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1.
PLoS One ; 14(1): e0210211, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-30625210

RESUMEN

The effects of low-level laser therapy (LLLT) and natural latex protein (F1, Hevea brasiliensis) were evaluated on crush-type injuries (15kg) to the sciatic nerve in the expressions of nerve growth factor (NGF) and vascular endothelium growth factor (VEGF) and ultrastructural morphology to associate with previous morphometric data using the same protocol of injury and treatment. Thirty-six male rats were allocated into six experimental groups (n = 6): 1-Control; 2-Exposed nerve; 3-Injured nerve; 4-LLLT (15J/cm2, 780nm, 30mW, Continuous Wave) treated injured nerve; 5-F1 (0,1mg) treated injured nerve; and 6-LLLT&F1 treated injured nerve. Four or eight weeks after, sciatic nerve samples were processed for analysis. NGF expression were higher (p<0.05) four weeks after in all injured groups in comparison to Control (Med:0.8; Q1:0; Q3:55.5%area). Among them, the Injured (Med:70.7; Q1:64.4; Q3:77.5%area) showed the highest expression, and F1 (Med:17.3; Q1:14.1; Q3:21.7%area) had the lowest. At week 8, NGF expressions decreased in the injured groups. VEGF was expressed in all groups; its higher expression was observed in the injured groups 4 weeks after (Injured. Med:29.5; F1. Med:17.7 and LLLT&F1. Med:19.4%area). At week 8, a general reduction of VEGF expression was noted, remaining higher in F1 (Med:35.1; Q1.30.6; Q3.39.6%area) and LLLT&F1 (Med:18.5; Q1:16; Q3:25%area). Ultrastructural morphology revealed improvements in the treated groups; 4 weeks after, the F1 group presented greater quantity and diameter of the nerve fibers uniformly distributed. Eight weeks after, the F1 and LLLT&F1 showed similar characteristics to the non-injured groups. In summary, these results and our previous studies indicated that F1 and LLLT may favorably influence the healing of nerve crush injury. Four weeks after nerve injury F1 group showed the best results suggesting recovery acceleration; at 8th week F1 and LLLT&F1 groups presented better features and higher vascularization that could be associated with VEGF maintenance.


Asunto(s)
Hevea/química , Terapia por Luz de Baja Intensidad , Traumatismos de los Nervios Periféricos/terapia , Proteínas de Plantas/administración & dosificación , Nervio Ciático/lesiones , Animales , Lesiones por Aplastamiento/complicaciones , Modelos Animales de Enfermedad , Humanos , Péptidos y Proteínas de Señalización Intercelular/metabolismo , Látex/química , Masculino , Microscopía Electrónica de Transmisión , Regeneración Nerviosa/efectos de los fármacos , Regeneración Nerviosa/efectos de la radiación , Traumatismos de los Nervios Periféricos/etiología , Proteínas de Plantas/aislamiento & purificación , Ratas , Ratas Wistar , Recuperación de la Función , Nervio Ciático/fisiología , Nervio Ciático/ultraestructura , Cicatrización de Heridas/efectos de los fármacos , Cicatrización de Heridas/efectos de la radiación
2.
J Biophotonics ; 11(9): e201800110, 2018 09.
Artículo en Inglés | MEDLINE | ID: mdl-29749025

RESUMEN

Diabetic peripheral neuropathy (DPN) is a nervous disorder caused by diabetes mellitus, affecting about 50% of patients in clinical medicine. Chronic pain is one of the major and most unpleasant symptoms developed by those patients, and conventional available treatments for the neuropathy, including the associated pain, are still unsatisfactory and benefit only a small number of patients. Photobiomodulation (PBM) has been gaining clinical acceptance once it is able to promote early nerve regeneration resulting in significant improvement in peripheral nerves disabilities. In this work, the effects of PBM (660 nm, 30 mW, 1.6 J/cm2 , 0.28 cm2 , 15 s in a continuous frequency) on treating DPN-induced pain and nerve damage were evaluated in an experimental model of diabetic-neuropathy induced by streptozotocin in mice. PBM-induced antinociception in neuropathic-pain mice was dependent on central opioids release. After 21 consecutive applications, PBM increased nerve growth factor levels and induced structural recovery increasing mitochondrial content and regulating Parkin in the sciatic nerve of DPN-mice. Taking together, these data provide new insights into the mechanisms involved in the effects of PBM-therapy emphasizing its therapeutic potential in the treatment of DPN.


