laser therapy

Recent studies indicate that several factors are associated with different responses to pain relief and alteration in reactions to non-pharmacological modalities and pharmacological medications. Biological processes appear to be contributory factors to these outcomes.

The purpose of this study is to examine how laser therapy can help as a conservative approach for chronic pain after back surgery in patients with diabetes mellitus (DM).

This research included 22 diabetic patients and 26 non-diabetic patients with chronic pain after back surgery. Points of laser irradiation were determined by an ultrasound examination, specifically targeting bilateral sacroiliac joints, L2 - L3 through L5 - S1 facet joints, and the area of cluneal nerves. The duration of laser therapy was three weeks, with treatment sessions using an 808 nm diode laser at a power of 0.5W, performed every other day. Individuals were evaluated using the Oswestry Disability Index (ODI) and Numeric Rating Scale (NRS) before and after treatment, and again six months later.

Oswestry Disability Index and Numeric Rating Scale scores decreased significantly after treatment and six months later. Furthermore, analysis of the data showed that diabetic patients experienced less therapeutic effect during and after laser therapy sessions.

Although laser therapy can reduce pain, diabetic patients reported a lower level of effectiveness compared to non-diabetic patients.

 Laser therapy employs a concentrated and slender light beam to eliminate or eradicate cancerous cells and pre-cancerous abnormalities. The specific wavelength of 808 nm light is preferentially absorbed by tumor cells compared to healthy cells. This study aimed to assess the combined therapeutic impact of laser and gold, given that gold exhibits photothermal properties when exposed to laser radiation.

 In this in vitro study, two cell lines, namely healthy HuGu cells (human gingival fibroblast cells) and head and neck cancer cells (HN-5), were obtained from the Pasteur Institute. The effect of the laser diode with a density of 3 J/cm2 and wavelength of 808 nm on the proliferation and the survival rate of oral squamous cell carcinoma (HN-5) and human gingival fibroblast (HUGU) was assessed in 60seconds. MTT assay, DAPI test, and trypan blue staining were used to determine the growth and proliferation of HN-5 and HUGU cell lines.

 Findings showed that the laser diode along with gold decreased the rate of proliferation and survival cells in HN-5 compared to healthy cells. The changes in the cell population treated with gold and laser diode 808 were insignificant.

 Findings reveal that using a low-power laser can effectively inhibit the growth of oral cancer cells. It seems that photothermal therapy is a novel approach to oral cancer therapy.

 Unhealthy lifestyle choices such as alcohol, chemicals, and heat stress can worsen male infertility. Heat stress can cause damage to the essential structure known as the blood testis barrier (BTB). Photobiomodulation therapy (PBMT) has been employed in various studies to enhance sperm quality in individuals with genital inflammatory conditions in recent times. The current research sought to study how laser therapy affects spermatogenesis and the structure of the BTB in a mouse model of scrotal heat exposure.

 Thirty adult male NMRI mice, 8 weeks old, were divided into three groups: Control, Hyperthermia, and Hyperthermia+Laser 0.03 J/cm2. The animals in the hyperthermia group had their testicles exposed to water at 43 °C for 20 minutes five times every other day. Then, the testicles were exposed to laser radiation every other day for 35 days, lasting 3 minutes each time, with an energy density of 0.03 J/cm2. Animals were sacrificed, and sperm parameters, reactive oxygen species (ROS) and glutathione (GSH) levels, stereological parameters, and gene expression were assessed in the end.

 The study showed that PBMT could significantly enhance sperm quality, the quantity of spermatogenic cells, testicular volume, levels of ROS and GSH, and gene expression related to the blood testis barrier.

 Currently, PBMT is a novel approach to addressing male infertility by preserving the integrity of the BTB in Sertoli cells, which in turn supports the growth and specialization of germ cells.

This study explored the synergistic effects of low-level laser therapy (LLLT) and adipose-derived stem cells (ADSCs) on cranial bone regeneration in rats, addressing the limitations of autogenous grafts and advancing bone tissue engineering with innovative photobiomodulation (PBM) applications.

Sixty Wistar rats were allocated to 5 separate groups randomly; (1) natural bovine bone mineral (NBBM); (2) NBBM + LLLT; (3) NBBM + allogenic ADSCs; (4) NBBM + allogenic ADSCs + LLLT; (5) Only defects. 8-mm calvarial defects were made in each rat in the surgical procedure. A diode laser was applied with the following parameters (continuous mode, power of 100mW, wavelength of 808nm, and 4 J/cm2 energy density) immediately after the procedure and every other day. Bone samples were obtained and assessed histomorphometrically and histologically after staining with hematoxylin and eosin (H&E).

