Lasers in Medical Science最新文献

This study aimed to investigate the effects of diode laser parameters on the thermal response and surface morphology of RBM (Resorbable Blast Media), SLA (Sandblasted, Large-grit, Acid-etched), and additively manufactured Ti6Al4V titanium surfaces, and to determine whether surface type influences heat distribution and integrity, which is clinically relevant in peri-implantitis treatment. A total of 144 titanium discs with three different surface treatments (RBM, SLA, and additively manufactured Ti6Al4V as the control group) were irradiated with a 940 nm diode laser at varying power levels (1 W, 2 W, 3 W), durations (30 s, 60 s), and modes (continuous, pulsed). Surface temperatures were recorded using thermal imaging. Morphological and elemental changes were evaluated via Scanning Electron Microscopy (SEM) and Energy-Dispersive X-ray Spectroscopy (EDS) analyses. A four-way Aligned Rank Transform Analysis of Variance (ART ANOVA) was used to analyze the effects of variables. Temperature increases were significantly influenced by all tested variables (p < 0.001). The RBM group exhibited the highest peak temperature (185 °C at 3 W pulsed mode, 60 s), while SLA surfaces consistently showed the lowest (39.9 °C at 1 W continius mode, 30 s). Pulsed mode and longer exposure times produced higher temperatures, except at 1 W, which resulted in the lowest temperature rise regardless of surface treatment. SEM images revealed mild surface alterations at higher power, with RBM exhibiting localized depressions and SLA displaying minor fragmentation of surface textures. EDS analysis indicated no major changes in elemental composition post-irradiation. The study highlights that different titanium surface types respond distinctly to diode laser irradiation, with RBM surfaces being more thermally reactive. Uniform laser protocols may not be appropriate for all implant surfaces. Careful consideration of power, duration, and surface characteristics is essential to avoid potential thermal damage during peri-implantitis treatment.

This study aimed to evaluate the efficacy of low-level laser application in the treatment of periodontal intra-bony defects. Two independent reviewers conducted searches for articles published in English. The primary objective was to investigate whether clinical parameters improved in periodontal regeneration therapy with and without low-level laser therapy (LLLT). The primary outcome was probing depth (PD), while the secondary outcome measures were clinical attachment level (CAL), gingival recession (GR), and bone defect depth. After screening and eligibility assessment, eight studies were included in the analysis. For the primary outcome measure (PD), after sensitivity analysis, the reduction in PD from baseline to 3 months was greater in the laser group than in the non-laser group (P = 0.02). For the secondary outcome measure (CAL), after sensitivity analysis, the increase in CAL from baseline to 3 months was greater in the laser group (P < 0.001). Although laser therapy may be beneficial for early wound healing, the current evidence does not support its routine use in periodontal regenerative surgery. Further high-quality studies are warranted to evaluate its clinical efficacy.

Purpose: To evaluate the clinical utility of endoscopic laser speckle contrast imaging (eLSCI) for intraoperative assessment of parathyroid gland (PTG) perfusion and functional preservation.

Methods: Fifteen patients undergoing unilateral/bilateral thyroidectomy at The Affiliated Lihuili Hospital of Ningbo University (November 2024 to April 2025) were prospectively enrolled. PTG perfusion was quantified using eLSCI by recording blood flow index (BFI) before and after thyroid resection. Serum parathyroid hormone (PTH) and calcium levels were measured preoperatively, at 15-min post-resection, and 24-h postoperatively. Pearson correlation analysis was used to assess the linear association between perfusion and functional parameters, while Spearman's rank correlation test was concurrently performed to verify the robustness.

Results: A significant correlation existed between the BFI change ratio and PTH change ratio at 15-min post-resection (r = 0.672, p = 0.006) and 24-h postoperatively (r = 0.671, p = 0.006). No significant correlation was observed between BFI change ratio and serum calcium change ratio at either timepoint (p > 0.05).

Conclusion: The eLSCI system enables real-time quantitative assessment of intraoperative parathyroid perfusion and demonstrates feasibility in predicting postoperative parathyroid function, holding significant potential for clinical application.

Gingival pigmentation is a common cosmetic concern that can negatively impact a patient's smile aesthetics. Laser-assisted depigmentation has emerged as a reliable and effective treatment modality. The study aimed to compare the efficacy, comfortability of the patient, and the post-operative outcomes among patients who underwent either an ablative or a non-ablative diode 450 nm laser for gingival depigmentation. A split-mouth, single-blind, randomized controlled trial was conducted on 20 subjects exhibiting physiological pigmentation scores of 2 or more, as assessed by the Dummett index. A diode laser emitting 450 nm wavelength was employed. One side of each subject's mouth was randomly assigned to receive ablative laser treatment, while the contralateral side received non-ablative treatment. Primary outcome measures included changes in Oral Pigmentation Index and Melanin Pigmentation Index scores at baseline and at 1, 6, and 12 months' post-treatment. Patient perception of pain and discomfort was assessed using a modified McGill Pain Questionnaire. Both ablative and non-ablative techniques demonstrated significant reductions in OPI and MPI scores at all follow-up time points. Immediate and total depigmentation was achieved using ablative techniques, which showed fewer rates of re-pigmentation but higher intraoperative discomfort. In contrast, non-ablative techniques result in less pain but required more sessions to obtain optimal results. The choice of technique should be individualized based on patient preferences and clinician expertise. Non-ablative treatment may be preferred for patients seeking minimal discomfort and rapid healing, while ablative treatment may be suitable for patients who prioritize complete pigment removal in one session.

