In vitro biomechanical testing of different configurations of acrylic external skeletal fixator constructs

2015 ◽  
Vol 28 (04) ◽  
pp. 227-233 ◽  
Author(s):  
S. K. Tyagi ◽  
P. Kinjavdeka ◽  
Sharma Amarpal ◽  
A. M. Pawde ◽  
T. Srivastava ◽  
...  
Keyword(s):  
High Density Polyethylene ◽  
Bone Fractures ◽  
Testing Machine ◽  
Biomechanical Testing ◽  
Bending Moment ◽  
Biomechanical Properties ◽  
Clinical Situation ◽  
High Density ◽  
Significant Difference

SummaryObjective: To evaluate the in vitro biomechanical properties of four different configurations of acrylic external skeletal fixator constructs.Materials and methods: Simulated bone constructs were prepared using two segments of 20 mm ultra-high-density polyethylene rods with a gap of 5 mm. The full pins (1.5 mm) were passed through the proximal and distal segments of ultra-high-density polyethylene rods, in the same plane, parallel to each other in configuration U, and were crossed in the M1, M2 and C configurations at a 90° angle to each other. Configuration U was a single bilateral uniplanar construct, M1 was a double orthogonal bilateral construct, M2 was a double orthogonal bilateral construct with proximal and distal connecting articulations, and C was a double orthogonal bilateral construct with proximal and distal circumferential articulations. Temporary scaffolds of different external skeletal fixator configurations were constructed using commercially available polyvinyl chloride pipes (20 mm) connected and secured to the fixation pins at a fixed distance from the rods. Acrylic powder (polymer) mixed with liquid (monomer) was poured into the pipes and allowed to solidify to form the side bars and rings. The external skeletal fixator constructs were then subjected to axial compression, cranio-caudal three-point bending and torsion (n = 4 each) using a universal testing machine. Mechanical parameters, namely stress, strain, modulus of elasticity, stiffness and bending moment of fixator constructs, were determined from load-displacement curves.Results: Configuration U was the weakest and configuration C was the strongest under all the testing modes. Under compression, the M1, M2 and C configurations were similar. Under bending, a significant difference was observed among the uniplanar, multi -planar and circular configurations with no difference between M1 and M2. However, under torsion, all the external skeletal fixator configurations differed significantly.Clinical significance: The freeform external skeletal fixator using acrylic as a replacement for a metallic bar may be useful to treat bone fractures and luxations in small animals, as it is mechanically strong, lightweight, economical, and pins can be passed from any direction depending upon the clinical situation.

scholarly journals Comparative Evaluation of Fracture Resistance of Endodontically Treated Teeth Restored with Resin Fiber Post and Stainless Steel Post: An In Vitro Study

2015 ◽  
Vol 03 (02) ◽  
pp. 080-084
Author(s):  
Vijay Singh ◽  
Poonam Bogra ◽  
Saurabh Gupta ◽  
Navneet Kukreja ◽  
Neha Gupta
Keyword(s):  
Stainless Steel ◽  
Fracture Resistance ◽  
Testing Machine ◽  
Compressive Force ◽  
Control Group ◽  
Fiber Post ◽  
Endodontically Treated Teeth ◽  
Group I ◽  
Significant Difference

AbstractFracture resistance of endodontically treated teeth restored with post. Aims: This study aims to compare the fracture resistance of endodontically treated teeth restored with resin fiber and stainless steel post. Commercially available prefabricated resin fiber post(Dentsply Maillefer Easy Post), prefabricated stainless steel post(Coltene/Whaledent Parapost) were used. Methods and Material: Forty five maxillary central incisors were obturated and divided into 3 groups: Control Group (Group I) without any post (n = 15), Resin Fiber Post Group (Group II) (n = 15) and Stainless Steel Post Group (Group III) (n = 15). In all Groups except control group, post space was prepared; a post was cemented, and a core build-up was provided. All the specimens were subjected to compressive force under a universal testing machine until fracture. Statistical analysis used: The results were analyzed using the variable analysis test (ANOVA). Results: One-way analysis of variance revealed significant difference among test groups. The control group demonstrated highest fracture resistance (925.2183 N), followed by the resin fiber post group (486.7265 N) and stainless steel post group (423.539N). Conclusions: Teeth restored with resin fiber post showed higher fracture resistance values than prefabricated stainless steel post.

