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Search Results: 1 - 10 of 7300 matches for " Nd: Yag laser "
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Microstructural Morphological Changes in Laser Irradiated Platinum  [PDF]
A. Latif, M. Khaleeq-ur-Rahman, K. A. Bhatti, M. S. Rafique, Asma Hayat
Journal of Modern Physics (JMP) , 2011, DOI: 10.4236/jmp.2011.28104
Abstract: The micro structural morphological investigations of the laser exposed samples of Platinum are presented. Q-Switched Nd: YAG laser (1064 nm, 1.1 MW, 9 - 14 ns) represented by Gaussian profile, power density 3 × 1015 Watt/m2 and focal spot size 12 μm is used to irradiate the targets (4 N, 1 × 1 × 0.3 cm3). Surface modifications are observed and examined for optimized 50 pulses in air (1 atm) as well as under vacuum (10-3 torr) by analyzing SEM micrographs. Ripples, cones, crater and hillocks formation, splashing, sputtering, solidification and redeposition are observed as main modifications at the irradiated surface. It is explored that material is ejected with explosive expel. Motic digital microscope is used for the measurements of ablated micron sized droplets. The average distance between the adjacent cones is larger near the crater region. Topographical changes are characterized applying Atomic Force Microscopy. RMS surface roughness, hillocks and crater sizes on the irradiated surfaces are also calculated. The structural analysis is mainly focused on measurements of grain sizes, diffracted X-Rays intensity and interplanar distance. The results thus obtained determine that IR radiations are unable to change interplanar distance of the target where as changes in diffracted x-rays intensity and grain sizes for irradiated platinum are noticed.
An evaluation on shear strength of composite resin bonded to primary teeth dentin after Nd: YAG laser radiation
Kowsari A,Seraj B,? PasdarN
Journal of Dental Medicine , 2002,
Abstract: Due to the differences in the composite and morphology of dentin in primary and permanent teeth, it is necessary to make improvements in bonding techniques to promote the strength of composite resins bonded to the dentinal surface, in primary teeth. The use of lower radiation, to make structural and chemical changes in dentinal surfaces has been investigated. This research was conducted to evaluate the shear strength of the composite bonded to primary teeth dentin after Nd: YAG laser radiation and acid etching for conditioning. Peripheral dentin of the buccal and lingua! surfaces of 60 extracted posterior primary teeth were exposed and polished with 600 grit with Sic paper. The teeth were divided randomly in 3 groups of 20 teeth. In group 1 etching gel, primer and adhesive of scotch bond multipurpose system (SMP), in group 2 laser at 1.6 w and 80 mj/pulse, and in group 3 laser at 2 s and 700 mj/pulse were used. Moreover, in groups 2 and 3, after laser radiation, acid etching, primer and adhesive of SMP system were applied. After necessary laboratory tests, the mean shear bond strength in MPa were 20.99±5.3 (group 1), 23.82±6.31 (group 2) and 26.58±5.59 (group 3). ANOVA, scheffe, tukey statistical tests showed that the bond strengths of group 3 were statistically higher than group 1. The frequency of dentin cohesive failures were significantly higher in groups 2 and 3, compared to group 1 that indicates a higher bond strength in these groups. Scanning electron mirographs of laser radiated surfaces, show a porous and rough surface morphology that enhances the mechanical bond of the composite.
Aplicaciones del láser Nd:YAG en Odontología
Zavaleta-de la Huerta,Débora; Espa?a-Tost,Antonio Jesús; Berini-Aytés,Leonardo; Gay-Escoda,Cosme;
RCOE , 2004, DOI: 10.4321/S1138-123X2004000500005
Abstract: the nd:yag laser is composed of a garnet of yttrium and aluminium, doped with neodymium. its emission wavelength is 1064 nm, in the near infrared spectrum. unlike other lasers, the nd:yag laser energy can be transmitted through optic fibre, which facilitates its use in anatomic oral and dental areas of difficult access. this fact, together with the powerful bacteriostatic effect of this wavelength, turn this laser into a useful tool for endodontic and periodontal therapies, improving the results of conventional techniques. it is also used in certain procedures in the field of oral surgery, basically for the removal of soft tissue pathologies.
