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Factors associated with spontaneous angular changes of impacted mandibular third molars as a result of second molar protraction.
- Source :
-
American journal of orthodontics and dentofacial orthopedics : official publication of the American Association of Orthodontists, its constituent societies, and the American Board of Orthodontics [Am J Orthod Dentofacial Orthop] 2019 Aug; Vol. 156 (2), pp. 178-185. - Publication Year :
- 2019
-
Abstract
- Introduction: This study aimed to identify significant factors affecting the spontaneous angular changes of impacted mandibular third molars as a result of second molar protraction. Temporary skeletal anchorage devices in the missing mandibular first molar (ML-6) or missing deciduous mandibular second molar (ML-E) with missing succedaneous premolar spaces provided traction.<br />Methods: Forty-one mandibular third molars of 34 patients (10 male and 24 female; mean age 18.3 ± 3.7 years) that erupted after second molar protraction were included in this study. They were classified into upright (U) and tilted (T) groups. Linear and angular measurements were performed at the time of treatment initiation (T1) and of ML-6 or ML-E space closure (T2). Regression analyses were used to identify significant factors related to third molar uprighting.<br />Results: Nolla stage (odds ratio [OR] 4.1), sex (OR 0.003 for male), third molar angulation at T1 (OR 1.1), missing tooth space (OR 0.006), rate of third molar eruption (OR 23.3), and rate of second molar protraction (OR 0.2) significantly affected third molar uprighting. Age, third molar angulation at T1, rate of third molar eruption, and rate of second molar protraction were significant factors for predicting third molar angulation at T2.<br />Conclusions: Available space for third molar eruption before and after second molar protraction is not associated with uprighting of erupting third molars. Older patients whose third molars are in greater Nolla stage, are in a more upright position at T1, and have a greater eruption rate have a greater chance for third molar uprighting. Alternatively, an increase in second molar protraction rate results in mesial tipping of the third molars.<br /> (Copyright © 2019 American Association of Orthodontists. Published by Elsevier Inc. All rights reserved.)
- Subjects :
- Adolescent
Adult
Anatomic Landmarks
Bicuspid
Female
Humans
Male
Malocclusion diagnostic imaging
Mandible anatomy & histology
Mandible diagnostic imaging
Molar anatomy & histology
Molar diagnostic imaging
Molar physiopathology
Molar, Third anatomy & histology
Molar, Third diagnostic imaging
Orthodontic Appliances
Orthodontic Space Closure
Orthodontics, Corrective
Tooth Eruption
Tooth, Deciduous
Tooth, Impacted complications
Tooth, Impacted diagnostic imaging
Young Adult
Malocclusion physiopathology
Malocclusion prevention & control
Mandible physiopathology
Molar, Third physiopathology
Tooth, Impacted physiopathology
Subjects
Details
- Language :
- English
- ISSN :
- 1097-6752
- Volume :
- 156
- Issue :
- 2
- Database :
- MEDLINE
- Journal :
- American journal of orthodontics and dentofacial orthopedics : official publication of the American Association of Orthodontists, its constituent societies, and the American Board of Orthodontics
- Publication Type :
- Academic Journal
- Accession number :
- 31375227
- Full Text :
- https://doi.org/10.1016/j.ajodo.2018.08.024