title: Influence of premolar extraction or non-extraction orthodontic therapy on the angular changes of mandibular third molars.
abstract: OBJECTIVE
  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.
  
  
  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'st-test.
  
  
  RESULTS
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Dental Health Department, Dental Biomaterials Research Chair, College of Applied Medical Sciences, King Saud University, Riyadh, Saudi Arabia.
authors.forename: Bangalore H
authors.initials: BH
authors.lastname: Durgesh
authors.affiliation: Department of Orthodontics, KVG Dental College and Hospital, Sullia, Karnataka, India.
authors.forename: Kiran H Komari
authors.initials: KH
authors.lastname: Gowda
authors.affiliation: Dental Health Department, Dental Biomaterials Research Chair, College of Applied Medical Sciences, King Saud University, Riyadh, Saudi Arabia.
authors.forename: Obaid A
authors.initials: OA
authors.lastname: AlShahrani
authors.affiliation: Ministry of Health and Al Farabi College for Medicine, Dentistry and Nursing, Saudi Arabia.
authors.forename: Ahmad D
authors.initials: AD
authors.lastname: Almalki
authors.affiliation: Ministry of Health and Al Farabi College for Medicine, Dentistry and Nursing, Saudi Arabia.
authors.forename: Waleed D
authors.initials: WD
authors.lastname: Almalki
authors.affiliation: Ministry of Health, North Health Sector of Riyadh, Saudi Arabia.
authors.forename: Manea Mohammed S
authors.initials: MM
authors.lastname: Balharith
authors.affiliation: Al Farabi College for Medicine, Dentistry and Nursing, Riyadh, Saudi Arabia.
authors.forename: Nada Yahya H
authors.initials: NY
authors.lastname: Motashesh
authors.affiliation: Dental Health Department, Dental Biomaterials Research Chair, College of Applied Medical Sciences, King Saud University, Riyadh, Saudi Arabia.
authors.forename: Abdulaziz A
authors.initials: AA
authors.lastname: Alkheraif
authors.affiliation: Dental Health Department, Dental Biomaterials Research Chair, College of Applied Medical Sciences, King Saud University, Riyadh, Saudi Arabia; Dental Biomaterials Department, College of Dentistry, Al Azhar University, Egypt.
authors.forename: Mohamed I
authors.initials: MI
authors.lastname: Hashem
keywords: Premolar extraction; Third molar angulation; Unerupted molar