Recommendations for standardised screw pull-out from polyurethane foam - The influence of density variations of the test foam and the insertion method

2022 ◽  
pp. 103750
Author(s):  
Martin Weidling ◽  
Toni Wendler ◽  
Stephan Schoenfelder ◽  
Christoph-E. Heyde
Keyword(s):  
Polyurethane Foam ◽  
Pull Out ◽  
Insertion Method

Comparison of pull-out resistance of Kirschner wires and Imex™ miniature interface fixation half pins in polyurethane foam

2002 ◽  
Vol 15 (01) ◽  
pp. 18-22 ◽  
Author(s):  
C. W. Smith ◽  
J. Harari ◽  
S. Marretta ◽  
G. J. Pijanowski ◽  
D. J. Schaeffer ◽  
...  
Keyword(s):  
Polyurethane Foam ◽  
Long Bone ◽  
Bony Union ◽  
Kirschner Wires ◽  
Bone Interface ◽  
Bone Model ◽  
Pull Out ◽  
Pull Out Strength

SummaryThe pin-bone interface is critical in maintaining a stable external skeletal fixator to allow bony union and prevent complications related to loose pins (3, 7, 13, 14, 16, 17). Threaded pins have increased pull-out strength in comparison to smooth pins and have improved the bone-pin interface (1, 2, 4, 12, 16, 21). Pull-out strengths were compared between smooth Kirschner size pins and Imex™ Miniature Interface Fixation Half Pins in a polyurethane foam bone model. The negative profile end threaded pins had significantly higher pull-out strengths (p <0.001) than smooth pins. Increasing the diameter of the pin and the length of engagement also increased the pull-out strengths of both pin types. Improving the pull-out strength of pins should minimize morbidity of external skeletal fixators used in repair of mandibular/maxillary fractures or long bone repairs on small and exotic patients.

scholarly journals An In Vitro Evaluation, on Polyurethane Foam Sheets, of the Insertion Torque (IT) Values, Pull-Out Torque Values, and Resonance Frequency Analysis (RFA) of NanoShort Dental Implants

Polymers ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 1020 ◽  
Author(s):  
Luca Comuzzi ◽  
Giovanna Iezzi ◽  
Adriano Piattelli ◽  
Margherita Tumedei
Keyword(s):  
Resonance Frequency ◽  
Polyurethane Foam ◽  
Frequency Analysis ◽  
Insertion Torque ◽  
Resonance Frequency Analysis ◽  
Pull Out ◽  
In Vitro Investigation ◽  
Torque Values ◽  
Pull Out Strength

Objectives: The aim of this study was to investigate, in polyurethane foam sheets, the primary implant stability of a NanoShort implant compared to a self-condenser implant and to a standard, conventional implant. Materials and Methods: Three implant designs were evaluated in the present in vitro investigation: The Test implant (NanoShort), the Control A implant (self-condenser), and the Control B implant (standard design). The study was conducted by comparing the insertion torque values, the pull-out strength values, and the resonance frequency analysis (RFA) values of the Test and Control A and B implants inserted in polyurethane foam models of different thicknesses and densities. The foam densities were 10, 20, and 30 pounds per cubic foot (pcf). Three thicknesses of polyurethane foams (1, 2, 3 mm) were evaluated for a total of 640 experimental sites. Results: The Pearson correlation showed a moderate/strong correlation between all study groups (r > 0.3) for insertion torque and pull-out strength levels. Increased stability of the Test implants was obtained in 3 mm polyurethane sheets. The 2.5 and 3.5 mm Test implants presented good stability in 3 mm polyurethane sheets of 20–30 pcf densities. The Control implants showed better results compared to the Test implants in 1, 2, and 3 mm polyurethane sheets with densities of 10, 20, and 30 pcf. Conclusions: The NanoShort dental implant evaluated in this in vitro study showed a high level of stability in some experimental conditions, and could represent a useful tool, especially in the posterior mandible, as an alternative to vertical augmentation procedures.

scholarly journals Short vs. Standard Length Cone Morse Connection Implants: An In Vitro Pilot Study in Low Density Polyurethane Foam

