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Laser Irradiation (laser + irradiation)
Kinds of Laser Irradiation Selected AbstractsCollagen Remodeling After 585-nm Pulsed Dye Laser Irradiation: An Ultrasonographic AnalysisDERMATOLOGIC SURGERY, Issue 10 2003Brent R. Moody MD Background and Objectives. Nonablative dermal remodeling is an evolving technology that has generated great interest among both laser surgeons and patients. Evidence indicates that dermal collagen formation is the key mechanism of action for the nonablative techniques. We studied, with ultrasound, new collagen formation after nonablative laser irradiation. Methods. Ten patients with facial rhytids underwent a single treatment with a 585-nm pulsed dye laser. The patients were all female, ranging in age from 47 to 67, and were Fitzpatrick skin types I,III. Laser parameters were as follows: an energy fluence of 2.4 to 3.0 J/cm2, a pulse duration of 350 ,sec, and a spot size of 5 mm with no overlap. Ultrasonographic assessments of dermal collagen were taken at baseline and at 30 and 90 days after treatment. Results. Ultrasonography demonstrated an increase in dermal collagen after a single treatment with the 585-nm pulsed dye laser. The greatest degree of neocollagenesis occurred periocularly. Conclusion. A single treatment with a 585-nm pulsed dye laser appears to increase dermal collagen. This increase in dermal collagen can be assessed with noninvasive cutaneous ultrasound. [source] Effect of Neodymium:Yttrium Aluminum Garnet Laser Irradiation on Crystallization in Li2O,Al2O3,SiO2 GlassJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 10 2001Yong Su Lee A 355-nm neodymium:yttrium aluminum garnet laser, produced by a harmonic generator, was used for the nucleation process in photosensitive glass containing Ag+ and Ce3+ ions. The pulse width and frequency of the laser were 8 ns and 10 Hz, respectively. Heat treatment was conducted at 570°C for 1 h, following laser irradiation, to produce crystalline growth, after which a LiAlSi3O8 crystal phase appeared in the laser-irradiated Li2O,Al2O3,SiO2 glass. The present study compares the effect of laser-induced nucleation on glass crystallization with that of spontaneous nucleation by heat treatment. [source] Mitochondrial Responses of Normal and Injured Human Skin Fibroblasts Following Low Level Laser Irradiation,An In Vitro StudyPHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 4 2009Innocent L. Zungu Laser irradiation has proved to be very efficient in speeding and improving the quality of healing in pathological conditions of diverse etiologies. However, the mechanisms by which the beneficial effects are attained are not clear. Mitochondria are the primary phototargets during irradiation. The study aimed to establish if laser irradiation had an effect on hypoxic and acidotic cells. The study also aimed to use existing information regarding the possible mechanism of action (established in wounded cells) and apply these principles to acidic and hypoxic irradiated cells to determine whether laser has a stimulatory or inhibitory effect. Cell cultures were modified to simulate conditions of hypoxia (hypoxic gas mixture 95% N2 and 5% O2) and acidosis (pH 6.7) whereas the central scratch model was used to simulate a wound. Cells were irradiated with a helium,neon (632.8 nm, 3 mW cm,2) laser using 5 or 16 J cm,2 on days 1 and 4. Mitochondrial responses were measured 1 or 24 h after laser irradiation by assessing changes in mitochondrial membrane potential (MMP), cyclic AMP, intracellular Ca2+ and adenosine triphosphate (ATP) cell viability. Hypoxia and acidosis significantly reduced MMP when compared with normal nonirradiated control cells. Wounded, hypoxic and acidotic cells irradiated with 5 J cm,2 showed an increase in mitochondrial responses when compared with nonirradiated cells while 16 J cm,2 showed a significant decrease. The study confirmed that laser irradiation with 5 J cm,2 stimulated an increase in intracellular Ca2+ which resulted in an increase in MMP, ATP and cAMP, which ultimately results in photobiomodulation to restore homeostasis of injured cells. [source] Effect of Low Intensity Helium,Neon (HeNe) Laser Irradiation on Experimental Paracoccidioidomycotic Wound Healing DynamicsPHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 1 2009Maria Carolina Ferreira The effect of HeNe laser on the extracellular matrix deposition, chemokine expression and angiogenesis in experimental paracoccidioidomycotic lesions was investigated. At days 7, 8 and 9 postinfection the wound of each animal was treated with a 632.8 nm HeNe laser at a dose of 3 J cm,2. At day 10 postinfection, the wounds were examined by using histologic and immunohistochemical methods. Results revealed that laser-treated lesions were lesser extensive than untreated ones, and composed mainly by macrophages and lymphocytes. High IL-1, expression was shown in the untreated group whereas in laser-treated animals the expression was scarce. On the other hand, the expression of CXCL-10 was found to be reduced in untreated animals and quite intensive and well distributed in the laser-treated ones. Also, untreated lesions presented vascular endothelial growth factor (VEGF) in a small area near the center of the lesion and high immunoreactivity for hypoxia-inducible factor-1 (HIF-1), whereas laser-treated lesions expressed VEGF surrounding blood vessels and little immunoreactivity for HIF-1. Laser-treated lesions presented much more reticular fibers and collagen deposition when compared with the untreated lesion. Our results show that laser was efficient in minimizing the local effects observed in paracoccidioidomycosis and can be an efficient tool in the treatment of this infection, accelerating the healing process. [source] Effects of Low Power Laser Irradiation on Intracellular Calcium and Histamine Release in RBL-2H3 Mast CellsPHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 4 2007Wen-Zhong Yang Although laser irradiation has been reported to promote skin wound healing, the mechanism is still unclear. As mast cells are found to accumulate at the site of skin wounds we hypothesized that mast cells might be involved in the biological effects of laser irradiation. In this work the mast cells, RBL-2H3, were used in vitro to investigate the effects of laser irradiation on cellular responses. After laser irradiation, the amount