جستجوی مقالات مرتبط با کلیدواژه « Low-level laser » در نشریات گروه « پزشکی »

To investigate the short-term effects of low-level lasers (LLLs; also known as lowpower laser therapy) on the structure, genetic, and phenotype of cultured human retinal pigment epithelial (hRPE) cells from both adult and neonatal sources.

Cultivated adult and neonatal hRPE cells were irradiated with two types of LLL (630 nm and 780 nm), 1 min daily for five consecutive days.

An increase in doubling time was observed in 630 nm-irradiated adult hRPE cells (P = 0.032). The gene expression profile revealed increased expression of retinoid isomerohydrolase RPE65 (RPE65) (P < 0.01 for 630 nm laser, P < 0.001 for 780 nm laser) and nestin (NES) (P < 0.01 for 630 nm laser) in neonatal hRPE cells, upregulation of RPE65 (P < 0.001 for 780 nm laser) and paired box 6 (PAX6) (P < 0.001 for 780 nm laser) genes in adult hRPE cells, and reduced expression of actin alpha 2 (ACTA2) in 780 nm-irradiated adult hRPE cells (P < 0.001). Except the significant increase of 𝛼-SMA in 780 nm-irradiated neonatal hRPE cells, no significant change was noted in the expressions of other investigated proteins.

Short-term irradiation of neonatal and adult hRPE cells with LLLs may induce multipotency at the transcriptional level. Irradiation of neonatal hRPE cells with LLLs can be associated with increased risk of myofibroblastic transformation; however, adult hRPE cells irradiated with the 780 nm laser have minimal risk of myofibroblastic differentiation. It seems that the 780 nm laser may be a promising option for future photobiomodulation in retinal degenerations in adults.

Alopecia areata (AA) is an autoimmune, inflammatory, non-scarring hair loss in which T-cells target hair follicles. Given that the available therapeutic options generally do not induce and sustain remission of AA effectively and many adverse effects may occur, monochromatic light sources have been recently gaining attention from clinicians. Therefore, the present paper aimed to report the first case in which photobiomodulation therapy (PBMT) with a continuous wave red laser (660 nm) was used as monotherapy for AA.

An isolated round area of complete hair loss was subjected to daily PBMT sessions, resulting in significant regrowth (hair of normal coloration and thickness) within 7 days. On the 21st day, the patient’s aesthetic concern was completely resolved.

PBMT with a continuous wave red laser seems to be a promising therapeutic option for the treatment of AA; however, additional studies are necessary to obtain more robust evidence.

Surgical procedures involving the temporomandibular joint (TMJ) are frequently associated with nerve injuries and subsequent dysfunctions.Considering that traumatic peripheral nerve injuries may resolve slowly and their prognosis is generally unpredictable, the current study aimed to report a clinical case in which both motor (affecting the temporal and zygomatic branches of the facial nerve) and sensory dysfunctions (affecting the auriculotemporal nerve of the trigeminal nerve) following TMJ surgery were effectively treated by using photobiomodulation therapy (PBMT).

Case Report: 

PBMT sessions, involving a total of 30 facial points, were administered twice a week for 10 weeks. The following parameters were utilized: wavelength of 808 nm, energy density of 75 J/cm², power output of 100 mW, total energy of 3 J, and duration of 30 seconds per point. A considerable improvement in both facial asymmetry and muscle function was achieved within 5 weeks, along with a total restoration of cutaneous sensitivity. By the 10th week of PBMT, the facial movement dysfunction was completely resolved.

According to the current case, PMBT seems to be an effective intervention to manage motor and sensory nerve dysfunctions following TMJ surgery.

Thrombocytopenia is usually seen after allogeneic hematopoietic stem cell transplantation (HSCT) and may favor the development of oral bleeding, infections, and ulcerations.

