Effect of GaAIAs low-level laser therapy on the healing of human palate mucosa after connective tissue graft harvesting: randomized clinical trial

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Analysis of experimental tendinitis in rats treated with laser and platelet-rich plasma therapies by Raman spectroscopy and histometry

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Efeito dos lasers de Nd:YAG e de Er:YAG na adaptação das obturações de canais radiculares: análise do selamento marginal apical

Pós-graduação em Odontologia Restauradora - ICT

Validation of a stability-indicating HPLC method with diode array detection for the determination of beclomethasone dipropionate in aqueous suspension for nebulizer

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Efeitos de lasers de alta potência na superfície de cerâmicas vítreas de dissilicato de lítio e sua resistência de união à dentina humana

Pós-graduação em Odontologia Restauradora - ICT

Efeitos de lasers de alta potência na superfície de cerâmicas vítreas de dissilicato de lítio e sua resistência de união à dentina humana

Pós-graduação em Odontologia Restauradora - ICT

Polymer Light Emitting Diode Using PFT-Poly(9,9 `-n-dihexil-2,7-fluorenodiilvinylene-alt-2,5thiophene)

The development of new electroluminescence polymers for specific colour tuning in Polymer Light Emitting Devices (PLEDs) is currently one of the most important fields for organic electronics. This work reports a synthesis of a new electroluminescent polymer and the concomitant test as PLED emissive layer. The polymer, synthesised from fluorene, is poly(9,9`-n-dihexil-2,7-fluorenodiilvinylene-alt-2,5thiophene) or PFT The luminescence shows large bands with maxima around 480 nm in absorption and 560 nm in emission. The device was made in a three layer structure, with PEDOT:PSS as hole transport layer, PFT as emissive layer and butyl-PBD as electron transport layer. The electroluminescence spectrum shows a strong band peaked at 540 nm. For an applied voltage of 12 Volt, the brightness at normal angle of viewing is near 10 cd/m(2) and the luminous efficiency is of 0.01 lm/W. A discussion about carrier transport and the electroluminescence properties is made.

Effects of Er:YAG and Er,Cr:YSGG lasers on dentine hypersensitivity. Short-term clinical evaluation

Dentine hypersensitivity (DH) is a painful condition and is a clinical challenge due to the different treatment strategies available. High-intensity lasers have been studied as a possible option. The aim of this randomized, controlled, double-blind clinical study was to evaluate the effects of Er:YAG and Er,Cr:YSGG lasers on DH. The study group comprised 28 subjects who met the inclusion criteria. A visual analogue scale was used to quantify sensitivity before treatment as baseline, immediately before and immediately after treatment, and 1 week and 1 month after treatment. Teeth were assigned to four groups: group 1 control (no treatment), group 2 Er:YAG laser treatment (2 Hz/32.4 mJ/5.9 J/cm(2)), group 3 Er,Cr:YSGG laser treatment (0.25 W/4.4 J/cm(2)), and group 4 Er,Cr:YSGG laser treatment (0.50 W/ 8.9 J/cm(2)). Data were collected and submitted to statistical analysis for both evaporative (air) and mechanical (probe) stimulation. For both the air and probe stimulation no differences were observed between the pretreatment sensitivities. With the evaporative stimulus, the pain level immediately after treatment was reduced; however, after this the values remained stable. Irradiation with the Er:YAG laser was associated with the lowest level of pain. With the mechanical stimulus, group 4 showed the most pronounced decrease in pain immediately after treatment; however, by the end of the study, pain levels had increased. Groups 1, 2 and 3 showed a reduction in pain that was significantly different from that in group 4 after the 4 weeks of clinical follow up. Based on the results and within the limits of this study, it can be concluded that none of the laser treatments studied was capable of completely eliminating pain, but the Er:YAG and Er,Cr:YSGG lasers are suitable for the treatment of DH.

Skin Penetration Time-Profiles for Continuous 810nm and Superpulsed 904nm Lasers in a Rat Model

Objective: The purpose of this study was to investigate the rat skin penetration abilities of two commercially available low-level laser therapy (LLLT) devices during 150 sec of irradiation. Background data: Effective LLLT irradiation typically lasts from 20 sec up to a few minutes, but the LLLT time-profiles for skin penetration of light energy have not yet been investigated. Materials and methods: Sixty-two skin flaps overlaying rat's gastrocnemius muscles were harvested and immediately irradiated with LLLT devices. Irradiation was performed either with a 810 nm, 200mW continuous wave laser, or with a 904 nm, 60mW superpulsed laser, and the amount of penetrating light energy was measured by an optical power meter and registered at seven time points (range, 1-150 sec). Results: With the continuous wave 810nm laser probe in skin contact, the amount of penetrating light energy was stable at similar to 20% (SEM +/- 0.6) of the initial optical output during 150 sec irradiation. However, irradiation with the superpulsed 904 nm, 60mW laser showed a linear increase in penetrating energy from 38% (SEM +/- 1.4) to 58% (SEM +/- 3.5) during 150 sec of exposure. The skin penetration abilities were significantly different (p < 0.01) between the two lasers at all measured time points. Conclusions: LLLT irradiation through rat skin leaves sufficient subdermal light energy to influence pathological processes and tissue repair. The finding that superpulsed 904nm LLLT light energy penetrates 2-3 easier through the rat skin barrier than 810nm continuous wave LLLT, corresponds well with results of LLLT dose analyses in systematic reviews of LLLT in musculoskeletal disorders. This may explain why the differentiation between these laser types has been needed in the clinical dosage recommendations of World Association for Laser Therapy.

