In-vitro evaluation of the effects of insertion and sterilization procedures on the mechanical and surface characteristics of mini screws

Abstract

Purpose

The aim of the present study was to investigate the effects of insertion and

sterilization on primary stability and to examine the mechanical and surface

characteristics of mini screws.

Materials and methods

140 miniscrews (70 Dual-Top; 70 Ortho-Easy) were divided into 3 groups. Group

1: control group, 10 miniscrews of each brand, evaluated without any primary

procedure. Group 2: 30 miniscrews of each brand, each inserted into the sawbone

once, then sterilized and tested. Group 3: 30 miniscrews of each brand, each

inserted into the sawbone twice, sterilized after each insertion and then tested. The

miniscrews were evaluated for changes in primary stability, mechanical and surface

characteristics with scanning electron microscopy (SEM) analysis, torsion tests,

maximum insertion-removal torques and vertical-horizontal pull out strength tests.

Results

The maximum insertion torque values of the unused miniscrews (Group 1) were

found to be significantly higher than those of the reused (Groups 2, 3) mini screws

(p<0.05). Removal torque, vertical-horizontal pull-out strength and torsional

strength value changes were found to be statistically insignificant. In SEM analysis,

wear and atrophy were seen on the threads of used miniscrews especially in the

apical region and the oxide layer was seen to have disappeared from some regions

of the coated miniscrews.

Conclusion

Although wear and atrophy were detected in SEM analysis of used miniscrews,

the overall primary stability and fracture torque resistance tests did not show any

significant changes after the first and second insertion and sterilization procedures.

Keywords

• Miniscrew,orthodontic mini-implant,primary stability,canning electron microscope,sterilization

References

1. Tsui WK, Chua HD, Cheung LK. Bone anchor systems for orthodontic application: a systematic review. Int J Oral Maxillofac Surg. 2012;41(11):1427-38. [CrossRef ]
2. Park H-S, Yoon D-Y, Park C-S, Jeoung S-H. Treatment effects and anchorage potential of sliding mechanics with titanium screws compared with the Tweed-Merrifield technique. Am J Orthod Dentofacial Orthop. 2008;133(4):593–600. [CrossRef ]
3. Geron S, Shpack N, Kandos S, Davidovitch M, Vardimon AD. Anchorage loss--a multifactorial response. Angle Orthod. 2003;73(6):730–7.
4. Gainsforth BL, Higley LB. A study of orthodontic anchorage possibilities in basal bone. Am J Orthod Oral Surg. 1945;31(8):406–17. [CrossRef ]
5. Chatzigianni A, Keilig L, Reimann S, Eliades T, Bourauel C. Effect of mini-implant length and diameter on primary stability under loading with two force levels. Eur J Orthod. 2011;33(4):381–7. [CrossRef ]
6. Giancotti A, Arcuri C, Barlattani A. Treatment of ectopic mandibular second molar with titanium miniscrews. Am J Orthod Dentofac Orthop. 2004;126(1):113–7. [CrossRef ]
7. Baumgaertel S. Quantitative investigation of palatal bone depth and cortical bone thickness for mini-implant placement in adults. Am J Orthod Dentofacial Orthop 2009;136(1):104–8. [CrossRef ]
8. Mattos CT, Ruellas ACDO, Elias CN. Is it possible to re-use miniimplants for orthodontic anchorage? Results of an in vitro study. Mater Res. 2010;13(4):521–5. [CrossRef ]