A patient with chronic myelomonocytic leukemia had been submitted to allogeneic HSCT. Within a few days, she developed severe thrombocytopenia and an extensive ulcerative area comprising both lips, which bled spontaneously, as well as smaller ulcers on the tongue mucosa. The lesions were managed using a combination of phototherapies (photobiomodulation and antimicrobial photodynamic therapies), totalizing 4 laser sessions. After 4 days, there was an important reduction in the severity of the lesions, with spontaneous disappearance of the crusts and reepithelization.

The proposed combination of phototherapies would be a suitable therapeutic modality for the management of oral lesions related to platelet disorders induced by oncologic treatments.

The most common type of neck pain is chronic nonspecific pain. There are conflicting opinions about the beneficial effects of a low-level laser in reducing chronic nonspecific neck pain. The aim of this study was to evaluate the efficacy of low-level laser therapy (LLLT) for the treatment of non-specific chronic neck pain.

This study was conducted as a prospective randomized clinical trial. Forty-four patients were randomly divided into two groups: (1) Intervention group (n = 22): LLLT in the red spectra range with a wavelength of 980 (nm) and a power of 16 (J/cm2) was irradiated in the affected areas of the neck, the muscles along the spine, and the upper trapezius; (2) sham group (n = 22): A low-level laser was irradiated with a passive probe (non-laser red light) in the affected areas of the neck, the muscles along the spine, and the upper trapezius. The treatment protocol consisted of 12 sessions (15 minutes, three times a week, for four weeks). These patients were evaluated for pain using the visual analog scale (VAS) (0-10). The patients were followed up for four weeks.

This study showed a statistically significant reduction in chronic nonspecific neck pain in the LLLT group (P < 0.05).

It is concluded that LLLT was effective in reducing chronic nonspecific neck pain. LLLT is a non-invasive, safe and effective method that can improve chronic nonspecific neck pain in patients in the short term.

Many studies have recognized the importance of new methods in wound healing. This study aims to investigate the healing effects of allograft extra embryonic mesenchymal stem cells (MSCs) with and without low-level diode laser irradiation when grafted into full-thickness skin defects in diabetic animal models.

In this experimental study, in order to make the rats diabetic, we used an intra-peritoneal injection of streptozotocin. Human amniotic membrane derived mesenchymal stem cells (hAMSCs) were irradiated with a low-level diode laser. Two full-thickness excisions were made on the backs of the rats. Next, the rats were divided into the following groups: group 1: low-level laser (LLL) irradiated hAMSCs and group 2: hAMSCs alone transplanted into skin wound. Histopathologic, ultrasound and elasticity evaluations were performed 7, 14 and 21 days after grafting.

In the evaluated rats, epithelial formation was on day 7 and increased until day 14. On days 7, 14 and 21, the percentage of epithelial formation in the irradiated cell group was significantly higher than that in the cell group, so that, on day 21, the epithelium in this group completely covered the wound surface while in the control group the wound surface was still not completely covered. In terms of angiogenesis, on day 7, the irradiated cells were significantly lower than the cells. Also, the formation of collagen in the cellular hydrogel group could confirm the effectiveness of amniotic MSCs in collagen production and thus accelerate the wound healing process. In comparison with hAMSCs alone, irradiated hAMSCs increased the thickness and elasticity of the skin.

Low-power laser along with MSCs can be effective in improving chronic wound condition in the animal model.

This research aimed to study the healing process of cryosurgical wounds after topical application of low-level laser and to evaluate its effects for the prevention of healing complications.

A total of 50 healthy male Wistar rats with an average weight of 200-250 g were selected and randomly divided into two main groups. In control group (N=25), cryosurgery was done without using of low-level laser. In experimental group (N=25), cryosurgery was done and the low-level laser was used for 10 days post-surgery. Each main group was divided into five subgroups (n=5) according to histopathological evaluation date (3, 7, 14, 21 and 28 days post-surgical) and healing process was evaluated on the wound specimens harvested at above-mentioned days. The full- thickness wounds were harvested in 40 mm in length and 20 mm in width and the specimens were stained using hematoxylin-eosin and Masson’s Trichrome staining. The healing process was evaluated and compared in groups by observation of granulation tissue and collagen fibers amounts, epithelial gap size, the number of inflammatory cells, and the rate of angiogenesis. Data were collected and statistically analyzed and compared between the experimental and control groups on specific days using the Kruskal-Wallis and Dan post hoc statistical tests.

