The effect of He-Ne and Ga-Al-As laser light on the healing of hard palate mucosa of mice

NIR Laser Irradiation Promotes Osteogenic Differentiation of PDLSCs Through the Activation of TRPV1 Channels and Subsequent Calcium Signaling

Near-infrared (NIR) irradiation has shown potential to stimulate osteogenic differentiation, but the mechanisms are not fully understood. The study is to investigate the effects of NIR laser irradiation on osteoblastic differentiation. Human periodontal ligament stem cells (hPDLSCs) were cultured in osteogenic medium and exposed to 810 nm NIR laser at 0.5 J/cm2 every 48 h. The transient receptor potential vanilloid (TRPV1) channel inhibitor capsazepine (CPZ) was used to evaluate the role of calcium influx. Osteogenic differentiation was assessed by proliferation (CCK-8), alkaline phosphatase (ALP) activity, mineralization (Alizarin Red), and expression of bone markers by PCR and Western blot over 2 weeks. Intracellular calcium was measured by Fluo-4M dye and flow cytometry. Results showed that NIR irradiation enhanced hPDLSC proliferation, ALP activity, mineralization, and bone marker expression, indicating increased osteogenic differentiation. These effects were inhibited by CPZ. NIR induced a transient rise in intracellular calcium peaking at 3 min, which was blocked by CPZ. In conclusion, this study demonstrates that NIR laser irradiation promotes osteogenic differentiation of PDLSCs through the activation of TRPV1 channels and subsequent calcium signaling. Further research is warranted to optimize the treatment parameters and elucidate the detailed signaling pathways involved, paving the way for the clinical application of NIR therapy in the treatment of bone disorders and periodontal disease.

Wound healing after therapy of oral potentially malignant disorders with a 445-nm semiconductor laser: a randomized clinical trial

OBJECTIVES

Oral potentially malignant disorders (OPMDs) are the most clinically relevant precursor lesions of the oral squamous cell carcinoma (OSCC). OSCC is one of the 15 most common cancers worldwide. OSCC is with its high rate of mortality an important cause of death worldwide. The diagnosis and therapy of clinically relevant precursor lesions of the OSCC is one of the main parts of prevention of this malignant disease. Targeted therapy is one of the main challenges concerning an oncologically safe tissue removal without overwhelming functional and aesthetic impairment.

MATERIALS AND METHODS

In this randomized controlled trial, a newly introduced intraoral 445-nm semiconductor laser (2W; cw-mode; SIROLaser Blue, Dentsply Sirona, Bensheim, Germany) was used in the therapy of OPMDs. Duration and course of wound healing, pain, and scar tissue formation were compared to classical cold blade removal with primary suture by measuring remaining wound area, tissue colorimetry, and visual analogue scale. The study includes 40 patients randomized using a random spreadsheet sequence in two groups (n1 = 20; n2 = 20).

RESULTS

This comparative analysis revealed a significantly reduced remaining wound area after 1, 2, and 4 weeks in the laser group compared to the cold blade group (p < 0.05). In the laser group, a significantly reduced postoperative pain after 1 week was measured (p < 0.05).

CONCLUSION

Laser coagulation of OPMDs with the investigated 445-nm semiconductor laser is a safe, gentle, and predictable surgical procedure with beneficial wound healing and reduced postoperative discomfort.

CLINICAL RELEVANCE

Compared to the more invasive and bloody cold blade removal with scalpel, the 445-nm semiconductor laser could be a new functional less traumatic tool in the therapy of OPMDs. The method should be further investigated with regard to the identification of further possible indications.

TRAIL REGISTRATION

German Clinical Trials Register No: DRKS00032626.

