Mechanical stability of orthodontic miniscrew depends on a thread shape

Watanabe, Keiichiro; Mitchell, Bobby; Sakamaki, Tatsuya; Hirai, Yuzo; D, Kim; Deguchi, Toru; Suzuki, Masakazu; Ueda, Kanji; Tanaka, Eiji

doi:10.1016/j.jds.2021.11.010

Cited by 8 publications

(10 citation statements)

References 27 publications

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“…These devices were first described in 1997 by Kanomi [ 5 ]. The use of these systems makes it possible to perform movements that would otherwise be unachievable [ 6 ]. The use of miniscrews can be beneficial in a wide variety of orthodontic movements, such as retraction and intrusion of anterior and posterior teeth, mesialization or distalization of molars and elimination of undesirable spaces [ 7 ].…”

Section: Introductionmentioning

confidence: 99%

“…However, when compared to the devices from which they were initially derived, conventional dental implants, their failure rate is higher. Studies have reported that 10–30 percent of miniscrews fail, a figure that is significantly higher than the 10 percent of traditional implants [ 6 , 9 , 10 ]. The initial stability is often lacking in cases of inadequate cortical bone thickness.…”

Section: Introductionmentioning

confidence: 99%

“…A miniscrew is considered lost when it is no longer able to irreversibly anchor the fixed appliance, and thus is no longer resisting the forces created by reactions, leading to its removal and consequent need for replacement [ 10 ]. In its initial phase, loss can occur due to the device unscrewing, a situation that can be prevented by improving the technique and properties of the miniscrew [ 6 ]. Its loss is not, however, a one-off occurrence.…”

Section: Introductionmentioning

confidence: 99%

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Surface Treatment of Dental Mini-Sized Implants and Screws: A Systematic Review with Meta-Analysis

Figueiredo,

Travassos,

Nunes

et al. 2024

JFB

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Miniscrews are devices that allow for absolute skeletal anchorage. However, their use has a higher failure rate (10–30%) than dental implants (10%). To overcome these flaws, chemical and/or mechanical treatment of the surface of miniscrews has been suggested. There is no consensus in the current literature about which of these methods is the gold standard; thus, our objective was to carry out a systematic review and meta-analysis of the literature on surface treatments of miniscrews. The review protocol was registered (PROSPERO CRD42023408011) and is in accordance with the PRISMA guidelines. A bibliographic search was carried out on PubMed via MEDLINE, Cochrane Library, Embase and Web of Science. The initial search of the databases yielded 1684 results, with 98 studies included in the review, with one article originating from the search in the bibliographic references of the included studies. The results of this systematic review show that the protocols of miniscrew surface treatments, such as acid-etching; sandblasting, large-grit and acid-etching; photofunctionalization with ultraviolet light; and photobiomodulation, can increase stability and the success of orthodontic treatment. The meta-analysis revealed that the treatment with the highest removal torque is SLA, followed by acid-etching. On the other hand, techniques such as oxidative anodization, anodization with pre-calcification and heat treatment, as well as deposition of chemical compounds, require further investigation to confirm their effectiveness.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Surface Treatment of Dental Mini-Sized Implants and Screws: A Systematic Review with Meta-Analysis

Figueiredo,

Travassos,

Nunes

et al. 2024

JFB

View full text Add to dashboard Cite

show abstract

“…Previously, we evaluated the effects of cortical bone thickness on the mechanical stability of miniscrews in an in vitro study and found that the mechanical stability of miniscrews increased when the screws were inserted into a thicker articular bone block 29 , 30 . However, mechanical properties were found to differ meaningfully between miniscrews with different thread shapes, irrespective of the cortical bone thickness 30 .…”

Section: Introductionmentioning

confidence: 99%

Thread shape, cortical bone thickness, and magnitude and distribution of stress caused by the loading of orthodontic miniscrews: finite element analysis

