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Title No Significant Difference in Relapse of Anterior Crowding in Class I and Class II Malocclusions Treated with or without Premolar Extractions and Retained with Hawley Retainers
Clinical Question In healthy patients with Angle Class I or Class II malocclusions, does orthodontic treatment with premolar extraction’s provide better long-term stability of anterior crowding compared to non-extraction orthodontic treatment?
Clinical Bottom Line Although there was a small amount of post-treatment increase in incisor irregularity in both groups, there were no significant differences between the extraction and non-extraction cases. The quality of the finish and method of retention may be variables that affect stability.
Best Evidence (you may view more info by clicking on the PubMed ID link)
PubMed ID Author / Year Patient Group Study type
(level of evidence)
#1) 16769496 Erdinc/2006Adolescent patients (n =98) equally divided into extraction group (n=49) and nonextraction group (n=49).Retrospective Cohort Study
Key resultsErdinc et al. (2006) reported that there were no significant differences in long-term stability between extraction and non-extraction groups. Both groups had stable maxillary alignment. Mandibular incisor irregularity increased 0.97 mm in the extraction group and 0.99 mm in the non-extraction group. Inter-canine width was expanded during treatment, and decreased in both groups at T3, but the differences were not statistically significant. With the exception of the inter-incisal angle, no statistically significant differences were recorded between the extraction and non-extraction groups from T2 to T3.
#2) 21640883Quaglio/201170 patients with Class I and II Division 1 malocclusion and at least 3mm of crowding on Little’s irregularity index in Mandible (LllMx) divided in three groups (n1=30, n2=20, n3=20).Retrospective Cohort study
Key resultsQuaglio et al. examined the stability of alignment of the maxillary anterior teeth between class I and class II malocclusions treated with premolar extractions. No statistically significant differences were evident in the long-term stability of the alignment of the maxillary anterior teeth between Class I and Class II malocclusions. Stability of maxillary anterior alignment ranged from 86 to 91 %. A statistically significant positive correlation between crowding at T2 and T3 (R = .4380 at P = .000) indicated the importance of good alignment at T2.
Evidence Search Premolar OR bicuspid [MeSH Terms] AND extraction AND crowding AND relapse [MeSH Terms]
Comments on
The Evidence
Erdinc et al. conducted a retrospective cohort study of various predictors of post-treatment mandibular incisor relapse. Measurement method reliability was established using the paired t-test on 20 randomly selected models and cephalograms. The mean post-retention time was 4 years 11months. The Quaglio study evaluated patients at least 5 years after treatment. Both studies used Hawley retainers. Relapse is most common in the mandibular incisor region, and thus retention with a mandibular fixed retainer may have provided differing results. The quality of the finished result may also have an effect on the stability of the alignment; however, neither study alluded to any objective grading of the finish.
Applicability These results are applicable to adolescent class I and Class II Division I patients treated with or without extractions.
Specialty/Discipline (Orthodontics)
Keywords Anterior crowding, premolars, extraction
ID# 2706
Date of submission: 04/09/2014spacer
E-mail Linhduong@livemail.uthscsa.edu
Author Mylinh Duong
Co-author(s) e-mail
Faculty mentor/Co-author Peter T. Gakunga, BDS, MS, PhD
Faculty mentor/Co-author e-mail GAKUNGA@uthscsa.edu
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