The Mechanisms and Efficacy of Photobiomodulation Therapy for Arthritis: A Comprehensive Review

Rheumatoid arthritis (RA) and osteoarthritis (OA) have a significant impact on the quality of life of patients around the world, causing significant pain and disability. Furthermore, the drugs used to treat these conditions frequently have side effects that add to the patient's burden. Photobiomodulation (PBM) has emerged as a promising treatment approach in recent years. PBM effectively reduces inflammation by utilizing near-infrared light emitted by lasers or LEDs. In contrast to photothermal effects, PBM causes a photobiological response in cells, which regulates their functional response to light and reduces inflammation. PBM's anti-inflammatory properties and beneficial effects in arthritis treatment have been reported in numerous studies, including animal experiments and clinical trials. PBM's effectiveness in arthritis treatment has been extensively researched in arthritis-specific cells. Despite the positive results of PBM treatment, questions about specific parameters such as wavelength, dose, power density, irradiation time, and treatment site remain. The goal of this comprehensive review is to systematically summarize the mechanisms of PBM in arthritis treatment, the development of animal arthritis models, and the anti-inflammatory and joint function recovery effects seen in these models. The review also goes over the evaluation methods used in clinical trials. Overall, this review provides valuable insights for researchers investigating PBM treatment for arthritis, providing important references for parameters, model techniques, and evaluation methods in future studies.

Diode laser in management of loss of taste sensation in patients with post-COVID syndrome: a randomized clinical trial

OBJECTIVE

Loss of taste (ageusia) is a symptom observed following recovery from COVID-19 infection. The loss of taste and smell sensation may negatively affect patients' quality of life (QoL). The present study aimed to evaluate the effectiveness of the Diode Laser in managing loss of taste sensation in patients with post-COVID syndrome versus the placebo.

MATERIAL AND METHOD

The study sample was 36 patients who complained of persistent loss of taste sensation following COVID-19. The patients were randomly assigned to one of the two groups according to the received treatment: Group I (laser treatment) and Group II (light treatment), with each patient receiving a diode laser treatment or placebo from the same operator. Taste sensation was subjectively measured after treatment for four weeks.

RESULTS

The results demonstrated a significant difference between both groups regarding taste restoration after one month (p = 0.041), with Group II having a significantly higher percentage of cases 7 (38.9%) with partial taste restoration. In contrast, a significantly higher proportion of Group I 17 cases (94.4%) had complete taste restoration (p < 0.001).

CONCLUSION

The present study concluded that using a Diode laser 810 nm aided in a more rapid recovery from loss of taste dysfunction.

Evaluation of low-level laser therapy and platelet-rich fibrin on donor site healing after vascularized interpositional periosteal connective tissue flap: a randomized clinical study

AIM

To evaluate the effectiveness of platelet-rich fibrin (PRF) and low-level laser therapy (LLLT) on donor site healing after vascularized interpositional periosteal connective tissue (VIP-CT) flap.

MATERIALS AND METHODS

For the present clinical study, the selected patients requiring VIP-CT flap were randomly assigned into either of the two treatment groups (VIP-CT/PRF and VIP-CT/LLLT). For VIP-CT/PRF, palatal donor site treated with platelet-rich fibrin (PRF, n = 15) after harvesting VIP-CT flap; and for VIP-CT/LLLT, palatal donor site treated with low-level laser therapy (LLLT, n = 16) after harvesting VIP-CT flap.

RESULTS

The mean thickness of palatal mucosa at surgical site was increased from 2.91 ± 0.65 to 2.93 ± 0.55 mm after 1 week and to 3.02 ± 0.55 mm after 12 weeks while in PRF-treated site, while in LLLT-treated sites, palatal mucosal thickness decreased after 1 week from 3.35 ± 0.56 mm to 1.83 ± 0.48 mm and then increase to 3.35 ± 0.55 mm after 12 weeks, and the mean difference was significantly higher for PRF-treated group compared to LLLT-treated group. In regard to contour, absence of hypertrophic tissue was observed in VIP-CT/LLLT compared with VIP-CT/PRF group (40% of patients, p = 0.003) at 4 weeks. "Absence" of pain and burning sensation were observed as early as at 1 week in LLLT-treated palatal donor sites compared to PRF-treated palatal donor site after VIP-CT. Improvement in post-surgical complications like ecchymosis, tissue necrosis, swelling, and infection were observed almost 100% at 4 weeks in both the groups.

