title: Regenerative endodontic treatment of an immature permanent tooth at an early stage of root development: a case report.
abstract: BACKGROUND
  Regenerative endodontic treatment (RET) has been used in treating nonvital immature permanent tooth whose root formation ranged from approximately two-thirds of the full root length to almost completely developed root with open apex at least 1.1 mm in diameter according to the reported cases. However, this case report was to introduce RET in an affected tooth at an early stage of root development.
  
  
  METHODS
  The premolar #29 in an 8-year-old girl had pulpal necrosis and apical periodontitis caused by the fracture of dens evaginatus. Its root was at the beginning of formation. Copious hemorrhagic drainage was observed after preparing of an access cavity. The canal was irrigated with 3% NaOCl solution, sterile normal saline, and chlorhexidine. Root dressing with triple antibiotic was then performed and left for 4 weeks. We used a K-file to create bleeding into the canal after flushing and drying the root canal. Mineral trioxide aggregate was carefully placed over the formed blood clot.
  
  
  RESULTS
  Clinical examination at 1, 3, 6, 9, and 12 months revealed an asymptomatic tooth. Radiographic examination revealed resolution of periapical radiolucency, increased thickening of the canal wall, and lengthening of the root, which demonstrated the continual development of the tooth root. Noticeably, the first-month postoperative radiograph showed radiopaque image in the root canal like an isolated island, which was gradually obvious during follow-up. Cone-beam computed tomography revealed that the calcification was attached with dentin wall in buccolingual direction, and the root canal was not completely obliterated.
  
  
  CONCLUSIONS
  RET is feasible for a tooth at an early stage of root development that has necrotic pulp and periapical lesion.
authors.affiliation: Department of Pediatric Dentistry, School of Stomatology, China Medical University, Shenyang, China. chenxu_cmu@sina.com
authors.forename: Xu
authors.initials: X
authors.lastname: Chen
authors.forename: Zhi-Fan
authors.initials: ZF
authors.lastname: Bao
authors.forename: Yao
authors.initials: Y
authors.lastname: Liu
authors.forename: Ming
authors.initials: M
authors.lastname: Liu
authors.forename: Xiao-Qing
authors.initials: XQ
authors.lastname: Jin
authors.forename: Xue-Bin
authors.initials: XB
authors.lastname: Xu
mesh_terms: D017607:Aluminum Compounds / Q000627:therapeutic use; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D056624:Apexification / Q000379:methods*; D001641:Bicuspid / Q000002:abnormalities / Q000503:physiopathology*; D017610:Calcium Compounds / Q000627:therapeutic use; D002126:Calcium Hydroxide / Q000627:therapeutic use; D002648:Child; D002710:Chlorhexidine / Q000627:therapeutic use; D054893:Cone-Beam Computed Tomography / Q000379:methods; D003786:Dental Pulp Cavity / Q000187:drug effects / Q000502:physiology; D003790:Dental Pulp Necrosis / Q000628:therapy; D004338:Drug Combinations; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D009805:Odontogenesis / Q000502:physiology*; D010087:Oxides / Q000627:therapeutic use; D010485:Periapical Periodontitis / Q000628:therapy; D012038:Regeneration / Q000502:physiology*; D012387:Root Canal Filling Materials / Q000627:therapeutic use; D012388:Root Canal Irrigants / Q000627:therapeutic use; D018915:Root Canal Preparation / Q000379:methods; D017640:Silicates / Q000627:therapeutic use; D012973:Sodium Hypochlorite / Q000627:therapeutic use; D014082:Tooth Fractures / Q000628:therapy; D014092:Tooth Root / Q000503:physiopathology*
chemical_list: D017607:Aluminum Compounds; D000900:Anti-Bacterial Agents; D017610:Calcium Compounds; D004338:Drug Combinations; D010087:Oxides; D012387:Root Canal Filling Materials; D012388:Root Canal Irrigants; D017640:Silicates; C086631:mineral trioxide aggregate; D012973:Sodium Hypochlorite; D002126:Calcium Hydroxide; D002710:Chlorhexidine