83 resultados para Gallium.


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Pós-graduação em Odontologia - FOAR

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Pós-graduação em Biopatologia Bucal - ICT

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The aim of this study was to evaluate the influence of chlorhexidine and Er, Cr:YSGG laser irradiation on the bond strength and external adaptation in mixed healthy and caries-affected class V cavities before and after thermal cycling. Thirty-six cavity preparations were made in mixed class V buccal human molars, half of them being artificially caries-induced. Any remaining affected dentin was removed from the cavity with a round burr at low speed. The teeth were divided into six groups, according to cleaning agent for both healthy and caries-induced dentin: no treatment, chlorhexidine and erbium, chromium-doped: yttrium, scandium, gallium, garnet (Er,Cr:YSGG) laser irradiation. A Filtek P90 (3M ESPE, St Paul, MN, USA) silorane adhesive restorative system was used. The specimens were subjected to 5000 thermal cycles (5-55 degrees C 60 min). Epoxy replicas were obtained to characterize the external adaptation under scanning electron microscopy. The average percentages of non-continuous margins were 5.41% and 6.49% in enamel dentin before thermal cycling and 25% and 33.7% after thermal cycling, respectively. The caries-affected and laser irradiated cavities showed higher non-continuous margins. Thermal cycling was able to raise the percentage of non-continuous margin for all groups. Chlorhexidine did not affect the marginal adaptation results, and the Er,Cr:YSGG laser irradiation showed significantly worse results compared with the control group.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Candida albicans is classified into different serotypes according to cell wall mannan composition and cell surface hydrophobicity. Since the effectiveness of photodynamic therapy (PDT) depends on the cell wall structure of microorganisms, the objective of this study was to compare the sensitivity of in vitro biofilms of C. albicans serotypes A and B to antimicrobial PDT. Reference strains of C. albicans serotype A (ATCC 36801) and serotype B (ATCC 36802) were used for the assays. A gallium-aluminum-arsenide laser (660 nm) was used as the light source and methylene blue (300 mu M) as the photosensitizer. After biofilm formation on the bottom of a 96-well microplate for 48 h, each Candida strain was submitted to assays: PDT consisting of laser and photosensitizer application (L + P+), laser application alone (L + P-), photosensitizer application alone (L-P+), and application of saline as control (L-P-). After treatment, biofilm cells were scraped off and transferred to tubes containing PBS. The content of the tubes was homogenized, diluted, and seeded onto Sabouraud agar plates to determine the number of colony-forming units (CFU/mL). The results were compared by analysis of variance and Tukey test (p < 0.05). The two strains studied were sensitive to PDT (L + P+), with a log reduction of 0.49 for serotype A and of 2.34 for serotype B. Laser application alone only reduced serotype B cells (0.53 log), and the use of the photosensitizer alone had no effect on the strains tested. It can be concluded that in vitro biofilms of C. albicans serotype B were more sensitive to PDT.

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The aim of this study was to evaluate the effects of different power parameters of an Erbium, Cromium: Yttrium, Scandium, Gallium, Garnet laser (Er,Cr:YSGG laser) on the morphology, attachment of blood components (ABC), roughness, and wear on irradiated root surfaces. Sixty-five incisive bovine teeth were used in this study, 35 of which were used for the analysis of root surface morphology and ABC. The remaining 30 teeth were used for roughness and root wear analysis. The samples were randomly allocated into seven groups: G1: Er,Cr:YSGG laser, 0.5 W; G2: Er,Cr:YSGG laser, 1.0 W; G3: Er,Cr:YSGG laser, 1.5 W; G4: Er,Cr:YSGG laser, 2.0 W; G5: Er,Cr:YSGG laser, 2.5 W; G6: Er,Cr:YSGG laser, 3.0 W; G7: scaling and root planning (SRP) with manual curettes. The root surfaces irradiated by Er,Cr:YSGG at 1.0 W and scaling with manual curettes presented the highest degrees of ABC. The samples irradiated by the Er,Cr:YSGG laser were rougher than the samples treated by the manual curette, and increasing the laser power parameters caused more root wear and greater roughness on the root surface. The Er,Cr:YSGG laser is safe to use for periodontal treatment, but it is not appropriate to use irradiation greater than 1.0 W for this purpose. Microsc. Res. Tech. 78:529–535, 2015. © 2015 Wiley Periodicals, Inc.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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The aim of this study was to evaluate the effects of the use of a high-power gallium-aluminum-arsenide diode laser (GaAlAs; 808 nm, 1 W, 20 s, 20 Hz, 10 J) alone or as adjunctive therapy to scaling and root planing in the treatment of induced periodontitis in rats. Periodontitis was induced by placing a ligature around the mandibular first molar of 60 rats. After 7 days, the ligature was removed and the animals were divided into four groups as follows: C (control), no periodontal treatment; SRP, scaling and root planing (SRP); DL, diode laser (DL) irradiation treatment; and SRP/DL, both SRP and DL irradiation treatment. Five animals from each group were euthanized at 7, 15, and 30 days posttreatment. The effectiveness of the treatments was evaluated in the furcation area using histopathological analysis, histometric analysis of alveolar bone loss (ABL), and immunohistochemical detection of tartrate-resistant acid phosphatase (TRAP), runt-related transcription factor 2 (RUNX2), and osteocalcin (OCN). DL, alone or in combination with adjunctive therapy to SRP in the treatment of experimental periodontitis, resulted in a decreased local inflammatory response. At 7-days posttreatment, the DL and SRP/DL groups had fewer TRAP-positive cells and more RUNX2-positive cells. There was greater OCN immunolabeling in the DL group than in the C and SRP groups at 15 days. There was less ABL in the DL and SRP/DL groups at 15 and 30 days. In conclusion, DL was effective in the treatment of ligature-induced periodontitis in rats, both when used alone and when used as adjunctive therapy to SRP.