Argon and Nd:YAG Lasers for Caries Prevention in Enamel

Objective: The aim of this study was to investigate the effect of Nd:YAG and argon laser irradiations on enamel demineralization after two different models to induce artificial caries. Background data: It is believed that the use of the high-intensity laser on the dental structure can lead to a more acid-resistant surface. Materials and methods: Twenty-one extracted human third molars were sectioned into tooth quarters. The quarters were distributed in three groups: Group I (control), untreated; Group II, Nd:YAG laser (60 mJ, 15 pps, 47.77 J/cm(2), 30 sec); and Group III, argon laser (250mW, 12 J/cm(2), 48 sec). Tooth quarters from each group were subjected to two different demineralization models: cycle 1, a 14 day demineralization (pH 4.5; 6 h) and remineralization (pH 7.0; 18 h) solutions, 37 degrees C and cycle 2, 48 h in demineralization solution (pH 4.5). Samples were prepared in slices (60-100 mu m thick) to be evaluated under polarized light microscopy. Demineralization areas were measured (mm(2)) (n = 11). Data were analyzed by ANOVA and Tukey's test (p < 0.05). Results: Means followed by different letters are significantly different: 0.25 A (control, cycle 48 h); 0.18 AB (control, cycle 14 days); 0.17 AB (Nd:YAG, cycle 14 days); 0.14 BC (argon, cycle 48 h); 0.09 BC (Nd:YAG, cycle 48 h), and 0.06 C (argon, cycle 14 days). Conclusions: The argon laser was more effective for caries preventive treatment than Nd: YAG laser, showing a smaller demineralization area in enamel.

Influence of prior 810-nm-diode intracanal laser irradiation on hydrophilic resin-based sealer obturation

Dentin wall structural changes caused by 810-nm-diode laser irradiation can influence the sealing ability of endodontic sealers. The objective of this study was to evaluate the apical leakage of AH Plus and RealSeal resin-based sealers with and without prior diode laser irradiation. Fifty-two single-rooted mandibular premolars were prepared and divided into 4 groups, according to the endodontic sealer used and the use or non-use of laser irradiation. The protocol for laser irradiation was 2.5W, continuous wave in scanning mode, with 4 exposures per tooth. After sample preparation, apical leakage of 50% ammoniacal silver nitrate impregnation was analyzed. When the teeth were not exposed to irradiation, the Real Seal sealer achieved the highest scores, showing the least leakage, with significant differences at the 5% level (Kruskal-Wallis test, p = 0.0004), compared with AH Plus. When the teeth were exposed to the 810-nm-diode laser irradiation, the sealing ability of AH Plus sealer was improved (p = 0282). In the Real Seal groups, the intracanal laser irradiation did not interfere with the leakage index, showing similar results in the GRS and GRSd groups (p = 0.1009).

Temperature changes on the root surfaces of mandibular incisors after an 810-nm high-intensity intracanal diode laser irradiation

Temperature changes caused by laser irradiation can promote damage to the surrounding dental tissues. In this study, we evaluated the temperature changes of recently extracted human mandibular incisors during intracanal irradiation with an 810-nm diode laser at different settings. Fifty mandibular incisors were enlarged up to an apical size of ISO No. 40 file. After the final rinse with 17% ethylenediaminetetraacetic acid, 0.2% lauryl sodium sulfate biologic detergent, and sterile water, samples were irradiated with circular movements from apex to crown through five different settings of output power (1.5, 2.0, 2.5, 3.0, and 3.5 W) in continuous mode. The temperature changes were measured on both sides of the apical and middle root thirds using two thermopar devices. A temperature increase of 7 degrees C was considered acceptable as a safe threshold when applying the diode laser. Results: The results showed that only 3.5-W output power increased the outer surface temperature above the critical value. Conclusion: The recommended output power can be stipulated as equal to or less than 3 W to avoid overheating during diode laser irradiation on thin dentin walls. (c) 2012 Society of Photo-Optical Instrumentation Engineers (SPIE). [DOI: 10.1117/1.JBO.17.1.015006]

Microhardness of Radicular Dentin Treated with 980-nm Diode Laser and Different Irrigant Solutions

