The Effect of Force Application on the Stability of Mini-Screw in Different Insertion Angles (An in-vitro Study).


  • Lazha Latif Binyamen Department of Pedodontics, Orthodontics and Preventive Dentistry, College of Dentistry, Hawler Medical University, Erbil, Iraq.
  • Zana Qadir Omer Department of POP, College of Dentistry, Hawler Medical University, Erbil, Iraq.



Mini-screw, Stability, Insertion Angle, Shear force, Tensile force


Background and Objective: The stability of the mini-screw is an important factor for the success of orthodontic treatment using an absolute anchorage system. This study aims to evaluate
the ideal insertion angle of a mini-implant in relation to force direction and to evaluate the
maximum amount of force application at a specific angular configuration.
Method: In this experimental study 72 mini-screws were used, 36 of them were used for each
shear and tensile force tests, eighteen samples were taken for the bone density D2 (nine for 60ₒ
angle, and nine for 90ₒ
angle), and 18 others were taken for the bone density D3 (nine for 60ₒ angle, and nine for 90ₒ angle). Guiding stents were fabricated for proper insertion angle, torque and speed were controlled by contra -angled handpiece. Shear and tensile force tests are done with the aid of a Universal Testing Machine.
Results: Mini-implants inserted at 90̊ angle over D2 density bone had higher stability when performing the tensile force test, while in the shear force test mini-implants placed at 60̊ angle were more stable when inserted on bony blocks with D3 density, however it was noted that the results were statistically not significant when compared with 60̊ insertion on blocks with D2 density.
Conclusion: To maintain a stable mini-implant during the orthodontic process, the ideal insertion angle is 90̊ when the force direction is vertical, tensile force, and its more appropriate to place the mini-implant at 60̊ angle when the direction of force is in a horizontal direction, shear force.


Proffit WR, Fields HW, Larson B, Sarver DM. Contemporary orthodontics-e-book. Elsevier Health

Sciences; 2018, P 265.

Liu Y, Yang Z jin, Zhou J, Xiong P, Wang Q, Yang

Y, et al. Comparison of anchorage efficiency of

orthodontic mini-implant and conventional anchorage reinforcement in patients requiring

maximum orthodontic anchorage: a systematic

review and meta-analysis. Journal of Evidence

Based Dental Practice. 2020;20(2):101401.

Nienkemper M, Willmann JH, Drescher D. Longterm stability behavior of paramedian palatal

mini-implants: A repeated cross-sectional study.

American Journal of Orthodontics and Dentofacial Orthopedics. 2020;157(2):165–71.

Pan CY, Chou ST, Tseng YC, Yang YH, Wu CY, Lan

TH, et al. Influence of different implant materials on the primary stability of orthodontic miniimplants. The Kaohsiung Journal of Medical Sciences. 2012;28(12):673–8.

Scribante A, Montasser MA, Radwan ES, Bernardinelli L, Alcozer R, Gandini P, et al. Reliability

of orthodontic miniscrews: bending and maximum load of different Ti-6Al-4V titanium and

stainless steel temporary anchorage devices

(TADs). Materials. 2018;11(7):1138.

Sivamurthy G, Sundari S. Stress distribution

patterns at mini-implant site during retraction

and intrusion—a three-dimensional finite element study. Progress in orthodontics. 2016;17


Sakin Ç, Aylikci Ö. Techniques to measure miniscrew implant stability. Journal of Orthodontic

Research. 2013;1(1):5.

Manzano-Moreno FJ, Herrera-Briones FJ, Bassam T, Vallecillo-Capilla MF, Reyes-Botella C.

Factors affecting dental implant stability measured using the ostell mentor device: a systematic review. Implant dentistry. 2015;24(5):565–

Yao CCJ, Chang HH, Chang JZC, Lai HH, Lu SC,

Chen YJ. Revisiting the stability of mini-implants

used for orthodontic anchorage. Journal of the

Formosan Medical Association. 2015;114


Topouzelis N, Tsaousoglou P. Clinical factors

correlated with the success rate of miniscrews

in orthodontic treatment. International journal

of oral science. 2012;4(1):38–44.

Baumgaertel S. Hard and soft tissue considerations at mini-implant insertion sites. Journal of

Orthodontics. 2014;41(1_suppl):s3–7.

