The aim of this in vitro study was to analyze the influence of different power densities of low-intensity laser therapy (LILT) on the biomodulation of human gingival fibroblasts. The cells were cultured in nutritional deficit. Laser irradiation was carried out with a GaAlAs diode laser (lambda-660 nm, 2 J/cm2). The irradiation was done twice with 12-h interval using the punctual technique, at continuous mode and in contact. The experimental groups were: I, control, nonirradiated; II, power of 10 mW and intensity approximately or equal to 142.85 mW/cm2; III, 29 mW and 428.57 mW/cm2. Growth curves were obtained by using the trypan blue dye exclusion assay. The cell growth of the irradiated groups was significantly higher than control group (P

Rhabdomyomatous hamartoma is a rare disease that occurs predominantly in the skin. This paper describes a congenital lesion in a 17-year-old male, who came to our clinic presenting a circumscribed swelling involving the oral mucosa and vermillion border of the upper lip, purplish in color, and blanching under pressure. The patient reported that he had had lesion since his birth. A clinical diagnosis was of congenital haemangioma, and the patient was treated by photocoagulation using diode laser. When the lesion became smaller, by having its blood content reduced, the upper portion of the lesion was sliced off with CO2 laser and the tissue was sent for microscopic analysis. Histopathological examination showed an oral mucosa fragment with proliferation of striated muscle bundles admixed with small blood vessels, collagen, and nerve fibres. A supplementary analysis with immunohistochemistry demonstrated positivity for desmin, HHF35, smooth muscle actin, S-100, and CD34. Based on these findings, the lesion was diagnosed as rhabdomyomatous hamartoma. The aesthetic result has been very satisfactory after a 14-month followup.

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Photocoagulation with high-intensity diode laser is an effective, bloodless procedure for the treatment of VL.

It was concluded that low-level laser therapy (LLLT) of the thyroid gland may affect the level of thyroidal hormones.

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The aim of this study was to compare the concentration of mast cells (MCs) in the healing process of incisions. Thirty rats were submitted to six linear incisions each, performed in the dorsal skin by carbon dioxide (CO(2)) and diode lasers, electrocautery and conventional scalpel. The animals were euthanized at intervals of 0 h, 24 h, 48 h, 72 h, 7 days and 14 days after the incisions had been made. Histological sections were obtained and stained with toluidine blue for identification of MCs, which were manually counted by conventional microscopy in 20 microscopic fields in the border of the incision, near the granulation tissue, or in the area of new collagen formation, depending on intervals. The concentration of MCs was significantly higher in the wounds made by scalpel than in those made by other techniques at 48 h and 72 h. After 72 h the number of MCs was also significantly higher after electrocautery than after incisions made by 4 W CO(2) laser. On days 7 and 14, there was no significant difference in the MC count among the different types of incisions. In summary, the MC concentration varied after different surgical incisions at early phases of wound healing. At the end of the healing process, however, there were similar MC concentrations around the incisions, suggesting that, in standard incisions in the surgical techniques studied, the wound healing process ultimately occurred in a similar pattern.

SUMMARY:In this work, we studied the effects of CO 2 , Nd:YAG and diode lasers on the enamel and dentin of deciduous human teeth. After the irradiations, the samples were duly prepared and set up on metallic bases, covered with gold and examined in the scanning electron microscope. The results showed that the irradiation with the CO 2 mode locked laser with 1.0 W power caused melting and irregularities with small cavities on the surface of the enamel. The irradiated area on the dentin surface appeared circular and well delimited, containing blocks of dentin and cracks. By using the pulsed Nd:YAG laser with 1.0 W mean power and 10 Hz frequency, the enamel surface presented granules of molten enamel, with a typical melting look. The irradiated dentin surface presented a cavity with a margin elevated with granules and holes, and its bottom presented dentinary tubules with globules of melted dentin. Irradiation with the mode locked of diode laser with 1.0 W mean power, showed the formation of a melted and evenly resolidified enamel surface, and the dentin surface presented a block of melted dentin with adjacent regions of normal dentin, evidently with a relatively smooth surface.