Comparison of Changes in Mandibular Third Molar Angulation Following First/Second Premolar Extraction versus Non-Extraction Orthodontic Treatments
Journal of Dental School,
Vol. 31 No. 2 (2013),
27 April 2013
,
Page 87-94
https://doi.org/10.22037/jds.v31i2.29089
Abstract
Objective: Extraction of premolars is believed to affect the eruption of third molars. This comparative study aimed to assess the change in angulation of third molars following first/second premolar extraction versus non-extraction orthodontic treatments.
Methods: This historical cohort study was conducted on patients assigned to three treatment groups: extraction of mandibular first premolars (group A), extraction of mandibular second premolars (group B) and non-extraction orthodontic treatment (group C). Each group included 30 third molars. Patients were in the age range of 11-19 years and the third molars were in Nolla’s6-8 stage of tooth development. Pre- and post-treatment panoramic radiographs were analyzed.
Results: The angle between the long axis of the mandibular third molar and mandibular plane increased by 7 (2.2°) in group A and 5.2° in group B and the increase in both groups was statistically significant (p<0.05). Angular changes in group C were not statistically significant (p>0.05). The angle between the long axes of mandibular first and third molars decreased by 6.83 (0.3°) in group A. This reduction was statistically significant (p<0.05).
Conclusion: In extraction orthodontic treatments (versus non-extraction treatments), mandibular third molars tend to straighten up and become upright so the risk of their impaction may be decreased.
- Mandible
- Orthodontics
- Premolar
- Third molar
- Tooth angulation
- Tooth extraction
How to Cite
References
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