Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2017 Jul;47(4):238-247.
doi: 10.4041/kjod.2017.47.4.238. Epub 2017 May 26.

Effects of recycling on the biomechanical characteristics of retrieved orthodontic miniscrews

Soon-Dong Yun  1 , Sung-Hwan Choi  1 , Jung-Yul Cha  1 , Hyung-Seog Yu  1 , Kwang-Mahn Kim  2 , Jin Kim  3 , Chung-Ju Hwang  1
Affiliations

Effects of recycling on the biomechanical characteristics of retrieved orthodontic miniscrews

Soon-Dong Yun et al. Korean J Orthod. 2017 Jul.

Abstract

Objective: The aim of this study was to compare recycled and unused orthodontic miniscrews to determine the feasibility of reuse. The comparisons included both miniscrews with machined surfaces (MS), and those with etched surfaces (ES).

Methods: Retrieved MS and ES were further divided into three subgroups according to the assigned recycling procedure: group A, air-water spray; group B, mechanical cleaning; and group C, mechanical and chemical cleaning. Unused screws were used as controls. Scanning electron microscopy, energy-dispersive X-ray spectrometry, insertion time and maximum insertion torque measurements in artificial bone, and biological responses in the form of periotest values (PTV), bone-implant contact ratio (BIC), and bone volume ratio (BV) were assessed.

Results: Morphological changes after recycling mainly occurred at the screw tip, and the cortical bone penetration success rate of recycled screws was lower than that of unused screws. Retrieved ES needed more thorough cleaning than retrieved MS to produce a surface composition similar to that of unused screws. There were no significant differences in PTV or BIC between recycled and unused screws, while the BV of the former was significantly lower than that of the latter (p < 0.05).

Conclusions: These results indicate that reuse of recycled orthodontic miniscrews may not be feasible from the biomechanical aspect.

Keywords: Biomechanical characteristics; Recycling; Retrieved orthodontic miniscrew; Surface characteristics.

PubMed Disclaimer

Conflict of interest statement

The authors report no commercial, proprietary, or financial interest in the products or companies described in this article.

Figures

Figure 1
Figure 1. Schematic diagrams of orthodontic miniscrews with (A) machined and (B) etched surfaces.
Ø, Diameter.
Figure 2
Figure 2. Placement of orthodontic miniscrews in the maxilla.
Figure 3
Figure 3. Flowchart of the experiment.
Figure 4
Figure 4. Images of the recycling processes used in the present study. A, Retrieved screws; B, air-flow with glycine powder (mechanical cleaning); C, immersion in 37% phosphoric acid (10 min; chemical cleaning); and D, immersion in 6% sodium hypochlorite (15 min; chemical cleaning).
Figure 5
Figure 5. Assessment of mechanical characteristics. A, Photograph of the torque tester used in the study; B, graph showing insertion time and insertion torque.
Figure 6
Figure 6. Measurements of (A) bone–implant contact ratio (BIC), T1 + T2 + T3 (yellow line) / T4 (blue line) and (B) bone volume ratio (BV), yellow area / area within the green line. Hematoxylin and eosin staining.
Figure 7
Figure 7. Scanning electron microscopy images of the lateral side of orthodontic miniscrews with a machined surface (×80, ×200, ×500, and ×1,000). Group A, air-water spray only and distilled water irrigation; group B, mechanical cleaning; group C, mechanical cleaning + chemical cleaning; group D, unused screw (control).
Figure 8
Figure 8. Scanning electron microscopy images of the lateral side of orthodontic miniscrews with an etched surface (×80, ×200, ×500, and ×1,000). Group A, air-water spray only and distilled water irrigation; group B, mechanical cleaning; group C, mechanical cleaning + chemical cleaning; group D, unused screw (control).
Figure 9
Figure 9. Scanning electron microscopy images of the tips of orthodontic miniscrews with (A) a machined surface and (B) an etched surface (×80, ×200). Group A, air-water spray only and distilled water irrigation; group B, mechanical cleaning; group C, mechanical cleaning + chemical cleaning; group D, unused screw (control).
See this image and copyright information in PMC

Comment in

  • Reader's Forum.
    Nam JY. Nam JY. Korean J Orthod. 2017 Sep;47(5):275-276. doi: 10.4041/kjod.2017.47.5.275. Epub 2017 Jul 27. Korean J Orthod. 2017. PMID: 28861388 Free PMC article. No abstract available.

References

    1. Park HS, Kwon TG. Sliding mechanics with microscrew implant anchorage. Angle Orthod. 2004;74:703–710. - PubMed
    1. Choi SH, Jang SH, Cha JY, Hwang CJ. Evaluation of the surface characteristics of anodic oxidized miniscrews and their impact on biomechanical stability: An experimental study in beagle dogs. Am J Orthod Dentofacial Orthop. 2016;149:31–38. - PubMed
    1. Miyawaki S, Koyama I, Inoue M, Mishima K, Sugahara T, Takano-Yamamoto T. Factors associated with the stability of titanium screws placed in the posterior region for orthodontic anchorage. Am J Orthod Dentofacial Orthop. 2003;124:373–378. - PubMed
    1. Cheng SJ, Tseng IY, Lee JJ, Kok SH. A prospective study of the risk factors associated with failure of mini-implants used for orthodontic anchorage. Int J Oral Maxillofac Implants. 2004;19:100–106. - PubMed
    1. Hong SB, Kusnoto B, Kim EJ, BeGole EA, Hwang HS, Lim HJ. Prognostic factors associated with the success rates of posterior orthodontic miniscrew implants: A subgroup meta-analysis. Korean J Orthod. 2016;46:111–126. - PMC - PubMed

LinkOut - more resources