Responses of melanoma cells to photobiomodulation depend on cell pigmentation and light parameters.

Melanoma is a highly aggressive skin cancer that requires new approaches for its management. Low-level laser therapy, currently named photobiomodulation therapy (PBM), has been used to improve different conditions but its effects and safe use on melanoma remain unexplored. Herein, we investigated the PBM impact on melanoma cells differing by pigmentation using near-infrared (NIR) and red lasers in vitro. In vivo, we evaluated the effects of the red laser on melanoma-bearing mice. Amelanotic (SK-MEL-37) and melanotic (B16F10) cells were exposed in vitro to a NIR (780 nm, 40 mW) or a red laser (660 nm, 40 mW) in 3 different light doses: 30, 90, and 150 J/cm2 and responses were assessed regarding mitochondrial activity, invasiveness, migration, and VEGF production. In vivo, melanoma-bearing mice received the red laser delivering 150 J/cm2 directly to the tumor on 3 consecutive days. Mice were monitored for 15 days regarding tumor progression and mouse survival. We noticed that amelanotic cells were unresponsive to NIR light. In contrast, NIR irradiation at 30 J/cm2 promoted an increase in the invasiveness of pigmented cells, even though all light doses have inhibited cell migration. Regarding the red laser on pigmented cells, the highest light dose (150 J/cm2) decreased the VEGF production and migration. In vivo, melanoma-bearing mice treated with red laser showed smaller tumor volume and longer survival than controls. We conclude that PBM appears to be safe for amelanotic non-pigmented melanoma but triggers different responses in melanotic pigmented cells depending on light parameters. Additionally, a high dose of red laser impairs the invasive behavior of melanoma cells, probably due to the decrease in VEGF synthesis, which may have contributed to tumor arrest and increased mouse survival. These findings suggest that red laser therapy could be a new ally in the supportive care of melanoma patients.

Towards effective cutaneous leishmaniasis treatment with light-based technologies. A systematic review and meta-analysis of preclinical studies.

Cutaneous leishmaniasis (CL) is a neglected disease that represents a serious global public health concern. We performed a systematic review with meta-analysis targeting the use of light-based therapies on CL in preclinical studies since they are essential to identify the benefits, challenges, and limitations of proposing new technologies to fight CL. We searched Pubmed and Web of Science to include original preclinical researches in English that used light-based technologies to fight CL. Inclusion criteria encompassed any animal model for CL induction, an untreated infected group as the comparator, reliable and consistent methodology to develop and treat CL, focus on an antimicrobial therapeutic approach, and data for lesion size and/or parasite load in the infection site. We identified eight eligible articles, and all of them used photodynamic therapy (PDT). For the meta-analysis, three studies were included regarding the parasite load in the infection site and four comprised the lesion size. No overall statistically significant differences were observed between untreated control and PDT groups for parasite load. Differently, PDT significantly reduced the lesion size regardless of the protocol used to treat CL (in mm, SMD: -1.90; 95% CI: -3.74 to -0.07, p = 0.04). This finding is particularly encouraging since CL promotes disfiguring lesions that profoundly affect the quality of life of patients. We conclude that PDT is a new promising technology able to be topically used against CL if applied in more than one session, making it a promising ally for the management of CL.

Photobiomodulation therapy combined with radiotherapy in the treatment of triple-negative breast cancer-bearing mice.

This work investigated the effect of photobiomodulation therapy (PBM) combined with radiotherapy (RT) on triple-negative breast cancer (TNBC)-bearing mice. Female BALB/c mice received 4 T1 cells into a mammary fat pad. Local RT was performed with a total dose of 60 Gy divided into 4 consecutive sessions of 15 Gy. For PBM, a red laser was used in three different protocols: i-) single exposure delivering 150 J.cm-2 (24 h after the last RT session), and ii-) radiant exposure of 150 J.cm-2 or iii-) fractionated radiant exposure of 37.5 J.cm-2 (after each RT session). Tumor volume, complete blood cell count, clinical condition, metastasis, and survival of animals were monitored during 3 weeks post-RT. Our results demonstrated that regardless of the protocol, PBM arrested the tumor growth, improved the clinical condition, and prevented hemolytic anemia. Besides, although PBM groups have exhibited a high neutrophil:lymphocyte ratio (NLR), they decreased the number of lung metastases and enhanced mouse survival. Worthy of note, PBM should be used along with the RT sessions in higher radiant exposures, since PBM at 150 J.cm-2 per session significantly extended the survival rate. Together, these data suggest PBM could be a potential ally to RT to fight TNBC.

