Effects of first premolar extraction on maxillary and mandibular third molar angulation after orthodontic therapy.
OBJECTIVE
To compare the change in the angulation of developing mandibular third molar in both first premolar extraction and non-extraction cases and to determine whether premolar extraction results in a more mesial movement of the mandibular buccal segment and causes favorable rotational changes in the mandibular third molar tilt, which can enhance later eruption of the third molars.


METHODS
Pretreatment (T1) and post treatment (T2) panoramic radiographs were taken of 25 subjects (age 14-19 years) who had been treated by the extraction of all the first premolars and 25 subjects who had been treated with non-extraction. The horizontal reference plane was used to measure and compare the changes in the angles of the developing mandibular third molars.


RESULTS
The mean uprighting of the maxillary third molars seen in the extraction group was 4 ± 9° on the left side and -17 ± 13° on the right side following treatment (T2 _ T1). For the non-extraction group the mean difference was -16 ± 12° on the left side and 2 ± 13° on the right side. There was a statistically significant difference between the groups (P _ 0.021 on the right side and P _ 0.041 on the left side). Mandibular 3rd molars in extraction group showed no statistical significant change in the angulation.


CONCLUSIONS
Premolar extractions had a positive influence on the developing maxillary third molar angulations both on right and left. Mandibular 3rd molar have shown change in the angulation but not statistically significant. Non-extraction therapy did not have any adverse effect.
Postgraduate Student, Department of Orthodontics, KLE V.K. Institute of Dental Sciences, JNMC campus, Nehru Nagar, Belgaum 590010, Karnataka, India.
Avinash
A
Gohilot
Professor, Department of Orthodontics, KLE V.K. Institute of Dental Sciences, JNMC campus, Nehru Nagar, Belgaum 590010, Karnataka, India.
Tejashri
T
Pradhan
Professor and Head of the Department, Department of Orthodontics, KLE V.K. Institute of Dental Sciences, JNMC campus, Nehru Nagar, Belgaum 590010, Karnataka, India.
Kanhoba Mahabaleshwar
KM
Keluskar
OPG; Premolar extractions; Third molar angulations