CONCLUSION

Favourable clinical outcomes in terms of tissue thickness, consistency, color, contour, scar, pain, and burning sensation and patient comfort were obtained in both LLLT- and PRF-treated donor palatal sites at 12 weeks. Non-significant increase in tissue thickness was observed compared to baseline in PRF-treated donor sites at 12 weeks compared to LLLT-treated donor sites.

CLINICAL SIGNIFICANCE

Both low-level laser therapy (LLLT) using 940 nm wavelength and autologous platelet-rich fibrin (PRF) can be utilized to enhance early wound healing and reduce the palatal donor site morbidity.

Lichenoid drug eruption on the lower lip caused by anti-PD-1 monoclonal antibody: a case report and literature review

Anti-PD-1/PD-L1 monoclonal antibodies result in a unique spectrum of side effects, widely known as immune-related adverse events. Toripalimab is an anti-PD-1 monoclonal antibody used for the treatment of some cancers. Here we report the first case, to our knowledge, of oral lichenoid drug reaction triggered by toripalimab. A 78-year-old man who was diagnosed with systemic metastatic prostate cancer presented with ulcers on the lower lip after the fifth cycle of toripalimab. We diagnosed him with oral lichenoid drug reaction based on clinical manifestation, histopathological findings and the history of anti-PD-1 therapy. The patient responded well to oral corticosteroids combined with helium-neon laser therapy. The anti-PD-1 therapy was not restarted because of stable disease, and the eruptions did not recur.

Laterally closed tunnel technique with and without adjunctive photobiomodulation therapy for the management of isolated gingival recession-a randomized controlled assessor-blinded clinical trial

The objective of this prospective randomized controlled single-center clinical trial was to prove the efficacy of adjunctive photobiomodulation in improving selected outcomes following the use of laterally closed tunnel technique for the management of isolated gingival recession. Nineteen participants (with isolated gingival recession) each treated by laterally closed tunnel technique were randomized to either add on treatment with control (sham laser application) or test group (photobiomodulation with 660 nm diode, 3.5 J/cm² per point of application). The primary outcome variable was change in recession depth and secondary variables included recession width, width of keratinized gingiva, periodontal biotype, and VAS score for pain assessment and EHS index for early wound healing assessment. Analysis was performed using a linear mixed effects model. There were no significant differences in the gingival recession depth (p = 0.8324) and recession width (p-0.969) at 3-month follow-up. The VAS scores were significantly lower for the test (laterally closed tunnel technique + photobiomodulation) group as compared to control (laterally closed tunnel technique + sham laser) over time (p =  < 0.0001) as well as per site (p = 0.0006) The Early Wound Healing Index scores were significantly higher in the test (laterally closed tunnel technique + photobiomodulation) group as compared to control (laterally closed tunnel technique + sham laser) group (p < 0.0001). The adjunctive use of photobiomodulation did not show a better outcome concerning recession depth but appears to provide faster healing of the surgical wounds and better patient comfort. The result needs further evaluation in particular with respect to long-term effect and due to limitation in sample size. Clinical Trial Registry of India: CTRI/2019/11/022012.

Ultrasonographic evaluation of the titanium-prepared platelet-rich fibrin effect in free gingival graft procedures

BACKGROUND

Complications after free gingival graft (FGG) operations are generally related to the donor site. The titanium-prepared, platelet-rich fibrin (T-PRF) placement in the donor site accelerate the wound healing and prevent postoperative complications such as pain and hemorrhage. We aim to evaluate the effect of T-PRF regarding vascularization and tissue thickness and to report the advantages of the ultrasonography (US) in FGG.

METHODS

Ten individuals were divided into two groups as T-PRF and control. While the T-PRF membrane was placed at the donor site in the T-PRF group, a gelatin sponge was placed in the control group. All patients underwent US examination in terms of vascularization and tissue thickness of left and right donor sites. The correlation between the right and left donor sites was analyzed with the Pearson correlation test. Tissue thicknesses and pulsatility index (PI) were analyzed with independent samples t-test. The results were evaluated statistically at the P <0.05 significance level.

