This study aimed to comparatively evaluate the effectiveness of different irrigation solutions and activation techniques in removing calcium hydroxide (CH) from standardized artificial grooves located in the apical third of root canals. Ninety extracted single-rooted human maxillary central incisors were instrumented using a standardized preparation protocol. Artificial grooves were created in the apical third of split roots and filled with CH paste. Specimens were randomly divided into two irrigation groups: 1.5% sodium hypochlorite (NaOCl) + 0.1% octenidine dihydrochloride (OCT) or 1.5% NaOCl + 17% ethylenediaminetetraacetic acid (EDTA). Each group was further subdivided according to the activation technique: conventional needle irrigation (CNI), passive ultrasonic activation (PUA), or laser-activated irrigation (LAI). Data were analyzed using Kruskal-Wallis and Mann-Whitney U tests with Bonferroni correction (α = 0.05). Significant differences were observed among the groups (p < 0.001). OCT combined with PUA showed the lowest residual CH scores and performed significantly better than OCT + CNI. OCT demonstrated superior CH removal compared with EDTA under CNI and PUA conditions. The OCT + PUA protocol was the most effective approach for CH removal.

Burns result in hypertrophic scarring, causing functional impairment, cosmetic and psychological concerns. Fractional CO2 laser and botulinum, have shown promise in treatment. To evaluate the effectiveness of fractional laser treatment alone and combined with botulinum toxin A, delivered either through injections or topical application as fractional laser-assisted drug delivery in hypertrophic burn scar. A randomized comparative trial involving 16 patients with post-burn hypertrophic scars. The scar of each patient was divided into 3 sections: (1) fractional CO2 laser combined with intralesional botulinum toxin type A, (2) fractional CO2 laser monotherapy, and (3) fractional CO2 laser with laser-assisted drug delivery of BTXA. Patients received three treatment sessions at monthly intervals, followed by a three-month follow up. Clinical outcomes were evaluated using the Vancouver Scar Scale. Intralesional BTXA demonstrated superior efficacy, achieving the greatest reductions in VSS (- 58.25%). Intralesional BTXA in combination with fractional CO2 laser represents a highly effective treatment for post-burn hypertrophic scars, offering superior improvements in scar pliability, contour, and patient comfort compared with laser monotherapy or LADD. These findings support intralesional BTXA as the preferred therapeutic approach, while highlighting the potential of combination protocols for optimizing scar outcomes.

Hybrid 755-nm/1064-nm laser systems may improve hair reduction by combining strong melanin absorption with deeper dermal penetration. This study compared a synchronized hybrid dual-wavelength mode with a single 755-nm alexandrite mode. In this prospective, single-blind, split-body controlled trial with alternating allocation, 41 adults underwent three laser sessions at 4-week intervals using one integrated platform. One bilateral subsite was treated with single 755-nm mode and the contralateral subsite with hybrid 755-nm/1064-nm mode. The primary outcome was change in trichoscopic hair thickness from baseline to 20 weeks. Secondary outcomes included hair density, pain, satisfaction, and adverse events. Thirty-six participants completed the per-protocol analysis. Hair thickness decreased significantly with both modes, with a greater reduction after hybrid treatment (between-mode difference, 0.00461 ± 0.00745 mm; 95% CI, 0.00209-0.00713; p = 0.0007), corresponding to an approximately 28% larger relative reduction. Hair density reduction did not differ significantly (p = 0.238). Pain was slightly higher with hybrid treatment at the second session only, but satisfaction was comparable. No device-related adverse events occurred at hybrid-mode sites. The synchronized hybrid 755-nm/1064-nm mode produced superior hair-thickness reduction compared with single 755-nm treatment, with comparable satisfaction and favourable tolerability.