Global priority multidrug-resistant pathogens do not resist photodynamic therapy.

Microbial drug-resistance demands immediate implementation of novel therapeutic strategies. Antimicrobial photodynamic therapy (aPDT) combines the administration of a photosensitizer (PS) compound with low-irradiance light to induce photochemical reactions that yield reactive oxygen species (ROS). Since ROS react with nearly all biomolecules, aPDT offers a powerful multitarget method to avoid selection of drug-resistant strains. In this study, we assayed photodynamic inactivation under a standardized method, combining methylene blue (MB) as PS and red light, against global priority pathogens. The species tested include Acinetobacter baumannii, Klebsiella aerogenes, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Enterococcus faecium, Enterococcus faecalis, Staphylococcus aureus, Candida albicans and Cryptococcus neoformans. Our strain collection presents resistance to all tested antimicrobials (>50). All drug-resistant strains were compared to their drug-sensitive counterparts. Regardless of resistance phenotype, MB-aPDT presented species-specific dose-response kinetics. More than 5log10 reduction was observed within less than 75 s of illumination for A. baumannii, E. coli, E. faecium, E. faecalis and S. aureus and within less than 7 min for K. aerogenes, K. pneumoniae, P. aeruginosa, C. albicans and C. neoformans. No signs of correlations in between drug-resistance profiles and aPDT sensitivity were observed. Therefore, MB-aPDT can provide effective therapeutic protocols for a very broad spectrum of pathogens. Hence, we believe that this study represents a very important step to bring aPDT closer to implementation into mainstream medical practices.

Effects of corticopuncture (CP) and low-level laser therapy (LLLT) on the rate of tooth movement and root resorption in rats using micro-CT evaluation.

The aim of this study was to compare the rate of tooth displacement, quantity of root resorption, and alveolar bone changes in five groups: corticopuncture (CP), low-level laser therapy (LLLT), CP combined with LLLT (CP + LLLT), control (C), and negative control (NC). A total of 60 half-maxilla from 30 male Wistar rats (10 weeks old) were divided randomly into five groups: three (CP, LLLT, and CP + LLLT) test groups with different stimulation for accelerated-tooth-movement (ATM), one control (C) group, and one negative control (NC) group with no tooth movement. Nickel-titanium coil springs with 50 g of force were tied from the upper left and right first molars to micro-implants placed behind the maxillary incisors. For the CP and CP + LLLT groups, two perforations in the palate and one mesially to the molars were performed. For the LLLT and CP + LLLT groups, GaAlAs diode laser was applied every other day for 14 days (810 nm, 100 mW, 15 s). The tooth displacements were measured directly from the rat's mouth and indirectly from microcomputer (micro-CT) tomographic images. Bone responses at the tension and compression sites and root resorption were analyzed from micro-CT images. The resulting alveolar bone responses were evaluated by measuring bone mineral density (BMD), bone volume fraction (BV/TV), and trabecular thickness (TbTh). Root resorption crater volumes were measured on both compression and tension sides of mesial and distal buccal roots. The tooth displacement in the CP + LLLT group was the greatest when measured clinically, followed by the CP, LLLT, and control groups (C and NC), respectively (p <0.05). The tooth movements measured from micro-CT images showed statistically higher displacement in the CP and CP + LLLT groups compared to the LLLT and control groups. The BMD, BV/TV, and TbTh values were lower at the compression side and higher at the tension side for all three test groups compared to the control group. The root resorption crater volume of the distal buccal root was higher in the control group, followed by CP, LLLT, and CP + LLLT, mostly at the compression site. Combining corticopuncture and low-level laser therapy (CP + LLLT) produced more tooth displacement and less root resorption at the compression side. The combined technique also promoted higher alveolar bone formation at the tension side.