Asunto(s)
Diabetes Mellitus Experimental/fisiopatología , Homeostasis/efectos de la radiación , Terapia por Luz de Baja Intensidad , Mitocondrias/efectos de la radiación , Nocicepción/efectos de la radiación , Nervio Ciático/fisiopatología , Nervio Ciático/efectos de la radiación , Animales , Fenómenos Biomecánicos/efectos de la radiación , Diabetes Mellitus Experimental/patología , Diabetes Mellitus Experimental/terapia , Masculino , Ratones , Ratones Endogámicos C57BL , Mitocondrias/metabolismo
3.
Lasers Med Sci ; 32(4): 833-840, 2017 May.
Artículo en Inglés | MEDLINE | ID: mdl-28314941

RESUMEN

Inferior alveolar nerve (IAN) injuries may occur during various dental routine procedures, especially in the removal of impacted lower third molars, and nerve recovery in these cases is a great challenge in dentistry. Here, the IAN crush injury model was used to assess the efficacy of photobiomodulation (PBM) in the recovery of the IAN in rats following crushing injury (a partial lesion). Rats were divided into four experimental groups: without any procedure, IAN crush injury, and IAN crush injury with PBM and sham group with PBM. Treatment was started 2 days after surgery, above the site of injury, and was performed every other day, totaling 10 sessions. Rats were irradiated with GaAs Laser (Gallium Arsenide, Laserpulse, Ibramed Brazil) emitting a wavelength of 904 nm, an output power of 70 mWpk, beam spot size at target ∼0.1 cm2, a frequency of 9500 Hz, a pulse time 60 ns, and an energy density of 6 J/cm2. Nerve recovery was investigated by measuring the morphometric data of the IAN using TEM and by the expression of laminin, neurofilaments (NFs), and myelin protein zero (MPZ) using Western blot analysis. We found that IAN-injured rats which received PBM had a significant improvement of IAN morphometry when compared to IAN-injured rats without PBM. In parallel, all MPZ, laminin, and NFs exhibited a decrease after PBM. The results of this study indicate that the correlation between the peripheral nerve ultrastructure and the associated protein expression shows the beneficial effects of PBM.


Asunto(s)
Terapia por Luz de Baja Intensidad , Nervio Mandibular/metabolismo , Nervio Mandibular/patología , Compresión Nerviosa , Neuropéptidos/metabolismo , Animales , Densitometría , Filamentos Intermedios/metabolismo , Laminina/metabolismo , Masculino , Nervio Mandibular/ultraestructura , Proteína P0 de la Mielina/metabolismo , Ratas Wistar
4.
Muscle Nerve ; 52(5): 869-75, 2015 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-25677810

RESUMEN

INTRODUCTION: In this study we evaluated the characteristics of the tibialis anterior muscle after sciatic nerve crush and treatment with low-level laser therapy (LLLT) or the protein from natural latex (P1). METHODS: We studied the following 6 groups of male Wistar rats: control (CG); exposed nerve (EG); injured nerve (IG); injured nerve with LLLT (LG); injured nerve with P1 (PG); and injured nerve with P1 and LLLT (LPG). RESULTS: After 4 weeks, muscle morphology showed improvement in the treated groups; after 8 weeks, the treated groups resembled controls, especially the PG. Morphometry revealed muscle fiber atrophy after nerve injury, with time-dependent recovery. Histochemical analysis revealed increased intermediate fiber area. The PG was more similar to controls with NADH staining, whereas the LPG more closely resembled controls with SDH staining. CONCLUSION: Treatment using only P1 proved most efficient, revealing a negative interaction between P1 and LLLT.


Asunto(s)
Hevea , Terapia por Láser/métodos , Látex/uso terapéutico , Compresión Nerviosa , Neuropatía Ciática/terapia , Animales , Látex/aislamiento & purificación , Terapia por Luz de Baja Intensidad/métodos , Masculino , Ratas , Ratas Wistar , Neuropatía Ciática/patología , Resultado del Tratamiento
5.
J Neurol Sci ; 349(1-2): 129-37, 2015 Feb 15.
Artículo en Inglés | MEDLINE | ID: mdl-25619570