The Q-Switched Nd: YAG Laser in Tattoo Removal and the Effect of Lymphatic Elimination: An Experimental Study in Rabbits  [PDF]
S. Irkoren, C. Demirdover, B. Z. Akad, M. Gorgu
Surgical Science (SS) , 2011, DOI: 10.4236/ss.2011.25058
Abstract: Background: Previously described methods for removal of tattoos are chemical, mechanical, surgical, termal and laser assited methods. Invention of the Q-switch mode, advanced the laser method, to be one of the most effective methods of tattoo removal. Objective: Comparing the tattoo removal and rate of lymphatic elimination of 3 different wavelengths of Q-switched Nd-YAG laser (532nm, 1064nm, combination 532 + 1064). Methods: In this study we examined lymphatic elimination and the effect of 532 nm, 1064 nm, and the combination (532 + 1064 nm) wavelength of laser pulse for the possible lymphatic cleansing mechanism of black pigmented tattoos. This study was performed on 18 New-Zealand rabbits, black pigmented tattoos were engraved on the back and the four extremities of the animals. 532 nm wavelength of Q switched Nd: YAG laser beam was applied on the left upper and bilateral lower extremities of the rabbits. During this period, excisional skin biopsies and lymph node biopsies were performed on days 7, 14 and 21. Results: Day 21 lymph node biopsies revealed mixed type of reactive hyperplasia and intracellular pigments were markedly seen in the laser treatment group and no intracellular tattoo pigment was seen in the control group. Conclusion: The findingd of this study indicate that lymphatic elimination may be one of the significant mechanisms of tattoo removal and the application of different wavelengths of Q-switched Nd-YAG laser do not show statistically significant differences in tattoo removal.
Efficacy of Nd:YAG Laser for the Treatment of Hidradenitis Suppurativa  [PDF]
Neda Nosrati, Lindsey Hunter, Erica Kelly
Journal of Cosmetics, Dermatological Sciences and Applications (JCDSA) , 2012, DOI: 10.4236/jcdsa.2012.22019
Abstract: Hidradenitis suppurativa (HS) is an inflammatory skin disease that involves sebaceous glands and hair follicles of intertriginous areas, including axillary and inguinal regions. It is often chronic, painful, disabling, and can worsen over time. Besides surgically excising affected areas, effective treatments are currently lacking. The long-pulsed neodymium:yttrium-aluminium-garnet (Nd:YAG) laser is a device that has traditionally been used for hair removal, but has recently shown promise in clearing old lesions of HS and preventing new eruptions. In accordance with studies in the current literature, we hypothesize that the Nd:YAG laser will significantly improve subjects with hidradenitis suppurativa compared to standard, uninvasive treatment with topical antibiotics [1,2]. Study aims include: to treat subjects with hidradenitis suppurativa with Nd:YAG laser therapy once monthly for 3 consecutive months, with a one month follow-up; to compare the effectiveness of Nd:YAG treatment on one side of the subject (e.g., right) to treatment with topical antibiotics on the subject’s other side (e.g., left); to assess treatment response using a visual analogue scale; to assess subject satisfaction with treatment using a questionnaire; and to photodocument treatment response at each visit.