Symmetry ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 1349 ◽  
Author(s):  
Luca Comuzzi ◽  
Margherita Tumedei ◽  
Adriano Piattelli ◽  
Giovanna Iezzi
Keyword(s):  
Polyurethane Foam ◽  
Standard Length ◽  
Titanium Implants ◽  
Insertion Torque ◽  
Conical Shape ◽  
Pull Out ◽  
Short Implants ◽  
In Vitro Investigation ◽  
Torque Values

The aim of the investigation was to evaluate the insertion torque, pull-out torque and implant stability quotient (ISQ) of short implants (SI) and standard length implants (ST) inserted into linearly elastic and constitutive isotropic symmetry polyurethane foam blocks. Short dental titanium implants with a Cone Morse connection and a conical shape (test implants: Test Implant A—diameter 5.5 mm and length 6 mm) (Test Implant B—diameter 5.5 mm and length 5 mm) were used for the present in vitro investigation. ST implants (4 mm diameter and 10 mm length), with a Cone Morse connection and a conical shape, were used as Control Implant A and as Control Implants B. These two latter implants had a different macro design. A total of 20 implants (5 Test A, 5 Test B, 5 Control A and 5 Control B) were used for the present research. The results were similar when comparing the Test A and Test B implants. The test implants had very good stability in polyurethane 14.88–29.76 kgm3 density blocks. The insertion torque values were very high for both types of test implant (25–32 Ncm on 14.88 kgm blocks, and up to 45 Ncm in 29.76 kgm3 blocks). The pull-out test values were very similar to the insertion torque values. The ISQ values were significantly high with 75–80 in 14.88 kgm3 blocks, and 78–83 in 29.76 kgm3 blocks. No differences were found in the values of the Control A and Control B implants. In both these implants, the insertion torque was quite low in the 14.88 kgm3 blocks (16–28 Ncm). Better results were found in the 29.76 kgm3 blocks. The pull-out values for these control implants were slightly lower than the insertion torque values. High ISQ values were found in both control implants (57–80). When comparing SI and ST implants, the SI had a similar if not better performance in low quality polyurethane foam blocks (14.88–29.76 kgm), corresponding to D3 and D4 bone.

scholarly journals Optimal interference of the tibial component of the cementless Oxford Unicompartmental Knee Replacement

2018 ◽  
Vol 7 (3) ◽  
pp. 226-231 ◽  
Author(s):  
S. Campi ◽  
S. J. Mellon ◽  
D. Ridley ◽  
B. Foulke ◽  
C. A. F. Dodd ◽  
...  
Keyword(s):  
Polyurethane Foam ◽  
Knee Replacement ◽  
Tibial Component ◽  
Testing Machine ◽  
Unicompartmental Knee Replacement ◽  
Materials Testing ◽  
Interference Fit ◽  
Pull Out ◽  
Damage And Fracture ◽  
Unicompartmental Knee

Objectives The primary stability of the cementless Oxford Unicompartmental Knee Replacement (OUKR) relies on interference fit (or press fit). Insufficient interference may cause implant loosening, whilst excessive interference could cause bone damage and fracture. The aim of this study was to identify the optimal interference fit by measuring the force required to seat the tibial component of the cementless OUKR (push-in force) and the force required to remove the component (pull-out force). Materials and Methods Six cementless OUKR tibial components were implanted in 12 new slots prepared on blocks of solid polyurethane foam (20 pounds per cubic foot (PCF), Sawbones, Malmo, Sweden) with a range of interference of 0.1 mm to 1.9 mm using a Dartec materials testing machine HC10 (Zwick Ltd, Herefordshire, United Kingdom) . The experiment was repeated with cellular polyurethane foam (15 PCF), which is a more porous analogue for trabecular bone. Results The push-in force progressively increased with increasing interference. The pull-out force was related in a non-linear fashion to interference, decreasing with higher interference. Compared with the current nominal interference, a lower interference would reduce the push-in forces by up to 45% (p < 0.001 One way ANOVA) ensuring comparable (or improved) pull-out forces (p > 0.05 Bonferroni post hoc test). With the more porous bone analogue, although the forces were lower, the relationship between interference and push-in and pull-out force were similar. Conclusions This study suggests that decreasing the interference fit of the tibial component of the cementless OUKR reduces the push-in force and can increase the pull-out force. An optimal interference fit may both improve primary fixation and decrease the risk of fracture. Cite this article: S. Campi, S. J. Mellon, D. Ridley, B. Foulke, C. A. F. Dodd, H. G. Pandit, D. W. Murray. Optimal interference of the tibial component of the cementless Oxford Unicompartmental Knee Replacement. Bone Joint Res 2018;7:226–231. DOI: 10.1302/2046-3758.73.BJR-2017-0193.R1.