scholarly journals Frictional Characteristics of the Newer Low-friction Elastomeric Ligatures

2016 ◽  
Vol 6 (1) ◽  
pp. 19-23
Author(s):  
Amol Mhatre ◽  
VK Ravindranath ◽  
Sachin Doshi ◽  
Girish Karandikar ◽  
PS Vivek
Keyword(s):  
Testing Machine ◽  
Frictional Resistance ◽  
Minimal Amount ◽  
New Delhi ◽  
Low Friction ◽  
Significant Difference ◽  
Group A ◽  
Group B ◽  
New Generation

ABSTRACT Aim The aim of this in vitro study was to investigate the efficiency of the new generation of elastomeric ligatures with innovative designs (SlideTM and AlastiKTM Easy-to-Tie) in reducing frictional resistance (FR) during sliding mechanics as compared with conventional ligatures. Materials and Methods Sixty ligature samples divided into four groups were used for the study. Group A: QuiK-StiK™ (3M Unitek, Monrovia, CA, USA), Group B: AlastiK™ Easy-to-Tie (3M Unitek, Monrovia, CA, USA), Group C: Slide™ (Leone, Firenze, Italy), and Group D: SS ligatures 0.010” (Libral Traders, New Delhi, India). Universal Testing Machine, Instron was used for measuring FR at the bracket-wire interface. Results There was statistically significant difference in FR among all the four groups of ligatures tested (p < 0.001). Slide ligatures produced the least amount of FR followed by SS ligatures, Easy-to-Tie, and QuiK-StiK in the increasing order of the FR values registered. Conclusion SlideTM ligatures may represent a valid alternative to passive self-ligating brackets when minimal amount of friction is desired. Angulation introduced into the elastomeric ligatures reduces the friction in comparison to conventional elastomeric ligatures. How to cite this article Vivek PS, Ravindranath VK, Karandikar G, Doshi S, Mhatre A, Sonawane M. Frictional Characteristics of the Newer Low-friction Elastomeric Ligatures. J Contemp Dent 2016;6(1):19-23.

Effect of Alkaline Treatment on Sawdust Reinforced High Density Polyethylene Composite under Wide Strain Rate

2016 ◽  
Vol 840 ◽  
pp. 103-107 ◽  
Author(s):  
Haliza Jaya ◽  
Mohd Firdaus Omar ◽  
Hazizan Md Akil ◽  
Zainal Arifin Ahmad ◽  
Nik Noriman Zulkepli
Keyword(s):  
Surface Roughness ◽  
Strain Rate ◽  
Dynamic Loading ◽  
High Density Polyethylene ◽  
Split Hopkinson Pressure Bar ◽  
Alkali Treatment ◽  
Testing Machine ◽  
High Density ◽  
Rate Condition ◽  
Static And Dynamic Loading

In this study, the alkali treatment of sawdust using different concentration of sodium hydroxide (NaOH) is performed. The purpose of this treatment is to improve the filler-matrix compatibility, thus, enhance the properties of tested specimens under various strain rate condition. The outcome shows the alkali treated sawdust did improve its surface roughness through reduction of sawdust diameter. With this increasing of surface roughness, it will enhance the compatibility between sawdust filler and HDPE matrix. For comparison purpose, the treated and untreated sawdust filler were reinforce in High Density Polyethylene (HDPE) matrix and have been test under static and dynamic loading using Universal Testing Machine (UTM) and Split Hopkinson Pressure Bar (SHPB) apparatus. The results indicate that the stiffness and compression strength properties were improved on treated sawdust composites for both static and dynamic loading compare to untreated sawdust composites.

scholarly journals “Ormocer an innovative technology”: A replacement for conventional cements and veneer? A comparative in vitro analysis