RESULTS

The T-PRF group showed increased vascularity which can be interpreted to improve healing in soft tissue. However, not a difference, but a positively very high correlation was observed between the right and left tissue thicknesses (P = 0,00; r = +0902).

CONCLUSIONS

Evaluation of tissue thickness and vascularization density of donor sites with US not only increases clinical success rate but also reduces the risk of complications during surgery and postoperative pain in FGG. Studies evaluating T-PRF membrane as palatal dressing after FGG are only clinical, however, the efficiency of T-PRF was evaluated radiologically in this study for the first time.

The inflammation and reactive oxygen species regulated by Nrf2 and NF-κB signaling pathways in 630-nm light-emitting diode irradiation treated THP-1 monocytes/macrophages

Because of a large number of macrophages and its secreted pro-inflammatory factors in the synovial fluid of patients with rheumatoid arthritis, the present study aimed to investigate the effect and mechanism of 630-nm LED exposure on monocytes/macrophages and its anti-inflammatory effect. The THP-1 monocytes and PMA-induced THP-1 macrophages (THP-1 macrophages) were employed and irradiated by 630-nm LED for different time and times, and then measure the pro-inflammatory cytokines production by RT-qPCR and Milliplex MAP Multiplex assay, the proteins involved in inflammation pathway and reactive oxygen species (ROS) levels in the cells were detected by Western blot and DCFH-DA method. The exposure dose of red LED (15.3 J/cm², 30.6 J/cm²) were determined as no-influence on the cell proliferation, the pro-inflammatory factors TNF-α and IL-1β mRNAs, and secretions in supernatant of THP-1 macrophages were significantly decreased after LED exposure. The ROS production was blocked in THP-1 monocytes and THP-1 macrophages after treatment of LED. Finally, the phosphorylated NF-κB proteins which involved in inflammation pathway significantly decreased, and its inhibitors Nrf2 were slightly upregulated. The effects of LED anti-inflammation response are dependent on the mechanism of inhibiting ROS level and regulating NF-κB signaling pathways by increasing Nrf2 expression in the cells. It is suggested that 630-nm LED could decrease pro-inflammation in immune cells, and it may be a beneficial adjunct therapy in relieving inflammation of patients with rheumatoid arthritis.

Effects of Different Protocols of Low-Level Laser Therapy on Collagen Deposition in Wound Healing

The low-level laser has proven successful in stimulating the production of collagen in wound healing assays. However, diversity has been observed in the protocols used. This work has evaluated the effects of three protocols of low-level laser therapy (LLLT) in the healing of open wounds in rats. Standard-sized wounds of 1 cm2 were performed with a scalpel in the middorsal region of 60 male Wistar rats weighing 225±25 g, and they were assigned into four groups (n=15): CTR (non-irradiated animals), LT1 (20 J/cm2 daily), LT2 (16 J/cm2 daily) and LT3 (20 J/cm2 daily). After 7, 14 and 21 days, five animals/day were euthanized and the wounds analyzed histologically. Data were subjected to normality analysis of distribution using Shapiro-Wilk test. Gaussian data were analyzed using ANOVA and Bonferroni tests whereas non-Gaussian data were analyzed using Kruskal-Wallis and Dunn tests, considering significant p values less than 0.05. The LLLT in all protocols reduced the inflammation and collagen deposition increased significantly (p<0.05). However, LT2 showed the highest levels of collagen in all phases of the study (p<0.05) induced faster replacement of immature collagen III by mature collagen I in the early stages of repair and early collagen remodeling promoted by providing better organization architectural beams deposited. It was concluded that all protocols induced an increase in collagen scar. However, the protocol 2 (16 J /cm2, daily application) promoted the most significant increases in collagen deposition, accelerated maturation of collagen and showed the best architecture of the final fibrous scarring.

Evaluating the Effects of a Topical Preparation with Dexpanthenol, Silbiol, Undecylenic Acid, and Lidocaine on Palatal Mucosa Wound Healing in a Rat Model

Background

Postoperative complications occur after periodontal plastic surgeries, but an ideal treatment to overcome them has not been found yet.