RESUMEN

This study evaluated the effect of low-level laser therapy (LLLT; 15 J/cm(2)) and a latex protein (F1) on a crush injury of the sciatic (ischiadicus) nerve. Seventy-two rats (male, 250 g) were divided into 6 groups: CG, control; EG, exposed nerve; IG, injured nerve without treatment; LG, injured nerve with LLLT; HG, injured nerve with F1; and LHG, injured nerve with LLLT and F1. After 4 or 8 weeks, the animals were euthanized and samples of the sciatic nerve were collected for morphometric and high-resolution scanning electron microscopy (HRSEM) analysis. After 4 weeks, the morphometry revealed improvements in the treated animals, and the HG appeared to be the most similar to the CG; after 8 weeks, the injured groups showed improvements compared to the previous period, and the results of the treatment groups were more similar to one another. At HRSEM after 4 weeks, the treated groups were similar and showed improvement compared to the IG; after 8 weeks, the LHG and HG had the best results. In conclusion, the treatments resulted in improvement after the nerve injury, and this recovery was time-dependent. In addition, the use of the F1 resulted in the best morphometric and ultrastructural findings.


Asunto(s)
Hevea/química , Látex/administración & dosificación , Terapia por Luz de Baja Intensidad/métodos , Microscopía Electrónica de Rastreo , Fitoterapia , Nervio Ciático/lesiones , Neuropatía Ciática/tratamiento farmacológico , Animales , Látex/química , Masculino , Compresión Nerviosa/efectos adversos , Preparaciones de Plantas , Proteínas de Plantas/administración & dosificación , Proteínas de Plantas/química , Ratas , Ratas Wistar , Recuperación de la Función , Nervio Ciático/efectos de los fármacos , Nervio Ciático/efectos de la radiación , Nervio Ciático/ultraestructura , Neuropatía Ciática/patología , Neuropatía Ciática/radioterapia , Factores de Tiempo
6.
Growth Factors ; 33(1): 8-13, 2015 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-25489629

RESUMEN

Neurotrophins are crucial in relation to axonal regrowth and remyelination following injury; and neural mobilization (NM) is a noninvasive therapy that clinically is effective in neuropathic pain treatment, but its mechanisms remains unclear. We examined the effects of NM on the regeneration of sciatic nerve after chronic constriction injury (CCI) in rats. The CCI was performed on adult male rats, submitted to 10 sessions of NM, starting 14 days after CCI. Then, the nerves were analyzed using transmission electron microscopy and western blot for neural growth factor (NGF) and myelin protein zero (MPZ). We observed an increase of NGF and MPZ after CCI and NM. Electron microscopy revealed that CCI-NM samples had high numbers of axons possessing myelin sheaths of normal thickness and less inter-axonal fibrosis than the CCI. These data suggest that NM is effective in facilitating nerve regeneration and NGF and MPZ are involved in this effect.


Asunto(s)
Manipulaciones Musculoesqueléticas , Proteína P0 de la Mielina/metabolismo , Factor de Crecimiento Nervioso/metabolismo , Regeneración Nerviosa , Traumatismos de los Nervios Periféricos/metabolismo , Animales , Axones/metabolismo , Axones/ultraestructura , Masculino , Proteína P0 de la Mielina/genética , Factor de Crecimiento Nervioso/genética , Traumatismos de los Nervios Periféricos/terapia , Ratas , Ratas Wistar , Nervio Ciático/lesiones , Nervio Ciático/metabolismo , Nervio Ciático/fisiología
7.
Growth Factors ; 32(5): 164-70, 2014 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-25257251

RESUMEN

Hyaluronic acid hydrogels (HAHs) have been used as a carrier of substances and factors in the repair of nervous tissue. Natural latex protein (Hevea brasiliensis, F1) has shown positive effects in treating various types of tissues, including peripheral nerves. This study evaluated the F1 associated with a HAH in a controlled crush injury (axonotmesis) of the sciatic nerve in Wistar rats. The samples were photomicrographed for morphometric and quantitative analyzes using ImageJ 1.47k software (NIH, Bethesda, MD). Morphological, quantitative (myelin area/nerve area ratio and capillary density) and morphometric (minimum nerve fiber diameter, G-Ratio) data revealed an improvement in the recovery of the sciatic nerve with the application of HAH and the combination of HAH and F1 after 4 and 8 weeks of nerve injury. The most efficacious results were observed with the combination of both substances, F1 and HAH, revealing the regenerative capacity of this new biomaterial, which was hardly tested on nerve tissue.


