Search results for "electron"
showing 10 items of 24810 documents
Suture needles in Oral Surgery: Alterations depending on the type and number of sutures
2011
This study examined whether the number and type of sutures used in oral surgery influence two ad hoc variables (incision plane and displaced area), which are two variables related to whether the suture needle is suitable for the task. Seventy-five TB-15 needles were studied, which were used to suture between zero and three mucosa and/subperiosteal sutures, producing 15 groups with 5 needles in each one. The incision plane and displaced area were measured for each group, which are two variables related to how the needle has worn and altered. Statistical treatment was conducted using the Kruskal-Wallis H test to compare multiple values and the Mann-Whitney U test to compare pairs. A multi-sta…
Diffuse reflectance and fluorescence multispectral imaging system for assessment of skin
2014
The diffuse reflectance multispectral imaging technique has been used for distant mapping of in vivo skin chromophores (hemoglobin and melanin). The fluorescence multispectral imaging is not so common for skin applications due to complicity of data acquisition and processing, but could provide additional information about skin fluorophores. Both techniques are compatible, and could be combined into a multimodal solution. The multispectral imaging system Nuance based on liquid crystal tunable filters was adapted for diffuse reflectance and fluorescence spectral imaging of in vivo skin. Uniform illumination was achieved by LED ring light. Combination of four LEDs (warm white, 770 nm, 830 nm a…
Water detection in skin by dual-band photodiodes
2013
Purpose of this study was to develop a simple model for possibilities to detect water in skin by diffuse reflectance spectra. The model is based on comparison of diffuse reflectance spectra when illuminating water sample with LEDs of different wavelengths (1200 nm, and 1450 nm). The illumination LEDs were chosen due to water absorption differences in near-infrared spectral range. For detection, dual-band photodiode DSD2 by Thorlabs was used. Due to differences of water absorption at different wavelengths in the near-infrared spectral region, this correlation could be used for mapping of water content in skin or, in other words, determine relative moisture level in skin. Simple experimental …
Surface Topographies of Glaucoma Drainage Devices and Their Influence on Human Tenon Fibroblast Adhesion
2010
PURPOSE. This study was performed to investigate the surface topography of different glaucoma drainage devices and to determine the effects of surface roughness on cell adhesion of cultured human tenon fibroblasts.METHODS. The surface topography of four widely used devices (Ahmed FP7 and Ahmed S-2; New World Medical, Inc., Rancho Cucamonga, CA; Baerveldt BG101-350; Advanced Medical Optics, Irvine, CA; and Molteno S1; Molteno Ophthalmic Ltd., Dunedin, New Zealand) was investigated by scanning electron microscopy, and roughness was quantified by white-light confocal microscopy. Cells were grown for 72 hours on the surfaces of implants affixed to standard culture dishes. The cells were labeled…
Bond strength of cemented fiber posts to teeth with simulated internal root resorption
2020
Made available in DSpace on 2021-06-25T10:58:34Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-03-01 Background: Teeth with internal root resorption (IRR) have guarded prognosis, considering that IRR defect could influence on the post bond strength. The aim of this study was to evaluate the bond strength and the bond interface between different glass fiber-reinforced posts (FRP) after cementation in teeth with simulated internal root resorption (IRR). Material and Methods: Forty-five (45) human premolar roots with simulated IRR were embedded in acrylic resin blocks and cross-sectioned into two segments, enabling them to be re-approximated by screws. Intracanal medication was inserte…
The Effect of surface topographical changes of two different surface treatments rotary instrument
2018
Background One of the major innovations in endodontics has been the introduction of nickel-titanium (NiTi) alloy. This study evaluated the surface topographical changes of two different surface treatments rotary instrument after instrumentation and sterilization. Material and Methods 240 Extracted teeth were included in this study. 90 new AlphaKite and Revo-S NiTi rotary instruments were selected and divided into two groups (Group A 45 AlphaKite and group B 45 Revo-S). Each group were divided into three subgroups: (A1, B1) n=5 files were used as a control, (A2,B2) n=20 files were used to prepare three root canals using endodontic rotary motor then sterilized by autoclave for one cycle under…
Determination of chromophore distribution in skin by spectral imaging
2012
Possibilities to determine chromophore distribution in skin by spectral imaging were explored. Simple RGB sensor devices were used for image acquisition. Totally 200 images of 40 different bruises of 20 people were obtained in order to map chromophores bilirubin and haemoglobin. Possibilities to detect water in vitro and in vivo were estimated by using silicon photodetectors and narrow band LEDs. The results show that it is possible to obtain bilirubin and haemoglobin distribution maps and observe changes of chromophore parameter values over time by using a simple RGB imaging device. Water in vitro was detected by using differences in absorption at 450 nm and 950 nm, and 650 nm and 950 nm.
Efficacy of NaOCl/H2O2irrigation and GaAlAs laser in decontamination of root canals in vitro
2003
Background and Objectives To investigate the bactericidal effect of an 809 nm semiconductor laser alone, and in combination with NaOCl/H2O2 irrigation in root canals in vitro. Study Design/Materials and Methods A total of 72 human single-rooted teeth extracted for periodontal reasons were included. The crowns were removed, the roots shortened to a length of 12 mm, and the canals enlarged up to an apical size of #50 file. The specimens were autoclaved and incubated with a suspension of Streptococcus sanguinis (ATCC 10556). Laser irradiation was performed on a PC-controlled XY translation stage. A 200 micron optic fiber was used. Twelve specimens were irradiated at a power output of 1.5, 3.0,…
Application principles of excimer lasers in ophthalmology
2010
Abstract Excimer lasers (193 nm) can be used for photoablation of the human cornea due to their specific physical characteristics. This laser is applied in corneal refractive surgery for the targeted removal of corneal tissue for the purpose of correcting refractive errors. This article provides a short overview of the scientific development of excimer lasers for use in ophthalmic surgery and of the range of applications of these tools.
Skin autofluorescence photo-bleaching and photo-memory
2011
Photo-bleaching of in-vivo skin autofluorescence intensity under continuous low power laser irradiation has been studied. Temporal behavior of single-spot fluorescence and spectral fluorescent images have been studied at continuous 405 nm, 473 nm and 532 nm laser excitation and/or pre-irradiation, with power densities well below the laser-skin safety limits. Skin autofluorescence photo-memory effects (laser signatures) have been observed and analyzed, as well.