Aims

To evaluate the effects of topically applied Oral-norm gel on the healing of excisional wounds.

Study Design

Animal experiment.

Methods

Excisional wounds with a diameter of 3 mm were made in the center of the palatal mucosa of 63 Sprague Dawley rats. Seven animals were sacrificed at time 0. The remaining rats were divided into two groups: a test group in which the topical Oral-norm gel was applied three times a day and a control group in which nothing was applied. Seven animals in each group were sacrificed at 3, 7, 14, and 21 days. Mean wound surface area was measured photographically, while wound healing and width were evaluated microscopically.

Results

The mean wound surface area decreased significantly after 3 days in both groups (p<0.001). Between days 3 and 7, the mean wound surface area decreased from 6.62 (2.85) to 0.83 (1.62) mm² in the control group and 5.07 (0.88) to 1.42 (1.67) mm² in the test group. The wound width decreased significantly on day 7 in both groups (p<0.001), with no further changes by day 14. Both groups had a significant increase in inflammation and vascularization on day 3 (p<0.001), with a reduction thereafter. No significant differences in macroscopic and microscopic measurements were observed between the groups at any time point (p>0.05).

Conclusion

The Oral-norm gel has no positive healing effects in the palatal mucosa of rats.

Improving Would Healing Ability by Training: Experiences of China

In China, chronic wounds are an important issue. However, wound care knowledge and the skill of health care professionals varies among hospitals and cities. A training program in wound care in China was completed in 2015 and achieved great success. To facilitate expertise in wound healing in China, a sequential training project supported by the Wound Healing Union and the Chinese Medical Doctor Association was initiated. The aim of the training program was mainly to improve experience and skills in wound healing. Until December 2016, a total of 301 medical staffs, including 134 physicians and 167 nurses, have been trained. Most of the doctors (92 of 134) and nurses (142 of 167) were from Grade IIIA/B hospitals, and there were no doctors and nurses from community hospitals. Most participants were satisfied about the training program, and more nurses were satisfied (79%) than doctors (60%). All trainees have completed 4½ months of training and passed a final examination.

Biochemical changes induced by grape seed extract and low level laser therapy administration during intraoral wound healing in rat liver: an experimental and in silico study

In the present study, the changes that occur in rat liver tissue as a result of the use of grape seed extract (GSE) and low level laser therapy (LLLT) in intraoral wound (IW) healing are analyzed using biochemical parameters. Diode laser application groups received 8 J/cm2 dose LLLT once a day for 4 days (810 nm wavelength, continuous mode, 0.25 W, 9 s). As a result of the biological parameter analysis, it was determined that the oxidative damage caused by the IWs and recovery period on 7th and 14th days could be substantially removed with GSE applications that have antioxidant capacity especially in rat liver tissue. In addition, the active compound of grape seed, catechin is studied in the active site of glycogen synthase kinase 3 (GSK3) target using molecular modeling approaches. Post-processing molecular dynamics (MD) results for catechin is compared with a standard GSK3 inhibitor. MD simulations assisted for better understanding of inhibition mechanism and the crucial amino acids contributing in the ligand binding. These results along with a through free energy analysis of ligands using sophisticated simulations methods are quite striking and it suggests a greater future role for simulation in deciphering complex patterns of molecular mechanism in combination with methods for understanding drug-receptor interactions.

Low-Level Laser Therapy in Enhancing Wound Healing and Preserving Tissue Thickness at Free Gingival Graft Donor Sites: A Randomized, Controlled Clinical Study

OBJECTIVE

The aim of this study was to determine the effects of low-level laser therapy (LLLT) on wound healing at free gingival graft (FGG) donor sites.

MATERIALS AND METHODS

Forty patients requiring FGG were selected for this randomized, controlled, and double-blinded prospective clinical trial. The FGG donor sites were treated with LLLT and compared with an untreated control group. The Wound-Healing Index (WHI), tissue consistency, color match, and H₂O₂ bubbling test for the evaluation of complete wound epithelialization were recorded on the 3rd, 7th, 14th and 21st days. The pain-burning level, number of analgesics, and bleeding were recorded for 7 days. Donor area soft tissue thickness (TT) was measured at baseline and at the first month.

