) were performed respectively. The surface morphologies of 2 specimens, etched enamel and dentin, prepared for each group were examined with SEM analysis. Failure modes were determined under a USB digital microscope. Data were analyzed with one-way analysis of variance (ANOVA) and Tukey HSD test (α = 0.05). SBS values in dentin surfaces showed statistically significant differences (p < 0.05) among tested groups. The highest SBS among dentin groups was determined in the group which had 2 times etching by Er:YAG laser (11.42 MPa) by a scanning handpiece. No statistical differences were observed in the other dentin or enamel groups. Laser etching seems to be a viable alternative to acid etching on both enamel and dentin surfaces while double etching of dentin with a scanning handpiece can improve the adhesion. [ABSTRACT FROM AUTHOR]