title: Evaluation of the position of unerupted mandibular third molars with and without root dilacerations: a study on panoramic radiographs.
abstract: BACKGROUND
  Factors that can directly influence the extraction of third molars include the position of the tooth and the presence of root dilacerations. Knowledge of these features favors an accurate therapeutic evaluation of third molars; therefore, the aim of this study was to evaluate, using panoramic radiographs, the positioning of unerupted third molars with and without root dilacerations and to verify a possible association between these two variables.
  
  
  METHODS
  In this study, 16,136 panoramic radiographs were analyzed, including 1756 lower third molars, in which the positioning was assessed according to the Winter classification and the presence of root dilacerations was determined. The data obtained from the assessments of the frequencies of the positions and the presence of root dilacerations of impacted mandibular third molar was described. A χ2 test was applied to verify a possible association between the variables.
  
  
  RESULTS
  The results indicated that the most frequent position was mesioangular (44.5%), followed by horizontal (24.9%), vertical (17.4%), distoangular (12.5%), inverted (0.4%), and linguoangular (0.3%). Of the mandibular third molars evaluated, 35% had root dilacerations. The chi-square test revealed a significant association between the position of the tooth and the presence of root dilacerations (P<0.0001, χ2=34.28). The frequency of root dilaceration was statistically higher for the vertical (45.5%) and distoangular positions (40.9%).
  
  
  CONCLUSIONS
  The mesioangular position was the most prevalent location for lower third molars, and the highest frequencies of root dilacerations were observed in the vertical and distoangular positions. Knowledge about the prevalence of root dilacerations and the significant association between the position of the third molars and root dilacerations will allow safer surgical planning for dental extractions of third molars.
authors: School of Dentistry, State University of Piracicaba, Piracicaba, Brazil - karina.devito@ufjf.edu.br.
authors: Mariana R
authors: MR
authors: Nadaes
authors: Caroline P
authors: CP
authors: Maues
authors: Carolina O
authors: CO
authors: DE Andrade
authors: Luciana A
authors: LA
authors: Salvio
authors: Karina L
authors: KL
authors: Devito
authors: Claudia M
authors: CM
authors: Romano Sousa
mesh_terms: D016009:Chi-Square Distribution; D006801:Humans; D008964:Molar, Third / Q000002:abnormalities / Q000000981:diagnostic imaging* / Q000601:surgery; D009811:Odontometry / Q000379:methods*; D011300:Preoperative Care; D011862:Radiography, Panoramic; D012189:Retrospective Studies; D014071:Tooth Abnormalities / Q000453:epidemiology; D014081:Tooth Extraction; D014092:Tooth Root / Q000002:abnormalities / Q000000981:diagnostic imaging; D014095:Tooth, Impacted / Q000000981:diagnostic imaging* / Q000601:surgery; D014097:Tooth, Unerupted / Q000000981:diagnostic imaging* / Q000601:surgery