The obtained data were compared between the experimental and control groups on different days using the Kruskal-Wallis and Dan post hoc statistical tests. The statistical results revealed significant differences between groups (P<0.05) in all mentioned variables. It revealed that the healing process in the experimental group took place at least one week earlier than the control group.

The results of this animal study showed that the low-level laser therapy on an experimental cryosurgical wound not only accelerates the healing process but also can be effective in the prevention of healing complications. The authors suggest further research to extend the results to human applications.

By considering the necessity prevention of hearing loss secondary to noise exposure, this research investigated the protective role of low-level laser (LLL) therapy in the prevention of cochlear outer hair cell (OHC) damage and death due to noise exposure in guinea-pigs.

In this study, a total of 30 male albino guinea-pigs (290±10 g) were used and randomly divided into three groups in order to evaluate hair cell counts and apoptosis of cochlear hair cells, including noise, control, and LLL therapy group each containing 10 pigs. The right outer ear canal of the LLL therapy group was exposed to165 mW/cm2 LLL for five successive days for just half an hour per day. Then, the LLL therapy and noise groups were exposed to 3-6 kHz octave band noise at 120 dBSPL. Twenty-one days after noise exposure, the animals of all groups were killed for the count of their OHCs and immunohistochemistry for caspase-3 experiments.

The percentage of OHCs in the base and middle turns of the cochlea was significantly lower in the noise group compared to the control and low laser therapy groups (P<0.05). The expression of caspase-3 significantly differed in the noise group in comparison to control and low laser groups regarding the experiment of immunohistochemistry (P<0.05).

The findings indicated that LLL was useful in the protection of the cochlear OHCs and could help in the prevention of hair-cell apoptosis.

Myofascial pain syndrome (MPS) is one of the most frequent causes of chronic musculoskeletal pain which is characterized by myofascial trigger points (MTrPs). Hence, it is of crucial importance to identify practical approaches for the treatment of these points. Upper trapezius muscle (UT) is highly susceptible to the development of MTrPs that are commonly resulted from overuse and micro-trauma.

The present study aimed to compare the effects of dry needling (DN) and low-level laser therapy (LLLT) regarding the reduction of pain and muscle thickness and improvement of the range of motion (ROM) and pressure pain threshold (PPT) in patients with latent MTrPs (LTrPs) in their UT muscles.

In total, 60 patients with LTrPs in UT muscle participated in this randomized clinical trial. The subjects were randomly divided into two treatment groups of DN and LLLT. The PPT was evaluatedby visual analog scale (VAS) and algometer while ROM and muscle thickness were assessed using goniometer and ultrasonography, respectively. It should be noted that the variables were evaluated before the first and after the sixth sessions. Finally, the collected data were analyzed using independent and paired t-tests.

Based on the results, the VAS and muscle thickness significantly reduced, while the PPT and cervical ROM increased in both groups after treatment (P<0.001). The independent t-test revealed a statistically significant improvement in the DN group in terms of PPT (9.9-14.17, P=0.009) and ROM (37.33-42.67, p=0.005), compared to the LLLTgroup. Nevertheless, no significant difference was found between the two groups regarding VAS and muscle thickness variables (P>0.05).

The DN and LLLT effectively improved symptoms in the UT muscles of patients with LTrPs. However, the DN was more effective in the improvement of ROM and PPT variables

ntroduction: The cytotoxicity of chemotherapy drugs is a significant challenge in the way of surmounting cancer. Liposomal drug delivery has proven to be efficacious in increasing the function of the drugs. Its potential to accumulate drugs in the target site and enhance the efficiency of anti-cancer agents with lower doses hinders their cytotoxicity on normal healthy cells. Since the release of drugs from liposomes is not generally on a controlled basis, several studies have suggested that external stimuli including lasers could be used to induce controlled release and boost the efficiency of liposomal drug delivery systems (LDDSs).