To evaluate and compare clinical outcomes, radiographic healing and regenerative biomarkers in laser-irradiated and non-irradiated groups undergoing regenerative endodontics in immature permanent teeth over a 12-month follow-up period. Twenty-eight patients with necrotic immature roots were assigned to one of two groups: a control group (n = 14) receiving standard regenerative endodontic procedure (REP) with a mock laser application, or an experimental group (n = 14) receiving standard REP with adjunctive low-level laser therapy (LLLT). Both groups underwent initial medication with double antibiotic paste. In the experimental group, a diode dental laser (810 nm, 4.5 J/cm², 0.3 W, 9 s) was applied to the apical third every 48 h for 14 days. After 21 days, intracanal bleeding was induced, and blood samples were collected for regenerative marker analysis using ELISA. Mineral trioxide aggregate was placed, followed by coronal restoration. Clinical symptoms and radiographic healing were monitored over 12 months, with statistical analysis performed using the independent t-test at a 95% confidence level. Clinically, both groups demonstrated high success rates (85.7% in the laser group vs. 78.6% in the control group; p = 0.83). No statistically significant differences were observed when pain and radiographic parameters were compared over time between the groups. Considering the biomarkers, only DSPP expression was significantly higher in the laser group (p = 0.03). For the other biomarkers (VEGF, TGF-β, MMP-8, PDGF-BB), the laser group showed numerically higher mean values, but these differences did not reach statistical significance (all p > 0.05). This study demonstrates that adjunctive low-level laser therapy (LLLT) during regenerative endodontic procedures produced comparable clinical and radiographic outcomes to standard treatment, with a significant increase in DSPP expression suggesting early molecular activation. While these findings indicate potential regenerative benefits, larger multicenter studies with extended follow-up are required to validate LLLT as an adjunct in clinical protocols. Trial registration: This trial was registered in the Clinical Trials Registry India (CTRI) under registration number CTRI/2024/01/062114 dated 31/01/2024.

This study aimed to compare the efficacy of low-power laser therapy (LPLT) and low-frequency ultrasound (LFU) in reducing pain and improving quality of life in patients with diabetic polyneuropathy (DPN). A randomized controlled trial was conducted involving 55 patients with DPN, randomly assigned to three groups: LPLT (n = 18), LFU (n = 15), and control (n = 22). The LPLT group received treatments three times weekly for four weeks at 6 J/cm² using 808 nm and 905 nm wavelengths. The LFU group received treatments three times weekly for four weeks at 1 MHz, 0.5 W/cm², and 20% duty cycle. All interventions were administered alongside standard medical care. Baseline and post-intervention assessments included the Michigan Neuropathy Screening Instrument (MNSI) and Quality of Life in Diabetic Neuropathy (QOL-DN) measures. At baseline, significant differences were observed in patient-reported MNSI scores (p = 0.001), with the LPLT group reporting the highest scores. Post-intervention, all groups showed reductions in MNSI scores, but between-group differences were not significant (p = 0.292). The LPLT group exhibited the largest mean reduction (-2.39) in patient-reported MNSI scores, though the change only approached significance (p = 0.057). For QOL-DN, the LPLT group showed the greatest improvement in symptom scores (Mean=-2.55, p = 0.023) and problem scores (Mean=-7.05, p < 0.001). ANCOVA confirmed a significant group effect for QOL-DN problem scores (p = 0.007), with the LPLT group showing significantly greater improvement than controls (p = 0.006). LPLT may have potential for improving quality of life and neuropathy symptoms in DPN patients, but the limited between-group differences indicate that its clinical utility remains uncertain. Larger, multicenter trials with longer follow-up are needed to confirm these preliminary findings and establish clinical relevance.

Monopolar radiofrequency (RF) devices are widely used for skin tightening, wrinkle reduction, and body contouring. However, frequency-dependent differences in energy absorption and tissue remodeling remain insufficiently characterized. This study aimed to compare the thermal distribution and histological responses induced by 6.78‑ and 2‑MHz monopolar RF, as well as their sequential combination. Finite-element computational modeling was used to simulate electric field propagation and heat diffusion in multilayered skin with varying subcutaneous fat thicknesses and fibrous septa configurations. In vivo experiments were conducted on porcine skin treated with 6.78‑, 2‑, and dual‑frequency RF modes. Histologic changes were evaluated using hematoxylin and eosin, Masson's trichrome, and Verhoeff-van Gieson staining. Apoptotic cell death was assessed using the terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay to evaluate adipocyte viability. Computational modeling demonstrated that 2‑MHz RF produced broader and deeper thermal effects within the adipose tissue, whereas 6.78‑MHz RF generated more localized heating along the fibrous septa. Dual-frequency RF combines these effects, creating pronounced thermal reactions at the dermosubcutaneous junction. Histological analysis revealed significant collagen and elastin remodeling across the dermis and fibrous septa in dual-frequency-treated specimens, with no evidence of adipocyte apoptosis. Moreover, remodeling changes were more extensive and persistent at later time points, suggesting that dual-frequency treatments have a greater tissue remodeling potential compared with single-frequency applications. Dual-frequency monopolar RF effectively promoted extracellular matrix remodeling in the dermis and subcutis while preserving adipocyte viability, suggesting its use as a safe and versatile modality for skin rejuvenation and contouring.