Asunto(s)
Materiales Biocompatibles/química , Ácido Hialurónico/química , Hidrogeles/química , Látex/química , Nervio Ciático/lesiones , Nervio Ciático/patología , Ingeniería de Tejidos/métodos , Animales , Hevea/química , Vaina de Mielina/química , Compresión Nerviosa , Regeneración Nerviosa , Nervios Periféricos/patología , Extractos Vegetales/química , Ratas , Ratas Wistar , Neuropatía Ciática , Temperatura , Cicatrización de Heridas
8.
J Chem Neuroanat ; 57-58: 42-53, 2014 May.
Artículo en Inglés | MEDLINE | ID: mdl-24727411

RESUMEN

The suprachiasmatic nucleus (SCN), which is considered to be the master circadian clock in mammals, establishes biological rhythms of approximately 24 h that several organs exhibit. One aspect relevant to the study of the neurofunctional features of biological rhythmicity is the identification of communication pathways between the SCN and other brain areas. As a result, SCN efferent projections have been investigated in several species, including rodents and a few primates. The fibers originating from the two main intrinsic fiber subpopulations, one producing vasoactive intestinal peptide (VIP) and the other producing arginine vasopressin (AVP), exhibit morphological traits that distinguish them from fibers that originate from other brain areas. This distinction provides a parameter to study SCN efferent projections. In this study, we mapped VIP (VIP-ir) and AVP (AVP-ir) immunoreactive (ir) fibers and endings in the hypothalamus of the primate Sapajus apella via immunohistochemical and morphologic study. Regarding the fiber distribution pattern, AVP-ir and VIP-ir fibers were identified in regions of the tuberal hypothalamic area, retrochiasmatic area, lateral hypothalamic area, and anterior hypothalamic area. VIP-ir and AVP-ir fibers coexisted in several hypothalamic areas; however, AVP-ir fibers were predominant over VIP-ir fibers in the posterior hypothalamus and medial periventricular area. This distribution pattern and the receiving hypothalamic areas of the VIP-ir and AVP-ir fibers, which shared similar morphological features with those found in SCN, were similar to the patterns observed in diurnal and nocturnal animals. This finding supports the conservative nature of this feature among different species. Morphometric analysis of SCN intrinsic neurons indicated homogeneity in the size of VIP-ir neurons in the SCN ventral portion and heterogeneity in the size of two subpopulations of AVP-ir neurons in the SCN dorsal portion. The distribution of fibers and morphometric features of these neuronal populations are described and compared with those of other species in the present study.


Asunto(s)
Arginina Vasopresina/metabolismo , Vías Eferentes/anatomía & histología , Hipotálamo/anatomía & histología , Núcleo Supraquiasmático/anatomía & histología , Péptido Intestinal Vasoactivo/metabolismo , Animales , Cebus , Vías Eferentes/metabolismo , Vías Eferentes/ultraestructura , Hipotálamo/metabolismo , Hipotálamo/ultraestructura , Inmunohistoquímica , Masculino , Fibras Nerviosas/metabolismo , Fibras Nerviosas/fisiología , Fibras Nerviosas/ultraestructura , Área Preóptica/fisiología , Área Preóptica/ultraestructura , Núcleo Supraquiasmático/metabolismo , Núcleo Supraquiasmático/ultraestructura
9.
Biomed Res Int ; 2014: 506051, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-24616895

RESUMEN

Low level laser therapy (LLLT) has been used to relieve pain, inflammation, and wound healing processes. Thus, the skin is overexposed to laser and this effect is not completely understood. This study analyzed the effects of the number of laser applications (three, six, and 10) on the intact skin of the masseteric region in mice of strain HRS/J. The animals (n = 30) were equally divided into control (0 J/cm(2)) and irradiated (20 J/cm(2)), and each of these groups was further equally divided according to the number of laser applications (three, six, and 10) and underwent LLLT on alternate days. Samples were analyzed by light microscopy and transmission electron microscope (TEM). The animals receiving applications exhibited open channels more dilated between the keratinocytes and photobiomodulation effect on endothelial cells and fibroblasts by TEM. Under the light microscope after 10 laser applications, the type I collagen decreased (P < 0.05) compared to the three and six applications. Under these experimental conditions, all numbers of applications provided photobiomodulatory effect on the epidermis and dermis, without damage. More studies are needed to standardize the energy density and number of applications recommended for laser therapy to have a better cost-benefit ratio associated with treatment.