of intracellular calcium ([Ca2+]i) was increased, followed by histamine release, as measured by confocal fluorescence microscopy with Fluo-3/AM staining and a fluorescence spectrometer with o -phthalaldehyde staining, respectively. The histamine release was mediated by the increment of [Ca2+]i from the influx of the extracellular buffer solution through the cation channel protein, transient receptor potential vanilloid 4 (TRPV4). The TRPV4 inhibitor, Ruthenium Red (RR) can effectively block such histamine release, indicating that TRPV4 was the key factor responding to laser irradiation. These induced responses of mast cells may provide an explanation for the biological effects of laser irradiation on promoting wound healing, as histamine is known to have multi-functions on accelerating wound healing. [source] Removal of gutta-percha from root canals using an Nd:YAG laserINTERNATIONAL ENDODONTIC JOURNAL, Issue 10 2003D. Vidu Abstract Aim, To examine the use of an Nd:YAG laser in removing gutta-percha fillings from root canals when used in conjunction with eucalyptol, dimethylformamide (DMF) or no solvent. Methodology, Root-canal fillings (sealer and gutta-percha) were removed with laser irradiation of 20 Hz/1.5 W from 30 roots randomly divided in three groups. In group 1, the solvent was eucalyptol; in group 2, the solvent was DMF; and in group 3, no solvent was used. Laser irradiation was performed until the temperature measured on the root surface increased by 4 °C over room temperature. The treatment was deemed complete when the apical foramen was reached with the optical fibre and a reamer. The samples were split longitudinally, and the area of remaining gutta-percha on the root-canal walls was determined with the aid of a computer program. The total number of laser pulses to achieve length and the highest temperature recorded was determined for each tooth. The results were statistically analysed using Student's t -test (P < 0.05) for independent samples. Results, The average temperature increase in group 1 was 9.17 ± 0.56 °C; in group 2, 9.56 ± 0.28 °C; and in group 3, 8.29 ± 0.41 °C. The shortest time to achieve length was in group 3 (6.4 ± 0.49 min), then in group 1 (6.7 ± 0.85 min) and group 2 (7.05 ± 0.79 min). The area of remaining gutta-percha was the largest in group 2 (6.13 ± 5.76%), whilst the smallest was for group 3 (4.69 ± 4.03%), but the difference was not statistically significant. The number of pulses was not statistically significant between the groups. Conclusions, Use of an Nd:YAG laser alone is capable of softening gutta-percha. The addition of solvents did not improve the retreatment, either in terms of the time required for the procedure or in terms of the area of remaining gutta-percha on root-canal walls. [source] Effect of Er:YAG laser and EDTAC on the adhesiveness to dentine of different sealers containing calcium hydroxideINTERNATIONAL ENDODONTIC JOURNAL, Issue 7 2003F. Picoli Abstract Aim, To evaluate the effect of 15% EDTAC solution and Er:YAG laser irradiation on the adhesiveness to dentine of root canal sealers containing calcium hydroxide. Methodology, The crowns of 60 maxillary human molars were ground until dentine was exposed. The teeth were divided into three groups of 20 teeth: group I, the dentine surface received no treatment; group II, 15% EDTAC solution was applied to the dentine; group III, the dentine received Er:YAG laser application (11 mm focal distance with perpendicular incidence to dentine surface; 4 Hz frequency; 200 mJ energy; 2.25 W potency; 62 J total energy; 1 min application time). Aluminium cylinders filled with the sealers, Sealer 26, Apexit, Sealapex and CRCS, were then applied to the treated surfaces. Adhesiveness was measured with a universal testing machine, with traction results given in MegaPascals (MPa). These results were submitted to anova tests. Results, Statistical analysis showed significant differences (P < 0.01) amongst adhesiveness values of the sealers and treatments tested. Thus, sealers could be ranked in decreasing adhesiveness values: Sealer 26, CRCS, Apexit, Sealapex. Er:YAG laser irradiation and EDTAC solution application increased adhesiveness values only for Sealer 26 and Apexit. Laser irradiation was superior to EDTAC application only for Sealer 26 adhesiveness values. Conclusions, Er:YAG laser is as efficient as EDTAC solution in increasing adhesiveness of root canal sealers containing calcium hydroxide to human dentine. [source] In vitro evaluation of Er:YAG laser scaling of subgingival calculus in comparison with ultrasonic scalingJOURNAL OF PERIODONTAL RESEARCH, Issue 5 2000A. Aoki The purpose of the present study was to evaluate the effectiveness of Er:YAG laser scaling and the morphological and histological changes of the laser-scaled root surface in comparison with the effectiveness and root surface changes produced by conventional ultrasonic scaling. Fifty-three periodontally involved human extracted teeth with a band of subgingival calculus were used. The teeth were divided randomly into 2 groups for laser scaling and ultrasonic scaling. Laser irradiation was performed at an energy output of 40 mJ/pulse and 10 pulses/s under water spray, with the probe tip contacted obliquely to the root surface. Ultrasonic scaling was performed at a clinically standard power setting. The time required for scaling, the scaled area and the temperature changes were determined using both methods of treatment. The features of the scaled surfaces were examined by histological and scanning electron microscope (s.e.m.) observations. The Er:YAG laser provided subgingival calculus removal on a level equivalent to that provided by the ultrasonic scaler, without major thermal elevation. Macroscopically, the laser-treated root surface was somewhat rougher than or similar to the ultrasonically scaled root. However, the efficiency of the laser scaling was lower than that of the ultrasonic scaling. In addition, histological examination revealed a thin deeply stained zone on the lased root surface, and s.e.m. analysis revealed a characteristic microroughness on the lased surface. The laser scaling provided a level of calculus removal that was similar to that provided by the ultrasonic scaling. However, the Er:YAG laser produced superficial, structural and thermal microchanges on the root cementum. [source] Micromorphology of resin,dentin interfaces using