Pulsed dye lasers (PDLs) are commonly used for early postoperative scar modulation, but evidence for fractionated picosecond lasers is limited. This prospective split-scar study compared the efficacy and safety of a fractionated 1064-nm picosecond Nd: YAG laser with PDL in the early treatment of linear postoperative scars. Fourteen adults received the picosecond Nd: YAG laser on one half of each scar and PDL on the other. Treatments were initiated immediately after suture removal on postoperative day 14 (week 0) in all participants and repeated at weeks 4 and 8. Outcomes were assessed at weeks 0, 4, 8, and 16 using the Vancouver Scar Scale (VSS), Patient and Observer Scar Assessment Scale-Observer (POSAS-O), and Manchester Scar Scale (MSS). Patient satisfaction was recorded at week 16. Both treatments significantly improved scar appearance by week 16. The fractionated picosecond Nd: YAG laser showed significant reductions in VSS, POSAS-O, and MSS scores, while PDL produced similar improvements. No significant differences were found between treatments over time, and statistical testing confirmed equivalence at week 16 across all scales. Patient satisfaction scores were comparable, and no serious adverse events occurred. Overall, the fractionated 1064-nm picosecond Nd: YAG laser produced short-term postoperative scar outcomes statistically equivalent to those observed with PDL, with good tolerability.

To evaluate whether diffractive intraocular lenses (IOLs) reshape 577-nm retinal laser photocoagulation spots in a model eye. A standardized model eye received 577-nm continuous-wave laser photocoagulation through a retinal contact lens at fixed settings: 200-µm spot, 100 mW, and 0.2 s. One monofocal IOL (ZCB00) and two diffractive IOLs (ZMB00, ZXR00) were tested in 15 sessions; a no-IOL condition provided power normalization and quality control. Delivered power was measured calorimetrically and normalized to no-IOL controls. Thermal-paper responses were threshold-segmented to quantify core fraction and disk area. Session-blocked models compared pooled r = 3 mm values; C-to-r = 3 mm changes were used to assess field-dependent effects. At pooled r = 3 mm, core fraction was 0.406 (95% CI, 0.382-0.430) for ZCB00, 0.179 (0.155-0.203) for ZMB00, and 0.201 (0.177-0.225) for ZXR00. Mean differences versus ZCB00 were - 0.227 (95% CI, - 0.261 to - 0.193) for ZMB00 and - 0.205 (- 0.239 to - 0.171) for ZXR00 (both Holm-adjusted P < 0.001). Disk area ratios versus ZCB00 were 0.754 (95% CI, 0.704 to 0.808) for ZMB00 and 0.682 (0.637 to 0.731) for ZXR00 (both Holm-adjusted P < 0.001). Normalized delivered power remained close to unity (0.993-0.997). C-to-r = 3 mm comparisons showed larger morphology changes for diffractive IOLs, whereas normalized delivered power changed little with radius. Under the specified 577-nm model-eye conditions, the tested diffractive bifocal and EDOF IOLs altered threshold-defined photothermal spot morphology relative to the monofocal control, while normalized aperture-integrated power remained near unity, suggesting field-dependent redistribution of target-plane irradiance.

This study aimed to evaluate the short-term effects of photobiomodulation (PBM) on stem cells from human exfoliated deciduous teeth (SHEDs) cultured on electrospun polylactic acid (PLA) microfibrous scaffolds. The scaffolds were characterized by scanning electron microscopy, X-ray diffraction, thermogravimetric analysis, and differential scanning calorimetry. SHEDs were seeded onto the scaffold surface and assigned to three groups: nonirradiated control (C), L0.5 (0.5 J/cm²), and L1 (1.0 J/cm²). PBM was delivered with a 660 nm diode laser at 0 and 48 h after the initial irradiation time point. Cell metabolic activity was assessed at 24, 48, and 72 h using the Alamar Blue assay. Qualitative viable-cell distribution and cell-scaffold interactions were evaluated by Live/Dead staining and scanning electron microscopy, respectively. SHEDs remained viable on the PLA microfibrous scaffold and showed increasing metabolic activity over time. Compared with the control group, L1 presented higher Alamar Blue reduction values at 48 and 72 h, with the highest metabolic activity observed at 72 h. Live/Dead images showed qualitatively more extensive viable-cell colonization of the scaffold surface in the irradiated groups, without an apparent increase in dead-cell staining. Scanning electron microscopy revealed SHED adhesion to the microfibrous scaffold in all groups and qualitatively more extensive cell coverage after irradiation, particularly in L1. Electrospun PLA microfibrous scaffolds supported short-term SHED culture, and PBM at 1.0 J/cm² increased SHED metabolic activity and was associated with favorable qualitative cell-scaffold interactions. These findings provide preliminary support for PBM as an adjunctive biophysical strategy for improving early cellular responses in SHED-seeded electrospun PLA scaffolds.

