Lasers in Medical Science最新文献

To assess and compare the anti-microbial efficacy of 445 nm and 970 nm diode laser on mixed species biofilm of Aggregatibacter actinomycetemcomitans [A.a] and Porphyromonas gingivalis [P.g] cultured on machined pure titanium discs. A total of 65 machined pure titanium discs with no surface modifications with a 10-mm diameter and a 2-mm height were sterilized by autoclaving at 121 °C for 15 min and incubated with the commercially available bacterial strains ATCC(American Type Culture Collection- P.g 33277 and A.a 29522)mixture of Aggregatibacter actinomycetemcomitans(A.a) and Porphyromonas gingivalis(P.g).After a 2-week incubation period with the mixture of bacteria to develop a mixed species biofilm, the discs were divided into three groups: (1) no treatment (control), (2) 445 nm laser (test), (3) 970 nm laser (test). For each laser wavelength (445 and 970 nm), the discs were exposed to 1.0 W and 2.0 W in continuous wave mode for the times points of 15, 30, and 60 s. The antimicrobial efficacy was assessed by qPCR. A significant reduction in the levels of both species of bacteria was observed between control and the laser intervention groups. A higher efficacy for the 445 nm diode laser against Porphyromonas gingivalis and a similar efficacy against Aggregatibacter actinomycetemcomitans was observed as compared to the 970 nm group. 445 nm wavelength represents a potential and effective laser wavelength which can be used for the management of peri-implant infection. The present study findings also need to be further validated through clinical interventional trials.

To review current literature and synthesize clinical outcomes related to different low-level laser techniques as a complement to basic periodontal therapy (BPT). Electronic searches were conducted in PubMed, Cochrane, and Scopus, and clinical trials published from January 2013 to August 2023 using photobiomodulation as a complement to basic periodontal therapy, with a clear description of the laser technique, were included. The risk of bias was assessed using the Joanna Briggs Institute Critical Assessment Checklist. Estimates of interest were calculated using random effects meta-analyses. A total of 947 references were retrieved, and 22 studies were included for qualitative synthesis. Ten studies used intrasulcular laser techniques, with 89% using infrared wavelength, and 12 studies used transgingival techniques, with 61.5% using red wavelength. The frequency of photobiomodulation after BPT ranged from 1 to 9 sessions, with follow-up periods ranging from 5 days to 12 months. Risk of bias was considered low in 16 studies and moderate in six studies. Meta-analysis of 13 studies showed that BPT reduced probing depth at 4-, 12- and 24-weeks post-treatment, and improved clinical level attachment at 6-, 12- and 24-weeks post-treatment. Studies suggest that photobiomodulation may be a valuable complement in the treatment of periodontitis, especially using transgingival application technique.

Mesenchymal stem cells can differentiate into specific cell lineages in the tissue repair process. Photobiomodulation with laser and LED is used to treat several comorbidities, can interfere in cell proliferation and viability, in addition to promoting responses related to the physical parameters adopted. Evaluate and compare the effects of laser and LED on mesenchymal cells, with different energy doses and different wavelengths, in addition to viability and wound closure. Mesenchymal stem cells derived from human adipocytes were irradiated with laser (energy of 0.5 J, 2 J and 4 J, wavelength of 660 nm and 830 nm), and LED (energy of 0.5 J, 2 J and 4 J, where lengths are 630 nm and 850 nm). The wound closure process was evaluated through monitoring the reduction of the lesion area in vitro. Viability was determined by analysis with Hoechst and Propidium Iodide markers, and quantification of viable and non-viable cells respectively Data distributions were analyzed using the Shapiro-Wilk test. Homogeneity was analyzed using Levene's test. The comparison between the parameters used was analyzed using the Two-way ANOVA test. The T test was applied to data relating to viability and lesion area. For LED photobiomodulation, only the 630 nm wavelength obtained a significant result in 24, 48 and 72 h (p = 0,027; p = 0,024; p = 0,009). The results related to the in vitro wound closure test indicate that both photobiomodulation with laser and LED demonstrated significant results considering the time it takes to approach the edges (p < 0.05). Considering the in vitro experimental conditions of the study, it is possible to conclude that the physical parameters of photobiomodulation, such as energy and wavelength, with laser or LED in mesenchymal stem cells, can play a potential role in cell viability and wound closure.