Low-level laser therapy stimulates bone metabolism and inhibits root resorption during tooth movement in a rodent model.

This study evaluated the biological effects of low-level laser therapy (LLLT) on bone remodeling, tooth displacement and root resorption, occurred during the orthodontic tooth movement. Upper first molars of a total of sixty-eight male rats were subjected to orthodontic tooth movement and euthanized on days 3, 6, 9, 14 and 21 days and divided as negative control, control and LLLT group. Tooth displacement and histomorphometric analysis were performed in all animals; scanning electron microscopy analysis was done on days 3, 6 and 9, as well as the immunohistochemistry analysis of RANKL/OPG and TRAP markers. Volumetric changes in alveolar bone were analyzed using MicroCT images on days 14 and 21. LLLT influenced bone resorption by increasing the number of TRAP-positive osteoclasts and the RANKL expression at the compression side. This resulted in less alveolar bone and hyalinization areas on days 6, 9 and 14. LLLT also induced less bone volume and density, facilitating significant acceleration of tooth movement and potential reduction in root resorption besides stimulating bone formation at the tension side by enhancing OPG expression, increasing trabecular thickness and bone volume on day 21. Taken together, our results indicate that LLLT can stimulate bone remodeling reducing root resorption in a rat model. LLLT improves tooth movement via bone formation and bone resorption in a rat model.

Photobiomodulation reduces abdominal adipose tissue inflammatory infiltrate of diet-induced obese and hyperglycemic mice.

Systemic inflammation is closely related to the development of insulin resistance and type-2 diabetes, since the activation of pro-inflammatory pathways leads to inhibition of insulin signaling. Although photobiomodulation (PBM) has proven beneficial effects on the treatment of inflammatory disorders, the phototherapeutic approach to manage the chronic inflammatory component of obesity and hyperglycemia had never been explored. In this work, obese and hyperglycemic mice are treated with PBM, and their body mass, glycemia and inflammatory infiltrate of abdominal adipose tissue are evaluated. During four weeks, irradiated animals are exposed to six irradiation sessions using an 843 nm LED (5.7 J cm-2 at 19 mW cm-2 per session). Non-irradiated control animals display inflammatory areas almost five times greater than the treated group (p < 0.001). This result on inflammatory infiltrate may have caused impacts on the significant lower blood glucose level from irradiated animals (p = 0.04), twenty-four hours after the last irradiation session. PBM on obese and hyperglycemic mice reduced five times the areas of inflammatory infiltrate within abdominal adipose tissue (a, b), whereas dense inflammatory regions were a common finding amidst non-irradiated animals (c). The asterisks on (c) correspond to the inflammatory infiltrate permeating adipocytes.

Exploring the effects of low-level laser therapy on fibroblasts and tumor cells following gamma radiation exposure.

Ionizing radiation (IR) induces DNA damage and low-level laser therapy (LLLT) has been investigated to prevent or repair detrimental outcomes resulting from IR exposure. Few in vitro studies, however, explore the biological mechanisms underlying those LLLT benefits. Thus, in this work, fibroblasts and tumor cells are submitted to IR with doses of 2.5 Gy and 10 Gy. After twenty-four-h, the cells are exposed to LLLT with fluences of 30 J cm-2 , 90 J cm-2 , and 150 J cm-2 . Cellular viability, cell cycle phases, cell proliferation index and senescence are evaluated on days 1 and 4 after LLLT irradiation. For fibroblasts, LLLT promotes - in a fluence-dependent manner - increments in cell viability and proliferation, while a reduction in the senescence was observed. Regarding tumor cells, no influences of LLLT on cell viability are noticed. Whereas LLLT enhances cell populations in S and G2 /M cell cycle phases for both cellular lines, a decrease in proliferation and increase in senescence was verified only for tumor cells. Putting together, the results suggest that fibroblasts and tumor cells present different responses to LLLT following exposure to gamma-radiation, and these promising results should stimulate further investigations. Senescence of tumor cells and fibroblasts on the 4th day after ionizing radiation (IR) and low-level laser therapy (LLLT) exposures. The number of senescent cells increased significantly for tumor cells (a) while for fibroblasts no increment was observed (b). The blue collor indicates senescence activity.