Effect of Different Irradiation Times on the Occlusion of Dentinal Tubules When Using a Nd:YAG Laser: An in Vitro SEM Study  [PDF]
Xiaoyu Guo, Jinhua Yu, Roger J. Smales, Huifen Chen, Haiyan Si, Younong Wu
Open Journal of Stomatology (OJST) , 2015, DOI: 10.4236/ojst.2015.53011
Abstract: Objective: To evaluate the effect of different irradiation times on the occlusion of dentinal tubules when using Nd:YAG laser. Background data: Dentin hypersensitivity is a frequent problem that has limited treatment success despite many chemical and physical therapies. Methods: Four coronal dentin disks 2 mm thick were cut with a low-speed diamond saw from four freshly extracted intact first molars. The coronal dentin surface of each disk was divided into four regions, each approximately 2 mm × 3 mm. The dentin surfaces were treated with 27% EDTA then the four regions irradiated separately in a randomized pattern with a Nd:YAG laser (120 mJ, 5 Hz), using irradiation times of 0 s, 20 s, 40 s and 60 s, representing laser energies of 0 J/cm2, 200 J/cm2, 400 J/cm2 and 600 J/cm2, respectively. SEM photomicro-graphs were taken at 1500× and 3000× to calculate the dentinal tubule orifice occlusion rates and to measure the tubule diameters, respectively. Results: For the laser irradiation times of 0 s, 20 s, 40 s and 60 s, the corresponding dentinal tubule occlusion rates were 2.05 (SD 0.29)%, 10.01 (1.71)%, 23.58 (2.51)% and 90.23 (2.24)%, respectively; and the tubule diameters were 4.18 (0.32) μm, 3.46 (0.24) μm, 1.69 (0.32) μm and 0.12 (0.02) μm, respectively. There were significant differences among all groups for both measured variables (p ≤ 0.005). Conclusions: Within the limitations of this in Vitro study, when using a Nd:YAG laser at 120 mJ and 5 Hz, an irradiation time of 60 s achieved the best sealing of the coronal dentinal tubule orifices.
Treatment of hemangiomas in children using a Nd:YAG laser in conjunction with ice cooling of the epidermis: techniques and results
Ioannis Vlachakis, Stefanos Gardikis, Eleni Michailoudi, Georgios Charissis
BMC Pediatrics , 2003, DOI: 10.1186/1471-2431-3-2
Abstract: Between 1993 and 2001, 110 patients aged 3 months to 4 years, with cutaneous hemangiomas were treated with a Nd:YAG laser. The lesion was cooled with ice prior to, during, and after the irradiation. During each session the laser beam passed through the pieces of ice. The laser power was between 35–45 W with a pulse length of 2–10 seconds.After 6 months of follow-up, from the first session of laser treatment, total resolution was obtained in 72 (65.5%) patients. A second or third session followed in 30 out of 38 patients in which, the initial results were good, moderate, or poor. The parents of the remaining eight children refused this second session and these patients excluded from the study Complications were seen in nine (8.8%) patients. One patient had postoperative bleeding which stopped spontaneously, while atrophic scars occurred in six (5.8%) patients, and hypertrophic scars in two (1.9%) patients.Nd:YAG laser irradiation in conjunction with ice protection of the epidermis produces good cosmetic results for the treatment of cutaneous hemangiomas in children, and decreases the number of sessions for treatment of these lesions.A hemangioma is a benign congenital vascular malformation and the most common type of tumor in infancy. It has been reported that 1.1 – 2.6% of newborns suffer from this vascular lesion, and this number increases to 10.1% by 12 months of age [1]. They are usually absent at birth but appear and enlarge during the first 6 months of life, and often continue to grow until 12 months of age. After this proliferative phase, slow involution follows in most cases, with almost complete disappearance by 5–10 years of age [2-4]. However, in 10 – 20% of cases with cutaneous hemangioma, complications appear such as ulceration and bleeding, and the involvement of important functions such as vision, respiration, hearing, or feeding. These complications, along with cosmetic disfigurement, are a clear indication for treatment and should immediately lead to
Análise micromorfológica de esmalte e dentina expostos ao laser de Nd: YAG em regime de picossegundos
Lizarelli, Rosane de Fátima Zanirato;Bagnato, Vanderlei Salvador;
Pesquisa Odontológica Brasileira , 2002, DOI: 10.1590/S1517-74912002000300008
Abstract: the efficiency of the ablation obtained with a picosecond-pulsed laser system minimizes material collateral damage because of the etching and plasma formation mechanism. it prevents the excessive generation of shock waves and promotes a considerable decrease of mechanical side effects. in this study, a nd:yag picosecond-pulsed q-switched and mode-locked laser (antares 76-s, coherent, palo alto, ca) was used. fifteen microcavities were prepared in the enamel, and nine microcavities were prepared in the dentin of three recently extracted human molars. the parameters for irradiating enamel followed a fixed frequency of 100 hz and an average power level of 1.3 w; for dentin, the frequency was fixed in 15 hz, and the average power level varied between 800, 700 and 600 mw. enamel proved more capable to dissipate shock waves than dentin, since cracks originating from microcavities were more frequent in dentin. in conclusion, it seems that in order to keep defined edges, it is important to choose shorter irradiation periods when average power levels are kept high, which results in lower and best-localized total energy delivery.