one-bottle etch&rinse and self-etching adhesive systems on laser-treated dentin surfaces: A confocal laser scanning microscope analysisLASERS IN SURGERY AND MEDICINE, Issue 7 2010Marcelo Tavares de Oliveira DDS Abstract Background and Objectives This study evaluated the hybrid layer (HL) morphology created by three adhesive systems (AS) on dentin surfaces treated with Er:YAG laser using two irradiation parameters. Study Design Occlusal flat dentin surfaces of 36 human third molars were assigned into nine groups (n,=,4) according to the following ASs: one bottle etch&rinse Single Bond Plus (3M ESPE), two-step Clearfil Protect Bond (Kuraray), and all-in-one S3 Bond (Kuraray) self-etching, which were labeled with rhodamine B or fluorescein isothiocyanate,dextran and were applied to dentin surfaces that were irradiated with Er:YAG laser at either 120 (38.7,J/cm2) or 200,mJ/pulse (64.5,J/cm2), or were applied to untreated dentin surfaces (control group). The ASs were light-activated following MI and the bonded surfaces were restored with resin composite Z250 (3M ESPE). After 24,hours of storage in vegetable oil, the restored teeth were vertically, serially sectioned into 1-mm thick slabs, which had the adhesive interfaces analyzed with confocal laser microscope (CLSM,LSM 510 Meta). CLSM images were recorded in the fluorescent mode from three different regions along each bonded interface. Results Non-uniform HL was created on laser-irradiated dentin surfaces regardless of laser irradiation protocol for all AS, while regular and uniform HL was observed in the control groups. "Stretch mark"-like red lines were found within the HL as a result of resin infiltration into dentin microfissures, which were predominantly observed in 200,mJ/pulse groups regardless of AS. Poor resin infiltration into peritubular dentin was observed in most regions of adhesive interfaces created by all ASs on laser-irradiated dentin, resulting in thin resin tags with neither funnel-shaped morphology nor lateral resin projections. Conclusion Laser irradiation of dentin surfaces at 120 or 200,mJ/pulse resulted in morphological changes in HL and resin tags for all ASs evaluated in the study. Lasers Surg. Med. 42:662,670, 2010. © 2010 Wiley-Liss, Inc. [source] Laser irradiation of the guinea pig basilar membraneLASERS IN SURGERY AND MEDICINE, Issue 3 2004Gentiana I. Wenzel MD Abstract Background and Objectives The cochlea is the part of the inner ear that transduces sound waves into neural signals. The basilar membrane, a connective tissue sheet within the cochlea, is tonotopically tuned based on the spatial variation of its mass, stiffness, and damping. These biophysical properties are mainly defined by its constituent collagen fibers. We sought to assess the effect of laser irradiation on collagen within the basilar membrane using histological analysis. Study Design/Materials and Methods Four excised guinea pig cochleae were stained with trypan blue. From these, two were irradiated with a 600 nm pulsed dye laser and two were used as controls. Collagen organization was visualized using polarization microscopy. Results Laser irradiation reduced the birefringence within the basilar membrane as well as within other stained collagen-containing structures. Larger reductions in birefringence were measured when more laser pulses were given. The effects were similar across all turns of each cochlea. Conclusions Laser irradiation causes immediate alterations in collagen organization within the cochlea that can be visualized with polarization microscopy. These alterations may affect cochlear tuning. Ongoing research is aimed at analyzing the effect of laser irradiation on cochlear function. It is conceivable that this technique may have therapeutic benefits for patients with high-frequency sensorineural hearing loss. Lasers Surg. Med. 35:174,180, 2004. © 2004 Wiley-Liss, Inc. [source] Attenuation of infarct size in rats and dogs after myocardial infarction by low-energy laser irradiationLASERS IN SURGERY AND MEDICINE, Issue 3 2001Uri Oron PhD Abstract Background and Objective The aim of the present study was to investigate the possibility that low-energy laser irradiation attenuates infarct size formation after induction of chronic myocardial infarction (MI) in small and large experimental animals. Study Design/Materials and Methods Laser irradiation was applied to the infarcted area of rats and dogs at various power densities (2.5 to 20 mW/cm2) after occlusion of the coronary artery. Results In infarcted laser-irradiated rats that received laser irradiation immediately and 3 days after MI at energy densities of 2.5, 6, and 20 mW/cm2, there was a 14%, 62% (significant; P,<,0.05), and 2.8% reduction of infarct size (14 days after MI) relative to non,laser-irradiated rats, respectively. In dogs, a 49% (significant; P,<,0.01) reduction of infarct size was achieved. Conclusion The results of the present study indicate that delivery of low-energy laser irradiation to infarcted myocardium in rats and dogs has a profound effect on the infarct size after MI. Lasers Surg. Med. 28:204,211, 2001. © 2001 Wiley-Liss, Inc. [source] Mitochondrial Responses of Normal and Injured Human Skin Fibroblasts Following Low Level Laser Irradiation,An In Vitro StudyPHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 4 2009Innocent L. Zungu Laser irradiation has proved to be very efficient in speeding and improving the quality of healing in pathological conditions of diverse etiologies. However, the mechanisms by which the beneficial effects are attained are not clear. Mitochondria are the primary phototargets during irradiation. The study aimed to establish if laser irradiation had an effect on hypoxic and acidotic cells. The study also aimed to use existing information regarding the possible mechanism of action (established in wounded cells) and apply these principles to acidic and hypoxic irradiated cells to determine whether laser has a stimulatory or inhibitory effect. Cell cultures were modified to simulate conditions of hypoxia (hypoxic gas mixture 95% N2 and 5% O2) and acidosis (pH 6.7) whereas the central scratch model was used to simulate a wound. Cells were irradiated with a helium,neon (632.8 nm, 3 mW cm,2) laser using 5 or 16 J cm,2 on days 1 and 4. Mitochondrial responses were measured 1 or 24 h after laser irradiation by assessing changes in mitochondrial membrane potential (MMP), cyclic AMP, intracellular Ca2+ and adenosine triphosphate (ATP) cell viability. Hypoxia and acidosis significantly reduced MMP when compared with normal nonirradiated control cells. Wounded, hypoxic and acidotic cells irradiated with 5 J cm,2 showed an increase in mitochondrial responses when compared with nonirradiated cells while 16 J cm,2 showed a significant decrease. The study confirmed that laser irradiation with 5 J cm,2 stimulated an increase in intracellular Ca2+ which resulted in an increase in MMP, ATP and cAMP, which ultimately results in photobiomodulation to restore homeostasis of injured cells. [source] Ultra-fast dynamics in solids: non-equilibrium behaviour of magnetism and atomic structureANNALEN DER PHYSIK, Issue 7-8 2009K.H. Bennemann Abstract Non-equilibrium physics is of fundamental interest, for example, for extensions of statistical mechanics and thermodynamics. In particular, it is important to understand how conservation laws like energy conservation and angular-momentum conservation in magnetic solids control the time scale of the dynamics. Laser irradiation may cause intense electronic excitations and thus a strong non-equilibrium state. Results are presented for the ultra-fast response of magnetism in ferromagnetic transition metals like Ni, Co, Fe, and Gd and furthermore of the atomic structure in semiconductors like Si, Ge, and InSb. Non-thermal melting is a most spectacular example of ultra-fast bond breaking. Time-resolved magnetooptical experiments yielding sub-picosecond spin dynamics are discussed. The spin dynamics is accompanied by THz light emission. The structural changes in semiconductors, bond changes sp3 , s2p2, and phase transitions occur within about 100 fs. The results also shed light on electron-transfer processes, on ionization, and on molecular dissociation dynamics, which may occur during fs and as times. We discuss the application of time-resolved analysis to tunnelling problems and the phase diagram of high-Tc superconductivity. [source] Ultra-fast dynamics in solids: non-equilibrium behaviour of magnetism and atomic structureANNALEN DER PHYSIK, Issue 7-8 2009K.H. Bennemann Abstract Non-equilibrium physics is of fundamental interest, for example, for extensions of statistical mechanics and thermodynamics. In particular, it is important to understand how conservation laws like energy conservation and angular-momentum conservation in magnetic solids control the time scale of the dynamics. Laser irradiation may cause intense electronic excitations and thus a strong non-equilibrium state. Results are presented for the ultra-fast response of magnetism in ferromagnetic transition metals like Ni, Co, Fe, and Gd and furthermore of the atomic structure in semiconductors like Si, Ge, and InSb. Non-thermal melting is a most spectacular example of ultra-fast bond breaking. Time-resolved magnetooptical experiments yielding sub-picosecond spin dynamics are discussed. The spin dynamics is accompanied by THz light emission. The structural changes in semiconductors, bond changes sp3 , s2p2, and phase transitions occur within about 100 fs. The results also shed light on electron-transfer processes, on ionization, and on molecular dissociation dynamics, which may occur during fs and as times. We discuss the application of time-resolved analysis to tunnelling problems and the phase diagram of high-Tc superconductivity. [source] Size-Selective Formation of C78 Fullerene from a Three-Dimensional Polyyne PrecursorCHEMISTRY - A EUROPEAN JOURNAL, Issue 5 2005Yoshito Tobe Prof. Dr. Abstract Multicyclic cagelike cyclophanes 2,a and 2,b containing cyclobutene rings have been prepared as precursors of three-dimensional polyynes C78H18 (1,a) and C78H12Cl6 (1,b), respectively. Laser irradiation of 2,a and 2,b induced expulsion of the aromatic fragment, indane, to give the three-dimensional polyyne anions C78H18, and C78H12Cl6,, respectively. Whereas the former anion lost only four hydrogen atoms to form C78H14,, complete loss of all hydrogen and chlorine atoms was observed from the latter anion, to yield a C78, ion that has a fullerene structure which was proven by its characteristic fragmentation pattern. [source] Minocycline-Induced Hyperpigmentation Treated with a 755-nm Q-Switched Alexandrite LaserDERMATOLOGIC SURGERY, Issue 9 2004Tina S. Alster MD Background. Cutaneous pigmentation associated with minocycline therapy is an unusual adverse effect for which few successful treatments have been described. The pigment changes may persist for years, despite cessation of therapy, and is often cosmetically disfiguring, causing significant embarrassment and psychological depression in those affected. Few safe and effective treatments have been described in the past; however, recent pigment-specific laser technology has shown promise in the treatment of this condition. Objective. The objective was to describe a series of patients with minocycline-induced hyperpigmentation who were successfully treated with a 755-nm Q-switched alexandrite laser. Methods. Six patients with minocycline-induced hyperpigmentation on the face or legs were treated with a Q-switched alexandrite laser on a bimonthly basis until pigmentation was eradicated. Results. Cutaneous pigmentation resolved completely in all patients in an average of four laser sessions. Side effects were limited to transient purpura and mild desquamation without scarring or dyspigmentation. Conclusion. Minocycline-induced cutaneous pigmentation can be effectively cleared without risk of adverse sequelae by Q-switched alexandrite (755-nm) laser irradiation. [source] Collagen Remodeling After 585-nm Pulsed Dye Laser Irradiation: An Ultrasonographic AnalysisDERMATOLOGIC SURGERY, Issue 10 2003Brent R. Moody MD Background and Objectives. Nonablative dermal remodeling is an evolving technology that has generated great interest among both laser surgeons and patients. Evidence indicates that dermal collagen formation is the key mechanism of action for the nonablative techniques. We studied, with ultrasound, new collagen formation after nonablative laser irradiation. Methods. Ten patients with facial rhytids underwent a single treatment with a 585-nm pulsed dye laser. The patients were all female, ranging in age from 47 to 67, and were Fitzpatrick skin types I,III. Laser parameters were as follows: an energy fluence of 2.4 to 3.0 J/cm2, a pulse duration of 350 ,sec, and