Influence of geometric design characteristics on primary stability of orthodontic miniscrews

  • Eman Saad Radwan
  • Mona A MontasserEmail author
  • Ahmed Maher
Original Article



Aim of the present study was to investigate the influence of geometric design characteristics on primary stability of orthodontic miniscrews.

Materials and methods

Forty self-drilling miniscrews with different geometric design characteristics were divided into the following groups (n = 10): group I—Tomas® (Dentaurum, Germany), group II—AbsoAnchor® (Dentos, Korea), group III—HUBIT® miniscrew (HUBIT, Korea), group IV—Creative® (China). The four types were conical miniscrews with 1.6 mm diameter and 6.0 mm length. The miniscrews were manually inserted perpendicular to cow ribs until the full thread length was reached with the help of a 1.3 mm predrilled pilot hole. Each miniscrew was evaluated using scanning electron microscope. Linear and angular measurements were taken using Photoshop CS3 software. Miniscrew stability was measured by the Periotest® and pullout test.


All linear and angular measurements of the geometric characteristics showed significant differences between the four groups (p ≤ 0.001). Results of the pullout test showed significant differences between the four groups (p ≤ 0.001), while the Periotest® values showed no significant differences (p = 0.122). A multiple linear regression analysis revealed the significant predictors for higher pullout: a larger flank, a higher value for the thread angle, lead angle, and apical face angle (p ≤ 0.001).


Orthodontic miniscrews’ geometric design characteristics significantly affected the primary stability. Larger pitch width, flank, thread angle, apical face angle, and/or lead angle led to higher primary stability. Smaller a thread shape factor (TSF) also improved primary stability. Varying these characteristics may enhance miniscrew design.


Miniscrews Geometric design Primary stability Skeletal anchorage  Pullout test 

Einfluss des geometrischen Designs auf die Primärstabilität von kieferorthopädischen Minischrauben



In der vorliegenden Studie wurde der Einfluss geometrischer Merkmale auf die Primärstabilität von kieferorthopädischen Minischrauben untersucht.

Material und Methoden

Vierzig selbstbohrende Minischrauben mit unterschiedlichem geometrischen Design von 4 Herstellern wurden in Gruppen (n = 10) eingeteilt: Gruppe I: Tomas® (Dentaurum, Germany), Gruppe II: AbsoAnchor® (Dentos, Korea), Gruppe III: HUBIT® (HUBIT, Korea) und Gruppe IV: Creative® (China). Bei den vier Typen handelte es sich um konische Minischrauben von 1,6 mm Durchmesser und 6 mm Länge. Nach Setzen der Pilotbohrung (Durchmesser: 1,3 mm) wurden die Minischrauben manuell senkrecht in bovine Rippen vollständig inseriert. Jede Schraube wurde elektronenmikroskopisch untersucht und unter Verwendung der Software Photoshop CS3 vermessen. Die Primärstabilität wurde mittels Periotest® und Pullout-Test überprüft.


Zwischen den 4 Gruppen zeigten sich bezüglich aller geometrischen Merkmale statistisch signifikante Unterschiede (p ≤ 0,001). Statistisch signifikante Unterschiede zeigten sich ebenfalls für die Ergebnisse des Pullout-Tests (p ≤ 0,001), jedoch nicht für die Periotest® Werte (p = 0,122). Die multiple lineare Regressionsanalyse ergab als wesentliche Prädiktoren für erhöhte Pullout-Werte: vergrößerte(r) Flanke/Flankensteigung, Gewindesteigung und Scheitelwinkel (p ≤ 0,001).


Bestimmte Merkmale des Schraubendesigns beeinflussten die Primärstabilität kieferorthopädischer Minischrauben signifikant. Vergrößerte(r) Gewindeschneidenabstand, Flanke/Flankensteigung, Gewindesteigung und Scheitelwinkel bedingten eine höhere Primärstabilität. Auch ein verkleinerter Gewindefaktor (TSF) verbesserte die Primärstabilität. Durch Variieren dieser Merkmale lässt sich das Minischraubendesign weiter optimieren.


