Search results for "Biomedical engineering"

Finite Element Method and Von Mises Investigation on Bone Response to Dynamic Stress with a Novel Conical Dental Implant Connection

2020

The bioengineering and medical and biomedical fields are ever closer, and they manage to obtain surprising results for the development of new devices. The field of simulations and studies in silica has undergone considerable development in recent years, favoring the advancement of medicine. In this manuscript, a study was carried out to evaluate the force distribution on the implant components (In-Kone® Universal) and on the peri-implant tissues subjected to loading. With the finite element analysis and the Von Mises method, it was possible to evaluate this distribution of forces both at 0 degrees (occlusal force) and at 30 degrees; the applied force was 800 N. The obtained results on this …

The influence of platform switching on the biomechanical aspects of the implant-abutment system. A three dimensional finite element study

2011

Objective: To evaluate the biomechanical scenario of platform switching geometric implant-abutment configuration relative to standard configurations by means of finite element analysis.Study Design: A 3D Finite Element Analysis (FEA) was performed on 3 different implant-abutment configurations: a 3.8 mm implant with a matching diameter abutment (Standard Control Design, SCD), a 5.5 mm implant with matching diameter abutment (Wider Control Design, WCD), and a 5.5mm implant with a 3.8 mm abutment (Experimental Design, ED). All the different experimental groups were discretized to over 60000 elements and 100000 nodes, and 130N vertical (axial) and 90N horizontal loads were applied on the coron…

Remote photoplethysmography for assessment of oral mucosa

2019

The present study is devoted to the assessment of oral mucosa perfusion using remote photoplethysmography (rPPG) technique. The alterations of mucosal perfusion were evoked by regional infiltration anesthesia containing adrenaline. Simple rPPG setup comprising white LED light source, video camera and narrowband optical filter (CWL=540nm), are able to detect subtle microcirculation changes in gingiva. Results demonstrate substantial decrease of rPPG waveform amplitude and subsequently perfusion index in affected gingiva region, following administration of anesthetics. The present study emphasizes clinical advantages of remote photoplethysmography and perfusion index mapping as a simple and c…

In vitro analysis of the pH stability of dental bleaching gels during in-office procedures

2021

Background Previous studies have shown that acidic bleaching gels could lead to worse collateral effects during an in-office bleaching procedure, while neutral or basic products leads towards a better experience. Considering this fact, the main purpose of this study was to evaluate the pH behavior of 6 in-office bleaching gels, compared to the information provided by their manufacturers. Material and methods Thirty enamel discs of bovine teeth were prepared, the initial colors of which were measured by a spectrophotometer and then divided into 6 groups. A pH meter was used to measure the pH every 30 seconds until the end of each procedure, when a new color evaluation was then made. The Tuke…

Method and apparatus using selected superparamagnetic labels for rapid quantification of immunochromatographic tests

2009

Mika PA Laitinen1, Jari Salmela2, Leona Gilbert1, Risto Kaivola1, Topi Tikkala2, Christian Oker-Blom1, Jukka Pekola3, Matti Vuento11Department of Biological and Environmental Science; 2Department of Physics, University of Jyväskylä, Jyväskylä, Finland; 3Low Temperature Laboratory, Helsinki University of Technology, Helsinki, FinlandAbstract: A rapid method and instrumentation for quantification of immunochromatographic tests (ICT) are described. The principle and performance of the method was demonstrated by measuring the levels of human chorionic gonadotropin (hCG) present in urine. The test format was a sandwich assay using two distinct monoclonal antib…

2020

Background Evidence suggests that mobile health app use is beneficial for the prevention and management of type 2 diabetes (T2D) and its associated complications; however, population-based research on specific determinants of health app use in people with and without T2D is scarce. Objective This cross-sectional study aimed to provide population-based evidence on rates and determinants of health app use among adults with and without T2D, thereby covering a prevention perspective and a diabetes management perspective, respectively. Methods The study population included 2327 adults without a known diabetes diagnosis and 1149 adults with known T2D from a nationwide telephone survey in Germany…

Monitoring of the action of drugs in melanoma cells by dynamic laser speckle

2014

Abstract. This work presents the development of a protocol based on the dynamic laser speckle designed tomonitor the reaction of cancer cells of line MEL-RC08 to the application of the drug Colcemid in two differentconcentrations: 0.2 and 0.4 μg∕mL. The protocol was designed using the forward scattering approach with anHe-Ne laser of 632.8 nm illuminating the samples, a control, and two variations of Colcemid, being monitoredalong 8 h. The data were analyzed numerically in the time and in the frequency domain, and the results pre-sented the ability of the technique to monitor the action of the drug, particularly Colcemid (0.4 μg∕mL). © 2014Society of Photo-Optical Instrumentation Engineers …

Towards noncontact skin melanoma selection by multispectral imaging analysis

2011

A clinical trial comprising 334 pigmented and vascular lesions has been performed in three Riga clinics by means of multispectral imaging analysis. The imaging system Nuance 2.4 (CRi) and self-developed software for mapping of the main skin chromophores were used. Spe- cific features were observed and analyzed for malignant skin melanomas: notably higher absorbance (especially as the difference of optical density relative to the healthy skin), uneven chromophore distribution over the lesion area, and the possibility to select the "melanoma areas" in the correla- tion graphs of chromophores. The obtained results indicate clinical potential of this technology for noncontact selec- tion of mel…

Assessment of regional ventilation distribution: comparison of vibration response imaging (VRI) with electrical impedance tomography (EIT)

2013

BACKGROUND: Vibration response imaging (VRI) is a bedside technology to monitor ventilation by detecting lung sound vibrations. It is currently unknown whether VRI is able to accurately monitor the local distribution of ventilation within the lungs. We therefore compared VRI to electrical impedance tomography (EIT), an established technique used for the assessment of regional ventilation. METHODOLOGY/PRINCIPAL FINDINGS: Simultaneous EIT and VRI measurements were performed in the healthy and injured lungs (ALI; induced by saline lavage) at different PEEP levels (0, 5, 10, 15 mbar) in nine piglets. Vibration energy amplitude (VEA) by VRI, and amplitudes of relative impedance changes (rel.ΔZ) …

Novel technologies to detect atelectotrauma in the injured lung

2010

ABSTRACTCyclical recruitment and derecruitment of lung parenchyma (R/D) remains a serious problem in ALI/ARDS patients, defined as atelectotrauma. Detection of cyclical R/D to titrate the optimal respiratory settings is of high clinical importance. Image-based technologies that are capable of detecting changes of lung ventilation within a respiratory cycle include dynamic computed tomography (dCT), synchrotron radiation computed tomography (SRCT), and electrical impedance tomography (EIT). Time-dependent intra-arterial oxygen tension monitoring represents an alternative approach to detect cyclical R/D, as cyclical R/D can result in oscillations of PaO2 within a respiratory cycle. Continuous…