Exercise-induced muscle damage (EIMD) occurs after unaccustomed eccentric exercise and may impair muscle recovery. Preconditioning with photobiomodulation (PBM) or ischemic preconditioning (IPC) may mitigate EIMD; however, no study has directly compared their effectiveness. This study aims to compare the effects of PBM and IPC applied prior to eccentric exercise on indirect markers of EIMD and associated perceptual responses. We hypothesized that MVIC trajectories would differ among the PBM, IPC, and sham groups, with PBM expected to provide greater preservation of MVIC than IPC. A prospective, randomized, placebo-controlled clinical trial with concealed allocation, blinded outcome assessors and statistician, and intention-to-treat analysis will be conducted. Healthy men (18-35 years) will be randomly allocated to PBM, IPC, or sham groups (n = 15 per group). After the intervention, participants will perform an eccentric exercise protocol for the elbow flexors consisting of 30 repetitions using a dumbbell load numerically matched to maximal voluntary isometric contraction (MVIC) values, with 45-second rest intervals. The primary outcome will be MVIC. Secondary outcomes include rate of force development, delayed-onset muscle soreness, pressure pain threshold, ultrasound echo intensity, range of motion, perceived exertion, and affective responses. Outcomes will be assessed at baseline, immediately after exercise (only MVIC), and at 24-, 48-, and 72-hours post-exercise. The primary analysis will assess the group × time interaction on MVIC using linear mixed-effects models, while secondary outcomes will be analyzed exploratorily. This study will provide, to our knowledge, the first direct comparison between PBM and IPC as preconditioning strategies to attenuate EIMD. The findings may help determine the most effective and clinically applicable intervention by considering both physiological and perceptual responses, thereby supporting decision-making in clinical and sports settings.Trial registrationBrazilian Registry of Clinical Trials (REBEC), RBR-6gr5kf; registered February 19, 2020; amended August 26, 2026.

Neuropathic pain is associated with sensory abnormalities and remains difficult to treat. Photobiomodulation therapy (PBMT) has emerged as a non-pharmacological approach with analgesic potential; however, sex-related differences in treatment responses remain poorly understood. We investigated the effects of PBMT in male and female rats subjected to chronic constriction injury (CCI) of the sciatic nerve. Animals received infrared PBMT administered three times per week during ten sessions, and nociceptive responses were assessed using mechanical hyperalgesia and tactile allodynia throughout treatment. CCI induced significant nociceptive hypersensitivity in both sexes. PBMT progressively increased withdrawal thresholds and reduced pain-like behaviors. Females exhibited greater relative recovery in both mechanical hyperalgesia and tactile allodynia, whereas males maintained higher absolute nociceptive thresholds throughout the experimental period. Estrous cycle analysis revealed reduced pain sensitivity during metestrus compared with estrus and proestrus. These findings demonstrate that PBMT effectively attenuates neuropathic pain-like behaviors in both sexes and suggest that biological sex and hormonal status may influence therapeutic responses. The results support the inclusion of sex as a biological variable in preclinical photobiomodulation studies.

In this study, we investigate the effects of low-level laser therapy (LLLT) at different wavelengths on lymphedema to further determine the appropriate protocol and effectiveness of LLLT in patients with breast cancer-related lymphedema (BCRL). A randomized controlled trial was conducted involving 46 patients with BCRL. Participants were assigned to receive 904 nm LLLT, 650 nm LLLT, or sham treatment. ICG lymphography was used to assess dermal backflow as a marker of lymphatic dysfunction. Ultrasonography was used to assess subcutaneous thickness and tissue mechanical properties; shear wave velocity (SWV), with higher values indicating greater tissue stiffness, was measured using shear wave elastography. Extracellular fluid volume and local tissue water content were evaluated using multifrequency bioelectrical impedance analysis (MFBIA) and tissue dielectric constant (TDC), respectively. No significant between-group differences were observed in ICG lymphography, MFBIA, or TDC outcomes. For ultrasonographic outcomes, the overall between-group difference in the change in upper-lateral SWV ratio was significant (p = 0.029), and Bonferroni-adjusted post-hoc analysis showed a greater reduction in Group A (904 nm) than in Group B (650 nm) (adjusted p = 0.026). Within Group A, SWV ratios decreased significantly at the lower-lateral site and at the LLLT treatment site. These site-specific findings were not accompanied by measurable changes in lymphatic transport or fluid-related outcomes. Adding 904 nm-650 nm LLLT to conventional decongestive therapy did not produce significant additional effects on extracellular fluid-related or lymphatic functional outcomes. Site-specific reductions in SWV observed with 904 nm LLLT suggest a potential wavelength-dependent effect on local tissue mechanical properties; however, these findings are limited and should be considered exploratory. Larger adequately powered studies with prespecified primary outcomes and longer follow-up are required.

