title: Radiographic assessment of lower third molar eruption in different anteroposterior skeletal patterns and age-related groups.
abstract: OBJECTIVE
  To analyze radiographic predictors for lower third molar eruption among subjects with different anteroposterior skeletal relations and of different age groups.
  
  
  METHODS
  In total, 300 lower third molars were recorded on diagnostic digital orthopantomograms (DPTs) and lateral cephalograms (LCs). The radiographs were grouped according to sagittal intermaxillary angle (ANB), subject age, and level of lower third molar eruption. The DPT was used to analyze retromolar space, mesiodistal crown width, space/width ratio, third and second molar angulation (α, γ), third molar inclination (β), and gonion angle. The LC was used to determine ANB, angles of maxillar and mandibular prognathism (SNA, SNB), mandibular plane angle (SN/MP), and mandibular lengths. A logistic regression model was created using the statistically significant predictors.
  
  
  RESULTS
  The logistic regression analysis revealed a statistically significant impact of β angle and distance between gonion and gnathion (Go-Gn) on the level of lower third molar eruption (P < .001 and P < .015, respectively). The retromolar space was significantly increased in the adult subgroup for all skeletal classes. The lower third molar impaction rate was significantly higher in the adult subgroup with the Class II (62.3%) compared with Class III subjects (31.7%; P < .013).
  
  
  CONCLUSIONS
  The most favorable values of linear and angular predictors of mandibular third molar eruption were measured in Class III subjects. For valid estimation of mandibular third molar eruption, certain linear and angular measures (β angle, Go-Gn), as well as the size of the retromolar space, need to be considered.
authors.affiliation: a  PhD student, Department of Oral Surgery and Implantology, School of Dental Medicine, University of Belgrade, Belgrade, Serbia.
authors.forename: Aleksandar
authors.initials: A
authors.lastname: Jakovljevic
authors.affiliation: b  PhD student, Department of Orthodontics, School of Dental Medicine, University of Belgrade, Belgrade, Serbia.
authors.forename: Emira
authors.initials: E
authors.lastname: Lazic
authors.affiliation: c  Assistant, Institute of Medical Statistics and Informatics, Faculty of Medicine, University of Belgrade, Belgrade, Serbia.
authors.forename: Ivan
authors.initials: I
authors.lastname: Soldatovic
authors.affiliation: d  Assistant Professor, Department of Orthodontics, School of Dental Medicine, University of Belgrade, Belgrade, Serbia.
authors.forename: Nenad
authors.initials: N
authors.lastname: Nedeljkovic
authors.affiliation: e  Assistant Professor, Department of Oral Surgery and Implantology, School of Dental Medicine, University of Belgrade, Belgrade, Serbia.
authors.forename: Miroslav
authors.initials: M
authors.lastname: Andric
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D002508:Cephalometry / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008310:Malocclusion / Q000000981:diagnostic imaging*; D008312:Malocclusion, Angle Class II / Q000000981:diagnostic imaging; D008313:Malocclusion, Angle Class III / Q000000981:diagnostic imaging; D008334:Mandible / Q000000981:diagnostic imaging*; D008437:Maxilla / Q000000981:diagnostic imaging; D008963:Molar / Q000000981:diagnostic imaging; D008964:Molar, Third / Q000000981:diagnostic imaging* / Q000502:physiology; D009295:Nasal Bone / Q000000981:diagnostic imaging; D011378:Prognathism / Q000000981:diagnostic imaging; D019252:Radiography, Dental, Digital / Q000379:methods*; D011862:Radiography, Panoramic / Q000379:methods*; D019228:Tooth Crown / Q000000981:diagnostic imaging; D014078:Tooth Eruption / Q000502:physiology*; D014095:Tooth, Impacted / Q000000981:diagnostic imaging; D055815:Young Adult
keywords: Impaction; Lower third molar; Radiographic predictors