Objective: The aim of this study was to evaluate the microhardness of radicular dentin after treatment with 980-nm diode laser and different irrigant solutions. Background data: There are few reports of the consequences of diode laser irradiation emitted at 980 nm on the mechanical properties of dentin. Methods: Seventy-two single canal, human canines with complete root formation were randomly distributed among three groups (n = 24), according to the irrigant solution used in the biomechanical preparation: distilled water; 1% NaOCl; and, 1% NaOCl + 17% EDTA. These groups subsequently were divided into three subgroups (n = 8), according to the diode laser parameter: no irradiation (control); 1.5W/100 Hz; and 3.0 W/100 Hz. Laser was applied with helicoidal movements for 20 sec. Roots were sectioned in slices and the fragment corresponding to the middle third was submitted to the microhardness test (KHN) at depths of 30, 90, 150, and 300 mu m. Results: ANOVA and Tukey tests showed that the microhardness of the groups irradiated with 1.5 W/100 Hz (49.7 +/- 11.2) and 3.0W/100 Hz (50.6 +/- 11.9) were statistically similar to each other (p > 0.05) and different (p < 0.05) from the non-irradiated group (45.0 +/- 9.7). Higher microhardness values were obtained at 150 mu m (49.2 +/- 11.0) and 300 mu m (52.3 +/- 11.3) which were similar among themselves and different (p < 0.05) only at the depth of 30 mu m (44.4 +/- 10.5). No differences were found among the irrigant solutions (p > 0.05). Conclusions: The microhardness of the radicular dentin increased after irradiation with 980-nm diode laser.

Effects of the combination of low-level laser irradiation and recombinant human bone morphogenetic protein-2 in bone repair

Low-level laser irradiation (LLLI) and recombinant human bone morphogenetic protein type 2 (rhBMP-2) have been used to stimulate bone formation. LLLI stimulates proliferation of osteoblast precursor cells and cell differentiation and rhBMP-2 recruits osteoprogenitor cells to the bone healing area. This in vivo study evaluated the effects of LLLI and rhBMP-2 on the bone healing process in rats. Critical bone defects were created in the parietal bone in 42 animals, and the animals were divided into six treatment groups: (1) laser, (2) 7 mu g of rhBMP-2, (3) laser and 7 mu g of rhBMP-2, (4) 7 mu g of rhBMP-2/monoolein gel, (5) laser and 7 mu g rhBMP-2/monoolein gel, and (6) critical bone defect controls. A gallium-aluminum-arsenide diode laser was used (wavelength 780 nm, output power 60 mW, beam area 0.04 cm(2), irradiation time 80 s, energy density 120 J/cm(2), irradiance 1.5 W/cm(2)). After 15 days, the calvarial tissues were removed for histomorphometric analysis. Group 3 defects showed higher amounts of newly formed bone (37.89%) than the defects of all the other groups (P < 0.05). The amounts of new bone in defects of groups 1 and 4 were not significantly different from each other (24.00% and 24.75%, respectively), but were significantly different from the amounts in the other groups (P < 0.05). The amounts of new bone in the defects of groups 2 and 5 were not significantly different from each other (31.42% and 31.96%, respectively), but were significantly different from the amounts in the other groups (P < 0.05). Group 6 defects had 14.10% new bone formation, and this was significantly different from the amounts in the other groups (P < 0.05). It can be concluded that LLLI administered during surgery effectively accelerated healing of critical bone defects filled with pure rhBMP-2, achieving a better result than LLLI alone or the use of rhBMP-2 alone.

Low-level laser therapy (LLLT) in human progressive-intensity running: effects on exercise performance, skeletal muscle status, and oxidative stress

The aim of this work was to evaluate the effects of low-level laser therapy (LLLT) on exercise performance, oxidative stress, and muscle status in humans. A randomized double-blind placebo-controlled crossover trial was performed with 22 untrained male volunteers. LLLT (810 nm, 200 mW, 30 J in each site, 30 s of irradiation in each site) using a multi-diode cluster (with five spots - 6 J from each spot) at 12 sites of each lower limb (six in quadriceps, four in hamstrings, and two in gastrocnemius) was performed 5 min before a standardized progressive-intensity running protocol on a motor-drive treadmill until exhaustion. We analyzed exercise performance (VO(2 max), time to exhaustion, aerobic threshold and anaerobic threshold), levels of oxidative damage to lipids and proteins, the activities of the antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT), and the markers of muscle damage creatine kinase (CK) and lactate dehydrogenase (LDH). Compared to placebo, active LLLT significantly increased exercise performance (VO(2 max) p = 0.01; time to exhaustion, p = 0.04) without changing the aerobic and anaerobic thresholds. LLLT also decreased post-exercise lipid (p = 0.0001) and protein (p = 0.0230) damages, as well as the activities of SOD (p = 0.0034), CK (p = 0.0001) and LDH (p = 0.0001) enzymes. LLLT application was not able to modulate CAT activity. The use of LLLT before progressive-intensity running exercise increases exercise performance, decreases exercise-induced oxidative stress and muscle damage, suggesting that the modulation of the redox system by LLLT could be related to the delay in skeletal muscle fatigue observed after the use of LLLT.