Achilles tendon injuries are common, especially among athletes, and their treatment remains challenging. Reduced muscle strength and immobility can exacerbate tendon stiffness, leading to disability. This study investigated the effects of adipose tissue-derived mesenchymal stem cell exosomes and low-level laser therapy (LLLT) on muscle and Achilles tendon elasticity in a rabbit model. Twelve New Zealand white rabbits underwent ultrasound imaging of Achilles tendons and gastrocnemius muscles with a 40 MHz probe during flexion and dorsiflexion. Foot stress during movement was measured. To create a partial tendon injury, a 5 mm longitudinal incision, 3 mm deep, was made in the Achilles tendon. Male rabbits were randomly divided into four groups: control, LLLT (830 nm, 15 mW, 3 J/cm[2]), exosome injection (200 µg/mL), and combined LLLT with exosomes. Treatments were applied on days 1, 8, and 15. Ultrasound evaluations were performed before injury, immediately after, and on days 8 and 21. Tendon and muscle samples were analyzed histologically with hematoxylin-eosin staining. On day 21, the force applied to induce flexion and dorsiflexion of the Achilles tendon and gastrocnemius muscle significantly increased in the combined treatment group compared to the others (P < 0.05). The thickness strain of both muscle and tendon improved significantly with combination therapy (P < 0.05). Histology showed compact, parallel collagen fibers and a well-organized extracellular matrix in tendons treated with LLLT and exosomes. No inflammation was observed, and muscle atrophy was reduced. Combining low-level laser therapy with exosomes derived from ADSCs enhanced the histological, ultrasound-derived, and mechanical aspects related to Achilles tendon repair. This included improvements in tendon and gastrocnemius strain, as well as flexion and dorsiflexion force.

To compare the clinical efficacy of erbium, chromium-doped yttrium scandium gallium garnet (Er, Cr: YSGG) laser versus conventional air-rotor handpiece for caries removal in primary teeth and their effects on children's anxiety and pain levels, to provide evidence for optimizing pediatric dental treatment. A total of 90 children (aged 6-10 years) with primary tooth caries were enrolled. Using a split-mouth design, two carious teeth from each child were randomly assigned to air-rotor handpiece treatment (Group A, 90 teeth) or Er, Cr: YSGG laser treatment (Group B, 90 teeth). Clinical efficacy, restoration quality (United States Public Health Service [USPHS] criteria), masticatory function (bite force, chewing efficiency), adverse events, and children's anxiety (Venham Anxiety and Behavior Rating Scale, Faces Image Scale [FIS], pulse rate) and pain levels (Wong-Baker FACES® Pain Rating Scale) were compared. Group B exhibited significantly lower Venham scores, pulse rates, FIS scores, and Wong-Baker pain scores post-treatment (P < 0.01). Additionally, no significant difference was observed in overall clinical efficacy (Group A 83.33% vs. Group B 91.11%, P = 0.18). However, Group B showed significantly better USPHS scores in sensitivity, secondary caries, and marginal staining (P < 0.01), greater improvement in masticatory function (P < 0.05) and a lower incidence of adverse events (P = 0.01). Er, Cr: YSGG laser may represent an effective minimally invasive alternative for caries removal in primary teeth, particularly due to its potential benefits in reducing treatment-related pain and anxiety. Further long-term studies are required to confirm its effects on restoration longevity and clinical outcomes.