Asunto(s)
Terapia por Luz de Baja Intensidad , Piel/citología , Piel/ultraestructura , Animales , Colágeno Tipo I/metabolismo , Ratones , Piel/efectos de la radiación , Coloración y Etiquetado
10.
Biomed Res Int ; 2013: 597863, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-23936823

RESUMEN

This study analyzed the effects of a low-level laser therapy (LLLT, 15 J/cm(2), 780 nm wavelength) and the natural latex protein (P1, 0.1%) in sciatic nerve after crush injury (15 Kgf, axonotmesis) in rats. Sixty rats (male, 250 g) were allocated into the 6 groups (n = 10): CG-control group; EG-nerve exposed; IG-injured nerve without treatment; LG-crushed nerve treated with LLLT; PG-injured nerve treated with P1; and LPG-injured nerve treated with LLLT and P1. After 4 or 8 weeks, the nerve samples were processed for morphological, histological quantification and ultrastructural analysis. After 4 weeks, the myelin density and morphological characteristics improved in groups LG, PG, and LPG compared to IG. After 8 weeks, PG, and LPG were similar to CG and the capillary density was higher in the LG, PG, and LPG. In the ultrastructural analysis the PG and LPG had characteristics that were similar to the CG. The application of LLLT and/or P1 improved the recovery from the nerve crush injury, and in the long term, the P1 protein was the better treatment used, since only the application of LLLT has not reached the same results, and these treatments applied together did not potentiate the recovery.


Asunto(s)
Terapia por Luz de Baja Intensidad , Nervio Ciático/efectos de los fármacos , Nervio Ciático/lesiones , Animales , Hevea/química , Látex/administración & dosificación , Látex/química , Masculino , Compresión Nerviosa , Proteínas de Plantas/administración & dosificación , Proteínas de Plantas/química , Proteínas de Plantas/aislamiento & purificación , Ratas , Ratas Wistar , Nervio Ciático/efectos de la radiación , Nervio Ciático/ultraestructura
11.
Lasers Med Sci ; 28(3): 777-83, 2013 May.
Artículo en Inglés | MEDLINE | ID: mdl-22797825

RESUMEN

Low-level laser therapy (LLLT) has been widely used in the treatment of the stomatognathic system dysfunction; however, its biological effect remains poorly understood. This study evaluated the effect of LLLT (GaAlAs, 780 nm, 20 J/cm(2), 40 mW) on masseter muscle of HRS/J mice after different numbers of laser irradiations (three, six, and ten) for 20 s in alternate days. Three experimental groups were defined according to the number of laser irradiations and three control groups (n=5) were used. On the third day after the last irradiation, all animals were killed and the masseter muscle was removed and processed for the following analysis: (a) transmission electron microscopy, (b) zymography, (c) immunohistochemistry for vascular endothelial growth factor (VEGF) and VEGFR-2. The results showed: (a) with six laser applications, a dilation of T tubules, and sarcoplasmic reticulum cistern, increased pinocytosed vesicles in the endothelium; with ten laser applications, few pinocytic vesicles in the endothelium and condensed mitochondria. (b) Under the conditions of this study, the synthesis of other matrix metalloproteinases was not observed, only the MMP-2 and -9. (c) After ten laser irradiations, immunostaining was observed only for VEGFR-2. We conclude that after six laser applications, ultrastructural changes may facilitate the Ca(+2) transfer to cytosol and increase the fluid transport from one surface to another. The ultrastructural changes and no immunostaining for VEGF with ten applications may decrease the metabolic activity as well as damage the angiogenic process, suggesting that an effective number of laser applications may be less than ten, associating to this therapy a better cost-benefit.


Asunto(s)
Terapia por Luz de Baja Intensidad , Músculo Masetero/efectos de la radiación , Animales , Humanos , Masculino , Músculo Masetero/metabolismo , Músculo Masetero/ultraestructura , Metaloproteinasa 2 de la Matriz/metabolismo , Metaloproteinasa 9 de la Matriz/metabolismo , Ratones , Ratones Pelados , Microscopía Electrónica de Transmisión , Modelos Animales , Trastornos de la Articulación Temporomandibular/radioterapia , Factor A de Crecimiento Endotelial Vascular/metabolismo , Receptor 2 de Factores de Crecimiento Endotelial Vascular/metabolismo
12.
Photomed Laser Surg ; 28 Suppl 2: S31-5, 2010 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-20932186