2017 ◽  
Vol 11 (01) ◽  
pp. 058-063 ◽  
Author(s):  
Vini Rajeev ◽  
Rajeev Arunachalam ◽  
Sanjna Nayar ◽  
P. R. Arunima ◽  
Sivadas Ganapathy ◽  
...  
Keyword(s):  
Bond Strength ◽  
Testing Machine ◽  
In Vitro Study ◽  
Sem Analysis ◽  
Innovative Technology ◽  
Group I ◽  
Luting Cement ◽  
Significant Difference ◽  
Vitro Analysis

ABSTRACT Objective: This in vitro study was designed to assess shear bond strength (SBS) of ormocer flowable (OF) resin as a luting agent, ormocer as an indirect veneer material with portrayal of modes of failures using scanning electron microscope (SEM). Materials and Methods: Sixty maxillary central incisors were divided into Group I, II, and III with 20 samples each based on luting cement used. They were OF, self-adhesive (SA) cement, and total etch (TE) cement. These groups were subdivided into “a” and “b” of ten each based on the type of veneering materials used. Veneer discs were fabricated using Ormocer restorative (O) and pressable ceramic (C). Specimens were thermocycled and loaded under universal testing machine for SBS. The statistical analysis was done using one-way ANOVA post hoc Tukey honest significant difference method. Results: A significant difference was observed between the Groups I and II (P < 0.05). The highest mean bond strength when using ormocer veneer was obtained with the Group Ia (19.11 ± 1.92 Mpa) and lowest by Group IIa (8.1 ± 1.04 Mpa), whereas the highest mean bond strength while using ceramic veneer was of similar range for Group Ib (18.04 ± 4.08 Mpa) and Group IIIb (18.07 ± 1.40 Mpa). SEM analysis revealed OF and TE presented mixed type of failure when compared with SA where failure mode was totally adhesive. Conclusion: OF was found equally efficient like TE. Bond strength of ormocer as a veneer was not inferior to ceramic making it one of the promising additions in the field of dentistry.

Kinematic and Kinetic Comparison of Fresh Frozen and Thiel-Embalmed Human Feet for Suitability for Biomechanical Educational and Research Settings

2019 ◽  
Vol 109 (2) ◽  
pp. 113-121 ◽  
Author(s):  
Alfred Gatt ◽  
Pierre Schembri-Wismayer ◽  
Nachiappan Chockalingam ◽  
Cynthia Formosa
Keyword(s):  
Human Subjects ◽  
Biomechanical Testing ◽  
Biomechanical Properties ◽  
Kinetic Properties ◽  
Foot Pressure ◽  
Human Foot ◽  
Observational Study Design ◽  
Fresh Frozen ◽  
Research And Education

Background: In vitro biomechanical testing of the human foot often involves the use of fresh frozen cadaveric specimens to investigate interventions that would be detrimental to human subjects. The Thiel method is an alternative embalming technique that maintains soft-tissue consistency similar to that of living tissue. However, its suitability for biomechanical testing is unknown. Thus, the aim of this study was to determine whether Thiel-embalmed foot specimens exhibit kinematic and kinetic biomechanical properties similar to those of fresh frozen specimens. Methods: An observational study design was conducted at a university biomechanics laboratory. Three cadavers had both limbs amputated, with one being fresh frozen and the other preserved by Thiel's embalming. Each foot was tested while undergoing plantarflexion and dorsiflexion in three states: unloaded and under loads of 10 and 20 kg. Their segment kinematics and foot pressure mapping were assessed simultaneously. Results: No statistically significant differences were detected between fresh frozen and Thiel-embalmed sample pairs regarding kinematics and kinetics. Conclusions: These findings highlight similar kinematic and kinetic properties between fresh frozen and Thiel-embalmed foot specimens, thus possibly enabling these specimens to be interchanged due to the latter specimens' advantage of delayed decomposition. This can open innovative opportunities for the use of these specimens in applications related to the investigation of dynamic foot function in research and education.

