The effects of alveolar bone loss and miniscrew position on initial tooth displacement during intrusion of the maxillary anterior teeth: Finite element analysis.
OBJECTIVE
The aim of this study was to determine the optimal loading conditions for pure intrusion of the six maxillary anterior teeth with miniscrews according to alveolar bone loss.


METHODS
A three-dimensional finite element model was created for a segment of the six anterior teeth, and the positions of the miniscrews and hooks were varied after setting the alveolar bone loss to 0, 2, or 4 mm. Under 100 g of intrusive force, initial displacement of the individual teeth in three directions and the degree of labial tilting were measured.


RESULTS
The degree of labial tilting increased with reduced alveolar bone height under the same load. When a miniscrew was inserted between the two central incisors, the amounts of medial-lateral and anterior-posterior displacement of the central incisor were significantly greater than in the other conditions. When the miniscrews were inserted distally to the canines and an intrusion force was applied distal to the lateral incisors, the degree of labial tilting and the amounts of displacement of the six anterior teeth were the lowest, and the maximum von Mises stress was distributed evenly across all the teeth, regardless of the bone loss.


CONCLUSIONS
Initial tooth displacement similar to pure intrusion of the six maxillary anterior teeth was induced when miniscrews were inserted distal to the maxillary canines and an intrusion force was applied distal to the lateral incisors. In this condition, the maximum von Mises stresses were relatively evenly distributed across all the teeth, regardless of the bone loss.
Private Practice, Namyangju, Korea.
Sun-Mi
SM
Cho
Department of Orthodontics, The Institute of Craniofacial Deformity, College of Dentistry, Yonsei University, Seoul, Korea.
Sung-Hwan
SH
Choi
Division of Orthodontics, Department of Dentistry, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
Sang-Jin
SJ
Sung
Department of Orthodontics, The Institute of Craniofacial Deformity, College of Dentistry, Yonsei University, Seoul, Korea.
Hyung-Seog
HS
Yu
Department of Orthodontics, The Institute of Craniofacial Deformity, College of Dentistry, Yonsei University, Seoul, Korea.
Chung-Ju
CJ
Hwang
Bone loss; Finite element analysis; Intrusion; Miniscrew
Niger J Clin Pract. 2011 Oct-Dec;14(4):449-53
22248948
J Dent Res. 2005 May;84(5):428-33
15840778
Am J Orthod Dentofacial Orthop. 2014 Jan;145(1):85-94
24373658
Eur J Orthod. 2009 Aug;31(4):412-6
19289539
Eur J Orthod. 1999 Dec;21(6):633-48
10665193
Am J Orthod Dentofacial Orthop. 1996 Sep;110(3):256-62
8814025
Korean J Orthod. 2015 Jan;45(1):20-8
25667914
Am J Orthod. 1976 Sep;70(3):241-68
786034
Korean J Orthod. 2014 Mar;44(2):54-61
24696821
Dent Clin North Am. 1999 Jan;43(1):37-44
9929798
Am J Orthod. 1977 Jul;72 (1):1-22
267433
Am J Orthod Dentofacial Orthop. 1993 Nov;104(5):448-54
8237897
Angle Orthod. 2007 Nov;77(6):999-1003
18004933
Am J Orthod Dentofacial Orthop. 1986 Oct;90(4):321-6
3464193
J Clin Orthod. 1997 Nov;31(11):763-7
9511584
Am J Orthod Dentofacial Orthop. 2011 Aug;140(2):224-32
21803260
Korean J Orthod. 2013 Feb;43(1):3-14
23502971
Eur J Orthod. 2007 Jun;29(3):219-24
17317864
J Periodontol. 1997 Oct;68(10):967-72
9358363
Am J Orthod. 1984 Apr;85(4):294-307
6585147
Am J Orthod Dentofacial Orthop. 2003 Apr;123(4):441-50
12695772
Am J Orthod Dentofacial Orthop. 1998 Dec;114(6):677-83
9844208
J Craniofac Surg. 2015 May;26(3):e240-4
25974822