RESUMEN

OBJECTIVE: This study evaluated with histochemical analysis how the number of laser applications can affect the masseter muscle. BACKGROUND: In dentistry today, the laser is used in patients with temporomandibular disorders (TMDs), mainly for radiating pain in the masticatory muscles, whose origins may be associated with malocclusion, although the laser effects are not well understood on the cellular level. MATERIALS AND METHODS: Thirty mice (HRS/J lineage) were randomly distributed into groups according to the number of laser applications (three, six, and 10). For each group of laser applications (experimental, n = 5), it was considered the control group (n = 5), which was not irradiated. All animals inhaled halothane (2-bromo-2-chloro-1, 1, 1-trifluoroethane, minimum 99%, Sigma Aldrich, India) before each laser irradiation performed on the left masseter muscle region, on alternate days with 20 J/cm(2), 40 mW, for 20 sec. The muscle samples were collected for histochemical analysis with succinate dehydrogenase (SDH) enzyme 72 h after the last application. RESULTS: (a) A decrease in area of light fibers type (35.91% ± 6.9%; 32.08% ± 6.3%, and 27.88% ± 6.3%), according to the increase of laser applications (p < 0.05); (b) significant increase (p < 0.05) in the area of intermediate fibers, with an increase of laser application (11.08% ± 3.9%; 16.52% ± 5.7%, and 15.96% ± 3.9%), although the increase with 10 applications was small; (c) area increase of dark fibers in the group with three laser applications (0.16% ± 0.3%) (p < 0.05), and in groups with six and 10 laser applications, respectively (9.68% ± 6.0% and 9.60% ± 4.0%). CONCLUSIONS: The SDH enzyme activity revealed that the number of laser applications increases the metabolic pattern of the muscle fibers. A minimal difference in metabolic activity between six and 10 applications of a laser suggests that further analyses should be done to confirm that six applications are enough to produce the same clinical effects, thereby contributing data to professionals from different fields in regard to the cost-benefit ratio of this therapy.


Asunto(s)
Terapia por Luz de Baja Intensidad , Músculo Masetero/efectos de la radiación , Fibras Musculares Esqueléticas/efectos de la radiación , Animales , Masculino , Músculo Masetero/metabolismo , Ratones , Ratones Pelados , Fibras Musculares Esqueléticas/metabolismo , Retratamiento , Succinato Deshidrogenasa/metabolismo
13.
Micron ; 40(4): 413-8, 2009 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-19269186

RESUMEN

Low level laser therapy (LLLT) is known for its positive results but studies on the biological and biomodulator characteristics of the effects produced in the skeletal muscle are still lacking. In this study the effects of two laser dosages, 5 or 10 J/cm(2), on the lesioned tibial muscle were compared. Gerbils previously lesioned by 100 g load impact were divided into three groups: GI (n=5) controls, lesion non-irradiated; GII (n=5), lesion irradiated with 5 J/cm(2) and GIII (n=5), lesion irradiated with 10 J/cm(2), and treated for 7 consecutive days with a laser He-Ne (lambda=633 nm). After intracardiac perfusion, the muscles were dissected and reduced to small fragments, post-fixed in 1% osmium tetroxide, dehydrated in increasing alcohol concentrations, treated with propylene oxide and embedded in Spurr resin at 60 degrees C. Ultrafine cuts examined on a transmission electron microscope (Jeol 1010) revealed in the control GI group a large number of altered muscle fibers with degenerating mitochondria, intercellular substance containing degenerating cell fragments and budding blood capillaries with underdeveloped endothelial cells. However, groups GII and GIII showed muscle fibers with few altered myofibrils, regularly contoured mitochondria, ample intermembrane spaces and dilated mitochondrial crests. The clean intercellular substance showed numerous collagen fibers and capillaries with multiple abluminal processes, intraluminal protrusions and several pinocytic vesicles in endothelial cells. It was concluded that laser dosages of 5 or 10 J/cm(2) delivered by laser He-Ne (lambda=633 nm) during 7 consecutive days increase mitochondrial activity in muscular fibers, activate fibroblasts and macrophages and stimulate angiogenesis, thus suggesting effectivity of laser therapy under these experimental conditions.