Different volumes of bony material were observed in two weeks; 2.94% ± 1.00 in group 1, 5.1% ± 1.92 in group 2, 7.11% ± 2.82 in group 3, 7.34% ± 2.31 in group 4, and 2.01% ± 0.83 in group 5 (P < 0.05). On the other hand, foreign body residuals were up by 23% in the groups with scaffolding by the end of 2 weeks. Four weeks of observation led to 6.74 % ± 1.95, 13.24% ± 1.98, 15.76% ± 1.19, 15.92% ± 3.4, and 3.11% ± 1.00 bone formation in groups 1 to 5, respectively (P < 0.05). Generally, the difference between groups 2-4 was not statistically significant based on different types of bone and the extent of inflammation.

Bearing in mind the limitations of our research, it was demonstrated that ADSCs in combination with PBM have promising effects on bone tissue regeneration in sizeable bony defects. Furthermore, this study also showed that PBM usage improved the newly regenerated bone quality.

 Trastuzumab is now increasingly being used as a potent HER2 inhibitor in treating breast cancer, while acneiform rashes sometimes arise as skin-related side effects in patients undergoing treatment with HER2 inhibitors, and their specificity as drug-induced eruptions makes their management quite challenging. Pulsed dye laser (PDL) therapy has been utilized to treat a wide variety of vascular lesions, achieving excellent outcomes.

Case Report: 

A 595 nm PDL was used to treat a 38-year-old woman suffering from an acneiform rash induced by trastuzumab as neoadjuvant therapy for breast cancer. One-half of the face received PDL treatment, while the other half served as the control.

 After just one PDL treatment, the skin lesion demonstrated a remarkable improvement, with a significant reduction in erythematous papules and inflammatory pustules, as well as an improvement in skin thickening. PDL therapy might offer an effective alternative for managing acneiform rashes induced by trastuzumab.

Candida albicans is the primary pathogen responsible for oral candidiasis. The emerging resistance of fungi to antifungal agents has led to the development of new fungicidal treatments.

This study aimed to analyze the effects of 660, 810, and 940 nm laser wavelengths on nystatin-resistant C. albicans .

In this in vitro study, a standard strain of C. albicans and eight nystatin-resistant isolates were irradiated with 660, 810, and 940 nm diode lasers for 40 and 80 seconds (s) and compared with nystatin. Colony numbers and nystatin susceptibility were evaluated using the minimum inhibitory concentration (MIC).

All laser wavelengths significantly decreased the colony count of the standard strain of C. albicans , with 40s of 810 nm laser irradiation causing the maximum reduction in colony count (P810 nm < 0.001). Similarly, all laser wavelengths significantly reduced the colony count of nystatin-resistant isolates, and they were more effective than nystatin (unlike with the standard strain) (P < 0.05). The 810 nm laser irradiation for 40s demonstrated the greatest effect on MIC among the laser groups.

The 810 nm laser for 40s was the most effective in reducing the colony count of nystatin-resistant C. albicans , and it eliminated resistance in all clinical isolates.

This study aims to compare previous studies using lasers to evaluate the efficacy and safety of laser therapy adjacent to traditional methods. PubMed and Cochrane search engines were used to identify previous studies of laser assisted periodontal therapy. 29 articles were selected after applying specific keywords, additional filters, inclusion and exclusion criteria between the years 2018 and 2024 out of 107,255 articles. The results have indicated the efficacy of Nd:YAG, diode and CO2 laser for frenectomy.A single study using Er:YAG showed a decrease in operation and bleeding time. Er:YAG, Er, Cr:YSGG and diode have shown an efficacy for second-stage surgery of submerged implants. 2780 nm Er,Cr:YSGG used for crown lengthening surgery have shown a stable height increase after surgery unlike the conventional group. Nd;YAG showed a significant difference while Er,Cr:YSGG haven’t in gingivectomy and osteotomy. Significant improved healing was shown using a ER:YAG and 660,940 and 980 nm diode for regenerative surgical therapy. Laser techniques using a 2940 nm Er:YAG and 980 nm Diode laser were efficient for gingival depigmentation. 1064 nm Nd:YAG showed a significant difference while 810 nm diode, PDT and Er:YAG laser haven’t in comparison with the traditional method in reduction of bacteria. Studies reported a significant reduction in the average dental pain range using 808, 940, 980 nm diode and 2780 nm Er,Cr:YSGG laser. laser assisted treatments in variety of peridontal therapies was efficient and safe considering the wavelength and type of laser for each therapy

We recently have read with great interest an article entitled “Comparison of High-intensity Laser Therapy with Extracorporeal Shock Wave Therapy in the Treatment of Patients with Plantar Fasciitis: A Double-blind Randomized Clinical Trial”, by Zare Bidoki and colleagues, which was published in your esteemed journal (IJMS Volume 49, Issue 3, March 2024).