Validation of canine cancellous and cortical polyurethane foam bone models

2002 ◽  
Vol 15 (04) ◽  
pp. 200-204 ◽  
Author(s):  
S. C. Kennedy ◽  
A. L. Johnson ◽  
G. J. Pijanowski ◽  
N. Ehrhart ◽  
D. Schaeffer ◽  
...  
Keyword(s):  
Cortical Bone ◽  
Polyurethane Foam ◽  
Bone Mineral ◽  
Cancellous Bone ◽  
Bone Screws ◽  
Synthetic Bone ◽  
Pull Out ◽  
Cortical Density ◽  
Bone Cortex ◽  
Implant Testing

SummaryThe purpose of this study was to develop standard canine cortical and cancellous polyurethane foam (PUF) bone models. Canine cancellous and cortical bone mineral densities were determined with dual-energy-x-ray absorptiometry (DXA). Polyurethane foam was cast in two densities, corresponding to the predetermined canine cancellous and cortical bone mineral densities for use as synthetic bone models. Cancellous bone screws (4.0 mm and 6.5 mm) were extracted from both canine cancellous bone segments and blocks of cancellous density PUF. Cortex bone screws (3.5 mm and 4.5 mm) were extracted from both canine cortical bone segments and blocks of cortical density PUF. There was not any difference in the cancellous screw pull-out forces between cancellous density PUF and canine cancellous bone. Cortex screw pull-out forces were significantly less for cortical density PUF than for canine cortical bone. Cancellous density PUF makes an excellent cancellous bone model for use in implant testing.

The influence of heat treatment on the fiber/matrix interface in a SiC-reinforced glassceramic

1988 ◽  
Vol 46 ◽  
pp. 742-743
Author(s):  
E. Bischoff ◽  
O. Sbaizero
Keyword(s):  
Heat Treatment ◽  
Aluminum Silicate ◽  
Lithium Aluminum ◽  
Interfacial Region ◽  
Specimen Preparation ◽  
Crack Wake ◽  
Pull Out ◽  
Annealed Material ◽  
Ultrasonic Drilling ◽  
Fiber Matrix Interface

Fiber or whisker reinforced ceramics show improved toughness and strength. Bridging by intact fibers in the crack wake and fiber pull-out after failure contribute to the additional toughness. These processes are strongly influenced by the sliding and debonding resistance of the interfacial region. The present study examines the interface in a laminated 0/90 composite consisting of SiC (Nicalon) fibers in a lithium-aluminum-silicate (LAS) glass-ceramic matrix. The material shows systematic changes in sliding resistance upon heat treatment.As-processed samples were annealed in air at 800 °C for 2, 4, 8, 16 and 100 h, and for comparison, in helium at 800 °C for 4 h. TEM specimen preparation of as processed and annealed material was performed with special care by cutting along directions having the fibers normal and parallel to the section plane, ultrasonic drilling, dimpling to 100 pm and final ionthinning. The specimen were lightly coated with Carbon and examined in an analytical TEM operated at 200 kV.