Asunto(s)
Terapia por Luz de Baja Intensidad , Músculo Esquelético/lesiones , Músculo Esquelético/efectos de la radiación , Animales , Fibroblastos/efectos de la radiación , Gerbillinae , Macrófagos/efectos de la radiación , Microscopía Electrónica de Transmisión , Mitocondrias/efectos de la radiación , Fibras Musculares Esqueléticas/efectos de la radiación , Músculo Esquelético/ultraestructura , Neovascularización Fisiológica/efectos de la radiación , Manejo de Especímenes/métodos
14.
Braz Dent J ; 19(1): 57-61, 2008.
Artículo en Inglés | MEDLINE | ID: mdl-18438561

RESUMEN

Er:YAG laser has been studied as a potential tool for restorative dentistry due to its ability to selectively remove oral hard tissue with minimal or no thermal damage to the surrounding tissues. The purpose of this study was to evaluate in vitro the tensile bond strength (TBS) of an adhesive/composite resin system to human enamel surfaces treated with 37% phosphoric acid, Er:YAG laser (lambda=2.94 microm) with a total energy of 16 J (80 mJ/pulse, 2Hz, 200 pulses, 250 ms pulse width), and Er:YAG laser followed by phosphoric acid etching. Analysis of the treated surfaces was performed by scanning electron microscopy (SEM) to assess morphological differences among the groups. TBS means (in MPa) were as follows: Er:YAG laser + acid (11.7 MPa) > acid (8.2 MPa) > Er:YAG laser (6.1 MPa), with the group treated with laser+acid being significantly from the other groups (p=0.0006 and p= 0.00019, respectively). The groups treated with acid alone and laser alone were significantly different from each other (p=0.0003). The SEM analysis revealed morphological changes that corroborate the TBS results, suggesting that the differences in TBS means among the groups are related to the different etching patterns produced by each type of surface treatment. The findings of this study indicate that the association between Er:YAG laser and phosphoric acid can be used as a valuable resource to increase bond strength to laser-prepared enamel.


Asunto(s)
Grabado Ácido Dental/métodos , Recubrimiento Dental Adhesivo , Esmalte Dental/ultraestructura , Grabado Dental/métodos , Materiales Dentales/química , Láseres de Estado Sólido/uso terapéutico , Ácidos Fosfóricos/química , Bisfenol A Glicidil Metacrilato/química , Resinas Compuestas/química , Esmalte Dental/efectos de la radiación , Recubrimientos Dentinarios/química , Humanos , Ensayo de Materiales , Microscopía Electrónica de Rastreo , Estrés Mecánico , Temperatura , Resistencia a la Tracción , Factores de Tiempo , Agua/química
15.
Braz. dent. j ; 19(1): 57-61, 2008. graf, ilus
Artículo en Inglés | LILACS | ID: lil-481129

RESUMEN

Er:YAG laser has been studied as a potential tool for restorative dentistry due to its ability to selectively remove oral hard tissue with minimal or no thermal damage to the surrounding tissues. The purpose of this study was to evaluate in vitro the tensile bond strength (TBS) of an adhesive/composite resin system to human enamel surfaces treated with 37 percent phosphoric acid, Er:YAG laser (lambda=2.94 mum) with a total energy of 16 J (80 mJ/pulse, 2Hz, 200 pulses, 250 ms pulse width), and Er:YAG laser followed by phosphoric acid etching. Analysis of the treated surfaces was performed by scanning electron microscopy (SEM) to assess morphological differences among the groups. TBS means (in MPa) were as follows: Er:YAG laser + acid (11.7 MPa) > acid (8.2 MPa) > Er:YAG laser (6.1 MPa), with the group treated with laser+acid being significantly from the other groups (p=0.0006 and p= 0.00019, respectively). The groups treated with acid alone and laser alone were significantly different from each other (p=0.0003). The SEM analysis revealed morphological changes that corroborate the TBS results, suggesting that the differences in TBS means among the groups are related to the different etching patterns produced by each type of surface treatment. The findings of this study indicate that the association between Er:YAG laser and phosphoric acid can be used as a valuable resource to increase bond strength to laser-prepared enamel.