To investigate the changes in meibomian gland dysfunction (MGD) and tear matrix metalloproteinase-9 (MMP-9) levels in patients with moderate-to-severe MGD after combined treatment with intense pulsed light (IPL) therapy and cyclosporine 0.05%. Thirty-six patients concurrently treated with IPL and cyclosporine 0.05% ophthalmic drops were retrospectively enrolled. Tear break up time (TBUT), corneal and conjunctival staining scores, Schirmer test, and ocular surface disease index (OSDI) questionnaire responses were recorded. Meibum quality, consistency, and eyelid margin telangiectasia were evaluated. MMP-9 levels were examined by the positivity and signal intensity of red lines (scored 0-4). IPL was performed four times with a vascular filter at 2-week intervals, followed by a 1-month follow-up after treatment cessation. Immediately after each IPL treatment, gentle meibomian gland expression was performed in both the upper and lower eyelids using meibomian gland expressor forceps. TBUT (1.88 ± 1.02 s to 3.12 ± 1.08 s, p < 0.001), corneal and conjunctival staining (6.19 ± 2.11 to 3.12 ± 1.89, p < 0.001), Oxford staining grade (2.66 ± 0.89 to 1.35 ± 0.76, p < 0.001), and OSDI (52.97 ± 21.86 to 36.36 ± 22.45, p < 0.001) scores significantly improved after the combined treatment. Meibum quality, consistency and lid margin telangiectasia showed significant post-treatment improvement in both the upper and lower eyelids. MMP-9 positivity showed a significant decrease (97-69%, p = 0.026) with a reduction in signal intensity (2.72 ± 0.87 to 2.09 ± 0.95, p = 0.011). The combination of IPL therapy and 0.05% cyclosporine eye drops effectively treats moderate-to-severe MGD by reducing symptoms and signs of MGD and by decreasing ocular surface MMP-9-associated inflammation.

Due to antimicrobial drug resistance, there is a growing interest in the development of light based alternative antibacterial therapies. This research work is focused on the inactivation of Escherichia coli (E. coli) by exploiting the absorption bands 405, 505, 542, 580 and 631 nm of its indigenously produced Protoporphyrin IX (PpIX) excited by three LEDs with broad emission bands at 418, 522 and 630 nm and two laser diodes with narrow emission bands at 405 and 635 nm. Fluorescence spectroscopy and plate count method have been employed for studying the inactivation rate of E. coli strain in autoclaved water suspension. It has been found that LEDs at 418, 522 and 630 nm produced pronounced antimicrobial photodynamic effect on E. coli strain comparing laser diodes at 405 and 635 nm, which might be attributed to the overlapping of broad emission bands of LEDs with the absorption bands of PpIX than narrow emission bands of laser diodes. Particular effect of LED at 522 nm has been noticed because its broad emission band overlaps three absorption bands 505, 542 and 580 nm of PpIX. The gold standard plate count method strongly correlates with Fluorescence spectroscopy, making it an innovative tool to administer bacterial inactivation. The experimental results suggested the development of a light source that entirely overlap absorption bands of PpIx to produce a pronounced antimicrobial photodynamic effect, which might become an effective modality for in vivo disinfection of antibiotic resistant microbes in wounds and lesions.

Objectives: In-vitro studies were performed on dentin of extracted human molars to investigate the effectiveness of 9.3 μm CO₂ laser irradiation to occlude dentinal tubules. The observed occlusion of dentinal tubules with the irradiation was compared with application of three reagents: 2% Sodium Fluoride gel, an aqueous solution of hydroxyapatite nanoparticles and an equal mix of the two. We show that 9.3 μm CO₂ laser irradiation occludes dentinal tubules, and the use of laser irradiation produces better occlusion of the opened tubules compared to the use of topical reagents.

Methods: Nine extracted and cleaned human molars were cut to obtain dentin disks of thickness of 3-5 mm. Each disc was divided into four quarters, and each quarter served as two samples corresponding to irradiated and non-irradiated group counterparts. Five disks were used to study the effect of various laser irradiation energies on the dentinal tubules to find a good pulse fluence for occlusion of the dentinal tubules, and four disks were used for studying the effects of reagents and irradiation at the pulse fluences found in the first part of the study. The samples were irradiated with a beam diameter of 1 mm (1/e²) at 15 Hz pulse repetition rate, scanned automatically using a set of scanning mirrors. Samples were imaged using Scanning Electron Microscope (SEM) which were processed to determine tubule diameter. Safety of the irradiation treatment was investigated on 6 samples by measuring pulpal temperature rise. The effect of three topical reagents corresponding to 2% Sodium Fluoride gel (F), Hydroxyapatite nanoparticles (HA) and an equal mix of F and HA (HAF) on dentinal tubule occlusion was evaluated and compared with the laser irradiation.