Sakamaki

Watanabe

Iwasa

et al. 2022

Sci Rep

Self Cite

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Cortical bone thickness is assumed to be a major factor regulating miniscrew stability. We investigated stress distribution in two miniscrews with different thread shapes (type A and B) and in cortical bone of three different thicknesses using three-dimensional (3D) finite element (FE) models. More specifically, 3D FE models of two different miniscrews were created and placed obliquely or vertically into a cylindrical bone model representing different cortical bone thicknesses. When force was applied to the miniscrew, the stress distribution on the screw surface and in the peri-implant bone was assessed using FE methodology. Miniscrew safety was evaluated using a modified Soderberg safety factor. Screw head displacement increased with a decrease in cortical bone thickness, irrespective of screw type. The smallest minimum principal stresses on the screw surfaces remained constant in type A miniscrews on changes in cortical bone thickness. Minimum principal stresses also appeared on the cortical bone surface. Lower absolute values of minimum principal stresses were seen in type A miniscrews when placed vertically and with upward traction in obliquely placed type B miniscrews. Both miniscrews had acceptable safety factor values. Taken together, orthodontists should select and use the suitable miniscrew for each patient in consideration of bone properties.

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“…Although fracture type and surgical techniques are crucial in fixation failure of DHS treatment ( Hsu et al, 2016 ), the configurations of the lag screw are also critical factors; inner diameter, outer diameter, pitch, screw length and thread shape are main configuration parameters for orthopedics screws ( Feng et al, 2015 ; Feng et al, 2016 ; Gustafson et al, 2019 ; Kilian et al, 2019 ; Schliemann et al, 2019 ). The thread shape is the most important structure, as it can determine the mechanical environment at the bone-screw interface, and influence the biomechanical performance and osseointegration, accordingly ( Abuhussein et al, 2010 ; Alemayehu and Jeng, 2021 ; Feng et al, 2021 ; Watanabe et al, 2022 ). An FEA study found that under the same pullout force, the V-shaped thread and square thread generated less stress than the thin-thread at the bone-screw interface ( Geng et al, 2004 ).…”

Section: Introductionmentioning

confidence: 99%

Biomechanical comparison of the undercut thread design versus conventional buttress thread for the lag screw of the dynamic hip screw system

Liu

Feng²,

Zheng³

et al. 2022

Front. Bioeng. Biotechnol.

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Objective: To compare the fixation stability of the lag screw with a undercut thread design for the dynamic hip screw (DHS) system versus the lag screw with the conventional buttress thread.Methods: The lag screws with the undercut thread (a flat crest feature, a tip-facing undercut feature) and buttress thread were both manufactured. Fixation stability was investigated using cyclic compressive biomechanical testing on custom osteoporotic femoral head sawbone. The forces required for the same vertical displacement in the two types of lag screw were collected to evaluate the resistance to migration. Varus angle was measured on X-ray images to assess the ability in preventing varus collapse. Finite element analysis (FEA) was performed to analyze the stress and strain distribution at the bone-screw interface of the two types of lag screws.Results: The biomechanical test demonstrated that the force required to achieve the same vertical displacement of the lag screw with the undercut thread was significantly larger than the lag screw with conventional buttress thread (p < 0.05). The average varus angles generated by the undercut and buttress threads were 3.38 ± 0.51° and 5.76 ± 0.38°, respectively (p < 0.05). The FEA revealed that the region of high-stress concentration in the bone surrounding the undercut thread was smaller than that surrounding the buttress thread.Conclusion: The proposed DHS system lag screw with the undercut thread had higher migration resistance and superior fixation stability than the lag screw with the conventional buttress thread.

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Mechanical stability of orthodontic miniscrew depends on a thread shape

Cited by 8 publications

References 27 publications

Surface Treatment of Dental Mini-Sized Implants and Screws: A Systematic Review with Meta-Analysis

Surface Treatment of Dental Mini-Sized Implants and Screws: A Systematic Review with Meta-Analysis

Thread shape, cortical bone thickness, and magnitude and distribution of stress caused by the loading of orthodontic miniscrews: finite element analysis

Biomechanical comparison of the undercut thread design versus conventional buttress thread for the lag screw of the dynamic hip screw system

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