A tecnologia a laser tem sido estudada como uma ferramenta potencial para uso em odontologia devido à sua habilidade em remover tecido ósseo com um mínimo ou nenhum dano aos tecidos vizinhos. O objetivo deste estudo é comparar in vitro a resistência à tração do sistema adesivo em esmalte tratado com ácido fosfórico a 37 por cento, laser Er:YAG (lambda=2,94 mim) com energia total de 16 J (80 mJ/pulso, 2 Hz, 200 pulsos e largura de pulso de 250 ms) e com a combinação laser Er:YAG seguido por ácido fosfórico. O teste de resistência à tração foi usado para comparar a resistência à tração em cada grupo. Foi também realizada microscopia eletrônica de varredura para permitir a análise das diferenças morfológicas entre os grupos. Foram obtidos os seguintes valores médios de resistência para os grupos tratados com: laser (6,1 MPa), ácido fosfórico (8,2 MPa) e laser mais ácido (11,7 Mpa). Amostras tratadas com laser e ácido apresentaram valores maiores de resistência do que amostras com laser ou ácido isoladamente. A análise da microscopia eletrônica revelou diferenças que corroboram os resultados, demonstrando que diferenças de resistência entre os grupos são devidas às diferenças entre os padrões superficiais resultantes. Nossos resultados sugerem que a combinação do laser Er:YAG com ácido fosfórico pode ser usada como um método para aumentar a resistência à tração do sistema esmalte resina.


Asunto(s)
Humanos , Grabado Ácido Dental/métodos , Recubrimiento Dental Adhesivo , Esmalte Dental/ultraestructura , Grabado Dental/métodos , Materiales Dentales/química , Láseres de Estado Sólido/uso terapéutico , Ácidos Fosfóricos/química , Bisfenol A Glicidil Metacrilato/química , Resinas Compuestas/química , Esmalte Dental/efectos de la radiación , Recubrimientos Dentinarios/química , Ensayo de Materiales , Microscopía Electrónica de Rastreo , Estrés Mecánico , Temperatura , Resistencia a la Tracción , Factores de Tiempo , Agua/química
16.
J Clin Laser Med Surg ; 22(1): 43-50, 2004 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-15117486

RESUMEN

OBJECTIVE: Several reports have demonstrated the advantages of using the Nd:YAG laser to reduce dentin permeability by melting the dentin surface. A comparative study using different pulse durations can be useful to obtain further information about the laser-hard tissue interaction. MATERIALS AND METHODS: The present study pursues the evaluation of the morphological and chemical changes in human dentin surface resulting from Nd:YAG laser (lambda = 1064 nm) irradiation, with a total energy of 0.9 J distributed in 1, 2, 3, and 6 pulses with different pulse durations to promote surface melting and dentinal tubule occlusion. After irradiation, the samples were submitted to scanning electron microscopy (SEM) analysis for morphological study and energy-dispersive spectrometry (EDS) analysis for evaluation of the concentration of calcium and phosphorous in the melted layer. RESULTS: SEM analysis of the irradiated dentin surface showed surface structural changes due to laser irradiation, where the morphological changes are dependent on the laser pulse duration. EDS analysis showed an increase of calcium and phosphorous concentrations after Nd:YAG laser exposure, but no correlation with the number of pulses or pulse duration was found. CONCLUSION: Our results suggest that longer interaction times resulted in more evident effects with more melted substrate than shorter pulses, and in both cases the resultant melted layer contains a greater concentration of inorganic substances than non-irradiated dentin.


Asunto(s)
Dentina/efectos de la radiación , Rayos Láser , Calcio/análisis , Dentina/química , Dentina/ultraestructura , Humanos , Técnicas In Vitro , Microscopía Electrónica de Rastreo , Fósforo/análisis , Dosis de Radiación
17.
Rev. Assoc. Paul. Cir. Dent ; 48(2): 1301-7, mar.-abr. 1994. ilus, tab
Artículo en Portugués | LILACS, BBO | ID: lil-135713

RESUMEN

Foi avaliada a efetividade do jato de água-ar-pó abrasivo na reduçäo da hipersensibilidade dentinária de dentes periodontalmente envolvidos, aplicado em cinco sessöes com intervalos de 3 e 7 dias. Os resultados, avaliados clínica e morfologicamente pela microscopia eletrônica de varredura, mostraram que: o jato foi efetivo para a reduçäo da sensibilidade de grau 1 e 2, mas näo para o grau 3, com maior efetividade para o intervalo de 7 dias; a aplicaçäo do jato deixou as superfícies radiculares rugosas, com ranhuras, depressöes e escavaçöes, mais evidentes nas áreas de transiçäo cimento-esmalte e furcas


Asunto(s)
Humanos , Bicarbonatos/uso terapéutico , Sensibilidad de la Dentina/tratamiento farmacológico , Factores de Tiempo
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