Light therapy modulates serotonin levels and blood flow in women with headache. A preliminary study.

In this study, we looked at the possible effects of low-level laser therapy (LLLT) on blood flow velocity, and serotonin (5-HT) and cholinesterase levels in patients with chronic headache associated with temporomandibular disorders (TMD). LLLT has been clinically applied over the past years with positive results in analgesia and without the report of any side effects. The understanding of biological mechanisms of action may improve clinical results and facilitate its indication. Ten patients presenting headache associated with TMD completed the study. An 830-nm infrared diode laser with power of 100 mW, exposure time of 34 s, and energy of 3.4 J was applied on the tender points of masseter and temporal muscle. Blood flow velocity was determined via ultrasound Doppler velocimetry before and after laser irradiation. The whole blood 5-HT and cholinesterase levels were evaluated three days before, immediately, and three days after laser irradiation. Pain score after treatment decreased to a score of 5.8 corresponding to 64% of pain reduction (P < 0.05). LLLT promoted a decrease in the blood flow velocity (P < 0.05). In addition, the 5-HT levels were significantly increased three days after LLLT (P < 0.05). The cholinesterase levels remained unchanged at the analyzed time points (P > 0.05). Our findings indicated that LLLT regulates blood flow in the temporal artery after irradiation and might control 5-HT levels in patients suffering with tension-type headache associated to TMD contributing to pain relief.

Photodynamic therapy for pododermatitis in penguins.

Pododermatitis is currently one of most frequent and important clinical complications in seabirds kept in captivity or in rehabilitation centers. In this study, five Magellanic penguins with previous pododermatitis lesions on their footpad were treated with photodynamic therapy (PDT). All PDT treated lesions successfully regressed and no recurrence was observed during the 6-month follow-up period. PDT seems to be an inexpensive and effective alternative treatment for pododermatitis in Magellanic penguins encouraging further research on this topic.

The influence of red laser irradiation timeline on burn healing in rats.

Low-level laser therapy (LLLT) promotes biomodulation of wound healing and literature reports that light delivery during the inflammation could play a different role compared with latter phases of the healing process. The objective of this study was to investigate whether single dose of a red laser (λ = 660 nm) is different from fractionated delivery protocol in full thickness burns. Two lesions were inflicted on the back of 36 rats. In the fractionated dose group (FG), the lesions were irradiated with 1 J/cm² on days 1, 3, 8, and 10 post-wounding. In the single dose group (SG), the lesions were irradiated with 4 J/cm² on day 1, immediately after injury. Control lesions (CG) received no light and were left to heal spontaneously. Blood flow was measured on days 1, 3, 8, 10, 15, and 21 using laser Doppler flowmetry. Animals were killed on days 3, 8, 10, 15, and 21. Skin specimens were obtained and routinely processed for hematoxylin and eosin. The specimens were evaluated according to differential leukocyte counting and angiogenesis. Statistical analysis was performed, and significance was accepted at p < 0.05. Irradiated groups showed a peak of new vessels on day 15 while, for CG, the peak was on day 21. On day 21, FG exhibited a significantly greater number of cumulative neutrophils while SG showed a higher number of mononuclear cells. Our results confirm that both protocols used accelerate angiogenesis and stimulate leukocyte chemotaxis on burn treatment. In addition, this work suggests that a single-dose LLLT accelerates the inflammatory phase of skin repair.