a spot size of 5 mm with no overlap. Ultrasonographic assessments of dermal collagen were taken at baseline and at 30 and 90 days after treatment. Results. Ultrasonography demonstrated an increase in dermal collagen after a single treatment with the 585-nm pulsed dye laser. The greatest degree of neocollagenesis occurred periocularly. Conclusion. A single treatment with a 585-nm pulsed dye laser appears to increase dermal collagen. This increase in dermal collagen can be assessed with noninvasive cutaneous ultrasound. [source] Efficacy of the Flashlamp-Pumped Pulsed-Dye Laser in Nonsurgical Delay of Skin FlapsDERMATOLOGIC SURGERY, Issue 7 2003Ali Riza Erçöçen MD Objective. The purpose of this article was to determine the effectiveness of laser delay by use of the flashlamp-pumped pulsed-dye laser operating at a wavelength of 585 nm; to elucidate the comparable or dissimilar macroscopic, microscopic, and hemodynamic changes between laser and surgical delay methods; and to clarify the possible mechanisms underlying the delay effect of laser. Methods. A standardized caudally based random dorsal rat flap model was used in this study: Acute random skin flaps served as control subjects (group 1). Surgical delay was employed by incision of lateral longitudinal borders both without (group 2) and with (group 3) undermining, and laser delay methods were performed by laser irradiation of both lateral longitudinal borders (group 4) and the entire surface (group 5) of the proposed flap. Evaluation was done by histologic examination, India ink injection, laser Doppler perfusion imaging, and measurement of flap survival. Results. Histologically, dilation and hypertrophy of subpapillary and subdermal vessels were evident in groups 2, 3, and 4; on the other hand, degranulation of mast cells in the vicinity of occluded vessels at the 1st hour of laser delay and a striking mast cell proliferation and degranulation in association with newly formed vessels (angiogenesis) at the 14th day of laser delay were prominent in group 5. India ink injections revealed longitudinally arranged large-caliber vessels and cross-filling between the vessels of adjacent territories in groups, 2, 3, and 4, but only small-caliber vessels in group 5. Compared with the acute flaps, both surgical and laser delay significantly increased the mean flap perfusion to the maximal levels after a 14-day delay period, and all delay procedures improved flap survival; the most significant increase in surviving area was observed in group 3, whereas the less significant increase in surviving area was in group 5. Conclusion. This study demonstrates that laser delay is as effective as surgical delay and that laser delay by lasering lateral borders leads to dilation and longitudinal rearrangement of the existing vessels rather than angiogenesis, whereas laser delay by lasering the entire surface results in delay effect by inducing angiogenesis due to activation and degranulation of the mast cells. [source] Retinal Evaluation After 810 nm Dioderm Laser Removal of EyelashesDERMATOLOGIC SURGERY, Issue 9 2002Randal T. H. Pham MD background. When operating hair removal lasers on the face or in the periorbital region, even with an ocular shield in place, patients often report seeing "flashing lights" each time the laser is fired. This phenomenon suggests stimulation of retinal photoreceptors and raises laser safety issues. objective. To perform retinal electrophysiologic studies to evaluate the safety of hair removal lasers in the periorbital region. methods. Five patients with severe trichiasis secondary to trachoma were studied. The 810 nm Dioderm laser (Cynosure, Inc., Chelmsford, MA) was used to treat the eyelash follicles on the lower eyelid of each patient. Cox III metal eye shields (Oculo-Plastik, Inc., Montreal, Canada) were placed behind the eyelids of both eyes during the laser procedure. Prior to irradiation, a comprehensive ophthalmic evaluation including pupillary and slit-lamp examination, funduscopy, and full-field electroretinograms (ERGs) was performed. A comprehensive ophthalmic evaluation including ERG testing was repeated 30 minutes and 3,6 months after completion of treatment. An independent blinded assessor evaluated the ERG studies. Subjective reports of laser light sensation, pain, and discomfort during and after the laser procedure were also assessed. results. There was no detectable change in slit-lamp, pupillary, or funduscopic evaluations after periorbital laser irradiation. Similarly the pre- and posttreatment ERGs were unchanged. Three patients reported seeing flashing lights during the procedure. conclusion. We found no ERG evidence of retinal damage after laser hair removal in the periorbital region, with Cox III-type ocular shields over the eyes, even when patients subjectively reported "flashing lights" during laser irradiation. [source] Carbon Nanotubes on Polymeric Microcapsules: Free-Standing Structures and Point-Wise Laser OpeningsADVANCED FUNCTIONAL MATERIALS, Issue 18 2010Alexey M. Yashchenok Abstract Single-wall carbon nanotubes modified by anionic polyelectrolyte molecules are embedded into the shells of microcapsules. Carbon nanotubes serve as rigid rods in a softer polymeric capsule, which forms a free-standing shell upon treatment with glutaraldehyde and subsequent drying. The embedded carbon nanotubes exhibit a broad absorption in the UV,near-infrared part of the spectrum, and that allows point-wise activation and opening of the microcapsules by laser. Raman signal analysis shows changes of carbon-nanotube-specific lines after high-power laser irradiation, which is characteristic of the formation of disordered carbonlike structures. These polyelectrolyte/carbon nanotube composite capsules represent a novel light-addressable type of microcontainers. [source] Bond strength of AH Plus and Epiphany sealers on root dentine irradiated with 980 nm diode laserINTERNATIONAL ENDODONTIC JOURNAL, Issue 9 2008E. Alfredo Abstract Aim, To evaluate the bond strength of AH Plus and Epiphany sealers to human root canal dentine irradiated with a 980 nm diode laser at different power and frequency parameters, using the push-out test. Methodology, Sixty canine roots were sectioned below the cementoenamel junction to provide 4-mm-thick dentine discs that had their root canals prepared with a tapered bur and irrigated with sodium hypochlorite, ethylenediaminetetraacetic