Does Change in Thread Shape Influence the Pull Out Strength of Mini Implants? An In vitro Study

Yashwant, Aniruddh V; Dilip, S; Rajaram, Krishnaraj; Ravi, K

doi:10.7860/jcdr/2017/25774.9808

Cited by 11 publications

(12 citation statements)

References 21 publications

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“… 31 , 32 However, a biomechanical pullout test showed that trapezoidal fluted mini-implants had higher pullout strength compared with the reverse buttress thread and buttress thread. 33 In short, the results of the above FEA and biomechanical pullout studies are inconsistent, which is attributed to the varied testing setups and loading conditions of the different studies. Their results therefore need to be interpreted carefully.…”

Section: Discussionmentioning

confidence: 99%

Can barb thread design improve the pullout strength of bone screws?

Feng

Fang

et al. 2021

Bone & Joint Research

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Aims To draw a comparison of the pullout strengths of buttress thread, barb thread, and reverse buttress thread bone screws. Methods Buttress thread, barb thread, and reverse buttress thread bone screws were inserted into synthetic cancellous bone blocks. Five screw-block constructs per group were tested to failure in an axial pullout test. The pullout strengths were calculated and compared. A finite element analysis (FEA) was performed to explore the underlying failure mechanisms. FEA models of the three different screw-bone constructs were developed. A pullout force of 250 N was applied to the screw head with a fixed bone model. The compressive and tensile strain contours of the midsagittal plane of the three bone models were plotted and compared. Results The barb thread demonstrated the lowest pullout strength (mean 176.16 N (SD 3.10)) among the three thread types. It formed a considerably larger region with high tensile strains and a slightly smaller region with high compressive strains within the surrounding bone structure. The reverse buttress thread demonstrated the highest pullout strength (mean 254.69 N (SD 4.15)) among the three types of thread. It formed a considerably larger region with high compressive strains and a slightly smaller region with high tensile strains within the surrounding bone structure. Conclusion Bone screws with a reverse buttress thread design will significantly increase the pullout strength. Cite this article: Bone Joint Res 2021;10(2):105–112.

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Section: Discussionmentioning

confidence: 99%

Can barb thread design improve the pullout strength of bone screws?

Feng

Fang

et al. 2021

Bone & Joint Research

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“…The pull-out test of integrated implants has been widely adopted to test osseointegration strength [11,12,13,14,15]. However, we used rotating force instead of pull-out force because the removal direction for the pull-out test could be nonparallel to the long axis of the implant, imposing unintentional lateral force on the implant, which can introduce measurement error.…”

Section: Discussionmentioning

confidence: 99%

A Clue to the Existence of Bonding between Bone and Implant Surface: An In Vivo Study

et al. 2019

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We evaluated the shear bond strength of bone–implant contact, or osseointegration, in the rabbit tibia model, and compared the strength between grades 2 and 4 of commercially pure titanium (cp-Ti). A total of 13 grades 2 and 4 cp-Ti implants were used, which had an identical cylinder shape and surface topography. Field emission scanning electron microscopy, X-ray photoelectron spectroscopy, and confocal laser microscopy were used for surface analysis. Four grades 2 and 4 cp-Ti implants were inserted into the rabbit tibiae with complete randomization. After six weeks of healing, the experimental animals were sacrificed and the implants were removed en bloc with the surrounding bone. The bone–implant interfaces were three-dimensionally imaged with micro-computed tomography. Using these images, the bone–implant contact area was measured. Counterclockwise rotation force was applied to the implants for the measurement of removal torque values. Shear bond strength was calculated from the measured bone–implant contact and removal torque data. The t-tests were used to compare the outcome measures between the groups, and statistical significance was evaluated at the 0.05 level. Surface analysis showed that grades 2 and 4 cp-Ti implants have similar topographic features. We found no significant difference in the three-dimensional bone–implant contact area between these two implants. However, grade 2 cp-Ti implants had a higher shear bond strength than grade 4 cp-Ti implants (p = 0.032). The surfaces of the grade 2 cp-Ti implants were similar to those of the grade 4 implants in terms of physical characteristics and the quantitative amount of attachment to the bone, whereas the grade 2 surfaces were stronger than the grade 4 surfaces in the bone–surface interaction, indicating osseointegration quality.

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“…In addition, biomechanical experiments, such as those involving the use of a universal force moment sensor or robotic evaluation system for cadaveric and animal bones can provide predictive results under physiological conditions [16]. Several studies on orthopedic and dental implants have revealed various structural parameters that influence the primary stability of screw topology, including pitch, contact area, thread shapes, and cylindrical part dimensions [17][18][19].…”

Section: Introductionmentioning

confidence: 99%

Design and Development of Magnesium-Based Suture Anchor for Rotator Cuff Repair Using Finite Element Analysis and In Vitro Testing

Tang

Jang

et al. 2021

Applied Sciences

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A suture anchor is a medical device commonly used in rotator cuff repair surgery to attach tendons to the greater tuberosity of the humerus. Patient- and device-related factors, such as structural designs and poor bone density, can cause unsatisfactory clinical results. In this study, a new suture anchor design with four distinctive parameters was proposed, and the structural performance was optimized in a full factorial experimental design using finite element analysis. Two types of bone blocks—normal and osteoporotic bone—which received screw implants, were simulated to investigate the parametrical effects on various bone qualities. The prescribed motion at a constant removal velocity was used to evaluate the pullout strength. The von Mises criterion was employed in a force control simulation for topology optimization. Moreover, mechanical tests guided by ASTM-F543-17 were conducted for validation. This paper demonstrates the comprehensive process for developing a suture anchor with sufficient mechanical integrity for clinical use and clarifies the contributions of each distinctive design parameter in this application.

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Does Change in Thread Shape Influence the Pull Out Strength of Mini Implants? An In vitro Study

Cited by 11 publications

References 21 publications

Can barb thread design improve the pullout strength of bone screws?

Can barb thread design improve the pullout strength of bone screws?

A Clue to the Existence of Bonding between Bone and Implant Surface: An In Vivo Study

Design and Development of Magnesium-Based Suture Anchor for Rotator Cuff Repair Using Finite Element Analysis and In Vitro Testing

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