Prevention and treatment of mice paw edema by near-infrared low-level laser therapy on lymph nodes.

Low-level laser therapy (LLLT) has been demonstrated to modulate inflammatory processes and immunological responses. The aim of this work was to investigate the hypothesis that near infrared LLLT (830 nm) over lymph nodes may reduce paw edema and contribute to the modulation of inflammation. The edema was induced by carrageenan inoculation (CGN) into the plantar surface of 100 male mice left hind paw. Animals were divided into five groups: CGN (control), no treatment; Diclo, sodium diclofenac; Paw, LLLT on the paw; Ly, LLLT on the inguinal lymph nodes; and Paw+Ly, LLLT in both paw and lymph nodes, and subdivided according to moment of irradiation: A-1 h and 2 h before CGN, B-1 h and immediately before CGN, C-1 and 2 h after CGN, and D-3.5 and 4.5 h after CGN. The parameters used were: energy=1 J, fluence=35 J/cm(2), power=100 mW during 10 s. Paw volume was measured before and 1 to 6 h after CGN, and myeloperoxidase (MPO) activity was analyzed. Edema prevention was obtained by the irradiation of Paw+Ly at moment A and at Ly at moment B, inhibition of edema formation was achieved by either Paw or Ly at moment C, and edema treatment was obtained by Paw or Ly at moment D (p<0.05). MPO activity was significantly reduced on Paw at moment A, Paw and Ly on C, and in all irradiated groups on B and D. Our results suggest that LLLT was able to produce both anti-inflammatory and pro-inflammatory effects depending on to the site and moment of irradiation.

Antimicrobial photodynamic therapy in the treatment of oral candidiasis in HIV-infected patients.

OBJECTIVE: Antimicrobial photodynamic therapy (aPDT) has been used to combat local infections, and it consists of the combination of a photosensitizer, a light source, and reactive oxygen species (ROS) to kill microbial cells. In this study, we evaluated the effectiveness of aPDT in the treatment of candidiasis in HIV-infected patients. METHODS: Twenty-one patients were divided into three groups. Control group (CG) was treated with the conventional medication for candidiasis (fluconazole 100 mg/day during 14 days). Laser group (LG) was subjected to low-level laser therapy (LLLT), wavelength 660 nm, power of 30 mW, and fluence of 7.5 J/cm(2), in contact with mucosa during 10 sec on the affected point. An aPDT group (aPDTG) was treated with aPDT, that is, combination of a low-power laser and methylene blue 450 µg/mL. Pre-irradiation time was 1 min. Parameters of irradiation were the same ones as for the LG, and patients were single irradiated. Patients were clinically evaluated and culture analysis was performed before, immediately after, and 7, 15, and 30 days after the treatment. RESULTS: Our results showed that fluconazole was effective; however, it did not prevent the return of the candidiasis in short-term. LLLT per se did not show any reduction on Candida spp. aPDT eradicated 100% of the colonies of this fungus and the patients did not show recurrence of candidiasis up to 30 days after the irradiation. CONCLUSIONS: These findings suggest that aPDT is a potential approach to oral candidiasis treatment in HIV-infected patients.

Effect of photodynamic therapy on clinical isolates of Staphylococcus spp

Staphylococcus spp. are opportunistic microorganisms known for their capacity to develop resistance against antimicrobial agents. The objective of this study was to evaluate the effect of photodynamic therapy (PDT) on 20 Staphylococcus strains isolated from the human oral cavity, including S. aureus, S. schleiferi, S. epidermidis, S. capitis, S. haemolyticus, and S. lentus. A suspension of each Staphylococcus strain (10(6) cells/mL) was submitted to PDT using methylene blue and a low power laser. The isolated effects of methylene blue, laser treatment and ciprofloxacin were also evaluated. After the experimental treatments, 0.1 mL aliquots of the suspensions were seeded onto BHI agar for determination of the number of colony-forming units (CFU/mL). The results were analyzed by analysis of variance and Tukey's test (p < 0.05). The mean reduction in bacterial counts of the strains submitted to PDT ranged from 4.89 to 6.83 CFU (log10)/mL, with the observation of a decreasing susceptibility to treatment of S. schleiferi, S. haemolyticus, S. epidermidis, S. capitis, S. aureus, and S. lentus. The results showed that PDT was effective in reducing the number of viable cells of all clinical Staphylococcus isolates studied.

