title: [Clinical investigation of root retention or removal during impacted mandibular third molar extraction].
abstract: OBJECTIVE
  To investigate the indication of root retention or removal during impacted mandibular third molar (IMTM) extraction and the relationship between the IMTM root and damage of mandibular alveolar nerve.
  
  
  METHODS
  The data of roots from 135 cases performing IMTM extraction were retrospectively analyzed to compare the location relationship between the IMTM and the mandibular canal.
  
  
  RESULTS
  (1)The relationship of 135 cases between the IMTM and the mandibular canal on panoramic radiographs was defined in three types, no contact type in 99 cases of IMTM(73%), point-contact type in 21 cases of IMTM(16%), and superimposition or line-contact type in 15 cases of IMTM(11%); (2)The roots of extracted IMTM were preserved in 18 cases(13%);(3)One month after the extraction of IMTM root, paresthesia in the lower lip disappeared in 17(94%) cases; 1 case had the symptom white resolved 8 months later.
  
  
  CONCLUSIONS
  The indication of root retention in the IMTM extraction was as follows: (1)Less than 3mm of residual root; (2)Dental pulp is not infected;(3)The superimposition or line-contact type between the root of IMTM and the mandibular canal.
authors: Department of Stomatology, Jiaxing Sanyi Hospital. Jiaxing 314000, Zhejiang Province, China. SHP516@126.com
authors: Hai-Ping
authors: HP
authors: Shen
mesh_terms: D006801:Humans; D008334:Mandible; D008340:Mandibular Nerve; D008964:Molar, Third; D011862:Radiography, Panoramic; D012189:Retrospective Studies; D014081:Tooth Extraction; D014092:Tooth Root; D014095:Tooth, Impacted