3D Evaluation of Lower Second Molar Movement into the First Molar Site Using a Bicortical Mini-implant with Two Anchorage Heads
Abdeen Shaker¹, Yasser Rsheadat¹, M. Bashar Muselmani², Stefan Kopp³ — ¹ University of Aleppo, Aleppo, Syria; ² Tishreen University, Latakia, Syria; ³ University Hospital, Frankfurt am Main, Germany
Poster P55
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2012
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85. Wissenschaftliche Jahrestagung der DGKFO, Stuttgart 2012
Introduction
The permanent first molar is the tooth most frequently lost due to caries or periodontal disease. Orthodontic molar protraction may be a favorable alternative to dental implants or prostheses. Temporary anchorage devices (TADs) can provide stable and reliable anchorage. Bicortical miniscrews offer superior anchorage resistance, reduced cortical bone stress, and greater stability compared with monocortical screws.
Purpose
This study aimed to evaluate a new technique for protracting the lower second molar into the first molar site.
Methods
Eleven patients were selected: four with bilateral absence of the lower first molars and seven with unilateral absence of a lower first molar. The selection criteria included age between 13 and 17 years, presence of the third molar, and no indication for retraction of the lower anterior teeth. A CBCT image was obtained for each patient before treatment, and a special guide was fabricated to insert a bicortical screw with two anchorage heads between the lower premolar roots. Bands with two cantilever arms were placed and welded buccally and lingually at the level of the center of resistance of the lower second molar. A 60 g orthodontic force was applied using an elastic chain or a NiTi coil spring between the screw heads and the cantilever arms. A CBCT image was obtained again at the end of each patient's treatment.
Results
Computer software was used to perform a 3D evaluation of the final movement of the lower second molar.
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