acid and distilled water. The specimens were assigned to five groups (n = 12): one control (no laser) and four experimental groups that were submitted to 980 nm diode laser irradiation at different power (1.5 and 3.0 W) and frequency (continuous wave and 100 Hz) parameters. Half of specimens in each group had their canals filled with AH Plus sealer and half with Epiphany. The push-out test was performed and data (MPa) were analysed statistically by anova and Tukey's test (P < 0.05). The specimens were split longitudinally and examined under SEM to assess the failure modes after sealer displacement. Results, The specimens irradiated with the diode laser and filled with AH Plus had significantly higher bond strength values (8.69 ± 2.44) than those irradiated and filled with Epiphany (3.28 ± 1.58) and the nonirradiated controls (3.86 ± 0.60). The specimens filled with Epiphany did not differ significantly to each other or to the control (1.75 ± 0.69). There was a predominance of adhesive failures at Epiphany,dentine interface (77%) and mixed failures at AH Plus,dentine interface (67%). Conclusions, The 980 nm diode laser irradiation of root canal dentine increased the bond strength of AH Plus sealer, but did not affect the adhesion of Epiphany sealer. [source] Removal of gutta-percha from root canals using an Nd:YAG laserINTERNATIONAL ENDODONTIC JOURNAL, Issue 10 2003D. Vidu Abstract Aim, To examine the use of an Nd:YAG laser in removing gutta-percha fillings from root canals when used in conjunction with eucalyptol, dimethylformamide (DMF) or no solvent. Methodology, Root-canal fillings (sealer and gutta-percha) were removed with laser irradiation of 20 Hz/1.5 W from 30 roots randomly divided in three groups. In group 1, the solvent was eucalyptol; in group 2, the solvent was DMF; and in group 3, no solvent was used. Laser irradiation was performed until the temperature measured on the root surface increased by 4 °C over room temperature. The treatment was deemed complete when the apical foramen was reached with the optical fibre and a reamer. The samples were split longitudinally, and the area of remaining gutta-percha on the root-canal walls was determined with the aid of a computer program. The total number of laser pulses to achieve length and the highest temperature recorded was determined for each tooth. The results were statistically analysed using Student's t -test (P < 0.05) for independent samples. Results, The average temperature increase in group 1 was 9.17 ± 0.56 °C; in group 2, 9.56 ± 0.28 °C; and in group 3, 8.29 ± 0.41 °C. The shortest time to achieve length was in group 3 (6.4 ± 0.49 min), then in group 1 (6.7 ± 0.85 min) and group 2 (7.05 ± 0.79 min). The area of remaining gutta-percha was the largest in group 2 (6.13 ± 5.76%), whilst the smallest was for group 3 (4.69 ± 4.03%), but the difference was not statistically significant. The number of pulses was not statistically significant between the groups. Conclusions, Use of an Nd:YAG laser alone is capable of softening gutta-percha. The addition of solvents did not improve the retreatment, either in terms of the time required for the procedure or in terms of the area of remaining gutta-percha on root-canal walls. [source] Effect of Er:YAG laser and EDTAC on the adhesiveness to dentine of different sealers containing calcium hydroxideINTERNATIONAL ENDODONTIC JOURNAL, Issue 7 2003F. Picoli Abstract Aim, To evaluate the effect of 15% EDTAC solution and Er:YAG laser irradiation on the adhesiveness to dentine of root canal sealers containing calcium hydroxide. Methodology, The crowns of 60 maxillary human molars were ground until dentine was exposed. The teeth were divided into three groups of 20 teeth: group I, the dentine surface received no treatment; group II, 15% EDTAC solution was applied to the dentine; group III, the dentine received Er:YAG laser application (11 mm focal distance with perpendicular incidence to dentine surface; 4 Hz frequency; 200 mJ energy; 2.25 W potency; 62 J total energy; 1 min application time). Aluminium cylinders filled with the sealers, Sealer 26, Apexit, Sealapex and CRCS, were then applied to the treated surfaces. Adhesiveness was measured with a universal testing machine, with traction results given in MegaPascals (MPa). These results were submitted to anova tests. Results, Statistical analysis showed significant differences (P < 0.01) amongst adhesiveness values of the sealers and treatments tested. Thus, sealers could be ranked in decreasing adhesiveness values: Sealer 26, CRCS, Apexit, Sealapex. Er:YAG laser irradiation and EDTAC solution application increased adhesiveness values only for Sealer 26 and Apexit. Laser irradiation was superior to EDTAC application only for Sealer 26 adhesiveness values. Conclusions, Er:YAG laser is as efficient as EDTAC solution in increasing adhesiveness of root canal sealers containing calcium hydroxide to human dentine. [source] Calculated spectral properties of perylene orange, perylene red, and their complex with sodium azideINTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, Issue 13 2007Anuar Aldongarov Abstract Using the method of density functional theory in approximating B3LYP with the basis set 6-31G(d) the computations of structures of the following dyes 2,2,- N - N,-di(1,3-diisopropylbenzene)-diimide 3,4,9,10-perylenetethracarbon acid (Perylene Orange-PO) and 1,6,7,12-tethraphenyl ether 2,2,- N,N,-di(1,3-diisopropylbenzene)-diimide 3,4,9,10-perylenetethracarbon acid (Perylene Red-PR) were performed. It was revealed that PO and PR have nonplanar structures. On the basis of the predicted geometrical structures and molecular orbitals of S0 ground state their theoretical UV-vis spectra, which are in good agreement with experiment, were obtained by applying time-dependent DFT (TDDFT) method. In addition, the calculations of complex [PR , NaN3] and its UV-vis spectrum, which was compared with the observed electron spectrum of PR ethanol solution in the presence of NaN3 under the laser irradiation at 532 nm, were carried out. By using DFT method at B3LYP level the calculations of the assumed complex were made where the reaction coordinate was the distance between Na+ and carbonyl group O atom. It was suggested that [PR , NaN3] complex formation involves transition of PR to the triplet state which brings about formation of PR anion. New peak at 793 nm in UV-vis spectrum of this solution under the laser irradiation at 532 nm is supposed to be a PR anion band. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2007 [source] Degradation behavior of nanoreinforced epoxy systems under pulse laserJOURNAL OF APPLIED POLYMER SCIENCE, Issue 5 2009M. Calhoun Abstract Nanocomposites using EPON 824 as their matrix were exposed to pulse laser at 532 nm for various time intervals. The developed nanomaterials used for this study were manufactured using EPON 824 with multiwalled carbon nanotubes (MWCNTs) at a loading rate of 0.15% by weight and nanoclays at a loading rate of 2% by weight as reinforcements. The effect of laser irradiation on polymer composites has been investigated. The degradation mechanism for the epoxy was of a laser induced burning nature. Of all specimens tested, the ultimate strength of the MWCNT-reinforced specimens decreased the most as a function of radiation time; the nanoclay-reinforced epoxy retained the most strength after 2 min of laser radiation. In addition, the threshold fluence for decomposition indicated that less energy was required to initiate decomposition in the MWCNT-reinforced epoxy than in the nanoclay-reinforced epoxy. This can be attributed to the high thermal conductivity of the carbon nanotubes. Measurement of surface damage in the material was observed via electron microscopy. Fourier transform infrared spectroscopy was used to investigate changes to the molecular structure as a function of exposure time. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 [source] Adhesion of a self-etching system to dental substrate prepared by Er:YAG laser or air abrasionJOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 2 2008Wanessa C. Souza-Zaroni Abstract The purpose of this study was to assess the microtensile bond strength of a self-etching adhesive system to enamel and dentin prepared by Er:YAG laser irradiation or air abrasion, as well as to evaluate the adhesive interfaces by scanning electron microscopy (SEM). For microtensile bond strength test, 80 third molars were randomly assigned to five groups: Group I, carbide bur, control (CB); II, air abrasion with standard tip (ST); III, air abrasion with supersonic tip (SP); IV, Er:YAG laser 250 mJ/4 Hz (L250); V, Er:YAG laser 300 mJ/4 Hz (L300). Each group was divided into two subgroups (n = 8) (enamel, E and dentin, D). E and D surfaces were treated with the self-etching system Adper Prompt L-Pop and composite buildups were done with Filtek Z-250. Sticks with a cross-sectional area of 0.8 mm2 (±0.2 mm2) were obtained and the bond strength tests were performed. Data were submitted to ANOVA and Tukey's test. For morphological analysis, disks of 30 third molars were restored, sectioned and prepared for SEM. Dentin presented the highest values of adhesion, differing from enamel. Laser and air-abrasion preparations were similar to enamel. Dentin air-abrasion with standard tip group showed higher bond strength results than Er:YAG-laser groups, however, air-abrasion and Er:YAG laser groups were similar to control group. SEM micrographs revealed that, for both enamel and dentin, the air-abrasion and laser preparations presented irregular adhesive interfaces, different from the ones prepared by rotary instrument. It was concluded that cavity preparations accomplished by both Er:YAG laser energies and air abrasion tips did not positively influence the adhesion to enamel and dentin. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2008 [source] Cover Picture: J. Biophoton.JOURNAL OF BIOPHOTONICS, Issue 4 20104/2010 Glass substrate after femtosecond laser irradiation of six devices that will be obtained by six cuts along the transversal straight lines and a further orthogonal one. Chemical etching will create micro-channels where the more complex structures have been irradiated, while not affecting the inscribed optical waveguides. The devices will then be used for optical trapping and stretching of cells. (Picture: F. Bragheri et al., pp. 234,243 in this issue) [source] Improved wound healing by low-level laser irradiation after gingivectomy operations: a controlled clinical pilot studyJOURNAL OF CLINICAL PERIODONTOLOGY, Issue 3 2008Onur Ozcelik Abstract Aim: Low-level laser therapy (LLLT) may induce morphological, molecular and cellular processes, which are involved in wound healing. The aim of this split-mouth controlled clinical trial was to assess the effects of LLLT on healing of gingiva after gingivectomy and gingivoplasty. Material and Methods: Twenty patients with inflammatory gingival hyperplasias on their symmetrical teeth were included in this study. After gingivectomy and gingivoplasty, a diode laser (588 nm) was randomly applied to one side of the operation area for 7 days. The surgical areas were disclosed by a solution (Mira-2-tones) to visualize the areas in which the epithelium is absent. Comparison of the surface areas on the LLLT-applied sites and controls were made with an image-analysing software. Results: Despite the prolonged time needed for application, patients have tolerated LLLT well. While there were no statistically significant differences between the stained surface areas of the LLLT applied and the control sites immediately after the surgery, LLLT-applied sites had significantly lower stained areas compared with the controls on the post-operative third, seventh and 15th day (p<0.001 for each). Conclusions: Within the limitations of this study, the results indicated that LLLT may enhance epithelization and improve wound healing after gingivectomy and gingivoplasty operations. [source] Root surface roughness following Er:YAG laser irradiation at different radiation energies and working tip angulationsJOURNAL OF CLINICAL PERIODONTOLOGY, Issue 7 2002Matthias Folwaczny Abstract Objectives: The determination of roughness of root surfaces following treatment with 2.94 µm Er:YAG laser radiation at different radiation energies and working tip angulations. Materials and methods: The study sample comprised 85 extracted human molars, premolars, canines and incisors (n = 85). The source of laser radiation was an Er:YAG laser device (KAVO-Key II, System Aesculap Meditec) emitting pulsed infrared radiation at a wavelength of 2.94 µm, with a pulse duration of 250 µs, and a pulse repetition rate of 10 pps. The samples were randomly divided into three experimental units, for treatment with a constant