 Scaling and root planing (SRP) is an inevitable primary step in non-surgical periodontal therapy. Debridement carried out with manual instruments and ultrasonics results in the removal of tooth structure. Current research revolves around laser as an efficient adjunct to SRP. This study evaluated and compared the effectiveness of root surface calculus removal between ultrasonics and Er,Cr:YSGG laser.

 Twenty-eight single-rooted teeth extracted due to periodontal disease were selected for the study. The specimens were randomly assigned to two groups (n=14). Group I underwent ultrasonic instrumentation using a piezo ultrasonic scaler, and group II was subjected to laser instrumentation using Er,Cr:YSGG laser (Waterlase). The specimens were processed, fixed, viewed under a field emission scanning electron microscope and evaluated using the remaining calculus index (RCI) and loss of tooth substance index (LTSI).

 Ultrasonics-treated specimens revealed more remaining calculus (1.57±0.65) and lost tooth substance (1.71±0.61) compared to the Er,Cr:YSGG laser-treated specimens, with significantly lower RCI (0.71±0.61) and LTSI (1.00±0.56). There was a statistically significant difference (P<0.05) in the efficacy of root surface calculus removal between the two groups.

 Compared to ultrasonics, Er,Cr:YSGG laser demonstrated superior results by causing precise removal of root surface calculus without significantly affecting tooth structure and aiding in new attachment.

One of the causes of infertility is azoospermia. The present study aimed to investigate the effects of swimming exercise, cell therapy, and laser therapy on the expression of genes involved in mitochondrial dynamics in the testicular tissue of azoospermic rats.

In this experimental study, 40 rats (6-8-weeks old) were randomly assigned to 8 groups: 1) Healthy control, 2) patient, 3) sham, 4) laser, 5) exercise, 6) cell, 7) cell + laser, and 8) cell + exercise. The azoospermia model was induced using busulfan at a dose of 40 mg. Stem cells were transplanted once into the vas deferens at a concentration of 1000000 cells per rat. One week after cell transplantation, laser therapy was applied in three repetitions throughout the study period, with an interval of once a week, and after wound healing, the rats swam for 30 minutes a day, 5 days a week, for 8 weeks. To investigate the expression of the studied genes, tissue analysis was performed by the real-time polymerase chain reaction (RT-PCR) technique.

Azoospermia significantly reduced the expression of mitofusin 2 (Mfn2) and significantly increased the expression of dynamin-related protein 1 (Drp1) and muscle-specific RING finger protein 1 (Murf1) in testicular tissue. The use of interventional methods increased the expression of Mfn2, and significantly reduced the expression of Murf1.

Based on the findings, the best changes were observed in the exercise + laser group. Therefore, it can be said that in rats using the azoospermia model, the simultaneous use of regular exercise interventions and laser therapy is the most effective.

The frequency of recurrence is a critical factor in the utilization of different treatments for pterygium. The present study was undertaken to compare the pterygium recurrence rates after bare sclera excision with that of argon laser therapy.

Sixty eyes of 53 patients with primary pterygium were included in this prospective, interventional case series. The participants were randomly categorized into 2 groups each consisting of 30 subjects. In the first group, pterygium excision was performed using bare sclera technique whereas the second group received argon laser therapy alone. The patients were examined for pterygium recurrence and complications at postoperative 1 and 7 days as well as in months 1, 3, and 6 after the operation. All analyses were performed using SPSS software (version 17.0) and P-values less than 0.05 were considered significant.

Pterygia recurred in 7 eyes (23.3 %) in the first group (i.e. bare sclera group) and in 4 eyes (13.3 %) in the second group (i.e. argon laser therapy group). The recurrence rate was not significantly different between the two groups. No ocular or systemic complication developed till the end of follow-up.

 Argon laser photocoagulation of pterygium may be more favorable for patients with coagulopathy or a history of conjunctival surgery. The coagulation effect of the argon laser may prevent severe conjunctival bleeding, which may occur after surgical excision in patients with coagulopathy.

 High power laser therapy (HPLT) seems to be a new modality to possibly manage rotator cuff tendinitis.The purpose of this study was to investigate the effects of HPLT on clinical and sonographic findings in people with chronic rotator cuff tendinitis.

 Thirty-two people suffering from rotator cuff tendinitis participated in this study. The patients  were  randomly assigned to the control group (n=16) that received routine physiotherapy including Transcutaneous electrical nerve stimulation (TENS), ultrasound, hot pack, exercise consisting range of motion, pendulum, strengthening, and stability exercises, or the treatment group (n=16) that received routine physiotherapy and HPLT in the painful area of the shoulder (12 sessions) Clinical and functional findings including pain, shoulder range of motion, shoulder disability, and sub-acromial liquid were measured using the visual analog scale, goniometry, questionnaire, and sonography, respectively before and after treatment.