Characterization of interfaces in CVD-coated nicalon fiber-reinforced SiC

1989 ◽  
Vol 47 ◽  
pp. 556-557
Author(s):  
K.L. More ◽  
R.A. Lowden
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Chemical Vapor ◽  
Chemical Vapor Infiltration ◽  
Frictional Stress ◽  
Fiber Reinforced ◽  
Pull Out ◽  
Carbon Coated ◽  
Fiber Matrix

The mechanical properties of fiber-reinforced composites are directly related to the nature of the fiber-matrix bond. Fracture toughness is improved when debonding, crack deflection, and fiber pull-out occur which in turn depend on a weak interfacial bond. The interfacial characteristics of fiber-reinforced ceramics can be altered by applying thin coatings to the fibers prior to composite fabrication. In a previous study, Lowden and co-workers coated Nicalon fibers (Nippon Carbon Company) with silicon and carbon prior to chemical vapor infiltration with SiC and determined the influence of interfacial frictional stress on fracture phenomena. They found that the silicon-coated Nicalon fiber-reinforced SiC had low flexure strengths and brittle fracture whereas the composites containing carbon coated fibers exhibited improved strength and fracture toughness. In this study, coatings of boron or BN were applied to Nicalon fibers via chemical vapor deposition (CVD) and the fibers were subsequently incorporated in a SiC matrix. The fiber-matrix interfaces were characterized using transmission and scanning electron microscopy (TEM and SEM). Mechanical properties were determined and compared to those obtained for uncoated Nicalon fiber-reinforced SiC.

Advances in ultramicrotomy for physical sciences applications

1993 ◽  
Vol 51 ◽  
pp. 710-711
Author(s):  
G. McMahon ◽  
T. Malis
Keyword(s):  
Particle Surface ◽  
Zeolite Catalysts ◽  
Physical Sciences ◽  
Pull Out ◽  
Large Particles ◽  
Novel Applications ◽  
Metal Wires ◽  
Frequent Problem ◽  
Specific Orientation ◽  
Diamond Knife

As with all techniques which are relatively new and therefore underutilized, diamond knife sectioning in the physical sciences continues to see both developments of the technique and novel applications.Technique Developments Development of specific orientation/embedding procedures for small pieces of awkward shape is exemplified by the work of Bradley et al on large, rather fragile particles of nuclear waste glass. At the same time, the frequent problem of pullout with large particles can be reduced by roughening of the particle surface, and a proven methodology using a commercial coupling agent developed for glasses has been utilized with good results on large zeolite catalysts. The same principle (using acid etches) should work for ceramic fibres or metal wires which may only partially pull out but result in unacceptably thick sections. Researchers from the life sciences continue to develop aspects of embedding media which may be applicable to certain cases in the physical sciences.

Actual procedures of diagnostics and treatments of crural venous ulcer in specialized German praxis and clinics

Phlebologie ◽  
2009 ◽  
Vol 38 (02) ◽  
pp. 77-82 ◽  
Author(s):  
P. Altmeyer ◽  
M. Stücker ◽  
S. Reich-Schupke
Keyword(s):  
Annual Meeting ◽  
Polyurethane Foam ◽  
Surgical Therapy ◽  
Compression Therapy ◽  
German Society ◽  
Venous Ulcer ◽  
Ulcus Cruris ◽  
Wound Dressings

Summary Background: To evaluate the implementation of the guidelines of the German Society of Phlebology for venous crural ulcer a survey was conducted during the annual meeting of the German Society of Phlebology 2008 in Bochum. Methods: All 719 medical participants got an anonymized questionnaire asking for supply of crural ulcer in their institution. Results: The recurrent 66 questionnaires (9.2%) were filled by colleagues from practice or hospital, mostly surgeons, dermatologists, phlebologists and vascular surgeons. As basic diagnostics vein doppler (56.1%), duplex (75.8%) or measurement of brachial-ankleindex (83.3%) were performed. Compression therapy is used in all institutions. Mainly used wound dressings are polyurethane foam dressings, alginates, hydrocolloids and silver dressings. About 2/3 conduct surgical therapy of ulcers. Conclusion: Supply of ulcus cruris by the participants of the annual meeting of the DGP corresponds mainly, but not in all aspects to the guidelines. Further efforts for a spread of the guidelines are necessary.

Interfacial interactions of polyurethane foam systems with inorganic fillers

2016 ◽  
Vol 2 (2) ◽  
pp. 49-53
Author(s):  
M. A. Ksenofontov ◽  
L. E. Ostrovskaya ◽  
E. Yu. Bobkova ◽  
V. S. Vasil`eva ◽  
T. G. Pavlukevich
Keyword(s):  
Polyurethane Foam ◽  
Interfacial Interactions ◽  
Inorganic Fillers
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