RESULTS

The prevalence of Complete Wound Epithelization was higher in the LLLT group than in the control group on the 14th day (p < 0.001). The bleeding was lower in the test group than in the control group during the first 2 days (p ≤ 0.001). Higher WHI Scores were observed in the test group relative to the control group at all visits (p ≤ 0.001). Color match scores were higher in the test group than in the control group at the first 3 visits (p < 0.05). The TT changed from 4.62 ± 0.79 to 4.71 ± 0.82 mm in the LLLT group and from 4.23 ± 0.62 to 4.01 ± 0.68 mm in the control group.

CONCLUSIONS

It can be concluded that LLLT enhances FGG donor site wound healing and preserves TT at palatinal donor sites.

The role of titanium-prepared platelet-rich fibrin in palatal mucosal wound healing and histoconduction

OBJECTIVE

We aimed to determine the clinical effects of titanium-prepared, platelet-rich fibrin (T-PRF) on human palatal mucosal wound healing (PMWH) and to identify its effect on time-dependent changes in palatal soft-tissue thickness (PSTT) in terms of histoconduction, which is a new concept.

MATERIALS AND METHODS

Free gingival graft (FGG) donor sites were treated with T-PRF and compared with an untreated control group. The results of colour match and H₂O₂-bubbling tests for complete wound epithelization (CWE) were recorded on days 3, 7, 14 and 21. Pain level, number of analgesics used and bleeding status were recorded for the first 7 days. PSTT was measured at baseline and after 1 and 6 months.

RESULTS

Colour match scores of the test group were significantly higher than those of the control group at 7 and 14 days. CWE was observed at a higher frequency in the test group than in the control group on day 14. Post-operative bleeding prevalence was lower in the test group than in the control group for the first 2 days. A time-dependent decrease in PSTT was observed at 1 and 6 months in the control group compared with baseline (baseline, 4.23 ± 0.62 mm; 1 month, 4.01 ± 0.68 mm; and 6 months, 3.93 ± 0.69 mm). However, no significant difference was found in the test group (baseline, 4.29 ± 0.64 mm; 1 month, 4.61 ± 0.51 mm; and 6 months, 4.51 ± 0.58 mm).

CONCLUSION

The T-PRF membrane exhibited positive effects on PMWH. T-PRF, which is a promising autogenous matrix for histoconduction, may also be preferred as an autogenous alternative to connective tissue grafts in the treatment of gingival recessions and peri-implant mucosal recessions.

Effects of a Low-Intensity Laser on Dental Implant Osseointegration: Removal Torque and Resonance Frequency Analysis in Rabbits

The objective of this study was to investigate how a low-intensity laser affects the stability and reverse torque resistance of dental implants installed in the tibia of rabbits. Thirty rabbits received 60 dental implants with the same design and surface treatment, one in each proximal metaphysis of the tibia. Three groups were prepared (n = 10 animals each): conventional osseointegration without treatment (control group), surgical sites irradiated with a laser beam emitted in the visible range of 680 nm (Lg1 group), surgical sites irradiated with a laser beam with a wavelength in the infrared range of 830 nm (Lg2 group). Ten irradiation sessions were performed 48 hours apart; the first session was during the immediate postoperative period. Irradiation energy density was 4 J/cm2 per point in 2 points on each side of the tibias. The resonance frequency and removal torque values were measured at 2 time points after the implantations (3 and 6 weeks). Both laser groups (Lg1 and Lg2) presented a significant difference between resonance frequency analysis values at the baseline and the values obtained after 3 and 6 weeks (P &gt; .05). Although the removal torque values of all groups increased after 6 weeks (P &lt; .05), both laser groups presented greater mean values than those of the control group (P &lt; .01). Photobiomodulation using laser irradiation with wavelengths of 680 and 830 nm had a better degree of bone integration than the control group after 6 weeks of observation time.