TheA375 cancer cell line was used and exposed to the liposomes containing doxorubicin in the presence of a low-level laser beam to investigate its effect on the liposomal stimuli-responsiveness release and its toxicity on cancer cells. So as to achieve that goal, Annexin V/PI was employed to analyze the number of cells that underwent apoptosis and necrosis.

Here, we report the effect of laser irradiation on LDDSs. According to the results obtained from the annexin V/PI assay, the pattern of viability status has shifted, so that the number of pre-apoptotic cells treated with liposomal doxorubicin and a laser beam was more than that of cells treated with only liposomal doxorubicin.

The use of stimuli-responsive LDDSs, in this case, laser-responsive, has led to favorable circumstances in the treatment of cancer, offering enhanced cancer cell cytotoxicity.

Erbium laser ablation as a method of tooth preparation and conditioning has shown promising results. Although previous studies have adopted various combinations of different laser parameters and several dentin adhesive systems, very few have investigated combining high-level and low-level ER:YAG lasers with Universal adhesives. This study aimed to assess the impact of using low-energy irradiation on the surface micro-topography and shear bond strength (SBS) of universal adhesive (UA) to the erbium:yttrium-aluminum-garnet (Er:YAG) laser-ablated dentin substrate, bonded in etch-and-rinse or self-etch adhesive mode.

Eighty-seven extracted molars were sectioned to expose flat occlusal dentin surface; 60 teeth were divided equally into three groups according to the surface treatment; bur-cutting (B), Er:YAG high-energy laser cutting (L1 - 200 mJ, 20 Hz, 50 μs pulse), or L1 followed by low-energy laser modification (L1/L2 - 80 mJ, 10 Hz, 50 μs pulse). Then each group was equally divided into two groups (n=10) according to the mode of application of the universal adhesive; either etch-and-rinse (ER) or self-etching (SE). The samples were subjected to thermocycling (5000 cycle between 5°C and 55°C), and SBS was tested. Two-way ANOVA and Tukey post hoc test were used to analyze the results. The remaining 27 samples were used to investigate the effect of the treatment on the topography of the treated dentin surfaces using a scanning electron microscope (SEM).

B/SE recorded the highest SBS (25.48 ± 2.6 MPa) followed by B/ER (23.20 ± 6.8 MPa) and L1/L2/SE (22.94 ± 4.1 MPa) and with no statistically significant difference between these groups (P>0.05). The lowest SBS results (P<0.05) were recorded for L1/SE (12.22 ± 3 MPa). No statistical differences were found between the SBS of L1/L2/ER and L1/ER groups or between the SBS of L1/L2/ER and L1/L2/SE groups.

A subsequent treatment of the Er:YAG laser-ablated dentin with low-energy laser modification mode (LMM) enhances the SBS of the tested UA when applied in SE mode.

Temporomandibular disorders (TMD) are one of the most prevalent disorders in maxillofacial area. Due to lack of understanding of the etiology or pathogenesis of TMD and a definitive  diagnostic or therapeutic approach, patients have to tolerate symptoms such as pain. This study was  aimed to perform a review of non-surgical treatment methods for TMD.

In this review, Google, Google Scholar, PubMed, SID, ISI Web of Science, SID and IranMedex databases were searched using key terms: temporomandibular  disorders, temporomandibular joint, temporomandibular pain, non-surgical treatment. Articles  meeting the inclusion criteria were recruited in the study. Finally, a total of 63 prospective  linical trials were evaluated from 2015 to 2020.

From the 61 studies evaluated, 27 studies were on low-level laser therapy (LLLT), 13 studies on transcutaneous electrical nerve stimulation (TENS), 5 studies on acupuncture and dry  needling, 1 study on laser acupuncture, 9 studies on platelet-rich plasma (PRP) and 6 studies on  Botox injection.

Laser acupuncture had similar treatment effects in reducing pain to TENS, low-level laser, acupuncture and dry needling. It seems that the use of laser acupuncture is safer than other methods in decreasing pain of patients with TMD.