9. Buckthal JE, Kusy RP. Effects of cold disinfectants on the mechanical properties and the surface topography of nickel-titanium arch wires. Am J Orthod Dentofac Orthop. 1988;94(2):117–22. [CrossRef ]
10. Lee SH, Chang Y Il. Effects of recycling on the mechanical properties and the surface topography of nickel-titanium alloy wires. Am J Orthod Dentofac Orthop. 2001;120(6):654–63. [CrossRef ]
11. Bahnasi FI, Rahman ANAA, Abu-Hassan MI. The impact of recycling and repeated recycling on shear bond strength of stainless steel orthodontic brackets. Orthod Waves. 2013;72(1):16–22. [CrossRef ]
12. Kapila S, Sachdeva R. Mechanical properties and clinical applications of orthodontic wires. Am J Orthod Dentofac Orthop. 1989;96(2):100–9. [CrossRef ]
13. Acar YB, Hergel CA, Ateş MB, Küçükkeleş N. Mini-implant usage in orthodontic practice. Turkish J Orth. 2015;28(1):1-6. [CrossRef ]
14. Noorollahian S, Alavi S, Monirifard M. A processing method for orthodontic mini-screws reuse. Dent Res J (Isfahan). 2012;9(4):447–51.
15. Estelita S, Janson G, Chiqueto K, Ferreira ES. Effect of recycling protocol on mechanical strength of used mini-implants. Int J Dent. 2014;2014:424923. [CrossRef ]
16. Kim S-H, Lee S-J, Cho I-S, Kim S-K, Kim T-W. Rotational resistance of surface-treated mini-implants. Angle Orthod. 2009;79(5):899– 907. [CrossRef ]
17. Motoyoshi M, Hirabayashi M, Uemura M, Shimizu N. Recommended placement torque when tightening an orthodontic mini-implant. Clin Oral Implants Res. 2006;17(1):109–14. [CrossRef ]
18. Wilmes B, Rademacher C, Olthoff G, Drescher D. Parameters affecting primary stability of orthodontic mini-implants. J Orofac Orthop. 2006;67(3):162-74. [CrossRef ]
19. Song Y-Y, Cha J-Y, Hwang C-J. Mechanical Characteristics of Various Orthodontic Mini-screws in Relation to Artificial Cortical Bone Thickness. Angle Orthod. 2007;77(6). [CrossRef ]
20. Kim J-W, Ahn S-J, Chang Y-I. Histomorphometric and mechanical analyses of the drill-free screw as orthodontic anchorage. Am J Orthod Dentofacial Orthop. 2005;128(2):190–4. [CrossRef ]
21. Mischkowski R a, Kneuertz P, Florvaag B, Lazar F, Koebke J, Zöller JE. Biomechanical comparison of four different miniscrew types for skeletal anchorage in the mandibulo-maxillary area. Int J Oral Maxillofac Surg. 2008;37(10):948–54. [CrossRef ]
22. Carano A, Lonardo P, Velo S, Incorvati C. Mechanical properties of three different commercially available miniscrews for skeletal anchorage. Prog Orthod. 2005;6(1):82–97.
23. Kido H, Schulz E, Kumar A, Lozada J. Implant diameter and bone density: effect on initial stability and pull-out resistance. J Oral Implantol. 1997;23:163–9.
24. Pithon MM, Nojima MG, Nojima LI. In vitro evaluation of insertion and removal torques of orthodontic mini-implants. Int J Oral Maxillofac Surg. International Association of Oral and Maxillofacial Surgery; 2011;40(1):80–5. [CrossRef ]
25. Pickard MB, Dechow P, Rossouw PE, Buschang PH. Effects of miniscrew orientation on implant stability and resistance to failure. Am J Orthod Dentofacial Orthop. American Association of Orthodontists; 2010;137(1):91–9.
26. Cho K-C, Baek S-H. Effects of predrilling depth and implant shape on the mechanical properties of orthodontic mini-implants during the insertion procedure. Angle Orthod. 2012;82(4):618– 24. [CrossRef ]
27. Wang C-H, Wu J-H, Lee K-T, Hsu K-R, Wang HC, Chen C-M. Mechanical strength of orthodontic infrazygomatic miniimplants. Odontology. 2011;99(1):98–100. [CrossRef ]
28. Lim S-A, Cha J-Y, Hwang C-J. Insertion torque of orthodontic miniscrews according to changes in shape, diameter and length. The Angle orthodontist. 2008;78(2):234-40. [CrossRef ]
29. Iijima M, Muguruma T, Brantley WA, Okayama M, Yuasa T, Mizoguchi I. Torsional properties and microstructures of miniscrew implants. Am J Orthod Dentofacial Orthop. 2008;134(3):333. [CrossRef ]