The effect of maxillary first premolar extraction and incisor retraction on mandibular position: Testing the central dogma of “functional orthodontics”

Author(s):  
Percy E. Luecke ◽  
Lysie E. Johnston
2012 ◽  
Vol 83 (4) ◽  
pp. 680-685 ◽  
Author(s):  
Min-Ho Jung

ABSTRACT Objective: The effect of total arch distalization using orthodontic mini-implants (OMIs) combined with interproximal stripping (IPS) and second premolar extraction was investigated in Class I malocclusion patients. Materials and Methods: A total of 66 consecutively treated Class I malocclusion (Class I molar relationship; 0 mm < overbite and overjet < 4.5 mm) patients ranging in age from 17 to 44 years who received single-phase treatment were included in this study. Pre- and posttreatment lateral cephalograms and dental casts were measured and compared statistically. Results: In the distalization with IPS group, 3.6 mm and 3.8 mm of crowding in the upper and lower arches, respectively, were resolved, and 3.8 mm and 3.2 mm of upper and lower incisor retraction, respectively, were achieved simultaneously by the treatment. As a result of the second premolar extraction treatment, 3.9 mm and 3.6 mm of crowding in the upper and lower arches, respectively, were resolved, and 3.3 mm and 3.2 mm of incisor retraction, respectively, were achieved during treatment. There was no statistically significant difference in the amount of crowding and incisor retraction between the two groups. Conclusions: Total arch distalization using an OMI with IPS did not yield a significantly different treatment result compared to second premolar extraction treatment.


2019 ◽  
Vol 89 (5) ◽  
pp. 679-687 ◽  
Author(s):  
Fan-Fan Dai ◽  
Tian-Min Xu ◽  
Guang Shu

ABSTRACT Objectives: To compare achieved and predicted tooth movements of maxillary first molars and central incisors in first premolar extraction cases treated with Invisalign. Materials and Methods: The present study included 30 patients who received maxillary first premolar extraction treatment with Invisalign. The actual posttreatment model was registered with the pretreatment model on the palatal stable region and superimposed with the virtual posttreatment model. Achieved and predicted tooth movements of maxillary first molars and central incisors were compared using paired t-test. Linear mixed-effect model analyses were used to explore the influence of age (adolescents vs adults), attachment (G6-optimized vs 3-mm vertical, 3-mm horizontal, and 5-mm horizontal), and initial crowding on the differences between predicted and achieved tooth movement (DPATM). Results: First molars achieved greater mesial tipping, mesial translation, and intrusion than predicted. Central incisors achieved less retraction and greater lingual crown torque and extrusion than predicted. Adolescents showed greater DPATM in the mesiodistal translation of first molars and labiolingual translation of central incisors and smaller DPATM in the occlusogingival translation of the first molars and crown torque of the central incisors than adults. The 3-mm vertical attachment group showed greater DPATM in the mesiodistal translation of the first molars vs the G6-optimized attachment group. Initial crowding had an inverse correlation with DPATM in angulation and mesiodistal translation of the first molars. Conclusions: First molar anchorage control and central incisor retraction were not fully achieved as predicted in first premolar extraction treatment with Invisalign. Age, attachment, and initial crowding affected the differences between predicted and achieved tooth movement.


2021 ◽  
Vol 17 (1) ◽  
Author(s):  
Qiannan Sun ◽  
Wenhsuan Lu ◽  
Yunfan Zhang ◽  
Liying Peng ◽  
Si Chen ◽  
...  

Abstract Backgroud To analyze the morphological changes of the anterior alveolar bone after the retraction of incisors in premolar extraction cases and the relationship between incisor retraction and remodeling of the alveolar base represented by points A and B displacements. Methods Pre- (T0) and post-treatment (T1) lateral cephalograms of 308 subjects in the maxilla and 154 subjects in the mandible who underwent the orthodontic treatment with extraction of 2 premolars in upper or lower arches were included. Alveolar bone width and height in both the maxillary and mandible incisor area were measured at T0 and T1 respectively. By superimposing the T0 and T1 cephalometric tracings, changes of points A and B, and the movement of the incisors were also measured. Then the correlation between incisor movement and the displacements of points A and B was analyzed. Results The alveolar bone width (ABW) showed a significant decrease in both maxilla and mandible (P < 0.001) except the labial side of the mandible (P > 0.05). The alveolar bone height (ABH) showed a significant increase in the labial side of maxilla and a significant decrease in the lingual side of maxilla and mandible. A strong positive correlation was verified between incisor movement and position changes of points A and B in both horizontal and vertical directions. Conclusions Anterior alveolar bone width and height generally decreased after orthodontic treatment. Incisor retraction led to significant position changes of points A and B. The decrease of anterior alveolar bone due to significant incisor retraction should be taken into account in treatment planning.


Neuron ◽  
2013 ◽  
Vol 80 (3) ◽  
pp. 648-657 ◽  
Author(s):  
Christine E. Holt ◽  
Erin M. Schuman

2016 ◽  
pp. 25-31
Author(s):  
David S. Goodsell
Keyword(s):  

1996 ◽  
Vol 17 (1) ◽  
pp. 48-52
Author(s):  
Kazuhiko Chiba ◽  
Yutaka Matsuda ◽  
Hiroyasu Sugano
Keyword(s):  

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