Results: In all examined cases, laser irradiation at a fluence of 0.81 J/cm² resulted in a temperature increase less than 3 °C which is safe, and no surface cracking was observed. There is a threshold pulse fluence of 0.27 J/cm² above which, laser produced surface melting. At a pulse fluence of 0.81 J/cm² a layer of recast of melted dentin was formed. Under this layer, peritubular dentin melting and occluding of the dentinal tubules was observed. Application of either F or HA or HAF did not produce visible occlusion effect on open tubules after washing and microbrushing with excess distilled water.

Conclusions: 9.3 μm CO2 laser irradiation on extracted human molar dentin at pulse fluence of 0.81 J./cm² resulted in tubule area reduction by 97% without rising pulpal temperatures to unsafe levels.

The evolution of laser medical devices for benign prostatic hyperplasia (BPH) treatment aims to enhance vaporization, coagulation, or tissue removal. In this study, we aim to evaluate the effectiveness and safety of the innovative application of insulated-gate bipolar transistor (IGBT) xenon lamp-pulsed drive technology holmium laser in endoscopic prostate enucleation operations using canine models. Six canines were used as an experimental unit, the breed of the canine unit used was beagle. Each canine served as its own control to minimize the number of experimental units. Endoscopic enucleation, performed by a single surgeon, involved enucleating the left hemi-prostate, leaving the right hem-prostate untouched to serve as the control. Throughout the study period, all canines maintained good health. No adverse events were observed in all six canines. Postoperatively, there were no indications of redness, swelling, or other adverse effects at the surgical sites. No abnormalities were observed in the appearance and morphology of major organs. The prostate and bladder, removed for further pathological evaluation, exhibited no abnormalities in size, color, or texture. No abnormalities or inflammation were observed, and the tissues were free of adhesions, indicating successful healing. In conclusion, our comparison of preoperative and postoperative parameters in canines suggests that the IGBT pulsed laser, at a power setting of 100 W, demonstrates characteristics of safety, efficacy, minimal tissue damage, and no major postoperative complications. This study establishes a theoretical foundation for future applications in human settings, encouraging further exploration of the IGBT holmium laser's potential in clinical practice.

Non-small cell lung cancer (NSCLC) is a prevalent malignant tumor, and the commonly treatment modalities include surgery, radiotherapy, chemotherapy, etc. Currently, CT-guided percutaneous radiofrequency ablation (RFA) for the treatment of cancers has been widely performed. This study aimed to evaluate the safety and efficacy of this therapy in NSCLC patients. Thirty-five NSCLC patients were enrolled in this study and all received CT-guided percutaneous RFA therapy. The outcome measures included the changes in forced respiratory volume in the first second (FEV1), total lung volume (TLC), lesion size and computed tomography (CT) values of the region of interest (ROI) before and after treatment. The main efficacy measures comprised complete tumor ablation and local recurrence after initial treatment, as well as the objective response rate (ORR) and disease control rate (DCR) after 6 months of treatment. After receiving CT-guided percutaneous RFA therapy, the target lesion was effectively controlled and CT values gradually decreased. Besides, no significant changes were observed in the patient's lung function, postoperative complications were experienced by a total of 10 patients, primarily including pneumothorax, infection, lung hollowing. Fortunately, all these complications were successfully managed with appropriate treatment. Following the initial RFA treatment, 31 patients (88.57%) achieved complete ablation, while 6 patients experienced local recurrence. After 6 months of treatment, the ORR and DCR were found to be 68.57% and 82.86% respectively. CT-guided percutaneous RFA has demonstrated favorable safety and efficacy in the treatment of patients with NSCLC at different stages, which represented a promising therapeutic modality.

This article discusses current research on the detection of cervical and breast cancer using in vitro Raman spectral analysis of human serum by Cao et al. (2024) which was published in the Lasers in Medical Science journal. Despite the high accuracy of the suggested approach (93%), the demonstrated findings could be treated unclear due to possible overestimation of the classification models.