Effect of Photobiomodulation on Transforming Growth Factor-β1, Platelet-Derived Growth Factor-BB, and Interleukin-8 Release in Palatal Wounds After Free Gingival Graft Harvesting: A Randomized Clinical Study

Objective: This study evaluated the impact of photobiomodulation (PBM) on the healing of the donor palatal area following free gingival graft (FGG) harvesting by examining changes in transforming growth factor (TGF)-β₁, platelet-derived growth factor (PDGF)-BB, and interleukin (IL)-8 levels in palatal wound fluid (PWF). Material and methods: Thirty patients were selected and randomly assigned to receive PBM (laser group) or PBM sham (sham group) in the palatine area after FGG harvesting. A neodymium-doped yttrium aluminum garnet (Nd:YAG) laser (1064 nm) was applied to the test sites immediately after surgery and every 24 h thereafter for 4 days. PWF was collected on Days 7 and 12, and PWF TGF-β₁, PDGF-BB, and IL-8 levels were analyzed by enzyme-linked immunosorbent assays (ELISA). Results: PWF TGF-β₁, PDGF-BB, and IL-8 levels were significantly lower on Day 12 than on Day 7 for both groups. PWF TGF-β₁, PDGF-BB, and IL-8 levels of the laser group were significantly higher than those of sham group on Day 7 (p < 0.05). PWF TGF-β₁ levels were also significantly higher in laser group than in the sham group on Day 12; however, differences in PDGF-BB and IL-8 levels between groups on Day 12 were statistically nonsignificant. Conclusions: Observed increases in PWF TGF-β₁, PDGF-BB, and IL-8 levels suggest that PBM may accelerate wound healing by stimulating production of selected mediators.

Effect of single-dose low-level helium-neon laser irradiation on orthodontic pain: a split-mouth single-blind placebo-controlled randomized clinical trial

BACKGROUND

Pain is the most common complication of orthodontic treatment. Low-level laser therapy (LLLT) has been suggested as a new analgesic treatment free of the adverse effects of analgesic medications. However, it is not studied thoroughly, and the available studies are quite controversial. Moreover, helium neon (He-Ne) laser has not been assessed before.

METHODS

This split-mouth placebo-controlled randomized clinical trial was performed on 16 male and 14 female orthodontic patients requiring bilateral upper canine retraction. The study was performed at a private clinic in Sari, Iran, in 2014. It was single blind: patients, orthodontist, and personnel were blinded of the allocations, but the laser operator (periodontist) was not blinded. Once canine retractor was activated, a randomly selected maxillary quarter received a single dose of He-Ne laser irradiation (632.8 nm, 10 mw, 6 j/cm(2) density). The other quarter served as the placebo side, treated by the same device but powered off. In the first, second, fourth, and seventh days, blinded patients rated their pain sensed on each side at home using visual analog scale (VAS) questionnaires. There was no harm identified during or after the study. Pain changes were analyzed using two- and one-way repeated-measures ANOVA, Bonferroni, and t-test (α = 0.01, β > 0.99). This trial was not registered. It was self-funded by the authors.

RESULTS

Sixteen males and 11 females remained in the study (aged 12-21). Average pain scores sensed in all 4 intervals on control and laser sides were 4.06 ± 2.85 and 2.35 ± 1.77, respectively (t-test P < 0.0001). One-way ANOVA showed significant pain declines over time, in each group (P < 0.0001). Two-way ANOVA showed significant effects for LLLT (P < 0.0001) and time (P = <0.0001).

CONCLUSIONS

Single-dose He-Ne laser therapy might reduce orthodontic pain caused by retracting maxillary canines.