amount of 380 laser pulses at a radiation energy of 60 mJ, 100 mJ, and 180 mJ. Each experimental unit was divided into five subgroups of five samples, which were irradiated at a working tip angulations of 15°, 30°, 45°, 60°, and 90°. Five samples were treated mechanically using curettes. Five samples were left untreated as control. The mean (Ra) and maximum (Rmax) surface roughness of each sample was measured using a profilometer. The statistical analysis was undertaken using anova and Scheffé-test at a level of significance of 5% (p < 0.05). Results: Er:YAG laser radiation led to an Ra which ranged from 0.52 µm (± 0.10) to 0.81 µm (± 0.26) and to an Rmax between 3.4 µm (± 0.48) and 9.26 µm (± 3.08). The Ra and Rmax for samples treated with curettes was 0.51 µm (± 0.11) and 5.08 µm (± 4.98), respectively. That for the untreated control samples were 0.53 µm (± 0.15) and 7.07 µm (± 5.48), respectively. Conclusions: The mean and maximum surface roughness of root surfaces following irradiation with Er:YAG laser was not significantly different to that obtained on samples treated with conventional hand instruments or left untreated. Furthermore, the surface roughness does not depend on the radiation energy and the angulation of the working tip. [source] Morphology, chemical structure and diffusion processes of root surface after Er:YAG and Nd:YAG laser irradiationJOURNAL OF CLINICAL PERIODONTOLOGY, Issue 6 2001B. Ga Abstract Objectives: The aim of this in vitro study was to evaluate the effects of Er:YAG and Nd:YAG lasers on morphology, chemical structure and diffusion processes of the root surface. Material and methods: 60 root samples were irradiated for 1 min each either with 60 mJ/p, 80mJ/p and 100mJ/p using Er:YAG laser or with 0.5W, 1.0W and 1.5W using Nd:YAG laser. Scanning electron microscopy (SEM) was used to determine the morphology, infrared (IR) spectroscopy to assess the alterations in chemical structure and one dimensional electron paramagnetic resonance imaging (1-D EPRI) was used to estimate the diffusion coefficients in dental root samples. Results: Er:YAG laser treatment resulted in deep crater formation with exposed dentin. Morphological alterations of root surface after Nd:YAG laser irradiation included cracks, crater formation, meltdown of the root mineral and resolidified porous globules formation. Er:YAG laser failed to alter the intensity of Amide peaks I, II or III. In contrast, treatment with Nd:YAG laser, using the highest power setting of 1.5W, reduced the intensity of Amide peak II and III in comparison to the control. The diffusion coefficients were increased significantly in all Er:YAG and Nd:YAG treated root samples. Conclusion: This study demonstrated that Er:YAG laser influences only on morphology and diffusion processes of root surfaces, while Nd:YAG laser also alters the chemical structure of root proteins. Zusammenfassung Ziele: Das Ziel dieser in vitro Studie war es, die Wirkung von Er:YAG- und Nd:YAG-Laser auf die Morphologie, chemische Struktur und die Diffusionsprozesse zu evaluieren. Material und Methoden: 60 Proben von Wurzeln wurden für eine Minute entweder mit einem Er:YAG-Laser und 60 mJ/p, 80 mJ/p und 100 mJ/p oder einem Nd:YAGLaser und 0.5 W, 1.0 W und 1.5 W bestrahlt. Die Rasterelektronenmikroskopie (REM) wurde verwendet um die Morphologie zu bestimmen, Infrarotspektroskopie (IR) zur Messung der Veränderung in der chemischen Struktur und die eindimensionale paramagnetische Elektronenresonanz-Bildgebung (1-D EPRI) wurde verwendet um die Diffusions-Koeffizienten in den dentalen Wurzelproben abzuschätzen. Ergebnisse: Die Behandlung mit dem Er: YAG-Laser resultierte in der Ausbildung tiefer Krater mit exponiertem Dentin. Die morphologischen Veränderungen der Wurzeloberfläche nach Bestrahlung mit dem Nd: YAG-Laser waren Brüche, Kraterbildung, Aufschmelzen des Wurzelminerals und Bildung wiederverfestigter poröser Globuli. Mit dem Er:YAG-Laser gelang es nicht die Intensität der Amid-peaks I, II oder III zu verändern. Im Gegensatz dazu reduzierte die Behandlung mit dem Nd:YAG-Laser im Vergleich mit der Kontrolle bei der höchsten Leistungseinstellung von 1.5 W die Intensität der Amid-Peaks II und III. In allen mit Er: YAG und Nd:YAG behandelten Wurzelproben waren die Wurzeldiffusionskoeffizienten signifikant erhöht. Schlussfolgerung: Diese Studie demonstrierte, dass der Er:YAG-Laser nur die Morphologie und die Diffusionsprozesse der Wurzeloberfläche beeinflusst, während der Nd: YAG-Laser auch die chemische Struktur der Wurzelproteine verändert. Résumé Morphologie, structure chimique et processus de diffusion de surfaces radiculaires après irradiation au lasers Er:YAG et Nd:YAG But: Le but de cette étude in vitro était d'évaluer les effets des lasers Er:YAG et Nd:YAG sur la morphologie, la structure chimique et les processus de diffusion des surfaces radiculaires. Matériaux et méthodes: 60 échantillons de racines furent irradiés pendant 1 min chacun par 60 mJ/p, 80 mJ/p et 100 mJ/p avec le laser Er:YAG ou par 0.5 W, 1.0 W et 1.5 W avec le laser Nd:YAG. La microscopie électronique à balayage (SEM) a été utilisée pour déterminer la morphologie, la spectroscopie infra rouge pour mettre en évidence les altérations de la structure chimique et l'imagerie en une dimension par résonnance magnétique électronique (1-DEPRI) fut utilisée pour estimer les coefficients de diffusion dans les échantillons de racines dentaires. Résultats: Le traitement au laser Er:YAG entrainait la formation de cratères profonds avec de la detine exposée. Les altérations morphologiques de la surface radiculaire après irradiation au laser Nd:YAG prenaient la forme de félures, de cratères, fusion du minéral radiculaire et formation de globules poreux resolidifiés. Le laser Er:YAG n'arrivait pas à altérer l'intensité des pics Amide I, II our III. Au contraire, le traitement au laser Nd:YAG, en utilisant la plus haute puissance de 1.5 W, réduisait l'intensité des pics Amide II et III, par rapport au contrôle. Les coefficients de diffusion étaient significativement augmentés pour toutes les racines traitées par les lasers Er:YAG et Nd:YAG. Conclusions: Cette étude démontre que le laser Er:YAG a une influence sur seulement la morphologie et les processus de diffusion des surfaces radiculaires alors que le laser Nd:YAG modifie également la structure chinique des protéines radiculaires. [source] | ||||||||||||||||||||||||||||||||||