 Pain, active and passive range of motion, shoulder disability and sub-acromial fluid accumulation were significantly different in both groups and improved, but no difference was reported in the thickness of the rotator cuff tendon, especially the supraspinatus tendon. The improvement was more significant (pain reduction and sub-acromial liquid, increase in range of motion and level of function) in the treatment group than in the control group (P <0.05).

 HPLT combined with the routine physiotherapy improve the clinical as well as sonography findings including supraspinatus tendon thickness and accumulation of sub-acromial fluid in people with rotator cuff tendinitis compared with those in the control group.

The most common cause of heel pain is plantar fasciitis (PF). Although conservative treatments relieve pain in more than 90% of patients, it may remain painful in some cases. This study aimed to compare High-intensity Laser Therapy (HILT) with Extracorporeal Shock Wave Therapy (ESWT) in patients with PF.

In this double-blinded randomized clinical trial (conducted in Yazd, Iran, from May 2020 to March 2021), patients were classified into two groups, including the ESWT and HILT, using online randomization. Nine sessions, three times a week for 3 weeks, were the treatment period in both groups. Visual Analogue Score (VAS), Heel Tenderness Index (HTI), and the SF36 questionnaire were compared and analyzed statistically at the beginning and 9 months after treatment. 

38 patients (19 in each group) completed the study. Results showed that pain and patient satisfaction improved significantly 3 months after treatment. The VAS and HTI decreased 3 months after treatment in both groups, which was statistically significant (P<0.001). The SF36 score in both groups increased 3 months after treatment, and this increase was statistically significant (P<0.001). Although the two modalities were effective based on VAS, HTI, and SF36, a significant statistical difference was observed between them (P=0.03, P=0.006, P=0.002, respectively), and the HILT was more effective.

ESWT and HILT decrease pain and increase patient satisfaction in PF. Besides, both methods are non-invasive and safe. However, there is a significant difference between them, and HILT is more effective.Trial registration number: IRCT20210913052465N1.

Statement of the Problem:

 Trigeminal neuralgia is the most common and disabling type of neuralgia in craniofacial region. Because of adverse effects of first and second lines of treatment, new modalities including laser therapy have been investigated for treatment of trigeminal neuralgia.

The aim of this study was to review the effect of laser in trigeminal neuralgia. PubMed, Scopus, Web of Science, Science Direct and Embase databases from December 1983 to August 2020 were searched using keywords “trigeminal neuralgia” and “laser”. Our inclusion criteria were interventional studies with a randomized clinical trial design, which used laser for treatment of trigeminal neuralgia.

A total of 269 records were identified through systematically searching aforementioned databases among which, 30 were from PubMed and 44 were from Web of Science. A total of 111 records were duplicated and were therefore removed.

Only 17 records were considered relevant after reading title and abstracts. After reading full texts of the articles, 13 met the eligibility criteria and were included in our review.

This review revealed that low-level laser therapy reduces pain in trigeminal neuralgia specially diode lasers, although there are no standardized protocols for laser procedures.

The aim of this paper was to provide a comprehensive review of using low-level laser therapy (LLLT) as a therapeutic method for recurrent aphthous stomatitis (RAS), including analyzing its underlying mechanisms, clinical applications, and potential benefits.

A database search was conducted to identify relevant papers investigating the use of LLLT for RAS treatment. Articles published in scientific journals and selected for review in Science Direct, Google Scholar, and PubMed were categorized and analyzed.

During the initial search, a total of 88 articles were found. Five phases were performed to select articles, and eventually, 8 papers that met the inclusion criteria were chosen.

This literature review supports the idea that LLLT is a non-invasive and potentially effective therapy for RAS symptoms by accelerating the healing process and having beneficial effects in reducing pain and inflammation.

 Fibroblasts are the most important cells in the healing process of wounds. The motility activity of low-level laser (light) therapy (LLLT) on fibroblast proliferation has been well-established in vitro. Laser treatment for scar removal increases the number of scars.

 This method uses light therapy to remove the outer layer of the skin surface and produce new skin cells to cover the damaged skin cells.

 The present research is from an experimental laboratory. First, tissue fibroblast cells were cultured under appropriate conditions. Then, it was exposed to laser radiation with intensities of 650 and 980 nm, and its supernatant solution was used for wound treatment. Interleukin 2 (IL-2), tumor necrosis factor-α (TNF-α), and vascular endothelial growth factor (VEGF) levels were used to check the recovery.

 The results of the MTT assay showed an increase in the viability of the cell line under laser irradiation. In addition, these evaluations showed an increase in IL-2, TNF-α, and VEGF after 650 and 980 nm laser irradiation compared to the control group after 48 hours.

 According to the present study, laser therapy has potential therapeutic potential for wound healing. However, more studies are suggested to increase the efficiency and speed up the treatment process.