Al Amri MS, Sabban HM, Alsaggaf DH, Alsulaimani FF, Al-Turki GA, Al-Zahrani MS, et al. Anatomical consideration for optimal position of

orthodontic miniscrews in the maxilla: a CBCT

appraisal. Annals of Saudi Medicine. 2020;40


Brar LS, Dua VS. The magnitude and distribution pattern of stress on implant, teeth, and periodontium under different angulations of implant placement for en masse retraction: a finite

element analysis. Journal of Indian Orthodontic

Society. 2017;51(1):3–8.

Kniha K, Brandt M, Bock A, Modabber A,

Prescher A, Hölzle F, et al. Accuracy of fully guided orthodontic mini-implant placement evaluated by cone-beam computed tomography: A

study involving human cadaver heads. Clinical

Oral Investigations. 2021;25(3):1299–306.

Estelita S, Janson G, Chiqueto K, Garib D. Miniimplant insertion based on tooth crown references: a guide-free technique. International

journal of oral and maxillofacial surgery.


Janson G, Bombonatti R, Brandão AG, Henriques JFC, de Freitas MR. Comparative radiographic evaluation of the alveolar bone crest

after orthodontic treatment. American journal

of orthodontics and dentofacial orthopedics.


Nguyen MV, Codrington J, Fletcher L, Dreyer

CW, Sampson WJ. The influence of miniscrew

insertion torque. European journal of orthodontics. 2018;40(1):37–44.

Gurdán Z, Vajta L, Tóth Á, Lempel E, JoóbFancsaly Á, Szalma J. Effect of pre-drilling on

intraosseous temperature during self-drilling

mini-implant placement in a porcine mandible

model. Journal of oral science. 2017;59(1):47–

Melsen B, Costa A. Immediate loading of implants used for orthodontic anchorage. Clinical

orthodontics and research. 2000;3(1):23–8.

Çehreli S, Arman-Özçırpıcı A. Primary stability

and histomorphometric bone-implant contact of

self-drilling and self-tapping orthodontic microimplants. American journal of orthodontics

and dentofacial orthopedics. 2012;141(2):187–

Lin TS, Tsai FD, Chen CY, Lin LW. Factorial analysis of variables affecting bone stress adjacent to

the orthodontic anchorage mini-implant with

finite element analysis. American Journal of Orthodontics and Dentofacial Orthopedics.


Pan CY, Liu PH, Tseng YC, Chou ST, Wu CY,

Chang HP. Effects of cortical bone thickness and

trabecular bone density on primary stability of

orthodontic mini-implants. Journal of dental

sciences. 2019;14(4):383–8.

Araghbidikashani M, Golshah A, Nikkerdar N,

Rezaei M. In-vitro impact of insertion angle on

primary stability of miniscrews. American Journal of Orthodontics and Dentofacial Orthopedics. 2016;150(3):436–43.

Pickard MB, Dechow P, Rossouw PE, Buschang

PH. Effects of miniscrew orientation on implant

stability and resistance to failure. American Journal of Orthodontics and Dentofacial Orthopedics. 2010;137(1):91–9.

Watanabe F, Hata Y, Komatsu S, Ramos TC, Fukuda H. Finite element analysis of the influence

of implant inclination, loading position, and load

direction on stress distribution. Odontology.


Liou EJ, Pai BC, Lin JC. Do miniscrews remain

stationary under orthodontic forces? American

Journal of Orthodontics and Dentofacial Orthopedics. 2004;126(1):42–7.

da Cunha AC, Marquezan M, Lima I, Lopes RT,

Nojima LI, Sant’Anna EF. Influence of bone architecture on the primary stability of different miniimplant designs. American Journal of Orthodontics and Dentofacial Orthopedics. 2015;147(1):45


Möhlhenrich SC, Heussen N, Modabber A, Bock

A, Hölzle F, Wilmes B, et al. Influence of bone

density, screw size and surgical procedure on

orthodontic mini-implant placement–part B:

implant stability. International Journal of Oral

and Maxillofacial Surgery. 2021;50(4):565–72.

uja SS, Litsky AS, Beck FM, Johnson KA, Larsen

PE. Pull-out strength of monocortical screws

placed in the maxillae and mandibles of dogs.

American journal of orthodontics and dentofacial orthopedics. 2005;127(3):307–13.




How to Cite

Binyamen LL, Omer ZQ. The Effect of Force Application on the Stability of Mini-Screw in Different Insertion Angles (An in-vitro Study). EDJ [Internet]. 2023 Dec. 22 [cited 2024 Mar. 5];6(2):175-82. Available from:



Original Articles