In vitro evaluation of biocompatibility of beta-tricalcium phosphate-reinforced high-density polyethylene; an orthopedic composite

2005 ◽  
Vol 75A (1) ◽  
pp. 14-22 ◽  
Author(s):  
S. SH. Homaeigohar ◽  
M. A. Shokrgozar ◽  
A. Yari Sadi ◽  
A. Khavandi ◽  
J. Javadpour ◽  
...  
Keyword(s):  
Tricalcium Phosphate ◽  
High Density Polyethylene ◽  
High Density ◽  
In Vitro Evaluation ◽  
Beta Tricalcium Phosphate

Evaluating Dentin Surface Treatments for Resin-Modified Glass Ionomer Restorative Materials

2013 ◽  
Vol 38 (4) ◽  
pp. 429-438 ◽  
Author(s):  
TA Imbery ◽  
A Namboodiri ◽  
A Duncan ◽  
R Amos ◽  
AM Best ◽  
...  
Keyword(s):  
Testing Machine ◽  
In Vitro Study ◽  
Positive Control ◽  
Negative Control ◽  
Surface Treatments ◽  
Band Matrices ◽  
Dentin Surface ◽  
Occlusal Surfaces ◽  
Significant Difference

SUMMARY This in vitro study evaluated the effect of six surface treatments on the shear bond strength of three resin-modified glass ionomers (RMGIs) to dentin. Occlusal surfaces of caries-free third molars were reduced to expose only dentin. Surface treatments were smear layer intact (negative control), Cavity Conditioner, EDTA, Ketac Primer, Self Conditioner, and etching with 35% phosphoric acid followed by the application of Optibond Solo Plus. Filtek Z250 composite resin bonded with Optibond Solo Plus served as a positive control. Conditioning agents were used according to the manufacturers' instructions. After surface treatments, Fuji II LC, Riva LC, Ketac Nano, and Filtek Z250 were placed in copper-band matrices 5 mm in diameter and 2 mm in height and were light-cured for 20 seconds. Specimens were stored in 100% humidity for 24 hours, after which they were placed in deionized water for 24 hours at 37°C. They were then tested under shear forces in an Instron Universal Testing Machine at a crosshead speed of 0.5 mm/min. A two-way analysis of variance and Tukey honestly significant difference statistical analyses (p&lt;0.05) indicated significant interaction between RMGIs and conditioning agents. Acid etching followed by Optibond Solo Plus provided highest bond strengths for all three RMGIs, which were not statistically different from the positive control.

scholarly journals Biomechanical properties of a novel biodegradable magnesium-based interference screw

2016 ◽  
Vol 8 (2) ◽  
Author(s):  
Marco Ezechieli ◽  
Hanna Meyer ◽  
Arne Lucas ◽  
Patrick Helmecke ◽  
Christoph Becher ◽  
...  
Keyword(s):  
Cruciate Ligament ◽  
Testing Machine ◽  
Biomechanical Testing ◽  
Maximum Load ◽  
Biomechanical Properties ◽  
Interference Screw ◽  
Biomechanical Analysis ◽  
Interference Screws ◽  
Standard Implant ◽  
Biodegradable Magnesium

Magnesium-based interference screws may be an alternative in anterior/posterior cruciate ligament reconstruction. The well-known osteoconductive effects of biodegradable magnesium alloys may be useful. It was the purpose of this study to evaluate the biomechanical properties of a magnesium based interference screw and compare it to a standard implant. A MgYREZr-alloy interference screw and a standard implant (Milagro®; De Puy Mitek, Raynham, MA, USA) were used for graft fixation. Specimens were placed into a tensile loading fixation of a servohydraulic testing machine. Biomechanical analysis included pretensioning of the constructs at 20 N for 1 min following cyclic pretensioning of 20 cycles between 20 and 60 N. Biomechanical elongation was evaluated with cyclic loading of 1000 cycles between 50 and 200 N at 0.5 Hz. Maximum load to failure was 511.3±66.5 N for the Milagro® screw and 529.0±63.3 N for magnesium-based screw (ns, P=0.57). Elongations after preload, during cyclical loading and during failure load were not different between the groups (ns, P&gt;0.05). Stiffness was 121.1±13.8 N/mm for the magnesiumbased screw and 144.1±18.4 for the Milagro® screw (ns, P=0.32). MgYREZr alloy interference screws show comparable results in biomechanical testing to standard implants and may be an alternative for anterior cruciate reconstruction in the future.

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