Effect of photodynamic therapy on clinical isolates of Staphylococcus spp.

Staphylococcus spp. are opportunistic microorganisms known for their capacity to develop resistance against antimicrobial agents. The objective of this study was to evaluate the effect of photodynamic therapy (PDT) on 20 Staphylococcus strains isolated from the human oral cavity, including S. aureus, S. schleiferi, S. epidermidis, S. capitis, S. haemolyticus, and S. lentus. A suspension of each Staphylococcus strain (10(6) cells/mL) was submitted to PDT using methylene blue and a low power laser. The isolated effects of methylene blue, laser treatment and ciprofloxacin were also evaluated. After the experimental treatments, 0.1 mL aliquots of the suspensions were seeded onto BHI agar for determination of the number of colony-forming units (CFU/mL). The results were analyzed by analysis of variance and Tukey's test (p < 0.05). The mean reduction in bacterial counts of the strains submitted to PDT ranged from 4.89 to 6.83 CFU (log10)/mL, with the observation of a decreasing susceptibility to treatment of S. schleiferi, S. haemolyticus, S. epidermidis, S. capitis, S. aureus, and S. lentus. The results showed that PDT was effective in reducing the number of viable cells of all clinical Staphylococcus isolates studied.

Low-level laser therapy in burning mouth syndrome patients: a pilot study.

OBJECTIVE: The aim of this study was to investigate the effect of low-level laser therapy (LLLT) on the treatment of burning mouth syndrome (BMS). In addition, the laser effect was compared on the different affected oral sites. MATERIALS AND METHODS: Eleven subjects with a total of 25 sites (tongue, lower lip, upper lip, and palate) affected by a burning sensation were selected. The affected areas were irradiated once a week for three consecutive weeks with an infrared laser (λ = 790 nm). The probe was kept in contact with the tissue, and the mucosal surface was scanned during the irradiation. The exposure time was calculated based on the fluence of 6 J/cm(2), the output power of 120 mW, and the area to be treated. Burning intensity was recorded through a visual analog scale before and after the treatment and at the 6-week follow-up. The percentage of the improvement in symptoms was also obtained. RESULTS: Burning intensity at the end of the laser therapy was statistically lower than at the beginning (p < 0.01). Patients reported an 80.4% reduction in the intensity of symptoms after laser treatment. There was no statistical difference between the end of the treatment and the 6-week follow-up, except for the tongue site. CONCLUSION: Under the investigated parameters, infrared LLLT proved to be a valuable alternative for BMS treatment, providing a significant and lasting reduction in symptoms.

Estudo do grau de polarização linear em lesões de pele irradiadas com laser durante o processo de cicatrização / Study of linear polarization degree in skin lesions irradiated with laser during the healing process

Introdução: Alguns dos fatores determinantes na resposta fotobiológica da terapia laser em baixa intensidade são o estado fisiológico do tecido e as características ópticas do feixe, como a polarização de seu campo elétrico. Objetivos: Investigaram-se o grau e a preservação da polarização linear em amostras de pele de rato sadia e lesionada. Métodos: Criolesões foram realizadas no dorso de ratos e tratadas por quatro dias com 1J/cm2. O campo elétrico do laser foi alinhado a 0º e a 90º em relação à coluna vertebral dos animais. Resultados: A polarização foi mantida nas camadas superficiais da pele, sendo mais preservada na pele queimada. Durante o processo cicatricial, a lesão cujo campo elétrico foi alinhado a 0º em relação à coluna vertebral mostrou um grau de polarização semelhante àquele da pele sadia. Conclusões: O processo de reparação da pele foi influenciado pela polarização linear do feixe laser de He-Ne.