Minischrauben Geometrisches Design Primärstabilität Skelettale Verankerung Pullout-Test 


Conflict of interest

E.S. Radwan, M.A. Montasser and A. Maher declare that they have no competing interests.


  1. 1.
    Brinley CL, Behrents R, Kim KB, Condoor S, Kyung HM, Buschang PH (2009) Pitch and longitudinal fluting effects on the primary stability of miniscrew implants. Angle Orthod 79:1156–1161CrossRefPubMedGoogle Scholar
  2. 2.
    Chang JZ, Chen YJ, Tung YY, Chiang YY, Lai EH, Chen WP et al (2012) Effects of thread depth, taper shape, and taper length on the mechanical properties of mini-implants. Am J Orthod Dentofacial Orthop 141:279–288CrossRefPubMedGoogle Scholar
  3. 3.
    Choi JH, Park CH, Yi SW, Lim HJ, Hwang HS (2009) Bone density measurement in interdental areas with simulated placement of orthodontic miniscrew implants. Am J Orthod Dentofacial Orthop 136:766.e1–766.e12Google Scholar
  4. 4.
    Cunha AC, Freitas AO, Marquezan M, Nojima LI (2015) Mechanical influence of thread pitch on orthodontic mini-implant stability. Braz Oral Res 29:1–6CrossRefGoogle Scholar
  5. 5.
    Chapman JR, Harrington R, Lee K, Anderson P, Tencer AF, Kowalski D (1996) Factors affecting the pullout strength of cancellous bone screws. J Biomech Eng 118:391–398CrossRefPubMedGoogle Scholar
  6. 6.
    da Cunha AC, Marquezan M, Lima I, Lopes RT, Nojima LI, Sant’Anna EF (2015) Influence of bone architecture on the primary stability of different mini-implant designs. Am J Orthod Dentofacial Orthop 147:45–51CrossRefPubMedGoogle Scholar
  7. 7.
    Diefenbeck M, Mückley T, Zankovych S, Bossert J, Jandt KD, Schrader C, Schmidt J, Finger U, Faucon M (2011) Freezing of rat tibiae at -20°C does not affect the mechanical properties of intramedullary bone/implant-interface: brief report. Open Orthop J 5:219–222CrossRefPubMedPubMedCentralGoogle Scholar
  8. 8.
    Huja SS, Litsky AS, Beck FM, Johnson KA, Larsen PE (2005) Pull-out strength of monocortical screws placed in the maxillae and mandibles of dogs. Am J Orthod Dentofacial Orthop 127:307–313CrossRefPubMedGoogle Scholar
  9. 9.
    Katić V, Kamenar E, Blažević D, Špalj S (2014) Geometrical design characteristics of orthodontic mini-implants predicting maximum insertion torque. Korean J Orthod 44:177–183CrossRefPubMedPubMedCentralGoogle Scholar
  10. 10.
    Kitahara-Céia FMF, Assad-Loss TF, Mucha JN, Elias CN (2013) Morphological evaluation of the active tip of six types of orthodontic mini-implants. Dental Press J Orthod 18:36–41CrossRefPubMedGoogle Scholar
  11. 11.
    Motoyoshi M, Yoshida T, Ono A, Shimizu N (2007) Effect of cortical bone thickness and implant placement torque on stability of orthodontic mini-implants. Int J Oral Maxillofac Surg 22:779–784Google Scholar
  12. 12.
    Migliorati M, Benedicenti S, Signori A, Drago S, Barberis F, Tournier H et al (2012) Miniscrew design and bone characteristics: an experimental study of primary stability. Am J Orthod Dentofacial Orthop 142:228–234CrossRefPubMedGoogle Scholar
  13. 13.
    Migliorati M, Signori A, Biavati AS (2012) Temporary anchorage device stability: an evaluation of thread shape factor. Eur J Orthod 34:582–586CrossRefPubMedGoogle Scholar
  14. 14.
    Migliorati M, Benedicenti S, Signori A, Drago S, Cirillo P, Barberis F et al (2013) Thread shape factor: evaluation of three different orthodontic miniscrews stability. Eur J Orthod 35:401–405CrossRefPubMedGoogle Scholar
