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Effects of Thermal Cycling on Surface Hardness, Diametral Tensile Strength and Porosity of an Organically Modified Ceramic (ORMOCER)-Based Visible Light Cure Dental Restorative Resin
Published in P. Mereena Luke, K. R. Dhanya, Didier Rouxel, Nandakumar Kalarikkal, Sabu Thomas, Advanced Studies in Experimental and Clinical Medicine, 2021
The diametral tensile strength (DTS) was determined as described before [8] using a Universal Testing Machine (Instron, Model 1011, UK). DTS was calculated using the following equation: where, P is the load at break in Newtons, D is the diameter and L is the thickness of the specimen in mm. Statistical analysis was carried out using ANOVA (analysis of variance) single factor to determine significant changes (P < 0.05).
Mathematical Modeling and Analysis of Soft Tissue Viscoelasticity and Dielectric Relaxation
Published in A. Bakiya, K. Kamalanand, R. L. J. De Britto, Mechano-Electric Correlations in the Human Physiological System, 2021
A. Bakiya, K. Kamalanand, R. L. J. De Britto
The various mechanical properties of biological soft tissues include density, Young’s modulus or elastic modulus, viscous modulus or loss modulus, breaking stress, breaking strain, hardness, etc. These properties can be assessed using suitable mechanical tests and instruments such as the universal testing machine, the indentation device for measuring hardness and impact tester. The common electrical properties of the tissues are its resistivity, conductivity, permittivity and permeability. Similar to other material properties, these properties also vary significantly in cases of pathologies and diseases and are useful for assessing the quality of physiological systems. The thermal properties of soft tissues include thermal conductivity, thermal diffusivity, etc. and have a major influence on the functionality of the soft tissue. This book mainly deals with the mechanical, electrical and thermal along with the computation methods and models used to analyze the conditions of the tissue based on these properties.
Effect of drill speed on bone damage during drilling
Published in R.M. Natal Jorge, J.C. Reis Campos, Mário A.P. Vaz, Sónia M. Santos, João Manuel R.S. Tavares, Biodental Engineering IV, 2017
M.G.A. Fernandes, R. Natal, E.M.M. Fonseca, J.E.P.C. Ribeiro, L. Azevedo
The material parameters for the composite block material are obtained from the results of uniaxial tensile tests. The tests were carried out using an Instron 4485 universal testing machine in the Material and Strength Laboratory of Polytechnic Institute of Bragança. The mean values of Young’s modulus, initial yield stress, tangent modulus and failure strain were calculated and incorporated into the finite element model. The remaining material properties were taken from literature (Li et al. 2010; Fernandes et al. 2015). In order to reduce the computational cost and resources involved in the drilling simulations, the cutting tool was modelled as a rigid body due to their high elastic stiffness (200–240 GPa) when compared with the block material. All the material properties used in the numerical analysis are listen in Table 2.
Bond strength of orthodontic buttons on clear aligner materials
Published in Orthodontic Waves, 2021
Natnicha Pariyatdulapak, Pornkiat Churnjitapirom, Toemsak Srikhirin, Nita Viwattanatipa
The specimens were tested with a universal testing machine (Instron model 5566, Instron Corporation, Canton, MA, USA). The shear bond strength test was modified from the Lap Shear Test Method (ASTM D3163) [12], and performed with a crosshead speed of 1.27 mm/minute and a 1 kN load cell until failure. The force required to shear off the button was recorded in Newtons (N) and the shear bond strength (stress per unit area) in Megapascals (MPa) was calculated. The area of the base of the buttons was measured by taking a digital image of the button base over a standardized millimetre grid. The image was then imported into the Autocad 2004 software (Autodesk, Inc., San Rafael, CA, USA). After calibrating the image, the perimeter of the button base was drawn and the area was calculated by the software. The average button base area was 8.97 mm2 for the metal buttons and 11.25 mm2 for the plastic buttons. The shear bond strength test was performed by the same operator with no blinding.
Mechanical behaviour of a membrane made of human umbilical cord for dental bone regenerative medicine
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2020
M. Dubus, H. Kerdjoudj, L. Scomazzon, J. Sergheraert, C. Mauprivez, R. Rahouadj, A. Baldit
The mechanical quality of the samples was tested through quasi static tensile tests up to failure. The loading sequence was divided into two parts: (a) a dry test under elastic limits to avoid any damages followed by (b) a hydrated one allowing a full behaviour characterisation of the materials ([NaCl] = 9 g.L−1) at 37 °C. Five minutes were given for the sample to accommodate prior to be tested through cyclic strain loads and eventually up to failure. All loadings were performed at a 0.01 mm.s−1 velocity to remain in the quasi static framework. A Universal Testing Machine Zwicky0.5 equipped with a 10 N load cell was used to measure samples’ response. Specimens were cut to the same dimensions to get hydrated samples of: 13.79 ± 0.59 × 4.65 ± 0.57 × 0.95 ± 0.19 mm3 for the UC-membrane and 13.01 ± 0.01 × 4.39 ± 0.05 × 0.5 ± 0.01 mm3 for the Bio-Gide®. The engineering stress definition: 2004) has been also used to fit the results:
A round-robin finite element analysis of human femur mechanics between seven participating laboratories with experimental validation
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2019
Daniel Kluess, Ehsan Soodmand, Andrea Lorenz, Dieter Pahr, Michael Schwarze, Robert Cichon, Patrick A. Varady, Sven Herrmann, Bernhard Buchmeier, Christian Schröder, Stefan Lehner, Maeruan Kebbach
For loading the femur, a servohydraulic universal testing machine was used (Instron 8874 with software WaveMatrix, Instron GmbH, Darmstadt, Germany). The embedding pot with femur was clamped to the base plate of the testing machine. The test punch was brought to a preload of 50 N. During the measurement, the femur was loaded in 10 incremental stages from 200 N to 2,000 N. Each load stage was realized at a testing velocity of 100 N/s. Upon reaching the target value, each load level was held for 5 seconds in order to avoid visco-elastic phenomena, and a digital photograph was taken. After reaching the maximum force, the bone was unloaded. During the test, the traverse path and load were continuously recorded at a frequency of 50 Hz. The experiment was repeated five times.