This study aimed to evaluate the shear bond strength and surface roughness of the enamel after removal of ceramic brackets with CO2 laser. Thirty extracted premolars were randomly assigned to three groups (n = 10): Untreated enamel (GI), Conventional debonding (GII), and CO2 laser debonding (GIII). Polycrystalline ceramic brackets were adhered on the buccal surface of GII and GIII groups, using 35% phosphoric acid and Transbond Plus Color Change resin (3 M Unitek; Monrovia, California, USA); shear bond strength was evaluated with a universal testing machine (EZ Graph; Shimadzu, Kyoto, Japan). Prior to debonding, brackets in the GIII group were irradiated with a CO2 laser (Yoshida Dental MFG; Tokyo, Japan) at a wavelength of 10.6 μm, power output of 6 W, for 5 s, at 5 mm. Each specimen was evaluated for adhesive remnant index score, and enamel surfaces were polished to assess roughness (with and without the CO2 laser) under atomic force microscopy. Ra, Rq, and Ry roughness parameters were analyzed. Statistical analysis was carried out using Student's t-test to evaluate shear bond strength, the Mann-Whitney U to assess the adhesive remnant index, and the Kruskal-Wallis and Dunn's post hoc to examine enamel roughness. GIII group showed statistically significant differences, with a reduction in shear bond strength (p < 0.001) and enamel roughness (p < 0.0083) compared to GII. These findings indicate that CO2 laser irradiation can be considered as an alternative in debonding ceramic brackets in orthodontic treatments.

To evaluate the effectiveness of low-level laser therapy (LLLT) as an adjunct to rehabilitation in reducing pain and improving knee function in adults with MRI-confirmed meniscus injuries. In this randomized, double-blind, placebo-controlled trial, 40 adults with unilateral meniscus injuries were assigned to either an LLLT group or a placebo group. All participants received a standardized rehabilitation program over six weeks. The primary outcome was pain intensity measured using a visual analogue scale (VAS). Secondary outcomes included knee function (Lysholm score), range of motion (ROM), and physical performance tests. Both groups showed significant improvements; however, the LLLT group demonstrated greater reductions in pain and improvements in function, mobility, and ROM compared with the control group (p < 0.01 for all outcomes). The magnitude of improvement exceeded clinically meaningful thresholds, particularly for pain reduction and functional gains. Adjunctive LLLT was associated with greater improvements in pain and functional outcomes compared with rehabilitation alone. LLLT appears to be a safe and potentially effective complementary modality in the conservative management of meniscal injuries.

Postoperative pain, edema, and trismus are frequent complications following impacted mandibular third molar surgery. While photobiomodulation (PBM) is a proposed adjunctive therapy, clinical evidence remains controversial. This study evaluated the effects of single-session extraoral dual-wavelength PBM (650 + 904 nm) applied immediately after extraction on postoperative pain, edema, trismus, and quality of life (QoL). This prospective RCT enrolled 70 patients (mean age: 22.04 ± 2.61 years) with asymptomatic mesioangular impacted mandibular third molars (Pell-Gregory Class IB). Participants were randomized to a PBM (n = 35) or control (n = 35) group. Following standardized surgical extraction by a single surgeon, the PBM group received a 10-minute extraoral application (650 + 904 nm, GaAlAs laser). The primary outcome was postoperative pain, assessed by VAS on postoperative days 2 and 7. Secondary outcomes included QoL (VAS, days 2 and 7), edema (sum of three facial distances), and trismus (maximum interincisal distance), the latter two evaluated at baseline and on postoperative days 2 and 7. On postoperative day 2, pain VAS scores were significantly lower in the PBM group (20.34 ± 24.38 vs. 41.43 ± 25.15; p < 0.001) and QoL scores significantly higher (69.83 ± 25.87 vs. 50.51 ± 23.24; p = 0.002) compared to controls. By day 7, a statistically significant but clinically negligible between-group difference persisted in pain (Mann-Whitney U = 776.5, p = 0.040; mean difference 2.6 mm), while QoL no longer differed significantly between groups (p = 0.154). No significant between-group differences were observed for edema or trismus at any time point (p > 0.05). Single-session extraoral dual-wavelength PBM significantly reduces early postoperative pain and improves QoL on the second postoperative day following impacted third molar extraction, with no significant effect on edema or trismus. The clinically meaningful pain and QoL benefits resolved by day 7, and sham-controlled multi-session trials are warranted.