Table of Contents
ISRN Dentistry
Volume 2011, Article ID 321206, 7 pages
Research Article

Comparison of Movement of the Upper Dentition According to Anchorage Method: Orthodontic Mini-Implant versus Conventional Anchorage Reinforcement in Class I Malocclusion

Department of Orthodontics, The Institute of Oral Health Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, No. 50, Irwon-dong, Gangnam-Gu, Seoul 135-710, Republic of Korea

Received 16 October 2010; Accepted 7 November 2010

Academic Editors: C.-A. Trotman and G. Janson

Copyright Β© 2011 Ah-Young Lee and Young Ho Kim. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Objective. To compare the amounts of anchorage loss in the upper first molar (U6) and of retraction of the upper central incisor (U1) in cases with Class I malocclusion between orthodontic mini-implants (OMIs) and conventional anchorage reinforcements (CARs). Methods. The subjects were 40 female adult patients with Class I malocclusion who were treated with extraction of the first premolars and sliding mechanics. The subjects were divided into Groups 1 ( 𝑁 = 2 0 , CAR) and 2 ( 𝑁 = 2 0 , OMI) according to anchorage method. Lateral cephalograms were taken before (T0) and after treatment (T1). Seven skeletal and dental variables and ten anchorage variables were measured. Mann-Whitney test was used for statistical analysis. Results. Group 2 showed significantly larger retraction of U1 (U1E-sag, 9.5 mm : 7.1 mm, 𝑃 < . 0 5 ) and less anchorage loss of U6 (U6M-sag, 0.2 mm : 2.2 mm, 𝑃 < . 0 5 ; U6A-sag, 0.3 mm versus 2.4 mm, 𝑃 < . 0 1 ) than Group 1. There was opposite vertical movement in U1 and U6 between Groups 1 and 2 (U1E-ver, 0.9 mm intrusion : 0.7 mm extrusion; U6F-ver, 1.0 mm intrusion : 0.9 mm extrusion, 𝑃 < . 0 5 ). Conclusion. Although OMI could not reduce the treatment duration, it could provide better maximum anchorage of U6, greater retraction of U1, intrusion of U1 and U6 than CAR.