  15. 15.
    Ozawa T, Takahashi K, Yamagata M, Ohtori S, Aoki Y, Saito T et al (2005) Insertional torque of the lumbar pedicle screw during surgery. J Orthop Sci 10:133–136CrossRefPubMedGoogle Scholar
  16. 16.
    Park JC, Lee JH, Lee JW, Kim SM (2011) Implant stability-measuring devices and randomized clinical trial for ISQ value change pattern measured from two different directions by magnetic RFA. In: Implant Dentistry TI (ed) A rapidly evolving practice. In Tech, Korea, pp 112–128 (Available from Scholar
  17. 17.
    Pithon M, Nojima M, Nojima L (2011) In vitro evaluation of insertion and removal torques of orthodontic mini-implants. Int J Oral Maxillofac Surg 40:80–85CrossRefPubMedGoogle Scholar
  18. 18.
    Rosa RC, Silva P, Shimano AC, Volpon JB, Defino HL, Schleicher P et al (2008) Biomechanical analysis of the variables related to the pullout strength of screws in the vertebral fixation system. Rev Bras Ortop 43:293–299CrossRefGoogle Scholar
  19. 19.
    Silvestrini Biavati A, Tecco S, Migliorati M, Festa F, Marzo G, Gherlone E et al (2011) Three‐dimensional tomographic mapping related to primary stability and structural miniscrew characteristics. Orthod Craniofac Res 14:88–99CrossRefPubMedGoogle Scholar
  20. 20.
    Steigenga JT, Al-Shammari KF, Nociti FH, Misch CE, Wang HL (2003) Dental implant design and its relationship to long-term implant success. Implant Dent 12:306–317CrossRefPubMedGoogle Scholar
  21. 21.
    Su YY, Wilmes B, Hönscheid R, Drescher D (2009) Application of a wireless resonance frequency transducer to assess primary stability of orthodontic mini-implants: an in vitro study in pig ilia. Int J Oral Maxillofac Implants 24:647–654PubMedGoogle Scholar
  22. 22.
    Tsai WC, Chen PQ, Lu TW, Wu SS, Shih KS, Lin SC (2009) Comparison and prediction of pullout strength of conical and cylindrical pedicle screws within synthetic bone. BMC Musculoskelet Disord 10:1–9CrossRefGoogle Scholar
  23. 23.
    Wilmes B, Rademacher C, Olthoff G, Drescher D (2006) Parameters affecting primary stability of orthodontic mini-implants. J Orofac Orthop 67:162–174CrossRefPubMedGoogle Scholar
  24. 24.
    Wilmes B, Su YY, Sadigh L, Drescher D (2008) Pre-drilling force and insertion torques during orthodontic mini-implant insertion in relation to root contact. J Orofac Orthop 69:51–58CrossRefPubMedGoogle Scholar
  25. 25.
    Cope JB (2005) Temporary anchorage devices in orthodontics: a paradigm shift. Seminars in Orthodontics 11:3–9Google Scholar
  26. 26.
    Zix J, Hug S, Kessler-Liechti G, Mericske-Stern R (2008) Measurement of dental implant stability by resonance frequency analysis and damping capacity assessment: comparison of both techniques in a clinical trial. Int J Oral Maxillofac Surg 23:525–530Google Scholar
  27. 27.
    Zamarioli A, Simões PA, Shimano AC, Defino HL (2008) Insertion torque and pullout strength of vertebral screws with cylindrical and conical core. Rev Bras Ortop 43:452–459CrossRefGoogle Scholar

Copyright information

© Springer Medizin Verlag GmbH, ein Teil von Springer Nature 2018

Authors and Affiliations

  • Eman Saad Radwan
    • 1
  • Mona A Montasser
    • 1
    Email author
  • Ahmed Maher
    • 1
  1. 1.Orthodontic Department, Faculty of DentistryMansoura UniversityMansouraEgypt

Personalised recommendations