Effects of low-power light therapy on wound healing: LASER x LED

Several studies demonstrate the benefits of low-power light therapy on wound healing. However, the use of LED as a therapeutic resource remains controversial. There are questions regarding the equality or not of biological effects promoted by LED and LASER. One objective of this review was to determine the biological effects that support the use of LED on wound healing. Another objective was to identify LED´s parameters for the treatment of wounds. The biological effects and parameters of LED will be compared to those of LASER. Literature was obtained from online databases such as Medline, PubMed, Science Direct and Scielo. The search was restricted to studies published in English and Portuguese from 1992 to 2012. Sixty-eight studies in vitro and in animals were analyzed. LED and LASER promote similar biological effects, such as decrease of inflammatory cells, increased fibroblast proliferation, stimulation of angiogenesis, granulation tissue formation and increased synthesis of collagen. The irradiation parameters are also similar between LED and LASER. The biological effects are dependent on irradiation parameters, mainly wavelength and dose. This review elucidates the importance of defining parameters for the use of light devices.

Effect of red and near-infrared wavelengths on low-level laser (light) therapy-induced healing of partial-thickness dermal abrasion in mice

Low-level laser (light) therapy (LLLT) promotes wound healing, reduces pain and inflammation, and prevents tissue death. Studies have explored the effects of various radiant exposures on the effect of LLLT; however, studies of wavelength dependency in in vivo models are less common. In the present study, the healing effects of LLLT mediated by different wavelengths of light in the red and near-infrared (NIR) wavelength regions (635, 730, 810, and 980 nm) delivered at constant fluence (4 J/cm(2)) and fluence rate (10 mW/cm(2)) were evaluated in a mouse model of partial-thickness dermal abrasion. Wavelengths of 635 and 810 nm were found to be effective in promoting the healing of dermal abrasions. However, treatment using 730- and 980-nm wavelengths showed no sign of stimulated healing. Healing was maximally augmented in mice treated with an 810-nm wavelength, as evidenced by significant wound area reduction (p < 0.05), enhanced collagen accumulation, and complete re-epithelialization as compared to other wavelengths and non-illuminated controls. Significant acceleration of re-epithelialization and cellular proliferation revealed by immunofluorescence staining for cytokeratin-14 and proliferating cell nuclear antigen (p < 0.05) was evident in the 810-nm wavelength compared with other groups. Photobiomodulation mediated by red (635 nm) and NIR (810 nm) light suggests that the biological response of the wound tissue depends on the wavelength employed. The effectiveness of 810-nm wavelength agrees with previous publications and, together with the partial effectiveness of 635 nm and the ineffectiveness of 730 and 980 nm wavelengths, can be explained by the absorption spectrum of cytochrome c oxidase, the candidate mitochondrial chromophore in LLLT.

Laser irradiation affects enzymatic antioxidant system of streptozotocin-induced diabetic rats

The aim of the present study was to analyze the effect of low-power laser irradiation in the antioxidant enzymatic system of submandibular (SMG) and parotid (PG) salivary glands of streptozotocin-induced diabetic rats. The animals were randomly divided into six groups: three diabetic groups (D0, D5, and D20) and three non-diabetic groups (C0, C5, and C20), according to laser dose received (0, 5, and 20 J/cm(2), respectively). Areas of approximately 1 cm(2) were demarcated in the salivary glands (each parotid and both submandibular glands) and after irradiated according to Simões et.al. (Lasers Med Sci 24:202-208, 2009). A diode laser (660 nm/100 mW) was used, with laser beam spot of 0.0177 cm(2). The group treated with 5 J/cm(2) laser dose was subjected to irradiation for 1 min and 4 s (total irradiation time) and the group treated with 20 J/cm(2) laser dose was subjected to irradiation for 4 min and 16 s. Twenty-four hours after irradiation the animals were euthanized and the salivary glands were removed for biochemical analysis. The total antioxidant values (TA), the activity of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase enzymes were determined. SOD and CAT activities, as well as TA were higher in SMG of irradiated diabetic rats. However, in SMG of non-diabetic rats, laser irradiation decreased TA values and led to an increase in the CAT activity. In addition, there was a decrease in the activity of CAT in PG of diabetic and non-diabetic animals after laser irradiation. According to the results of the present study, low-power laser irradiation can affect the enzymatic antioxidant system of salivary glands of streptozotocin-induced diabetic rats.