Influence of premolar extraction or non-extraction orthodontic therapy on the angular changes of mandibular third molars

Obaid A. AlShahrani

Bangalore H. Durgesh

Abdulaziz A. Alkheraif

Waleed D. Almalki

Kiran H. Komari Gowda

Manea Mohammed S. Balharith

Ahmad D. Almalki

Mohamed I. Hashem

Nada Yahya H. Motashesh

Lataukset:

Abstract Aim: To compare the angular changes of the third molars relative to the occlusal plane

and to the second molar long axis in extraction group and compare these changes with a non extraction

group.

Materials and methods: The study included pre and post treatment panoramic radiograph

records of 90 subjects treated by first premolar extractions and 90 subjects who had been treated

with non extraction orthodontic therapy (n=90). Two angular variables were measured. Firstly,

the angle between the long axis of the third molar and the occlusal plane (M3–OP) and secondly,

the angle between the long axis of the third molar and the long axis of the second molar (M3–M2).

Data were analyzed by paired and student’s t-test.

Result: The analyzed data to assess the changes in the third molar angulation from pretreatment

to post treatment did not vary significantly in both the groups (p<0.05). Both the groups showed

decreased angular values. The M3–OP angular difference was (7.3± 2.45) in extraction group as

compared to (5.85 ± 1.77) in non extraction group. The M3–M2 angular difference of (4.26

±3.11) in extraction group and (2.98 ±1.74) in non-extraction group was observed

Conclusion: Extraction of premolars did not demonstrate considerable changes on the angulation

of the third molars. The factors other than premolar extractions may influence the angulation

of the third molars.