Introduction: The physiological conditions of tissue and optical characteristics of beam, like electric polarization, are some of the determining factors in the photobiological response of low intensity laser therapy. Objectives: The degree and preservation of linear polarization in samples of healthy and injured rat skin were investigated. Methods: Cryolesions were created in the lower back of rats and treated for four days with 1J/cm2. The laser electric was aligned in 0º and 90º to the backbone of the animals. Results: The polarization was maintained in the superficial layers of the skin, being better preserved in burned skin. During the wound healing, the lesion whose electric was aligned parallel to the spine showed a degree of bias similar to that of healthy skin. Conclusions: The repair process of skin was influenced by linear polarization of He-Ne laser beam.

Photodynamic therapy can be effective as a treatment for herpes simplex labialis.

BACKGROUND DATA AND OBJECTIVE: Herpes is a common infectious disease that is caused by human herpesviruses. Several treatments have been proposed, but none of them prevent reactivation of the virus. This article describes the use of photodynamic therapy (PDT) as a treatment for herpes lesions, and reports on four cases. MATERIALS AND METHODS: PDT was used as an adjuvant therapy for the treatment of herpes labialis in four patients. A special type of 0.01% (m/V) of methylene blue solution was applied to the vesicular stage of herpesviral disease and the lesions were irradiated with laser energy (wavelength 660 nm, energy density 120 J/cm(2), output power of 40 mW, 2 min per point, 4.8 J of energy/point, at four points). After 24 h the patients returned and phototherapy was repeated with the same equipment, this time with 3.8 J/cm(2) and 15 mW, for a total dose of 0.6 J. The same procedure was repeated 72 h and 1 wk later. RESULTS: Treatment with low-level laser therapy can be considered as an option in the treatment of herpes labialis, and decreases the frequency of vesicle recurrence and provides comfort for patients. No significant acute side effects were noted and the lesions healed rapidly. CONCLUSION: Treatment of herpes labialis with PDT was effective, had no side effects, and when associated with laser phototherapy, accelerated the healing process.

Effects of low-power red laser on dentine-pulp interface after cavity preparation. An ultrastructural study.

OBJECTIVE: Studies on the influence of low-power red laser on the repair of dental structures are very scarce. This study investigated the effects of the laser therapy on the ultrastructure of the dentine-pulp interface after conservative class I cavity preparation. DESIGN: Two female volunteers with 8 premolars indicated for extraction for orthodontic reasons were recruited. Class I cavities were prepared and the teeth were randomly divided into two groups. The first group received treatment with a GaA1As laser, lambda=660nm, power of 30mW and energy dose of 2J/cm(2), directly and perpendicularly into the cavity in a single visit. After the irradiation, the cavities were filled with composite resin. The second group received the same treatment, except by the laser therapy. RESULTS: Twenty-eight days post-preparation, the teeth were extracted and processed for transmission electron microscopy analysis. Two sound teeth, without cavity preparation, were also studied. The irradiated group presented odontoblast process in higher contact with the extracellular matrix and the collagen fibrils appeared more aggregated and organised than those of control group. These results were also observed in the healthy teeth. CONCLUSION: These findings suggest that laser irradiation accelerates the recovery of the dental structures involved in the cavity preparation at the predentine region.

Transmissão do laser de baixa potência através de filmes plásticos de PVC / Transmission of low-power laser through PVC plastic film

O laser de baixa potência é utilizado na fisioterapia na cicatrização de lesões, para acelerar a reparação tecidual. Um filme de PVC na ponteira do equipamento é comumente usado na prática clínica para evitar a contaminação da lesão pelo equipamento, principalmente em mucosas e áreas cruentas...

Low-intensity laser application is used in physical therapy in view of accelerating wound repair processes. In clinical practice, a PVC film is commonly used covering the lasers pen's tip to avoid contamination of the wound by the equipment, mainly on mucosa and cruent...