Análise micromorfológica de esmalte e dentina expostos ao laser de Nd: YAG em regime de picossegundos
Lizarelli Rosane de Fátima Zanirato,Bagnato Vanderlei Salvador
Pesquisa Odontológica Brasileira , 2002,
Abstract: A eficiência da abla o com laser através de um regime de picossegundos minimiza a destrui o do material adjacente devido à forma o de plasma e ataque. Isso previne a gera o excessiva de ondas de choque e promove uma considerável diminui o nos efeitos mecanicos. Nesse estudo foi utilizado um laser de Nd:YAG em picossegundo "Q-switched" e "mode-locked" (Antares 76-s, Coherent, Palo Alto, CA), três molares humanos recém-extraídos e foram realizados 15 microcavidades em esmalte e 9 em dentina. Os parametros para irradiar o esmalte seguiram uma freqüência fixa de 100 Hz e potência média de 1,3 W; enquanto que para a dentina, a freqüência foi fixa em 15 Hz enquanto que a potência média variou em 800, 700 e 600 mW. O esmalte demonstrou ser mais capaz de dissipar as ondas de choque do que a dentina, uma vez que as trincas originadas nas microcavidades foram mais freqüentes em tecido dentinário, diferentemente do esmalte. Em conclus o, parece que para manter os aspectos de defini o de bordas é importante escolher tempos de irradia o mais curtos, quando as potências médias forem mantidas mais altas, ou seja, energia total entregue mais baixa e bem localizada.
Refractory Port Wine Stains (PWS): Long Pulsed Alexandrite Laser as an Option
Hassan Seirafi,Farshad Farnaghi,Amirhooshang Ehsani,Majid Asghari Shiekhi
Journal of Lasers in Medical Sciences , 2012,
Abstract: INTRODUCTION: Port wine stains (PWS) are congenital vascular malformations. Pulsed dye laser (PDL) is the treatment of choice till now, although many lesions do not respond completely. One of possible options is long pulsed alexandrite laser. Some literatures confirmed its efficacy. The aim of the present study is to determine the efficacy of this laser as an option in treating refractory PWS in Iranian patients. METHODS: Patients with refractory PWS lesions that did not respond to at least six PDL sessions were included if they had no history of Isotretinoin consumption in past year, history of keloid or hypertrophic scar formation, active infection in laser site and if they were not pregnant. All patients signed an informed consent. Alexandrite laser with fluencies from 36-40J/Cm2, 12 mm spot size, 3 ms pulse duration and dynamic cooling device tuned to 50/50 ms was used in three successive sessions to treat lesions. All patients photographed before each session and after 8 weeks from the last sessions. Then, pictures were rated by two blinded dermatologist rater to determine degree of response based of visual analog scaling from score 1(below 25% response) to score 4 (more than 75% response). RESULTS: A total of 20 patients comprised of 12 males and 8 females with mean age of 23 years were included. 35% (7 patients) had score of 1, 35% (7 patients) had score of 2, 25% (5 patients) had score of 3 while one patient (5%) reached score 4. No serious side effect was observed. There was no significant relationship with age, gender and size of lesions and response rate. CONCLUSION: It seems that considering a conservative approach, long pulsed alexandrite laser may be an effective option in treating refractory PWS lesions. Although future studies with higher sample size using higher fluences are required to confirm these results.
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